• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.3
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• pp.410-425
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• 1997

Buildings are mostly under part load conditions causing an inefficient system operation in terms of energy consumption. It is critical to operate building air-conditioning system with a scientific or optimal manner which minimizes energy consumption and maintains thermal comfort by matching building sensible and latent loads. Little research has been performed in developing general methodologies for the optimal operation of air-conditioning system. Based on this research motivation, system simulation program was developed by adopting various equipment operating strategies which are energy efficient especially for humidity control in summer. A numerical optimization technique was utilized to search optimal solution for multi-independent variables and then linked to the developed system simulation model within a mam program. The main goal of the study is to provide a systematic framework and guideline for the optimal operation of air-conditioning system focusing on air-side. For given cooling loads and ambient outdoor conditions the optimal operating strategies of a commercial building are determined by minimizing a constrained objective function by a nonlinear programming technique. Desired space setpoint conditions were found through evaluating the trade-offs between comfort and system power consumption. The results show that supply airflow rate and compressor fraction play main roles in the optimization process. It was found that variable setpoint optimization technique could produce lower indoor humidity level demanding less power consumption which will be benefits for building applications of humidity problem.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.5
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• pp.691-700
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• 2006

This study conducted to optimize the design and operation of orifice typed distribution channels which were generally constructed to link the rapid mixing process and flocculation/sedimentation basin. To accomplish the goal of this study, programming step method using FORTRAN 90, was applied it to simulate the performance of existing distribution channel in the selected S DWTP (Drinking Water Treatment Plant). The proposed step method program was validated in terms of the feasibility with comparison between the measurement and prediction value in each orifice. From the evaluation results of the current conditions with the design and operation, it was revealed that the existing gradient of the tapered channel is not appropriate. Also, we suggested that in the case of the inlet width being 3.5m, reducing the downstream width by about 0.5m would make more equitable distribution flow in the channel. Consequently, dealing with various conditions of the design and operation with distribution channel, we could conclude that for the parallel typed channel, as the width is wider and the diameter of orifice is smaller, the more equitable distribution occur. In addition, the inlet flowrate and the number of orifice can affect the flow velocity in the channel.

• Journal of Computing Science and Engineering
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• v.2 no.4
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• pp.357-374
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• 2008

Over the past few decades, a considerable number of studies have been conducted on the technologies to build an UAV (Unmanned Aerial Vehicle) control system. Today, focus in research has moved from a standalone control system towards a network-centric control system for multiple UAV systems. Enabling the design of such complex systems in easily understandable forms that are amenable to rigorous analysis is a highly desirable goal. In this paper, we discuss our experimental evaluation of the Time-triggered Message-triggered Object (TMO) structuring scheme in the design of the UAV control system. The TMO scheme enables high-level structuring together with design-time guaranteeing of accurate timings of various critical control actions with significantly smaller efforts than those required when using lower-level structuring schemes based on direct programming of threads, UDP invocations, etc. Our system was validated by use of environment simulator developed based on an open source flight simulator named FlightGear. The TMO-structured UAV control software running on a small computing platform was easily connected to a simulator of the surroundings of the control system, i.e., the rest of the UAV and the flight environment. Positive experiences in both the TMO-structured design and the validation are discussed along with potentials for future expansion in this paper.

• The Transactions of the Korea Information Processing Society
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• v.7 no.2S
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• pp.733-743
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• 2000

This paper describes design and implementation of a content manager in the Integrated Steaming Framework Architecture (ISSA) that is proposed by the authors. The ISSA can provide an environment to develop multimedia streaming applications under heterogeneous distributed systems. The goal of ISSA is to extend the limitations of existing streaming systems. It can support diverse media formats and high level programming environment for streaming application developers. Moreover, it is independent from underlying networks and operating systems, and compatible with the global real-time multimedia database system(BeeHive) so that streaming media is efficiently retrieved, stored, and serviced. The role of a content manager is important in the ISSA environment since it manages an information of media that are provided by the server, and allow users to access media more easily by means of conveying that information to the streaming server, Web server, and client efficiently. The proposed content manager is not only to meed these requirements, but also to provide streaming information to media source and transport manager in order to be an efficient streaming. Furthermore, it supports database transaction processing by using the database connector.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.3
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• pp.592-606
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• 2011

Currently, the development of multimedia communication has progressed so rapidly that the video program service has become a requirement for ordinary customers. The quality of experience (QoE) for the visual signal is of the fundamental importance for numerous image and video processing applications, where the goal of video quality assessment (VQA) is to automatically measure the quality of the visual signal in agreement with the human judgment of the video quality. Considering the codec effect to the video quality, in this paper an efficient non-reference (NR) VQA algorithm is proposed which estimates the video quality (VQ) only by utilizing the distorted video signal at the destination. The VQA feature vectors (FVs) which have high relationships with the subjective quality of the distorted video are investigated, and a hybrid NR VQA (HNRVQA) function is established by considering the multiple FVs. The simulation results, testing on the SDTV programming provided by VCEG Phase I, show that the proposed algorithm can represent the VQ accurately, and it can be used to replace the subjective VQA to measure the quality of the video signal automatically at the destinations.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.146-148
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• 2001

This paper discusses the optimal sizes of BESS. The goal must be optimized electricity charge of the customers-side with choosing the time-of-use rates. Therefore the cost is minimized by BESS installed the customers-side. Feasible ROR that means the ratio of capital costs to economic effect owned the optimal BESS sizes is determined the suitable domestic condition based on the battery cost and power converter system cost. Payback period times can be presented by BESS through the ROR. Multi-Pass Dynamic Programming(MPDP) algorithm is applied to the customer for the optimal sizes determination in this paper. It is to solve the optimal solution under the constraints. To investigate the efficiencies of the constraints, it is applied the typical load curve to the high-voltage customer owned Time-Of-Use(TOU) whether BESS is installed or not. Well, The result is obtained that feasible BESS sizes can be achieved the suitable customers-side of meter through the ROR.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.315-317
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• 2001

This paper studies for the optimal operation of BESS. The goal must be optimized electricity charge of the customer sides owned time-of-use rates in this paper. Therefore, the least of cost is caused by BESS installation, Multi-Pass Dynamic Programming (MPDP) algorithm is applied to the customer for the optimal operation determination in this paper. It is to solve the optimal solution under the constraints. No matter how become one stage in general, problem is divided into several stage in series in this algorithm. Regardless of the decision step, MPDP is only accomplished based on the state of stage in the present. To investigate the efficiencies of the algorithm, it is applied the typical load curve to the cutomer owned Time-Of-Use(TOU). Result shows that the maximun economic benefits of the battery energy storage system can be achieved by the purposed algorithm.

• The Journal of Information Systems
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• v.7 no.1
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• pp.23-36
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• 1998

본 연구는 특정 조직의 정보 인프라 개발을 위한 전략적 계획을 수립하기 위해 의 사결정 지원 도구로서 다수 목표 의사결정 모형 (Multiple Objective Decision-Making Model : MODEM), 구체적으로는 목표 계획법(Goal Programming : GP)의 응용을 제시하고 있다. 연구대상 조직은 3년 동안의 정보 인프라 개발 프로젝트를 추진하고 있다. 이러한 특 별 프로젝트는 조직 전체에 궁극적인 통합 정보 기술 서비스를 제공하기 위하여 최고 의사 결정자의 전략적 계획 측면에서 추진되고 있다. 본 연구는 총 8개의 목표가 수립되었고 현 조직 환경하에서 이들 목포들에 대한 우선 순위가 설정되었다. Micro Manager가 본 연구 모형의 실행을 위하여 활용되었고 분석결과 6개의 정보 인프라 프로젝트 중 첫 5개가 실행 되기 위하여 선택되어 졌으며 4개의 네트? 대안 중에서 첫 번째 대안이 최적 대안으로 선 택되었다. 초기 설정 목표들에 대한 우선 순위를 변경시킴으로써 연구 모형의 가변성을 검 토하기 위해 민감도 분석이 실행되었다. 변경된 목표와 우선 순위하에서는 6개의 정보 인프 라 프로젝트 중 3개만이 실행을 위하여 선택되었고 네트? 대안은 첫 번째 대안이 역시 최 적 대안으로 선택되었다. 본 연구 모형은 다수의 서로 상층하는 목표를 가지는 조직 및 이 와 유사한 경영환경에 직면해 있는 전략적 의사결정 수립에 효과적인 방안을 제시할 것이다.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.5
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• pp.451-461
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• 2002

Differential evolution(DE) has been preyed to be an efficient method for optimizing real-valued multi-modal objective functions. DE's main assets are its conceptual simplicity and ease of use. However, the convergence properties are deeply dependent on the control parameters of DE. This paper proposes an adaptive differential evolution(ADE) method which combines with a variant of DE and an adaptive mechanism of the control parameters. ADE contributes to the robustness and the easy use of the DE without deteriorating the convergence. 12 optimization problems is considered to test ADE. As an application of ADE the paper presents a supervised clustering method for predicting events, what is called, an evolutionary event clustering(EEC). EEC is tested for 4 cases used widely for the validation of data modeling.

• Journal of the military operations research society of Korea
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• v.31 no.2
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• pp.28-44
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• 2005

The previous studies approach the field artillery fire scheduling problem as deterministic and do not explicitly include information on the potential scenario changes. Unfortunately, the effort used to optimize fire sequences and reduce the total time of engagement is often inefficient as the collected military intelligence changes. Instead of modeling the fire sequencing problem as deterministic model, we consider a stochastic artillery fire scheduling model and devise a solution methodology to integrate possible enemy attack scenarios in the evaluation of artillery fire sequences. The goal is to use that information to find robust solutions that withstand disruptions in a better way, Such an approach is important because we can proactively consider the effects of certain unique scheduling decisions. By identifying more robust schedules, cascading delay effects will be minimized. In this paper we describe our stochastic model for the field artillery fire sequencing problem and offer revised robust stochastic model which considers worst scenario first. The robust stochastic model makes the solution more stable than the general two-stage stochastic model and also reduces the computational cost dramatically. We present computational results demonstrating the effectiveness of our proposed method by EVPI, VSS, and Variances.