• Journal of Korean Neurosurgical Society
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• 제40권4호
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• pp.300-303
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• 2006

The authority and reputation of a medical journal is based on the number of received citations. Korean Medical Citation Index [KoMCI] provides information about citations of Korean medical journals since 2002. All six issues of KoMCI [from 2000 to 2005] were used for analysis. Citations, impact factor, and their changes were evaluated. We compared the data of Journal of Korean Neurosurgical Society[JKNS] with other Korean medical journals. The impact factor[IF] of 2005 maintained increased value since 2004, although the impact factor excluding self citation[ZIF] returned previous low value. Improvement in proportion of Korean citations and in proportions of non-self received citations were encouraging changes. Although there were some improvements, the status of JKNS with respect to ZIF is still behind other Korean medical journals selected for comparison. Improvement of the status of JKNS by aid of KoMCI and enhanced reputation of KoMCI by its positive influence on JKNS or other Korean medical journals will be beneficial to members and medical societies of Korea.

• Journal of Electrical Engineering and Technology
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• 제5권3호
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• pp.468-476
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• 2010

This paper presents a direct single-stage power converter using single-phase isolated full-bridge converter modules, with inherent power factor correction (PFC) for a 12 kW switched mode power supply (SMPS). The advantages of the proposed converter are its simple control strategy, reduction in number of conversion stage, low input line current harmonics, and improvement in power factor. Analysis of the single-stage converter is carried out in continuous conduction mode of operation. Steady-state analysis of the proposed converter is conducted to obtain converter parameters. A systematic design procedure is also presented for a 12k W converter with a design example. The effect of load variation on SMPS is also studied in order to demonstrate the effectiveness of the proposed converter for the complete range of load conditions. A set of power quality indices on input ac mains for an SMPS fed from a single-stage converter is also presented for easy comparison of their performance.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• 제64권
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• pp.187-210
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• 2014

As port functions change to act as an economic catalyst and take on a central position in industries engaged in international trade, port hinterland has become a significant component in international shipping. The success of port hinterland as a strategic base of logistic activities critically depends on location selection factor for international distribution center that links elements of global supply chain management. By examining multi-measurement items empirically, this paper analyzed location selection factor for international logistics distribution center in port hinterland, and evaluated Busan new port hinterland from the user's perspective. Employing exploratory factor analysis, the results revealed that the model structured around five factors incorporating geo-location and accessibility, availability, political supports, cost factors, and quality of business environment is valid and reliable in the context of the location selection factors for logistics distribution center in the context of port hinterland operations. The evaluation of Busan new port hinterland provides useful insights for strategic improvement to accommodate the users' expectation. Further, the model offers both a descriptive and diagnostic strategic management tool for port hinterland development and operations, to guide future improvement.

• The Korean journal of helicobacter and upper gastrointestinal research
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• 제18권3호
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• pp.186-197
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• 2018

Background/Aims: To investigate the predictive factors for improvement of atrophic gastritis (AG) and intestinal metaplasia (IM). Materials and Methods: A total of 778 subjects were prospectively enrolled and followed up for 10 years. Histological analysis of AG and IM was performed by using the updated Sydney system. To find the predictive factors for reversibility of AG and IM, 24 factors including genetic polymorphisms and bacterial and environmental factors were analyzed. Results: In all subjects, the predictive factor by multivariate analysis for improvement of both antral and corpus AG was successful eradication. The predictive factors for improvement of antral IM were age and successful eradication. The predictive factor for improvement of corpus IM was successful eradication. In patients with Helicobacter pylori infection, age and cagA were predictive factors for improvement of AG and IM. In patients with H. pylori eradication, monthly income and cagA were predictive factors for improvement of AG and IM. Conclusions: H. pylori eradication is an important predictive factor of regression of AG and IM and would be beneficial for the prevention of intestinal-type gastric cancer. Young age, high income, and cagA are additional predictive factors for improving AG and IM status. Thus, various factors affect the improvement of AG and IM.

• Journal of the Korean Solar Energy Society
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• 제23권3호
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• pp.45-53
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• 2003

This paper presents a study on the power factor improvement of V47- 660 [kW] Wind Turbine Generation System (WTGS) in Jeju wind farm, as a model system in this paper. In this system, the power factor correction is controlled by the conventional method with power condensor banks. Also, this system has only four bank steps, and each one capacitor bank step is cut in every one second when the generator has been cut in. This means that it is difficult to compensate the reactive power exactly according to the variation of them. Actually, model system has very low power factor in the area of low wind speed, which is almost from 4 to 6 [m/s]. This is caused by the power factor correction using power condenser bank. To improve the power factor in the area of low wind speed, we used the static var compensator(SVC) using current controlled PWM power converter using IGBT switching device. Finally, to verify the proposed method, the results of computer simulation using Psim program are presented to support the discussions.

• Journal of Digital Convergence
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• 제15권9호
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• pp.23-33
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• 2017

Given the expansion of globalization and international trade, the number of apparel consumers is growing every year, making it difficult to estimate the amount of handling needed from the logistics industry. To determine which management factors are important and which ones require improvement, fuzzy AHP was used. Using this method, the factors were ranked in the final analysis as follows: The first and most important factor was training employees (0.17), while the second was fire hazard management (0.169); the third-highest factor was inbound and outbound goods (0.142), and the fourth was the warehouse management system. Barcode management was ranked fifth. By these results, we were able to analyze the processes of clothing warehouses, noting that although the factors appear independent, they are actually connected while proceeding with full management control. Moreover, because of the special characteristics of garments, employee management is crucial. Due to the vulnerability of these goods to fire hazards, this factor must be well managed.

• The Transactions of the Korean Institute of Power Electronics
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• 제6권5호
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• pp.410-415
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• 2001

This paper proposes a new control scheme for the power factor improvement of DC power regenerating systems, which can regenerate the excessive DC power from DC bus line to AC supply in substations for traction systems. From the viewpoint of both power capacity and switching losses, the system is designed on the basis of three-phase square-wave inverters and composed of two inverters, zig-zag connected output transformers, and an AC filter. The output voltages of the regenerating system are not sinusoidal. However, regenerated complex power is analyzed on the basis of fundamental components and thus the reactive power produced by harmonics is not considered. Therefore, it is needed a new control scheme capable of controlling the reactive power nearly to zero even for nonsinusoidal cases. To verify the validity of the proposed control scheme, computer simulations are carried out. And the results show that the power factor is theoretically higher than 0.99.

• The Transactions of the Korean Institute of Electrical Engineers A
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• 제48권12호
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• pp.1507-1513
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• 1999

This paper describes simulation and experimental results to analyze the dynamic characteristics of STATCOM, which is connected to the ac system for compensation the power factor and improving the voltage stability. The simulation and experimental results confirm that the scaled model for STATCOM can properly compesate the power factor of the load and regulate the bus voltage at the common connection point.

• Proceedings of the KIPE Conference
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.384-387
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• 2000

In this paper Power factor correction circuit of single-phase three-level boost converter is proposed. The advantage of the proposed control scheme for three-level boost converter are low blocking voltage of each power device low THD(Total Harmonic Distortion) and high power factor. The control scheme is based on the current comparator capacitor compensator and region detector, In simulations the proposed system is validated.

• Proceedings of the KIEE Conference
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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• pp.94-96
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• 1993

At an operating point of the induction motor, there are many sets of stator frequency and voltage. This paper presents an algorithm to determine the stator frequency and voltage which maximizes the power factor without any informations of motor parameters. Improvement of efficiency us also expected due to high-power-factor operation.