• Tribology and Lubricants
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• v.8 no.1
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• pp.63-69
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• 1992

In order to gain better understanding of wear behaviors of TiN-coated boron cast iron, tests and analyses were conducted with block-on disc type tribometer. TiN layer of thickness $2 \mu m$ and $4 \mu m$, coated by cathodic arc evaporation process, were experimentally investigated with the variation of applied load and sliding speed under dry sliding condition. Wear characteristics were expressed in terms of the three-dimentional wear map as well as the wear rate vs sliding speed and load. Comparisons of wear and friction characteristics between coated cast irons and uncoated cast irns were also made. Wear mechanism of TiN layer was explained in view of surface interaction between the mating surfaces. The thicker coating exhibited higher hardness and adhesion strength. the significance of stresses at the surface and in the subsurface was briefly discussed in relation to the wear behavior.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.526-529
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• 2006

In this paper, flexure behavior of steel fiber reinforcement ultra high performance cementations composites (SFR-UHPCC) has been analyzed by equivalent stress block. Pulling-out tensile force of steel fiber with concrete matrix was induced. An appropriate flexure evaluation formula, i.e. semi-analytical formula, was established based on rectangular cross section beam for comparing with shear capacity and ultimate load of SFR-UHPCC beam. Finally, the semi-analytical formula has been simplified for the convenience of design work. Experimental results and theoretical shear strength are shown to compare with the formula proposed by this paper. The theory formula has a good prediction of failure type of SFR-UHPCC.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.767-770
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• 2000

A novel process is newly developed for building RP(Rapid Prototyping) parts using a sheet lamination technique. The build process of existing sheet lamination type RP machines consists of the following steps : feeding, lamination and cutting. In this process, the laminated part of an object is often scratched by a cutter or damaged by a laser beam due to the cutting operation preceded by lamination, In addition, decubing of the unused portion from the laminated block is difficult. In the new process, cutting operation is performed before lamination. The cutting operation takes place while a paper sheet is firmly attached on the plate using electrostatic force. Then liquid glue is applied to the calculated region of the given contour for lamination. The process aims to manufacture a $2k RP machine, what we call the Freeform Mater I, that can use A4 or latter-size used papers. A prototype machine that demonstrates the design concept is built and further research issues are discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1181-1186
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• 2000

The crack of concrete induced by the heat of hydration is a serious problem, particularly in concrete structures such as biers, thick walls, box type walls, mat-slab of nuclear reactor buildings, dams or foundations of high rise buildings, etc.. As a result of the temperature rise and restriction condition of foundation, the thermal stress which may induce the cracks can occur. Therefore the various techniques of the thermal stress control in massive concrete have been widely used. One of them is prediction of the thermal stress, besides low-heat cement which mitigates the temperature rise, design change which considers steel bar reinforcement, operation control and so on. In this study, firstly it introduce the thermal cracks control technique by employing low-heat cement concrete, thermal stress analysis considering season. Secondly it shows the application of the cracks control technique like block placement.

• Magazine of the Korean Society of Agricultural Engineers
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• v.36 no.3
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• pp.135-143
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• 1994

The actural condition of rural house polts, houses and their attached facilities was surveyed in CHUNGCHEONGBUK-DO in order to find out existing residential problems. From the data collected, general influencing factors, housing/residential environmental qualities, and farmer's opinion on them were analyzed or obtained as the basic design criteria for future projects. The structural shape of rural housing should be developed on the basis of our traditional one. The materials of wall should be made from soil sourced one. Kitchin room and rest room should be improved in view of the Western style. Residential space should be harmonized our traditional one(reception of a guest preferred) with westernized living space(nuclear family life preferred). The plane planning of 'ㄷ' type would be generally preferred in the block planning of rural housing and attached facilities. Livestock pens and compost houses would be seperated from, while storehouses would be coexisted with a living space.

• International Journal of Advanced Culture Technology
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• v.9 no.4
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• pp.392-401
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• 2021

When a data file is shared through various methods on the Internet, the data file may be damaged in various cases. To prevent this, some websites provide the checksum value of the download target file in text data type. The checksum value provided in this way is then compared with the checksum value of the downloaded file and the published checksum value. If they are the same, the file is regarded as the same. However, the checksum value provided in text form is easily tampered with by an attacker. Because of this, if the correct checksum cannot be verified, the reliability and integrity of the data file cannot be ensured. In this paper, a checksum value is generated to ensure the integrity and reliability of a data file, and this value and related file information are stored in the blockchain. After that, we will introduce the research contents for designing and implementing a system that provides a function to share the checksum value stored in the block chain and compare it with other people's files.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.841-848
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• 2021

This study investigated the acceleration characteristics of rock slopes when earthquakes, which have not been studied much in Korea, occur. The rock slope was modeled with a similar raw of 1/20 in consideration of the height(10m), roughness, strength, and the joint dips(20°). After the completion of the model, a shaking table tests was conducted according to the magnitude of the acceleration and the type of seismic wave. The maximum acceleration was greater in the short-period seismic wave than in the long-period seismic wave, and the maximum acceleration was larger in the small acceleration. The rock slope was close to a rigid block and a structure more vulnerable to the long period wave than to the short period wave. In the event of an earthquake smaller than the domestic earthquake-resistant maximum design acceleration(0.154g), safety management of the rock slope was required.

• Journal of the Korean Institute of Telematics and Electronics
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• v.17 no.6
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• pp.51-57
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• 1980

Any switching function can be constructed with universal building block of MAND gate. Threelevel AND-NOT logic networks with only true inputs are called TANT networks. Systematic approach to TANT minimization starts from the UF type minterm with the smallest subscript and ends when UF type minterms are all covered. Optinal PEI is composed of CPPI or EPPi without C-C table. The algorithm in this work is usful in solving TANT optimization porblem of four or five variables by hand solution. When variable are six or more, it is required to be solved by computer, A CAD software package of this algorithm with FORTRAN IV language is made to solve such problems.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1765-1768
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• 2005

Binary-search 알고리즘을 이용한 새로운 6-bit 300MS/s ADC 를 제안 하였다. 본 연구에서 제안된 ADC 는 저전력, 고속동작, 저해상도의 응용분야에 적합하도록 설계 되었다. 11 개의 rail-to-rail 비교기와 기준전압 발생기, 그리고 기준전압 제어회로로 구성 되었으며, 이는 기존의 구조와는 다른 전혀 새로운 형태로 제안된 것이다. 전력소모를 줄이기 위해 비교기 공유기술을 사용하였다. 또한 ADC 의 sub-block 인 rail-to-rail 비교기는 인버터 logic threshold 전압 값을 이용한 새로운 형태의 비교기를 제안하였다. 비교기는 인버터와 n-type preamp, p-type preamp 그리고 각각에 연결되는 latch 로 구성되었다. 기존의 rail-to-rail comparator 에 비해 입력 범위 전체 영역에서 일정한 gm 값을 얻을 수 있다. 실험결과 2.5V 공급전압에서, 17mW 의 전력 소모를 보이며, 최대 304MS/s 의 데이터 변환율을 가진다. INL 과 DNL 은 입력신호가 2.38Mhz 의 주파수를 가지는 삼각파일 때, 각각 ${\pm}0.54LSB$, ${\pm}1LSB$ 보다 작다. TSMC 0.25u 공정을 이용하였다.

• Journal of Fashion Business
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• v.12 no.3
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• pp.136-152
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• 2008

The purpose of this study was to provide dress forms and jacket blocks for adult males based on the analysis of their somatotypes. As the result of the research conducted for this study that was based on 1290 males of 20 to 54 years-old, the shapes of adult male were 20 and each body shape was classified by size factor, height and chest girth. Also, master sizes were selected considering appearance frequency. XS type (master size: height 165cm and chest circumference 88cm), Yd type (master size: height 170cm and chest circumference 91cm), YI and AD2 types (master size: height 170cm and chest circumference 94cm) were selected to develop dress forms and their jacket blocks in this study. The procedure and results were follows; 1. The dress forms of XS, Yd, YI and AD2 types were produced base on means of 61 body measurements and cross sections of shoulder, chest, waist, hip of subjects belong to each somatotype. 2. New jacket blocks for XS, Yd, YI and AD2 types were developed based on the body surface developments through draping and the results of comparative investigation on the existing jacket blocks by wearing test. Also the drafting methods of new jacket blocks were provided. 3. The sensory evaluation by wearing test showed that the developed jacket blocks were estimated more highly in terms of chest's allowance, the front width's allowance, neck wrinkle, front allowance and overall appearance's fitness items than existing jacket blocks.