Sachio Hirokawa

ORCID: 0000-0002-8050-1109
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About
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Research Areas
  • Web Data Mining and Analysis
  • Advanced Text Analysis Techniques
  • Natural Language Processing Techniques
  • Educational Technology and Assessment
  • Semantic Web and Ontologies
  • Online Learning and Analytics
  • Recommender Systems and Techniques
  • Algorithms and Data Compression
  • Text and Document Classification Technologies
  • Topic Modeling
  • Logic, Reasoning, and Knowledge
  • Logic, programming, and type systems
  • Digital Marketing and Social Media
  • Biomedical Text Mining and Ontologies
  • Data Mining Algorithms and Applications
  • scientometrics and bibliometrics research
  • Data Management and Algorithms
  • Formal Methods in Verification
  • Advanced Malware Detection Techniques
  • Video Analysis and Summarization
  • Advanced Computational Techniques and Applications
  • Text Readability and Simplification
  • Complex Network Analysis Techniques
  • Intelligent Tutoring Systems and Adaptive Learning
  • Diverse Approaches in Healthcare and Education Studies

University of Fukuchiyama
2022

Advanced Institute of Industrial Technology
2018-2022

Kyushu University
2012-2021

Oldenburger Institut für Informatik
2010-2020

Tokyo Metropolitan University
2020

Kyushu Institute of Information Sciences
2007-2019

Binus University
2019

Saiseikai Kumamoto Hospital
2018

Shizuoka University
1984-2018

Kyushu University Hospital
2018

Recommender system is an effective way to help users obtain the personalized and useful information. However, due complexity dynamic, traditional recommender cannot work well in mobile environment. In this paper, we propose a restaurant This adopts user preference model by using features of user's visited restaurants, also utilizes location information restaurants dynamically generate recommendation results. Baidu map cloud service used implement proposed system. The result case study shows...

10.1109/iiai-aai.2016.126 article EN 2016-07-01

In this paper we propose a new approach based on text mining techniques for predicting student performance using LSA (latent semantic analysis) and K-means clustering methods. The present study uses free-style comments written by students after each lesson. Since the potentials of these can reflect learning attitudes, understanding subjects difficulties lessons, they enable teachers to grasp tendencies activities. To improve our basic k-means, overlap similarity measuring methods are...

10.2197/ipsjjip.23.192 article EN Journal of Information Processing 2015-01-01

Collaborative filtering (CF) has been widely used in recommender systems to generate personalized recommendations. However, using CF are vulnerable shilling attacks, which attackers inject fake profiles manipulate recommendation results. Thus, attacks pose a threat the credibility of systems. Previous studies mainly derive features from characteristics item ratings user detect attackers, but methods suffer low accuracy when adopt new rating patterns. To overcome this drawback, we properties...

10.1587/transinf.2015edp7500 article EN IEICE Transactions on Information and Systems 2016-01-01

Literature review requires understanding the contents from several view points, such as problem and method that articles describe. Search these viewpoints will improve efficiency of survey, if particular segments were extracted, indexed can be used auxiliary query. This paper focuses on sentences describe in an abstract feature sets classify sentences. Classification performance are evaluated by 10-fold cross-validation for six candidate words. It turned out set all words gains best 90% data...

10.1145/2428736.2428803 article EN 2012-12-03

The bug reports expressed in natural language text usually suffer from vast, ambiguous and poorly written, which causes the challenge to duplicate detection. Current automatic detection techniques have mainly focused on textual information ignored some useful factors. To improve accuracy, this paper, we propose a new approach calls LNG (LDA N-gram) model takes advantages of topic LDA word-based N-gram. considers multiple factors, including information, semantic correlation, word order,...

10.1587/transinf.2016edp7052 article EN IEICE Transactions on Information and Systems 2016-01-01

Search results generated by searchable databases are served dynamically and far larger than the static documents on Web. These pages have been referred to as Deep We need extract target data in integrate them different databases. propose a test bed for information extraction from search results. chose 100 randomly 114,540 with forms. Therefore, these good variety. selected 51 which include URLs pageand manually identify be extracted. also suggest evaluation measures comparing methods extending data.

10.1145/1013367.1013468 article EN 2004-01-01

Analyses on students’ learning behaviors comprise an important thrust in education research. This study focused e-books system used the classroom and this recorded logs their daily academic life. These can be to analysis behaviors. By performing partial correlation analysis, found that a number of have significant relation with test scores.

10.58459/icce.2015.1514 article EN International Conference on Computers in Education 2015-11-30

Predicting students' academic achievement with high accuracy has an important vital role in many disciplines. Most recent studies indicate the of data type selection. They also attempt to understand individual students more deeply by analyzing questionnaire for a particular purpose. The present study uses free-style comments written after each lesson, predict their performance. These reflect learning attitudes understanding subjects, difficulties learn, and activities classroom. To reveal...

10.1109/fie.2014.7044399 article EN 2014-10-01

To grasp a student's lesson attitude and learning situation to give feed back each student are educational foundations. Goda et al. proposed the PCN method estimate from comment freely written by students[6, 7]. The categorizes comments into three items of P (previous), C(current) N(next).

10.1145/2512276.2512294 article EN 2013-10-02

With the rapid development of information and Web technologies, people are facing 'information overload' in their daily lives.The personalized recommendation system (PRS) is an effective tool to assist users extract meaningful from big data.Collaborative filtering (CF) one most widely used techniques recommend products for users.However, conventional CF technique has some limitations, such as low accuracy similarity calculation, cold start problem, etc.In this paper, a PRS model based on...

10.1587/transinf.2016edp7054 article EN IEICE Transactions on Information and Systems 2017-01-01

We propose a method that constructs hierarchy of words from set given documents automatically and dynamically. Given query, the system retrieves satisfy related are extracted automatically, according their document frequencies. Then hypernym relations these obtained using co-occurrence Empirical evaluation conducted for word derived an English-Japanese dictionary, where descriptions is considered as one documents. It shown meaningful structures obtained. also proposed generates more fine...

10.1109/cisis.2008.63 article EN ˜... œInternational Conference on Complex, Intelligent and Software Intensive Systems 2008-01-01

The typed λμ-calculus is known to be strongly normalizing and weakly Church-Rosser, hence becomes confluent. In fact, Parigot formulated a parallel reduction prove confluence of the by "Tait-and-Martin-Löf" method. However, diamond property does not hold for his reduction. type-free cannot derived from that confirmed yet as far we know. We analyze granularity rules, then introduce new such both renaming consecutive structural reductions are considered one step It shown formulation has...

10.1016/s1571-0661(04)80878-8 article EN Electronic Notes in Theoretical Computer Science 2001-01-01

Predicting student final score from student's attributes is an important issue of learning analytic. Not only to achieve high prediction performance but also identifying the key research theme. This paper evaluated exhaustively based on all possible combinations four types - behavioral features, demographic academic background, and parent participation. The features are given as numerical data. But, we represented them pair attribute name value. vectorization yields 417 dimensional data,...

10.1145/3290511.3290576 article EN 2018-10-26

This paper compares the prediction performance of document classification based on a variety feature selection measures. Empirical experiments were conducted for dataset re0 with 10 measures and SVM. It is confirmed that SVM-score proposed by Sakai Hirokawa (2012) outperforms standard small number features. In fact, 100 words are enough to get similar obtained all words. The reason good this capture not only characteristic positive samples but negative as well.

10.1145/3011141.3011190 article EN 2016-11-28

Government 2.0 activities have become very attractive and popular these days. Using platforms to support the activities, anyone can anytime report issues or complaints in a city with their photographs geographical information on Web, share them other people. Since variety of reports are posted, officials management section check importance each sort out priorities reports. However, it is not easy task judge When several work task, agreement rate judgments always high. Even if done by only...

10.1145/3106426.3106520 article EN Proceedings of the International Conference on Web Intelligence 2017-08-10

In order to overcome mistakes, learners need feedback prompt reflection on their errors.This is a particularly important issue in education systems as the system effectiveness finding errors or mistakes could have an impact learning.Finding essential providing appropriate guidance for flaws.Traditionally task of writing takes time and effort.The authors this paper long-term research goal creating tools learners, especially autonomous enable them be more aware provide way reflect errors.As...

10.1504/ijkwi.2014.065063 article EN International Journal of Knowledge and Web Intelligence 2014-01-01

The present study proposes prediction approaches of student's grade based on their comments data. Students describe learning attitudes, tendencies and behaviors by writing freely after each lesson. main difficulty this research is to predict students' performance separately using two class data in Although students learn the same subject, there exist differences between classes. proposed methods basically employ latent semantic analysis (LSA) types machine technique: SVM (support vector...

10.1109/iiai-aai.2014.17 article EN 2014-08-01

10.1016/0304-3975(93)90171-o article EN Theoretical Computer Science 1993-01-01
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