• Journal of Korea Multimedia Society
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• v.10 no.2
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• pp.147-169
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• 2007

Semantic Web Services Discovery matches between users' requirements and the ontological description of Web Services. However, concepts of an ontology can be interpreted differently according to a point of view. Previous works are limited in interpreting concepts. Since they lack a precise scheme of describing the advertisements and requirements of services and users, respectively, and even do not support a sophisticated matching, semantic mismatches may occur. This paper presents a sophisticated method of discovering Web services. The proposed method facilitates specifying semantics precisely and flexibly based on a proposed integrated concept model. Additionally, more sophisticated discovery is supported by computing complex matchings with many-to-many relationships. Experimental results show that the proposed method performs more efficiently for various kinds of user requests, compared with previous works.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.12
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• pp.2702-2707
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• 2012

In the rapid growth of cities, road has heavy traffic and many buildings are under constructions. These kinds of environments make more difficulty for a person who is visually handicapped to walk comfortable. To alleviate the problem, we introduce Navigation System to help walking for Visually Impaired Person. It follows, service center give instant real time monitoring to visually impaired person for their convenient by this system. This Navigation System has GPS, Camera, Audio and Wi-Fi(wireless fidelity) available. It means that GPS location and Camera image information can be sent to service center by Wi-Fi network. To be specific, transmitted GPS location information enables service center to figure out the visually impaired person's whereabouts and mark the location on the map. By delivered Camera image information, service center monitors the visually impaired person's view. Also, they can offer live guidance to visually impaired person by equipped Audio with live talking. To sum up, Android based Portable Navigation System is a specialized navigation system that gives practical effect to realize more comfortable walking for visually impaired person.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.7
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• pp.167-176
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• 2019

Recently, as the types of services that can be enjoyed in mobile telecommunication networks such as social networks and video streaming are increasing, mobile users(MUs) can access mobile contents easily by consuming mobile data. However, under a mobile telecommunication environment, MUs have to pay a high data fee to a network service provider(SP) in order to enjoy contents. The 'data sponsor' technique, introduced as a way to solve this problem, has attracted attention as a breakthrough method for enhancing contents accessibility of MUs. In this paper, we propose an algorithm that determines the optimal discount rate through the Stackelberg game in the data sponsor environment. We also propose an algorithm to design edge caching, which caches highly popular content for MUs on edge server, through many-to-many matching game. Simulation results clearly indicate that the profit for CP's content consumption is improved by about 6~11%, and the profit of CP according to the ratio of edge caching is improved by about 12% than the other existing schemes under data sponsor environment.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.5 no.3
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• pp.27-45
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• 2010

It is strongly believed that multicast will become one of the most promising services on internet for the next generation. Multicast service can be deployed either on network-layer or application-layer. IP multicast (network-layer multicast) is implemented by network nodes (i.e., routers) and avoids multiple copies of the same datagram on the same link. Despite the conceptual simplicity of IP multicast and its obvious benefits, it has not been widely deployed since there remain many unresolved issues. As an alternative to IP multicast, overlay multicast (application-layer multicast) implements the multicast functionality at end hosts rather than routers. This may require more overall bandwidth than IP multicast because duplicate packets travel the same physical links multiple times, but it provides an inexpensive, deployable method of providing point-to-multipoint group communication. In this paper we develop an efficient method applied greedy algorithm for solving two models of overlay multicast routing protocol that is aimed to construct MDST (Minimum Diameter Spanning Tree : minimum cost path from a source node to all its receivers) and MST (Minimum Spanning Tree : minimum total cost spanning all the members). We also simulate and analyze MDST and MST.

• 한국벤처창업학회:학술대회논문집
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• 2010.08a
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• pp.71-89
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• 2010

It is strongly believed that multicast will become one of the most promising services on internet for the next generation. Multicast service can be deployed either on network-layer or application-layer. IP multicast (network-layer multicast) is implemented by network nodes (i.e., routers) and avoids multiple copies of the same datagram on the same link. Despite the conceptual simplicity of IP multicast and its obvious benefits, it has not been widely deployed since there remain many unresolved issues. As an alternative to IP multicast, overlay multicast (application-layer multicast) implements the multicast functionality at end hosts rather than routers. This may require more overall bandwidth than IP multicast because duplicate packets travel the same physical links multiple times, but it provides an inexpensive, deployable method of providing point-to-multipoint group communication. In this paper we develop an efficient method applied greedy algorithm for solving two models of overlay multicast tree building problem that is aimed to construct MDST (Minimum Diameter Spanning Tree : minimum cost path from a source node to all its receivers) and MST (Minimum Spanning Tree : minimum total cost spanning all the members). We also simulate and analyze MDST and MST.

• Journal of Korea Multimedia Society
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• v.8 no.5
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• pp.660-669
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• 2005

In this paper 10Mbps master-slave based PLC modems are tested for measuring and analyzing both network and application level performances in the general buildings. The devices under test consist of one master PLC modem and three slave modems. The selected parameters for inspecting the performances are throughput, latency and frame loss rate from the RFC 2544, and one-to-many and many-to-one throughput from the RFC 2285. The results of the performance test show that the PLC modems have Performed better in data transmission when the frame size is increased and the transmission speed is decreased. It is expected that these results will be useful to analyze the effect of noise sources when compared to the performance test under the noiseless environments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.171-173
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• 2022

The 4th industrial revolution technology is developing people's lives more efficiently. GIS provided on the Internet services such as traffic information and time information makes people getting more quickly to destination. National geographic information service(NGIS) and each local government are making basic data to investigate SOC accessibility for analyzing optimal point. To construct the shortest distance, the accessibility from the starting point to the arrival point is analyzed. Applying road network map, the starting point and the ending point, the shortest distance, the optimal accessibility is calculated by using Dijkstra algorithm. The analysis information from multiple starting points to multiple destinations was required more than 3 steps of manual analysis to decide the position for the optimal point, within about 0.1% error. It took more time to process the many-to-many (M×N) calculation, requiring at least 32G memory specification of the computer. If an optimal proximity analysis service is provided at a desired location more versatile, it is possible to efficiently analyze locations that are vulnerable to business start-up and living facilities access, and facility selection for the public.