• Proceedings of the Korea Information Processing Society Conference
• /
• 2023.05a
• /
• pp.519-521
• /
• 2023

온라인 뉴스 플랫폼의 발전은 에코 챔버(echo chamber) 효과와 정치적 양극화를 심화시키며, 이를 완화하기 위한 선행 연구로 뉴스 기사의 정치적 성향을 판단하는 연구가 필요하다. 기존 연구는 외부 지식 그래프를 활용하여 뉴스 기사의 텍스트 정보를 더욱 풍부하게 표현한다. 그러나, 외부 지식을 임베딩하는 지식 그래프 임베딩(knowledge graph embedding, KGE) 방법은 다양하며, 각 KGE 방법이 정치적 성향 예측 정확도에 미치는 효과에 대해서 충분히 연구되지 않았다. 본 논문에서는 정치적 성향 예측에 외부 지식의 활용을 최대화하기 위한 다양한 KGE 방법들의 효과를 분석한다. 실험 결과, 외부 지식 그래프 내의 개체들 간 복잡한 관계를 간단하고 정확하게 표현 가능한 ModE 방법을 활용하는 것이 정치적 성향 예측에 가장 효과적이라는 것을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.16 no.11
• /
• pp.3761-3779
• /
• 2022

The performance of existing recognition algorithms for binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) signals degrade under conditions of low signal-to-noise ratios (SNR). Hence, a novel recognition algorithm based on features in the graph domain is proposed in this study. First, the power spectrum of the squared candidate signal is truncated by a rectangular window. Thereafter, the graph representation of the truncated spectrum is obtained via normalization, quantization, and edge construction. Based on the analysis of the connectivity difference of the graphs under different hypotheses, the sum of degree (SD) of the graphs is utilized as a discriminate feature to classify BPSK and QPSK signals. Moreover, we prove that the SD is a Schur-concave function with respect to the probability vector of the vertices (PVV). Extensive simulations confirm the effectiveness of the proposed algorithm, and its superiority to the listed model-driven-based (MDB) algorithms in terms of recognition performance under low SNRs and computational complexity. As it is confirmed that the proposed method reduces the computational complexity of existing graph-based algorithms, it can be applied in modulation recognition of radar or communication signals in real-time processing, and does not require any prior knowledge about the training sets, channel coefficients, or noise power.

• KIISE Transactions on Computing Practices
• /
• v.21 no.7
• /
• pp.482-487
• /
• 2015

This paper presents the results and the process of extracting correlations between events of prescriptions and examinations using graph-modeling and node centrality measures on a medical dataset of 11,938 patients with diabetes mellitus. As the data is stored in relational form, RDB2Graph framework was used to construct effective graph models from the data. Personalized PageRank was applied to analyze correlation between prescriptions and examinations of the patients. Two graph models were constructed: one that models medical events by each patient and another that considers the time gap between medical events. The results of the correlation analysis confirm current medical knowledge. The paper demonstrates some of the note-worthy findings to show the effectiveness of the method used in the current analysis.

• Proceedings of the Korea Inteligent Information System Society Conference
• /
• 1999.10a
• /
• pp.121-130
• /
• 1999

The objective of this paper is to apply Extended AND-OR Graph (EAOG)-related techniques to extract knowledge from a specific problem-domain and perform analysis in complicated decision making area. Expert systems use expertise about a specific domain as their primary source of solving problems belonging to that domain. However, such expertise is complicated as well as uncertain, because most knowledge is expressed in causal relationships between concepts or variables. Therefore, if expert systems can be used effectively to provide more intelligent support for decision making in complicated specific problems, it should be equipped with real-time inference mechanism. We develop two kinds of EAOG-driven inference mechanisms(1) EAOG-based forward chaining and (2) EAOG-based backward chaining. and The EAOG method processes the following three characteristics. 1. Real-time inference : The EAOG inference mechanism is suitable for the real-time inference because its computational mechanism is based on matrix computation. 2. Matrix operation : All the subjective knowledge is delineated in a matrix form, so that inference process can proceed based on the matrix operation which is computationally efficient. 3. Bi-directional inference : Traditional inference method of expert systems is based on either forward chaining or backward chaining which is mutually exclusive in terms of logical process and computational efficiency. However, the proposed EAOG inference mechanism is generically bi-directional without loss of both speed and efficiency.

• Journal of the Korea Society of Computer and Information
• /
• v.27 no.9
• /
• pp.77-89
• /
• 2022

In this paper, we propose a system which automatically generates SHACL schemas to describe and validate RDF knowledge graphs constructed by RML mappings. Unlike existing studies, the proposed system generates the schemas based on not only RML mapping rules but also metadata extracted from RML mapping input data in various formats such as CSV, JSON, XML or databases. Therefore, our schemas include the constraints on data type, string length, value range and cardinality, which were not present in the existing schemas. And we solves the problem with "repeated properties" which overlooked in existing studies. Through a conformance test consisting of 297 cases, we show that the proposed system generates correct constraints for the graphs. The proposed system can contribute to automation of the tedious and error-prone existing manual validation processes.

• Journal of Internet Computing and Services
• /
• v.21 no.1
• /
• pp.79-85
• /
• 2020

Today, to block spam texts on smartphone, a simple string comparison between text messages and spam keywords or a blocking spam phone numbers is used. As results, spam text is sent in a gradually hanged way to prevent if from being automatically blocked. In particular, for words included in spam keywords, spam texts are sent to abnormal words using special characters, Chinese characters, and whitespace to prevent them from being detected by simple string match. There is a limit that traditional spam filtering methods can't block these spam texts well. Therefore, new technologies are needed to respond to changing spam text messages. In this paper, we propose a knowledge graph-based new words detection mechanism that can detect new words frequently used in spam texts and respond to changing spam texts. Also, we show experimental results of the performance when detected Korean new words are applied to the Naive Bayes algorithm.

• Journal of the Korea Society of Computer and Information
• /
• v.27 no.11
• /
• pp.67-80
• /
• 2022

In this paper, we propose a system which automatically generates the ShEx schemas to describe and validate RDF knowledge graphs constructed by RML mapping. ShEx schemas consist of constraints. The proposed system generates most of the constraints by converting the RML mapping rules. The schemas consisting only of constraints obtained from mapping rules can help users to figure out the structure of the graphs generated by RML mapping, but they are not sufficient for sophisticated validation purposes. For users who need a schema for validation, the proposed system is also able to provide the schema with added constraints generated from metadata extracted from the input data sources for RML mapping. The proposed system has the ability to handle CSV, XML, JSON or RDBMS as input data sources. Testing results from 297 cases show that the proposed system can be applied for RDF graph validation in various practical cases.

• Journal of the Korean Society for information Management
• /
• v.40 no.4
• /
• pp.329-349
• /
• 2023

With the rapid development of information and communication technology, the speed of data production has increased rapidly, and this is represented by the concept of big data. Discussions on quality and reliability are also underway for big data whose data scale has rapidly increased in a short period of time. On the other hand, small data is minimal data of excellent quality and means data necessary for a specific problem situation. In the field of culture and arts, data of various types and topics exist, and research using big data technology is being conducted. However, research on whether basic information about culture and arts institutions is accurately provided and utilized is insufficient. The basic information of an institution can be an essential basis used in most big data analysis and becomes a starting point for identifying an institution. This study collected data dealing with the basic information of culture and arts institutions to define common metadata and constructed small data in the form of a knowledge graph linking institutions around common metadata. This can be a way to explore the types and characteristics of culture and arts institutions in an integrated way.

• Knowledge Management Research
• /
• v.9 no.2
• /
• pp.87-107
• /
• 2008

The knowledge society has come to where the knowledge is the source of wealth contrary to the traditional era that labor and capital were the source of wealth. Thus, corporate is accelerating to introduce the knowledge management and to establish the knowledge management system (KMS) in order to effectively manage the knowledge that can be the source of their competitiveness. The purpose of this paper is to identify the factors which affect knowledge sharing and to prove empirically their relationships with the KMS performance. A survey was conducted and data were collected from 220 respondents of 19 organizations which have adopted KMS. Research model and related hypotheses were tested using PLS Graph 3.0. As a result of data analysis, seven hypotheses out of eleven hypotheses were supported. In particular, knowledge sharing is significantly influenced by those knowledge sharing factors such as openness, trust, training, reward system, perceived usefulness, and communication channel. Also, individual impact is significantly affected by knowledge sharing. This study is expected to provide a sound basis for understanding the importance of knowledge sharing to gain organizational as well as individual competitiveness and exploring ways to effectively share knowledge through enhancing the use of KMS in organizations.

• Journal of KIISE:Computer Systems and Theory
• /
• v.33 no.7
• /
• pp.448-453
• /
• 2006

We extend a parallel depth-first search (DFS) algorithm for planar graphs to deal with (non-planar) solid grid graphs, a subclass of non-planar grid graphs. The proposed algorithm takes time O(log n) with $O(n/sqrt{log\;n})$ processors in Priority PRAM model. In our knowledge, this is the first deterministic NC algorithm for a non-planar graph class.