• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.9
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• pp.468-474
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• 2003

This paper describes the development of an open frame type high power density switching converter. It is based on the active clamp forward converter with synchronous rectifier, and packaged by using the open frame and multi-layer printed circuit board (PCB) technology to achieve the higher power density. Furthermore, the windings of transformer and inductor are also realized by multi-layer PCB so that it also contributes to achieve higher power density. Through the experiment on the prototype converter of 50[W], it is confirmed that power density of 50[W/i$n_3$] and maximum efficiency of over 91[%] are obtained.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.6
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• pp.1-8
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• 2008

This paper introduces three efficient frame selection schemes to reduce the computation complexity for the multi-reference and variable block size Motion Estimation (ME). The proposed RSP (Reference Selection Pass) scheme can minimize the overhead of frame selection. The MFS (Modified Frame Selection) scheme can reduce the number of search points about 18% compared with existing schemes considering the motion of image during the reference frame selection process. In addition, the TPRFS (Two Pass Reference frame Selection) scheme can minimize the frame selection operation for the variable block size ME in H.264/AVC using the character of selected reference frame according to the block size. The simulation results show the proposed schemes can save up to 50% of the ME computation without degradation of image Qualify. Because the proposed schemes can be separated from the block matching process, they can be used with any existing single reference fast search algorithms.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.378-383
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• 2008

Bogie frame of the locomotive is an important structural member for the support of vehicle loading. A lot of study has been carried out for the prediction of the structural integrity of the bogie frame in experimental and theoretical domains. The objective of this paper is to estimate the structural integrity of the bogie frame. Strength analysis has been performed by finite element analysis. From these analysis, stress concentration areas were investigated. For evaluation of the loading conditions, dynamic stress were measured by using strain gage. It has been found that the stress and strain due to the applied loads were multi-axial condition according to the location of strain gage. The fatigue strength evaluations of the bogie frame are performed to investigate the effect of the multi-axial load through the employment of the critical plane approach.

• Journal of the Korean Wood Science and Technology
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• v.19 no.3
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• pp.45-52
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• 1991

To investigate opportunities for wood frame housing and to activate wood frame house construction, trends of construction activities. preference about housing, and building codes related to wood frame housing were discussed. And two models of wood frame house were developed and construction cost was analyzed to compare with comparative masonry houses. The results obtained were as follows: 1. While 77.8% of people prefer single-family houses, majority of people(74.9%), ironically, possess multi-family houses such as apartments Wood work cost was ratio of 4% of total building cost. while wood material cost accounted merely for 11 % out of total building material cost. 2. Building code was not major barrier to residential house at height under 13m. The building code regulated major structural member and family boder wall of multi-family house to be built with fire retardant material. 3. The proper wood frame house was analyzed of town house or villa type locating in suburban of big city with hot ondol system for the upper middle class. 4 There was no difference in construction cost between western style wood frame house and comparable masonry house, but construction cost for Korean style wood frame house is 27% higher than that of comparable masonry house. It was necessary to reduce materials and cost down by prefabrication technique for both style of wood frame house.

• Journal of Korean Society on Water Environment
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• v.20 no.4
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• pp.307-312
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• 2004

This study was focused on experiment for the separation and concentration process of Cu(II), Zn(II) solution with the variation of applied pressure and concentration using reverse osmosis plate and frame modules. Rejection coefficient and degree of concentration for Cu(II) component using single and multi-stage reverse osmosis process were showed 96.3~97.8%, 0.044~0.191(in single-stage), 96.3~98.4%, 0.400~2.264(in multi-stage) within the range of experimental condition, respectively. Those of Zn(II) were 93.3~97.1%, 0.019~0.395(in single-stage), 96.3~98.2%, 0.365~1.454(in multi-stage), respectively. Degree of concentration of multi-stage were higher than those of single-stage. Heavy metal[Cu(II), Zn(II)] separation was very efficient in using reverse osmosis plate and frame type modules. Separation efficiency for a mixed solution Cu(II) and Zn(II) was higher than those of each one of Cu(II) and Zn(II).

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.5
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• pp.430-442
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• 2013

This paper presents a fast multi-reference frame integer motion estimator for H.264/AVC. The proposed system uses the previously proposed fast multi-reference frame algorithm. The previously proposed algorithm executes a full search area motion estimation in reference frames 0 and 1. After that, the search areas of motion estimation in reference frames 2, 3 and 4 are minimized by a linear relationship between the motion vector and the distances from the current frame to the reference frames. For hardware implementation, the modified algorithm optimizes the search area, reduces the overlapping search area and modifies a division equation. Because the search area is reduced, the amount of computation is reduced by 58.7%. In experimental results, the modified algorithm shows an increase of bit-rate in 0.36% when compared with the five reference frame standard. The pipeline structure and the memory controller are also adopted for real-time video encoding. The proposed system is implemented using 0.13 um CMOS technology, and the gate count is 1089K with 6.50 KB of internal SRAM. It can encode a Full HD video ($1920{\times}1080P@30Hz$) in real-time at a 135 MHz clock speed with 5 reference frames.

• IE interfaces
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• v.12 no.2
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• pp.174-179
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• 1999

This paper describes the development of low cost, miniaturized multi-function image splitter for an unmanned guard system. The essential equipments of an image splitter system consist of a video system which displays in one screen images inputted by several cameras, a frame switcher which records each image sequentially in VTR, and TBC(Time Base Control) system which prevents image flickering during image switching. Currently, the price of similar system on the market is high, system management and repair are difficult, and bulky space is required. Futhermore, since currently available frame switcher can record only 30frame/sec, if eight cameras are installed, each camera image is recorded at the low speed of 3.75frame/sec, and consequently skip some images which may be vital for legal evidence. In this research, we have solved the problem of low speed recording by recording the video screen of splitted images at 30frame/sec and zooming each image when play back.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.520-523
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• 2009

The drive towards lowering costs and increasing frame rates results in new panel designs and thereby new photomasks designs. One common way to reduce cost is to reduce the number of production steps. For this multi tone photomasks (MTM) are needed. MTMs contain more information and increases photomask placement requirements. Increasing frame rates lead to shrinking geometries. The combination of HTM and shrinking geometries drastically increases the requirements imposed on the pattern generators used to print the photomasks. New methods are therefore needed to enable future photomask manufacturing. This paper introduces three advanced image quality enhancing methods.

• Korean Architects
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• no.11 s.82
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• pp.22-25
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• 1975

The aim of this study is the introduction of simplified method for the design stress analysis of multi-span gable frame structures with crane supports. Under the author's assumptions made previously for the same structures of single span, simplified stress analysis and exact computer analysis are excuted for some multi-span sample structures. Comparing the results of both stress analysis and with some modifications, a feasible simplified method for the design stress analysis of multi-span gable frame structures with crane supports is established.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9A
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• pp.837-843
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• 2006

IEEE802.15.3 and IEEE802.15.4 have defined the hybrid MAC protocols based on TDMA and CSMA where a multi-frame TDMA structure is employed so that multiple data frames can be transmitted within one timeslot to guarantee minimum delay bounds of isochroous traffic. However, TDMA has an intrinsic problem that cannot dynamically allocate optimal length of timeslot to each station. Therefore the idle timeslot can be produced by stations when each transmission queue is instantaneously empty during its timeslot, which would waste lots of timeslots especially in the multi-frame TDMA systems. In this paper, we propose a more flexible multiple-access scheme for the multi-frame TDMA system based on the concept of virtual slot which is accessible by every station with the highest priority for slot owner and lower priority for other stations. Finally, our simulation results from various environments show that proposed scheme can achieve magnitude improvement of total system throughput and average message delay by maximizing channel utilization.