• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.134-138
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• 2005

In this paper, we have developed a new type of the microwave phase conjugator for the active retrodirective antenna array. The circuit topology is consisted of a 2-port structure to avoid the complexity of LO and RF signal combination and matching, using the cascade connection of two single-ended mixers. The operating frequencies are 4.0 GHz, 2.01 GHz and 1.99 GHz for LO, RF, and IF, respectively. Conversion loss is measured to be -7 dB and 1-dB compression point 15 dBm with the LO power of 9 dBm. For the most important parameter, the isolation between RE leakage and IF signal is as high as 25 dB.

• Journal of the Korea Society of Computer and Information
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• v.17 no.9
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• pp.149-156
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• 2012

The Fabric Electrode was proposed for the effective production of the display based on electrowetting in this paper and designed the source driver of flexible display which could be driven by the electrowetting cell. The electrowetting cell matrix was implemented on the substrate(PET) by imprinting. The driver fabric, wetting electrode fabric and conductive fabric was placed horizontally and vertically in the groove between cell matrix and the electrowetting cell matrix can be driven by the cross-point as electric connection. The integration density of driver module is decreased because using the R/2R DAC module per channel in the conventional method. The proposed method could utilize the effective production process and reduce the production price of a display panel. The source driver which consume lower power and can increase the integration density because of reducing the number of driver device per channel was designed and evaluate the driver operation by the simulation using the VHDL programming in this paper.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.233-239
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• 2015

The demand of remote control and monitoring for efficiency and applications of LED streetlight is increasing continuously because the demand of LED streetlight was increase last few years. Existing street light remote control system is wired using a power line network. The wireless connection exists, but due to its low data transmission rate, it cannot support specialized applications. It can only support simple control and monitoring. In this paper, we propose a system that uses a IEEE 802.11s wireless mesh network based on WLAN, as a backbone network for remote control and monitoring of the LED street lights along with other specialized applications. Using the wireless mesh network for remote control and monitoring the LED street lights, the same can be used to act like a public Wi-Fi access point. We have designed Wi-Fi integrated LED streetlight controller and implemented our system. We evaluated the performance of our system on a real test bed. Our proposed system is expected to perform the role of a U-city infrastructure by utilizing the wireless mesh network.

• Journal of the Korean Society of Safety
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• v.26 no.4
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• pp.41-46
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• 2011

The purpose of this paper is to analyze the causes of accidents related to the 3 phase 170 kV gas insulated switchgear of a power system collected from accident sites to secure data for the prevention of similar accidents and provide important points of view regarding diagnosis for the prevention of accidents involving gas insulated switchgears. The analysis results of the causes of accidents involving gas insulated switchgears showed deformation of the manipulation lever installed at the S-phase, disconnection of the insulation rod connection, melting of the upper conductor, a damaged tulip, damage to the lower spacer and the spacer at the breaker, etc. It is believed from this result that the potential for accidents has expanded due to accumulated energy as a result of repeated deterioration. The carbonization depth of a GIS was formed near the screw (T2, T3) used to secure the lower pole of the S-phase tulip. It is not known what has caused the screws to be extruded and melted. However, it is thought that an unbalanced electromagnetic force, micro-discharge, surface discharge, etc., have occurred at that point. In addition, even though 16 years have passed since its installation, there was no installation defect, act of arson, accidental fire, etc. General periodical inspection and diagnosis failed to find the factors causing the accidents. As a system contained in a closed metal container, it has a high risk factor. Therefore, it is necessary to design, install and operate a GIS in accordance with the standard operational procedure (SOP). In addition, it is necessary to apply conversion technology for periodical SF6 gas analysis and precision safety diagnosis. It is expected that tracking and managing these changes in characteristics by recording the results on the history card will provide a significant accident prevention effect.

• Fire Science and Engineering
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• v.31 no.5
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• pp.70-77
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• 2017

As the quality of live gets better, the frequency of using air conditioner is along drastically increasing. On that matter, setting up measures of preventing increasing fire cases has been required. 43,413 fire cases occurred in last 2016, the cases occurred by electricity account for about 20%(8,655 cases). Among the electricity cases, the amount of cases occurred with air conditioner issues covers 1.5%; causes of the fire incidents vary, including incomplete contacts, short circuits, tracking, and such. In this study, we intend to investigate the case of ignition at the connection point where the power cord connected to the outdoor unit is arbitrarily connected during the air conditioner installation process, and to propose preventive measures against the cause in order to reduce the damage of life as well as the property from electric fire incidents.

• Korean Security Journal
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• no.59
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• pp.189-215
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• 2019

As modern society has become specialised and complex in all areas of politics, economy and society, it has reached a point where it is difficult to control crime with the general public power. Private security, which began to fluctuate after the 19th century, has expanded its scope to subsidise public power in various areas, sometimes beyond public power. Among these private security activities, the private investigate system has long been used to provide private investigate services that are safe from personal human rights protection and crimes. This study investigate the private investigation system in the United Kingdom and South Korea focusing on the missing person investigation system by using the qualitative content analysis of research methods. First, the results of the qualitative content analysis are described through methods such as literature reviews and interviews on how the British private investigation system and the missing persons search system are implemented. Next, the results of the content analysis are presented through the methods of literature reviews and questionnaires on how the implementation of the civilian survey in Korea and the search for missing people is proceeding. It is a very important field in both countries, and there is a very limited study, especially from a Korean perspective. Therefore, it is expected that this study will not only facilitate discussions for the successful legalisation of the private research system, but also provides a basic foundation for future research. The study of the private research system should be ongoing and periodic, not temporary. In addition, in order to introduce Korea's private survey system, the private investigation system should be developed by discovering the problems of the Private Investigation Law mentioned in this study and collecting opinions from citizens, academics and related institutions. The introduction of the private investigation system requires the connection of the efforts and interests of citizens, academia and related institutions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2968-2974
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• 2010

Nowadays, the PV systems have been focused on the grid connection between the power source and the grid. The PV inverter can be considered as the core of the whole system because of an important role in the grid-interfacing operation. An important issue in the inverter control is the load current regulation. In the literature, Proportional Integral (PI) controller, which is normally used in the current-controlled Voltage Source Inverter (VSI), cannot be a satisfactory controller for an AC system because of the steady-sate error and the poor disturbance rejection, especially in high-frequency range. Compared with conventional PI controller, Proportional Resonant (PR) controller can introduce an infinite gain at the fundamental frequency of the AC source; hence it can achieve the zero steady-state error without requiring the complex transformation and the de-coupling technique. Theoretical analyses of both PI and PR controller are presented and verified by simulation and experiment. Both controller are implemented in a 32-bit fixed-point TMS320F2812 DSP processor and evaluated on a 3kW experimental prototype PV Power Conditioning System (PCS). Simulation and experimental results are shown to verify the controller performances.

• Journal of the Korean Society of Costume
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• v.18
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• pp.291-306
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• 1992

From the mid-1980s '91s, remarkable Ethnicism and Primitivism in the Europe fashion trend could be represented as an exotic taste longing for secenery and emotion of non-europe area in the West. These phenomenon could be found out in connection with Acculturation, which means when two different cultures or more were contacted they were identified or merged in process of diffusion and change of them. This point of view was the culture anthropologic one that make a comparison and analysis of sameness and difference between cultures. The purpose of this study was to illuminate exotic taste represented in costume in the cluture-anthroplogic aspect, to compare with beauty of costume that each culture of costume and the meaning of the times due to those differences. an aspect of the exotic taste and character in the western costume that was inspected by dividing into 'Primitivism', 'Oriental element' and 'the element of a national costume in the East European bloc ' were as follows; First, Primitivism had something in common with what was pursued in the trend of Modern Art, through the late 19th century to the early 20th century. In fashion fettered by technique, the creation expressed in a free was and showed simple beauty of costume. At the same time, pure emotion expression, creative power and witty strong expression give the cognition of transcendency breaking the routine and the cognition of complexity of an included conception. Those are garments showing not only the primitive thought and mysticism but a fancy, an abstraction, and a life. Colors and accessaries which described nature and matched simple costume composition to the expression of various material or patterns transmitted the image of the primitive strongly. Second, "Drental element" which had an effect on western custome historically in a long time had outstanding luxurios adornmental beauty of custome. Extending from the Arab stated India, China, Korea, Japan, each national costume with a gay national culture became one of motif. Various ornamental factors expressed on Trapez Line, Sime Line and Drape, or Raied style, which did not restrict the body. Those were not only functional Easy Look, but were also satisfying human's ornamental desire. Third, national factors in the East European bloc are theme that begins to be embossed in the late 80's. In view of a political change and cultural situation with a double character of Europe and Orient, it was estimated that national factors have great importance in fashion. Item concerned with new concern appeared at Autumn & Winter collection. It shows elegant and graceful beauty of costume by adding a fur or jewel to simple form. These national factors in the East European bloc are simple form, but shows the difference in more cubic formation than form expressed in Primitivism or Oriental factors Exotic taste appeared form 80's to 91's, is thought to create an forgotten romantic emotion and traditional fashion

• Korean Journal of Social Welfare
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• v.62 no.1
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• pp.237-261
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• 2010

This study aims at exploring the employment experiences of people with psychiatric disabilities who look for job and work at workplace through deeply searching that of people with psychiatric disabilities from the point of their view. So this research shows how their employment experiences appears in our country and also what kind of meaning that gives to people with psychiatric disabilities. The Main question of this study is what the meaning and essence of employment experiences of people with psychiatric disabilities is. The qualitative research method was taken for widely understanding and lively writing employment experiences of people with psychiatric disabilities in the connection of their lives. Especially, it was set that phenomenological research methods introduced by Colaizzi's, which can be used for understanding the essential meaning of the experiences of research participants. The major themes could be analyzed as "Entering a narrow door", "Being raised on an unfamiliar stage", "Confusing in the fast world", "Enduring", "Adjusting to an ordinary life", and "Taking a step forward admitting their limitation". These are connected not in the state of independence state but dependence according to time flow. In this study the people with psychiatric disabilities in relation to employment are compared to salmons running back in a wild river. People with psychiatric disabilities have power through running back in their employment and lives like a long river. Even though there are difficulty things, they actively try to flow together with other people as mature people in our society. This research helps to make strategies of employment supports for people with psychiatric disabilities through their employment experiences.

• Journal of Sensor Science and Technology
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• v.14 no.2
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• pp.69-77
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• 2005

The electronic nose (e-nose) has been used in food industry and quality controls in plastic packaging. Recently it finds its applications in medical diagnosis, specifically on detection of diabetes, pulmonary or gastrointestinal problem, or infections by examining odors in the breath or tissues with its odor characterizing ability. Moreover, the use of portable e-nose enables the on-site measurements and analysis of vapors without extra gas-sampling units. This is expected to widen the application of the e-nose in various fields including point-of-care-test or e-health. In this study, a PDA-based portable e-nose was developed using micro-machined gas sensor array and miniaturized electronic interfaces. The rich capacities of the PDA in its computing power and various interfaces are expected to provide the rapid and application specific development of the diagnostic devices, and easy connection to other facilities through information technology (IT) infra. For performance verification of the developed portable e-nose system, Six different vapors were measured using the system. Seven different carbon-black polymer composites were used for the sensor array. The results showed the reproducibility of the measured data and the distinguishable patterns between the vapor species. Additionally, the application of two typical pattern recognition algorithms verified the possibility of the automatic vapor recognition from the portable measurements. These validated the portable e-nose based on PDA developed in this study.