note : using access ( ) to check if a user is authorized to e. g. open a file before actually doing so using open ( ) creates a security hole, because the user might exploit the short time interval between checking and opening the file to manipulate it. note : i / o operations may fail even when access ( ) indicates that they would succeed, particularly for operations on network filesystems which may have permissions semantics beyond the usual posix permission - bit model. although windows supports chmod ( ), you can only set the file ' s read - only flag with it ( via the s _ iread constants or a corresponding integer value ). all other bits are ignored. | path, uid, gid ) | | path, uid, gid ) | '.. ' even if they are present in the directory. availability : macintosh, unix, windows. changed in version 2. 3 : on windows nt / 2k / xp and unix, if path is a unicode object, the result will be a list of unicode objects. 0666 ( octal ). the current umask value is first masked out from the mode. availability : macintosh, unix. fifos are pipes that can be accessed like regular files. fifos exist until they are deleted ( for example with os. unlink ( ) ). generally, fifos are used as rendezvous between ` ` client ' ' and ` ` server ' ' type processes : the server opens the fifo for reading, and the client opens it for writing. note that mkfifo ( ) doesn ' t open the fifo - - it just creates the rendezvous point. | filename [, mode = 0600, device ] ) | 0777 ( octal ). on some systems, mode is ignored. where it is used, the current umask value is first masked out. availability : macintosh, unix, windows. 0777 ( octal ). on some systems, mode is ignored. where it is used, the current umask value is first masked out. note : makedirs ( ) will become confused if the path elements to create include os. pardir. new in version 1. 5. 2. changed in version 2. 3 : this function now handles unc paths correctly. pathconf _ namesdictionary. for configuration variables not included in that mapping, passing an integer for name is also accepted. availability : macintosh, unix. if name is a string


. 3 : this function now handles unc paths correctly. pathconf _ namesdictionary. for configuration variables not included in that mapping, passing an integer for name is also accepted. availability : macintosh, unix. if name is a string and is not known, valueerror is raised. if a specific value for name is not supported by the host system, even if it is included in oserror is raised with errno. einval for the os. path. join ( os. path. dirname ( path ), result ). availability : macintosh, unix. > > > import os > > > statinfo = os. stat ( ' somefile. txt ' ) > > > statinfo ( 33188, 422511l, 769l, 1, 1032, 100, 926l, 1105022698, 1105022732, 1105022732 ) > > > statinfo. st _ size 926l > > > changed in version 2. 3 : if stat _ float _ times returns true, the time values are floats, measuring seconds. fractions of a second may be reported if the system supports that. on mac os, the times are always floats. see stat _ float _ times for further discussion. on some unix systems ( such as linux ), the following attributes may also be available : st _ blocks ( number of blocks allocated for file ), st _ blksize ( filesystem blocksize ), st _ rdev ( type of device if an inode device ). st _ flags ( user defined flags for file ). on other unix systems ( such as freebsd ), the following attributes may be available ( but may be only filled out if root tries to use them ) : st _ gen ( file generation number ), st _ birthtime ( time of file creation ). on mac os systems, the following attributes may also be available : st _ rsize, st _ creator, st _ type. on riscos systems, the following attributes are also available : st _ ftype ( file type ), st _ attrs ( attributes ), st _ obtype ( object type ). for backward compatibility, the return value of stat ( ) is also accessible as a tuple of at least 10 integers giving the most important ( and portable ) members of the stat structure, in the order st _ mode, st _ ino, st _ dev, st


the order given above. the standard module statvfs defines constants that are useful for extracting information from a statvfs structure when accessing it as a sequence ; this remains useful when writing code that needs to work with versions of python that don ' t support accessing the fields as attributes. changed in version 2. 2 : added access to values as attributes of the returned object. none. if given and not none, prefix is used to provide a short prefix to the filename. applications are responsible for properly creating and managing files created using paths returned by tempnam ( ) ; no automatic cleanup is provided. on unix, the environment variable tmpdir overrides dir, while on windows the tmp is used. the specific behavior of this function depends on the c library implementation ; some aspects are underspecified in system documentation. warning : use of tempnam ( ) is vulnerable to symlink attacks ; consider using tmpfile ( ) ( section 14. 1. 2 ) instead. availability : macintosh, unix, windows. none, then the file ' s access and modified times are set to the current time. otherwise, times must be a 2 - tuple of numbers, of the form ( atime, mtime ) which is used to set the access and modified times, respectively. whether a directory can be given for path depends on whether the operating system implements directories as files ( for example, windows does not ). note that the exact times you set here may not be returned by a subsequent stat ( ) call, depending on the resolution with which your operating system records access and modification times ; see stat ( ). changed in version 2. 0 : added support for nonefor times. availability : macintosh, unix, windows. ( dirpath, dirnames, filenames ). dirpath is a string, the path to the directory. dirnames is a list of the names of the subdirectories in dirpath '.. ' ). filenames is a list of the names of the non - directory files in dirpath. note that the names in the lists contain no path components. to get a full path ( which begins with top ) to a file or directory in if optional argument topdown is true or not specified, the triple for a directory is generated before the triples for any of its subdirectories ( directories are generated top down ). if topdown is false, the triple for a directory is generated


the concept of disability has changed significantly through history. at one point, disability was seen as the result of sin, either by the person with the disability or his or her parents. disability was associated with guilt and shame, and people with disabilities were hidden away. merriam - websteris definition of disability : limitation in the ability to pursue an occupation because of a physical or mental impairment ; lack of legal qualification to do something ; or a disqualification, restriction or disadvantage. most of the time, we apply these definitions to a person who dhase a disability. what if it is society that has the disability, not the individual? with the advent of modern medicine, a medical understanding of disability developed. in a medical model of disability, the person with a disability is seen as having an illness, which presumably should be cured. the person with a disability, as someone who is sick or diseased, is excused from normal life and responsibilities such as working, family obligations and household maintenance. the approach of the social security administration supports the idea of disability as something that excludes one from a normal life. to fit the administrationis definition of disability, a person must be able to prove that he or she is incapable of gainful employment. the inference is that by having a disability, one remains outside mainstream society. yet there is another way to view disability. this view considers disability as a normal part of life. after all, most of us will have a disability, whether temporary or permanent, at some time in our life. as many people with disabilities will attest, their disabilities are integral to what makes them who they are. it isnit the disability that needs to be changed. the physical and attitudinal barriers people with disabilities face are what need to change. for example, people who are unable to walk may still be able to move around as much as anyone with the use of wheelchairs and other assistive technology. the inability to use their limbs may be less of a limitation than heavy doors that donit open automatically or stairs that keep them from a building. similarly, culture and environment can dictate whether something is a disability. in a culture where healers and shamans regularly interact with a spirit world, hearing voices isnit a disability. only in societies where reading is essential to daily functioning is a learning disability recognized. in our society, a vision impairment that necessitates wearing glasses isnit considered a disability, but a mobility impairment that requires a person to use a walker is. disability is defined by context. it follows


second, are they capable of zooming in on particular areas to give reliable pictures of the future where you live? nobody much doubts that greenhouse gases like carbon dioxide accumulating in the atmosphere will cause warming. it would be a contradiction of 200 years of physics if they did not. but exactly how much warming will occur — and how it will be distributed across the globe and impact other climatic features like rainfall — depends on feedbacks in the climate system, the oceans, and the natural carbon cycle. the influence of some of these feedbacks is much less clear. one big issue is the influence of clouds. the models are pretty hopeless at predicting future cloud cover. and we can ’ t even be sure whether, overall, extra clouds would warm or cool the planet. ( clouds may cool us in the day, but will usually keep us warm at night. ) in the language of donald rumsfeld, we would call this problem a “ known unknown. ” and there may also be “ unknown unknowns. ” for instance, a paper in earth and planetary science letters in march reported finding fossilized ferns in central siberia that suggest that in the late cretaceous era, temperatures there were like modern - day florida. yet current climate models predict that the area should have had average temperatures around zero celsius. the british climate modeler involved in the study, paul valdes of bristol university, says this snapshot from the era of the dinosaurs could mean that “ the internal physics of our climate models are wrong. ” that the models may also be drastically underestimating likely warming in the 21st century. this uncertainty at the heart of the models seems surprising when the predictions of most global climate models seem to be in agreement. for more than a decade they have estimated that a doubling of carbon dioxide in the air will warm the world by between 1. 5 and 4. 5 degrees celsius. some experts think the consensus of the models is bogus. “ the modelers tend to tweak them to align them. the process is very incestuous, ” one leading british analyst on uncertainty in models told me. another, jerry ravetz, fellow at oxford university ’ s james martin institute for science and civilisation, says : “ the modelers are trained to be very myopic, and not to understand the uncertainty within their models. they become very skilled at solving the little problems and ignoring the big ones. ” these are serious charges. but the custodians of the big models say this is really a communications problem between them


and wrote the mass strike, in which she interpreted the 1905 russian revolution and demonstrated how the lessons of the events were applicable to all of europe. unfortunately, her writings did not have its intended effect since it was presented at a time when most socialists were no longer willing to discuss a revolution. rosa returned to germany in 1906 and was disappointed to discover that there was little enthusiasm over the russian revolution. the party congress in 1906 stated that while there may have been possibilities for a revolution, they no longer were present. furthermore, she found herself increasingly alone in her opinions in the party. although the spd agreed with her that the revolution was not likely to be just one big event, it would not go along with her belief that the revolution would be a series of events. as a result of the 1905 revolution, she had refined her beliefs of the revolution. she felt that the economic structure around her was becoming increasingly contradictory and more serious strikes would break out because of the economic situation. these strikes would be countered by governmental opposition and repression, which would educate the workers politically. this would lead to the gradual politicization of the entire strike movement, although the workers ’ strategy would still be to economically paralyze the whole country. although the government would subdue each strike, each strike would reemerge stronger and more determined than the previous one. the series of mass strikes would ultimately undermine the capitalist order as well as educate the proletariat of the course that history was taking. however, most socialist parties disagreed with rosa ’ s view of the revolution and the role of mass strikes. they believed that the voters would bring them political power and the trade union movement would provide some economic power. rosa ’ s appeal and popularity reached a pinnacle at the start of 1914. she went on trial for a statement she made the previous year in which she renounced fighting against the french and was subsequently sentenced to one year in prison. not only did she gain attention through this episode, but rosa also came to represent the spd persecuted by the government. the first world war broke out while she was in prison, and she was surprised by it. the brutality of the war horrified her and she worked with some groups to end the war, even though she did help pass a resolution for those who wanted to use the war to further the revolution. she spent most of wwi in prison and accomplished a great deal of work. among her writings, rosa referred to the russian revolution as the mightiest event of the world war, but felt that its ultimate effects depended on what western


book " the age of empathy : nature ' s lessons for a kinder society. " " we think that empathy evolved to take care of others that you need to take care of, especially, of course, between mother and offspring, which is universal in all the mammals, " de waal said. what it means to be fair de waal isn ' t sure that his monkeys have what a philosopher would call a " concept of justice " in an intellectual sense. but the emotional reactions researchers have observed indicates that there is, at a more basic level, a sense of justice among them. among the questions he investigates : if an animal gets more than another, is there is a feeling that this is somehow unjust? and if one shares food with another, is there an expectation of returning the favor? in a 2008 study, de waal and colleagues put two capuchin monkeys side by side and gave them a simple task to complete : giving a rock to the experimenter. they were given cucumbers as a reward for executing the task, and the monkeys obliged. but if one of the monkeys was given grapes, something interesting happened : as observed in a popular video that de waal showed in his ted talk, after receiving the first piece of cucumber, the capuchin monkey gives the experimenter a rock as expected. but upon seeing that the other monkey has grapes, the capuchin monkey throws the next piece of cucumber that it is given back at the researcher. like children, the monkeys feel they " need to get the same thing as somebody else, " de waal said. based on experiments such as these, de waal came to believe that the sense of fairness observed in monkeys is egocentric. the capuchin monkeys were upset, selfishly, when they didn ' t get the grapes that their neighbors received. de waal believed this model of fairness would apply to chimpanzees also. chimpanzees are so closely related to us that they share 99 % of their dna with humans. but the new study, which compares chimpanzees to young children, makes de waal rethink that view. " now with this experiment, we are thinking that they have a higher level, where they worry about reward division in general, " he said, " and it ' s now unclear how they differ from humans. " the new study : a human sense of fairness? in the new study, de waal and colleagues had chimpanzees and


reward division in general, " he said, " and it ' s now unclear how they differ from humans. " the new study : a human sense of fairness? in the new study, de waal and colleagues had chimpanzees and, separately, young children, play an " ultimatum game. " this is " the gold standard of fairness for humans " because it has been played all over the world, by people in different cultures, to show that, universally, humans appear to have a sense of fairness. the basic structure of an ultimatum game is that there are rewards that can be divided between two individuals. one proposes how to divide them and the other accepts or rejects this offer. if the receiver rejects, no rewards are given out. human trials have shown that people usually propose a generous division of the goodies, such as half and half or 60 % and 40 %, de waal said. in the version used in the new experiment, six adult chimpanzees and 20 human children, between ages 2 and 7, participated. the setup was such that a token could be traded for equal rewards for both partners, and a token that would give more goodies to the partner who made the choice. in some trials, one partner proposes a reward division to the other via a token, and the receiver must accept the token in order for both parties to get rewards. in others, the partner ' s acceptance is not required. the researchers found that chimpanzees and children both tended to make decisions about splitting rewards similarly to adult humans. in the situation where the responder could accept or reject the division of rewards, both chimpanzees and children tended to split the rewards with their partners. but when the partner was not given the opportunity to reject the proposal, chimps and kids tended to choose the selfish arrangement - - a token that favored the chooser. so, does this mean that chimpanzees show the same sense of fairness as humans? keith jensen of the university of manchester, who has conducted similar experiments in the past, isn ' t so sure. his results did not show that chimpanzees have a sense of fairness. jensen is concerned about the results of this new study because it ' s not clear that the responders knew that they could reject offers. none of the participants, human or chimp, ever rejected the offers of their partners. " the fact that responders never rejected nonzero offers suggests that they were not sensitive to unfairness but were only


| | this article needs additional citations for verification. ( february 2010 ) | opacity is the measure of impenetrability to electromagnetic or other kinds of radiation, especially visible light. in radiative transfer, it describes the absorption and scattering of radiation in a medium, such as a plasma, dielectric, shielding material, glass, etc. an opaque object is neither transparent ( allowing all light to pass through ) nor translucent ( allowing some light to pass through ). when light strikes an interface between two substances, in general some may be reflected, some absorbed, some scattered, and the rest transmitted ( also see refraction ). reflection can be diffuse, for example light reflecting off a white wall, or specular, for example light reflecting off a mirror. an opaque substance transmits no light, and therefore reflects, scatters, or absorbs all of it. both mirrors and carbon black are opaque. opacity depends on the frequency of the light being considered. for instance, some kinds of glass, while transparent in the visual range, are largely opaque to ultraviolet light. more extreme frequency - dependence is visible in the absorption lines of cold gases. opacity can be quantified in many ways ; for example, see the article mathematical descriptions of opacity. quantitative definition the words " opacity " and " opaque " are often used as colloquial terms for objects or media with the properties described above. however, there is also a specific, quantitative definition of " opacity ", used in astronomy, plasma physics, and other fields, given here. in this use, " opacity " is another term for the mass attenuation coefficient ( or, depending on context, mass absorption coefficient, the difference is described here ) at a particular frequency of electromagnetic radiation. more specifically, if a beam of light with frequency travels through a medium with opacity and mass density, both constant, then the intensity will be reduced with distance x according to the formula - x is the distance the light has traveled through the medium - is the intensity of light remaining at distance x - is the initial intensity of light, at for a given medium at a given frequency, the opacity has a numerical value that may range between 0 and infinity, with units of length2 / mass. planck and rosseland opacity it is customary to define the average opacity, calculated using a certain weighting scheme. planck opacity uses normalized planck black body radiation energy density distribution as


of the code follows : " military necessity, as understood by modern civilized nations, consists in the necessity of those measures which are indispensable for securing the ends of the war, and which are lawful according to the modern law and usages of war. military necessity admits of all direct destruction of life or limb of armed enemies, and of other persons whose destruction is incidentally unavoidable in the armed contests of the war ; it allows of the capturing of every armed enemy, and every enemy of importance to the hostile government, or of peculiar danger to the captor ; it allows of all destruction of property, and obstruction of the ways and channels of traffic, travel, or communication, and of all withholding of sustenance or means of life from the enemy ; of the appropriation of whatever an enemy ' s country affords necessary for the subsistence and safety of the army, and of such deception as does not involve the breaking of good faith either positively pledged, regarding agreements entered into during the war, or supposed by the modern law of war to exist. (... but... ) men who take up arms against one another in public war do not cease on this account to be moral beings, responsible to one another and to god. military necessity does not admit of cruelty — that is, the infliction of suffering for the sake of suffering or for revenge, nor of maiming or wounding except in fight, nor of torture to extort confessions. it does not admit of the use of poison in any way, nor of the wanton devastation of a district. it admits of deception, but disclaims acts of perfidy ; and, in general, military necessity does not include any act of hostility which makes the return to peace unnecessarily difficult. " this first statement of the previously uncodified rules and articles of war led to the first prosecution for war crimes — in the case of united states prisoners of war held in cruel and depraved conditions at andersonville, georgia, in which the confederate commandant of that camp was tried and hanged, the only confederate soldier to be punished by death in the aftermath of the entire civil war. in the years that followed, other states subscribed to limitations of their conduct, and numerous other treaties and bodies were created to regulate the conduct of states towards one another in terms of these treaties, including, but not limited to, the permanent court of arbitration in 1899 ; the hague and geneva conventions, the first of which was passed in


and availability of supra - national judicial organs operate routinely to provide assistance to that end. insofar as treaties are concerned, the vienna convention on the law of treaties writes on the topic of interpretation that : - " a treaty shall be interpreted in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose. " ( article 31 ( 1 ) ) this is actually a compromise between three different theories of interpretation : - the textual approach, a restrictive interpretation, which bases itself on the " ordinary meaning " of the text ; that approach assigns considerable weight to the actual text. - the subjective approach, which takes into consideration i. the idea behind the treaty, ii. treaties " in their context ", and iii. what the writers intended when they wrote the text. - a third approach, which bases itself on interpretation " in the light of its object and purpose ", i. e. the interpretation that best suits the goal of the treaty, also called " effective interpretation ". these are general rules of interpretation ; specific rules might exist in specific areas of international law. statehood and responsibility public international law establishes the framework and the criteria for identifying states as the principal actors in the international legal system. as the existence of a state presupposes control and jurisdiction over territory, international law deals with the acquisition of territory, state immunity and the legal responsibility of states in their conduct with each other. international law is similarly concerned with the treatment of individuals within state boundaries. there is thus a comprehensive regime dealing with group rights, the treatment of aliens, the rights of refugees, international crimes, nationality problems, and human rights generally. it further includes the important functions of the maintenance of international peace and security, arms control, the pacific settlement of disputes and the regulation of the use of force in international relations. even when the law is not able to stop the outbreak of war, it has developed principles to govern the conduct of hostilities and the treatment of prisoners. international law is also used to govern issues relating to the global environment, the global commons such as international waters and outer space, global communications, and world trade. in theory all states are sovereign and equal. as a result of the notion of sovereignty, the value and authority of international law is dependent upon the voluntary participation of states in its formulation, observance, and enforcement. although there may be exceptions, it is thought by many international academics that most states enter into legal commitments with other states out of enlight


of them, including the prohibition of genocide, slavery and the slave trade, wars of aggression, torture, and piracy, and that violation of these universal norms represents a crime, not only against the individual victims, but against humanity as a whole. states and individuals who subscribe to this view opine that, in the case of the individual responsible for violation of international law, he " is become, like the pirate and the slave trader before him, hostis humani generis, an enemy of all mankind ", and thus subject to prosecution in a fair trial before any fundamentally just tribunal, through the exercise of universal jurisdiction. though the european democracies tend to support broad, universalistic interpretations of international law, many other democracies have differing views on international law. several democracies, including india, israel and the united states, take a flexible, eclectic approach, recognizing aspects of public international law such as territorial rights as universal, regarding other aspects as arising from treaty or custom, and viewing certain aspects as not being subjects of public international law at all. democracies in the developing world, due to their past colonial histories, often insist on non - interference in their internal affairs, particularly regarding human rights standards or their peculiar institutions, but often strongly support international law at the bilateral and multilateral levels, such as in the united nations, and especially regarding the use of force, disarmament obligations, and the terms of the un charter. international human rights - universal declaration of human rights - declaration of fundamental rights at work - international labour organization international economic law | this section requires expansion. ( october 2012 ) | war and conflicts | this section requires expansion. ( october 2012 ) | international criminal law | this section requires expansion. ( october 2012 ) | international courts and enforcement it is probably the case that almost all nations observe almost all principles of international law and almost all of their obligations almost all the time. since international law has no established compulsory judicial system for the settlement of disputes or a coercive penal system, it is not as straightforward as managing breaches within a domestic legal system. however, there are means by which breaches are brought to the attention of the international community and some means for resolution. for example, there are judicial or quasi - judicial tribunals in international law in certain areas such as trade and human rights. the formation of the united nations, for example, created a means for the world community to enforce international law upon members that violate its charter through the security council. since international law exists in a legal environment


in certain areas such as trade and human rights. the formation of the united nations, for example, created a means for the world community to enforce international law upon members that violate its charter through the security council. since international law exists in a legal environment without an overarching " sovereign " ( i. e., an external power able and willing to compel compliance with international norms ), " enforcement " of international law is very different than in the domestic context. in many cases, enforcement takes on coasian characteristics, where the norm is self - enforcing. in other cases, defection from the norm can pose a real risk, particularly if the international environment is changing. when this happens, and if enough states ( or enough powerful states ) continually ignore a particular aspect of international law, the norm may actually change according to concepts of customary international law. for example, prior to world war i, unrestricted submarine warfare was considered a violation of international law and ostensibly the casus belli for the united states ' declaration of war against germany. by world war ii, however, the practice was so widespread that during the nuremberg trials, the charges against german admiral karl donitz for ordering unrestricted submarine warfare were dropped, notwithstanding that the activity constituted a clear violation of the second london naval treaty of 1936. enforcement by states apart from a state ' s natural inclination to uphold certain norms, the force of international law comes from the pressure that states put upon one another to behave consistently and to honor their obligations. as with any system of law, many violations of international law obligations are overlooked. if addressed, it may be through diplomacy and the consequences upon an offending state ' s reputation, submission to international judicial determination, arbitration, sanctions or force including war. though violations may be common in fact, states try to avoid the appearance of having disregarded international obligations. states may also unilaterally adopt sanctions against one another such as the severance of economic or diplomatic ties, or through reciprocal action. in some cases, domestic courts may render judgment against a foreign state ( the realm of private international law ) for an injury, though this is a complicated area of law where international law intersects with domestic law. it is implicit in the westphalian system of nation - states, and explicitly recognized under article 51 of the charter of the united nations, that all states have the inherent right to individual and collective self - defense if an armed attack occurs against them. article 51 of the un charter guarantees the right of states to defend themselves until ( and unless ) the security


the charter of the united nations, that all states have the inherent right to individual and collective self - defense if an armed attack occurs against them. article 51 of the un charter guarantees the right of states to defend themselves until ( and unless ) the security council takes measures to keep the peace. enforcement by international bodies violations of the un charter by members of the united nations may be raised by the aggrieved state in the general assembly for debate. the general assembly cannot make binding resolutions, only ' recommendations ', but through its adoption of the " uniting for peace " resolution ( a / res / 377 a ), of 3 november 1950, the assembly declared that it has the power to authorize the use of force, under the terms of the un charter, in cases of breaches of the peace or acts of aggression, provided that the security council, owing to the negative vote of a permanent member, fails to act to address the situation. the assembly also declared, by its adoption of resolution 377 a, that it could call for other collective measures — such as economic and diplomatic sanctions — in situations constituting the milder " threat to the peace ". the uniting for peace resolution was initiated by the united states in 1950, shortly after the outbreak of the korean war, as a means of circumventing possible future soviet vetoes in the security council. the legal significance of the resolution is unclear, given that the general assembly cannot issue binding resolutions. however, it was never argued by the " joint seven - powers " that put forward the draft resolution, during the corresponding discussions, that it in any way afforded the assembly new powers. instead, they argued that the resolution simply declared what the assembly ' s powers already were, according to the un charter, in the case of a dead - locked security council. the soviet union was the only permanent member of the security council to vote against the charter interpretations that were made law by the assembly ' s adoption of resolution 377 a. alleged violations of the charter can also be raised by states in the security council. the security council could subsequently pass resolutions under chapter vi of the un charter to recommend the " pacific resolution of disputes. " such resolutions are not binding under international law, though they usually are expressive of the council ' s convictions. in rare cases, the security council can adopt resolutions under chapter vii of the un charter, related to " threats to peace, breaches of the peace and acts of aggression, " which are legally binding under international law, and can be followed up with


in rare cases, the security council can adopt resolutions under chapter vii of the un charter, related to " threats to peace, breaches of the peace and acts of aggression, " which are legally binding under international law, and can be followed up with economic sanctions, military action, and similar uses of force through the auspices of the united nations. it has been argued that resolutions passed outside of chapter vii can also be binding ; the legal basis for that is the council ' s broad powers under article 24 ( 2 ), which states that " in discharging these duties ( exercise of primary responsibility in international peace and security ), it shall act in accordance with the purposes and principles of the united nations ". the mandatory nature of such resolutions was upheld by the international court of justice ( icj ) in its advisory opinion on namibia. the binding nature of such resolutions can be deduced from an interpretation of their language and intent. states can also, upon mutual consent, submit disputes for arbitration by the international court of justice, located in the hague, netherlands. the judgments given by the court in these cases are binding, although it possesses no means to enforce its rulings. the court may give an advisory opinion on any legal question at the request of whatever body may be authorized by or in accordance with the charter of the united nations to make such a request. some of the advisory cases brought before the court have been controversial with respect to the court ' s competence and jurisdiction. often enormously complicated matters, icj cases ( of which there have been less than 150 since the court was created from the permanent court of international justice in 1945 ) can stretch on for years and generally involve thousands of pages of pleadings, evidence, and the world ' s leading specialist public international lawyers. as of june 2009, there are 15 cases pending at the icj. decisions made through other means of arbitration may be binding or non - binding depending on the nature of the arbitration agreement, whereas decisions resulting from contentious cases argued before the icj are always binding on the involved states. though states ( or increasingly, international organizations ) are usually the only ones with standing to address a violation of international law, some treaties, such as the international covenant on civil and political rights have an optional protocol that allows individuals who have had their rights violated by member states to petition the international human rights committee. investment treaties commonly and routinely provide for enforcement by individuals or investing entities. and commercial agreements of foreigners with sovereign governments may be enforced on the international plane. international legal theory international legal theory comprises a


violated by member states to petition the international human rights committee. investment treaties commonly and routinely provide for enforcement by individuals or investing entities. and commercial agreements of foreigners with sovereign governments may be enforced on the international plane. international legal theory international legal theory comprises a variety of theoretical and methodological approaches used to explain and analyse the content, formation and effectiveness of public international law and institutions and to suggest improvements. some approaches center on the question of compliance : why states follow international norms in the absence of a coercitive power that ensures compliance. other approaches focus on the problem of the formation of international rules : why states voluntarily adopt international law norms, that limit their freedom of action, in the absence of a world legislature ; while other perspectives are policy oriented : they elaborate theoretical frameworks and instruments to criticize the existing norms and to make suggestions on how to improve them. some of these approaches are based on domestic legal theory, some are interdisciplinary, and others have been developed expressly to analyse international law. classical approaches to international legal theory are the natural law, the eclectic and the legal positivism schools of thought. natural law the natural law approach argues that international norms should be based on axiomatic truths. 16th century natural law writer, francisco de vitoria, a professor of theology at the university of salamanca, examined the questions of the just war, the spanish authority in the americas, and the rights of the native american peoples. eclectic or grotian school in 1625 hugo grotius argued that nations as well as persons ought to be governed by universal principle based on morality and divine justice while the relations among polities ought to be governed by the law of peoples, the jus gentium, established by the consent of the community of nations on the basis of the principle of pacta sunt servanda, that is, on the basis of the observance of commitments. on his part, emmerich de vattel argued instead for the equality of states as articulated by 18th century natural law and suggested that the law of nations was composed of custom and law on the one hand, and natural law on the other. during the 17th century, the basic tenets of the grotian or eclectic school, especially the doctrines of legal equality, territorial sovereignty, and independence of states, became the fundamental principles of the european political and legal system and were enshrined in the 1648 peace of westphalia. legal positivism the early positivist school emphasized the importance of custom and treaties as sources of international law. 16th century


, became the fundamental principles of the european political and legal system and were enshrined in the 1648 peace of westphalia. legal positivism the early positivist school emphasized the importance of custom and treaties as sources of international law. 16th century alberico gentili used historical examples to posit that positive law ( jus voluntarium ) was determined by general consent. cornelius van bynkershoek asserted that the bases of international law were customs and treaties commonly consented to by various states, while john jacob moser emphasized the importance of state practice in international law. the positivism school narrowed the range of international practice that might qualify as law, favouring rationality over morality and ethics. the 1815 congress of vienna marked the formal recognition of the political and international legal system based on the conditions of europe. modern legal positivists consider international law as a unified system of rules that emanates from the states ' will. international law, as it is, is an " objective " reality that needs to be distinguished from law " as it should be. " classic positivism demands rigorous tests for legal validity and it deems irrelevant all extralegal arguments. see also - consular law - diplomatic law - international aviation law - international criminal law - international environmental law - international human rights law - international humanitarian law - international space law - international trade law - law of state responsibility - rule according to higher law - united nations convention on the law of the sea - use of force continuum - diplomatic recognition - environmental agreements - global administrative law - international community - international court of justice - international criminal court - international criminal tribunal for rwanda - international criminal tribunal for the former yugoslavia - international labour organization - international law commission - international legal theory - hans kelsen - laws of war - legal status of the holy see - list of international public law topics - list of treaties - personal jurisdiction over international defendants in the united states - prize law - sources of international law - sovereign state - territorial integrity - third world approaches to international law ( twail ) - united nations - united nations general assembly sixth committee ( legal ) - university for peace - world government - history of public international law - columbia law school, mckeever, 2003 — definition of international law - greig, d. w., international law, 2nd edn ( butterworths : london, 1976 ) - janis, m. and noyes, j. international law " : cases and commentary ( 3rd ed. ), prosecutor v. furundzi


support vector machine in machine learning, support vector machines ( svms, also support vector networks ) are supervised learning models with associated learning algorithms that analyze data and recognize patterns, used for classification and regression analysis. the basic svm takes a set of input data and predicts, for each given input, which of two possible classes forms the output, making it a non - probabilistic binary linear classifier. given a set of training examples, each marked as belonging to one of two categories, an svm training algorithm builds a model that assigns new examples into one category or the other. an svm model is a representation of the examples as points in space, mapped so that the examples of the separate categories are divided by a clear gap that is as wide as possible. new examples are then mapped into that same space and predicted to belong to a category based on which side of the gap they fall on. in addition to performing linear classification, svms can efficiently perform non - linear classification using what is called the kernel trick, implicitly mapping their inputs into high - dimensional feature spaces. formal definition more formally, a support vector machine constructs a hyperplane or set of hyperplanes in a high - or infinite - dimensional space, which can be used for classification, regression, or other tasks. intuitively, a good separation is achieved by the hyperplane that has the largest distance to the nearest training data point of any class ( so - called functional margin ), since in general the larger the margin the lower the generalization error of the classifier. whereas the original problem may be stated in a finite dimensional space, it often happens that the sets to discriminate are not linearly separable in that space. for this reason, it was proposed that the original finite - dimensional space be mapped into a much higher - dimensional space, presumably making the separation easier in that space. to keep the computational load reasonable, the mappings used by svm schemes are designed to ensure that dot products may be computed easily in terms of the variables in the original space, by defining them in terms of a kernel function selected to suit the problem. the hyperplanes in the higher - dimensional space are defined as the set of points whose dot product with a vector in that space is constant. the vectors defining the hyperplanes can be chosen to be linear combinations with parameters of images of feature vectors that occur in the data base. with this choice of a hyperplane, the points in the feature space that are mapped into the hyperplane are defined by the relation :


hyperplanes can be chosen to be linear combinations with parameters of images of feature vectors that occur in the data base. with this choice of a hyperplane, the points in the feature space that are mapped into the hyperplane are defined by the relation : note that if becomes small as grows further away from, each element in the sum measures the degree of closeness of the test point to the corresponding data base point. in this way, the sum of kernels above can be used to measure the relative nearness of each test point to the data points originating in one or the other of the sets to be discriminated. note the fact that the set of points mapped into any hyperplane can be quite convoluted as a result, allowing much more complex discrimination between sets which are not convex at all in the original space. classifying data is a common task in machine learning. suppose some given data points each belong to one of two classes, and the goal is to decide which class a new data point will be in. in the case of support vector machines, a data point is viewed as a p - dimensional vector ( a list of p numbers ), and we want to know whether we can separate such points with a ( p − 1 ) - dimensional hyperplane. this is called a linear classifier. there are many hyperplanes that might classify the data. one reasonable choice as the best hyperplane is the one that represents the largest separation, or margin, between the two classes. so we choose the hyperplane so that the distance from it to the nearest data point on each side is maximized. if such a hyperplane exists, it is known as the maximum - margin hyperplane and the linear classifier it defines is known as a maximum margin classifier ; or equivalently, the perceptron of optimal stability. linear svm given some training data, a set of n points of the form where the yi is either 1 or −1, indicating the class to which the point belongs. each is a p - dimensional real vector. we want to find the maximum - margin hyperplane that divides the points having from those having. any hyperplane can be written as the set of points satisfying if the training data are linearly separable, we can select two hyperplanes in a way that they separate the data and there are no points between them, and then try to maximize their distance. the region bounded by them is called " the margin ". these hyperplanes can be described by the equations by using geometry, we find


a way that they separate the data and there are no points between them, and then try to maximize their distance. the region bounded by them is called " the margin ". these hyperplanes can be described by the equations by using geometry, we find the distance between these two hyperplanes is, so we want to minimize. as we also have to prevent data points from falling into the margin, we add the following constraint : for each either - of the first class - of the second. this can be rewritten as : we can put this together to get the optimization problem : minimize ( in ) subject to ( for any ) primal form the optimization problem presented in the preceding section is difficult to solve because it depends on | | w | |, the norm of w, which involves a square root. fortunately it is possible to alter the equation by substituting | | w | | with ( the factor of 1 / 2 being used for mathematical convenience ) without changing the solution ( the minimum of the original and the modified equation have the same w and b ). this is a quadratic programming optimization problem. more clearly : minimize ( in ) subject to ( for any ) by introducing lagrange multipliers, the previous constrained problem can be expressed as that is we look for a saddle point. in doing so all the points which can be separated as do not matter since we must set the corresponding to zero. this problem can now be solved by standard quadratic programming techniques and programs. the " stationary " karush – kuhn – tucker condition implies that the solution can be expressed as a linear combination of the training vectors only a few will be greater than zero. the corresponding are exactly the support vectors, which lie on the margin and satisfy. from this one can derive that the support vectors also satisfy which allows one to define the offset. in practice, it is more robust to average over all support vectors : dual form writing the classification rule in its unconstrained dual form reveals that the maximum margin hyperplane and therefore the classification task is only a function of the support vectors, the training data that lie on the margin. using the fact that and substituting, one can show that the dual of the svm reduces to the following optimization problem : maximize ( in ) subject to ( for any ) and to the constraint from the minimization in here the kernel is defined by. can be computed thanks to the terms : biased and unbiased hyperplanes for simplicity reasons, sometimes it is required that the hyperplane pass through the origin


any ) and to the constraint from the minimization in here the kernel is defined by. can be computed thanks to the terms : biased and unbiased hyperplanes for simplicity reasons, sometimes it is required that the hyperplane pass through the origin of the coordinate system. such hyperplanes are called unbiased, whereas general hyperplanes not necessarily passing through the origin are called biased. an unbiased hyperplane can be enforced by setting in the primal optimization problem. the corresponding dual is identical to the dual given above without the equality constraint soft margin in 1995, corinna cortes and vladimir n. vapnik suggested a modified maximum margin idea that allows for mislabeled examples. if there exists no hyperplane that can split the " yes " and " no " examples, the soft margin method will choose a hyperplane that splits the examples as cleanly as possible, while still maximizing the distance to the nearest cleanly split examples. the method introduces non - negative slack variables,, which measure the degree of misclassification of the data the objective function is then increased by a function which penalizes non - zero, and the optimization becomes a trade off between a large margin and a small error penalty. if the penalty function is linear, the optimization problem becomes : subject to ( for any ) this constraint in ( 2 ) along with the objective of minimizing can be solved using lagrange multipliers as done above. one has then to solve the following problem : dual form maximize ( in ) subject to ( for any ) the key advantage of a linear penalty function is that the slack variables vanish from the dual problem, with the constant c appearing only as an additional constraint on the lagrange multipliers. for the above formulation and its huge impact in practice, cortes and vapnik received the 2008 acm paris kanellakis award. nonlinear penalty functions have been used, particularly to reduce the effect of outliers on the classifier, but unless care is taken the problem becomes non - convex, and thus it is considerably more difficult to find a global solution. nonlinear classification the original optimal hyperplane algorithm proposed by vapnik in 1963 was a linear classifier. however, in 1992, bernhard e. boser, isabelle m. guyon and vladimir n. vapnik suggested a way to create nonlinear classifiers by applying the kernel trick ( originally proposed by aizerman et al. ) to maximum - margin hyperplanes. the resulting algorithm is formally similar, except that every dot product is


vladimir n. vapnik suggested a way to create nonlinear classifiers by applying the kernel trick ( originally proposed by aizerman et al. ) to maximum - margin hyperplanes. the resulting algorithm is formally similar, except that every dot product is replaced by a nonlinear kernel function. this allows the algorithm to fit the maximum - margin hyperplane in a transformed feature space. the transformation may be nonlinear and the transformed space high dimensional ; thus though the classifier is a hyperplane in the high - dimensional feature space, it may be nonlinear in the original input space. if the kernel used is a gaussian radial basis function, the corresponding feature space is a hilbert space of infinite dimensions. maximum margin classifiers are well regularized, so the infinite dimensions do not spoil the results. some common kernels include : - polynomial ( homogeneous ) : - polynomial ( inhomogeneous ) : - gaussian radial basis function :, for sometimes parametrized using - hyperbolic tangent :, for some ( not every ) and the kernel is related to the transform by the equation. the value w is also in the transformed space, with dot products with w for classification can again be computed by the kernel trick, i. e.. however, there does not in general exist a value w ' such that svms belong to a family of generalized linear classifiers and can be interpreted as an extension of the perceptron. they can also be considered a special case of tikhonov regularization. a special property is that they simultaneously minimize the empirical classification error and maximize the geometric margin ; hence they are also known as maximum margin classifiers. a comparison of the svm to other classifiers has been made by meyer, leisch and hornik. parameter selection the effectiveness of svm depends on the selection of kernel, the kernel ' s parameters, and soft margin parameter c. a common choice is a gaussian kernel, which has a single parameter γ. the best combination of c and γ is often selected by a grid search with exponentially growing sequences of c and γ, for example, ;. typically, each combination of parameter choices is checked using cross validation, and the parameters with best cross - validation accuracy are picked. the final model, which is used for testing and for classifying new data, is then trained on the whole training set using the selected parameters. potential drawbacks of the svm are the following three aspects : - uncalibrated class membership probabilities - the svm is only directly applicable


for classifying new data, is then trained on the whole training set using the selected parameters. potential drawbacks of the svm are the following three aspects : - uncalibrated class membership probabilities - the svm is only directly applicable for two - class tasks. therefore, algorithms that reduce the multi - class task to several binary problems have to be applied ; see the multi - class svm section. - parameters of a solved model are difficult to interpret. multiclass svm multiclass svm aims to assign labels to instances by using support vector machines, where the labels are drawn from a finite set of several elements. - building binary classifiers which distinguish between ( i ) one of the labels and the rest ( one - versus - all ) or ( ii ) between every pair of classes ( one - versus - one ). classification of new instances for the one - versus - all case is done by a winner - takes - all strategy, in which the classifier with the highest output function assigns the class ( it is important that the output functions be calibrated to produce comparable scores ). for the one - versus - one approach, classification is done by a max - wins voting strategy, in which every classifier assigns the instance to one of the two classes, then the vote for the assigned class is increased by one vote, and finally the class with the most votes determines the instance classification. - directed acyclic graph svm ( dagsvm ) - error - correcting output codes crammer and singer proposed a multiclass svm method which casts the multiclass classification problem into a single optimization problem, rather than decomposing it into multiple binary classification problems. see also lee, lin and wahba. transductive support vector machines transductive support vector machines extend svms in that they could also treat partially labeled data in semi - supervised learning by following the principles of transduction. here, in addition to the training set, the learner is also given a set of test examples to be classified. formally, a transductive support vector machine is defined by the following primal optimization problem : minimize ( in ) subject to ( for any and any ) transductive support vector machines were introduced by vladimir n. vapnik in 1998. structured svm svms have been generalized to structured svms, where the label space is structured and of possibly infinite size. a version of svm for regression was proposed in 1996 by vladimir n. vapnik, harris drucker, christopher j. c.


1995. http : / / www. springerlink. com / content / k238jx04hm87j80g / - * press, william h. ; teukolsky, saul a. ; vetterling, william t. ; flannery, b. p. ( 2007 ). " section 16. 5. support vector machines ". numerical recipes : the art of scientific computing ( 3rd ed. ). new york : cambridge university press. isbn 978 - 0 - 521 - 88068 - 8. - acm website, press release of march 17th 2009. http : / / www. acm. org / press - room / news - releases / awards - 08 - groupa - aizerman, mark a. ; braverman, emmanuel m. ; and rozonoer, lev i. ( 1964 ). " theoretical foundations of the potential function method in pattern recognition learning ". automation and remote control 25 : 821 – 837. - boser, bernhard e. ; guyon, isabelle m. ; and vapnik, vladimir n. ; a training algorithm for optimal margin classifiers. in haussler, david ( editor ) ; 5th annual acm workshop on colt, pages 144 – 152, pittsburgh, pa, 1992. acm press - meyer, david ; leisch, friedrich ; and hornik, kurt ; the support vector machine under test, neurocomputing 55 ( 1 – 2 ) : 169 – 186, 2003 http : / / dx. doi. org / 10. 1016 / s0925 - 2312 ( 03 ) 00431 - 4 - hsu, chih - wei ; chang, chih - chung ; and lin, chih - jen ( 2003 ). a practical guide to support vector classification. department of computer science and information engineering, national taiwan university. http : / / www. csie. ntu. edu. tw / ~ cjlin / papers / guide / guide. pdf. - duan, kai - bo ; and keerthi, s. sathiya ( 2005 ). " which is the best multiclass svm method? an empirical study ". proceedings of the sixth international workshop on multiple classifier systems. lecture notes in computer science 3541 : 278. doi : 10. 1007 / 11494683 _ 28. isbn 978 - 3 - 540 - 26306 - 7. - hsu, chih - wei


classifier systems. lecture notes in computer science 3541 : 278. doi : 10. 1007 / 11494683 _ 28. isbn 978 - 3 - 540 - 26306 - 7. - hsu, chih - wei ; and lin, chih - jen ( 2002 ). " a comparison of methods for multiclass support vector machines ". ieee transactions on neural networks. - platt, john ; cristianini, n. ; and shawe - taylor, j. ( 2000 ). " large margin dags for multiclass classification ". in solla, sara a. ; leen, todd k. ; and muller, klaus - robert ; eds. advances in neural information processing systems. mit press. pp. 547 – 553. - dietterich, thomas g. ; and bakiri, ghulum ; bakiri ( 1995 ). " solving multiclass learning problems via error - correcting output codes ". journal of artificial intelligence research, vol. 2 2 : 263 – 286. arxiv : cs / 9501101. bibcode : 1995cs........ 1101d. unknown parameter - crammer, koby ; and singer, yoram ( 2001 ). " on the algorithmic implementation of multiclass kernel - based vector machines ". j. of machine learning research 2 : 265 – 292. - lee, y. ; lin, y. ; and wahba, g. ( 2001 ). " multicategory support vector machines ". computing science and statistics 33. - lee, y. ; lin, y. ; and wahba, g. ( 2004 ). " multicategory support vector machines, theory, and application to the classification of microarray data and satellite radiance data ". journal of the american statistical association 99 ( 465 ) : 67 – 81. doi : 10. 1198 / 016214504000000098. - joachims, thorsten ; " transductive inference for text classification using support vector machines ", proceedings of the 1999 international conference on machine learning ( icml 1999 ), pp. 200 - 209. - drucker, harris ; burges, christopher j. c. ; kaufman, linda ; smola, alexander j. ; and vapnik, vladimir n. ( 1997 ) ; " support vector regression machines ", in advances in neural information processing systems 9, nips 1996,


, christopher j. c. ; kaufman, linda ; smola, alexander j. ; and vapnik, vladimir n. ( 1997 ) ; " support vector regression machines ", in advances in neural information processing systems 9, nips 1996, 155 – 161, mit press. - suykens, johan a. k. ; vandewalle, joos p. l. ; least squares support vector machine classifiers, neural processing letters, vol. 9, no. 3, jun. 1999, pp. 293 – 300. - ferris, michael c. ; and munson, todd s. ( 2002 ). " interior - point methods for massive support vector machines ". siam journal on optimization 13 ( 3 ) : 783 – 804. doi : 10. 1137 / s1052623400374379. - burges, christopher j. c. ; a tutorial on support vector machines for pattern recognition, data mining and knowledge discovery 2 : 121 – 167, 1998 - www. kernel - machines. org ( general information and collection of research papers ) - teknomo, k. svm tutorial using spreadsheet visual introduction to svm. - www. support - vector - machines. org ( literature, review, software, links related to support vector machines — academic site ) - videolectures. net ( svm - related video lectures ) - animation clip : svm with polynomial kernel visualization - fletcher, tristan ; a very basic svm tutorial for complete beginners - karatzoglou, alexandros et al. ; support vector machines in r, journal of statistical software april 2006, volume 15, issue 9. - shogun ( toolbox ) contains about 20 different implementations of svms, written in c + + with matlab, octave, python, r, java, lua, ruby and c # interffaces - libsvm libsvm is a library of svms which is actively patched - liblinear liblinear is a library for large linear classification including some svms - flssvm flssvm is a least squares svm implementation written in fortran - shark shark is a c + + machine learning library implementing various types of svms - dlib dlib is a c + + library for working with kernel methods and svms - svm light is a collection of software tools for learning and classification using svm. - stanford university andrew ng video on sv


various types of svms - dlib dlib is a c + + library for working with kernel methods and svms - svm light is a collection of software tools for learning and classification using svm. - stanford university andrew ng video on svm - theodoridis, sergios ; and koutroumbas, konstantinos ; " pattern recognition ", 4th edition, academic press, 2009, isbn 978 - 1 - 59749 - 272 - 0 - cristianini, nello ; and shawe - taylor, john ; an introduction to support vector machines and other kernel - based learning methods, cambridge university press, 2000. isbn 0 - 521 - 78019 - 5 ( svm book ) - huang, te - ming ; kecman, vojislav ; and kopriva, ivica ( 2006 ) ; kernel based algorithms for mining huge data sets, in supervised, semi - supervised, and unsupervised learning, springer - verlag, berlin, heidelberg, 260 pp. 96 illus., hardcover, isbn 3 - 540 - 31681 - 7 - kecman, vojislav ; learning and soft computing — support vector machines, neural networks, fuzzy logic systems, the mit press, cambridge, ma, 2001. - scholkopf, bernhard ; and smola, alexander j. ; learning with kernels, mit press, cambridge, ma, 2002. isbn 0 - 262 - 19475 - 9 - scholkopf, bernhard ; burges, christopher j. c. ; and smola, alexander j. ( editors ) ; advances in kernel methods : support vector learning, mit press, cambridge, ma, 1999. isbn 0 - 262 - 19416 - 3. - shawe - taylor, john ; and cristianini, nello ; kernel methods for pattern analysis, cambridge university press, 2004. isbn 0 - 521 - 81397 - 2 ( kernel methods book ) - steinwart, ingo ; and christmann, andreas ; support vector machines, springer - verlag, new york, 2008. isbn 978 - 0 - 387 - 77241 - 7 ( svm book ) - tan, peter jing ; and dowe, david l. ( 2004 ) ; mml inference of oblique decision trees, lecture notes in artificial intelligence ( lnai ) 3339, springer - verlag, pp1082 - 1088. ( this paper uses minimum message length ( mml ) and actually incorporates probabilistic support


##l inference of oblique decision trees, lecture notes in artificial intelligence ( lnai ) 3339, springer - verlag, pp1082 - 1088. ( this paper uses minimum message length ( mml ) and actually incorporates probabilistic support vector machines in the leaves of decision trees. ) - vapnik, vladimir n. ; the nature of statistical learning theory, springer - verlag, 1995. isbn 0 - 387 - 98780 - 0 - vapnik, vladimir n. ; and kotz, samuel ; estimation of dependences based on empirical data, springer, 2006. isbn 0 - 387 - 30865 - 2, 510 pages [ this is a reprint of vapnik ' s early book describing philosophy behind svm approach. the 2006 appendix describes recent development ]. - fradkin, dmitriy ; and muchnik, ilya ; support vector machines for classification in abello, j. ; and carmode, g. ( eds ) ; discrete methods in epidemiology, dimacs series in discrete mathematics and theoretical computer science, volume 70, pp. 13 – 20, 2006.. succinctly describes theoretical ideas behind svm. - bennett, kristin p. ; and campbell, colin ; support vector machines : hype or hallelujah?, sigkdd explorations, 2, 2, 2000, 1 – 13.. excellent introduction to svms with helpful figures. - ivanciuc, ovidiu ; applications of support vector machines in chemistry, in reviews in computational chemistry, volume 23, 2007, pp. 291 – 400. reprint available : - catanzaro, bryan ; sundaram, narayanan ; and keutzer, kurt ; fast support vector machine training and classification on graphics processors, in international conference on machine learning, 2008 - campbell, colin ; and ying, yiming ; learning with support vector machines, 2011, morgan and claypool. isbn 978 - 1 - 60845 - 616 - 1.


the troposphere is the lowest portion of earth ' s atmosphere. it contains approximately 80 % of the atmosphere ' s mass and 99 % of its water vapor and aerosols. the average depth of the troposphere is approximately 17 km ( 11 mi ) in the middle latitudes. it is deeper in the tropics, up to 20 km ( 12 mi ), and shallower near the polar regions, at 7 km ( 4. 3 mi ) in summer, and indistinct in winter. the lowest part of the troposphere, where friction with the earth ' s surface influences air flow, is the planetary boundary layer. this layer is typically a few hundred meters to 2 km ( 1. 2 mi ) deep depending on the landform and time of day. the border between the troposphere and stratosphere, called the tropopause, is a temperature inversion. the word troposphere derives from the greek : tropos for " change " reflecting the fact that turbulent mixing plays an important role in the troposphere ' s structure and behavior. most of the phenomena we associate with day - to - day weather occur in the troposphere. pressure and temperature structure the chemical composition of the troposphere is essentially uniform, with the notable exception of water vapor. the source of water vapor is at the surface through the processes of evaporation and transpiration. furthermore the temperature of the troposphere decreases with height, and saturation vapor pressure decreases strongly as temperature drops, so the amount of water vapor that can exist in the atmosphere decreases strongly with height. thus the proportion of water vapor is normally greatest near the surface and decreases with height. the pressure of the atmosphere is maximum at sea level and decreases with higher altitude. this is because the atmosphere is very nearly in hydrostatic equilibrium, so that the pressure is equal to the weight of air above a given point. the change in pressure with height, therefore can be equated to the density with this hydrostatic equation : since temperature in principle also depends on altitude, one needs a second equation to determine the pressure as a function of height, as discussed in the next section. * the temperature of the troposphere generally decreases as altitude increases. the rate at which the temperature decreases,, is called the environmental lapse rate ( elr ). the elr is nothing more than the difference in temperature between the surface and the tropopause divided by the height. the reason for this temperature difference is the absorption of the


,, is called the environmental lapse rate ( elr ). the elr is nothing more than the difference in temperature between the surface and the tropopause divided by the height. the reason for this temperature difference is the absorption of the sun ' s energy occurs at the ground which heats the lower levels of the atmosphere, and the radiation of heat occurs at the top of the atmosphere cooling the earth, this process maintaining the overall heat balance of the earth. as parcels of air in the atmosphere rise and fall, they also undergo changes in temperature for reasons described below. the rate of change of the temperature in the parcel may be less than or more than the elr. when a parcel of air rises, it expands, because the pressure is lower at higher altitudes. as the air parcel expands, it pushes on the air around it, doing work ; but generally it does not gain heat in exchange from its environment, because its thermal conductivity is low ( such a process is called adiabatic ). since the parcel does work and gains no heat, it loses energy, and so its temperature decreases. ( the reverse, of course, will be true for a sinking parcel of air. ) since the heat exchanged is related to the entropy change by, the equation governing the temperature as a function of height for a thoroughly mixed atmosphere is if the air contains water vapor, then cooling of the air can cause the water to condense, and the behavior is no longer that of an ideal gas. if the air is at the saturated vapor pressure, then the rate at which temperature drops with height is called the saturated adiabatic lapse rate. more generally, the actual rate at which the temperature drops with altitude is called the environmental lapse rate. in the troposphere, the average environmental lapse rate is a drop of about 6. 5 °c for every 1 km ( 1, 000 meters ) in increased height. the environmental lapse rate ( the actual rate at which temperature drops with height, ) is not usually equal to the adiabatic lapse rate ( or correspondingly, ). if the upper air is warmer than predicted by the adiabatic lapse rate ( ), then when a parcel of air rises and expands, it will arrive at the new height at a lower temperature than its surroundings. in this case, the air parcel is denser than its surroundings, so it sinks back to its original height, and the air is stable against being lifted. if, on the contrary, the upper air is cooler than


lower temperature than its surroundings. in this case, the air parcel is denser than its surroundings, so it sinks back to its original height, and the air is stable against being lifted. if, on the contrary, the upper air is cooler than predicted by the adiabatic lapse rate, then when the air parcel rises to its new height it will have a higher temperature and a lower density than its surroundings, and will continue to accelerate upward. temperatures decrease at middle latitudes from an average of 15°c at sea level to about - 55°c at the top of the tropopause. at the poles, the troposphere is thinner and the temperature only decreases to - 45°c, while at the equator the temperature at the top of the troposphere can reach - 75°c. the tropopause is the boundary region between the troposphere and the stratosphere. measuring the temperature change with height through the troposphere and the stratosphere identifies the location of the tropopause. in the troposphere, temperature decreases with altitude. in the stratosphere, however, the temperature remains constant for a while and then increases with altitude. the region of the atmosphere where the lapse rate changes from positive ( in the troposphere ) to negative ( in the stratosphere ), is defined as the tropopause. thus, the tropopause is an inversion layer, and there is little mixing between the two layers of the atmosphere. atmospheric flow the flow of the atmosphere generally moves in a west to east direction. this however can often become interrupted, creating a more north to south or south to north flow. these scenarios are often described in meteorology as zonal or meridional. these terms, however, tend to be used in reference to localised areas of atmosphere ( at a synoptic scale ). a fuller explanation of the flow of atmosphere around the earth as a whole can be found in the three - cell model. zonal flow a zonal flow regime is the meteorological term meaning that the general flow pattern is west to east along the earth ' s latitude lines, with weak shortwaves embedded in the flow. the use of the word " zone " refers to the flow being along the earth ' s latitudinal " zones ". this pattern can buckle and thus become a meridional flow. meridional flow when the zonal flow buckles, the atmosphere can flow in a more longitudinal ( or meridi


the earth ' s latitudinal " zones ". this pattern can buckle and thus become a meridional flow. meridional flow when the zonal flow buckles, the atmosphere can flow in a more longitudinal ( or meridional ) direction, and thus the term " meridional flow " arises. meridional flow patterns feature strong, amplified troughs and ridges, with more north - south flow in the general pattern than west - to - east flow. three - cell model the three cells model attempts to describe the actual flow of the earth ' s atmosphere as a whole. it divides the earth into the tropical ( hadley cell ), mid latitude ( ferrel cell ), and polar ( polar cell ) regions, dealing with energy flow and global circulation. its fundamental principle is that of balance - the energy that the earth absorbs from the sun each year is equal to that which it loses back into space, but this however is not a balance precisely maintained in each latitude due to the varying strength of the sun in each " cell " resulting from the tilt of the earth ' s axis in relation to its orbit. it demonstrates that a pattern emerges to mirror that of the ocean - the tropics do not continue to get warmer because the atmosphere transports warm air poleward and cold air equatorward, the effect of which appears to be that of heat and moisture distribution around the planet. synoptic scale observations and concepts forcing is a term used by meteorologists to describe the situation where a change or an event in one part of the atmosphere causes a strengthening change in another part of the atmosphere. it is usually used to describe connections between upper, middle or lower levels ( such as upper - level divergence causing lower level convergence in cyclone formation ), but can sometimes also be used to describe such connections over distance rather than height alone. in some respects, tele - connections could be considered a type of forcing. divergence and convergence an area of convergence is one in which the total mass of air is increasing with time, resulting in an increase in pressure at locations below the convergence level ( recall that atmospheric pressure is just the total weight of air above a given point ). divergence is the opposite of convergence - an area where the total mass of air is decreasing with time, resulting in falling pressure in regions below the area of divergence. where divergence is occurring in the upper atmosphere, there will be air coming in to try to balance the net loss of mass ( this is called the principle of mass conservation )


time, resulting in falling pressure in regions below the area of divergence. where divergence is occurring in the upper atmosphere, there will be air coming in to try to balance the net loss of mass ( this is called the principle of mass conservation ), and there is a resulting upward motion ( positive vertical velocity ). another way to state this is to say that regions of upper air divergence are conducive to lower level convergence, cyclone formation, and positive vertical velocity. therefore, identifying regions of upper air divergence is an important step in forecasting the formation of a surface low pressure area. - " iss022 - e - 062672 caption ". nasa. retrieved 21 september 2012. - mcgraw - hill concise encyclopedia of science & technology. ( 1984 ). troposhere. " it contains about four - fifths of the mass of the whole atmosphere. " - danielson, levin, and abrams, meteorology, mcgraw hill, 2003 - landau and lifshitz, fluid mechanics, pergamon, 1979 - landau and lifshitz, statistical physics part 1, pergamon, 1980 - kittel and kroemer, thermal physics, freeman, 1980 ; chapter 6, problem 11 - " american meteorological society glossary - zonal flow ". allen press inc. june 2000. retrieved 2006 - 10 - 03. - " american meteorological society glossary - meridional flow ". allen press inc. june 2000. retrieved 2006 - 10 - 03. - " meteorology - msn encarta, " energy flow and global circulation " ". encarta. msn. com. archived from the original on 2009 - 10 - 31. retrieved 2006 - 10 - 13. | look up troposphere in wiktionary, the free dictionary. | - composition of the atmosphere, from the university of tennessee physics dept. - chemical reactions in the atmosphere - http : / / encarta. msn. com / encyclopedia _ 761571037 _ 3 / meteorology. html # s12 ( archived 2009 - 10 - 31 )


case study is often defined in different ways, reflecting evolving practice. what is important then is to define the concept for yourself, and explain to your audience how you are using the term. - a research approach in which one or few instances of a phenomenon are studied in depth ( given, 2008 ). - an empirical inquiry that investigates a contemporary phenomenon within its real - life context ; when the boundaries between phenomenon and context are not clearly evident ; and in which multiple sources of evidence are used. ( yin, 1984 ) case study involves a detailed in depth analysis of an organisation, person, a group, an event, allowing an understanding of complex phenomena, such as organisations. a case study generally involves looking at a single case ( which already exists ), an object of study which is easily identified and separated ( a bounded system ) from other similar objects e. g. an organization, a place, an illness in one patient. case study is a useful methodology for focussing on relationships connecting everyday practices in natural settings, placing attention on a local situation ( stake, 2006 ). the case study is useful to investigate an issue in depth and ‘ provide an explanation that can cope with the complexity and subtlety of real of life situation ’ ( denscombe, 2010, p55 ). research questions revolve around ‘ how? ’ or ‘ why? ’ and may be explanatory, exploratory or descriptive in nature ( yin, 2003 ). case study can be used to develop theory. yin ( 2003, p 1 ) notes that a case study is a way to ‘ contribute to our knowledge of individual, group, organisational, social, political and related phenomena ’ case study can be used to test theory : what is it supposed to do and does it do that? case studies can be used to trace a process, developing an understanding and then test it ( bennett, andrew ) data collection case studies generally use a combination of data collection methods. multiple case studies in multiple cases, research single cases are meaningful in relation to the other cases cited. multiple case study research needs to use cases that are similar in some ways. the cases become " members of a group or examples of a phenomenon " ( stake, 2006, p. 6 ). this allows examination of what is similar and dissimilar about the cases. the researcher is looking for patterns and uniqueness, particulars and generalisations in the cases developed. references and resources denscombe, martyn ( 2010 ) ( 4th ed ). the good research guide


dissimilar about the cases. the researcher is looking for patterns and uniqueness, particulars and generalisations in the cases developed. references and resources denscombe, martyn ( 2010 ) ( 4th ed ). the good research guide for small scale social research projects. maidenhead : open university pres mcgraw hill dufour, s. & foutin, v., ‘ annotated bibliography of case study method ’, current sociology vol. 40 / 1, 1992, pp. 166 - 181. fidel, r. ( 1984 ). ‘ the case study method : a case study ’, library and information science research vol. 6 / 3, pp. 273 - 288. garson, g. d. ( 2008 ). case studies, available from http : / / faculty. chass. ncsu. edu / garson / pa765 / cases. htm gerring, j. ( 2007 ). case study research : principles and practices, cambridge university press, cambridge. gilbertson, d. w. & stone, r. j. ( 1985 ) ( 2nd ed ). human resources management : cases and readings. sydney : mcgraw - hill, 1985. giving, l. m. ( 2008 ) ( ed. ), the sage encyclopedia of qualitative research methods, los angeles : sage. hossain, dewan mahboob ( 2009 ). ' case study research ' social science research network http : / / ssrn. com / abstract = 1444863 marshall, c. & rossman, g. b. ( 2006 ) ( 4th ed ). designing qualitative research, thousand oaks : sage. merriam s. ( 1998 ). qualitative research and case study application in education. san francisco : jossey bass. ragin, c. c. & becker, h. s. ( 1992 ), what is a case? exploring the foundations of social enquiry, cambridge university press, cambridge. sadler, d. royce ( 1985 ). ‘ evaluation, policy analysis and multiple case studies : aspects of focus and sampling ’, educational evaluation and policy analysis, vol. 7 / 2, pp. 143 - 149. simons ( 2009 ). case study research in practice. london : sage stake, r. e. ( 1995 ). the art of case study research. thousand oaks : sage publications. stake, r. e. ( 2006 ), multiple case study analysis, new york & london :


we need another and a wiser and perhaps a more mystical concept of wild animals. remote from universal nature, and living by complicated artifice, man in civilization surveys the creatures through the glass of his knowledge and sees thereby a feather magnified and the whole image in distortion. we patronize them for their incompleteness, for their tragic fate for having taken a form so far below ourselves. and therein we err, greatly err. for the animal shall not be measured by man. in a world older and more complete than ours they move finished and complete, gifted with extensions of the senses we have lost or never attained, living by voices we shall never hear. they are not brethren, they are not underlings ; they are other nations, caught with ourselves in the net of life and time, fellow prisoners of the splendour and the travail of the earth. - henry beston, the outermost house, as cited by karsten heuer in being caribou : five months on foot with an arctic herd, p. 10 in the “ complicated artifice ” of immured, urban life, i often experience the living world of the animals, plants and minerals in the tundras, deserts, mountains, rivers, lakes, forests, caves and oceans like a ghost - appendage, like a part of me that i can ’ t shake the awareness of, though i live in a fast - moving, technologically driven human ‘ nation ’ that has severed itself from these other nations both in habitat and in consciousness. the influential philosophical writings of the ancient greeks, particularly of aristotle, conveyed down to us through innumerable refracted lenses in the post - classical tradition the notion that human beings are superior to the animal kingdom as a result of their unique possession of ‘ logos ’, or the capacity to reason. aristotle took this analogy even further, to suggest that just as domestic animals ’ benefit ’ from their domination by human beings, so do women and slaves ‘ benefit ’ by being ruled by free men. aristotle ’ s writings supplied the european and early american slave - traders and slave - owners of the 17th - 19th centuries with canonical arguments for racialized, chattel slavery. what comes of the persistent human belief in separation? our human history is littered with exemplum upon exemplum of the tragic consequences of this belief. mindfulness practices provide an antidote. they help us to reestablish connections with each other and with other nations. they help us to really feel


the natural objects that i propose to consider are broadly those physical objects which are studied and referred to by science and by a common sense view, informed by science, of the world. natural objects are, philosophically speaking, individuals ; they are involved as units in dynamic, causal processes. i shall draw a distinction between natural objects and the abstract objects of mathematics, in particular set theory. natural objects encompass atoms and molecules ; cells and organisms, including you and me ; the objects of everyday life such as chairs and automobiles ; nations, continents, ecosystems, mountain ranges, geological faults ; planets, stars and galaxies. each natural object, when regarded internally, is a dynamic system with various interacting parts and components ( some of which may be natural objects in their own right ) ; when regarded externally, a natural object acts as a unit with respect to a larger system or systems ( which may again be natural objects ) of which the given object forms a part or component. it is sometimes argued that objects such as atoms or galaxies are theoretical constructs, as much so as mathematical objects ( or even, according to some, more so ). it is true that any reference to an object rests on epistemological assumptions. the approach here will be not to belittle these important epistemological questions but to leave them aside, and accept as a working assumption the practical viewpoint of people who are dealing with the world : that natural objects exist, act, and are acted upon, independently of the observer - - although any description of them or of their actions is dependent on the describer. scientific theories refer to natural objects as well as to abstractions of them ; they also refer to and quantify over other entities, in particular, the real numbers, points in space, time, and other mathematical spaces such as vector spaces, hilbert space, etc. - - these are abstract objects which are not necessarily abstractions of any natural objects. thus the ontology of natural objects may be said to be more restrictive than, say, a quinesque one. my point, however, is again not to dispute the validity of this or that ontology, but rather to describe a level of existence. no judgment will be presumed about the question of what ontological commitment should be made to abstract objects : rather, our focus of attention will be elsewhere. in the examples above and in what follows, i concentrate on physical objects. i do not mean to rule out psychic or spiritual or intellectual objects. you and i, as objects, have these aspects ; french society


our focus of attention will be elsewhere. in the examples above and in what follows, i concentrate on physical objects. i do not mean to rule out psychic or spiritual or intellectual objects. you and i, as objects, have these aspects ; french society, indian classical music, the theory of natural selection, king lear, king lear, the collective unconscious may all be regarded as natural objects. their ties to physical existence ( in the sense of matter and energy ) or to extensional ( spatial ) existence are various, and there is scope for varied theories about their ontological status ; i tend to follow nicolai hartmann ( 1949 ) in assigning to spiritual and psychic strata " categorial dependence " on the strata of physical existence in spaces : thus these objects are tied, however indirectly, to the physical level of existence. what i have to say will apply to such objects, in so far as they are acknowledged to exist ; and even to purely spiritual or psychic objects not tied to the physical level of existence at all, if they are admitted to exist. but i shall keep largely to physical and biological examples as being less problematic. this will also insulate the discussion from problems of consciousness and free will which inevitably come up but are not my concern here. thus the natural objects to be considered here may correspond more or less to the " natural bodies " of francis bacon : " toward the effecting of works, all that man can do is to put together or put asunder natural bodies. " ( bacon 1620, 39 ) an interesting example of a natural object is a hurricane. it is an open system, exchanging matter, energy and information with its environment, and acting as a whole. it is certainly accorded the status of an individual, in everyday language and in meteorology, even to the extent of being given a proper name ( such as floyd, mitch, zeb or babs ). it cannot be precisely identified with any set of atoms or molecules ; and any boundary in space or time that you try to draw for the hurricane will be arbitrary. meteorologists will draw such a boundary - - say, the point in time when a tropical storm is upgraded to a hurricane - - according to conventions about energy content and wind speeds, but the passing of a boundary is merely the employment of a convenient yardstick and is not supposed to have absolute significance. natural objects may usefully be described as systems. von bertalanffy ( 1968 ) defines a system as " a complex of interacting elements " ( although von bertalanffy '


a convenient yardstick and is not supposed to have absolute significance. natural objects may usefully be described as systems. von bertalanffy ( 1968 ) defines a system as " a complex of interacting elements " ( although von bertalanffy ' s elements are not to be equated with elements in the set - theoretic sense, and to avoid confusion i use " components " ). he goes on to study systems defined in terms of partial differential equations. mesarovic and takahara ( 1975 ) develop a more general, set - based concept of system. they are able to define such notions as cascading, feedback, and open systems. natural objects can be named, or they can be defined by ostension. often, naming and pointing will be essentially the only ways to refer unambiguously to a particular object. 2. natural and abstract objects the words " a logic " of the title are intended to suggest the aim of depicting how we reason or infer about natural objects. set theory, as a foundation for mathematics, is a way of doing this for abstract objects. before examining natural objects more closely, i wish to compare them with abstract objects - - which i shall identify, for concision, with sets - - in order to bring out some properties relevant to both. cantor ( 1895 ) introduced the concept of set as " any comprehension into a whole m of definite and separate objects m of our intuition or our thought ", and the modern development of set theory has retained the spirit of cantor ' s conception, in particular through the fundamental role of the comprehension axiom. even in the limited form necessary to avoid the paradoxes, comprehension formalizes the grouping together of objects with like properties into a single entity. the objects - - sets, classes - - of set theory are abstractions, the product of our mental processes ( " our intuition or our thought " ) which impose an organization on the world we perceive. except under a naive platonist interpretation, sets are not required to have an autonomous existence outside the formal system that creates them : that is to say, outside the language of the observer. ( the same goes for all other mathematical objects, including categories. ) thus set theory may be said to be a part of epistemology, the study of our knowledge of the world. following a hint of graham c. d. griffiths ( 1974, 87 ) i wish to contrast this with ontology, the study of what things exist, independently of any observer. from a scientific perspective, objects such


of our knowledge of the world. following a hint of graham c. d. griffiths ( 1974, 87 ) i wish to contrast this with ontology, the study of what things exist, independently of any observer. from a scientific perspective, objects such as atoms, molecules, organisms ( including persons ), stars, galaxies may be said to have an objective individual existence - - although there are borderline cases where the object ' s existence as a separate individual may be questionable, and the individuality of, say, a quark is of a very different nature from yours or mine. on the other hand, sets of objects, such as the set of all stars, or an arbitrary collection of, say, 100 people chosen at random, can exist as individuals only in an abstract sense ( though the former example may be viewed as a natural kind ). in addition, the " definite and separate " character of the elements of a set is not always found in nature where boundaries are generally ill - defined and separation may be relative and time - dependent. natural objects interact, are born of others, and die. to bring out how natural objects in general differ from sets, let me pause to consider the nature of one particular object, myself, whose autonomy and continuity i feel so clearly ( but proceeding in a different direction from descartes ). can i precisely be identified with a set? what about the set of cells that contain my unique dna? this set provides a good approximation to my physical extent, but there are many problems with identifying " me " with this set : i am not trying to attack set theory as such. i simply wish to note that the common mode of talking about the world leaves philosophical doubts aside and names natural objects ; that the language of science is full of them ( as well as of abstract objects ) ; and that set - theoretic language does not capture the nature of natural objects, as of course it was never intended to. it therefore seems worthwhile to try and develop a theory of natural objects. as jody azzouni puts it ( 1994, 4 ), mathematical objects are metaphysically inert. natural objects, by contrast, interact intensively with the rest of the world, and this interaction in fact cannot be separated from their nature. but great care will be needed because once a mathematical framework for referring to these objects has been established, the referents themselves will be mathematical objects. rigorous separation of levels of discourse will be necessary - - but this is nothing new in logic and metamathematics. sets are


needed because once a mathematical framework for referring to these objects has been established, the referents themselves will be mathematical objects. rigorous separation of levels of discourse will be necessary - - but this is nothing new in logic and metamathematics. sets are abstracted ( from the latin : drawn away ) from direct physical experience. a common example frequently seen in expositions of elementary ( naive ) set theory illustrates the abstract nature of the set concept by explaining how a collection of disparate objects can be grouped together into a set merely by enumerating them or by specifying a common property - - no matter how incongruous and varied their natures or how widely separated they are in space and time. this kind of construction is counter - intuitive to a student who is not accustomed to thinking in terms of abstractions ; the natural objects one is used to dealing with in less abstract contexts do not have these properties. even the pair set axiom does not hold, in general, for natural objects. a pair of objects is not, usually, a single object ( although in special cases one will consider certain pairs as a unit ; for example a married couple is an object in legal considerations ). the same goes for other elementary set - theoretic constructions such as unions and intersections. the distinction between individuals and classes is relevant here. ( some philosophers talk of natural kinds ; others oppose individuals to " sets ". ) this distinction, which goes back to plato and aristotle, was blurred by cantor : his sets are both individuals and classes. indeed, the principle of comprehension is a formalization of the notion that a class of objects is defined, as an individual, by a common property that they share. the subsequent development of set theory reinstated the individual / class distinction in a different form with sets and proper classes ; this happened as early as cantor ( 1899 ). different versions of modern set theory ( zermelo - fraenkel, von neumann - bernays - godel ) vary in the ontological status accorded to proper classes, as do different interpretations of the formalisms. however, the basic point here is that sets are essentially collections ( " multiplicities " - - cantor ) treated as individuals. a natural object is never merely a collection ; the interaction of its components is an essential part of its individuality. it is perhaps of interest to note that ernst zermelo, in his fundamental paper ( 1908 ) on axiomatizing set theory, seemed to be open - minded about whether all objects are sets : "