• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.8
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• pp.1367-1372
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• 2007

The modem large electric power system has made power system analysis much more complex and difficult. For effective analysis of the power system, model reduction and aggregation is required. In this paper, a new relation index to identify the coherency among the generators is presented and also a new aggregation method is presented to aggregate the coherent generators in the large scale power system while matching the power flow. In order to demonstrate the effects of this aggregation method, it is applied to the IEEE 39 bus test power system and to the 2006 summer power system of Korea Electric Power Corporation, and the simulation results are compared with those of the original system.

• Journal of ILASS-Korea
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• v.24 no.3
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• pp.122-129
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• 2019

Flow uniformity in aftertreatment system is an important factor in determining uniform catalytic reaction and filtration. In this study, variety types of DOC-DPF system design were analyzed to increase flow uniformity. For this analysis, ANSYS Fluent was used with porous media setup for DOC and DPF. Turbulent flow was modeled by standard $k-{\varepsilon}$ model excepting porous media. Uniformity index was utilized to evaluate the flow uniformity quantitatively. Reference design showed low velocity region because two large vortex were generated before baffle. When radius of DOC-DPF system was increased, exhaust pressure acting on the inlet decreases and velocity distribution was shifted to one side. When inlet pipe was set to axial center of DOC-DPF system velocity distribution was symmetric. However, flow was not dissipated until the front end of DOC and showed higher uniformity index. When the volume of DOC was reduced while fixed volume of entire DOC-DPF system and baffle plate is located downstream of the DOC-DPF system, there was improvement in uniformity index.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.32
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• pp.281-296
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• 1994

In this paper, a new index(joint index) which shows the higher confidence than that of the existing technical indices and has simple logical structure and an index which is an applied form of the existing index(OBV-I index) are proposed. The index characteristics which have been known are verified by choosing the three most used technical indices(ADR index, investment psychological rate and VR index) as samples. And the index characteristics of the joint index are compared to those of the OBV-I index. The comparisons are executed not by comparing the investment earning rate of each index but by calculating the unnecessary number of trade days in the total number of trade days according to the index.

• Journal of the Korea Safety Management & Science
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• v.19 no.1
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• pp.219-226
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• 2017

This study investigates application cases of facility management system model for enhancing facility productivity of industry filed around medium and small facility processing companies and finds the inefficiency of the existing management model. Following items are researched to seek out methods and measures to maximize facility productivity through empirical analysis by exploring and establishing a new management model. First, the empirical analysis, it is found that the overall equipment efficiency index used for facility productivity management in the companies has a difficulty being used as the index for it in actual medium-small processing companies. Second, a new facility management system model applying standard cycle time is suggested among facility management index system to measure facility productivity. Third, the empirical analysis is used to verify that developed facility management system model is a useful method to manage the facility productivity by applying the model to actual medium-small processing companies. Finally, it is necessary to implement comparison analysis on whether actual productivity enhancement induces a distinctly different result by using a new facility management index system model to be inhibited in this study.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.7
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• pp.515-522
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• 2018

An orthogonal frequency division multiplexing with coded direct index modulation(OFDM-CDIM) system that can achieve higher performance and spectral efficiency than previous OFDM systems is proposed. Previous OFDM with index modulation(IM) and OFDM-IM using dual modes systems allocate additional data to indices of respective subcarriers through combining operation with high complexity and then transmit them. However, the proposed system directly allocates the mode selection information to each subcarrier without performing additional operations. Then, the system selects and transmits one symbol in the selected mode. Furthermore, only the data allocated to the index of the subcarrier is encoded, and a good performance improvement effect is obtained with a high code rate. Simulation results show quantitatively that an OFDM-CDIM system using four modes improves bit error rate performance and transmission efficiency in additive white Gaussian noise and Rayleigh fading channel environments compared with a conventional OFDM system using 4-ary quadrature amplitude modulation.

• The Journal of Korean Physical Therapy
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• v.30 no.5
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• pp.193-198
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• 2018

Purpose: The purpose of this study was to analysis of effectiveness between cognitive function assessment scores and gaming cognitive rehabilitation system in children with intellectual impairment. Methods: Five children (male=5, $age=10.00{\pm}0.80$) with intellectual impairment participated in this study and were randomly assigned to the experiment that played (received) gaming cognitive rehabilitation system (Neuroworld). The children were applied 2 times a week for 30 minutes during 3 months. The children were assessed K-WSIC-VI (Korean-Wechsler intelligence scale for children-fourth edition) and recorded that gained score in gaming cognitive rehabilitation system before and after intervention. K-WSIC-VI contained five primary index scores: verbal comprehension index, visual spatial index, fluid reasoning index, working memory index, and processing speed index. Gaming cognitive rehabilitation system scoring was composed visual recall, target recall, sequence recall, selective attention, continuous attention, and exploration. Results: In the intelligence quotient (IQ) of K-WSIC-VI, there were significant increased in all children. The visual recall item was highest effective in all children. However, sequential recall showed the lowest improvement in all children. The performance speed of selective attention item was decreased, this means that children's skills have improved. Also, their ability to explore has improved significantly. Conclusion: In conclusion, gaming cognitive rehabilitation system was significant effectiveness in cognitive function in some categories for children with intellectual impairment. However, the visual recall and performance speed don't represent of all cognitive function. Therefore, further studies will need to verify by applying more subject and longer duration.

• Journal of Navigation and Port Research
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• v.40 no.3
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• pp.147-157
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• 2016

The trend of globalization and the development of the communication-Information technology have led the organization of a complex supply chains which are more vulnerable to risks. The impact of risk on the supply chain can be adverse so importance of risk management on a supply chain has increased. In order to analyze the risk factors of transport system, this study described about the definition of transport risk and investigated the relationship between likelihood index and effect index of each risk factor. We identified risk factors on transport system and measured likelihood index and effect index of each risk factor. Finally, a numerical risk index, which is a value of total transport system, has been resulted by aggregating all indices. In addition, a case study using the proposed method has done on a heavy vehicle transport context with a transport company.

• Bulletin of the Korean Mathematical Society
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• v.48 no.1
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• pp.35-50
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• 2011

We construct the index pairs of an isolated neighborhood for a dispersive dynamical system and investigate the existence of an index pair which is stable under small perturbations of the dispersive dynamical systems.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.5
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• pp.1108-1118
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• 2014

The purpose of this study was to spread the education of human creativity program and its possibility of consistency, and its application to school system by exploring the evaluation system that determines the valuable and useful decisions. This study was based on the evaluation system according to CIPP model regarding the program's general ideas and its role. The interest of the education of human creativity was increasing as well as its progress of program, and we searched 13 figures and 55 evaluation index according to increase the program's effectiveness and nation-wise situation of evaluation model. The conclusion of this study was that the human creativity program's evaluation was composed of six compartments. And the context evaluation was composed of three evaluation models and eleven index, and input evaluation was composed of three evaluation model and 15 index, while process evaluation is composed of three evaluation models and thirteen evaluation index. Lastly, output evaluation had four evaluation model and sixteen index.

• Journal of Drive and Control
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• v.19 no.4
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• pp.29-35
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• 2022

In this paper, we developed a workload index for monitoring the durability test using operation information of an excavator. First, the acceleration and cylinder pressure were selected as load factors by analyzing operation data. Through load correlation analysis according to each load factor, Root Mean Square (RMS) and Work Load Range (WLR) were respectively derived as a load feature representing mechanical load. In addition, the workload index was used to quantify load features. For applying the workload index to monitoring, a real-time monitoring system consisting of sensors and embedded controller was installed on the excavator and the system was integrated with a remote monitoring environment using a wireless network. Results of load monitoring and analysis verified that the developed workload index was effective from the viewpoint of the relative comparison of the workload.