• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.2
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• pp.230-235
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• 2008

Recently, LG chemical corporation developed new material called HYPERIER, which has an excellent barrier characteristic. It has many layers which are made of nano-composite within LDPE(Low-Density Poly Ethylene). In order to guarantee the quality of the final product from the production line, a certain test equipment is required to investigate the existence of layers inside the HYPERIER. In this work, ultrasonic sensor based test equipment for investigating the existence of inner layers is proposed. However, it is a tedious job for human operators to check the existence by just looking at the resounding waveform from ultrasonic sensor. Therefore, to enhance the performance of the ultrasonic test equipment, Fast Fourier Transform(FFT) and Principle Components Analysis(PCA) and Back-Propagation Neural Network(BPNN) are utilized which is used for classification of Quality. To verily the feasibility of the proposed scheme, some experiments are executed.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.1
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• pp.78-82
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• 2014

Power Transformers with more than one secondary winding are not uncommon in industrial applications. But new classes of applications where very large number of independent secondaries are used are becoming popular in controlled converters for medium and high voltage applications. Cascade H-bridge medium voltage drives and Pulse Step Modulation (PSM) based high voltage power supplies are such applications. Regulated high voltage power supplies (Fig. 1) with 35-100 kV, 5-10 MW output range with very fast dynamics (${\mu}S$ order) uses such transformers. Such power supplies are widely used in fusion research. Here series connection of isolated voltage sources with conventional switching semiconductor devices is achieved by large number of separate transformers or by single unit of multi-secondary transformer. Naturally, a transformer having numbers of secondary windings (~40) on single core is the preferred solution due to space and cost considerations. For design and simulation analysis of such a power supply, the model of a multi-secondary transformer poses special problem to any circuit analysis software as many simulation softwares provide transformer models with limited number (3-6) of secondary windings. Multi-Secondary transformer models with 3 different schemes are available. A comparison of test results from a practical Multi-secondary transformer with a simulation model using magnetic component is found to describe the behavior closer to observed test results. Earlier models assumed magnetising inductance in a linear loss less core model although in actual it is saturable core made-up of CRGO steel laminations. This article discusses a more detailed representation of flux coupled magnetic model with saturable core properties to simulate actual transformers very close to its observed parameters in test and actual usage.

• The Journal of Information Systems
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• v.29 no.1
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• pp.75-91
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• 2020

Purpose Retrofit, defined to be addition of new technologies or features to the old system to increase efficiency or to abate GHG emissions, is considered as an important alternative for the old coal-fired power plant. The purpose of this study is to propose mathematical method to model multiple alternative retrofit in Generation Capacity Expansion Planning(GCEP) problem, and to get insight to the retrofit patterns from realistic case studies. Design/methodology/approach This study made a multi-alternative retrofit GECP model by adopting some new variables and equations to the existing GECP model. Added variables and equations are to ensure the retrofit feature that the life time of retrofitted plant is the remaining life time of the old power plant. We formulated such that multiple retrofit alternatives are simultaneously compared and the best retrofit alternative can be selected. And we found that old approach to model retrofit has a problem that old plant with long remaining life time is retrofitted earlier than the one with short remaining life time, fixed the problem by some constraints with some binary variables. Therefore, the proposed model is formulated into a mixed binary programming problem, and coded and run using the GAMS/cplex. Findings According to the empirical analysis result, we found that approach to model the multiple alternative retrofit proposed in this study is comparing simultaneously multiple retrofit alternatives and select the best retrofit satisfying the retrofit features related to the life time. And we found that retrofit order problem is cleared. In addition, the model is expected to be very useful in evaluating and developing the national policies concerning coal-fired power plant retrofit.

• Journal of Korean Public Health Nursing
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• v.19 no.1
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• pp.129-138
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• 2005

As the patients who need to undergo liver transplant operation continues to grow. the number of livers that are donated can not keep pace with the demand. With the development of surgery skills, the necessity for operations from living donors is increasing. Nevertheless, satisfactory research has been conducted on the factors which generally affect the living donors. In this article. therefore. researchers focused on the factors which generally affect the donating liver donor in order to design a plan for recommending liver donation from living donors. The subjects were 91 living liver donors in C university hospital from October 1. 2000 to December 31. 2003. The results on the uncertainty of living donor, by test sheet. were analyzed with SAS program. The final results were as follows: 1. The uncertainty of the living donors was 51.54 marks per full credit 100. 2. The factor with the greatest effect on donation was the possibility of survival of the donor, followed by the admission period. marriage status and age. In recommending the living donation, the rate of donor survival after the operation was 5.2 times higher than death, 5.2 times higher when the admission period was under 20 days. 5.0 times higher when married. and 27.3 times higher when the family-related donation was very active at the age of 20s than in the 50s. These results suggest that all medical staffs should care for living donors with more interest and activity to give them the least complaints in admission and the lowest possibilities for complication. To enhance the survival rate and improve the surgical success rate. on-going monitoring should include regular health-checks. and continual efforts and education should be made to care for the health condition of the living donors after donation.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1049-1056
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• 2017

In this paper, a microstrip-fed dual-band monopole antenna with two arc-shaped lines for WLAN(: Wireless Local Area Networks) applications was designed, fabricated and measured. The proposed antenna is based on a microstrip-fed structure, and composed of two arc-shaped lines and then designed in order to get dual band characteristics. We used the simulator, Ansoft's High Frequency Structure Simulator(: HFSS) and carried out simulation about parameters L2, L5, and with/without slit to get the optimized parameters. The proposed antenna is made of $13.0{\times}34.0{\times}1.0 mm^3$ and is fabricated on the permittivity 4.4 FR-4 substrate($12.0{\times}34.0{\times}1.0mm^3$). The experiment results are shown that the proposed antenna obtained the -10 dB impedance bandwidth 360 MHz (2.29~2.65 GHz) and 1,245 MHz (4.705~5.95 GHz) covering the WLAN bands. Also, the measured gain and radiation patterns characteristics of the proposed antenna are presented at required dual-band(2.4 GHz band/5.0 GHz band), respectively.

• Korean Journal of Social Welfare
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• v.47
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• pp.272-309
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• 2001

It is a recent trend to emphasize community services for the rehabilitation of the mentally ill. However, it is also necessary to provide social work services for those living in the institutions, who is the most underprivileged in our society. To deal with interpersonal skill deficits which is one of the main characteristics of the mentally ill, social skills programs are being utilized, usually in the communities, but not in the institutions. Therefore, the objective of this study is to develop and evaluate institution-relevant program for the improvement of assertiveness, which is the basic ability among the interpersonal skills, and self-esteem, which is the emotional basis of assertiveness. Because there has been little literature on such a program, a preliminary program had been implemented in order to include the peculiarities of the life in the institutions on the main program. The evaluation of the program effect was done by pretest-post test control group design, and its results are as follows. Firstly, in regard to program effectiveness, the pre and post test showed that self-esteem improved in a statistically meaningful way, but that assertiveness did not so. However, the staff verified the improvement of the group members' assertiveness to some degree in their actual lives. Secondly, in regard to the group process, the group interaction improved in a statistically meaningful way between 2nd and 5th session, and the improvement maintained till the program termination. Also the group members evaluated the program as helpful in their everyday lives. Therefore it can be said that the result of this program is encouraging. In light of this, several suggestions were made: utilizing more dynamic techniques in the program; developing the advanced level of the program; making an effort to change environmental structures as well as individuals; applying this kind of program to another living facilities such as those for the homeless or handicapped.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.886-892
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• 2010

It is possible to use wireless communication any time in every place because of well-developed wireless networks and mobile devices. The AVL(Automatic Vehicle Location) system, therefore, has made practical use in situation control, distribution industry, home delivery service, and ITS(Intelligent Transportation System) area. In this paper, we design and implement an AVL system in order to use for fire fighting activities such as emergency rescue and relief. To do this, first, we investigate and analyze the existing researches and systems related to AVL system. In details, we develop an AVL server and clients to support stable communication each other using wireless networks. Using AVL system, calling cars find the position of accidents quickly and the fire defense headquarters control unforeseen accidents efficiently because the state of calling cars are confirmed in real time by their GPS data.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1837-1844
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• 2016

This paper proposes an antenna of the fork type structure that operates in the UWB (Ultra Wide Band) frequency band (3.1 ~ 10.6 GHz). The proposed antenna is attached a circular patch in order to obtain the UWB band characteristics to the fork-type patch antenna. The ground plane is implemented in a arc-shape configuration. The effect of various parameters of the modified fork type radiating patch and partial arc ground plane for UWB operation is investigated. The proposed antenna is made of $34.0{\times}50.0{\times}1.0mm^3$ and is fabricated on the permittivity 4.4 FR-4 substrate. The experiment results shown that the proposed antenna obtained the -10 dB impedance bandwidth 8200 MHz (2.7 ~ 10.9 GHz) covering the UWB bands. This result satisfied the characteristics of ultra-wideband and the proposed antenna will be applicable to an ultra wideband system.

• The KIPS Transactions:PartD
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• v.18D no.5
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• pp.403-414
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• 2011

Recently, smart phones based on Android platform have been widely used, and lots of applications have been developed. Data generated from an application are frequently transferred to other applications. Therefore, a method that can easily transfer or share meta-data among applications is required. Generally meta-data created by android applications are java objects. The android platform uses clipboard, intent and content provider in order to transfer data among the applications. However, those ways are designed to transfer data as a record. So these methods have to marshall the object to a record and unmarshall the record to an object. In this paper, we designed and implemented the MetaService which can transfer any type of object made by applications. When the MetaService is used, we can reduce complex implementations such as clipboards and content providers and we can reduce many bugs. Therefore, we can make the applications simple and increase productivity.

• Smart Structures and Systems
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• v.26 no.3
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• pp.331-343
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• 2020

In this paper, based on the CPT, motion equations for a sandwich plate containing a core and two integrated face-sheets have derived. The structure rests on the Visco-Pasternak foundation, which includes normal and shear modules. The piezo-magnetic core is made of CoFe₂O₄ and also is subjected to 3D magnetic potential. Two face sheets at top and bottom of the core are under electrical fields. Also, in order to obtain more accuracy, the effect of flexoelectricity has took into account at face sheets' relations in this work. Flexoelectricity is a property of all insulators whereby they polarize when subject to an inhomogeneous deformation. This property plays a crucial role in small-scale rather than macro scale. Employing CPT, Hamilton's principle, flexoelectricity considerations, the governing equations are derived and then solved analytically. By present work a detailed numerical study is obtained based on Piezoelectricity, Flexoelectricity and modified couple stress theories to indicate the significant effect of length scale parameter, shear correction factor, aspect and thickness ratios and boundary conditions on natural frequency of sandwich plates. Also, the figures show that there is an excellent agreement between present study and previous researches. These finding can be used for automotive industries, aircrafts, marine vessels and building industries.