• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.11
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• pp.1087-1093
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• 2010

The satellite thermal control H/W composed of two parallel channels working for heat pipe (HP) and phase change material (PCM) is suggested for the high heat dissipating component which works intermittently with short duty. In a limited point of view, the HP-PCM device is a kind of off-the-shelf component that requires no dedicated configuration and thermal designs to PCM. Therefore, it can be used with less impact on the program cost and schedule different from most of the PCM applications. In present study the typical honeycomb structure radiator applying the HP-PCM device is designed and the detail thermal math model is developed for numerical analyses. The result comparison between without and with PCM shows that the HP-PCM device redistributes the peak heat around the whole mission period through the alternate melting and freezing of PCM, and, as a result, the maximum and minimum temperatures are effectively alleviated. The drawback of PCM application due to low thermal conductivity can be successfully resolved by means of parallel arrangement of HP channel.

• Journal of Satellite, Information and Communications
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• v.5 no.2
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• pp.25-28
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• 2010

The need for multiband RF front-end in modern communication system is growing rapidly. For example, satellite system always uses a complex arrangement of frequency plans and consequently needs filters for each communication channel and it will be ideal to have a single filter module that does jobs of all those channel filters to reduce the size and payload of the system. In this paper, a new method to transform four-port self-feedback balanced dual-band bandpass filter into two-port is proposed. The two-port balanced dual-band bandpass filter which has baluns at the input and output ports and the fundamental frequency at 2.5 GHz and the first harmonic frequency at 5.7 GHz is fabricated and measured. Good agreement between measured and simulated results was achieved.

• Science of Emotion and Sensibility
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• v.10 no.3
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• pp.331-342
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• 2007

This study focused on developing MP3 smart clothing products and usability evaluation. MP3 smart clothing which was developed in this study contains e-textile keypad and a kit. The kit consists of MP3 Player, remote controller module and ear phone, and are easy to assemble and dismantle. And usability evaluation about MP3 smart Clothing which was developed in this study contains e-textile keypad and a kit. For making the MP3 Smart clothing, e-textile signal line and keypad was developed and a metal connection ring also was manufactured to adhere closely e-textile signal line to keypad. The last products are two kinds of MP3 smart clothing, jacket style of MP3-YSJ(Yonsei Smart Jacket) and safari style of MP3-YSS(Yonsei Smart Safari). Then usability evaluation conducted two times about MP3 smart clothing developed. Usability evaluation is classified by a module evaluation and an item evaluation. The module evaluation measured external appearance, material, a music controller, an ear phone(or a mini speaker) and connector. The item evaluation measured social acceptance, feeling of wearing, utility, easiness of maintenance and safety. The module evaluation described totally positive results in the first usability evaluation about MP3-YSJ 1.0 and MP3-YSS 1.0. The item evaluation shows a lower score in the social acceptance, especially the easiness of connector maintenance and the social acceptance of music-controller in MP3-YSJ 1.0 and MP3-YSS 1.0. The second usability evaluation conducted with improved products by the first usability test results. Results from second item evaluation indicated needs to improve the easiness of connector & music-controller maintenance and the social acceptance of music-controller in MP3-YSJ 2.0. In MP3-YSS 2.0, the easiness of material management and the social acceptance of music controller & connector needed to improvement. In particular, users felt inconvenience in the social acceptance because of e-textile keypad arrangement. To outweigh this disadvantage, further study is needed about keypad interface of the music controller.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.10
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• pp.881-887
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• 2014

Micro-sized Peltier coolers are generally employed for uniformly distributing heat generated in the multi-chip packages. These coolers are commonly classified into vertical and planar devices, depending on the heat flow direction and the arrangement of thermoelectric materials on the used substrate. Owing to the strong need for evaluation of performance of thermoelectric modules, at present an establishment of proper theoretical model has been highly required. The design theory for micro-sized thermoelectric cooler should be considered with contact resistance. Cooling performance of these modules was significantly affected by their contact resistance such as electrical and thermal junction. In this paper, we introduce the useful and optimal design model of small dimension thermoelectric module.

• Archives of design research
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• v.15 no.4
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• pp.129-138
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• 2002

Against the projection that the volume of filing would be drastically cut in the Information Age, the needs for filing in this age increases gradually. In this respect, it is critical to study the design of office filing system furniture. Through this study, we could find out what shall be the major requirements for office lijillg system furniture. This study would also provide important raw data for developing more efficient and more satisfactory office filing system furniture. Subject for this study includes 6 representative filing system furniture including a lateral file cabinet. For the design analysis, we used catalogues of foreign and domestic office furniture, particularly filing system furniture. The analysis is classified into the following six categories such as size, shape, color, material, handle, and filing method, mobility, flexibility, and so on. According to the analysis of office furniture in the market, requirements of furniture fit for office environment are found to be as follows. -Instead of the fixed-type furniture, movable furniture is more adaptable to the ever-evolving office environment. -Design the office furniture in accordance with a standardized module would provide a more unity and diversity of arrangement in space particularly when it is arranged with other furniture. -Development of more diverse color, which ranges from achromatic color to wooden color to other various colors, is more favored in the ever-changing office environment. -As the grip provides a variety of image to the furniture let alone its function, its development is required to be more diverse and more conforming 10 the design of Ihe furniture. -The filing methods in general are with drawer and shelf, among which the drawers design is usually fixed. However, under the evolving office furniture environment, the design of Ihe drawer, bolh inlerior and exterior, shall be more diverse and flexible.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.761-770
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• 2017

The objective of this study is to propose a community facility design for the revitalization of the piloti spaces of deteriorated low-rise residential blocks. For this study, the precedent research and institutional limitations are examined. In addition, this study selected and analyzed a deteriorated low-rise residential block utilizing pilotis. Generally, in this type of residence, 8 to 10 generations live together in multi-family houses and row houses, so it is a type of housing that lacks both public space and parking places. Therefore, we attempted to improve the situation of the communities by making use of the space between the pillars and walls without infringing on the parking places. In addition, we took into consideration the design and arrangement of the piloti by evaluating the inconveniences and needs of the residents through interviews. Specifically, various modules were planned and used to transform the spaces between the pillars of the pillar type piloti structure. This study examined the possibilities offered by various materials and modules, and studied the diverse possibilities that can be offered by changing the modules.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.60-67
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• 2021

In lately, it's been developed and used a system of using deck plates as formwork in order to solve various problems caused by conventional formwork system. This system is more economical and has higher constructability than the conventional system by permanently embedding most of deck plates into the members. However, for this kind of embedded deck plates formwork system, it's been reported that it is difficult to verify filling of concrete in members like beams with narrow width and complicated rebar arrangement. In addtion, there are several problems such as corrosion of deck plates in terms of constructability and maintenance. Therefore, in this study, it is attempted to develop a removal-deck plate formwork system for beams by removing deck plates after concrete curing. The system consists of a deck plate module that acts as form, a frame preventing deformation by concrete lateral pressure, stirrup frame, and connector that combines these. As a result of this research, it is verified that it has higher constructability, efficiently prevents deformation caused by concrete lateral pressure and could be easily removed in the developed formwork system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.5 s.108
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• pp.461-475
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• 2006

In this paper, it is described about the tri-band mobile antenna system design to provide broadband multimedia and direct broadcasting services using goo-stationary Koreasat 3, simultaneously operated in Ka/K/Ku band. The radiating part of the antenna system with a fan beam characteristic in the elevation plane is composed of the quasi-offset dual shaped reflector and the tri-band feeder. The tri-band feeder is also composed of the Ka/K dual band feeder with the protruding dielectric rod, the circular polarizer, the ortho-mode transducer and the circular-polarized Ku band feed array. Especially, the Ka/K dual band circular polarizer was realized firstly using the comb-type structure. For fast satellite-tracking on the movement, the Ku band feed array has the structure of the $2{\times}2$ active phased array which can make electrical beams. And, the circular-polarized characteristic in the feed array was improved by $90^{\circ}$ rotating arrangement of four radiating elements polarized circularly by a $90^{\circ}$ hybrid coupler, respectively. Four beam forming channels to make electrical beams at Ku band are divided into the main beam channel and the tracking beam channel in the output, and noise temperature characteristics of each channel were analyzed on the basis of the contributions of internal sub_units. From the fabricated antenna system, the output power at $P_{1dBc}$ of Ka_Tx channel was measured more than 34.1 dBm and the measured noise figures of K/Ku_Rx channels were less than 2.4 dB and 1.5 dB, respectively, over the operating band. The radiation patterns with co- and cross-polarization in the tri-band were measured using a near-field measurement in the anechoic chamber. Especially, Ku radiation patterns were measured after correcting each initial phase of active channels with partial radiation patterns obtained from the independent excitation of each channel. The antenna gains measured in Ka/K/Ku band of the antenna system were more than 39.6 dBi, 37.5 dBi, 29.6 dBi, respectively. And, the antenna system showed good system performances such as Ka_Tx EIRP more than 43.7 dBW and K/Ku_Rx G/T more than 13.2 dB/K and 7.12 dB/K, respectively.