• 한국시뮬레이션학회:학술대회논문집
• /
• 한국시뮬레이션학회 1997년도 춘계 학술대회 발표집
• /
• pp.9-9
• /
• 1997

• 대한전기학회논문지:전력기술부문A
• /
• 제52권6호
• /
• pp.295-300
• /
• 2003

Voltage instability has been studied for some decade now. But, There is not generally accepted definition of voltage instability because of the complex phenomenon and the variety of ways in which it can manifest itself. Both IEEE and CIGRE have the respective definitions. The areas of voltage instability research are the analysis, simulation and countermeasure of voltage instability. It needs to model the components of the power system to simulate the voltage instability and voltage collapse. At the beginning, the static simulation was used. This method provides the voltage stability indices and it requires less CPU resource and gives much insight into the voltage and power problem. However, it is less accurate than the dynamic simulation peformed in the time domain simulation. So, when it appears difficult to secure the voltage stability margin in a static stability, it is necessary to perform the dynamic simulation. To perform time-domain simulation, we have to model the dynamic component of the power system like a generator and a load. The dynamic simulation provides the accurate result of the voltage instability. But, it is not able to provide the sensitivity information or the degree of stability and it is time consuming and it needs much CPU resource. In this Paper, we perform a dynamic simulation of voltage instability and voltage collapse using EMTP MODELS. The exponential load model is designed with MODEIS and this load model is connected with test power system. The result shows the process of voltage change in time domain when the voltage instability or voltage collapse occurs.

• 한국시뮬레이션학회논문지
• /
• 제21권4호
• /
• pp.81-90
• /
• 2012

본 논문은 지상무기체계 교전을 모의하기 위한 시뮬레이션 시스템 구축에 관한 연구이다. 본 논문에서는 에이전트 시뮬레이션 설계 방법론에 기반하여 시뮬레이션 시스템 아키텍처를 제안한다. 제안된 아키텍처의 각 개체는 에이전트 기반으로 모듈화된 컴포넌트들을 조합하여 구성된다. 이와 같은 개체 구성 방법은 개체의 재사용성과 조합성을 향상시키고, 결과적으로 시뮬레이션 시스템의 개발에 투입되는 시간, 비용, 및 노력을 감소시킨다. 지상무기체계 교전의 모의는 환경의 영향을 반영하는 것이 매우 중요하다. 제안된 아키텍처의 합성전장환경은 전장의 환경 데이터를 가지며 시뮬레이션 시스템의 전투개체와 계속적으로 상호작용한다. 이러한 아키텍처를 기반으로 구축된 시뮬레이션 시스템은 목적에 따라 다양한 지상무기체계 교전 시나리오의 신속한 모의가 가능하고, 개체들의 행위 수행에 환경 영향이 반영되어 신뢰성 있는 시뮬레이션 결과를 도출할 수 있다. 본 논문은 제안된 아키텍처를 기반으로 예제 시스템을 구축하여 그 효용성을 증명하였다.

• 한국건설관리학회논문집
• /
• 제7권1호
• /
• pp.73-79
• /
• 2006

그래픽 시뮬레이션은 건설공사의 시공계획을 위해서 매우 유용하게 쓰일 수 있으나, 토공과 같이 비정형의 물체를 다루는 경우에는 그래픽 시뮬레이션의 적용에 한계를 갖게 된다. 이러한 경우에는 사용 장비의 작업시간, 대기시간, 작업용량 등의 수치적 데이터에 근거하여 공정 전체의 생산성에 대한 분석을 수행하게 되는 수학/통계적 시뮬레이션이 그 장점을 보이지만, 프로세스 모델 구축의 어려움, 수치적 시뮬레이션 결과의 신뢰성 확보 문제 등으로 건설 분야에서의 활용이 매우 제한되어 있는 실정이다. 본 연구에서는 비정형 물체를 다루는 공사인 토공작업에 대한 시각화를 건설공사에 주로 사용되는 수학/통계적 시뮬레이션인 불연속사건 시뮬레이션(Discrete Event Simulation) 프로그램들의 출력을 분석하여 작업시간, 대기시간, 운반물량 등에 대한 수치적 결과를 건설작업의 그래픽 시각화로 표현하였다. 이를 통하여 건설공사의 시공계획 시에 시뮬레이션을 활용하면 사전에 시공과정을 수행하여 봄으로써 최적의 건설장비 및 공법을 선택하여 효율적으로 운용하게 함이 가능함을 입증하고자 하였다.

• Asia Marketing Journal
• /
• 제14권4호
• /
• pp.77-94
• /
• 2013

Really new products (RNPs) provide novel benefits yet many consumers are reluctant to accept these highly innovative new products. Previous literature has shown that mental simulation is an effective method for enhancing the evaluation of RNPs. However, Castano et al. (2008) and Zhao, Hoeffler, and Zauberman (2011) demonstrate conflicting results as to which type of mental simulation (i.e., process versus outcome) is more effective for the enhancement of RNP evaluation. The authors try to reconcile these results by incorporating a moderating variable which is personal need for structure (PNS). PNS is an individual difference variable that taps the differences in people's propensity to cognitively structure and simplify their environment (Neuberg and Newsom 1993). From the analysis of the previous two works, the authors point out that consumers' susceptibility to uncertainty may contribute to the different results, and suggest that this susceptibility is dependent on consumers' PNS. To test the hypotheses established, an experiment was conducted. Waterless washing machine was presented as a RNP and PNS was measured by using the 12-item PNS Scale (Thompson et al. 2001). The results of the study show that for high-PNS consumers, process simulation is more effective than outcome simulation for enhancing the evaluation of a RNP, whereas for low-PNS consumers, outcome simulation is more effective than process simulation. This research contributes to the mental simulation and new product literature by suggesting and verifying that PNS moderates the effects of process versus outcome simulations for enhancing the evaluation of RNPs. This research provides important managerial implications for marketing managers of RNPs, indicating that they should take account of the target consumers' PNS in planning marketing communications. Specifically, when targeting high-PNS consumers, marketing communications that encourage process simulation may be more effective than those that encourage outcome simulation. In contrast, when targeting low-PNS consumers, marketing communications that encourage outcome simulation may be more effective than those that encourage process simulation.

• Wind and Structures
• /
• 제39권2호
• /
• pp.125-140
• /
• 2024

The simulation of non-stationary wind velocity is particularly crucial for the wind resistant design of slender structures. Recently, some data-driven simulation methods have received much attention due to their straightforwardness. However, as the number of simulation points increases, it will face efficiency issues. Under such a background, in this paper, a time-varying coherence matrix decomposition method based on Diagonal Proper Orthogonal Decomposition (DPOD) interpolation is proposed for the data-driven simulation of non-stationary wind velocity based on S-transform (ST). Its core idea is to use coherence matrix decomposition instead of the decomposition of the measured time-frequency power spectrum matrix based on ST. The decomposition result of the time-varying coherence matrix is relatively smooth, so DPOD interpolation can be introduced to accelerate its decomposition, and the DPOD interpolation technology is extended to the simulation based on measured wind velocity. The numerical experiment has shown that the reconstruction results of coherence matrix interpolation are consistent with the target values, and the interpolation calculation efficiency is higher than that of the coherence matrix time-frequency interpolation method and the coherence matrix POD interpolation method. Compared to existing data-driven simulation methods, it addresses the efficiency issue in simulations where the number of Cholesky decompositions increases with the increase of simulation points, significantly enhancing the efficiency of simulating multivariate non-stationary wind velocities. Meanwhile, the simulation data preserved the time-frequency characteristics of the measured wind velocity well.

• 한국시뮬레이션학회논문지
• /
• 제16권2호
• /
• pp.65-74
• /
• 2007

가상생산기술은 신제품의 개발, 새로운 장비 개발 및 새로운 제조시스템 개발에 유용한 도구이며, 특히 3D 시뮬레이션 기술은 가상생산의 핵심기술이다. 3D 시뮬레이션 기술은 기계적 시뮬레이션 기술과 이산사건 시뮬레이션 기술로 구분할 수 있다. 본 논문에서는 휴대폰 카메라에 장착되는 렌즈모듈 조립을 생산하는 국내 회사의 사례를 소개한다. 이 회사에서는 렌즈모듈 조립공정을 현재 수작업으로 하고 있는데 자동화시스템을 개발하기로 결정하였으며 이를 위해 3D 시뮬레이션 기술을 도입하기로 하였다. 3D 시뮬레이션 기술은 시스템 개념설계단계에서부터 적용이 되었는데, 단위 장비 개발을 위해서는 $CATIA^{(R)}$와 $IGRIP^{(R)}$이 활용되었으며, 시스템 설계를 위해서는 이산사건 시뮬레이션 도구인 $QUEST^{(R)}$가 활용되었다. 논문의 목적은 새로운 자동화 설비의 기술적. 경제적 타당성을 검증하는 것이다. 개발결과 takt time 이 기존의 수작업에 비해 4분의 1 수준으로 감소되었으며, 이에 따른 작업자 인원도 대폭 감소되었다.

• 한국시뮬레이션학회:학술대회논문집
• /
• 한국시뮬레이션학회 1992년도 제2회 정기총회 및 추계학술 발표회 발표논문 초록
• /
• pp.1-1
• /
• 1992

This paper presents a user-oriented port expansion simulation model that determines the future economic port capacity to meet the projected demand. The model consists of two parts; a physical impact simulation, and an economic impact simulation. The first part of the model simulates the effects caused by the port capacity expansion. The second part evaluates the port economics due to changes in the port capacity. The model was validated by applying it to the actual port expansion followed at the Port of Mobile, Alabama. A case study is then presented to demonstrate the capacity of the model with a coal handling port, the McDuffie Terminals at the Port of Mobile.

• Tribology and Lubricants
• /
• 제32권1호
• /
• pp.9-17
• /
• 2016

Contact between solid surfaces is one of the most important factors that influence dynamic behavior in micro/nanoscale. Although numerous theories and experimental results on contact behavior have been proposed, a thorough investigation for nanomaterials is still not available owing to technical difficulties. Therefore, molecular dynamics simulation was performed to investigate the contact behavior of nanomaterials, and the application of conventional contact theories to nanoscale was assessed in this work. Particularly, the contact characteristics of cylindrical nanowires were examined via simulation and contact theories. For theoretical analysis, various contact models were utilized and work of adhesion, Hamaker constant and elastic modulus those are required for calculation of the models were obtained from both indentation simulation and tensile simulation. The contact area of the cylindrical nanowire was assessed directly through molecular dynamics simulation and compared with the results obtained from the theories. Determination of the contact area of the nanowires was carried out via simulation by counting each atom, which is within the equilibrium length. The results of the simulation and theoretical calculations were compared, and it was estimated that the discrepancy in the results calculated between the simulation and the theories was less than 10 except in the case of the smallest nanowires. As the result, it was revealed that contact models can be effectively utilized to assess the contact area of nanomaterials.

• 한국측량학회지
• /
• 제30권6_2호
• /
• pp.631-642
• /
• 2012

This study aims to predict inundation and flood-stricken areas more accurately by simulating flood damage caused by reversible flow of rain water in the upper water system through precise 3D terrain model and backwater output. For the upstream of the South Han-River, precise 3D terrain model was established by using aerial LiDAR data and backwater by area was output by applying the storm events of 2002 including the history of flood damage. The 3D flood simulation was also performed by using GIS Tool and for occurrence of related rainfall events, inundation events of the upriver region of water system was analyzed. In addition, the results of flood simulation using backwater were verified by making the inundation damage map for the relevant area and comparing it with flood simulation's results. When comparing with the results of the flood simulation applying uniformly the gauging station's water surface elevation used for the existing flood simulation, it is found that the results of the flood simulation using backwater are close to the actual inundation damage status. Accordingly, the causes of flood occurred in downstream of water system and upstream that has different topographic characteristics could be investigated and applying the simulation with backwater is proved more proper in order to procure accuracy of the flood simulation for the upriver region.