• Title, Summary, Keyword: Performance index

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Calculation of Seismic Capacity Evaluation Index of Shear Wall System (전단벽 구조시스템의 내진성능평가 지표 산정)

  • Park, Tae-Won;Na, Seong-Uk;Woo, Woon-Taek;Chung, Lan
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.223-230
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    • 2002
  • Earthquake resistance design has been developed many countries like Japan, USA, Mexico, New Zealand etc., which countries have experienced many earthquakes. Nowadays, earthquake resistance design has come into worldwide use. In Korea, the seismic design regulations have been established since 1988 in order to minimize the economic losses. Recently performance based design method has been adopted as a new Earthquake resistance design method. These regulations, however, are targeted for newly constructed buildings, In Korea, there are no regulations for existing buildings that built before 1988. On the other hand, in Japan and USA, the seismic performance evaluation is coded. In Japan, the evaluation index which can measure seismic performance has been made. So, we need to prepare the regulations that evaluate the seismic performance, furthermore proper retrofitting design guideline needs to be proposed when remodeling old buildings. In this research, various seismic performance evaluation methods which are being used in Japan and USA are reviewed in order to establish seismic performance evaluation index for those existing old structures in Korea.

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Comparative Analysis on Performance Indices of Obstacle Detection for an Overlapped Ultrasonic Sensor Ring (중첩 초음파 센서 링의 장애물 탐지 성능 지표 비교 분석)

  • Kim, Sung-Bok;Kim, Hyun-Bin
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.4
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    • pp.321-327
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    • 2012
  • This paper presents a comparative analysis on three different types of performance indices of obstacle detection for an overlapped ultrasonic sensor ring. Due to beam overlap, the entire sensing zone of each ultrasonic sensor can be divided into three smaller sensing subzones, which leads to significant reduction of positional uncertainty in obstacle detection. First, the positional uncertainty in obstacle detection is expressed in terms of the area of a sensing subzone, and type 1 performance index is then defined as the area ratio of side and center sensing subzones. Second, based on the area of a sensing subzone, type 2 performance index is defined taking into account the size of the entire range of obstacle detection as well as the degree of the positional uncertainty in obstacle detection. Third, the positional uncertainty in obstacle detection is now expressed in terms of the length of the uncertainty arc spanning a sensing subzone, and type 3 performance index is then defined as the average value of the uncertainty arc lengths over the entire range of obstacle detection. Fourth, using a commercial low directivity ultrasonic sensor, the changes of three different performance indices depending on the parameter of an overlapped ultrasonic sensor ring are examined and compared.

Low Sensitive Optimal Steering System of Ships at Sea (저감도최적조타계의 설계에 관한 연구)

  • 이철영
    • Journal of the Korean Institute of Navigation
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    • v.4 no.1
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    • pp.19-30
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    • 1980
  • The usual procedure for the optimal design of ship's steering system is to minimize a chosen quadratic performance index, which isdetermined from the view point of economic run. However, the optimal control synthesized in such a straightforward fashion is unsatisfactory because ship's parameters differ from their nominal values due to uncertainties and errors in measurement and/or simplifications in mathematical modelling, and/or the variation of the ship's loading condition. In an attempt to resolve this difficulty, this paper presents a method for designing a low sensitive optimal steering system in a way as to minimize not only given performance index but also the sensitivity of the performance index and trajectory sensitivity. It is also shown that the optimal control so obtained will result in a system whose performance index and transient response are low sensitive to small varation in ship's time constant.

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Fuel Economy Optimization of Hybrid Vehicle Using Single Performance Index (단일 성능지수를 이용한 하이브리드 차량의 연비 성능 최적화)

  • Cho, Sung-Tae;Jun, Soon-Il;Kong, Jin-Hyung;Park, Yeong-Il;Lee, Jang-Moo
    • Proceedings of the KSME Conference
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    • pp.552-557
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    • 2001
  • To minimize the fuel consumption in the hybrid vehicle, the single performance index, which can express the fuel consumption in engine and electric energe consumption in battery system at the same time, is required. In this study we proposed a single performance index with equivalent BSFC concept, and with this, we constructed driving control algorithm, which can determine optimal gear ratio and power split ratio of the engine and the motor, for the parallel hybrid vehicle. Additionally, to verify the validity of this algorithm, driving simulation is performed.

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A Column-Aware Index Management Using Flash Memory for Read-Intensive Databases

  • Byun, Si-Woo;Jang, Seok-Woo
    • Journal of Information Processing Systems
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    • v.11 no.3
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    • pp.389-405
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    • 2015
  • Most traditional database systems exploit a record-oriented model where the attributes of a record are placed contiguously in a hard disk to achieve high performance writes. However, for read-mostly data warehouse systems, the column-oriented database has become a proper model because of its superior read performance. Today, flash memory is largely recognized as the preferred storage media for high-speed database systems. In this paper, we introduce a column-oriented database model based on flash memory and then propose a new column-aware flash indexing scheme for the high-speed column-oriented data warehouse systems. Our index management scheme, which uses an enhanced $B^+$-Tree, achieves superior search performance by indexing an embedded segment and packing an unused space in internal and leaf nodes. Based on the performance results of two test databases, we concluded that the column-aware flash index management outperforms the traditional scheme in the respect of the mixed operation throughput and its response time.

Optimization of trusses under uncertainties with harmony search

  • Togan, Vedat;Daloglu, Ayse T.;Karadeniz, Halil
    • Structural Engineering and Mechanics
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    • v.37 no.5
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    • pp.543-560
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    • 2011
  • In structural engineering there are randomness inherently exist on determination of the loads, strength, geometry, and so on, and the manufacturing of the structural members, workmanship etc. Thus, objective and constraint functions of the optimization problem are functions that depend on those randomly natured components. The constraints being the function of the random variables are evaluated by using reliability index or performance measure approaches in the optimization process. In this study, the minimum weight of a space truss is obtained under the uncertainties on the load, material and cross-section areas with harmony search using reliability index and performance measure approaches. Consequently, optimization algorithm produces the same result when both the approaches converge. Performance measure approach, however, is more efficient compare to reliability index approach in terms of the convergence rate and iterations needed.

A Quantitative Performance Index for an Input Observer (II) - Analysis in Steady-State - (입력관측기의 정량적 성능지표 (II) -정상상태 해석-)

  • Jung, Jong-Chul;Lee, Boem-Suk;Huh, Kun-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.10
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    • pp.2067-2072
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    • 2002
  • The closed-loop state and input observer is a pole-placement type observer and estimates unknown state and input variables simultaneously. Pole-placement type observers may have poor performances with respect to modeling error and sensing bias error. The effects of these ill-conditioning factors must be minimized for the robust performance in designing observers. In this paper, the steady-state performance of the closed-loop state and input observer is investigated quantitatively and is represented as the estimation error bounds. The performance indices are selected from these error bounds and are related to the robustness with respect to modeling errors and sensing bias. By considering both transient and steady-state performance, the main performance index is determined as the condition number of the eigenvector matrix based on $L_2$-norm.

Development of Performance Indicators Based on Balanced Score Card for School Food Service Facilities (균형성과표(BSC)개념을 적응한 학교급식 운영성과 측정지표 개발)

  • Kwak, Tong-Kyung;Chang, Hye-Ja;Song, Ji-Yong
    • Korean Journal of Community Nutrition
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    • v.10 no.6
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    • pp.905-919
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    • 2005
  • This study raised the necessity of developing performance indicators for measuring the management efficiency and effectiveness of school food service, and as a means of helping its implementation, a balanced score card (BSC) approach developed by Norton and Kaplan was adopted. This study established BSC in seven phases through literature: Phase 1 Defining a school food service and the scope of working activities, Phase 2 Establishing the vision of a school food service, Phase 3 Setting strategic goals, Phase 4 Identifying critical success factors (CSFs), Phase 5 Developing Key Performance Indicators (KPIs), Phase 6 Extracting cause and effect relationship, and Phase 7 Completing a preliminary BSC. The preliminary BSC was fumed into a survey, which was administered to food service related people working at the Office of Education and School Food Service including 16 offices,209 dietitians, 48 school administrators both from self-operated and contract-managed, and 9 experts in areas related to school food service. They were asked questions about strategies from 4 different perspectives,12 CSFs, 39 KPls, and the cause and effect relationships among them. As a result, among the CSFs based on 4 different perspectives, all factors other than ' zero sum on profit/loss ' from the financial perspective turned out to be valid. In terms of KPIs, manufacturing cost percentages, casualty loss count/reduction rates, school foodervice participation rates, and sales goal achievement rates were found to be valid from the financial perspective, while student satisfaction index, faculty satisfaction index, leftover ratio, nutrition educational performance count, index of evaluating nutrition education, customer claim count/reduction rate, handling customer claim count/reduction rate, and parent satisfaction index were found to be valid from the customers' perspective. Besides, nutritional requirement sufficient ratio, nutritional management score, food poisoning outbreak count, employee safety accident count, sanitary inspection assessment index, meals per labor hour (productivity index), computerization ratio, operational management index, and purchase management assessment index were also found to be valid from the perspective of internal business processes. From the perspective of innovation and learning, employee turnover ratio/rate of absenteeism, annual education and training count, employee satisfaction index, human resource management assessment index, annual menu-related customer feedback, food service information index for employees and parents/schools were also found to be valid. The significance of this study is to present indices for measuring overall performance of school lunch food service operations without putting any limitation on types of school food service management, and to help correctly assess the contribution of the current types of school food service management to schools and students. (Korean J Community Nutrition 10(6) : $905\∼919$, 2005)

Performance Study of the Index-based Parallel Join

  • Jeong, Byeong-Soo;Edward Omiecinski
    • The Journal of Information Technology and Database
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    • v.2 no.2
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    • pp.87-109
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    • 1995
  • The index file has been used a access database records effectively. The join operation in a relational database system requires a large execution time, especially in the case of handling large size tables. If the indexes are available on the joining attributes for both relations involved in the join and the join selectivity is relatively small, we can improve the execution time of the join operation. In this paper. we investigate the performance trade-offs of parallel index-based join algorithms where different indexing schemes are used. We also present a comparison of our index-based parallel join algorithms with the hash-based parallel join algorithm.

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Search Performance Improvement of Column-oriented Flash Storages using Segmented Compression Index (분할된 압축 인덱스를 이용한 컬럼-지향 플래시 스토리지의 검색 성능 개선)

  • Byun, Siwoo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.1
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    • pp.393-401
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    • 2013
  • Most traditional databases exploit record-oriented storage model where the attributes of a record are placed contiguously in hard disk to achieve high performance writes. However, for search-mostly datawarehouse systems, column-oriented storage has become a proper model because of its superior read performance. Today, flash memory is largely recognized as the preferred storage media for high-speed database systems. In this paper, we introduce fast column-oriented database model and then propose a new column-aware index management scheme for the high-speed column-oriented datawarehouse system. Our index management scheme which is based on enhanced $B^+$-Tree achieves high search performance by embedded flash index and unused space compression in internal and leaf nodes. Based on the results of the performance evaluation, we conclude that our index management scheme outperforms the traditional scheme in the respect of the search throughput and response time.