• ETRI Journal
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• v.34 no.1
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• pp.142-145
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• 2012

The main challenge at present in constructing hierarchical identity-based encryption (HIBE) is to solve the trade-off between private-key size and ciphertext size. At least one private-key size or ciphertext size in the existing schemes must rely on the hierarchy depth. In this letter, a new hierarchical computing technique is introduced to HIBE. Unlike others, the proposed scheme, which consists of only two group elements, achieves constant-size private keys. In addition, the ciphertext consists of just three group elements, regardless of the hierarchy depth. To the best of our knowledge, it is the first efficient scheme where both ciphertexts and private keys achieve O(1)-size, which is the best trade-off between private-key size and ciphertext size at present. We also give the security proof in the selective-identity model.

• Journal of Korea Multimedia Society
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• v.21 no.12
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• pp.1417-1424
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• 2018

In order to improve the performance of image classifications using Convolutional Neural Networks (CNN), applying a category hierarchy to the classification can be a useful idea. However, the visual separation of object categories is very different according to the upper and lower category levels and highly uneven in image classifications. Therefore, it is doubtable whether the use of category hierarchies for classification is effective in CNN. In this paper, we have clarified whether the image classification using category hierarchies improves classification performance, and found at which level of hierarchy classification is more effective. For experiments we divided the image classification task according to the upper and lower category levels and assigned image data to each CNN model. We identified and compared the results of three classification models and analyzed them. Through the experiments, we could confirm that classification effectiveness was not improved by reduction of number of categories in a classification model. And we found that only with the re-training method in the last network layer, the performance of lower category classification was not improved although that of higher category classification was improved.

• Journal of Korea Multimedia Society
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• v.7 no.2
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• pp.283-291
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• 2004

Internet Service Subscribers Network has a new role of providing the various multimedia services to the home. However, there exist several types of distributed subscribers network using Asymmetric Digital Subscriber Line (ADSL), Very high-bit rate Digital Subscriber Line (VDSL), and Data Over Cable Service Interface Specifications (DOCSIS). The efficient and concentrated network management of those several distributed subscribers networks with resources require the general information model of network, which has abstract and conceptional managed objects independent of type of network and its equipment to manage the integrated subscriber network. This paper presents the general Internet subscribers network model of the managed object to manage that network in the form of integrated hierarchy This paper adopts the object-oriented development methodology with UML and designs and implements the integrated subscribers NMS of cable data network and VDSL network as examples of the subscriber networks.

• Journal of Internet Computing and Services
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• v.5 no.3
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• pp.87-98
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• 2004

There are several types of distributed subscribers network using Asymmetric Digital Subscriber Line (ADSL), Very high-bit rate Digital Subscriber Line (VDSL), and Data Over Cable Service Interface Specifications (DOCSIS), The efficient and concentrated network management of those several distributed subscribers networks and resources require the general information model of network, which has abstract and conceptional managed objects independent of type of network and its equipment to manage the integrated subscriber network, This paper presents the general Internet subscribers network modeling framework using RM-ODP (Reference Model Open Distributed Processing) to manage that network In the form of integrated hierarchy, This paper adopts the object-oriented development methodology with UML (Unified Modeling Language) and designs and implements the HFC network of DOCSIS as an example of the subscriber network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.34-36
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• 2022

In the existing text sentiment analysis models, the entire text is usually directly modeled as a whole, and the hierarchical relationship between text contents is less considered. However, in the practice of sentiment analysis, many texts are mixed with multiple emotions. If the semantic modeling of the whole is directly performed, it may increase the difficulty of the sentiment analysis model to judge the sentiment, making the model difficult to apply to the classification of mixed-sentiment sentences. Therefore, this paper proposes a sentiment analysis model BHGCN that considers the text hierarchy. In this model, the output of hidden states of each layer of BERT is used as a node, and a directed connection is made between the upper and lower layers to construct a graph network with a semantic hierarchy. The model not only pays attention to layer-by-layer semantics, but also pays attention to hierarchical relationships. Suitable for handling mixed sentiment classification tasks. The comparative experimental results show that the BHGCN model exhibits obvious competitive advantages.

• The Transactions of the Korea Information Processing Society
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• v.4 no.10
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• pp.2533-2543
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• 1997

It is necessary to understand and apply the concept of Quality of Service(QoS) for the objective selection among the computer network equipment. Because ITU-T E.800 recommendation covers the service quality of provider's viewpoint and the satisfaction of user, it can be used to evaluate and select the product of computer network systems. This paper is concerned with the development of an evaluation model using QoS and software tool for selection of the most suitable LAN switch. We apply the Analytic Hierarchy Process(AHP) method of Saaty which has been in a multiple criteria framework for an effective group decision process to the selection of LAN switch. The sample data are collected and processed from a questionnaire of professionals in the network field. And we implement a prototype tool for the selection of LAN switch according to the suggested selection model and analyse the result. The result of our research is expected to be a useful tool for decision making to evaluate and select the LAN switch and also can be applied to the decision making of evaluation and selection related to the product of computer network with QoS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1B
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• pp.15-30
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• 2000

The important considerations in the design of fiber-optic networks are reliability and survivability preparing against a failure. The SDH(Synchronous Digital Hierarchy), the international standard of optical transmission, offers several network reconfiguration methods that enable network to be automatically restored from failure. One of the methods is the SHR(Self Healing Ring), which is a ring topology system. Most network providers have constructed their backbone networks with SHR architecture since it can provide survivability economically. The network architecture has eventually evolved into a multi-ring network comprised of interconnected rings. This paper addresses multi-ring network design problems is to minimize ring-construction cost. This problem can be formulated with MIP(mixed integer programming) model. However, it is difficult to solve the model within reasonable computing time on a large scale network because the model is NP-complete. Furthermore, in practice we should consider the problem of routing demands on rings to minimize total cost. This routing problem involves multiplex bundling at the intermediate nodes. A family of heuristic algorithms is presented for this problem. These algorithms include gateway selection and routing of inter-ring demands as well as load balancing on single rings. The developed heuristic algorithms are applied to some network provider's regional and long-distance transmission networks. We show an example of ring design and compare it with another ring topology design. Finally, we analysis the effect bundling.

• ETRI Journal
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• v.36 no.4
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• pp.572-580
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• 2014

Mobile operators in saturated markets increasingly favor mobile network sharing (MNS) over facility-based competition. Previous research examining MNS primarily focused on its positive effects, while the negative effects were largely overlooked. This study proposes a decision-making model using an analytic hierarchy process technique to evaluate decision-making criteria among various types of MNS policies. The decision-making model was applied to Wireless Broadband services in Korea to determine the relative importance of both positive and negative evaluation criteria and preference among multiple types of MNS policies. Positive evaluation criteria (that is, efficiency) were far greater in importance than negative evaluation criteria (that is, competition harm). The preference for adopting MNS among five alternative approaches was also revealed. The study findings offer immediate policy insights in Korea and provide a decision-making framework for policy makers in other countries to utilize.

• Journal of Korean Society of Rural Planning
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• v.15 no.1
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• pp.47-59
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• 2009

The aim of this study is to analyze the green-tourism centrality considering spatial interaction using Gravity Model and social network method. The degree centrality and prestige centrality were applied as green-tourism centrality index. The rural amenity resources and human resources were counted as attraction factors, and a distance among villages was used as friction factor in gravity model. The weights of rural tourism amenity resources were calculated using the analytic hierarchy process(AHP) method and applied to evaluate green-tourism potentiality. The distance was measured with the shortest path among villages using geographic information system(GIS) network analysis. The spatial interaction from gravity model were employed as link weights between nodal points; a pair villages. Using the spatial interaction, the degree-centrality and prestige-centrality indices were calculated by social network analysis and demonstrated possibility of developing integrated green-tourism region centered on high centrality villages.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.11
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• pp.943-954
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• 2000

Fieldbus is the lowest level industrial network in the communication hierarchy of factory automation and distributed process control systems. Data generated from field devices are largely divided into three categories : time-critical, periodic and time-available data. Because these data share one fieldbus medium, it needs a method that allocates these data to the bandwidth-limited fieldbus medium. This paper introduces an implementation method of bandwidth allocation scheme on PROFIBUS. In order to implement bandwidth allocation scheme on PROFIBUS, the following functions need to be supplemented on the FDL(Fieldbus Datalink Layer) protocol: (i) separation of medium bandwidth into periodic and non-periodic intervals, (ii) synchronization of node timers over a local link. In order to examine the validity of bandwidth allocation scheme on PROFIBUS, this paper develops an experimental model of a network system. The results obtained from the experimental model show that the bandwidth allocation scheme satisfies the performance requirement of time-critical, periodic and time-available data.