• The KSFM Journal of Fluid Machinery
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• v.17 no.3
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• pp.52-58
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• 2014

The development of efficient systems for water quality improvement for water sources such as lakes, dams and reservoirs has become a necessity to provide not only a cleaner and safer water to the urban society, but also to provide a cleaner and safer environment for the aquatic organisms living in lakes, dams and reservoirs. This study concentrates on the outlet design and internal flow analysis of an axial flow pump used in a floating type water treatment system completely powered by renewable energy source. The treatment system is designed to raise water from depths of about 3~5m up to the water surface where it is naturally mixed with air as it is released back to the reservoir. The outlet of a typical axial flow pump is modified to suit the floating type water mixer. The performance of the axial flow pump is studied by investigating the internal flow of the system. Results show that the change in outlet shape does not alter the performance of the original pump at the maximum efficiency point as long as the cross sectional area of inlet is the same as the outlet. The axial pump for floating type water treatment system has good cavitation performance in the whole flow passage.

• Journal of Power System Engineering
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• v.11 no.3
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• pp.66-72
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• 2007

This study proposed new method to decide the reference model necessary for design PID controller. In generally, control design problems using the reference model have the following two factors. One factor is that numerical model of the controlled system can be obtained extremely, and the other is that specification for the closed-loop dynamic performance is pure moderate. Therefore, the control design procedure is essentially based on the partial reference model matching which offers a reasonable method to simplify the design and the controller configuration under the controlled system uncertainty. ITAE(Integral of time-multiplied absolute error) performance index and Kitamori method etc. which were used a reference model method had a limit to settling time and rising time of reference model that it arrived to steady state response according to the controlled system. On this study, if it only knew peak time of overshoot and settling time by measurement signal of the controlled system, it can be made the reference model easily. We proposed new method to improve performance index of the reference model superior to existing reference model index and illustrate the numerical simulation results to show the effectiveness of proposed control method design.

• Journal of Korea Society of Digital Industry and Information Management
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• v.18 no.2
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• pp.61-75
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• 2022

The purpose of this study is to analyze the impact of quality management system requirements, a management innovation technique, on business performance to secure the competitiveness of SMEs in an environment of increasing uncertainty in the global economy and intensifying competition. To this end, a survey was conducted on small and medium-sized enterprises (SMEs) operating a quality management system, and statistical analysis was performed through validity and reliability analysis, regression analysis, and group analysis using IBM SPSS 26.0. As a result of the study, it was found that planning, operation, support, and improvement, which are the core requirements of a quality management system, have a positive effect on business performance. In addition, through group analysis, it was found that the effect of quality management system requirements on business performance varies according to the level of the company. This means that the importance of quality management requirements required for strategy establishment varies according to the quality management introduction level of small and medium-sized manufacturers, and it can be used for small and medium-sized manufacturers to set strategic directions.

• Journal of the Korean Institute of Rural Architecture
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• v.20 no.1
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• pp.11-18
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• 2018

The study aims to address the energy crisis and realize self-sufficiency of building as part of local energy independence, breaking away from a single concentrated energy supply system. It is intended to develop modules of the outside insulation composite panels that conform to passive certification criteria and for site-assembly systematization. The method of study first identifies trends and passive house in literature and advanced research. Second, the target performance for development is set, and the structural material is selected and designed to simulate performance. Third, a test specimen of the passive outside insulation curtain wall module designed is manufactured and constructed to test its heat transmission coefficient, condensation performance and airtightness. Finally, analyze performance test results, and explore and propose ways to improve the estimation and improvement of incomplete causes to achieve the goal. The final test results achieved the target performance of condensation and airtightness, and the heat transmission coefficient was $0.16W/(m^2{\cdot}K)$, which is $0.01W/(m^2{\cdot})K$ below the performance target. As for the lack of performance, we saw a need for a complementary design to account for simulation errors. It also provided an opportunity to recognize that insulated walls with performance can impact performance at small break. Thus, to be commercialized into a product with the need for improvement in the design of the joint parts, a management system is needed to increase the precision in the fabrication process.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.3
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• pp.83-89
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• 2018

In the SW industry, the diversification of global markets and technology trends are changing due to the emergence of new services, and IT companies are in need of strategic change different from the previous one. In this study, SWOT analysis was performed by extracting the internal environmental factors and external environmental factors through the previous studies to improve the project performance competence of small IT companies, and the SWOT Matrix was reconstructed through the pairwise comparison. Based on this, the purpose of this research was to propose the project performance competency improvement plans for small IT companies based on importance and priority, and the following four strategies were derived from the result of SWOT-AHP analysis. SO strategy was drawn in direction to invest R & D in new SW industry to enhance technology competitiveness of SMEs in order to develop SMEs, and in order to secure competitiveness of SW industry, WO strategy is drawn the cultivation of professional technical manpower through SW policy. ST Strategy presented technical management through SW system improvement policy to improve SW environment, and WT Strategy presented awareness training on the construction and necessity of project management system construction. Using the strategies presented in this study, it is expected that the managers of small IT firms will be presented as references to measure the performance competence factors of current organizations and company organizations.

• KIEAE Journal
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• v.17 no.3
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• pp.51-58
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• 2017

Purpose: G-SEED's evaluation of existing buildings in Korea is an important point because the energy consumption and CO2 emissions of existing buildings are continuously increasing due to the aging of buildings over time. In 2016, the government has set up a 'Green Remodeling Certification Standard' in G-SEED in order to revitalize the green remodeling business of existing buildings. As a result, G-SEED is distinguished between buildings with green remodeling and buildings with general remodeling. Therefore, this study analyzed the system of the certification of the green remodeling building which is aimed at improving the performance of the building. Method: First, we analyze characteristics of the existing building certification standards of G-SEED(Korea), LEED(USA), and BREEAM(UK). Second, the evaluation criteria are based on the G-SEED Green Remodeling Certification, 2016, LEED for BD + C: New construction and major renovation v.4, BREEAM UK Non-Domestic Refurbishment and Fit-out 2014. Based on the analysis results, we propose the improvement direction of G-SEED Green Remodeling Certification Standard. Result: Existing buildings should be classified into 'existing building certification' for re-certification and 'green remodeling certification' accompanied by building performance improvement. In addition, building green buildings through performance improvement should include not only energy performance, but also creating a pleasant indoor environment and minimizing environmental impact. Finally, existing buildings have accumulated information on energy and resource use, and a performance improvement plan should be established based on this information.

• Journal of the Korean Society of Systems Engineering
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• v.20 no.spc1
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• pp.30-44
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• 2024

The DMAIC methodology, which is most familiar to battery production system developers, is partially inadequate in its conformity to utilize battery production system tasks, so it is necessary to improve the function and structure of the methodology, but many battery production system developers use the DMAIC method based on experience, causing side effects such as confusion, delay in tasks, and insufficient performance during tasks. Accordingly, we intend to conduct an empirical study to improve the "efficiency improvement and conformity evaluation method" so that the DMAIC methodology can be used more reasonably and easily. Using the three-stage research model, we derive components that affect conformity through literature and questionnaire surveys in the first stage, use relational characteristics between components in the second stage to confirm the effect on conformity, and use the relational characteristics in the third stage to confirm the possibility of improving efficiency by applying them to the DMAIC methodology in actual cases. Finally, the "Conformity Assessment Index (CAI) equation" based on relational characteristics is established to enable effective conformity evaluation and continuous improvement.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.1
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• pp.41-45
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• 1985

A degradation of the signal-to-noise ratio (SNR) in a digital moving target indicator system (DMTI System) can be Improved by weighting of the DMTI output pulses before the integration process. and it Is shown that the signal-to-noise ratio Is unproved as the nunlber of delay line cancellers. It is Known that signal-to-noise ratio obtained with optimum weighting is greater than that obtained with binomial weighting. An improvement performance of the signal-to-noise ratio for each case is presented through the results or a computter simulation.

• Journal of Communications and Networks
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• v.8 no.1
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• pp.13-20
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• 2006

In cellular mobile communications, how to achieve optimum system capacity with limited frequency spectrum is one of the main research issues. Many dynamic channel assignment (DCA) schemes have been proposed and studied to allocate the channels more efficiently, thus, the capacity of cellular systems is improved. Reuse partitioning (RP) is another technique to achieve higher capacity by reducing the overall reuse distance. In this paper, we present a network-based DCA scheme with the implementation of RP technique, namely dynamic reuse partitioning with interference information (DRP-WI). The scheme aims to minimize the effect of assigned channels on the availability of channels for use in the interfering cells and to reduce their overall reuse distances. The performance of DRP-WI is measured in terms of blocking probability and system capacity. Simulation results have confirmed the effectiveness of DRP-WI scheme. Under both uniform and non-uniform traffic distributions, DRP-WI exhibits outstanding performance in improving the system capacity. It can provide about 100% capacity improvement as compared to conventional fixed channel assignment scheme with 70 system channels.

• Journal of Korea Spatial Information System Society
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• v.8 no.1 s.16
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• pp.59-75
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• 2006

One of the most challenging and encouraging applications of state-of-the-art technology is the field of traffic control systems. It combines techniques from the areas of telecommunications and computer science to establish traffic information and various assistance services. The support of the system requires a moving objects database system (MODB) that stores moving objects efficiently and performs spatial or temporal queries with time conditions. In this paper, we propose schemes to distribute an index nodes of trajectory based on spatio-temporal proximity and the characteristics of moving objects. The scheme predicts the extendible MBB of nodes of index through the prediction of moving object, and creates a parallel trajectory index. The experimental evaluation shows that the proposed schemes give us the performance improvement by 15%. This result makes an improvement of performance by 50% per one disk.