• 한국시뮬레이션학회논문지
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• 제29권4호
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• pp.33-46
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• 2020

전자전은 상대방 전자전 무기체계나 장비에 대한 교란, 무력화, 공격 및 파괴를 목적으로 한다. 대공제압(SEAD: Suppression of Enemy Air Defense) 임무는 적의 방공망에 대한 무력화, 파괴, 혹은 일시적 기능 저하를 목적으로 하며, 전자전을 수행하는 대표적인 임무이다. 본 연구는 SEAD 임무의 효과도 분석을 위하여 DEVS(Discrete Event Systems Specification) 기반의 시뮬레이터를 개발하고 사례 분석을 통해 유용성을 입증한다. SEAD 임무는 SSJ(Self Screening Jamming), SOJ(Stand Off Jamming) 상황 하에서 적 지역으로 침투하여 HARM(High Speed Anti Radiation Missile)을 발사하는 단계까지로 한다. SAM의 대응은 SSJ, SOJ에 의해 성능의 저하가 초래되는 상태에서 임무를 수행하는 것으로 가정한다. 시뮬레이터는 전자전 장비의 제원(파라미터)과 운용전술(파리미터 혹은 알고리즘)의 조합이 임무효과도에 미치는 영향을 분석하는 것을 목적으로 하였다.

• The Journal of Asian Finance, Economics and Business
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• 제7권6호
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• pp.339-349
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• 2020

The study evaluates the performance of public hospitals in Vietnam by applying the Balanced Scorecard (BSC). The authors first review the literature to find the research gap of performance in public hospitals. Then, we built Likert questionnaires to collect data from more than 200 managers of public hospitals in the Northwestern provinces of Vietnam. The research uses correlation regression to evaluate the performance based on the influence of factors in the BSC model, including Strategic planning, Internal process, Finance, Mission, Customer, and Employee learning and growth. The results show that the performance of public hospitals in the research sample is influenced by the factors in the BSC model in descending order based on the regression coefficient as follows: Internal process, Finance, Mission, Strategic planning, Customer, Employee learning and growth. Based on the quantitative research findings, we continue by conducting some deep interviews with specialty to propose intensive recommendations about how to implement Mission, Internal process, Financial policies, etc. to managers in public hospitals with an aim to improve the performance of public hospitals in the Northwestern mountainous region of Vietnam. The lessons could be applied for other public hospitals in Vietnam and other jurisdictions that have similar conditions.

• 한국멀티미디어학회논문지
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• 제22권8호
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• pp.913-922
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• 2019

The Internet of Things (IoT) envisions smart objects collecting and sharing data at a massive scale via the Internet. One challenging issue is how to disseminate data to relevant data consuming objects efficiently. In such a massive IoT network, Mission critical data dissemination imposes constraints on the message transfer delay between objects. Due to the low power and communication range of IoT objects, data is relayed over multi-hops before arriving at the destination. In this paper, we propose a quorum-based adaptive dissemination algorithm (QADA) for the critical data in the monitoring-based applications of massive IoTs. To design QADA, we first design a new stepped-triangular grid structures (sT-grid) that support data dissemination, then construct a triangular grid overlay in the fog layer on the lower IoT layer and propose the data dissemination algorithm of the publish/subscribe model that adaptively uses triangle grid (T-grid) and sT-grid quorums depending on the mission critical in the overlay constructed to disseminate the critical data, and evaluate its performance as an analytical model.

• Journal of Astronomy and Space Sciences
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• 제38권2호
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• pp.145-155
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• 2021

In this work, preliminary launch opportunities from NARO Space Center to the Sun-Earth Lagrange point are analyzed. Among five different Sun-Earth Lagrange points, L1 and L2 points are selected as suitable candidates for, respectively, solar and astrophysics missions. With high fidelity dynamics models, the L1 and L2 point targeting problem is formulated regarding the location of NARO Space Center and relevant Target Interface Point (TIP) for each different launch date is derived including launch injection energy per unit mass (C3), Right ascension of the injection orbit Apoapsis Vector (RAV) and Declination of the injection orbit Apoapsis Vector (DAV). Potential launch periods to achieve L1 and L2 transfer trajectory are also investigated regarding coasting characteristics from NARO Space Center. The magnitude of the Lagrange Orbit Insertion (LOI) burn, as well as the Orbit Maintenance (OM) maneuver to maintain more than one year of mission orbit around the Lagrange points, is also derived as an example. Even the current work has been made under many assumptions as there are no specific mission goals currently defined yet, so results from the current work could be a good starting point to extend diversities of future Korean deep-space missions.

• Journal of Astronomy and Space Sciences
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• 제40권3호
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• pp.123-129
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• 2023

This paper presents an analysis of the trans-lunar trajectory insertion performance of the Korea Pathfinder Lunar Orbiter (KPLO), the first lunar exploration spacecraft of the Republic of Korea. The successful launch conducted on August 4, 2022 (UTC), utilized the SpaceX Falcon 9 rocket from Cape Canaveral Space Force Station. The trans-lunar trajectory insertion performance plays a crucial role in ensuring the overall mission success by directly influencing the spacecraft's onboard fuel consumption. Following separation from the launch vehicle (LV), a comprehensive analysis of the trajectory insertion performance was performed by the KPLO flight dynamics (FD) team. Both orbit parameter message (OPM) and orbit determination (OD) solutions were employed using deep space network (DSN) tracking measurements. As a result, the KPLO was accurately inserted into the ballistic lunar transfer (BLT) trajectory, satisfying all separation requirements at the target interface point (TIP), including launch injection energy per unit mass (C3), right ascension of the injection orbit apoapsis vector (RAV), and declination of the injection orbit apoapsis vector (DAV). The precise BLT trajectory insertion facilitated the smoother operation of the KPLO's remainder mission phase and enabled the utilization of reserved fuel, consequently significantly enhancing the possibilities of an extended mission.

• 한국도서관정보학회지
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• 제40권3호
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• pp.225-247
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• 2009

조직의 가치는 구성원의 신뢰를 형성하고 참여를 활성화한다. 따라서 전통적인 도서관 가치인 접근성과 지원 이외에 학교도서관의 새로운 핵심 가치를 찾는 활동이 필요하다. 본 연구에서는 국제적인 학교도서관 기준의 사명과 비전의 중심 단어를 분석하고 교육, 협동, 접근성, 문화적 소양, 민주시민 등 5개 영역의 핵심 가치를 도출하였다. 그리고 미국, 호주, 영국, 캐나다 학교도서관 기준의 사명과 비전을 분석한 결과 공통적으로 평생학습능력과 물리적 접근성 그리고 사회적 책임감을 강조하고 있는 것으로 나타났다. 특히 최근에 학교도서관 기준을 개정한 영국과 미국은 정보공학기술과 다중 정보활용능력 그리고 통합 정보활용교육과정 운영을 강조하고 있다. 궁극적으로 이러한 핵심 가치는 국내 학교도서관의 사명과 비전을 수립할 때 방향 설정과 기초 자료로 활용할 수 있을 것으로 보인다.

• 한국통신학회논문지
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• 제42권1호
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• pp.108-120
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• 2017

한국군은 현재 한국형 전술데이터링크(Link-K)를 2단계(기본형과 완성형)에 걸쳐 개발 하고 있다. 현재 Link-K 기본형에서는 모든 RICC들이 단순하게 같은 정보를 브로드캐스팅하기 때문에 불필요한 정보 공유와 비효율적인 라우팅과 같이 작전임무그룹을 지원하는데 한계가 있다. 따라서 본 논문에서는 작전임무그룹을 지원하기 위한 Zone 기반의 무선 Link-K 네트워크 구조와 라우팅 알고리즘을 제안하였다. 또한, 제안하는 라우팅 알고리즘의 효과를 증대시키기 위한 방안으로, 우선순위에 따라 메시지의 데이터를 조절하는 필터링 기법과 네트워크의 부하를 조절하는 기법을 연구하였다. 제안하는 기법의 성능을 평가하기 위하여, 작전 시나리오상황에 맞추어 기존 무선 Link-K 라우팅 알고리즘과 비교하여 작전임무그룹을 지원하는데 효과적임을 입증하였다.

• Journal of Information Processing Systems
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• 제15권6호
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• pp.1472-1488
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• 2019

Critical elements in the China's Lunar Exploration reside in that the lunar rover travels over the surrounding undetermined environment and it conducts scientific exploration under the ground control via teleoperation system. Such an interplanetary transportation mission teleoperation system belongs to the ground application system in deep space mission, which performs terrain reconstruction, visual positioning, path planning, and rover motion control by receiving telemetry data. It plays a vital role in the whole lunar exploration operation and its so-called trustworthy evidence must be assessed before and during its implementation. Taking ISO standards and China's national military standards as trustworthy evidence source, the net assessment model and net assessment method of teleoperation system are established in this paper. The multi-dimensional net assessment model covering the life cycle of software is defined by extracting the trustworthy evidences from trustworthy evidence source. The qualitative decisions are converted to quantitative weights through the net assessment method (NAM) combined with fuzzy analytic hierarchy process (FAHP) and entropy weight method (EWM) to determine the weight of the evidence elements in the net assessment model. The paper employs the teleoperation system for interplanetary transportation as a case study. The experimental result drawn shows the validity and rationality of net assessment model and method. In the final part of this paper, the untrustworthy elements of the teleoperation system are discovered and an improvement scheme is established upon the "net result". The work completed in this paper has been applied in the development of the teleoperation system of China's Chang'e-3 (CE-3) "Jade Rabbit-1" and Chang'e-4 (CE-4) "Jade Rabbit-2" rover successfully. Besides, it will be implemented in China's Chang'e-5 (CE-5) mission in 2019. What's more, it will be promoted in the Mars exploration mission in 2020. Therefore it is valuable to the development process improvement of aerospace information system.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.283-292
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• 2008

The foremost criterion in the design of a Satellite Launch Vehicle(SLV) is its performance capability to boost the designated payload to the desired mission orbit; it starts from focusing on the SLV configuration to achieve the velocity requirements($}\Delta}V$) for the mission. In this paper we review an analytical approach which is suitable enough for preliminary conceptual design and is used previously to optimize stage configurations for Two Stage to Orbit SLV for Low Earth Orbit(LEO) Missions; we have extended this approach to Three Stage to Orbit SLV and compared different propellant options for the mission. The objective is to minimize the Gross Lift off Weight(GLOW). The primary performance figures of merit were the total inert weight of the SLV and the payload weight that the SLV could lift into LEO, given candidate propulsion systems. The optimization is achieved by configuring the $}\Delta}V$ between stages. A comparison of configurations of single-stage and multi-stage SLVs is made for different propellants. Based upon the optimized stage configurations a comparative performance analysis is made between Liquid and Solid fueled SLV. A 3 degree of freedom trajectory-analysis program is modeled in SIMULINK and used to conduct the performance analysis. Furthermore, a cost analysis is performed on our stage optimized SLVs. The cost estimation relationships(CER) used give us a comparison of development and fabrication costs for the Liquid vs. Solid fueled SLV in man years. The pros and cons of the production, operation ability, performance, responsiveness, logistics, price, shelf life, storage etc of both Solid and Liquid fueled SLVs are discussed. The statistics and data are used from existing or historical(real) SLV stages.

• 한국산학기술학회논문지
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• 제15권10호
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• pp.6056-6065
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• 2014

본 연구는 한국 도시거주자의 목적 지향성향 척도 개발에 관한 연구이다. 목적지향성향의 개념을 정립하기 위하여 종교적 학문적 연구를 참조하고 기존의 생산성이나 성공적 노화 또는 삶의 질 척도를 검토하였다. 그 결과 설문을 위해 57개의 문항을 작성하였으며 목회자, 신학대학교수, 사회복지사 등의 축조심의를 거쳐 44개 문항으로 예비문항을 만들었다. 이후 응답자로부터의 효과적 설문을 위해 통계전문 교수와 중복조항 제거, 체계적인 연구 모델 수립을 위해 당해 전문 교수의 검토를 통해 문항을 수정하여 최종 27개 문항을 확정하였다. 수도권을 중심으로 설문을 실시하여 380부를 수집한 후 요인분석을 한 결과 측정도구의 타당성을 검증하였으며, "존재의 인지", "자율적 삶", "자기완성", "적극성", "수용성", "경제성" 등 6개의 하위 요인으로 분류되었다. 신뢰도의 경우 Cronbach's ${\alpha}$값이 0.6 이상으로 신뢰할만한 수준이었다.