• 한국군사과학기술학회지
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• 제22권5호
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• pp.654-666
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• 2019

The tactical network has several different characteristics compared with commercial internet network such as hierarchical topology, dynamic topology changing and wireless link based connectivity. For considering IP mobility management in the tactical network, current mobility management using Mobile IP(MIP) is not suitable with some reasons such as non-optimal routing paths and single point of failure. Proxy Mobile IP(PMIP) which supporting network-based mobility in hierarchical manner can provide optimal routing path in the tactical network environment, but centralized anchor is still remained a threat to the stability of the tactical network which changes its topology dynamically. In this paper, we propose PMIP-based distributed mobility management for the tactical network environment. From our design, routing paths are always configured in optimized way, as well as path is recovered quickly when the mobility anchor of user is failed. From numerical analysis, comparing to other mobility scheme, result shows that the proposed scheme can reduce packet transmission cost and latency in tactical network model.

• 한국CDE학회논문집
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• 제19권4호
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• pp.316-323
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• 2014

This paper proposes the 3D modeling and simulation technique for predicting the integrated performance of combat vehicle. To consider the practical driving and firing condition of a combat vehicle, the full vehicle model, which can define the six degrees-of-freedom of vehicle motion and various firing angles, is developed. The critical design parameters such as the stiffness and damping coefficient of suspension system are applied to construct the analysis model of vehicle. A simple ballistic model, which incorporates the empirical interior ballistic model and the point mass trajectory model, is built to estimate the firing range and the firing recoil force. To predict the integrated performance and analyze the effect of system parameters, MATLAB/SIM-ULINK model of a combat vehicle for performing the real time simulation is also developed. Several simulation tests incorporating the road bump and the firing recoil force are presented to confirm the effectiveness of the proposed vehicle model.

• 경영과정보연구
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• 제36권2호
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• pp.239-260
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• 2017

본 연구는 혁신기술에 대한 사회적 수용의 관점에서 스마트 모빌리티(smart mobility)의 수용에 미치는 영향요인을 탐색하였다. 혁신기술의 사회적 수용과 확산에 관한 이론고찰을 통해 혁신-수용에 미치는 영향요인, 지각된 유용성의 인식과 수용의도에 미치는 일련의 과정에 대한 구조방정식 모형을 설정하고, 이를 실증적으로 분석하였다. 분석에 필요한 자료는 2016년 8월 1일에서 12일 사이에 설문을 통해 수집하였으며, 수집된 534개의 설문이 분석에 이용되었다. 실증분석결과, 적합성과 상대적 이점은 지각된 유용성을 매개로 스마트 모빌리티의 사회적 수용에 통계적으로 유의한 정(+)의 영향을 미쳤으나, 의사소통은 부(-)의 영향을 미치는 것으로 나타났다. 복잡성과 서비스품질은 통계적으로 유의한 영향을 미치지 못하는 것으로 나타났다. 본 연구의 결과에 기초하여 스마트 모빌리티의 사회적 수용과 관련된 시사점을 제공하였으며, 본 연구의 한계점과 이를 극복하기 위한 향후 연구방향도 제시하였다.

• 지역연구
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• 제39권3호
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• pp.49-63
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• 2023

본 연구는 지역노동시장 수준에서 청년층 임금근로자의 직업이동 패턴을 탐색하고, 개별 근로자 수준 및 지역노동시장 수준 특성이 직업이동에 어떠한 영향을 미치는지에 대해 실증 분석했다. 분석을 위한 자료로는 『청년패널2007』 4-14차년도(2010-2020년), 『재직자조사』 원자료, 『지역별고용조사』 등을 활용했으며, 위계적 선형모형을 응용하여 근로자 개인 수준 및 지역노동시장 수준 한계효과를 추정했다. 분석 결과에 따르면, 1인당 GRDP가 높은 지역일수록 근로자의 직업 상향 이동에 긍정적인 영향을 미치는 것으로 나타났다. 한편, 지역노동시장권의 규모, 밀도, 실업률이 근로자가 보유한 교육 수준 및 직업 위치에 따라 차별적인 영향을 미치는 것으로 나타났는데, 이는 구조적 특성으로 인한 긍정적 효과가 모든 구성원에게 동등하게 배분되지는 않을 수 있는 점을 시사한다. 본 연구는 지역노동시장에서 최근 심화되고 있는 불평등 및 양극화와 관련하여 정책적 시사점을 제공한다.

• 한국수소및신에너지학회논문집
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• 제35권3호
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• pp.280-289
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• 2024

In this study, a cryogenic vessel was constructed to maintain and control the safe pressure of liquid hydrogen boil-off gas (BOG), and the numerical analysis was conducted on the development of computational fluid dynamics model inside the high-pressure vessel. An evaluation system was constructed using cryogenic inner and outer containers, pre-cooler, upper flange, and internal high-pressure container. We attempted to analyze the performance of the safety valve by injecting relatively high temperature hydrogen gas to generate BOG gas and quickly control the pressure of the high-pressure vessel up to 10 bar. As a results, the liquid volume fraction decreased with a rapid evaporation, and the pressure distribution increased monotonically inside a high pressure vessel. Additionally, it was found that the time to reach 10 bar was greatly affected by the filling rate of liquid hydrogen.

• 한국사회복지학회:학술대회논문집
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• 한국사회복지학회 2004년도 춘계학술대회 자료집
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• pp.365-382
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• 2004

The purpose of this study was to explore the concepts of health among people with mobility disabilities in order to develop a new holistic model of health and to identify implications for social work practice. A qualitative study based on face-to-face interviews with people with mobility disabilities was conducted. Nine consumers and nine social workers with mobility disabilities participated in the study. Social constructionism, heuristic paradigm, empowerment paradigm, and strength perspectives were used to form conceptual foundations to guide the study. Study participants' holistic descriptions of the concept of health encompassed five domains: biological/physical, mental/emotional, financial, relationships with others, and spiritual. Participants described health as harmony among these five domains. Harmony indicates that all five domains contribute to the concept of health, and that each domain is related to the others. Participants also viewed disability and health as an interconnected whole, not separate concept. The conceptual model developed in this study expands on the existing concepts of health by considering multiple factors at the personal and environmental levels, as well as interactions among the factors and between the levels. The personal level has five domains: biological/physical, mental/emotional, spiritual, financial, and relationships with others. The environmental level has also five domains: relationship with others, financial, social programs, social attitudes toward peoplewith disabilities, and physical environment. All factors under the personal and environmental levels also affect each other. The holistic concept of health for people with disabilities is not solely a part of the person, but rather is a function of the interaction between the person and their environment. The study demonstrated that people with disabilities have strength and resiliency, and health is an attainable goal for them, particularly when environmental and cultural barriers are addressed. The focus of social work practice should be the removal of those barriers encountered by their consumers with disabilities, as well as, the enhancement of internal factors that facilitate well-being.

• 한국지역지리학회지
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• 제17권1호
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• pp.75-95
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• 2011

이 연구는 생애주기에 따른 주거이동 모형의 횡단면적 접근과 분석이 가지는 한계의 대안으로서 출생코호트 접근을 하였다. 1970년부터 2005년까지 진주시를 사례로 5세 연령 간격으로 출생코호트를 구분하고 각각의 주거이동을 탐색하고 비교하였다. 그리고 주거수요로서 인구변천과 출산력, 주거공급으로서 주택재고와 주거지역 입지 등 변화도 함께 살펴보았다. 그 결과 모형이 강조하고 있는 연령효과 이외에도 코호트효과와 기간효과가 확인되며, 이로 인해 각 출생코호트의 주거이동 궤적에 차이가 있었다. 한편 모형이 제시하고 있는 것과는 달리 가구주의 연령이 증가하면서 연령효과가 감소하였고 이동은 감소, 안정되었다. 이에 대한 해석은 출생코호트 간의 주거승계가 미약하거나 단절되고 있고, 결과적으로 연령집단이 주거를 서로 달리하는 가족지위보다 출생코호트를 주거분화 요인 중 하나로 제시할 수 있다.

• Journal of Communications and Networks
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• 제8권4호
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• pp.451-460
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• 2006

Since low earth orbit (LEO) satellite constellations have important advantages over geosynchronous earth orbit (GEO) systems such as low propagation delay, low power requirements, and more efficient spectrum allocation due to frequency reuse between satellites and spotbeams, they are considered to be used to complement the existing terrestrial fixed and wireless networks in the evolving global mobile network. However, one of the major problems with LEO satellites is their higher speed relative to the terrestrial mobile terminals, which move at lower speeds but at more random directions. Therefore, handover management in LEO satellite networks becomes a very challenging task for supporting global mobile communication. Efficient and accurate methods are needed for LEO satellite handovers between the moving footprints. In this paper, we propose a new seamless handover management scheme for LEO satellites (SeaHO-LEO), which utilizes the handover management schemes aiming at decreasing latency, data loss, and handover blocking probability. We also present another interesting handover management model called satellite mobility pattern based handover management in LEO satellites (PatHO-LEO) which takes mobility pattern of both satellites and mobile terminals into account to minimize the handover messaging traffic. This is achieved by the newly introduced billboard manager which is used for location updates of mobile users and satellites. The billboard manager makes the proposed handover model much more flexible and easier than the current solutions, since it is a central server and supports the management of the whole system. To show the performance of the proposed algorithms, we run an extensive set of simulations both for the proposed algorithms and well known handover management methods as a baseline model. The simulation results show that the proposed algorithms are very promising for seamless handover in LEO satellites.

• 한국ITS학회 논문지
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• 제22권2호
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• pp.117-132
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• 2023

MaaS(Mobility as a service)란 기존 대중교통 수단 이외에도 다양한 교통서비스를 하나의 플랫폼에 제공하여 교통수단을 유연하게 예약 및 결제할 수 있게 하는 통합 모빌리티 서비스이다. MaaS 활성화를 위해서는 이용자들의 서비스 만족 수준이 높아야 하며, 이를 위해서는 전반적인 만족 수준에 어떠한 요인이 영향을 미치는지에 대한 연구가 필요하다. 본 연구에서는 구조방정식(SEM)을 활용하여 전반적인 만족 수준에 미치는 요인의 영향력을 파악하였으며, 중요도-만족도 분석과 의사결정나무 모형을 기반으로 이용만족도를 높일 수 있는 개선방안을 도출하였다. 분석 결과 이용자들이 사용하는 MaaS 앱의 연계 원활 수준의 개선이 필요한 것으로 분석되었다.

• 대한치과보철학회지
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• 제19권1호
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• pp.39-45
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• 1981

Distal-extension removable partial dentures have long been implicated in the increase in mobility and the destruction of the supporting structures of the primary abutment teeth. Various clasping systems have traditionally been used to retain distal extension removable partial dentures, and other designs have been proposed to minimize torquing forces on the abutment teeth. Most recent studies investigating the effects of removable partial dentures on abutment teeth have been performed in it laboratory setting. Results obtained from in vitro research have given dentists insight into removable partial denture design, but laboratory test model cannot be constructed that simulates actual functional or parafunctiona1 movements and forces. The purpose of this study was to clinically evaluate the degree of tooth mobility produced by two clasping systems (suprabulge type and infrabulge type) used for distal extension removable partial dentures. Akers clasp and R.P.I. system were selected for the evaluation, and four patients required a distal extension removable partial denture on the mandibular arch were selected for participation in the study. Two partial dentures were constructed in the same condition expect the design of clasp. All abutments in the study were mandibular first or second premolars. Measurements of mobility were made with a research tool designed by $M\"{u}hlemann$. This instrument, periodontometer, measures tooth mobility in the mouth by means of a dial gauge accurated to 0.01mm when the tooth is stressed with a force meter. Lingual and buccal deflection of abutment tooth was measured using buccal and lingual pressure. The amount of force applied was 500gm. Tooth mobility tests were made at four key stages; 1. Before insertion of the first removable partial denture, baseline mobility was establsihed. 2. After wearing of the first prosthesis, measurement was made at weekly intervals for 4 weeks. 3. The removable partial denture was then taken from the patient, and tooth mobility was measured again at weekly intervals until the patient's established baseline mobility had returned. 4. The second prosthesis of different clasp design was worn for a month and evaluated in the same manner as the first. The sequence of placement of clasping system was alternated between patients. The following results were obtained from this study; 1. The mobility of abutment tooth increased during the initial stage of wear and returned to baseline mobility after removal of removable partial dentures. 2. The mobility of abutment tooth showed no difference between Akers clasp and I-bar clasp during the 4-week test period. 3. All teeth tested showed greater mobility toward the buccal than the lingual direction.