• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.133-136
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• 1987

This paper presents a new algorithm of optimal measurement system by using band matrix characteristic respectively for state estimation. A performance index of measurement system is established to reflect relation among measurement sets, probability of measurement failure and cost of individual meter installation. Selection ranking in the candidates of measurement sets is composed to guarantee the observability for any any single meter outage. Performance index sensitivity is introduced and recursive formula which based on the matrix inversion lemma used for selection. The proposed algorithm is composed of successive addition algorithm, successive elimination algorithm and combinatorial algorithm. The band matrix characteristic could save in memory requirements and calculate the performance index faster than earlier.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.7
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• pp.944-949
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• 2012

As modern power systems become large and complicated, the automated voltage and reactive power control system is required in most developed countries due to the recent amazing progress of computer net works and information thechnology. So far the voltage control has been depend on human operator in korean power system. This paper presents an intelligent voltage control system based on sensitivity analysis and artificial intelligence technology. Detailed state space modeling technique is discussed and a new performance index is proposed to speed up the searching performance of the expert system. As the searching strategy is very important factor of the speed of expert system the least first search algorithm is applied using this performance index. The intelligent voltage control system is applied to the Jeju power system. As a result, case studies showed a promissing application of the intelligent voltage control system.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.238-240
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• 2002

If there is an Information Retrieval system which comprehends the semantic content of documents and knows the preference of users. the system can search the information better on the Internet, or improve the IR performance. Therefore we propose the IR model which combines semantic based indexing and fuzzy relevance model. In addition to the statistical approach, we chose the semantic approach in indexing, lexical chains, because we assume it would improve the performance of the index term extraction. Furthermore, we combined the semantic based indexing with the fuzzy model, which finds out the exact relevance of the user preference and index terms. The proposed system works as follows: First, the presented system indexes documents by the efficient index term extraction method using lexical chains. And then, if a user tends to retrieve the information from the indexed document collection, the extended IR model calculates and ranks the relevance of user query. user preference and index terms by some metrics. When we experimented each module, semantic based indexing and extended fuzzy model. it gave noticeable results. The combination of these modules is expected to improve the information retrieval performance.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.111-115
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• 2001

A good business performance measurement system is an effective tool io sustained growth in profits. Although interest in creating performance measurement models is widespread, a well-designed system is rare. To be successful in today's competitive environment, a performance measurement system should incorporate strategic success factors and contain financial and non-financial measuring index to carry out strategic management. In the 1990s, Kaplan & Norton introduced a concept called the Balanced Scorecard. The Balanced Scorecard supplements traditional financial measures with criteria that measured performance from three additional perspectives - those perspectives of customers, internal business processes, and learning and growth. This paper presents five measuring index criteria for each perspective. To calculate the relative priority for These measuring index, we investigate weights investigated by interviews with management consultant. Then, AHP method is employed for calculating priority weight. Our evaluation model may be referred to as the Balanced Analytic Hierarchical Performance Model(BAHPM) in the sense that the analytic hierarchical scheme, along with the AHP, is applied. The BAHPM is the first kind of analytical model to cover a wide variety of measures. In comparison with previous evaluation models, our model shows strengths in structural flexibility, ease of incorporating feedback, group evaluation capacity, participation promotion, sensitivity analysis, and computational simplicity. A prototype based on the BAHPM can be applied to various industry sectors.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2003.06a
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• pp.169-172
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• 2003

PID control has been well used for several decade. For PID algorithm, some tuning methods are used and with these parameters, control system is designed. But in some cases various kinds of performance are needed, so variable type of performance index must be utilized so that the designed control system meets the conditions. This paper presents some linear combinational type of performance index and with numerical methods, the PID parameters are obtained. Moreover I-PD type controller is used so that this two degree of freedom controller may give more desirable output characteristics. Simulations are done with MATLAB m file and mdl files.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1088-1093
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• 2009

To improve construction productivity and quality, and to make the construction environment safe, a new system, Robot-based Construction Automation (RCA), is currently being developed in Korea. To determine whether RCA is an improvement over traditional construction methods (TCMs), an evaluation method, called the Performance Evaluation Index (PEI), is suggested for RCA. The PEI considers the relationships among the factors influencing the performance of the system obtained using the Delphi method and the analytic hierarchy process (AHP). As the evaluation shows, RCA is much better than TCM except for three factors: the rate of work success, quality improvement by learning experience, and construction duration.

• Journal of the Korea Society of Computer and Information
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• v.27 no.12
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• pp.1-8
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• 2022

As an efficient file system for SSD(Solid State Drive), F2FS is employed in the kernel of Linux operating system. F2FS applies various methods to improve performance by reflecting the characteristics of flash memory. One of them is improvement of the index structure that contains addresses of data blocks for each file. This paper presents a method for further improving performance by modifying the index structure of F2FS. F2FS manages all index blocks as logical numbers, and an address mapping table is used to find the physical block addresses of index blocks on flash memory. This paper shows performance improvement by applying logical numbers to the last level index blocks only. The count of mapping table search for a data block access is reduced to 1~2 from 1~4.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.4
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• pp.52-60
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• 2017

This paper forces on the analysis of the overall outcome regarding Performance Based Logistics(PBL) application for Air Weapon System. We used data from domestically developed aircraft such as KT/A-1 and T-50 as well as data from foreign F-15K aircraft and F100 Engine to analyze the current ROKAF PBL application results. Furthermore, this paper thus suggests various techniques to maximize the outcome of user-based PBL performance such as clarifying the responsibility between customer and the company, developing standardized PBL performance index under TLCSM, PBL related maintenance capacity development, wartime PBL implementation process of domestic/foreign companies and many other schemes based on the analyzed data.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.3
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• pp.237-245
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• 2020

In this paper, I introduce Phase-Change Cooling for thermal management of high power devices that can be applied to High Power Laser and Electric Propulsion Systems which are composed of multiple distributed superheat sources. Phase-Change Cooling can be good used to efficient cooling of their heat sources. Phase-Change Cooling has extremely high efficiency of two-phase heat transport by utilizing heat of vaporization, relatively low flow rates and reduced pumps power. And I suggest TPI(Thermal Performance Index) which is a quantitative performance index of Phase-Change Cooling for thermal management. I quantify the performance of Phase-Change Cooling by introducing TPI. I present the test results of TPI's changing refrigerant, heat sink and flow rate of the Phase-Change Cooling system through the experiments and analyze these results.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.90-94
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• 2004

Among various modern control theories, PID control has been well used for several decades. PID algorithms needs son tuning methods are used for selecting PID parameters. But in some cases various kinds of performance indices are used instead of well-known tuning rules, and so variable type of performance index must be tested so that controllers, output characteristics and disturbance rejection property meets some specifications. In this paper, linear conbinational type of performance using error signal, time, control input and robustness is used to the PID control of air conditioning system. By the 2 DOF PID parmeters minimizing perfromacne index, controllers, output characteristics and robustness properties are analyzed. Simulations are done with MATLAB m file and mdl files.