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中文詞彙集的來源與權重對中文裁判書分類成效的影響 / Exploring the Influences of Lexical Sources and Term Weights on the Classification of Chinese Judgment Documents

國外法學資訊系統已研究多年,嘗試利用科技幫助提昇司法審判的效率。重要的議題包括輔助判決,法律文件分類,或是相似案件搜尋等。本研究將針對中文裁判書的分類做進一步談討。
在文件特徵表示方面,我們以有序詞組來表達中文裁判書,我們嘗試比較採用不同的詞彙來源對於分類效果的影響。實驗中我們分別採用一般通用的電子詞典建立一般詞組;以及以演算法取出法學專業詞彙集建立專業詞組。並依tf-idf(term frequency – inverse document frequency)的概念,設計兩種詞組權重tpf-idf(term pair frequency – inverse document frequency)以及tpf-icf(term pair frequency – inverse category frequency),來計算特徵詞組權重。
在文件分類演算法方面,我們實作以相似度為基礎的k最近鄰居法作為系統分類機制,藉由裁判書的案由欄位,將案例分為七種類別,分別為竊盜、搶奪、強盜、贓物、傷害、恐嚇以及賭博。並藉由觀察案例資料庫的相似度分佈,以找出恰當的參數,進一步得到較佳的分類正確率與較低的拒絕率。
我們並依照自省式學習法的精神,建立權重調整的機制。企圖藉由自省式學習法提昇分類效果,以及找出對分類有影響的詞組。而我們以案例資料庫的相似度差異值以及距離差異值,分析調整前後案例資料庫的變化,藉以觀察自省式學習法的效果。 / Legal information systems for non-Chinese languages have been studied intensively in the past many years. There are several topics under discussion, such as judgment assistance, legal document classification, and similar case search, and so on. This thesis studies the classification of Chinese judgment documents.
I use phrases as the indices for documents. I attempt to compare the influences of different lexical sources for segmenting Chinese text. One of the lexical sources is a general machine-readable dictionary, Hownet, and the other is the set of terms algorithmically extracted from legal documents. Based on the concept of tf-idf, I design two kinds of phrase weights: tpf-idf and tpf-icf.
In the experiments, I use the k-nearest neighbor method to classify Chinese judgment documents into seven categories based on their prosecution reasons: larceny(竊盜), robbery (搶奪), robbery by threatening or disabling the victims (強盜), receiving stolen property (贓物), causing bodily harm (傷害), intimidation (恐嚇), and gambling(賭博). To achieve high accuracy with low rejection rates, I observe and discuss the distribution of similarity of the training documents to select appropriate parameters. In addition, I also conduct a set of analogous experiments for classifying documents based on the cited legal articles for gambling cases.
To improve the classification effects, I apply the introspective learning technique to adjust the weights of phrases. I observe the intra-cluster similarity and inter-cluster similarity in evaluating the effects of weight adjustment on experiments for classifying documents based on their prosecution reasons and cited articles.

Identiferoai:union.ndltd.org:CHENGCHI/G0093753030
Creators鄭人豪, Cheng, Jen-Hao
Publisher國立政治大學
Source SetsNational Chengchi University Libraries
Language中文
Detected LanguageEnglish
Typetext
RightsCopyright © nccu library on behalf of the copyright holders

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