• Journal of Intelligence and Information Systems
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• v.14 no.2
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• pp.63-82
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• 2008

Recommendation systems are widely used to help deal with the problem of information overload. Over the past decades, a variety of recommendation systems have been developed as the amount of information in the world increases far more quickly than our ability to process it. This paper aims to analyze existing developed recommendation systems, provide systemic review, and present some basic issues on improvement action. Through this, we also suggest useful implications for better recommendation systems and give some ideas to recommendation system developers to improve their system. Especially, this study focuses on researches on recommendation system. In our research, we analyze the studies along with four different keys dimensions : their domain, objective, underlying model, and evaluation method of recommendation systems and portray the results as statistics or statistical graphics or table form.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.11
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• pp.2597-2615
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• 2013

This paper proposes a dynamic downlink load control scheme that jointly employs dynamic load threshold management and virtual coverage management schemes to reduce the degree of performance degradation due to traffic overload in two-tier femtocell networks. With the proposed scheme, the downlink load in a serving macrocell is controlled with a load threshold which is adjusted dynamically depending on the varying downlink load conditions of neighboring macrocells. In addition, traffic overloading is alleviated by virtually adjusting the coverage of the overloaded serving macrocell, based on the adjusted load threshold of the serving macrocell. Simulation results show that the proposed scheme improves the performance of two-tier femtocell networks in terms of the outage probability and sum throughput. This improvement is significantly increased with appropriate values of load thresholds and with an intermediate-level adjustment of the virtual coverage area (i.e., handover hysteresis margin: HOM). Furthermore, the proposed scheme outperforms both a previously proposed load control scheme with a static load threshold and the LTE system without a HOM adjustment.

• Knowledge Management Research
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• v.10 no.3
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• pp.17-33
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• 2009

The emergence of the Internet shopping agent enabled consumers to enjoy Internet shopping more easily and quickly. Especially, the role of Internet shopping agent is becoming more important following the information overload trend on the Internet in that the consumers can promptly obtain information about a certain product and its price among countless items on the Internet. As a result, consumers can now enjoy shopping more easily, compared to the offline shopping which requires a lot of efforts in comparing the products and purchasing them. Since the Internet shopping agents collect extensive information about the products' price, delivery period, detailed characteristics, etc., and present a comparison table containing the information to the consumers, the consumers can shop more quickly at lower price using such shopping agents. However, it has not been sufficiently studied about how the various functions of shopping agents actually support consumers' purchase decision making procedure in everyday life, and if they do, in which stages they play a supporting role in consumers' purchase decision making system. Therefore, this study conducts an empirical analysis on the role of the Internet shopping agents in the purchase decision making process of the consumers, considering the Internet shopping agent as a decision making supporting system. Moreover, it analyzes how the effects of the Internet shopping agent differs according to the consumers' knowledge level about the products.

• Journal of Internet Computing and Services
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• v.1 no.1
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• pp.27-34
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• 2000

Recently, the use of Geographic Information System in each field of our society is on the increase according to the development of the Internet. But, thereis a problem of the user access latencies, the network traffic, and the server overload in Internet Geographic Information System because spatial data are transferred in large volumes. In this paper, we propose a cache algorithm on client side to solve the above problems. The proposed algorithm demonstrates the performance improvement over known studies by utilizing unit time and spatial proximity. In addition, this paper conducts a performance evaluation to measure the improvement in algorithm efficiency and analyzes the results of the performance evaluation. When spatial data queries are conducted, according to our performance evaluation, hit rate has been improved over the existing algorithms.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.8
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• pp.3683-3703
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• 2018

Wireless sensor networks (WSNs) consist of set of sensor nodes. These sensor nodes are deployed in unattended area which are able to sense, process and transmit data to the base station (BS). One of the primary issues of WSN is energy efficiency. In many existing clustering approaches, initial centroids of cluster heads (CHs) are chosen randomly and they form unbalanced clusters, results more energy consumption. In this paper, an energy efficient clustering protocol to prevent unbalanced clusters based on firefly and midpoint algorithms called EEC-FM has been proposed, where midpoint algorithm is used for initial centroid of CHs selection and firefly is used for cluster formation. Using residual energy and Euclidean distance as the parameters for appropriate cluster formation of the proposed approach produces balanced clusters to eventually balance the load of CHs and improve the network lifetime. Simulation result shows that the proposed method outperforms LEACH-B, BPK-means, Park's approach, Mk-means, and EECPK-means with respect to balancing of clusters, energy efficiency and network lifetime parameters. Simulation result also demonstrate that the proposed approach, EEC-FM protocol is 45% better than LEACH-B, 17.8% better than BPK-means protocol, 12.5% better than Park's approach, 9.1% better than Mk-means, and 5.8% better than EECPK-means protocol with respect to the parameter half energy consumption (HEC).

• Journal of Digital Convergence
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• v.16 no.7
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• pp.97-105
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• 2018

The fourth industrial revolution is expected to bring about great changes in information technology sector and create a variety of jobs. However, the psychological anxiety of IT staff is increasing due to stress and uncertainty created by the new technologies. Accordingly, researchers examined how professional identity moderate the effect of job stress of system maintenance staff on emotion exhaustion. For empirical studies, data was collected from 160 employees responsible for managing and supporting IS, and the hypothesis was verified using SPSS 21. The analysis results showed that role conflicts, role ambiguity, and qualitative work overload, which are components of job stress, have affected the emotion exhaustion. Professional identity had a moderating effect the relationship between qualitative work overload and emotion exhaustion. On the other hand, professional identity did not moderate the relationship between role conflict and emotion exhaustion, role ambiguity and emotion exhaustion. As professional identity lessen the psychological burden and emotion exhaustion of introducing new technologies, organizations need to provide support to enhance professional identity for system maintenance staff.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.301-308
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• 2005

According to banking online transaction grows very rapidly, guarantee validity about business transaction has more meaning. To offer guarantee validity about banking online transaction efficiently, certificate status verification system is required that can an ieai-time offer identity certification, data integrity, guarantee confidentiality, non-repudiation. Existing real-time certificate status verification system is structural concentration problem generated that one node handling all transactions. And every time status verification is requested, network overload and communication bottleneck are occurred because ail useless informations are transmitted. it does not fit to banking transaction which make much account of real response time because of these problem. To improve problem by unnecessary information and structural concentration when existing real-time certificate status protocol requested , this paper handle status verification that break up inspection server by domain. This paper propose the method of real~time certificate status verification that solves network overload and communication bottleneck by requesting certification using really necessary Reduction information to certification status verification. And we confirm speed of certificate status verification $15\%$ faster than existing OCSP(Online Certificate Status Protocol) method by test.

• Journal of Korea Multimedia Society
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• v.18 no.9
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• pp.1091-1097
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• 2015

Internet-of-Things (IoT) becomes one of the most promising future paradigms, which foresees enormous amounts of interoperable things and heterogeneous services. The goal of IoT is to enable all things connected and brings all kinds information and services to people. However, such a great deal of information may lead to cognitive overload or restrain in productivity of people. Thus, it is a necessity to build intelligent mechanisms to assist people in accessing the information or services they needed in a proactive manner. Most of previous related mechanisms are built on well-defined web services and lack of consideration of constrained resources. This paper suggests a services composition method by adapting a hierarchical model, which is a graph-based model composed of four layers: Context Layer, Event Layer, Service Layer and Device Layer. With a such multi-layer graph, service composition can be achieved by the iteration of layer by layer. Then, to evaluate the effectiveness of this proposed hierarchical model, a real-life emergency response dataset is applied and the experimental results are composed with the general probabilistic method and indicate that the proposed method is help for compositing multiple services while considering given context and constrained resources.

• Proceedings of the Korea Association of Information Systems Conference
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• 2000.05a
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• pp.107-113
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• 2000

최근 인터넷 사용 증가는 물론 그에 따른 인터넷 사이트의 증가가 가히 폭발적이라고 할 수 있다. 전자상거래도 인터넷 사용증가에 힘입어 더욱 증가 추세에 있으며 관광산업 또한 예외는 아니다. 호텔에서도 웹사이트를 구축하여 온라인 예약과 각종 서비스에 필요한 정보를 제공하고 있으며 점차 온라인 예약이 증가추세이다. 하지만 인터넷 웹사이트의 급격한 증가는 풍부하고 다양한 정보를 제공한다는 긍정적인 면과 함께 정보과다(information overload)로 인해 정보 검색 등에 많은 시간과 비용이 요구되는 문제를 낳았다. 위와 같은 환경에서 사용자를 대신하여 원하는 정보를 찾아주는 역할을 수행하는 에이전트(agent)의 개념이 도입되었다. 현재 전자상거래 분야에서 활용 중인 에이전트는 구매자가 직접 판매자와 접촉하여 자신에게 필요한 여러 가지정보를 얻고 필요에 따라서는 협상 등을 진행한 후 최종 거래를 성사시키는 ‘사람과 사람간의 일 대 일 거래 과정’중 일부분만을 지원하고 있는 실정이다. 이와 같은 현존 에이전트의 문제점을 보완하기 위해서 구매자와 판매자를 대표하는 에이전트를 개발하고 이들 에이전트간의 직접적인 정보교환, 가격협상 및 이를 바탕으로 한 의사결정까지의 거래 모델을 수립하는 것이 필요하다고 인식된다. 따라서 본 연구는 인터넷상에서 구매자와 판매자간의 거래를 대행하는 인터넷 다중 에이전트(Internet Multi-Agents)의 개발을 위한 개념적 거래 모델을 연구하고, 이를 호텔 예약 분야에 응용하기 위한 각 에이전트의 필요 조건 및 기능을 제시하고자 한다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.365-370
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• 2004

The integration of intelligent devices, devices-level networks, and software into motor control systems can deliver improved diagnostics, fast warnings for increased system reliability, design flexibility, and simplified wiring. Remote access to motor-control information also affords an opportunity for reduced exposure to hazardous voltage and improved personnel safety during startup and trouble-shooting. This paper presents LonWorks fieldbus networked intelligent induction control system architecture. Experimental bed system with two inverter motor driving system for controlling 1.5kW induction motor is configured for LonWorks networked intelligent motor control. In recent years, MCCs have evolved to include component technologies, such as variable-speed drives, solid-state starters, and electronic overload relays. Integration was accomplished through hardwiring to a programmable logic controller (PLC) or distributed control system (DCS). Devicelevel communication networks brought new possibilities for advanced monitoring, control and diagnostics. This LonWorks network offered the opportunity for greatly simplified wiring, eliminating the bundles of control interwiring and corresponding complex interwiring diagrams. An intelligent MCC connected in device level control network proves users with significant new information for preventing or minimizing downtime. This information includes warnings of abnormal operation, identification of trip causes, automated logging of events, and electronic documentation. In order to show the application of the multi-motors control system, the prototype control system is implemented. This paper is the first step to drive multi-motors with serial communication which can satisfy the real time operation using LonWorks network.