• Title/Summary/Keyword: Performance Quantity

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Design on Fixed Quantity Analytical Model for Information System Audit (정보시스템 감리의 정량화 분석 모델 설계)

  • Kim, Hee-Wan;Lee, Hae-Man;Kim, Dong-Soo
    • The Journal of the Korea Contents Association
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    • v.11 no.2
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    • pp.88-100
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    • 2011
  • This thesis suggests fixed quantity model and detailed performance procedures of an information system audit. In addition, an identification of the check-items with high operating risk and factors that might lead to serious effects on the business are made. Then, this thesis proposes the information system audit model that can grant priorities. By using this model, the orderer can evaluate objectively with digitized mark. The model can improve the effectiveness, reliability, and objectivity of the audit by minimizing the discrepancies of different opinions about audit evaluation results between auditee and the orderer. The proposed model is adapted to an application system and audit projects of the database construction. As a result, the model has received an equal mark from the result of the general reviews, thus the propriety of the proposed model was verified.

Numerical Study on the Effect of Nozzle Geometry on the Small CRDI Engine Performance (노즐 형상 변경이 소형 CRDI 엔진의 성능에 미치는 영향에 대한 수치 해석적 연구)

  • Min, Se Hun;Suh, Hyun Kyu
    • Journal of ILASS-Korea
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    • v.20 no.4
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    • pp.254-260
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    • 2015
  • The objective of this study is to investigate the effect of multi-hole nozzle on the performance of small CRDI engine. Combustion and exhaust emission characteristics of engine were studied by using CFD simulation with ECFM-3Z combustion model. The conditions of simulation were varied with nozzle geometry, injection timing and injection quantity. In addition, the results were compared in terms of combustion pressure, rate of heat release, $NO_x$ and soot emissions. It was found that combustion pressure was increased when injection timing was advanced. The rate of heat release of 6 hole nozzle was higher than that of 12 hole nozzle since the quantity of fuel impinged at the bottom of piston rim was different under different injection timing conditions. In the case of $NO_x$ emission, 6 hole nozzle generated more $NO_x$ emission than 12 hole nozzle. On the other hand, in the case of soot emission, 12 hole nozzle showed higher value than 6 hole nozzle because injected fuel droplets from multi-hole nozzle were coalesced.

An Empirical Analysis on Optimal Oder Quantity of Perishable and Seasonal Products : A Practical Application of Newsvendor Model in Retail (신선·시즌 상품의 최적 주문량 산정 문제에 대한 실증적 분석 : 소매유통업에서 뉴스벤더 모델의 적용)

  • Noh, Geon-Ho;Hwang, Seung-June
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.42 no.1
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    • pp.41-54
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    • 2019
  • Although retailers deals with a large number of single-term inventory items, but few cases have been considered in the areas of practical decision making. However, recent moves to strengthen fair trade have created a real need for single-period inventory decision-making problems. This study addresses the problem of ordering quantity decisions that are expected to maximize profits using classical newsvendor models. The research target is data on seasonal and perishable products from retail. We also use data from retailers to actually apply the newsvendor model and calculate the results to compare performance. It also suggests solutions for estimating demand for products sold in order to apply newsvendor models that utilize actual demand ratio versus forecast demand. This study would like to examine the effectiveness of this research through data analysis and make some suggestions for applying it to reality.

Self-Healing Performance of Concrete Using Admixture (구체방수 콘크리트의 균열 자가치유 성능)

  • Lee, Jong-Yun;Lee, Han-Joo;Lee, Yong-Jin
    • Journal of the Korean Society of Safety
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    • v.27 no.6
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    • pp.109-114
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    • 2012
  • This study is the things to experiment and evaluate the performance of self-healing water-proofing on the concrete to be using the crystal growth composite waterproofing admixture. The cylinder to be making on the concrete by ${\varnothing}150{\times}300$ mm for evaluating the performance of self-healing water-proofing was aging 90 days and cut on a 50 mm. So, it prompted the crack and applied. After it measured the quantity of water to be flow the water throughout the crack part of the cylinder, it applied the basic formular of Darcy's law and calculated the coefficient of water permeability. So, it verified the performance of self-healing water-proofing on the basis of the changing shape of the water permeability. This experiment is the thing to be applied the general evaluation of the structure to demand the real watertightness on doing for the evaluating of performance of the quantity of water leak and self-healing water-proofing about the various penetration crack.

Performance Comparison of Automotive Air conditioning System by using R134a and R152a (R134a와 R152a 냉매를 이용한 자동차용 에어컨 시스템의 성능 비교)

  • Kim, Jeong-Su;Nam, Su-Byung;Lee, Dae-Woong;Yoo, Seong-Yeon;Kim, Jin-Hyuck
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.9-14
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    • 2006
  • This study presented the feasibility of R152a refrigerant as an alternative of R134a which is used in the current automobile air conditioning system. The performance of air conditioning system installed in the actual vehicle was tested using the climate wind tunnel. The experiments were conducted at various refrigerant charge quantities and various driving conditions such as city traffic, highway traffic and parking. Same components and lubricant were used for both R134a and R152a system. The effects of air set values of thermal expansion valve on the performance were also investigated. In case of the R152a system, refrigerant charge quantity can be reduced about 20%, better performance and superior compressor durability is expected due to the lower discharge pressure compared to the R134a system.

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An Experimental Study on the Improvement of Durability of Dam Concrete (댐콘크리트의 내구성 향상에 관한 실험적 연구)

  • 윤영수;원종필;송영철;우상균;송유신
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.415-420
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    • 1999
  • Dam concrete should have sufficient durability in wet and dry repetition and abrasion due to water lever variance and also in freezing and thawing resistance as well as water penetration capacity. This study presents various experimental performance to enhance the durability of face slab concrete in concrete face rockfill dam by varying the fly ash substitution of 0%, 10%, 15% and 20% in cement quantity. The effect on durability corresponding to the increasing amount of fly-ash was evaluated and the optimum quantity of fly-ash subtitution was finally recommended. The results show that 15% fly-ash substituion was found out to be an optimum quantity and demonstrated an excellent performances in durability.

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Implemented Circuits of Fuzzy Inference Engine for Servo Control by using Decomposition of $\alpha$-Level Set ($\alpha$-레벨 집합 분해에 의한 서보제어용 퍼지추론 연산회로 구현)

  • Hong Jeng-pyo;Hong Soon-ill
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.54 no.2
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    • pp.90-96
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    • 2005
  • This paper presents hardware scheme of fuzzy inference engine, based on α-level set decomposition of fuzzy sets for fuzzy control of DC servo system. We propose a method which is directly converted to PWM actuating signal by a one body of fuzzy inference and defuzzification. The influence of quantity α-levels on input/output characteristics of fuzzy controller and output response of DC servo system is investigated. It is concluded that quantity α-cut 4 give a sufficient result for fuzzy control performance of DC servo system. The experimental results shows that the proposed hardware method is effective for practical applications of DC servo system.

Posture and activity monitoring using a 3-axis accelerometer (3축 가속도 센서를 이용한 자세 및 활동 모니터링)

  • Jeong, Do-Un;Chung, Wan-Young
    • Journal of Sensor Science and Technology
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    • v.16 no.6
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    • pp.467-474
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    • 2007
  • The real-time monitoring about the activity of the human provides useful information about the activity quantity and ability. The present study implemented a small-size and low-power acceleration monitoring system for convenient monitoring of activity quantity and recognition of emergent situations such as falling during daily life. For the wireless transmission of acceleration sensor signal, we developed a wireless transmission system based on a wireless sensor network. In addition, we developed a program for storing and monitoring wirelessly transmitted signals on PC in real-time. The performance of the implemented system was evaluated by assessing the output characteristic of the system according to the change of posture, and parameters and acontext recognition algorithm were developed in order to monitor activity volume during daily life and to recognize emergent situations such as falling. In particular, recognition error in the sudden change of acceleration was minimized by the application of a falling correction algorithm

Optimum Design Condition of the Collins Cryocooler (Collins 내동기의 최적 설계조건)

  • Lee, S.W.;Kim, S.Y.;Jung, P.S.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.4 no.3
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    • pp.183-190
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    • 1992
  • The Collins cryocooler is numerically analysed with the optimization technique, and the optimum operating and design conditions are searched. This paper shows that liquefied helium quantity has an external maximum w.r.t. the total mass flow rate, the mass flow rates through expander and the capacities of heat exchangers. The liquefied helium quantity increases as the compressor exit pressure of the cryocooler does. The maximum quantity of liquefied helium and the maximum coefficient of performance have been found to exist in extremum, depending on the ratios of each heat exchanger capicities to the total one. At the optimum condition, the capacity of heat exchanger in high temperature region is larger than that in low temperature region.

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APPLICATION OF KNOWLEDGE MANAGEMENT IN BUILDING AUTOMATION SYSTEM: A CASE STUDY OF SIX BUILDINGS IN KUALA LUMPUR

  • Nurul Afida Isnaini Janipha;Hamimah Adnan;Fadzil Hassan
    • International conference on construction engineering and project management
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    • 2007.03a
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    • pp.672-683
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    • 2007
  • The rapid development of Kuala Lumpur has seen numerous new and high-rise buildings introducing Building Automation System (BAS). Whilst effective application of Knowledge Management (KM) within BAS is the pre-requisite for the achievement of optimum BAS performance, there has been little research undertaken to investigate if have been the case. This paper presents a research undertaken to get a view of how KM applies in BAS in six (6) selected case-study buildings in Kuala Lumpur, all operating with the 'one-system' M&E workstation control BAS. The emergent findings positively suggest that adequate KM approaches were employed within their BAS management processes, but further studies would be necessary to determine the extent of their application and effectiveness.

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