• The Journal of the Korea Contents Association
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• v.11 no.9
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• pp.54-62
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• 2011

This paper proposes both global and local mobility management (MM) scheme improved from Multi Protocol Label Switching (MPLS)-based Mobility Management scheme (MPLS-MOB) for seamless service in Next Generation Network (NGN). The proposed scheme adds local MM on the existing MPLS-MOB which supports global MM by processing handover signaling by 2.5 layer switching via Label Switch Path (LSP) of MPLS. We numerically analyze and verify that the proposed scheme has lower handover latency time than the existing ones, such as micro-MM methods using MPLS as well as MIP and an interworking scenario between PMIP and MIP.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2B
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• pp.143-150
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• 2009

In this paper, we propose a novel shadow clustering mechanism including a mobility estimation algorithm based on Gauss-Markov mobility model which analyses patterns of moving direction and speed of a mobile terminal respectively and a selection algorithm of the most suitable network for the requirements of mobile terminals. The proposed mechanism makes much less shadow cluster area than that of the legacy methods, and reduces unnecessary resource reservation. It is compared the proposed algorithm with traditional methods under various scenarios.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10b
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• pp.1267-1270
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• 2000

위성통신 시스템은 기존의 지상망이나 광 케이블 기술에 비해 통신 대역폭의 유연성과 다중 접속능력, 이동통신, 광역성, 멀티포인트 및 브로드캐스팅 등의 본래의 특징으로 인해 초고속정보통신망 구축에 중요한 역할을 하게 된다. 특히 OBP (On-Board Processing) 기술을 적용하면 기존 위성통신 탑재장치의 수동적인 중계 기능 이외에 복조/재변조, 부호/복호화 및 오류정정, 중계기 및 빔간의 상호 연결/절체 등의 새로운 기능이 추가되어 능동적인 중계를 가능하게 함으로써 통신 품질의 향상, 통신 링크의 전송 효율 개선, 전송 용량 증대 등의 장점을 갖고있다. OBP 탑재 위성 B-IDSN 중계망은 하나의 거대한 가상 ATM 교환기로 간주되고, 여러중계 지구국들중 목적 중계 지구국으로 패킷들을 직접 라우팅 할 수 있는 장점이 있다. 본 논문은 OBP 탑재 위성 B-ISDN 연동 프로토콜 연구를 수행하는 것으로서, 위성 B-ISDN 구조와 각 지구국별 신호 기능 및 B-IDSN 신호 시스템인 DSS2 계층 3 신호 프로토콜, B-ISUP 프로토콜, S-BISUP 프로토콜의 구조를 분석하였다. 또한 점-대-다지점을 위한 B-ISDN의 연결과 소유권 및 각각의 프로토콜에 대한 메시지와 프리미티브를 정의하여, 이를 토대로 OBP 탑재 위성 B-IDSN 연동 프로토콜의 기본 호 처리 절차를 설계 및 구현하고, 이를 테스트하였다.

• The Journal of the Korea Contents Association
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• v.13 no.3
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• pp.444-455
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• 2013

The purpose of this study is to explore the selection attributes for parents of children with language disability when choosing a clinic. The data collection was carried out in 3 steps: the preliminary survey, first open survey and second survey in AHP(Analytic Hierarchy Process). The subjects of were 252 in total. The results were as follows: First, The order of priority attributes in superior categories for parents of children with language disability when selecting a clinic were 'therapist-related attributes', 'program-related attributes' and 'physical-related attributes' in turn. The top 5 priority attributes in subcategories were 'therapist's academic background and major', 'ability to make a rapport', 'clinical experience and qualification of therapist', 'kindness and confidence' and 'counseling program for parents'. Second, The parents of preschoolers age 6 and younger chose 'clinical experience and qualification of therapist', 'counseling program for parents' and 'learning materials' for the most priority attributes, whereas the parents of students age from 7 to 12, considered 'therapist's academic background and major', 'clinical fee' and 'distance transport parking' more importantly to select a clinic. The results of this study provided preliminary data for successful planning of speech and language therapy.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.2
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• pp.238-247
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• 2023

Liquefied petroleum gas (LPG) is an attractive fuel for ships considering its current technology and economic viability. However, safety guidelines for LPG-fueled ships are still under development, and there have been no cases of applying LPG propulsion systems to small and medium-sized ships in Korea. The purpose of this study was to perform an objective risk assessment for the first marine LPG engine system and propose safe operational standards. First, hazard and operability (HAZOP) analysis was used to divide the engine system into five nodes, and 58 hazards were identified. To compensate for the subjectivity of qualitative evaluation using HAZOP analysis, fuzzy set theory was used, and additional risk factors, such as detectability and sensitivity, were included to compare the relative weights of the risk factors using a fuzzy analytical hierarchy process. As a result, among the five risk factors, those with a major impact on risk were determined to be the frequency and severity. Finally, the fuzzy technique for order of preference by similarity to ideal solution (TOPSIS) was applied to select the risk rank more precisely by considering the weights of the risk factors. The risk level was divided into 47 groups, and the major hazard during the operation of the engine system was found through the analysis to be gas leakage during maintenance of the LPG supply line. The technique proposed can be applied to various facilities, such as LPG supply systems, and can be utilized as a standard procedure for risk assessment in developing safety standards for LPG-powered ships.

• Journal of Korea Port Economic Association
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• v.28 no.2
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• pp.95-111
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• 2012

The service quality survey for the customers of Gwangyang container port has been done since 2005. It has been difficult to compare annual levels or rival ports because the calculation of weights among service dimensions that is the most important procedure of the assessment systems did not be founded. In particular, the calculation results by the Analytical Hierarchy Process that specializes in estimating the weights were very unstable and not comparable because they were fluctuated annually more than 90% for the specific item. The objective of this study is to support the establishment for new assessment system of service quality with cost- and time-effective tools at Gwangyang port. The confirmatory factor analysis methodology applied to 2007-2009 survey data from the customers of Gwangyang port can estimate ex-post weights to measure annually the stable service quality. The proposed methodology allows us to build the assessment system of more scientific and accurate service quality while reducing the survey items. By this study, a port company can measure accurately the quality of service and improve its competitiveness through being compared to previous periods and leading companies.

• Korean Security Journal
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• no.59
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• pp.161-188
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• 2019

Not much is known about the factors of North Korean refugees willingness to report crime. Based on the survey of 800 North Korean refugees living in the metropolitan area of South Korea, this study examined the theoretical factors influencing North Korean refugees' willingness of reporting crime. Focusing on the legal cynicism, procedural justice, and the behavior of law theory, this research verified that procedural justice model is most important in explaining their willingness to report crime. Variables under procedural justice model(i.e., perceived fairness of the law, confidence in the law, and perceived necessity of the law) were significant in an expected direction. On the other hand, most of the hypotheses based on social conditions derived from the five types of stratification, morphology, culture, organization, and social control presented by Donald Black (1974) showed no significant effects on the intent to report crime among North Korean refugees. Implications for research and policies were discussed based on the findings.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.12
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• pp.704-715
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• 2004

Recently, a single or multi processor system uses the hierarchical memory structure to reduce the time gap between processor clock rate and memory access time. A cache memory system includes especially two or three levels of caches to reduce this time gap. Moreover, one of the most important things In the hierarchical memory system is the hit rate in level 1 cache, because level 1 cache interfaces directly with the processor. Therefore, the high hit rate in level 1 cache is critical for system performance. A victim cache, another high level cache, is also important to assist level 1 cache by reducing the conflict miss in high level cache. In this paper, we propose the advanced high level cache management scheme based on the processor reuse information. This technique is a kind of cache replacement policy which uses the frequency of processor's memory accesses and makes the higher frequency address of the cache location reside longer in cache than the lower one. With this scheme, we simulate our policy using Augmint, the event-driven simulator, and analyze the simulation results. The simulation results show that the modified processor reuse information scheme(LIVMR) outperforms the level 1 with the simple victim cache(LIV), 6.7% in maximum and 0.5% in average, and performance benefits become larger as the number of processors increases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.445-453
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• 2017

The Korean government's recent R&D policy has focused on encouraging government-funded research institutes (GRIs) to develop mid-term, long-term, and large-scale R&D projects. It is necessary to prepare thoroughly for the new R&D strategy, but there is no systematic accumulation of planning expertise, and there has been continued demand for good examples of research planning. Therefore, this study analyzes the reports of preliminary feasibility for government R&D programs through a meta-analysis of detailed evaluation items and contents to help researchers enhance their project-planning ability. The evaluation items that can be applied to R&D planning for GRI were reviewed, and twelve detailed evaluation items were selected through content analysis. The results of this study could contribute to practical R&D project planning and the improvement of evaluations.

• Journal of Digital Contents Society
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• v.10 no.4
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• pp.543-550
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• 2009

In these days mobile handsets have come to be used at almost every user. The performance improvement of mobile devices and networks have made this trend possible. As a great variety of mobile applications are published, the necessity of running large-scale mobile applications becomes greater than before. To accomplish this, the existing researchers have developed mobile cluster computing libraries like Mobile-JPVM. In this paper, we implement a compute-intensive Animated GIF generating application and its cell phone viewer software using Mobile-JPVM library. We find out by the real execution of our softwares on the KTF handsets that they can sufficiently run on cellular phones. Our Animated GIF generator and its viewer are going to be commercially used for the mobile fashion advertisement systems.