• Title/Summary/Keyword: 1st-order system

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HLA/RTI based on the Simulation Composition Technology (HLA/RTI 기반의 시뮬레이션 조합 기술)

  • Kim, Jingyu
    • Journal of the Korea Institute of Military Science and Technology
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    • v.19 no.2
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    • pp.244-251
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    • 2016
  • In defense domain, mission level and engagement level simulation tools exist. In order to experiment a simulation scenario for obtaining results of both mission level and engagement level simulations, we should write a same simulation scenario in a mission level simulation tool as well as an engagement level simulation tool, and we have to operate these tools for analysis of each purpose. Moreover, we could not guarantee that these scenarios are completely same since each scenario is composed of different fidelities of simulation models, although the scenarios are written by a same experimenter and with same simulation purpose. To deal with the difficulties, I propose an approach to analysis of both mission level and engagement level simulations from one simulation result. For this, I have built Composite Combat Mission Planning Simulation Environment (CCMPSE). In this paper, the HLA/RTI based simulation composition technology and my experiences for the designed Composite Combat Mission Planning Simulation Control System (CCMPSCS) are explained. Moreover, This paper also conducts a case study with EADSIM, SADM, and the CCMPSCS. Finally, this paper provides lesson learned from the case study.

Equivalent Circuit Modelling of FFR Transducer Array for Sonar System Design (소나 시스템 설계를 위한 FFR 트랜스듀서 어레이의 등가회로 모델링)

  • Kim, In-Dong;Choi, Seung-Soo;Lee, Haksue;Lee, Seung Woo;Moon, Wonkyu
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.4
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    • pp.629-635
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    • 2017
  • Free-Flooded Ring (FFR) transducer array for use in Sonar system can be driven with large amplitude in a wide frequency band due to its structural characteristics, in which two resonances of a ring mode (1st radial mode) and an inner cavity vibration mode occur in a low frequency band. Since its sound wave generation characteristics are not influenced by the water pressure, the FFR transducer array is widely used in the deep sea. So FFR has been recognized as a low-frequency active sound source and has received much attention ever since. In order to utilize the FFR transducer array for SONAR systems in military and industrial applications, its equivalent electric circuit model is necessary especially to design the matching circuit between the driving power amplifier and the FFR transducer array. Thus this paper proposes the equivalent electric circuit model of FFR transducer array by using measured values of parameter, and suggest the improved method of parameter identification. Finally it verifies the effectiveness of the proposed circuit model of FFR transducer array by experimental measurements.

Numerical Analysis of Cold Storage System with Array of Solid-Liquid Phase Change Module (저온의 고-액상변화 모듈 용기의 배열에 따른 축냉시스템의 수치해석)

  • Mun, Soo-Beom
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.21 no.5
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    • pp.577-582
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    • 2015
  • This paper is the fundamental study for the application of cold storage system to the transportation equipment by sea and land. This numerical study presents the solid-liquid phase change phenomenon of calcium chloride solution of 30wt %. The governing equations are 1-dimensional unsteady state heat transfer equations of $1^{st}$ order partial differential equations. This type of latent heat storage material is often usable in fishery vessel for controlling the temperature of container with constant condition. The governing equation was discretized with finite difference method and the program was composed with Mathcad program. The main parameters of this solution were the initial temperature of heat storage material, ambient temperature of cold air and the velocity of cold air. The data of boundary layer thickness becomes thin with the increasing of cold air flowing velocity and also the heat storage completion time become shorten.

Numerical study on the effects of air staging on combustion in the three air stage heavy oil fired combustion system (삼단중유연소 버너에서 다단비가 연소현상에 미치는 영향에 대한 수치 연구)

  • Lee, Sung-Soo;Kim, Hyuck-Ju;Park, Byoung-Sik;Kim, Jong-Jin;Choi, Gyu-Sung
    • 한국연소학회:학술대회논문집
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    • 2004.06a
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    • pp.235-241
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    • 2004
  • Computations were performed to investigate the effects of air staging on combustion in three stage heavy-oil fired combustion burner. The burner was designed for 3 MW. Different amounts of air are introduced into each 3 three stages by means of each dampers. The goal of the study is to understand combustion phenomena according to each air stage mass ratios through CFD. Air flow rates at three inlets are adjusted by dampers inside a burner. Here, injection conditions of liquid fuel are kept constant throughout all simulations. This assumption is made in order to limit the complexity of oil combustion though it may cause some disagreement. In case of cold flows, only longitudinal velocities arc considered, On the other hand, flow, temperature and NOx generations are taken into account for reactive flows. Simple parametric study was conducted by setting 1'st air stage mass ratio as a parameter. And an optimal operation condition was found. The computational study is based on k-e model, P-1 radiation model(WSGGM) and PDF, and is implemented on a commercial code, FLUENT.

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Hierarchical Lazy Greedy Algorithm for Weapon Target Assignment (무기할당을 위한 계층적 레이지 그리디 알고리즘)

  • Jeong, Hyesun
    • Journal of the Korea Institute of Military Science and Technology
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    • v.23 no.4
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    • pp.381-388
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    • 2020
  • Weapon target assignment problem is an essential technology for automating the operator's rapid decision-making support in a battlefield situation. Weapon target assignment problem is a kind of the optimization problem that can build up an objective function by maximizing the number of threat target destructed or maximizing the survival rate of the protected assets. Weapon target assignment problem is known as the NP-Complete, and various studies have been conducted on it. Among them, a greedy heuristic algorithm which guarantees (1-1/e) approximation has been considered a very practical method in order to enhance the applicability of the real weapon system. In this paper, we formulated the weapon target assignment problem for supporting decision-making at the level of artillery. The lazy strategy based on hierarchical structure is proposed to accelerate the greedy algorithm. By experimental results, we show that our algorithm is more efficient in processing time and support the same level of the objective function value with the basic greedy algorithm.

A Study on the Reset of Examination Criteria for Energy Use Plan through Consultation Case Analysis (협의 사례 분석을 통한 에너지사용계획 검토기준 재설정 연구)

  • Suh, Kwang-Soo
    • Journal of the Korean Solar Energy Society
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    • v.33 no.4
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    • pp.59-69
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    • 2013
  • The Consultation about Energy Use Plan is prescribed by the Energy Use Rationalization Act. In order to reset Examination Criteria for Energy Use Plan, consultation case analysis from 2001 to 2010 were carried out and National Energy Master Plan was reviewed. This study proposes that Examination Criteria for Energy Use Plan be should divided into Urban & Tourism complex development project and Industrial complex development project for the prevention of civil complain. Also predicts that effect of energy savings calculated by Reset Examination Criteria on $1^{ST}$ energy demand BAU at 2030 is 2.2%, effect of new & renewable energy utilization at 2030 is 3% and the rate of $CO_2$ reduction to greenhouse gas emission BAU at 2020 is 1.1%.

Planning Directions of Community Facilities Integrating Generations based on Local Communities

  • Jae Hee CHUNG;Ji Min KIM;Su Jin LEE;Sung Ze YI
    • The Journal of Economics, Marketing and Management
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    • v.12 no.1
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    • pp.39-51
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    • 2024
  • Purpose: This study aims to derive planning directions of community facilities integrating generations based on local communities to promote sustainable intergenerational exchange by analyzing the spatial configuration and programs of domestic and foreign generation-integrated community facilities based on local communities. Research design, data and methodology: Through theoretical consideration, the concept of intergenerational integration, types of intergenerational exchange, and spatial arrangement types were identified. Then, case study analysis of domestic and foreign community facilities with well-planned intergenerational exchange spaces and programs were conducted to identify intergenerational integration, and to derive community facility planning direction. Results: The results of this research are as follows. First, in terms of humanware, in order to revitalize continuous exchange between the 1st, 2nd, and 3rd generations, a systematic support system is needed to build mutual trust through voluntary participation by each generation. Second, it is important to provide a variety of shared spaces while maintaining the uniqueness of each facility from a hardware perspective, and must be planned in such a way that selective interaction takes place with privacy and interaction in mind. Third, in terms of software, programs that meet the characteristics of each user must be provided. Conclusions: It is expected that the results of this research can be used as basic data for planning community facilities that integrate generations based on local communities, contributing to the search for sustainable ways to revitalize intergenerational exchange in the future.

Study on Volterra System for Variation of Metacentric Height in Waves and its Application to Analysis of Parametric Roll (볼테라 시스템을 이용한 파랑 중 파라메트릭 횡동요에 대한 연구)

  • Lee, Jae-Hoon;Kim, Yonghwan
    • Journal of the Society of Naval Architects of Korea
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    • v.54 no.3
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    • pp.227-241
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    • 2017
  • In this study, a Volterra system for the variations of metacentric height (GM) in waves is employed to simulate the parametric roll phenomena of ships in head sea condition. Using the present Volterra system, the transfer function of each harmonic component in the GM variation is computed for different ship models, including mathematical models and a real containership, and the results are validated through the comparison with the values obtained using the direct calculations based on a weakly nonlinear time-domain method. Then, a semi-analytic approach employing a 1-degree of freedom equation for roll motion is developed to simulate the parametric roll motions in irregular waves. In the derived approach, the nonlinear and time-varying restoring forces in the waves are approximated using the Volterra system. Through simulations of the parametric roll for different sea states, the effects of the 1st and 2nd-order harmonic components of the variations in the occurrence and amplitude of the parametric roll motions are investigated. Because of the strong nonlinearities in the phenomena, a stochastic analysis is conducted to examine the statistical properties of the roll motions in consideration of the sensitivities and uncertainties in the computations.

A Study on the Chinese Arbitration Act (중국 중재법에 관한 연구)

  • Yoon, Jin Ki
    • Journal of Arbitration Studies
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    • v.9 no.1
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    • pp.183-232
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    • 1999
  • The legislative body of The People's Republic of China, the National People's Congress, enacted the first arbitration act in China's history on August 31st, 1994, which took effect on September 1, 1995. The problems revealed through a comparison of China's Arbitration Act with the UNCITRAL model arbitration law were studied as well as the enacting process, background, status and system, important contents, problems of Chaina's Arbitration Act, and the differences between the old arbitration regulations and the new arbitration act. These are all discussed in this paper. The Arbitration Act is the basic act ruling over china's arbitration system: it unified the previously confusing laws and regulations relevant to the arbitration system, and the act brings out fundamental changes in China's domestic arbitration to the level of international arbitration standards. It is possible to view this act as a cornerstone in China's arbitration system. But, as discussed in this paper, there are still a lot of problems with the new act and only a few of the merits which the UNCITRAL model arbitration law has. First, under China's Arbitration Act, parties enjoy autonomy to some degree, but the range of party autonomy, compared to that of the UNCITRAL model arbitration law, is too narrow. Second, because China's Arbitration Act didn't explicitly provide issues which can give rise to debate, a degree of confusion in its interpretation still remains. Third, China's Arbitration Act's treatment of some important principles was careless. Fourth, in some sections, China's Arbitration Act is less reasonable than the UNCITRAL model arbitration law. These problems must be resolved in order to develop China's arbitration system. The best way of resolving these problems for China is to adopt the UNCITRAL model arbitration law. But it is difficult to expect that China will accept this approach, because of the present arbitration circumstances in China. Although it is difficult to accept all the contents of the UNCITRAL model arbitration law, China's legislators and practitioners must consider the problems mentioned in this paper.

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Specificity of Majangcheon (Chuncheon) Based on Fish Community (어류군집에 따른 마장천(춘천)의 특이성)

  • Lee, Hankyu;Lee, Kwangyeol;Jang, Changwon;Lee, Jaeyong;Cheon, Jaeryong;Choi, Jaeseok
    • Journal of Environmental Impact Assessment
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    • v.28 no.2
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    • pp.129-140
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    • 2019
  • Majangcheon is a small agricultural stream which is located in Chuncheon-si, Gangwon-do. To understand ecological characteristics of Majangcheon as biological habitats, we surveyed its physical environment and fishes from June 2016 to September 2016. The altitudinal difference between lowest and highest point of the stream was 3 meters and the first-order stream under a map drawn on a scale of 1:25,000. The flow rate of stream was slow in overall with $0.09-0.48m{\cdot}s^{-1}$. More than 50% of clay were found in all points except for the point St. 3 in the riverbed structure surveyed. A total of 2,532 individuals of 22 species in nine families were collected from Majangcheon. Of them, stillwater-living species (Acheilognathinae and Carassius auratus) and floating species (Zacco platypus and Oryzias sinensis) were mainly collected. In Majangcheon, thus, both of stillwater-living and floating fishes were specifically coexisted. The correspondence analysis, based on fishes collected from Majangcheon and past research, showed that Majangcheon is closer to the flat streams in Gyeonggi-do rather than the mountainous streams in Gangwon-do but it appeared as an independent group from those of two regions. As a result, Majangcheon is a stream with specificity of fish community.