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Modern_Robotics_All_Videos
Modern_Robotics_Chapter_411_Product_of_Exponentials_Formula_in_the_Space_Frame.txt
Chapter 4 addresses the forward kinematics of open-chain robots, as illustrated in this video of a robot with 6 revolute joints. We define a frame {s} fixed in space, often at the base of the robot, and a frame {b} at the end-effector of the robot arm. If we command the robot to move, the {b}-frame moves. The forward k...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_5_Velocity_Kinematics_and_Statics.txt
In the last chapter, we studied the forward kinematics, relating the joint positions to the end-effector configuration, T of theta. In this chapter, we study the relationship between joint velocities and the end-effector velocity. Usually we represent the configuration of the end-effector as a transformation matrix and...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_1211_FirstOrder_Analysis_of_a_Single_Contact.txt
Contact kinematics is the study of the motion constraints due to contact between bodies. For example, if these two bodies are in contact, I could ask what motions of the bodies will keep them in contact and what motions will cause breaking contact. Let's say that q_1 and q_2 are coordinate representations of the rigid-...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_113_Motion_Control_with_Velocity_Inputs_Part_3_of_3.txt
For the case where the controller commands joint velocities, in the previous video we derived a feedforward plus PI feedback controller when the desired motion is expressed in joint space. Now consider the case where the desired motion is expressed as X_d, the desired SE(3) configuration of the end-effector as a functi...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_11221_FirstOrder_Error_Dynamics.txt
Let's continue to assume our error dynamics can be expressed as a linear ordinary differential equation, such as this second-order differential equation from the previous video. Let's set the mass equal to zero, giving us this first-order differential equation, which says that the force due to the spring and the force ...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_82_Dynamics_of_a_Single_Rigid_Body_Part_2_of_2.txt
In the previous video, we derived these equations of motion for a rigid body, for wrenches, twists, and accelerations defined in a body frame {b}. In this video, we express these equations in a form analogous to the equations of motion for a body that only rotates. To do this, we define the 6-by-6 spatial inertia matri...
Modern_Robotics_All_Videos
Modern_Robotics_Introduction_to_the_Lightboard.txt
Welcome to the video supplements for the book Modern Robotics. My name is Kevin Lynch, and my co-author is Frank Park. We're shooting these videos using the Lightboard, a tool for video creation invented by Professor Michael Peshkin here at Northwestern. In front of me is a pane of glass that I can write on. On the oth...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_113_Motion_Control_with_Velocity_Inputs_Part_2_of_3.txt
In the previous video we saw that, for the task of tracking a trajectory with a constant velocity, a proportional controller results in nonzero steady-state error c over K_p. To fix this, let's augment the P controller with another term that is proportional to the integral of the error over time. K_i is called the inte...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_1333_Motion_Planning_for_Nonholonomic_Mobile_Robots.txt
Most path planners in Chapter 10 can be applied to omnidirectional mobile robots, because of their ability to move in any direction. The same is not true for nonholonomic mobile robots, due to their motion constraints. In this video we'll look at optimal motion plans for car-like robots in an obstacle-free plane, as we...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_52_Statics_of_Open_Chains.txt
Here you can see a 6R robot with a frame {b} at the hand. Imagine that the joints are moving according to a trajectory theta of t. The changing joint angles theta as a function of time move the hand along the path shown in yellow. The hand is moving in free space, so it is applying no forces to the environment. In Chap...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_54_Manipulability.txt
A robot configuration is either singular or it's not. But even if a configuration is nonsingular, it still may be close to being singular. The manipulability ellipsoid we saw in the first video of this chapter is one way to visualize how close a robot is to being singular. For this 2_R robot, a circle of velocities in ...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_62_Numerical_Inverse_Kinematics_Part_1_of_2.txt
The forward kinematics maps the joint vector theta to the transformation matrix representing the configuration of the end-effector. For simplicity, we will start instead with a coordinate-based forward kinematics, where f of theta is a minimal set of coordinates describing the end-effector configuration. Then the inver...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_323_Exponential_Coordinates_of_Rotation_Part_1_of_2.txt
Any orientation can be achieved from an initial orientation aligned with the space frame by rotating about some unit axis by a particular angle. We call the unit axis omega-hat and the rotation distance theta. If we multiply these two together, we get the 3-vector omega-hat theta. This is a 3-parameter representation o...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_332_Twists_Part_1_of_2.txt
As we learned in the last video, a transformation matrix T can be used to represent the configuration of the body frame {b} relative to the space frame {s}. Now we need to represent the velocity of the body frame. Just as the time derivative of a rotation matrix was not our representation of angular velocity, the time ...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_34_Wrenches.txt
A robot hand is holding this apple in gravity, and the robot is equipped with a force-torque sensor at its wrist. It measures forces and torques in the frame {f}. If we know the mass of the apple, the direction of gravity, and the location of the apple in the hand, what are the forces and torques measured by the sensor...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_135_Mobile_Manipulation.txt
A mobile manipulator consists of a mobile base outfitted with one or more robot arms, such as this omnidirectional base with a 5-joint arm. To control the motion of the end-effector, we can control both the wheels and the arm joints. Since the arm motion is typically more precise than the motion of the base, a common w...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_111_Control_System_Overview.txt
Every robot has a controller, which continuously reads from sensors like motor encoders, force sensors, or even vision or depth sensors, and updates the actuator commands so as to achieve the desired robot behavior. Examples of control objectives include motion control, as when a robot arm moves along a specified traje...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_232_Configuration_Space_Representation.txt
To represent a C-space using real numbers, we have to make some arbitrary choices. For example, to represent points on a plane, we choose a point in the space as the origin, and two orthogonal coordinate axes. With that choice, we can represent any point as a list of two coordinates, x-y. Of course our representation o...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_1224_Duality_of_Force_and_Motion_Freedoms.txt
To analyze a manipulation task involving contacts, we combine our modeling of contact kinematics with the Coulomb friction model. At any instant, a contact could be breaking, sliding, or rolling, and each of these cases implies different constraints on the feasible motions and forces at the contact. Importantly, though...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_321_Rotation_Matrices_Part_1_of_2.txt
We begin our study of the representation of the configuration of a rigid body by focusing on orientation only. The approach to representing the full configuration of a rigid body is analogous. Consider two frames, a space frame {s} and a body frame {b}. They are shown at different locations, but we are focusing on thei...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_134_Odometry.txt
Odometry is the process of estimating the chassis configuration from wheel motions, essentially integrating the effect of the wheel velocities. Since wheel-rotation sensing is available on all mobile robots, odometry is convenient. Odometry errors tend to accumulate over time, though, due to slipping or skidding of the...
Modern_Robotics_All_Videos
Modern_Robotics_Chapters_91_and_92_PointtoPoint_Trajectories_Part_2_of_2.txt
In the previous video, we learned that a trajectory can be represented as theta-of-s-of-t. We also found expressions for simple paths theta-of-s. In this video, we study time scalings s-of-t that turn a path into a trajectory. One simple time scaling is a third-order polynomial time scaling, where s is a cubic function...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_86_Dynamics_in_the_Task_Space.txt
Until now, we have been focusing on robot dynamics expressed in the space of joint motions and joint forces and torques. We could equivalently formulate the dynamics in the task space, that is, the space of end-effector motions and end-effector wrenches. We assume that the end-effector twist V equals the Jacobian times...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_231_Configuration_Space_Topology.txt
In addition to the number of degrees of freedom, another important property of a configuration space is its shape, or topology. Consider a plane and the surface of a sphere, for example. Both of these spaces have two dimensions, but their shape is quite different: the sphere wraps around in a way that the plane does no...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_332_Twists_Part_2_of_2.txt
In the last video, we learned that rigid-body velocities can be represented as a 6-vector twist. The twist can be represented in any arbitrary frame; for example, the twist could be represented as V_a in frame {a} or as V_b in frame {b}. If we want to change the frame of representation of a twist, it is tempting to try...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_113_Motion_Control_with_Velocity_Inputs_Part_1_of_3.txt
When we model a robot, we usually assume that we have control of the forces and torques at the joints, and the resulting motion of the robot is determined by its dynamics. This is the model we will use starting in Chapter 11.4. It's simpler, however, and occasionally even more appropriate, to ignore the dynamics and as...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_1216_Planar_Graphical_Methods_Part_2_of_2.txt
In the previous video we saw that a cone of planar twists can be represented as a region of centers of rotation. In this video, we'll learn a simple rotation center representation for the feasible twist cone of a planar body subject to multiple stationary contacts. This figure shows a stationary triangle contacting a p...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_53_Singularities.txt
We've seen two major uses of Jacobian matrices: converting a set of joint velocities theta-dot to an end-effector twist V and converting an end-effector wrench F to a set of joint forces and torques tau. The twists and wrenches can be expressed in the space frame {s} or the end-effector frame {b}. The Jacobian is a 6 b...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_24_Configuration_and_Velocity_Constraints.txt
For robots with links and joints forming closed loops, it is often easier to find an implicit representation of the C-space rather than an explicit parametrization. Consider the 4-bar closed chain shown here. Grubler's formula tells us the 4-bar has one degree of freedom, so it should be possible to parametrize the C-s...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_1023_Graphs_and_Trees.txt
Although the C-space of a robot is a continuous space, in motion planning we typically discretize it in some way. For example, this image shows a mobile robot in a maze. We could represent the free space of this maze by sampling some free configurations and drawing lines between configurations that can reach each other...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_1221_Friction.txt
Forces transmitted through a contact can include both normal forces as well as tangential forces, due to friction. To understand the friction force, imagine pulling a block with a spring. To cancel the downward gravitational force on the block, the floor pushes upward with a normal force f_n. The force applied by the s...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_132_Omnidirectional_Wheeled_Mobile_Robots_Part_2_of_2.txt
Recall that the configuration of the chassis of a wheeled robot can be written q = (phi,x,y), the heading direction and position of the chassis. In the previous video, we derived the relationship u equals H-of-phi times q-dot, where u is the vector of wheel speeds. For any properly constructed omnidirectional robot, an...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_1332_Controllability_of_Wheeled_Mobile_Robots_Part_1_of_4.txt
Controllability refers to the ability to drive a system from one state to another. For a kinematic model of a wheeled mobile robot, the state is just the configuration q of the chassis, with components phi, x, y. Consider an omnidirectional wheeled mobile robot with a goal configuration q_goal. A simple controller to d...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_21_Degrees_of_Freedom_of_a_Rigid_Body.txt
The most fundamental question you can ask about a robot is, "Where is it?" The answer to this question is the robot's configuration, which is a specification of the positions of all the points of the robot. In this book, robots are constructed of rigid bodies, like this one. We often call these rigid bodies links. Thes...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_116_Hybrid_MotionForce_Control.txt
In the previous video I described force control, where the robot is capable of generating an end-effector wrench in any direction, as if it is buried in concrete. This is rarely the case, though; typically there are some directions the end-effector can move freely. In this video, we assume that the robot interacts with...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_94_TimeOptimal_Time_Scaling_Part_1_of_3.txt
In the next few videos, we consider the following problem: Given a desired path theta-of-s, find the time-optimal time scaling along this path, considering the dynamics of the robot and torque limits at the robot joints. Minimum-time motions can be used to maximize the productivity of a robot. You could imagine trying ...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_322_Angular_Velocities.txt
Let's say that R is the rotation matrix of a frame {b} relative to a frame {s}. A simple idea is to define the rate of rotation of {b}, which is also called the angular velocity, to be R-dot, the time rate of change of R. But this has 9 variables, and we should be able to find a good representation of angular velocity ...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_1122_Linear_Error_Dynamics.txt
The error dynamics describes the combined dynamics of the robot and the controller in response to a reference input. As we saw in the last video, an error response could look something like this. Here the error response has zero steady-state error and lots of overshoot and oscillation. This plot also happens to be the ...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_7_Kinematics_of_Closed_Chains.txt
In Chapters 4, 5, and 6, we studied the forward kinematics, velocity kinematics and statics, and inverse kinematics of open-chain robots. In Chapter 7, and in this single video, I am going to cover all of these topics for closed-chain robots, without going into great detail. Kinematics and statics are generally more co...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_22_Degrees_of_Freedom_of_a_Robot.txt
In the previous video, we learned that the number of degrees of freedom of a robot is equal to the total number of freedoms of the rigid bodies minus the number of constraints on their motion. The constraints on motion often come from joints. The most common type of joint is the revolute joint. It places 5 constraints ...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_87_Constrained_Dynamics.txt
We've been discussing the dynamics of open-chain robots. If the robot's motion is subject to constraints, however, like nonholonomic constraints due to wheels or the loop-closure constraints of parallel robots, such as the Stewart platform, we have to add forces that enforce the constraints. Another example of a robot ...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_321_Rotation_Matrices_Part_2_of_2.txt
There are three common uses of a rotation matrix: The first is to represent an orientation. The second is to change the frame of reference of a vector or frame. And the third is to rotate a vector or frame. To demonstrate these, I will use these three coordinate frames, representing the same space with different orient...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_83_NewtonEuler_Inverse_Dynamics.txt
In this video we use the inverse dynamics of a rigid body that we derived in the last video to derive the Newton-Euler inverse dynamics algorithm for an open-chain robot. Consider an n-link robot with an end-effector. Each link is a rigid body, and the center of mass of each link is shown. We assign frames {1} through ...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_12_Grasping_and_Manipulation.txt
In this chapter we focus on robot manipulation. One example of manipulation is grasping and carrying, and questions we could pose include: "How many fingers are needed to grasp the object firmly?" and "Where should the fingertips be placed?" We answer these questions in this chapter. Grasping is attractive because, onc...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_81_Lagrangian_Formulation_of_Dynamics_Part_1_of_2.txt
In Chapter 8, we study the dynamics of open-chain robots. For example, the forward dynamics problem is to calculate the joint accelerations theta-double-dot given the current joint positions theta, the joint velocities theta-dot, and the forces and torques tau applied at each joint. The forward dynamics is useful for s...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_333_Exponential_Coordinates_of_RigidBody_Motion.txt
In the previous videos, we learned that any instantaneous velocity of a rigid body can be represented as a twist, defined by a speed theta-dot rotating about, or translating along, a screw axis S. In this video, we integrate the vector differential equation describing the motion of a frame twisting along a constant scr...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_1121_Error_Response.txt
In the previous video, we saw that the controller compares the desired behavior to the actual behavior to produce its control signals. If the control objective is motion control, then the desired behavior is given by the desired motion, theta_d of t. This is also called the reference input. The actual motion is theta o...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_511_Space_Jacobian.txt
In the previous video, the robot's end-effector velocity v_tip was the time derivative of a minimum set of coordinates describing the end-effector's configuration. The Jacobian J maps the joint velocities to v_tip. For this 2R robot, the Jacobian has two columns, one for each joint, which we call J_1 and J_2. Each colu...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_104_Grid_Methods_for_Motion_Planning.txt
In this video we'll plan motions on a graph derived from a grid on the C-space. If the C-space has n-dimensions, we can subdivide each dimension into k intervals, creating a total of k-to-the-n grid cells. Each cell is represented in the graph by a single node, representing the configuration at the center of the cell. ...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_123_Transport_of_an_Assembly.txt
Here's a planar assembly of blocks on a table. We'd like to know if this assembly will stand or fall. To test if standing is a possible solution, for each block we can write a vector static balance equation, where F_ext is the external force acting on the block, in this case gravity, and the contact wrenches on each bl...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_123_Manipulation_and_the_MeterStick_Trick.txt
This is the equation of motion for a single rigid body subject to frictional contacts. The right-hand side is the rigid-body dynamics we derived in Chapter 8. F_contact is the total wrench from all of the contacts, and F_ext is the wrench due to gravity or other forces. The procedure to analyze a rigid-body mechanics p...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_94_TimeOptimal_Time_Scaling_Part_3_of_3.txt
In the previous video we learned a graphical interpretation of the time-optimal time scaling problem. Basically, we try to keep the speed s-dot as high as possible while remaining within the motion cone dictated by the robot's actuators. In some cases, the time-optimal solution is given by a bang-bang trajectory, where...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_1024_Graph_Search.txt
It is common to represent the free C-space as a graph, where the nodes represent configurations and the edges represent free paths between the configurations. Once we have a graph, we need to search it to find a path between the start configuration and a goal configuration. The graph shown here has six nodes. Let's ima...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_106_Virtual_Potential_Fields.txt
The motion planners we have seen so far are based on offline search. In this video we introduce a reactive real-time controller based on virtual potential fields defined on the robot's C-space. One potential field pulls the robot's configuration toward the goal configuration, while obstacle potential fields repel the r...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_3_Introduction_to_RigidBody_Motions.txt
In Chapter 3, we learn representations of configurations, velocities, and forces that we'll use throughout the rest of the book. As discussed in the last chapter, we'll use implicit representations of configurations, considering the C-space as a surface embedded in a higher-dimensional space. In other words, our repres...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_115_Force_Control.txt
The goal of force control is to apply a desired end-effector wrench to the environment. Conceptually, you should imagine the end-effector is encased in a concrete wall, so that it can create a wrench in any direction. This is the equation of motion for a robot applying an end-effector wrench F_tip. Typically in force c...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_6_Inverse_Kinematics_of_Open_Chains.txt
In Chapter 4, we studied the forward kinematics of open chains: given the joint configuration theta, find the configuration of the end-effector frame {b} relative to the space frame {s}. In this chapter, we study the inverse kinematics problem: given a desired end-effector configuration, find joint positions that achie...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_101_Overview_of_Motion_Planning.txt
Chapter 10 focuses on robot motion planning, particularly in the case of obstacles in the environment. For example, in this video, a motion has been planned for the robot arm to move its end-effector from one frame to another, without hitting any obstacles in the environment. Since some versions of the path planning pr...
Modern_Robotics_All_Videos
Modern_Robotics_Chapter_85_Forward_Dynamics_of_Open_Chains.txt
In the last video we derived the recursive Newton-Euler inverse dynamics algorithm for open chains. In this video we address the forward dynamics, which solves for theta-double-dot given the joint forces and torques tau, the joint positions and velocities, and optionally an end-effector wrench F_tip. We can solve the f...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
6_Atoms_II.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high quality educational resources for free. | make a donation or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: Good afternoon. So...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
15_Atomlight_Interactions_IV.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high quality educational resources for free. To make a donation or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: OK. Well, the res...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
9_Atoms_V_and_Atoms_in_External_Fields_I.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high quality educational resources for free. To make a donation or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: Let's get started...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
25_Coherence_V.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high quality educational resources for free. To make a donation or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: So over the last ...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
3_Resonance_III.txt
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MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
2_Resonance_II.txt
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MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
24_Coherence_IV.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high quality educational resources for free. To make a donation or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: Good afternoon. S...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
21_Twophoton_Excitation_II_and_Coherence_I.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high quality educational resources for free. To make a donation or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: So, good afternoo...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
18_Line_Broadening_II.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high-quality educational resources for free. To make a donation or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: So we want to dis...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
1_Resonance_I.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high quality educational resources for free. To make a donation or view additional materials from 100s of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: Welcome to a new teac...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
17_Atomlight_Interactions_VI_and_Line_Broadening_I.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high-quality educational resources for free. To make a donation or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: Are we ready? So ...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
16_Atomlight_Interactions_V.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high quality educational resources for free. To make a donation or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: OK. Back to cavit...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
13_Atomlight_Interactions_II.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high quality educational resources for free. To make a donation or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: OK. So what we ar...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
19_Line_Broadening_III.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high-quality educational resources for free. To make a donation or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: Let's go back to ...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
14_Atomlight_Interactions_III.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high quality educational resources for free. To make a donation or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: Good afternoon. L...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
10_Atoms_in_External_Fields_II.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high-quality educational resources for free. To make a donation, or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: OK, let's get st...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
11_Atoms_in_External_Fields_III.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high quality educational resources for free. To make a donation or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: Good afternoon. S...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
22_Coherence_II.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high quality educational resources for free. To make a donation or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu PROFESSOR: Good afternoon. We...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
20_Line_Broadening_IV_and_Twophoton_Excitation_I.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high-quality educational resources for free. To make a donation or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: OK. Here is the m...
MIT_8421_Atomic_and_Optical_Physics_I_Spring_2014
5_Resonance_V_and_Atoms_I.txt
The following content is provided under a Creative Commons license. Your support will help MIT OpenCourseWare continue to offer high-quality educational resources for free. To make a donation, or view additional materials from hundreds of MIT courses, visit MIT OpenCourseWare at ocw.mit.edu. PROFESSOR: The last topic w...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_6_Training_Neural_Networks_I.txt
- Okay, let's get started. Okay, so today we're going to get into some of the details about how we train neural networks. So, some administrative details first. Assignment 1 is due today, Thursday, so 11:59 p.m. tonight on Canvas. We're also going to be releasing Assignment 2 today, and then your project proposals are ...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_7_Training_Neural_Networks_II.txt
- Okay, it's after 12, so I think we should get started. Today we're going to kind of pick up where we left off last time. Last time we talked about a lot of sort of tips and tricks involved in the nitty gritty details of training neural networks. Today we'll pick up where we left off, and talk about a lot more of thes...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_2_Image_Classification.txt
Okay, so welcome to lecture two of CS231N. On Tuesday we, just recall, we, sort of, gave you the big picture view of what is computer vision, what is the history, and a little bit of the overview of the class. And today, we're really going to dive in, for the first time, into the details. And we'll start to see, in muc...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_3_Loss_Functions_and_Optimization.txt
- Okay so welcome to CS 231N Lecture three. Today we're going to talk about loss functions and optimization but as usual, before we get to the main content of the lecture, there's a couple administrative things to talk about. So the first thing is that assignment one has been released. You can find the link up on the w...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_14_Deep_Reinforcement_Learning.txt
- Okay let's get started. Alright, so welcome to lecture 14, and today we'll be talking about reinforcement learning. So some administrative details first, update on grades. Midterm grades were released last night, so see Piazza for more information and statistics about that. And we also have A2 and milestone grades sc...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_10_Recurrent_Neural_Networks.txt
- Okay. Can everyone hear me? Okay. Sorry for the delay. I had a bit of technical difficulty. Today was the first time I was trying to use my new touch bar Mac book pro for presenting, and none of the adapters are working. So, I had to switch laptops at the last minute. So, thanks. Sorry about that. So, today is lectur...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_9_CNN_Architectures.txt
- All right welcome to lecture nine. So today we will be talking about CNN Architectures. And just a few administrative points before we get started, assignment two is due Thursday. The mid term will be in class on Tuesday May ninth, so next week and it will cover material through Tuesday through this coming Thursday M...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_16_Adversarial_Examples_and_Adversarial_Training.txt
- Okay, sounds like it is. I'll be telling you about adversarial examples and adversarial training today. Thank you. As an overview, I will start off by telling you what adversarial examples are, and then I'll explain why they happen, why it's possible for them to exist. I'll talk a little bit about how adversarial exa...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_8_Deep_Learning_Software.txt
- Hello? Okay, it's after 12, so I want to get started. So today, lecture eight, we're going to talk about deep learning software. This is a super exciting topic because it changes a lot every year. But also means it's a lot of work to give this lecture 'cause it changes a lot every year. But as usual, a couple adminis...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_15_Efficient_Methods_and_Hardware_for_Deep_Learning.txt
- Hello everyone, welcome to CS231. I'm Song Han. Today I'm going to give a guest lecture on the efficient methods and hardware for deep learning. So I'm a fifth year PhD candidate here at Stanford, advised by Professor Bill Dally. So, in this course we have seen a lot of convolution neural networks, recurrent neural n...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_4_Introduction_to_Neural_Networks.txt
[students murmuring] - Okay, so good afternoon everyone, let's get started. So hi, so for those of you who I haven't met yet, my name is Serena Yeung and I'm the third and final instructor for this class, and I'm also a PhD student in Fei-Fei's group. Okay, so today we're going to talk about backpropagation and neural ...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_5_Convolutional_Neural_Networks.txt
- Okay, let's get started. Alright, so welcome to lecture five. Today we're going to be getting to the title of the class, Convolutional Neural Networks. Okay, so a couple of administrative details before we get started. Assignment one is due Thursday, April 20, 11:59 p.m. on Canvas. We're also going to be releasing as...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_13_Generative_Models.txt
- Okay we have a lot to cover today so let's get started. Today we'll be talking about Generative Models. And before we start, a few administrative details. So midterm grades will be released on Gradescope this week A reminder that A3 is due next Friday May 26th. The HyperQuest deadline for extra credit you can do this...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_1_Introduction_to_Convolutional_Neural_Networks_for_Visual_Recognition.txt
- So welcome everyone to CS231n. I'm super excited to offer this class again for the third time. It seems that every time we offer this class it's growing exponentially unlike most things in the world. This is the third time we're teaching this class. The first time we had 150 students. Last year, we had 350 students, ...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_11_Detection_and_Segmentation.txt
- Hello, hi. So I want to get started. Welcome to CS 231N Lecture 11. We're going to talk about today detection segmentation and a whole bunch of other really exciting topics around core computer vision tasks. But as usual, a couple administrative notes. So last time you obviously took the midterm, we didn't have lectu...
Lecture_Collection_Convolutional_Neural_Networks_for_Visual_Recognition_Spring_2017
Lecture_12_Visualizing_and_Understanding.txt
- Good morning. So, it's 12:03 so, I want to get started. Welcome to Lecture 12, of CS-231N. Today we are going to talk about Visualizing and Understanding convolutional networks. This is always a super fun lecture to give because we get to look a lot of pretty pictures. So, it's, it's one of my favorites. As usual a c...
History_vs
What_makes_Thomas_Jefferson_so_controversial_Frank_Cogliano.txt
He was part of America's fight for freedom and equality. But were his enlightened principles outweighed by participation in a greater injustice? Find out on History versus Thomas Jefferson. Order! Order! Hey, that’s one of the guys from Mt. Rushmore. Ahem. This is Thomas Jefferson, founding father of the United State...
History_vs
모의_법정_역사_대_리처드_닉슨_사건_알렉스_겐들러.txt
The presidency of the United States of America is often said to be one of the most powerful positions in the world. But of all the U.S. presidents accused of misusing that power, only one has left office as a result. Does Richard Nixon deserve to be remembered for more than the scandal that ended his presidency? Find o...
History_vs
History_vs_Tamerlane_the_Conqueror_Stephanie_Honchell_Smith.txt
He was born in the 1330s in the Chaghatayid Khanate formerly the Mongol Empire in Central Asia. On the unforgiving steppe, he rose from a lowly sheep thief to become one of history’s greatest conquerors, uniting nearly all of Central Asia, Afghanistan, and Iran under his rule. But was he a great state builder or a ...
History_vs
History_vs_Egypts_most_powerful_pharaoh_Jessica_Tomkins.txt
Pharaoh Ramesses II reigned for almost 70 years in the 13th century BCE. He presided over a golden age of Egyptian prosperity. But was he a model leader, or a shameless egomaniac and master of propaganda? Order! Order! Who do we have on the stand? Ramesses II? Ahem, I believe you mean "The strong bull, protector of Egy...
History_vs
History_vs_Cleopatra_Alex_Gendler.txt
"Order, order. So who do we have here?" "Your Honor, this is Cleopatra, the Egyptian queen whose lurid affairs destroyed two of Rome's finest generals and brought the end of the Republic." "Your Honor, this is Cleopatra, one of the most powerful women in history whose reign brought Egypt nearly 22 years of stability an...