• 대한가정학회지
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• 제44권12호
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• pp.19-30
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• 2006

The present study investigated the effects of children's cognitive styles on their interpersonal problem solving performances. It examined closely whether children's interpersonal problem solving performances differed depending on their individual cognitive styles such as field independence-field dependence and reflection-impulse cognitive styles. It also examined whether children's interpersonal problem solving performances differed depending on the subjects children interacted with. The subjects were 80 5-and 6-year-old children from three child care centers. Collected data were analyzed with SPSS Win 10.0 and processed statistically using average, standard deviation, and repeated measures design. Children's interpersonal problem solving performances showed differed according to the subjects they interacted with. Children showed better interpersonal problem solving performances with their peers than with adults like teachers or parents. There was a significant positive correlation between children's field independence-field dependence cognitive styles and interpersonal problem solving performances. That is, the more independent children were, the higher their interpersonal problem solving performances were. In addition, there was a partially negative correlation between children's reflection-impulse cognitive styles and interpersonal problem solving performances. The more impulsive children were, the lower the problem solving performances were.

• 전기학회논문지
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• 제62권3호
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• pp.376-379
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• 2013

Multi-walled carbon nanotubes (MWCNTs) were synthesized using catalytic chemical vapor deposition (CVD) method. Oxygen plasma treatment was applied to modify surface state of the CNTs synthesized for improvement of field emission performance. Surface state of the plasma treated CNTs was studied by X-ray photoelectron spectroscopy (XPS). The surface states of the CNTs were changed as a function of plasma treatment time. The oxygen related carbon shift was moved toward higher binding energy with the plasma treatment time. This result implies that the oxygen plasma treatment changes the surface state effectively. While any shift in carbon 1s peak was not detected for the as grown CNTs, oxygen related carbon shift was detected for the plasma treated CNTs. Carbon shift implies that closed CNT tips were opened by the oxygen plasma and reacted with oxygen species. Since the field emission occurs at pentagons or dangling bonds of the CNT tips, the increase of carbon-oxygen bonds plays an important role in field emission behavior by increasing the number of electron emission sites resulting in improvement of the field emission performance.

• 대한전자공학회논문지SP
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• 제44권4호통권316호
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• pp.101-108
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• 2007

고성능 네트워크와 분산처리구조가 병렬처리와 함께 결합되면, 전체적인 디지털 신호처리 시스템의 계산능력, 신뢰도, 다양성을 향상시킨다. 본 논문에서는, 발전된 형태의 수중레이더 (sonar) 알고리즘인 수중정합장처리 (Matched-Field Processing MFP)를 위한 병렬처리 알고리즘을 디자인하고 다중 DSP 프로세서 기반의 병렬처리 시스템 상에서 성능분석과 함께 최적의 병렬처리 솔루션을 제안한다. 각각의 병렬 알고리즘은 특정한 도메인에서 주어진 계산량을 분산시키며 이를 통한 속도향상을 추구한다. 필요한 연산량과 형태에 따라서 병렬 알고리즘은 각기 다른 성능향상을 보여준다. 또한, 알고리즘의 계산량 분산방식 프로세서간의 통신방식, 알고리즘의 복잡도, 프로세서의 속도, 목적하는 시스템의 구성에 따라서 다양한 성능지표를 보여준다. 제안하는 주파수와 출력값 기반의 병렬 알고리즘은 상당한 계산량을 요구하는 수중정합처리 알고리즘을 적절히 다중 프로세서에 균형 있게 분산시켜 프로세서의 개수와 비례하는 성능향상을 보여주고 있다.

• 농업과학연구
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• 제44권1호
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• pp.114-122
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• 2017

An experimental pick-up type pulse crop harvester was built and its harvesting performance for green kernel black bean was evaluated. Field bean loss and harvested bean quality of the harvester were analyzed according to engine speeds of 2,000; 2,400; 2,800; 3,000; and 3,200 rpm, and travel speeds of 0.6; 1.0; and 1.4 m/s. Operating conditions and field capacity of the harvester for proper harvesting were estimated. The harvester had an optimum performance at a grain moisture content of 13.4%, an engine speed of 3,000 rpm, and a travel speed of 1.2 - 1.3 m/s. Subsequently, the picking-up, discharging, and total bean loss ratios were found to be 1.6, 1.3, and 2.9%, respectively. The whole bean, damaged bean, unthreshed bean, and foreign material ratios were determined to be 96.2, 1.0, 0.1, and 0.3%, respectively. Results showed that the harvester had lower bean loss and higher harvested bean quality than those of imported bean combines. The harvester could harvest 2 rows with a crop spacing of an approximately 1.4 m. Its optimum travel speed was estimated to be approximately 1.2 m/s when harvesting performance was taken into account using such variables as field bean loss and harvested bean quality for green kernel black bean. Effective field capacity of the harvester was estimated at approximately 40 a/h.

• 한국재난정보학회 논문집
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• 제9권1호
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• pp.22-29
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• 2013

중온 아스팔트 포장공법은 밀입도 아스팔트 포장공법 대비 생산 및 포설온도를 낮추어 생산 및 시공이 가능한 포장공법으로 연료 소모량과 온실가스 배출량 면에서 효과가 우수하다. 본 연구에서는 중온 개질 아스팔트 포장의 장기 현장 공용성을 평가하기 위하여 시험포장이 실시 된 구간에 대해 미끄럼 저항성, 소성변형, 평탄성과 같은 현장실험을 수행하였다. 현장실험 결과 미끄럼 저항성은 공용 20개월 후에도 공용초기와 같이 S1 위험도 1기준을 만족시켰으나 소성변형, 평탄성에서는 공용기간에 따라 다소 감소추세를 보였다. 그러나 현장실험이 수행된 구간은 버스정류장으로 중차량 통행량이 많고 중차량인 버스의 출발과 정지가 반복되는 가혹한 환경조건에 노출되어 있음을 고려하였을 때 소성변형, 평탄성의 감소추세는 수용할 수 있는 정도이다. 균열의 경우 공용 11개월 후에는 관찰되지 않았으나 공용 20개월 후 에는 미세한 균열이 발생한 것을 관찰 할 수 있었는데 이는 첨가된 섬유로 인해 혼합물의 균열 저항성이 향상된 것으로 판단된다.

• 농업과학연구
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• 제48권1호
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• pp.141-149
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• 2021

The cultivation area for domestic cabbage increased by 26.3% from 10,968 ha in 2019 to 13,854 ha in 2020, and among leafy vegetables, the cabbage cultivation area was 62%, and production was 78.9%. Demand for field crop production of cabbage, which has a relatively high-income level compared to rice farming, is increasing, and mechanization of the field operation is urgently needed due to the insufficient development of related farming machinery. In this study, a prototype fabrication and performance test of a tractor-attached cabbage collector was carried out. The transport section was divided into two parts, one for the feeding and transportation and the other for the screening and packaging to selectively collect cabbages in bulk bags or boxes. The length of the primary collecting conveyor was designed to meet the field conditions of the Korean cabbage cultivation standards so that six cultivation rows could be worked simultaneously. Power was controlled by a hydraulic transmission line of the tractor and was easily mounted onto the 3-point hitch links behind the tractor. When the performance was evaluated, the transfer rate, loss rate, damage rate, and work performance were 100, 0, 1.2%, and 1.9 h·10 a^-1. Final improvement and commercialization of the prototype would considerably contribute to the mechanization of harvesting cabbage, the main ingredient of Kimchi.

• 대한방사선기술학회지:방사선기술과학
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• 제5권1호
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• pp.71-75
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• 1982

• 한국초전도ㆍ저온공학회논문지
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• 제19권4호
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• pp.31-39
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• 2017

European R&D on designing their version of a DEMO fusion tokamak has recently resulted in the testing of a prototype $Nb_3Sn$ Cable-in-Conduit Conductor (CICC) for the DEMO TF coil. The characteristics and reported results of low temperature performance tests with the prototype CICC sample are compared with those from CICC samples incorporating other recent $Nb_3Sn$ cable designs. The EU-DEMO TF CICC prototype shows performance characteristics similar to that of the ITER CS CICC with short twist pitch. This is a first for a CICC sample that does not have a circular cross section. Assessment of its internal magnetostatic self-field suggests that a reduction in the internal self-field due to the rectangular geometry of the EU-DEMO TF CICC prototype compared to one with a circular geometry may have contributed to the performance characteristics showing current sharing temperature ($T_{cs}$) initially increase then stabilize with repeated electromagnetic loading, similarly to ITER CS CICC results. However, constraints on the internal self-field are not a sufficient condition for this $T_{cs}$ characteristic to occur.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2301-2309
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• 2018

In a field-oriented vector-controlled permanent magnet synchronous motor (PMSM) control system, the d-axis current control loop can offer a free degree of freedom which can be used to improve control performances. However, in the industry the desired d-axis current command is usually set as zero without using the free degree of freedom. This paper proposes a method to use the degree of freedom for control performance improvement. It is assumed that both the inner loop proportional-integral (PI) current controller and the q-axis outer loop PI speed controller are tuned by the well-known tuning rules. This paper gives an optimal d-axis reference current command generator such that some useful performance indexes are minimized and/or a tradeoff between conflicting performance criteria is made. This paper uses a differential evolution algorithm to autotune the parameter values of the optimal d-axis reference current command generator. This paper implements the proposed control system in real time on a Texas Instruments TMS320F28335 floating-point DSP. This paper also gives experimental results showing the practicality and feasibility of the proposed control system, along with simulation results.

• Ocean Systems Engineering
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• 제4권1호
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• pp.1-19
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• 2014

Hydrodynamic coefficients strongly affect the dynamic performance of autonomous underwater vehicles (AUVs). A novel kind of underwater vehicle (Heavier-than-water AUV) with higher density than water is presented, which is different from conventional ones. RANS method and overlapping grids are used to simulate the flow field around the vehicle. Lifts, drags and moments of different attack and drift angles in steady state are calculated. The hydrodynamic performances and how the forces change with the attitude are analyzed according to the flow field structure. The steady-state results using overlapping grid method are compared with those of software FLUENT and wind tunnel tests. The calculation results show that the overlapping grid method can well simulate the viscous flow field around the underwater vehicle. Overlapping grid skills have also been used to figure out the planar-motion-mechanism (PMM) problem of Heavier-than-water AUV and forecast its hydrodynamic performance, verifying its effectiveness in dealing with the dynamic problems, which would be quite helpful for design and control of Heavier-than-water AUV and other underwater vehicles.