• Journal of Power Electronics
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• v.16 no.6
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• pp.2162-2172
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• 2016

This paper presents a Direct Torque Control (DTC) strategy for the five-phase induction motor driven by a three-level five-phase inverter in order to improve the performance of the five-phase induction motor. In the proposed DTC technique, only 22 voltage vectors out of 243 available voltage vectors in a three-level five-phase inverter are selected and are divided in 10 sectors each with a width of $36^{\circ}$. The four different DTC combinations (DTC-I, II, III and IV) for a three-level five-phase induction motor drive are investigated for improving the performance of five-phase induction motor. All four of the DTC strategies utilize a combination of the same large and zero voltage vectors, but with different medium voltage vectors. Out of these four techniques, DTC-II gives the best performance when compared to the others. This DTC-II technique is analyzed in detail for improvements in the performance of five-phase induction motor in terms of torque ripple, x-y stator flux and Total Harmonics Distortion (THD) of the stator phase current when compared to its two-level counterparts. To verify the effectiveness of the proposed three-level five-phase DTC control strategy, a DSP based experimental system is build. Simulation and experimental results are provided in order to validate the proposed DTC technique.

• Asia pacific journal of information systems
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• v.7 no.2
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• pp.103-135
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• 1997

Today, many organizations are reengineering themselves to develop new ways to thrive in a foreign and unforgiving business environment. However, it is reported that many companies involved in the project of business process reengineering are dissatisfied with their results. Therefore, we developed an exploratory framework based on three constructs such as critical success factors, organizational maturity level, and performance and applied these to help analyze current practice in business process reengineering. To proceed with our research, this paper was organized around two research questions in business process reengineering. We addressed: (1) To what extent does certain critical success factors correlate with performance? and (2) How does the relationships between critical success factors and performance differ by organizational maturity level? From the research results, we could find relationships between critical success factors(i.e., project management, change management, objective management) and performance, and could verify differences in performance of organizations grouped by organizational maturity level.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2003.11a
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• pp.73-76
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• 2003

This paper is contents about method to measure interception performance of shock noise of floor slab of apartment house to be simple. In the case of interception performance of light floor impact sound level, according to measurement method, grade of sound insulation performance showed greatly differently. But, in the case of interception performance of heavy floor impact sound level, it was similar result in all measurement method. Therefore, use of simple method of measurement was examined by possible fact in case of interception performance of heavy floor impact sound level.

• Korean Journal of Materials Research
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• v.17 no.7
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• pp.347-351
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• 2007

Vertical interconnect technology called 3D stacking has been a major focus of the next generation of IC industries. 3D stacked devices in the vertical dimension give several important advantages over conventional two-dimensional scaling. The most eminent advantage is its performance improvement. Vertical device stacking enhances a performance such as inter-die bandwidth improvements, RC delay mitigation and geometrical routing and placement advantages. At present memory stacking options are of great interest to many industries and research institutes. However, these options are more focused on a form factor reduction rather than the high performance improvements. In order to improve a stacked device performance significantly vertical interconnect technology with wafer level stacking needs to be much more progressed with reduction in inter-wafer pitch and increases in the number of stacked layers. Even though 3D wafer level stacking technology offers many opportunities both in the short term and long term, the full performance benefits of 3D wafer level stacking require technological developments beyond simply the wafer stacking technology itself.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1340-1345
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• 2009

Ministry of Land, Transportation and Maritime Affairs has implemented Construction CALS project for improving informationization level of construction industry and for making construction production system efficient. Although an importance of evaluation on level and performance of construction informationziation projects has been emerged, Construction CALS hasn't been evaluated so far. In this study, the performance indicators of construction CALS as the most important base in creating a performance management system were deduced. For this aim, this study reviewed the former researches on system construction for managing performance, analyzed current status of Construction CALS, arranged the relationship between upper strategies and ISP, developed pools of performance indicators, and this study followed IT BSC methodology. As a result, this study developed performance indicators of Construction CALS through four strategies such as globalization and activation of Construction CALS standards, research & development for reaching to international level in construction informationization technology, stabilization of system operation and distribution by publicizing Construction CALS and improving its functions, and policy implementation for managing and coordinating Construction CALS projects. These indicators will be applied to build a system of performance management.

• Journal of the Ergonomics Society of Korea
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• v.32 no.1
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• pp.37-45
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• 2013

Objective: This study describes the change of operator performance in drastic change of illumination level, and proposes an alternative method to cope with it. Background: The control standard of illumination for nuclear power plants(NPPs) is based on the set of limit criteria for maintaining a specific illumination level. However, there is a possibility to cause human errors according to the psychological and physiological influences to operators in the situation of drastic change of illumination such as SBO(Station Black Out), so a basic study is necessary to review the current approach. Method: We assessed the visual fatigue, subjective work load and task performance according to the three illumination situations(Normal Illumination, Emergency Illumination, and Drastic Change of Illumination). Result: Research finding shows that there are not significant differences in task performance between normal illumination (1,000lx level) and emergency illumination (100lx level), only if beyond the dark adaptation limit. However, subjective work load on mental demand and visual fatigue show a potential challenge to visual performance in drastic change of illumination. Conclusion/Application: Several trials can complement this challenge in NPPs by applying 3-way communication, enhancing readability of procedures, and managing the visual factors affecting the operators' performance through a Visual Environment Management Program including visual health aspects, etc.

• Health Policy and Management
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• v.6 no.1
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• pp.191-210
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• 1996

This study purported to acquire information necessary to improve the operational efficiency of general hospitals. It tried to determine major indices which represent managerial performance of general hospitals and to identify the managerial characteristics of general hospital which affect the major financial indices. 201 hospitals which were subject to standardization audit by the Korean Hospital Association were investigated and 80 hospitals were finally chosen for this study. Their financial and managerial data during the period between January 1991 and December 1991 were collected. Considering financial indices in this study were the ration of net income to total asset, income growth rate, and quick ration. The results of study are summarized as followings. First. The ration of net income to total assets and quick ration were highly related to managerial characteristics of general hospitals. Therefore, the standardization of three financial indices should be needed to systematically check the operational efficiency of general hospitals. Second, the sample hospitals can be classified as four groups on the basis of their financial indices' level. 4 of those hospitals(5.0%) showed high level of performance in terms of three financial indices and 27 of them(33.7%) showed that they are highly related to only two financial indices. 34 hospitals(42.5%) showed they have high level of relationship with only one indices and 15 hospitals(18.8%) showed very weak performance level with three indices. In addition, there is no hospitals to show mid-range level of managerial performance in relation to all three financial indices. Third, there is no significant relationship between three financial indices and the managerial characteristics of hospitals such as the number of beds, type of operation, location of hospitals, and etc. However, in the case of hospitals which have high level of managerial performance, they have more specialists and medical support personnel in comparison to low performance hospitals. They also have high level of bed occupancy rate and average length of stay(ALOS). In conclusion, the study showed the standardization of 3 financial indices are necessary to systematically evaluate the managerial performance of general hospitals and provide more accurate operational information for each hospital. To do so, it is necessary to focus on management side of hospital such as the effective human resource management and quality enhancement of medical treatment.

• Journal of the Korea Society of Computer and Information
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• v.26 no.7
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• pp.91-102
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• 2021

The effectiveness of informatization can vary depending on the level of operation of the information system as well as investment and installation. This study investigates and analyzes the information system operating environment and quality level of small and medium-sized manufacturing companies in Korea, and investigates how it affects the performance indicators of companies. The influence of the environmental factors operating the information system on the productivity performance and financial performance through the quality level of the information system was analyzed through the structural model. As a result of the analysis, it can be said that the higher the level of information system operating environment factors, the higher the quality level, the higher the quality level, the higher the productivity performance, and the higher the productivity performance, the higher the financial performance. It is judged that the effect of informatization depends on the operating environment and quality level after the installation of the information system.

• Nuclear Engineering and Technology
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• v.42 no.4
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• pp.460-467
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• 2010

In this study, the parameters of the feedwater control system (FWCS) of the OPR1000 type nuclear power plant (NPP) are optimized by response surface methodology (RSM) in order to acquire better level control performance from the FWCS. The objective of the optimization is to minimize the steam generator (SG) water level deviation from the reference level during transients. The objective functions for this optimization are relationships between the SG level deviation and the parameters of the FWCS. However, in this case of FWCS parameter optimization, the objective functions are not available in the form of analytic equations and the responses (the SG level at plant transients) to inputs (FWCS parameters) can be evaluated by computer simulations only. Classical optimization methods cannot be used because the objective function value cannot be calculated directely. Therefore, the simulation optimization methodology is used and the RSM is adopted as the simulation optimization algorithm. Objective functions are evaluated with several typical transients in NPPs using a system simulation computer code that has been utilized for the system performance analysis of actual NPPs. The results show that the optimized parameters have better SG level control performance. The degree of the SG level deviation from the reference level during transients is minimized and consequently the control performance of the FWCS is remarkably improved.

• Nuclear Engineering and Technology
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• v.32 no.2
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• pp.157-168
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• 2000

The nuclear steam generator level control system is designed by robust control methods. The feedwater controller is designed by three methods of the H$\infty$, the mixed weight sensitivity and the structured singular value. Then the controller located on the feedback loop of the level control system is designed. For the system performance, the controller of simple PID whose coefficients vary with the power is selected. The simulations show that the system has a good performance with proper stability margins.