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[Keyword] information network(8hit)

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  • Heterogeneous Graph Contrastive Learning for Stance Prediction

    Yang LI  Rui QI  

     
    PAPER-Natural Language Processing

      Pubricized:
    2022/07/25
      Vol:
    E105-D No:10
      Page(s):
    1790-1798

    Stance prediction on social media aims to infer the stances of users towards a specific topic or event, which are not expressed explicitly. It is of great significance for public opinion analysis to extract and determine users' stances using user-generated content on social media. Existing research makes use of various signals, ranging from text content to online network connections of users on these platforms. However, it lacks joint modeling of the heterogeneous information for stance prediction. In this paper, we propose a self-supervised heterogeneous graph contrastive learning framework for stance prediction in online debate forums. Firstly, we perform data augmentation on the original heterogeneous information network to generate an augmented view. The original view and augmented view are learned from a meta-path based graph encoder respectively. Then, the contrastive learning among the two views is conducted to obtain high-quality representations of users and issues. Finally, the stance prediction is accomplished by matrix factorization between users and issues. The experimental results on an online debate forum dataset show that our model outperforms other competitive baseline methods significantly.

  • Semantic Shilling Attack against Heterogeneous Information Network Based Recommend Systems

    Yizhi REN  Zelong LI  Lifeng YUAN  Zhen ZHANG  Chunhua SU  Yujuan WANG  Guohua WU  

     
    PAPER

      Pubricized:
    2021/11/30
      Vol:
    E105-D No:2
      Page(s):
    289-299

    The recommend system has been widely used in many web application areas such as e-commerce services. With the development of the recommend system, the HIN modeling method replaces the traditional bipartite graph modeling method to represent the recommend system. But several studies have already showed that recommend system is vulnerable to shilling attack (injecting attack). However, the effectiveness of how traditional shilling attack has rarely been studied directly in the HIN model. Moreover, no study has focused on how to enhance shilling attacks against HIN recommend system by using the high-level semantic information. This work analyzes the relationship between the high-level semantic information and the attacking effects in HIN recommend system. This work proves that attack results are proportional to the high-level semantic information. Therefore, we propose a heuristic attack method based on high-level semantic information, named Semantic Shilling Attack (SSA) on a HIN recommend system (HERec). This method injects a specific score into each selected item related to the target in semantics. It ensures transmitting the misleading information towards target items and normal users, and attempts to interfere with the effect of the recommend system. The experiment is dependent on two real-world datasets, and proves that the attacking effect is positively correlate with the number of meta-paths. The result shows that our method is more effective when compared with existing baseline algorithms.

  • Evolution and Future of Information Networks Open Access

    Tohru ASAMI  Katsunori YAMAOKA  Takuji KISHIDA  

     
    INVITED SURVEY PAPER-Network

      Pubricized:
    2017/03/22
      Vol:
    E100-B No:9
      Page(s):
    1595-1605

    This paper looks at the history of research in the Technical Committee on Information Networks from the time of its inception to the present and provides an overview of the latest research in this area based on the topics discussed in recent meetings of the committee. It also presents possible future developments in the field of information networks.

  • Sensitivity Analysis in Optimal Design for Distributed File Allocation Systems

    Akiko NAKANIWA  Masaki ONISHI  Hiroyuki EBARA  Hiromi OKADA  

     
    PAPER-Software Platform

      Vol:
    E84-B No:6
      Page(s):
    1655-1663

    In distributed network systems, it is one of the most important problems how to assign the files to servers in view of cost and delay. It is obvious that there is a trading-off relationship between costs and delays in these systems. In order to evaluate the optimization that the total cost is minimized subject to the total delay, we have presented the Optimal File Allocation Model as 0-1 integer programming, and have investigated the general characteristics in distributed systems. In this model, we have introduced many cost and delay parameters to evaluate the total cost and delay in the system more exactly. In constructing practical systems, it is necessary to investigate the weight and the contribution of each parameter to the total cost. It is very useful to show how to estimate cost and delay parameters on the basis of this analysis. In this paper, we analyze the sensitivity of these parameters and make clear the influence between principal parameters.

  • A Study of Minimum-Cost Tree Problem with Response-Time Bound in Information Network

    Norihiko SHINOMIYA  Hiroshi TAMURA  Hitoshi WATANABE  

     
    PAPER-Graphs and Networks

      Vol:
    E84-A No:2
      Page(s):
    638-646

    This paper deals with a study of a problem for finding the minimum-cost spanning tree with a response-time bound. The relation of cost and response-time is given as a monotonous decreasing and convex function. Regarding communication bandwidth as cost in an information network, this problem means a minimum-cost tree shaped routing for response-time constrained broadcasting, where any response-time from a root vertex to other vertex is less than a given time bound. This problem is proven to be NP-hard and consists of the minimum-cost assignment to a rooted tree and the minimum-cost tree finding. A nonlinear programming algorithm solves the former problem for the globally optimal solution. For the latter problem, different types of heuristic algorithms evaluate to find a near optimal solution experimentally.

  • File Allocation Designs for Distributed Multimedia Information Networks

    Akiko NAKANIWA  Hiroyuki EBARA  Hiromi OKADA  

     
    PAPER-Heterogeneous Multimedia Servers

      Vol:
    E81-B No:8
      Page(s):
    1647-1655

    In this paper, we study the optimal allocation of multimedia files in distributed network systems. In these systems, the files are shared by users connected with different servers geographically separated, and each file must be stored in at least one of servers. Users can access any files stored in any servers connected with high-speed communication networks. Copies of the files accessed frequently are to be stored in several servers that have databases. So, it is one of the most important problems how to assign the files to servers in view of costs and delays. Considering these problems in heterogeneous network environments, we present a new system model that covers wide range of multimedia network applications like VOD, CALS, and so on. In these systems, it is obvious that there is trading-off relationship between costs and delays. Our objective is to find the optimal file allocation such that the total cost is minimized subject to the total delay. We introduce a 0-1 integer programming formulation for the optimization problem, and find the optimal file allocation by solving these formulae.

  • Quantitative Study of Human Behavior in Virtual Interview Sessions for the Development of the Hyper Hospital--A Network Oriented Virtual Reality Based Novel Medical Care System--

    Atsuya YOSHIDA  Takami YAMAGUCHI  Kiyoyuki YAMAZAKI  

     
    PAPER

      Vol:
    E77-D No:12
      Page(s):
    1365-1371

    The Hyper Hospital" is a novel medical care system which will be constructed on an electronic information network. The human interface of the Hyper Hospital based on the modern virtual reality technology is expected to enhance patients' ability to heal by providing computer-supported on-line visual consultations. In order to investigate the effects and features of on-line visual consultations in the Hyper Hospital, we conducted an experiment to clarify the influence of electronic interviews on the talking behavior of interviewees in the context of simulated doctor-patient interactions. Four types of distant-confrontation interviews were made with voluntary subjects and their verbal and non-verbal responses were analyzed from the behavioral point of view. The types of interviews included three types of electronic media-mediated interviews and one of a live face to face interview. There was a tendency in the media-mediated interviews that both the latency and the duration of interviewees' utterances in answering questions increased when they were compared with those of live face to face interviews. These results suggest that the interviewee became more verbose or talkative in the media-mediated interviews than in the live interviews. However, the interviewee's psychological tension was generally augmented in the media-mediated interviews, which was suggested by the delay of the initiation of conversations as compared to the conventional face-to-face interviews. We also discuss the applicability of media-mediated interviews by an electronic doctor which we are studying as a functional unit of our Hyper Hospital, a network based virtual reality space for medical care.

  • Fundamental Analysis on Quantum Interconnections in a 2DEG System

    Yujiro NARUSE  

     
    PAPER

      Vol:
    E76-C No:9
      Page(s):
    1362-1366

    A quantum interconnection scheme by controlling the Coulomb interaction between ballistic electrons is proposed in which 2DEG (2 dimensional electron gas) plays the role of an interconnection medium. This concept brings up new possibilities for the interconnection approach in various fields such as parallel processing, telecommunications switching, and quantum functional devices. Cross-over interconnection, address collision, and address selection in a quantum information network system were analyzed as the first step. The obtained results have shown that the interconnection probability can be controlled by the velocity and timing of the ballistic electron emission from the emitter electrode. The proposed interconnection scheme is expected to open up a new field of quantum effect integrated circuits in the 21st century.