--- task_categories: - text-generation - fill-mask - feature-extraction language: - el tags: - greek - theses - dissertations - academic - university-of-crete - pdf - ocr - institutional-repository pretty_name: E-Locus Dataset size_categories: - 1K//` markup with HTML entities (`>`, `<`) - this is intentional structured output, not corruption. | | `abstract` | string | The thesis abstract as supplied to the repository by the depositor. May be empty (≈ 36.5 % of records - 2,824 / 7,731 - have an empty abstract at the source). When present, length ranges from a few hundred characters up to ≈ 25 K. | | `author` | string | Name of the thesis author, in the form `Surname, Given Name(s)` (Greek script). Always populated for 99.6 % of rows; 31 records carry an empty author field at the source. | | `advisor` | string | Name of the thesis supervisor / advisor. Often populated, but 1,418 records (≈ 18.3 %) carry an empty value at the source (older or pre-policy records). | | `committee_members` | string | Semicolon-separated list of the rest of the examination / supervisory committee, e.g. `Surname1, Given1; Surname2, Given2`. Often empty at the source (4,610 records ≈ 59.6 %). | | `subjects` | string | Subject / keyword string in the form `term1; term2; …`, typically bilingual (English and Greek terms interleaved). May be empty (3,006 records ≈ 38.9 %). Maps to Dublin Core `dc:subject` at the source. | | `alt_title` | string | Alternative title - almost always the English translation of the Greek `title`. May be empty (3,237 records ≈ 41.9 %). | | `date` | string | Date of the defense / publication, stored as it appears at the source. Most values are full `YYYY-MM-DD` strings; some are bare `YYYY` (year-only). Date range spans 1988-07-01 → 2026-03-30. Maps to Dublin Core `dc:date`. | | `collection` | string | Hierarchical breadcrumb encoding (a) the School / Department / Programme that issued the thesis and (b) the type of work, in the form `Σχολή/Τμήμα------ \| Τύπος Εργασίας--`. 103 distinct collection values across the dataset. The most-populous collections are Medical School theses, Department of Psychology programmes, and various Faculty of Science and Engineering postgraduate programmes. | | `physical_description` | string | MARC-style physical description (page count, illustrations, dimensions) - e.g. `49 σ. : χάρτ., πίν., έγχ. εικ. ; 30 εκ.`. Often empty (1,207 records). | | `url` | string | Direct HTTPS link to the E-Locus metadata landing page for the record, e.g. `https://elocus.lib.uoc.gr/dlib/8/8/7/metadata-dlib-1772878887-83781-18163.tkl`. Always populated, always under `elocus.lib.uoc.gr`, and unique per row. | | `pdf_url` | string | Direct HTTPS link to the attached PDF file, e.g. `https://elocus.lib.uoc.gr//dlib/8/8/7/attached-metadata-dlib-1772878887-83781-18163/EYAGGELIA_GARA_2026_METAPTYXIAKH_ERGASIA.pdf`. Always populated, always under `elocus.lib.uoc.gr`, and unique per row. The double slash `//dlib` after the hostname is the form produced by the source repository and is preserved verbatim. | **Dataset Statistics:** Records: 7,731 Words: 279,726,210 Tokens: 568,723,589 _(WordPiece tokens from `nlpaueb/bert-base-greek-uncased-v1`, computed on `title` + `abstract` + `content` combined. The three columns split as: `title` 162,107 tokens, `abstract` 2,851,103 tokens, `content` 565,710,379 tokens - i.e. `content` carries > 99.4 % of the corpus.)_ Size: 1.34 GB (parquet on disk) - ≈ 2.04 GB of plain text once decoded. **Known Data Quality Notes:** The source documents are PDFs deposited at E-Locus over a span of nearly forty years (1988 – present), and the `content` column carries the text extraction of those PDFs. Some level of extraction noise is therefore expected and inherent to the source material. Born-digital theses produced with modern LaTeX or Word tooling extract cleanly, but older scanned or low-quality PDFs do not. Our policy is to publish the extracted text as faithfully as possible to the underlying PDFs rather than aggressively post-process it: this preserves reproducibility and lets downstream users apply their own filtering, re-OCR or normalization strategy as appropriate to their task. - **Empty bibliographic fields at the source.** Several metadata columns carry empty strings (not nulls) where the depositor did not supply that field - most notably `committee_members` (≈ 59.6 % empty), `alt_title` (≈ 41.9 %), `subjects` (≈ 38.9 %), `abstract` (≈ 36.5 %), `advisor` (≈ 18.3 %), `physical_description` (≈ 15.6 %), and `author` (31 records). These reflect repository data as supplied; we do not synthesise placeholders. - **Mixed `date` granularity.** Most dates are full `YYYY-MM-DD`; some are bare `YYYY`. Both forms are preserved verbatim, parseable with `pandas.to_datetime(..., errors='coerce')`. - **Generated HTML markup inside `content`.** The PDF-to-text extractor emits `//
` tags with HTML entities (`>`, `<`, ` `) when it detects a table on the page. This is structured output, not corruption: it appears in 6,133 of 7,731 records and the embedded HTML entities account for the ≈ 1,520 "encoding artifact" hits in the QA scan. Strip or parse it depending on whether your downstream pipeline wants structured tables. - **Trailing whitespace.** 710 of 7,731 `content` values end in trailing whitespace (rogue newlines from the extractor) and 3 `collection` values carry trailing whitespace. Easy to `.strip()` if desired, but left as-is in the published file to preserve byte-for-byte fidelity to the extraction step. - **Unicode replacement characters.** 59 `content` rows contain `\ufffd` (the replacement character), typically clustered in a few hard-to-OCR pages of older scanned PDFs. These are PDF-extraction defects at the source and are not removed. - **Duplicate non-`content` cells are expected.** Bibliographic fields like `advisor`, `committee_members`, `collection`, `date`, `subjects` and `physical_description` legitimately repeat across rows - e.g. one advisor supervised 75 theses, the most-populous collection has 827 rows, and the most common physical description (`92 σ. ; 30 εκ.`) appears on 31 records. No `content`, `url` or `pdf_url` value is duplicated. - **Mojibake-shaped substrings inside content.** The QA scan flags ≈ 1,520 rows for "encoding artifacts"; on inspection essentially all hits are HTML entities inside the extractor's emitted `` markup, not actual UTF-8/Latin-1 corruption. Treat the figure as an upper bound, not as the count of corrupt records. - **Date coverage is not uniform.** The repository is sparsely populated for early years (1 – 2 records / year in 1988 – 1993) and reaches its peak coverage from 2007 onwards (150 – 295 records / year). The biggest coverage gap is 638 days between 1990-01-01 and 1991-10-01. Consider this when using `date` for temporal slicing. **License:** The dataset compilation, metadata schema, text-extraction pipeline and accompanying tooling are released under **Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)**. The **underlying texts** (each individual thesis or dissertation) remain the intellectual property of their original authors, as established under Greek copyright law. E-Locus hosts these works under an open-access mandate of the University of Crete Library, but does not declare a machine-readable per-item licence. The dataset is therefore offered for **non-commercial academic and research use only**. Downstream users who wish to use any individual thesis commercially, or to redistribute it outside research contexts, must independently obtain permission from the thesis's author and/or the Library and Information Center of the University of Crete. When using this dataset, please attribute both the original repository and this derivative compilation: > _E-Locus Dataset_, derived from the open-access institutional repository of the Library and Information Center of the University of Crete (`elocus.lib.uoc.gr`), licensed under CC BY-NC-SA 4.0. **Source:** E-Locus - Institutional Repository of the Library and Information Center of the University of Crete (Ιδρυματικό Καταθετήριο Βιβλιοθήκης Πανεπιστημίου Κρήτης), `elocus.lib.uoc.gr`. Registered in OpenDOAR (#1464) and ROAR (#4552).