• Title/Summary/Keyword: System Performance Improvement

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The Study of Performance Improvement Expectation for Purchasing by Adopting E-Procurement System (호텔 전자조달시스템의 도입이 구매성과기대에 미치는 연구)

  • Jang, Hyun-Jong;Oh, Soon-Whan
    • The Journal of the Korea Contents Association
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    • v.10 no.10
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    • pp.429-439
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    • 2010
  • The objective of this study is to show how much it could impact improvement expectation by adopting E-procurement system. Based on literature review, the following hypotheses were proposed: H1; The level of perception for adopting E-procurement system will be different by hotel's grade, the number of hotel rooms, types of Management, the number of employees. H2; Perception for adopting E-procurement system will influence improvement expectation of food material purchasing, beverage material purchasing, Room guest supplies & cleaning supplies, general material purchasing. H2-1, H2-2, H2-3, H2-4; Perception for adopting E-procurement system will differently influence improvement expectation of food material purchasing, beverage material purchasing, Room guest supplies & cleaning supplies, general material purchasing by job level and job performance. As a result, perception for adopting E-procurement system is in proportion to improvement expectation of purchasing and hypotheses related with job level and job performance which are moderating variables were accepted partially.

Performance Improvement and Envelope Variation Reduction of Multi-Code Parallel Combinatory CDMA Systems Using Bi-Orthogonal Modulation (Bi-Orthogonal Modulation을 이용한 Multi-code Parallel Combinatory CDMA System의 성능 개선 및 진폭 변동 감소 방안)

  • 임승환;신요안
    • Proceedings of the IEEK Conference
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    • 2000.09a
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    • pp.951-954
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    • 2000
  • In this paper, we present a multi-code parallel combinatory CDMA system using bi-orthogonal modulation to reduce envelope variation and improve bit error. .rate (BER) performance. In general, the dynamic range of the amplitude of the transmit signal is very large in the case of conventional multi-code CDMA systems, resulting in severe nonlinear distortion due to high power amplifier and thus significant BER performance degradation. The proposed system exhibits reduction of peak-to-average power ratio (PAPR) of the transmit signal amplitudes and significant performance improvement. We verify the performance of the proposed system by computer simulations under AWGN channel and flat fading channel.

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The intermediate Effects of Control System on the Relationship between Quality Strategy and Performance (품질전략과 경영성과간의 관계에서 통제시스템의 매개효과)

  • 김달곤
    • Journal of Korean Society for Quality Management
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    • v.30 no.3
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    • pp.150-167
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    • 2002
  • Normative theory suggests that control systems should be designed to complement management's objectives and strategies. However, few empirical studies have focused on how control systems have been modified to complement new manufacturing techniques, such as zero-defect strategy. The major purpose of this study is to examine the effects of the attributes of quality strategy and control system on performance. The previous studies have subdivided quality strategy into the ECL(economic conformance level) and ZD(zero-defect) strategy. To accomplish the purpose, this study empirically analysed the data based on the questionnaires from manufacturing department personnel of 67 Korean companies. The major results are as follows. The companies that had implemented the ZD strategy and its control system outperformed the companies that had implemented ECL strategy. Also, the ZD strategy differs from ECL strategy in control system, the criteria of performance evaluation and feedback frequence variable. There is no difference in quality performance monitoring and communication variable. From this results, although many companies have strived for continuous improvement of quality, it was restricted in improvement activities that dont's required much investment cost, quality performance monitoring and communication.

A Study on Refrigeration Performance of Vehicle HVAC System for Sub-Cooling Improvement (서브쿨링향상을 위한 차량공조 시스템의 냉방성능에 관한 연구)

  • 박만재
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.1
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    • pp.1-9
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    • 2004
  • The general method which changes sub-cooling of refrigerant is to control the expansion valve in the state of mixing with liquid and gas phase. In this study, the performance of vehicle air conditioning system is to control either changing the expansion valve or adding the sub condenser. Therefore, this research finally is tested in case of the fourth test procedure, the second test was suitable for a valve opening area due to adjusting valve slope in comparison with the other test. The other test except for the second test happened to do liquid back due to the excessively liquified refrigerant into the system. In conclusion, the second test was appeared not to be influenced upon liquid back, and it is to expect positive performance by controlling an expansion valve. Therefore, it will be also useful to research for an increase of compressor efficiency Performance improvement of an air conditioner is to reinforce the suction performance of the evaporator and increase the sub-cooling, which make use of the sub-cooling system.

Performance Analysis of OFDM System Considering Carrier Frequency Offset in Wireless LAN Channel Environment

  • Kim, Ji-Woong;Kang, Heau-Jo;Lee, Kwon-Hyun
    • Journal of information and communication convergence engineering
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    • v.2 no.1
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    • pp.1-4
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    • 2004
  • In this paper, We analyzes how a synchronization error affects receiving system when using OFDM(Orthogonal Frequency Division Multiplexing) transmission method in wireless LAN channel environment in which we can efficiently transmit wide-band information data. As a performance improvement method, performance distortion can be improved by applying convolution coding. As a result, in OFDM system, we could see that the higher a frequency offset is, the worse performance will be, and we could see that there was performance improvement by applying convolution coding in OFDM system in order to reach (BER=$10^{-3}$). However, when we use 64QAM (64Quadrature Amplitude Modulation), there was a huge influence between carriers by frequency offset at 0.05, 0.1.

CONTROL PERFORMANCE IMPROVEMENT OF AN EMV SYSTEM USING A PM/EM HYBRID ACTUATOR

  • Ahn, H.J.;Chang, J.U.;Han, D.C.
    • International Journal of Automotive Technology
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    • v.8 no.4
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    • pp.429-436
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    • 2007
  • In this study, we improved control performance of an EMV (electromechanical valve) system using a PM/EM (permanent magnet/electromagnet) hybrid EMA (electromagnetic actuator) and showed the feasibilities of both soft landing and fast transition of the EMV system using a simple PID control. The conventional EMV systems using only EM show significant nonlinear characteristics. Therefore, it is very difficult to control the valve position and several complex control schemes are used. This paper focused on the control performance improvement using a PM/EM hybrid actuator. In particular, a PM is used as a key design parameter such as a bias current of a magnetic bearing in order to improve the linear characteristic of the actuator, although most PM/EM hybrid actuators use a PM as a power saver during valve-open and -closed states. First, a FE (finite element) analysis was performed to confirm its linear static force characteristics. Then, both a test rig and a valve control system were built in order to prove experimentally the control performance improvement of the actuator. Finally, feasibilities of both soft landing and fast transition of the system were shown experimentally through gain-scheduled PID (proportional derivative integral) control.

A Study on case of the Quality Management System and Performance Improvement (품질경영시스템 개선 방법에 관한 사례 연구)

  • Kim Jong-Gurl;Kim Chang-Soo
    • Proceedings of the Safety Management and Science Conference
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    • 2006.04a
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    • pp.437-445
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    • 2006
  • ISO 9000 is a management standard that provides customers with assurance thu their registered suppliers have a consistent quality system to which they adhere. this paper draws on four sources to show how ISO 9000 can lead to performance improvement. 1)theories of induces innovation and improvisation 2) the literature on ISO 9000 3) a case study of a telecom company. we find that the extent to which ISO 9000 is associated with performance improvement depends on the level of its assimilation, and the degree to which an organization goes beyond the minimal requirements of the standard.

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A study on effects of ISO/TS 16949 quality management system on customer satisfaction and organizational performance (ISO/TS 16949 품질경영시스템이 고객만족과 조직성과에 미치는 영향에 관한 연구)

  • Kim, Min-Kyeong;Kang, Kyung-sik
    • Journal of the Korea Safety Management & Science
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    • v.19 no.1
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    • pp.145-156
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    • 2017
  • This study was conducted to grasp problems of the present and investigate the real condition of organizations by making how an organizational ISO/TS 16949 quality management system has a positive effect on process improvement, perceived organizational support has a significant effect on the relationship between ISO/TS 16949 requirements and process improvement, process improvement has a positive effect on customer satisfaction and organizational performance research projects. For doing them, it tris to suggest an effective application plan of ISO/TS 16949 certification through improvements about corporate quality management systems of the automobile field by investigating and analyzing literature of the precedent studies and ISO/TS 16949 certification effects actually, conducting and analyzing an survey on effects on customer satisfaction and organizational performance, and drawing the problems.

Performance Improvement of MIMO MC-CDMA system with multibeamforming

  • Kim, Chan Kyu
    • International Journal of Internet, Broadcasting and Communication
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    • v.11 no.2
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    • pp.76-83
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    • 2019
  • In this paper, we propose the beamforming algorithm for the performance improvement of MIMO MC-CDMA system. The proposed multibeamforming of MIMO MC-CDMA structure having the same number of beamformer as the number of transmit antenna is derived by calculating the error signals between the coded pilot symbols and the corresponding received signals from the multiple transmitters of the desired user in the frequency domain, transforming the frequency-domain error signals into time-domain error signals, and updating the weights of the multibeamformer in the time-domain in the direction minimizing the mean squared error (MSE). The proposed approach can track each direction of arrival (DOA) of the signals from multi-antennas of a desired user. The performance improvement is investigated through computer simulation by applying the proposed approach to MIMO MC-CDMA system in a multipath fading channel with multiusers.

Performance Improvement of Multi-Code Parallel Combinatory CDMA Systems Using Bi-Orthogonal Modulation under Multipath Fading Environment (다중 경로 페이딩 채널에서 Bi-orthogonal Modulation을 이용한 Multi-code Parallel Combinatory CDMA System의 성능 개선)

  • 임승환;신요안
    • Proceedings of the IEEK Conference
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    • 2000.11a
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    • pp.245-248
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    • 2000
  • In this paper, we present the performance of a multi-code parallel combinatory CDMA system using bi-orthogonal modulation under multipath fading channel. In general, the dynamic range of the amplitude of the transmit signal is very large in conventional multi-code CDMA systems, resulting in severe nonlinear distortion due to high power amplifier and thus significant BER performance degradation. Since the number of simultaneously multiplexed code channels in the proposed system is reduced, the proposed system exhibits reduction of peak-to-average power ratio (PAPR) of the transmit signal amplitude with significant BER improvement. We verify the performance of the proposed system by computer simulations under the Vehicular B multipath fading channel model by ARIB.

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