• Progress in Superconductivity
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• 제5권1호
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• pp.50-54
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• 2003

We have fabricated $∂^2$$B_{z}$ /$∂x^2$ type planar gradiometers and studied their properties in operation under various field conditions. $YBa_2$$Cu_3$$O_{7}$ film was deposited on $SrTiO_3$ (100) substrate by a pulsed laser deposition (PLD) system and patterned into a device by the photolithography with ion milling technique. The device consists of 3 pickup loops designed symmetrically Inner dimension and the width of the square side loops are 3.6 mm and 1.2 mm, respectively, and the corresponding dimensions of the center loop are 2.0 mm and 1.13 mm. The length of baseline gradiometer is 5.8 mm. Step-edge junction width is 3.0 $\mu\textrm{m}$ and the hole size of the SQUID loop is 3 $\mu\textrm{m}$ ${\times}$ 52 $\mu\textrm{m}$. The SQUID inductance is estimated to be 35 pH. The device was formed on a 20 mm ${\times}$ 10 mm substrate. We have tested the behavior of the device in various field conditions. The unshielded gradiometer was stable under extremely hostile conditions on a laboratory bench. Noise level 0.45 pT/$\textrm{cm}^2$/(equation omitted)Hz and 0.84 pT/$\textrm{cm}^2$/(equation omitted)Hz at 1 Hz for the shielded and the unshielded cases, which correspond to equivalent field noises of 150 fT/(equation omitted)Hz and 280 fT/(equation omitted)Hz, respectively. In spite of the short baseline of 5.8 mm, the high common-mode-rejection-ratio of the gradiometer, $10^3$, allowed us to successfully record magnetocardiogram of a human subject, which demonstrates the feasibility of the design in biomagnetic studies.

• 한국의류학회지
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• 제26권1호
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• pp.133-143
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• 2002

The textile industry is petting increased effort to manufacture the value-added products that gives the differentiated characters at every level of fiber and fabric production. The color is an important element to be used strategically in order to push up the value-added design. The colors of apparel products have a close relationship with the skin colors of consumers and their preference colors. This study was carried out to cluster the skin colors of the Korean women into several similar skin colors and to analyze their preference colors by the classified groups. We measured the skin colors of 354 Korean women. With color spectrometer, JX-777, we measured 4 points of the body; cheek with removing cosmetics off, forehead, rear neck and arm on the interior part near elbow. All subjects had been shown with 40 color chips and answered the preference colors and preference colors of apparel. Data were analysed to classify skin colors using K-means Cluster Analysis and Duncan test, Frequency and Chi square test on the preference colors about the clustered 3 groups. In doing so, we used in SPSS Win 10 statistical package. Findings were as fellows: 1) The skin colors of the Korean women were clustered into YR, R, and Y skin colors. The majority of the subjects, 324 observations had YR skin colors and the subjects were classified into 3 kinds of skin color groups who had YR skin colors. 2) The average skin colors of total 324 subjects was 5.23YR 6.49/4.09 in Munsell Color System(MCS), 66.56 in L value, 10.53 in a value, and 20.67 in b value. 3) The average skin color of Type 1 was 7.98YR 6.24/4.14 in MCS, 64.10 in L value, 15.05 in a value, and 24.0 in b value. For Type 2 was 7.30 YR 6.56/3.28 in MCS, 67.24 in L value, 6.89 in a value, and 18.4 in b value, and Type 3 was 7.01 YR 7.20/4.38 in MCS, 73.53 in L value, L 16.04 in a value, and 24.87 in b value. 4) The average face color of total 324 subjects was 7.31YR 6.65/3.56 in MCS, 68.13 in L value, 9.53 in a value, and 20.18 in b value. 5) The average face color of Type 1 was 4.19 YR 6.92/5.05 in MCS, 70.78 in L value, 13.2 in a value, and 25.32 in b value. For Type 2 was 5.24YR 6.33/3.79 in MCS, 64.94 in L value, 9.84 in a value, and 19.08 in b value. Type 3 was 5.4YR 6.85/4.68 in MCS, 70.1 in L value, 11.73 in a value, and 23.92 in b value. 6) The difference of mean values between the clustered 3 skin color groups showed significantly different except the a value of neck and H value of cheeks and H value of foreheads. 7) All 3 groups showed that the most preference colors and the most preference colors of apparel was 5R 4/14. and their preference colors were much more than the preference colors of apparel.

• 대한환경공학회지
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• 제27권12호
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• pp.1305-1310
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• 2005

하상여과에서 집수관의 최적 설계를 위한 방편으로 여러 개의 모래통을 이용하여 모형 집수관 실험을 수행하였다. 집수정의 수위, 집수관의 직경, 집수관의 길이, 그리고 모래의 투수계수를 변화시키면서 모형 집수관을 운영하였으며, 집수관 표면에서의 잔류 수두와 집수관 각 부위에서의 여과수 유입율, 그리고 집수정에서의 산출유량을 측정하였다. 실험결과 모래층에서의 저항에 비해 집수관에서의 저항이 작아서 집수관 표면에서의 잔류수두가 수평에 가까운 경우 효율적인 집수관임을 알 수 있었다. 집수관의 여과수 유입율은 집수정에 근접할수록 지수함수적으로 증가하였고, 집수관의 직경이 작을수록 그리고, 대수층의 투수계수가 클수록 이 지수함수의 기울기는 증가하였다. 집수관의 길이와 직경이 증가하면 산출유량은 증가하지만 그 한계생산성은 감소하였다. 효율적인 하상여과를 위해서는 집수관에서의 축방향 유속을 줄이는 것이 중요함을 알 수 있었으며, 본 연구의 조건에서는 이 유속이 1 m/sec를 넘을 경우 우물의 효율이 크게 감소함을 알 수 있었다.

• Journal of Biosystems Engineering
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• 제43권1호
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• pp.1-13
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• 2018

Purpose: The development of compact tractors that can be used in dry fields, greenhouses, and orchards for pest control, weeding, transportation, and harvesting is necessary. The development and performance evaluation of power transmission units are very important when it comes to tractor development. This study evaluates the performance of a driving power transmission unit of a 50 kW multi-purpose narrow tractor. Methods: The performance of the transmission and forward-reverse clutch, which are the main components of the driving power transmission unit of multi-purpose narrow tractors, was evaluated herein. The transmission performance was evaluated in terms of power transmission efficiency, noise, and axle load, while the forward-reverse clutch performance was evaluated in terms of durability. The transmission's power transmission efficiency accounts for the measurement of transmission losses, which occur in the transmission's gear, bearing, and oil seal. The motor's power was input in the transmission's input shaft. The rotational speed and torque were measured in the final output shaft. The noise was measured at each speed level after installing a microphone on the left, right, and upper sides. The axle load test was performed through a continuous equilibrium load test, in which a constant load was continuously applied. The forward-reverse clutch performance was calculated using the engine torque to axle torque ratio with the assembled engine and transmission. Results: The loss of power in the transmission efficiency test of the driving power unit was 6.0-9.7 kW based on all gear steps. This loss of horsepower was equal to 11-18% of the input power (52 kW). The transmission efficiency of the driving power unit was 81.5-89.0%. The noise of the driving power unit was 50-57 dB at 800 rpm, 70-77 dB at 1600 rpm, and 76-83 dB at 2400 rpm. The axle load test verified that the input torque and axle revolutions were constant. The results of the forward-reverse clutch performance test revealed that hydraulic pressure and torque changes were stably maintained when moving forward or backward, and its operation met the hydraulic design standards. Conclusions: When comprehensively examined, these research results were similar to the main driving power transmission systems from USA and Japan in terms of performance. Based on these results, tractor prototypes are expected to be created and supplied to farmhouses after going through sufficient in-situ adaptability tests.

• 유통과학연구
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• 제14권5호
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• pp.91-96
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• 2016

Purpose - Although various studies have been conducted on the stress of service employees, there are still lack of studies regarding job stress and job satisfaction of call center workers. Especially there are quite few studies on the job stress according to employment type. This study focused on job stress and job satisfaction for call center employees and the correlation between the two factors and aimed to provide basic materials for seeking for the plans to reduce job stress and improve job satisfaction. Research design, data, and methodology - Frequency, percentage, and mean value were calculated through descriptive statistics in order to find out demographic characteristics, level of job stress, and job satisfaction. Differences in job stress according to employment type were calculated by using one-way ANOVA. Correlation between job stress and job satisfaction were identified through empirical analysis with Pearson's correlation coefficient. 150 materials were used for final analysis. The collected materials were analyzed to get statistics by using SPSS 20. Results - First, as for the job stress of call center workers, overall mean value was 2.54 in 4-point scales. Among the six sub-factors, job demands had the highest score, which was 2.67. Second, as for the job stress according to employment type, others showed higher score than mean value followed by contract job and full-time job in that order, in terms of job insecurity and organizational system. In terms of inappropriate remuneration, contract job showed higher score than mean value followed by others and full-time job. Third, as for the satisfaction with job, the mean value was 2.37 in 4-point scale and "very much satisfied" was only 3.3%. Lastly, in terms of job stress and job satisfaction, all sub-factors except for job demands showed significant correlation. The more job stress increased, the more job satisfaction decreased. Conclusions - First, as a result of analyzing job stress according to the employment type of call center workers, job stress increased more when the employment type was not full-time. Therefore, it was assumed that self-rescue efforts should be followed for effective employment management of call center business where contract employment takes most part as well as efforts to transfer them to full-time job. Second, decrease in job satisfaction of call center workers may affect the performance of an organization as well as service quality of the company providing the service. Therefore, various supports are required to decrease job stress and increase job satisfaction for call center workers through the expansion of rest area or break time. Third, I could recognize that there were lack of academic research on call center business in the whole service industry. Therefore, further research should be conducted more actively in the future. In particular, this study has special significance in the aspect that there were few studies on the job stress of call center workers according to employment type.

• 한국산학기술학회논문지
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• 제17권7호
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• pp.334-341
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• 2016

본 논문은 고 용량, Gbps급 데이터 전송을 만족하는 무선 백-홀 시스템에 적용하기 위한 도파관 개구 결합 급전 구조 안테나에 관한 내용으로 V-대역인 57GHz~66GHz 주파수 대역에서 사용 할 공동-급전 구조를 갖는 $32{\times}32$ 도파관 슬롯 서브-배열 안테나를 설계, 제작 하였다. 안테나 구성은 적층 형태로 되어있으며, 각각 복사 부(외부 홈과 슬롯, 캐비티), 개구 결합 부, 급전 부로 이루어져 있다. 안테나 설계는 3차원 유한 요소 법(FEM)을 기반으로 하는 HFSS를 이용 하였고, 안테나 제작은 알루미늄 재질로 정밀도 높은 밀링 머신을 사용하여 각 층을 가공 한 후 은(Ag)-도금 과정을 거쳐 조립하였다. 측정을 통해서 안테나의 특성을 분석한 결과 목표했던 적용 주파수 대역에서의 반사 손실은 전반적으로 -12dB이하 손실 특성을 나타냈으며, VSWR < 2.0기준으로 약 16 %에 달하는 광 대역 주파수 특성을 보였다. 측정된 안테나 복사패턴의 1차 부엽 레벨은 -12.3 dB미만 이고, 3 dB 빔 폭은 약 $1.85^{\circ}$ 로 좁은 빔 폭을 갖는다. 또한, 안테나 이득은 평균 38.5 dBi이상, 효율은 약 90% 이상으로 높은 효율을 얻었다.

• 유통과학연구
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• 제15권12호
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• pp.61-72
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• 2017

Purpose - Despite that the importance of small enterprises' performance in the community has been magnified, no study has been conducted yet on the performance based on consumers directly faced by small enterprises. Accordingly, this study aims to investigate the relationship between the life styles of consumers who use small enterprises' stores by type and the word of mouth(WOM) effects, which are concrete behaviors of consumers. Research design, data, and methodology - The VALS classification system was utilized to classify the types of life styles of consumers who use small enterprises' stores. The consumers were divided into a total of four types. This study was intended to investigate the effects of the types of consumers on the word of mouth(WOM) effects of consumers who use small enterprises' stores along with the effects of consumers' perception of economic situations on their word of mouth(WOM) effects after using small enterprises' stores. Results - The results of the study indicated that among the types of consumers who use small enterprises' stores, the group that pursues faith and the group that pursues knowledge had positive (+) effects on favorable word of mouth(WOM) effects. However, the group that pursues trends and the group that pursues action were shown to have no effect and positive or negative perceptions of economic situations were shown to have no effects of the word of mouth(WOM) effects of users of small enterprises' stores. Conclusions - In this study, as a measure to create small enterprises' performance, word of mouth(WOM) effects on small enterprises' stores according to consumers' consumption behaviors were examined focusing on consumers. Through the study results, the groups of consumers who use small enterprises' stores by type that provide favorable word of mouth(WOM) effects were derived. And This Study aims to investigate the relationship between the four type life styles of consumer who use small enterprises' stores and the word of mouth(WOM) effect. Accordingly This study is significant in that it derived a measure to create small enterprises' performance centering on consumers and that it presented a cornerstone for the establishment of small enterprises at the government level.

• 만화애니메이션 연구
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• 통권31호
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• pp.209-226
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• 2013

멀티미디어 환경의 급격하고 다양한 예술적 변화와 함께 사회 인프라의 디지털 첨단화로 문화콘텐츠를 기반으로 하는 도시환경 건설이 활성화되고 있다. 최근 급속도로 늘어나고 있는 미디어 파사드(Media Facade)라 표현되는 도시 건축물 전면의 대형 영상이미지들은 이제 전혀 새로운 것이 아니다. 또한 도시 공간속에 녹아든 IT 기술은 이제 건축과의 만남을 통하여 새로운 미디어로서의 가능성을 시험하고 있다. 하지만, 이와 같이 인프라적 확산과는 다르게, 미디어 파사드에 대한 정의가 불분명하여 야간의 경관조명이나 옥외 영상광고 정도의 수준에서 제도가 구축되었다. 이러한 가이드라인은 미디어 표현의 다양한 시각적 예술성 표현의 가능성 보다는 부정적 측면에서의 규제를 목적으로 하고 있어 미디어 파사드의 본질적 개념을 살리지 못하고 있는 실정이다. 본 논문은 미디어 파사드의 뉴미디어적 측면에서의 의미를 찾아 도시 캔버스화라는 매체적 차원에서 의미를 분석한다. 이에 따라 미디어와 파사드의 각각의 사전적 정의를 조사하여 미디어파사드의 본질적 정의는 무엇인지 문헌을 통해 새롭게 정의되도록 연구를 시도하였다. 이 과정에 미디어파사드 라는 용어는 한.중.일 3개국에서만 통용되고 서구권 나라들에서는 미디어아트의 한 분야로 인식되고 있다는 사실을 알게 되었다. 결국 미디어파사드는 경관조명 차원에서 기술적으로 분류되기 위한 목적이 강하며, 학술적으로 명확히 규명되지 않는 용어이다. 예술분야에서 바라보는 미디어 파사드는 신 매체적 차원에서 미디어아트의 한 분야로 보는 것이 바람직하다는 결론에 도달하게 되었다. 본 연구를 통해 향후 도시 미디어파사드 정책에 대한 올바른 가이드라인이 구축되어야 할 것으로 보며, 이 가이드라인을 통해 무분별한 조명연출이 아닌 도시의 캔버스화라는 개념에서 예술적 평가가 이루어져야 할 것이다.

• 한국항행학회논문지
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• 제24권2호
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• pp.85-91
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• 2020

최근 다양한 환경에서 무인기를 효율적으로 운용하기 위한 목적으로 멀티모드 레이다 시스템이 고안되었으며, 이는 PD (pulse Doppler) 방식과 FMCW (frequency modulated continuous wave) 방식을 통합하여 활용할 수 있다는 장점을 가진다. 멀티모드 레이다 시스템의 하드웨어 구조의 경우 FFT (fast Fourier transform) 프로세서와 IFFT (inverse fast Fourier transform) 프로세서가 필수적이지만, FFT 프로세서는 큰 복잡도를 갖는 구조 중 하나로 FFT 프로세서의 복잡도를 감소시키는 방향으로의 구조 설계가 필요하다. 또한, 다양한 거리 해상도를 요구하는 레이다 응용 환경을 고려했을 때, FFT 프로세서는 가변 길이의 연산을 지원할 필요가 있다. 이에 본 논문에서는 멀티모드 레이다 신호처리 프로세서 거리 추정부의 FFT 프로세서와 IFFT 프로세서를 16~1024 포인트의 가변 길이 연산을 지원하는 단일 FFT 프로세서의 하드웨어로 설계하여 제안한다. 제안된 FFT 프로세서는 MATLAB 기반 알고리즘 설계를 수행한 뒤, 그 결과를 토대로 Verilog-HDL (hardware description language)을 활용하여 RTL (register transfer level) 설계가 수행되었으며, 논리 합성 결과 총 총 7,452개의 logic elements, 5,116개의 registers로 구현 가능함을 확인하였다.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제1권3호
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• pp.159-168
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• 2012

SNS, 클라우드, Web3.0과 같은 새로운 IT환경은 '관계(relation)'가 중요한 요소가 되고 있다. 그리고 이들 관계(relation)는 거래, 즉, 트랜잭션을 발생시킨다. 그러나 우리가 사용하고 있는 관계형 데이터베이스(RDBMS)나 그래프 데이터베이스는 관계(relation)를 나타내는 그래프 구조와 트랜잭션을 동시에 처리하지 못한다. 본 논문은 확장 가능한 복잡 네트워크 시스템에서 활용할 수 있는 그래프 구조와 트랜잭션을 동시에 처리할 수 있는 방법을 제안한다. 제안 기법은 토픽맵의 데이터 모델을 응용하여 그래프 구조와 트랜잭션을 동시에 저장하고 탐색한다. 토픽맵은 시멘틱 웹(Web3.0)을 구현하는 온톨로지 언어 중 하나로써, 정보자원들 사이의 연관 '관계(relation)'를 통해 정보의 네비게이터로써 활용되고 있다. 또한 본 논문에서는 컬럼형 데이터베이스인 카산드라를 이용하여 제안 기법의 아키텍처를 설계, 구현하였다. 이는 분산처리를 이용하여 빅데이터 레벨의 데이터까지 처리할 수 있도록 하기 위함이다. 마지막으로 대표적인 RDBMS인 오라클과 제안 기법을 동일한 데이터 소스, 동일한 질문에 대해 저장 및 질의를 하는 과정을 실험으로 보였다. 이는 조인(join) 없이 관계(relation)를 표현함으로써 RDBMS의 역할까지 충분히 대체 가능함을 보이고자 한다.