• Proceedings of the Acoustical Society of Korea Conference
• /
• spring
• /
• pp.237-240
• /
• 2000

본 연구에서는 한국 동해 대륙붕 해역에서의 주요 해양현상인 수직 수온구조의 단기변동, 수온전선, 그리고 내부파의 변동을 분석하고 이들 변화에 따른 음파의 음장변화를 고찰하였다. 한국 동해항 근해에서 수온의 수직적 변화는 계절적인 변화 이외에 약 2주간의 짧은 기간에도 매우 극적인 변화가 존재함이 실측자료를 통해 밝혀졌다. 1999년 관측된 CTD 자료를 바탕으로 음장 변화를 살펴본 결과 주파수 1kHz, 음원수심 $30{\cal}m$ 인 경우 수신기 수심에 따라 최소 3dB, 최대 10dB까지 차이를 가져올 수 있음을 알 수 있었다. 한국 동해에서 연안과 외해 사이에는 수온전선이 매우 자주 발달하며 여름에 가장 강한 것으로 알려져 있다. 동해항 근해에는 대표적인 수괴인 대마난류수와 북한한류수가 공존하며 이들의 상대적인 세력 변화 때문에 수은(음속)이 거리에 따라 급격하게 변하는 수온전선이 발달할 수 있다. 저주파수 대역 (200Hz)에 대한 간단한 시뮬레이션 결과는 수온전선이 정상적인 분포에 비해서 거리에 따라 7dB 정도의 큰 전파손실을 초래할 수 있음을 보인다. 한국 동해 연안에도 내부파가 존재한다는 사실이 최근 3년간의 연구 결과 밝혀졌다. 내부파는 외해에서 발생하여 대륙단을 거쳐 대륙붕으로 진행해 오면서 내부파 군 (Packets)으로 분산된다. 수직적 변화가 전체 수층의 $14\%$를 차지하는 간단한 형태의 내부파를 가정하여 음장변화를 시물레이션 한 결과 주파수 1 kHz, 음원수심 $20{\cal}m$인 경우 내부파는 수렴구역 형성을 현저하게 방해하여 최대 5dB까지의 차이를 유발하였다. 추후 이에 대한 연구는 내부파 전체의 시,공간적 분포 특성이 구체적으로 규명되면 보다 정확한 음장변화 추정이 이뤄져야 할 것으로 보인다. 또한 내부파와 음파의 상대적인 진행 방향에 따라 음장변화가 크게 다를 것이 예상되므로 이를 규명하기 위해서는 궁극적으로 3차원적인 음장분포 연구가 필요하다. 음향센서를 해저면에 매설할 경우 수충의 수온변화와 센서 주변의 수온변화 사이에는 어느 정도의 시간지연이 존재하게 되므로 이에 대한 영향을 규명하는 것도 센서의 성능예측을 위해서 필요하리라 사료된다.

• Journal of the Economic Geographical Society of Korea
• /
• v.19 no.3
• /
• pp.550-565
• /
• 2016

The size of Korean and global cosmetic industry market are consistently growing and the domestic cosmetic industry's rate of total production increase is higher than GDP in Korea. In addition, the Korean Wave has strengthened not only this phenomenon but also the increase of exports. For these reasons, the purpose of this paper is to analyze Korean cosmetic industry regarded as a new growth engine. For this study, Porter's Value Chain theory, Mudambi's Smile of Value Creation, Cosmetic GMP by ISO, and the production process on cosmetic industry are used as tools. As a result, Korean cosmetic industry comprises five nodes value chains: R&D, Raw Material Manufacture, Container Manufacture, Cosmetic Manufacture, and Marketing. And then, based on this result, the spatial analysis is conducted to identify spatial distribution characteristics of each node.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.294_295
• /
• 2009

Superconducting fault current limiter (SFCL) is an power device of a novel concept. While SFCLs generate no ohmic loss during the operation carrying normal currents, they can limit fault currents very fast making large impedance by their quench characteristics. In 2006, KEPCO has developed a distribution class hybrid type SFCL by a collaborative research project with LS industrial systems. The SFCL has merits in practical and economical points of view. In the SFCL, the superconductor just plays a role of a fault detector and the current limiting is completed by the other current limiting element made of normal metals throu호 the line commutation. As a result, the required amounts of superconductors can be reduced considerably. Consequently, the hybrid SFCL can be fabricated with small size and cost, maintaining perfect current limiting performance. Currently, KEPCO is carrying out a research project at Gochang power test center for the purpose of the verification test of the 22.9 kV/ 630 A class SFCL for the practical application in real grid. Through the project, a long term operational test and fault current test will be done. In this paper, the back ground of development and installation of the SFCL will be explained and the operation plan of the SFCL for the verification test is also introduced.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.9
• /
• pp.1313-1317
• /
• 2013

With increasing demand of power, the equipment of power system is enlarging and the absolute capacity is going up. As a result, when a fault occurs, the fault current is consistently increasing. Therefore, I suggested some solution for limiting the fault current more efficiently. This study shows the characteristics of superconducting limiting elements and normal conducting elements combined with a transformer. We performed a short-circuit test about the fault current by using SCR switching control system operated from a CT. When short circuit accidents happened in the secondary side of a transformer, fault currents flowed and a SCR switching control system was operated. It resulted in a decrease of the fault current in the limited elements of third winding connected in parallel. For this test, we used YBCO thin films and normal conducting elements as the limited elements. Within a cycle, a superconducting fault current limiter with YBCO thin films reduced more than 90% of fault current because the resistance of superconducting elements sustainedly grew. On the other hand, the limiter with normal conductors limited as much as a set value because its resistance characteristic was linear. Consequently, in case of the limiter with superconductor, limiting range of the circuit was wide but the range of protective detection was undefined. In contrast, as for the limiter with normal conductors, limiting range and protection duty were appropriate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.30 no.2
• /
• pp.106-110
• /
• 2017

This paper compared current limiting characteristics of superconducting fault current limiter (SFCL) using E-I core due to the location of windings. Since E-I core has three legs and two magnetic paths, the current limiting characteristics of SFCL were expected to be affected by the installation location of windings, either center leg or right/left leg. To analyze its characteristics, the electrical equivalent circuit of the SFCL were derived and the electromagnetic analysis for the SFCL with the designed structure were performed. From the short-circuit tests, the hysteresis curve and the voltage-current trajectory of the SFCL due to the installation location of windings were extracted and compared each other. The SFCL with windings in the center leg of E-I core was shown to be larger magnetizing inductance compared to the one with windings in the right or left leg of E-I, which was analyzed from the hysteresis curve. In addition, larger decreased fault current right after the fault occurrence in the SFCL with windings in the center leg of E-I core was confirmed than the SFCL with windings in the right or left leg of E-I.

• The Korean Journal of Food And Nutrition
• /
• v.30 no.3
• /
• pp.440-453
• /
• 2017

In this study, we conducted an empirical analysis using structural equation modeling (SEM) by distributing questionnaires to 208 Chinese tourists who constitute the largest proportion of foreign tourists visiting South Korea. The survey was conducted in a face to face (FTF) manner with the aim to contribute to globalization of Korean cuisine through comprehensive analysis of the effects of preference characteristics of Korean wave dramas on the relationship among images, attitudes, and purchase intentions for Korean cuisine. The main actor characteristics among the preference characteristics of Korean wave dramas had a significant effect on the attitudes and purchase intentions for Korean cuisine. However, the thematic characteristics among the preference characteristics of Korean wave dramas did not have a significant effect on the purchase intentions for Korean cuisine; in addition, the production characteristics did not have a significant effect on the attitudes and purchase intentions for Korean cuisine. The eco-friendly and health images of Korean cuisine had a significant effect on the purchase intentions for Korean cuisine, and the attitudes toward Korean cuisine significantly affected the purchase intentions for Korean cuisine. Based on the results of this study, it is considered necessary to continuously publicize Korean cuisine through Korean wave dramas to build positive attitudes toward Korean cuisine through enhanced images of Korean cuisine.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.28 no.8
• /
• pp.40-46
• /
• 2014

The development of the superconducting fault current limiter (SFCL) to apply into a power transmission system where makes larger fault current compared to the power distribution system has been performed. Among various SFCLs, the trigger-type SFCL is suitable for application into the power transmission system due to the effective reduction on power burden of the high temperature superconducting element (HTSC) for the larger fault current. To protect the power transmission line in the power grid, the distance relay, which decides to interrupt fault section where can be calculated by the measured voltage and current from sound grid, is one of important protective devices in the power transmission system. However, the operation of the distance relay from the impedance of the fault point on the transmission line is affected by the impedance of the trigger-type SFCL. Therefore, the analysis on the operational characteristics of distance relay considering the application of the SFCL is required. In this paper, the effect on the operation zones of the distance relay by the impedance of the SFCL in a power transmission system was analyzed through the PSCAD/EMTDC simulation.

• Journal of Korea Game Society
• /
• v.8 no.3
• /
• pp.15-22
• /
• 2008

Recently, Our average life span of korean people is extended and fast-growing an elderly population caused by Being Improved our living conditions and medical science level. Our another problems which being faced by an aging population are that marked psychological and social changes of the aged. The psychological changes of the aged is related to how they make their living and it strong influences on their successful aging process. For health of the aged, there is an urgent need of recreation which can be social activities to void decline their own process of thinking and the executive ability to adapt for controlling health. Therefore, thepurpose of this recreation Courseware program is to help the alienated minorities to achieve the optimal health and best quality of life based on the knowledge of the social-activities and to understand the korean traditional culture plays. Finally, This study could contribute it as a baseline model for the empirical study and to develop further recreation program for the elderly social activities and sufficient for needs of understanding our traditional culture plays.

• Journal of Digital Contents Society
• /
• v.11 no.1
• /
• pp.47-55
• /
• 2010

Cultural Content Industry, a core industry based on knowledge, is becoming an economic model making new benefits by adding human creativity, imagination, sensitivity and style in to information technology. Cultural Contents Industry representing cultures of each countries is facing major changes towards a new competitive industry of each nation. Cultural content of a country is upbringing new contents power developing into a new industry by flattening the barriers within nations. But cooperations face difficulties in launching the industry because of limited information about the current market and lack of understanding in cultural differences. In order to solve this problem, this paper aims to create global network leading to increase of export and creation of new market with cultural contents and train local specialists. In order to search for the ways to maintain Korean contents in other nations and expand exportation. cooperations invite leading cultural contents groups to South Korea, let the groups experience Korea's contents. Cooperations initiated invite training, dispatch training by Korean companies and international students training. The purpose of this paper is to support education system, ETS-CS(Educational Training System for Contents Specialist) and analyse practices applied in the field to develop a better cultural contents industry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.05a
• /
• pp.65-68
• /
• 2003

Interconnected power system operation has given rise to the problem of increased fault levels and leads to over stressing of all the components. Use have been made of recently developed high Tc superconductor in devising a superconducting fault current limiter (SFCL) that promises optimum performance in terms of capital cost, size, auto sensing, operational losses, response time and reliability. Recently, research about the application of the SFCL is actively progressing in Korea. To be applied for SFCL practically, the electrical insulation design of SFCL must be developed. Therefore, this paper presents the result of an investigation of the dielectric characteristics of turn-to-turn insulation for SFCL in liquid nitrogen. The dielectric characteristics of turn-to-turn insulation models of SFCL were investigated. We obtained following results. The breakdown voltages increased as the spacer thickness and length increased. And the breakdown voltages of turn-to-turn model without spacer were higher than the breakdown voltages of turn-to-turn model with spacer under impulse as well as AC voltages. The information gathered in this test series should be helpful in the design of liquid nitrogen filled SFCL.