• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.310-315
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• 2008

Authors design a rotary-type small-scaled linear induction motor(LIM) and a performance test machine before manufacturing a real-scaled LIM for a railway transit. The designed LIM is a single-sided, short primary type and its primary has 4 poles. The rated power is 10(kW). In order to analyze characteristics of the LIM, authors use a mixed 2D-3D FEM analysis. 3-D FEM analysis is used for calculating a distribution of eddy-current on the semi-caped AL-sheet of the secondary reaction. Authors calculate a correction factor of conductivity and an equivalent conductivity on the secondary AL-sheet using a normalized eddy-current. The equivalent conductivity which is calculated in this way includes a transverse edge-effect of the LIM. Authors apply the equivalent conductivity on the secondary AL-sheet of 2D-FEM model and get performance characteristics of the LIM. Basic characteristics such as thrust and normal force, input current, efficiency and power factor of the LIM have been analyzed with the variation of frequency and speed. In order to apply an air-gap control system, the variation of the basic characteristics have been analyzed with the air-gap length variation of the LIM. Finally, authors introduce an operation mode using the air-gap control system and conduct a research on feasibility of the system.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.587-590
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• 2003

The first attention in designing a transformer for low temperature rise should be to reduce losses. Leakage inductance and temperature rise are two of the more impotent problems facing the magnetic core technology of today's high frequency transformers. Excessive leakage inductance increases the stress on the switching transistors and limits the duty-cycle, and excessive temperature rise can lead the design limitation of high frequency transformer with high current. The flat transformer technology provides a very good solution to the problems of leakage inductance and thermal management for high frequency power. The critical magnetic components and windings are optimized and packaged within a completely assembled module. The turns ratio in a flat transformer is determined as the product of the number of elements or modules times the number of primary turns. The leakage inductance increase proportionately to the number of elements, but since it is reduced as the square of the turns, the net reduction can be very significant. The flat transformer modules use cores which have no gap. This eliminates fringing fluxes and stray flux outside of the core. The secondary windings are formed of flat metal and are bonded to the inside surface of the core. The secondary winding thus surrounds the primary winding, so nearly all of the flux is captured.

• 정보교육학회논문지
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• 제9권1호
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• pp.139-146
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• 2005

최근 초 중등학교에서는 웹을 교실 수업에 적극적으로 활용하고 있다. 웹을 활용하기 위해서는 필수적으로 웹 브라우저를 이용하여야 하는데, 대부분의 교실에서는 마이크로소프트사에서 제공하는 인터넷 익스플로러 웹 브라우저를 사용하고 있다. 이 웹 브라우저는 일반인을 위한 것으로 초 중등학교 교실 수업에서 필요한 기능은 부족한 면이 적지 않다고 할 수 있다. 이와 같은 부족한 점을 해소하기 위하여, 본 연구에서는 기존에 사용하던 인터넷 익스플로러 웹 브라우저의 불편한 점과 이에 대한 개선 방안을 제시하고 이를 설계에 반영하여 실제 사용 가능한 웹 브라우저를 구현하였다. 구현한 웹 브라우저는 초 중등학교 현장 적용을 통해 높은 사용자 만족도가 있음을 확인하였다. 이 웹 브라우저는 우리나라의 초 중등학교 교사와 학생들에게 웹을 보다 효율적이고 효과적으로 수업에 활용하는데 도움을 줄 수 있을 것으로 기대된다.

• 대한전기학회논문지
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• 제39권5호
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• pp.445-452
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• 1990

In order to design a conveyer system which is driven by short primary single sided linear induction motors (SLIM), the thrust force characteristics of SLIM have been calculated from the fundamental equation based on Maxwell's electromagnetic equation and by varying the various design parameters. A conveyer system of moving secondary has been constructed using the design values obtained by the simulation and these values are compared with the experimental values. The control method of the conveyer system is also proposed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.2053-2058
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• 2004

The pressurized light water cooled, medium power (330 MWt) SMART (System-integrated Modular Advanced ReacTor) has been under development at KAERI for a dual purpose : seawater desalination and electricity generation. The SMART design verification phase was followed to conduct various separate effects tests and comprehensive integral effect tests. The high temperature / high pressure thermal-hydraulic test facility, VISTA(Experimental Verification by Integral Simulation of Transient and Accidents) has been constructed to simulate the SMART-P (the one fifth scaled pilot plant) by KAERI. Experimental tests have been performed to investigate the thermal-hydraulic dynamic characteristics of the primary and the secondary systems. Heat transfer characteristics and natural circulation performance of the PRHRS (Passive Residual Heat Removal System) of SMART-P were also investigated using the VISTA facility. The coolant flows steadily in the natural circulation loop which is composed of the steam generator (SG) primary side, the secondary system, and the PRHRS. The heat transfers through the PRHRS heat exchanger and ECT are sufficient enough to enable the natural circulation of the coolant.

• Progress in Superconductivity
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• 제5권2호
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• pp.149-152
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• 2004

The design and the fabrication of a 1 MVA single-phase HTS transformer are presented in this paper, The rated voltages are 22.9 ㎸ for primary and 6.6 ㎸ for secondary, and the rated currents are 44 A and 152 A respectively. The transformer has HTS double pancake type windings. This type of winding has many advantages such as ease of fabrication and maintenance, good distribution of surge voltage and insulation of windings. Single HTS wire was used for primary winding and four HTS parallel wires were used for secondary winding. These windings are arranged reciprocally with the shell type iron core. An FRP cryostat with room temperature bore was fabricated to isolate the iron core from the coolant. The winding will be cooled down to 65 K with sub-cooled liquid nitrogen using a GM-cryocooler. The sub-cooled liquid nitrogen has advantages of good insulation because of no bubbles as well as increased current capacity of HTS wire.

• 한국산업정보학회논문지
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• 제10권2호
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• pp.21-25
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• 2005

본 연구는 인간의 정신부하작업중 반응시간이 제한된 긴급상황에서 시스템이 비정상적인 상태로 변화할 경우 인간의 수행도 특성을 살펴보고 이를 보조할 수 있는 보조장치의 설계에 도움을 주는 기준 안을 제시하고자 한다. 긴급상황에서 최우선시 되는 수행도는 반응시간보다는 시스템을 성공적으로 제어하여 비극적인 재해를 방지하는 일이다. 그러므로 여러 작업 수행도들 중에서 제어에 실패하게 되는 요인의 영향도를 알아내는 것이 중요하다. 실험결과 인간의 반응은 극히 제한된 짧은 반응시간내의 단일작업에서의 수행도는 시스템의 전체 영향도를 제대로 반영하지 못함을 알 수 있었다. 이럴 경우 부수작업을 부여했을 때 시스템의 변화 요인의 영향도를 더욱 잘 나타내는 것임을 유도하였다. 그러므로 시스템의 상황이 비 정상적인 상태로 진행될 경우, 특히 이러한 상황에서 반응해야 할 시간이 제한적일 경우 수행도 측정에는 다양한 형태의 부수작업을 개발하고 이를 이용한 측정이 더욱 효율이 있다는 점을 제시한다. 이러한 실험의 결과를 유추해보면 안전장치 기기의 설계를 위해서는 운용되는 상황에 맞는 측정방법이 개발되어야 긴급 상황의 수행도를 측정할 수 있다.

• 한국연소학회지
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• 제18권4호
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• pp.1-11
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• 2013

The oxy-fuel combustion is $CO_2$ capture technology that uses mixture of pure $O_2$ and recirculated exhaust as oxidizer. Currently some Oxy-fuel power plants demonstration project is underway in worldwide. Meanwhile research project for converting 125 MWe Young-Dong power plant to 100 MWe oxy-fuel power plants is progress. In this paper, 1 D process analytical approach was applied for conducting process design and operating parameters sensitivity analysis for oxy-fuel combustion of Young-Dong power plant. As a result, appropriate gas recirculation rates was 74.3% that in order to maintain normal rating superheater, reheater steam temperature and boiler heat transfer patterns. And boiler efficiency 85.0%, CPU inlet $CO_2$ mole concentration 71.34% was predicted for retrofitted boiler. The oxygen concentration in the secondary recycle gas is predicted as 27.1%. Meanwhile the oxygen concentration 22.4% and moisture concentration 5.3% predicted for primary recycle gas. As the primary and secondary gas recirculation increases, then heat absorption of the reheater is tends to increases whereas superheater side is decreased, and also the efficiency is tends to decrease, according to results of sensitivity analysis for operating parameters. In addition, the ambient air ingression have a tendency to lead to decline of efficiency for boiler as well as decline of $CO_2$ purity of CPU inlet.

• 패션비즈니스
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• 제26권6호
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• pp.14-31
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• 2022

Worn by both males and females the kimono is the national dress of Japan. Previous research highlights that this national dress is fading from tradition and evolves to develop with the times and fashion trends. This research aims to investigate what a kimono represents both historically and currently within Western society. The idea of the kimono being more than a national dress representing Japan, the main three themes researched will be (1) Shape (2) Narrative (3) Journey from East to West. Based on both primary and secondary sources this research indicates that there is a strong relationship between the universal increase of kimono wearers in Eastern and Western societies from history through to present day. Primary research is utilised in the form of two types of interviews. Primary outcomes bring a personal perspective to how and why kimono is worn nowadays within Europe. Secondary sources include online lectures held by kimono specialists as well as subject relevant books. From the 19th century where the Dutch were the only European country to trade with Japan, an exchange of fabrics took place which later led to the exchange of: fit, fashion and pattern (primarily within Western womenswear fashion.) This distinct garment never gets discontinued and evolves with social demands within society today.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권6호
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• pp.1379-1397
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• 2013

We consider a system where a licensed radio spectrum is shared by multiple primary users(PUs) and secondary users(SUs). As the spectrum of interest is licensed to primary network, power and channel allocation must be carried out within the cognitive radio network so that no excessive interference is caused to PUs. For this system, we study the joint beamforming and power allocation problem via game theory in this paper. The problem is formulated as a non-cooperative beamforming and power allocation game, subject to the interference constraints of PUs as well as the peak transmission power constraints of SUs. We design a joint beamforming and power allocation algorithm for maximizing the total throughput of SUs, which is implemented by alternating iteration of minimum mean square error based decision feedback beamforming and a best response based iterative power allocation algorithm. Simulation results show that the algorithm has better performance than an existing algorithm and can converge to a locally optimal sum utility.