• Title/Summary/Keyword: Graph property

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Exploratory study on the Spam Detection of the Online Social Network based on Graph Properties (그래프 속성을 이용한 온라인 소셜 네트워크 스팸 탐지 동향 분석)

  • Jeong, Sihyun;Oh, Hayoung
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.24 no.5
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    • pp.567-575
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    • 2020
  • As online social networks are used as a critical medium for modern people's information sharing and relationship, their users are increasing rapidly every year. This not only increases usage but also surpasses the existing media in terms of information credibility. Therefore, emerging marketing strategies are deliberately attacking social networks. As a result, public opinion, which should be formed naturally, is artificially formed by online attacks, and many people trust it. Therefore, many studies have been conducted to detect agents attacking online social networks. In this paper, we analyze the trends of researches attempting to detect such online social network attackers, focusing on researches using social network graph characteristics. While the existing content-based techniques may represent classification errors due to privacy infringement and changes in attack strategies, the graph-based method proposes a more robust detection method using attacker patterns.

A Study on the Methodologies to Assess Network Vulnerability (네트워크 위험 분석 및 취약점 점검 방법에 관한 연구)

  • Seo Dong-Il;Park Won-Joo
    • The Journal of the Korea Contents Association
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    • v.5 no.2
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    • pp.107-114
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    • 2005
  • This paper proposes to analyze a security level about information property systems. This method uses objective and quantitative risk level assessment. The method analyzes administrative, physical and technical aspects of information property system commonly. This method also uses administrative, physical and technical weights. Individually according to requirements security assessment purpose. And it shows risks weighting mean and importance of information property by graph. The most right and up systems in maps is prior to other systems. Also, Quantitative analysis presents more objective and efficient results for security level assessment of information system.

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Evaluation of Structural Safety for Hydrogen Tube Trailer Considering Dynamic Property (동적 특성을 고려한 수소 튜브 트레일러의 구조 안전성 평가)

  • Y. B. Kim;M. G. Kim;D. C. Ko
    • Transactions of Materials Processing
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    • v.33 no.3
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    • pp.169-177
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    • 2024
  • Recently, hydrogen energy has been widely used because of strict regulations on greenhouse gas emissions. For using the hydrogen energy, it is required to supply hydrogen through a tube trailer. However hydrogen tube trailer can have excessive load problems during transportation due to reasons such as road shape and driving method, which may lead a risk of hydrogen leakage. So it is necessary to secure a high level of safety. The purpose of this study is to evaluate structural safety for the conservative design of hydrogen tube trailer. First, finite element(FE) modeling of the designed hydrogen tube trailer was performed. After that, safety evaluation method was established through static structural simulation based on the standard GC207 conditions. In addition, effectiveness of the designed model was confirmed through the results of the structural safety evaluation. Finally, driving simulation was used to derive acceleration graph according to time, which was considered as a dynamic property for the evaluation of conservative tube trailer safety evaluation. And dynamic structural simulation was conducted as a condition for actual transportation of tube trailer by applying dynamic properties. As a results, conservative safety was evaluated through dynamic structural simulation and the safety of hydrogen tube trailer was confirmed through satisfaction of the safety rate.

Layout Based Multimodal Contents Aughoring Tool for Digilog Book (디지로그 북을 위한 레이아웃 기반 다감각 콘텐츠 저작 도구)

  • Park, Jong-Hee;Woo, Woon-Tack
    • 한국HCI학회:학술대회논문집
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    • 2009.02a
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    • pp.512-515
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    • 2009
  • In this paper, we propose layout based multimodal contents authoring tool for Digilog Book. In authoring step, users create a virtual area using mouse or pen-type device and select property of the area repetitively. After finishing authoring step, system recognizes printed page number and generate page layout including areas and property information. Page layout is represented as a scene graph and stored as XML format. Digilog Book viewer loads stored page layout and analyze properties then augment virtual contents or execute functions based on area. Users can author visual and auditory contents easily by using hybrid interface. In AR environment, system provides area templates in order to help creating area. In addition, proposed authoring tool separates page recognition module from page tracking module. So, it is possible to author many pages using only single marker. As a result of experiment, we showed proposed authoring tool has reasonable performance time in AR environment. We expect that proposed authoring tool would be applicable to many fields such as education and publication.

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Finite-Time Sliding Mode Controller Design for Formation Control of Multi-Agent Mobile Robots (다중 에이전트 모바일 로봇 대형제어를 위한 유한시간 슬라이딩 모드 제어기 설계)

  • Park, Dong-Ju;Moon, Jeong-Whan;Han, Seong-Ik
    • The Journal of Korea Robotics Society
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    • v.12 no.3
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    • pp.339-349
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    • 2017
  • In this paper, we present a finite-time sliding mode control (FSMC) with an integral finite-time sliding surface for applying the concept of graph theory to a distributed wheeled mobile robot (WMR) system. The kinematic and dynamic property of the WMR system are considered simultaneously to design a finite-time sliding mode controller. Next, consensus and formation control laws for distributed WMR systems are derived by using the graph theory. The kinematic and dynamic controllers are applied simultaneously to compensate the dynamic effect of the WMR system. Compared to the conventional sliding mode control (SMC), fast convergence is assured and the finite-time performance index is derived using extended Lyapunov function with adaptive law to describe the uncertainty. Numerical simulation results of formation control for WMR systems shows the efficacy of the proposed controller.

Local Model Checking for Verification of Real-Time Systems (실시간 시스템 검증을 위한 지역모형 검사)

  • 박재호;김성길;황선호;김성운
    • Journal of Korea Multimedia Society
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    • v.3 no.1
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    • pp.77-90
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    • 2000
  • Real-Time verification is a procedure that verifies the correctness of specification related to requirement in time as well as in logic. One serious problem encountered in the verification task is that the state space grows exponentially owing to the unboundedness of time, which is termed the state space explosion problem. In this paper, we propose a real-time verification technique checking the correctness of specification by showing that a system model described in timed automata is equivalent to the characteristic of system property specified in timed modal-mu calculus. For this, we propose a local model checking method based on the value of the formula in initial state with constructing product graph concerned to only the nodes needed for verification process. Since this method does not search for every state of system model, the state space is reduced drastically so that the proposed method can be applied effectively to real-time system verification.

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An Optimization of Representation of Boolean Functions Using OPKFDD (OPKFDD를 이용한 불리안 함수 표현의 최적화)

  • Jung, Mi-Gyoung;Lee, Hyuck;Lee, Guee-Sang
    • The Transactions of the Korea Information Processing Society
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    • v.6 no.3
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    • pp.781-791
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    • 1999
  • DD(Decision Diagrams) is an efficient operational data structure for an optimal expression of boolean functions. In a graph-based synthesis using DD, the goal of optimization decreases representation space for boolean functions. This paper represents boolean functions using OPKFDD(Ordered Pseudo-Kronecker Functional Decision Diagrams) for a graph-based synthesis and is based on the number of nodes as the criterion of DD size. For a property of OPKFDD that is able to select one of different decomposition types for each node, OPKFDD is variable in its size by the decomposition types selection of each node and input variable order. This paper proposes a method for generating OPKFDD efficiently from the current BDD(Binary Decision Diagram) Data structure and an algorithm for minimizing one. In the multiple output functions, the relations of each function affect the number of nodes of OPKFDD. Therefore this paper proposes a method to decide the input variable order considering the above cases. Experimental results of comparing with the current representation methods and the reordering methods for deciding input variable order are shown.

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Storing Scheme based on Graph Data Model for Managing RDF/S Data (RDF/S 데이터의 관리를 위한 그래프 데이터 모델 기반 저장 기법)

  • Kim, Youn-Hee;Choi, Jae-Yeon;Lim, Hae-Chull
    • Journal of Digital Contents Society
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    • v.9 no.2
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    • pp.285-293
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    • 2008
  • In Semantic Web, metadata and ontology for representing semantics and conceptual relationships of information resources are essential factors. RDF and RDF Schema are W3C standard models for describing metadata and ontology. Therefore, many studies to store and retrieve RDF and RDF Schema documents are required. In this paper, we focus on some results of analyzing available query patterns considering both RDF and RDF Schema and classify queries on RDF and RDF Schema into the three patterns. RDF and RDF Schema can be represented as graph models. So, we proposed some strategies to store and retrieve using the graph models of RDF and RDF Schema. We can retrieve entities that can be arrived from a certain class or property in RDF and RDF Schema without a loss of performance on account of multiple joins with tables.

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A Survey research on Current Situation and Effectiveness of Performance Information in the Hang-Tag of Functional Outdoor Jacket (기능성 아웃도어 재킷의 행택을 통한 성능정보 제공 현황과 유용성 및 대안연구)

  • Lee, Eun Byol;Bang, Gi seong;Yoo, Shin Jung
    • Fashion & Textile Research Journal
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    • v.16 no.5
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    • pp.800-810
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    • 2014
  • In this study, the current status of product information of functional outdoor jackets in the hang-tags was investigated in perspective of consumer protection. Effectiveness and preferred alternatives to hang-tag information were also investigated. For the market survey, 1560 hang-tags from 676 functional outdoor jackets were investigated. For the effectiveness and preferred alternatives, 472 adults in their 20-60's were surveyed. The average number of hang-tags was 2.3 but 5.9% did not provide any product information. The contents included functional property of fabric; quality guarantee; brand introduction; product characteristics; instructions for care/usage; subsidiary material information, and they were different depending on end-use of jackets. Consumers strongly wanted explanations of the terms used in the hang-tag and could not accurately figure out the functions of the products from hang-tag information regardless of expression methods. The percentage of incorrect answer of 'figure/foreign language' method was extremely high. It is a noticeable feature of graph method that customers perceived that the graph was difficult to understand, but the percentage of correct answers was much higher than other methods, implying that graph method was possibly more useful at delivering accurate information to the customers who pursuit information. Customers strongly agreed to need of alternative methods and preferred an unified performance grade from selected functions based on the end-use of products. Customers also wanted to include the information of performance change after laundering. The results could provide practical insights to the consumers, companies, and the government to prepare proper guideline/policies for consumer protection.

A Folksonomy Ranking Framework: A Semantic Graph-based Approach (폭소노미 사이트를 위한 랭킹 프레임워크 설계: 시맨틱 그래프기반 접근)

  • Park, Hyun-Jung;Rho, Sang-Kyu
    • Asia pacific journal of information systems
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    • v.21 no.2
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    • pp.89-116
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    • 2011
  • In collaborative tagging systems such as Delicious.com and Flickr.com, users assign keywords or tags to their uploaded resources, such as bookmarks and pictures, for their future use or sharing purposes. The collection of resources and tags generated by a user is called a personomy, and the collection of all personomies constitutes the folksonomy. The most significant need of the folksonomy users Is to efficiently find useful resources or experts on specific topics. An excellent ranking algorithm would assign higher ranking to more useful resources or experts. What resources are considered useful In a folksonomic system? Does a standard superior to frequency or freshness exist? The resource recommended by more users with mere expertise should be worthy of attention. This ranking paradigm can be implemented through a graph-based ranking algorithm. Two well-known representatives of such a paradigm are Page Rank by Google and HITS(Hypertext Induced Topic Selection) by Kleinberg. Both Page Rank and HITS assign a higher evaluation score to pages linked to more higher-scored pages. HITS differs from PageRank in that it utilizes two kinds of scores: authority and hub scores. The ranking objects of these pages are limited to Web pages, whereas the ranking objects of a folksonomic system are somewhat heterogeneous(i.e., users, resources, and tags). Therefore, uniform application of the voting notion of PageRank and HITS based on the links to a folksonomy would be unreasonable, In a folksonomic system, each link corresponding to a property can have an opposite direction, depending on whether the property is an active or a passive voice. The current research stems from the Idea that a graph-based ranking algorithm could be applied to the folksonomic system using the concept of mutual Interactions between entitles, rather than the voting notion of PageRank or HITS. The concept of mutual interactions, proposed for ranking the Semantic Web resources, enables the calculation of importance scores of various resources unaffected by link directions. The weights of a property representing the mutual interaction between classes are assigned depending on the relative significance of the property to the resource importance of each class. This class-oriented approach is based on the fact that, in the Semantic Web, there are many heterogeneous classes; thus, applying a different appraisal standard for each class is more reasonable. This is similar to the evaluation method of humans, where different items are assigned specific weights, which are then summed up to determine the weighted average. We can check for missing properties more easily with this approach than with other predicate-oriented approaches. A user of a tagging system usually assigns more than one tags to the same resource, and there can be more than one tags with the same subjectivity and objectivity. In the case that many users assign similar tags to the same resource, grading the users differently depending on the assignment order becomes necessary. This idea comes from the studies in psychology wherein expertise involves the ability to select the most relevant information for achieving a goal. An expert should be someone who not only has a large collection of documents annotated with a particular tag, but also tends to add documents of high quality to his/her collections. Such documents are identified by the number, as well as the expertise, of users who have the same documents in their collections. In other words, there is a relationship of mutual reinforcement between the expertise of a user and the quality of a document. In addition, there is a need to rank entities related more closely to a certain entity. Considering the property of social media that ensures the popularity of a topic is temporary, recent data should have more weight than old data. We propose a comprehensive folksonomy ranking framework in which all these considerations are dealt with and that can be easily customized to each folksonomy site for ranking purposes. To examine the validity of our ranking algorithm and show the mechanism of adjusting property, time, and expertise weights, we first use a dataset designed for analyzing the effect of each ranking factor independently. We then show the ranking results of a real folksonomy site, with the ranking factors combined. Because the ground truth of a given dataset is not known when it comes to ranking, we inject simulated data whose ranking results can be predicted into the real dataset and compare the ranking results of our algorithm with that of a previous HITS-based algorithm. Our semantic ranking algorithm based on the concept of mutual interaction seems to be preferable to the HITS-based algorithm as a flexible folksonomy ranking framework. Some concrete points of difference are as follows. First, with the time concept applied to the property weights, our algorithm shows superior performance in lowering the scores of older data and raising the scores of newer data. Second, applying the time concept to the expertise weights, as well as to the property weights, our algorithm controls the conflicting influence of expertise weights and enhances overall consistency of time-valued ranking. The expertise weights of the previous study can act as an obstacle to the time-valued ranking because the number of followers increases as time goes on. Third, many new properties and classes can be included in our framework. The previous HITS-based algorithm, based on the voting notion, loses ground in the situation where the domain consists of more than two classes, or where other important properties, such as "sent through twitter" or "registered as a friend," are added to the domain. Forth, there is a big difference in the calculation time and memory use between the two kinds of algorithms. While the matrix multiplication of two matrices, has to be executed twice for the previous HITS-based algorithm, this is unnecessary with our algorithm. In our ranking framework, various folksonomy ranking policies can be expressed with the ranking factors combined and our approach can work, even if the folksonomy site is not implemented with Semantic Web languages. Above all, the time weight proposed in this paper will be applicable to various domains, including social media, where time value is considered important.