• Journal of the Korea Society for Simulation
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• v.9 no.3
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• pp.65-75
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• 2000

In recent years, significant advances in computers and communication technologies have made multimedia services feasible. As a result, various queuing models and cost models on architecture and data placement for multimedia server have been proposed. However, these analytical techniques use only probabilistic models to represent the behavior of a system, and then they have several limitations like accuracy. Simulation is a viable alternative to analytical model. It avoids many of the limitations associated with analytical techniques, allowing for more precise representation of system attributes like workload in program code. In this paper, we propose a simulation test bed that can evaluate performance of real-time multimedia server by using simulation model.

• Asia pacific journal of information systems
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• v.14 no.4
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• pp.49-70
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• 2004

Multi-agent technology is being regarded as one of the promising technologies for today's supply chain management because of its desirable features such as autonomy, intelligence, and collaboration. This paper suggests a multi-agent system architecture with which companies can improve the efficiency of their supply chains by collaborative operation. Reflecting the practical difficulties of collaboration in complex supply chains, the architecture allows agent systems to share information with only neighboring companies for the coordinated operation. The suggested architecture is elaborated with a collaboration model based on Petri-net, conversation models for communication, and internal behavior models of each agent. A simulation experiment was performed for the evaluation of the suggested architecture. The result implies that when the estimation of market demand is higher than a certain level, the suggested architecture can be beneficial.

• ETRI Journal
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• v.24 no.2
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• pp.161-171
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• 2002

This paper proposes a novel decision feedback differential phase detection (DF-DPD) for M-ary DPSK. A conventional differential phase detection method for M-ary Differential Phase Shift Keying (DPSK) can simplify the receiver architecture. However, it possesses a poorer bit error rate (BER) performance than coherent detection because of the prior noisy phase sample. Multiple-symbol differential detection methods, such as maximum likelihood differential phase detection, Viterbi-DPD, and DF-DPD using L-1 previous detected symbols, have attempted to improve BER performance. As the detection length, L, increases, the BER performance of the DF-DPD improves but the complexity of the architecture increases dramatically. This paper proposes a simplified DF-DPD architecture replacing the conventional delay and additional architecture with an accumulator. The proposed architecture also improves BER performance by minimizing the current differential phase noise through the accumulation of previous differential phase noise samples. The simulation results show that the BER performance of the proposed architecture approaches that of a coherent detection with differential decoding.

• Journal of the Korea Society for Simulation
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• v.22 no.2
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• pp.73-83
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• 2013

This paper presents design and implementation of the monitoring system for the distributed simulation of underwater warfare. As importance of defense modeling and simulation(M&S) has raised, Simulation-Based Acquisition(SBA) was authorized for an obligatory process in the development process of weapon systems. Yet, it requires tremendous resources to develop a large-scale simulation system that describes complex and broad battlefields. Therefore, an approach of the distributed system was devised to develop a new simulation system combining legacy simulators that were developed for confined purpose and sole operations. High-Level Architecture(HLA) of distributed systems is a standardized protocol by IEEE for the distributed simulation system and Run-Time Infrastructure(RTI) is an implementation of HLA to structure efficient distributed systems. The main objective of this paper is to derive appropriate monitoring factors for underwater warfare simulation, design and implementation of the monitoring system to analyze the factors based on HLA/RTI.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.6
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• pp.23-28
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• 2002

• Journal of Korean Society of Rural Planning
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• v.20 no.2
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• pp.103-114
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• 2014

The objective of this study was to develop agricultural reservoir water supply simulation system to assess water cycle of agricultural water district. Developed system was named as ARWS (Agricultural Reservoir Water supply simulation System). ARWS consists of platform and independent modules. In ARWS, reservoir inflow was calculated using Tank model, and agricultural water supply was calculated considering current farming period and mid-summer drainage. ARWS was applied to simulate water level of Gopung and Tapjung reservoir in 2011 - 2012. The results were compared to simulation results of HOMWRS and observed data. Average $R^2$, EI, RMSE of ARWS were 0.76, 0.46, 1.78 (m), average $R^2$, EI, RMSE of HOMRWS were 0.88, -0.14, 2.37 (m) respectively. Considering statistical variances, water level simulation results of ARWS were more similar to observed data than HOMWRS. ARWS can be useful to estimate reservoir water supply and assess hydrological processes of agricultural water district.

• Journal of the Korea Society for Simulation
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• v.22 no.2
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• pp.1-10
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• 2013

Modeling and simulation techniques construct experimental environment considering battlefields and are able to analyze performance of components of weapon system that closely resemble reality. However, developed model has low scalability and not cared reusability because it has been used only in a limited range of domain. In this paper, we develop a verification tool to verify reusability of developed component for dynamic reconfiguration and to judge scalability of it and a management tool to control data of it effectively. In addition, dynamic reconfiguration architecture of guided weapon systems designed in the previous study has been applied to SAM(Surface to Air Missile) System Simulator, and we study effectiveness of the developed component. Thus the user can configure various guided weapon systems through simulation application of dynamic reconfiguration architecture of component.

• Journal of the Korea Society for Simulation
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• v.27 no.1
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• pp.15-24
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• 2018

High Level Architecture(HLA) for modeling and simulation is an international technical standard to achieve simulation interoperability and reusability. Building federation through the interworking of federates is being used in various fields and is being used in KR(Key Resolve), UFG(Ulchi-Freedom Guardian) as a representative in domestic military. Currently, United States Department of Defense emphasizes the HLA compliance test, which confirms the compliance of Federate by using HLA. However, due to the limitations of testing tools, an HLA compliance test of DoD is not able to perform some of the functional tests on HLA/RTI services such as federation storage/recovery services and also exclude inspection of exchange data between federates. To solve these problems, this paper proposes an HLA compliance testing system of ROK suitable for domestic situations. This will enable effective HLA compliance testing and improve interoperability between federates.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.2
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• pp.122-129
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• 2013

This paper shows the method for simulating the two-way communication network to transmit information in Smart Grid, which is currently investigated by many researchers. The simulation method can be basically applied to analysis of data traffic for various electric devices such as smart meters, which were tested in Jeju island and massively deployed with nationwide scale.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.4
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• pp.207-212
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• 2015

The use of groundwater and ground_heat is one of the ways to use natural and renewable energy, and it has been considered as a technology to reduce greenhouse gas emissions and increase energy-saving. There are a few researches on the optimum design for the open-loop geothermal system. In this study, to develop the optimal design method numerical simulation of the open-loop geothermal system with two-wells was performed by a groundwater and heat transfer model. In this paper, a study was performed to analyze the system performance according to well distance and pumping flow rate. In the result, average heat exchange rate and heat source temperature were calculated and it was found that they were dependent on the pumping rate.