• 공학교육연구
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• 제18권1호
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• pp.11-19
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• 2015

본 논문은 전 생애주기에 걸쳐 나타나는 우리나라 과학기술인력의 경력이탈 규모와 현황을 추정하는 데 일차적인 목적이 있다. 이를 위해 먼저 과학기술인력의 경력이탈에 대한 조작적 정의를 내리고 이를 분석할 수 있는 기본틀을 크게 인재확보 단계와 활용단계로 구분하여 구축하였다. 이 틀에 입각하여 경력이탈 현황을 진단해 본 결과, 우리나라 과학기술인력의 경력이탈은 주로 활용단계에서 나타나고 양적 이탈보다는 창조경제시대를 이끌어갈 우수 인재의 이탈이라는 질적 이탈 문제가 심각한 것으로 나타났다. 마지막으로 생산가능인구 감소시대를 맞이할 경우 이러한 질적 이탈 문제는 더욱 심각해질 수 있으므로, 좋은 일자리 확보와 경력개발 경로 구축 등의 정책을 우선적으로 추진할 필요가 있다는 대안을 제시하고 있다.

• KIEE International Transactions on Electrophysics and Applications
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• 제3C권4호
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• pp.140-145
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• 2003

The influence of microstructure nonuniformity on the electrical characteristics of ZnO varistors was analyzed with the added amount of $Al_2$O$_3$ dopants. $Al_2$O$_3$ doping can effectively inhibit grain growth. When $Al_2$O$_3$ content is in the range between 0-0.1 %, the average grain size and the standard deviation decrease quickly and the grain growth is strongly inhibited. Therefore, it is possible to increase the microstructure uniformity by accurate addition of $Al_2$O$_3$ to the ZnO varistor. The breakdown voltage increases with the decrease of standard deviation. The greater the uniformity of the Zno varistor means the higher the global breakdown voltage. The $Al_2$O$_3$ dopants having about 0-0.023 wt% content can effectively improve the voltage ratio, and the voltage ratio reaches a minimum value of 2.32 at an $Al_2$O$_3$ content of 0.005 wt%.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.961-966
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• 2000

It is difficult to change or remedy concrete structure after hardened. It is usual to evaluate the quality of hardened concrete using several test method. This study was performed to make fundamental data that could be used to evaluate the quality of hardened concrete. This study is to estimate mix proportion of hardened concrete. Each elements of concrete needed different estimation methods. First, the cement that handled by the most important compounds measured by XRF(X-ray fluorecence) machine with scanning Ca-K${\alpha}$. Second, the coarse aggregate that divided by maximum size measured by the area comparison method that starts from the assumption of uniform distribution. Third, the fine aggregate measured by the weight comparison method that needs several prerequsite constants which concerned cement hydration reaction. Fourth, the water content would be estimated by expert system that has data base of design data, the contents of above estimation results, the characteristics of concrete strength. As the result of the above research, some conclusions are as follows. The cement estimation method resulted by reliability of mean 96.7%, standard deviation 3.92. The area comparison method resulted by reliability of mean 95.3%, standard deviation 2.08. The weight comparison method resulted by reliability of mean 93.3%, standard deviation 3.35.

• 복식문화연구
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• 제13권4호
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• pp.646-657
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• 2005

The purpose of this study was to analyze the problems of brands preferred by adolescents on sizing system and grading method and to provide a basic information for adolescent apparel manufacturers. Brands preffered by adolescents were obtained via a questionnaire from adolescents aged from 13 to 18 in Seoul and finally we selected upper 12 brands out of 20 brands they preffered. Also the graders of 12 brands were surveyed through direct interviews. The results indicated only 2 brands out of 12 brands(such as Adidas and Basic House) manufactured apparels for adolescents and most brands targeted customers in their early twenties as a main target market. As a results of researching the sizing system of 12 brands, women's apparel brands produced two sizes separately for upper and lower garments, unisex apparel brands produced garments in 4${\~}$8 sizes. For most of the brands, each size has a dimensional deviation on the same rate in all parts and 12 brands manufactured garments mainly with a dimensional deviation of 5cm in bust circumference and hip circumference.

• Journal of Power Electronics
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• 제15권4호
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• pp.861-875
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• 2015

This paper presents a wide frequency range LLC resonant controller IC for LED backlight units. In this paper a new phase-domain resonance deviation prevention circuit (RDPC), which covers a wide frequency and input voltage range, is proposed. In addition, a wide range gate clock generator and an automatic dead time generator are proposed. The chip is fabricated using 0.35 μm BCD technology. The die size is 2 x 2 mm2. The frequency of the clock generator ranges from 38 kHz to 400 kHz, and the dead time ranges from 300 ns to 2 μs. The current consumption of the LLC resonant controller IC is 4 mA for a 100 kHz operation frequency using a supply voltage of 15 V.

• 한국산림과학회지
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• 제4권1호
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• pp.24-25
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• 1965

수확표조제시(收穫表調製時) 조사(調査)한 표준지(標準地)의 크기는 $40m{\times}40m$ 이하(以上)이어야 한다. 이것보다 작으면 과대(過大)한 평균치(平均値)를 주며 임분(林分)의 구조(構造)가 균일(均一)한것 같이 보이기 쉬우므로 자료음미시(資料吟味時) 기각상임분(棄却象林分)이 채용(採用)될 우려(憂慮)가 있다. $40m{\times}40m$ 크기에서는 우려(憂慮)는 없다.

• Journal of Biosystems Engineering
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• 제21권4호
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• pp.449-455
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• 1996

The temperature distributions at various soil depths were predicted by heat transfer model during and after infrared irradiation on sand loam or loam soil. At each soil depth, predicted and measured temperature distributions were compared with using the mean relative percentage deviation and standard error. The mean relative percentage deviation was less than 10% between predicted and measured temperature distributions at each soil depth. Thus, it was concluded that the temperature distribution at each soil depth could be predicted satisfactorily by heat transfer model. Also, it is expected that these predicted temperature distributions can be used as basic information for determining the working speed of weeder and the size when the real weeder is constructed.

• 대한산업공학회지
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• 제30권2호
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• pp.159-164
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• 2004

Lot-streaming is the process of splitting a job (lot) into a number of smaller sublots and then scheduling these sublots in order to accelerate the completion of jobs in a multi-stage production system. Anew genetic algorithm (NGA) is proposed for an-job, m-machine, equal-size sublot lot-streaming flow shop scheduling problem with delivery windows in which the objective is to minimize the mean weighted absolute deviation of job completion times from due dates. The performance of NGA is compared with that of an adjacent pairwise interchange (API) method and the results of computational experiments show that NGA works well for this type of problem.

• Journal of Welding and Joining
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• 제19권5호
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• pp.486-491
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• 2001

The effect of S content in welding wires on spattering characteristics and droplet transfer phenomena was studied. In MAG welding using 80%Ar-$20%CO_2$ shielding gas, spattering characteristics and droplet transfer phenomena were varied with S content of wire. Sulfur addition in wire reduced surface tension of droplet and weld pool, and made arc more stable in MAG welding. With increasing S content, the spattering ratio and the ratio of large size spatter ($d{\geq}1.0mm$) were reduced in short circuit transfer mode. In spray transfer mode, spattering ratio, however was increased when sulfur was added more than 0.020wt.% because surface tension of droplets and weld pool was reduced too much even though arc stability was improved.

• 산업기술연구
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• 제28권B호
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• pp.185-191
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• 2008

This study tried the 1st, 2nd dimensional numerical analysis according to the pier's shape, size and installing method in order to compare the depth of scour calculation method using the variables calculated by using the 2nd dimensional numerical analysis with the calculated depth of scour value by using the calculated variables by using the 1st dimensional numerical analysis. And then verified the problems occurring when the depth of scour is calculated by using the calculated values by using the 1st dimensional numerical analysis, as calculating the deviation depending on it.