• 영어어문교육
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• 제12권2호
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• pp.61-85
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• 2006

The purpose of the present study is to compare Korean EFL learners' speech corpus (i.e. oral productions) with their composition corpus (i.e. written productions). Four college students participated in the study. The composition corpus was collected through a writing assignment, and the speech corpus was gathered by audio-taping their oral presentations. The results of the data analysis indicate that (i) As for error frequency, young adult low-intermediate Korean EFL learners showed high frequency in determiners (mostly, indefinite articles), vocabulary (mostly, semantic errors), and prepositions. The frequency order did not show much difference between the speech corpus and the composition corpus; and (ii) When comparing the oral productions with the written productions, there were not many differences between them in terms of the contents, a style (i.e., colloquial vs. literary), vocabulary selection, and error types and frequency. Therefore, it is assumed that the proficiency in oral presentation of EFL learners at this learning stage heavily depends on how much/how well they are able to write. In other words, EFL learners' writing and speaking skills are closely co-related. It implies that the teacher does not need to separate teaching how to speak from teaching how to write. The teacher may use the same methods or strategies to help the learners improve their English speaking and writing skills. Furthermore, it will be more effective to teach writing before speaking since they have more opportunities to write than speak in the EFL contexts.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
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• pp.211-214
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• 2004

In railway system, the transportation plan corresponds to master plan for transport services. This service plan must be constructed to minimize operational cost or maximize revenue considering transportation demands and resource capacities in the operation company, and includes several sub-planning activities such as train operation frequency plan, train (schedule) plan, train capacity assignment plan, and rolling stock requirement plan. In this paper, we present profitability evaluation system for current transportation plan. The proposed system can be used for evaluating profitability by estimating train service revenue considering customer demands.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1538-1545
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• 2004

In the train schedule plan corresponds to a master plan for transport services. This service plan must be constructed to minimize operational cost or maximize revenue considering transportation demands and resource capacities in the operation company, and it includes several sub-planning activities such as train operation frequency plan, train schedule plan, train capacity assignment plan, and rolling stock requirement plan. In this paper, we present profitability evaluation system for the current train schedule plan. The proposed system can be used for evaluating profitability by estimating train service revenue considering customer demands.

• 한국간호교육학회지
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• 제20권4호
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• pp.628-638
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• 2014

Purpose: This study identifies the relation among the essentials of fundamental nursing skills performance (EFNSP), work capability and stress from work experienced by new clinical nurses. Method: This is a cross-sectional descriptive study with a self-reported questionnaire. The subjects were 224 new clinical nurses employed by general hospitals having more than 400 beds. The data, collected from February 10 to March 7, 2014, were analyzed using descriptive statistics, t-tests, ANCOVA, Pearson's correlation analysis and hierarchical linear regression. Results: The highest frequency of EFNSP of new clinical nurses was vital sign measurement (4.74, ${\pm}.89$) and the lowest frequency of performance was Basic CPR & defibrillator application (1.81, ${\pm}.94$). There were significant positive correlations between frequency and confidence of EFNSP (r=.64, p<.001), frequency and work capability (r=.34, p<.001), and confidence of EFNSP and work capability (r=.48, p<.001), but negative correlation stress from work and work capability (r=-.17, p=.009). General characteristics, stress from work, frequency and confidence in EFNSP and stress from work explain 25.1% of work capability. Conclusion: This result suggests the importance of EFNSP education in nursing schools and availability of opportunities to practice EFNSP during the post-graduation waiting period until assignment to a hospital.

• 한국시뮬레이션학회논문지
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• 제28권1호
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• pp.1-9
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• 2019

최근 물류창고의 중요성이 높아지고 있는 가운데 소량 다빈도 및 빠른 납품에 대응하기 위해 피킹 프로세스 개선에 많은 노력을 기울이고 있다. 본 연구는 개별오더 피킹 정책이 사용되는 상황에서 오더를 피커에게 할당하는 알고리즘을 제시한다. 이 알고리즘에서는 피킹과 관련된 피킹 처리시간, 오더 접수후 경과 시간, 검수/패킹 작업대 상황, 피커 오류, 고객 중요도의 다섯 개의 속성을 동시에 고려한다. 각 속성에 대한 측정값의 단위가 동일하도록 긴급도라는 척도를 도입한다. 긴급도의 값이 클수록 할당 우선순위를 높게 설정한다. 제안한 알고리즘에서는 각 속성의 가중치를 변경함으로써 피킹시스템의 운영목표에 따라 할당 정책을 유연하게 조정할 수 있도록 하였다. 가상의 축소된 물류창고를 대상으로 시뮬레이션 실험을 수행한 결과 시스템 쓰루풋과 흐름시간 측면에서 우수한 성능을 보였다.

• 전기전자학회논문지
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• 제16권3호
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• pp.258-264
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• 2012

주파수 선택적 페이딩 채널을 위한 선형 채널 추정 방식의 성능은 파일럿의 개수에 비례하므로 채널 추정의 정확도를 높이기 위해서 많은 파일럿을 쓰지 않을 수 없으며 필연적으로 전송 효율성이 낮아지는 단점이 있다. 또한 다중경로 채널의 희소(sparse)한 특성을 활용하지 않고 있다. 본 논문에서는 압축센싱 기법을 이용하여 아주 적은 수의 파일럿으로 희소한 채널을 추정하는 정합추구 기반 알고리듬과 간섭도(coherence)를 최소화하기 위한 파일럿 배치 방법을 제안한다. 또한 모의 실험을 통해 LS (least square) 채널 추정 방식보다 적은 수의 파일럿으로 우수한 채널 추정 성능을 보임을 확인한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.158-160
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• 2005

This paper presents a new approach to the problem of designing a cascaded three-parameters controller for a given linear time invariant (LTD plant in unity feedback system. We consider a proportional-integral-derivative (PID) and a first-order controller with specified overshoot and settling time. This problem is difficult to solve because there may be no analytical solution due to the use of low-order controller and furthermore. the zeros of controller just appear in the zeros of feedback system. The key idea of our method is to impose a constraint on the controller parameters so that the zeros of resulting controller are distant from the dominant pole of closed-loop system to the left as far as the given interval. Two methods realizing the idea are suggested. We have employed the characteristic ratio assignment (CRA) in order to deal with the time response specifications. It is noted that the proposed methods are accomplished only in parameter space. Several illustrative examples are given.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.4087-4102
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• 2014

Two-way relaying is an effective way of improving system spectral efficiency by making use of physical layer network coding. However, energy efficiency in OFDM-based bidirectional relaying with asymmetric traffic requirement has not been investigated. In this study, we focused on subcarrier transmission mode selection, bit loading, and power allocation in a multicarrier single amplified-and-forward relay system. In this scheme, each subcarrier can operate in two transmission modes: one-way relaying and two-way relaying. The problem is formulated as a mixed integer programming problem. We adopt a structural approximation optimization method that first decouples the original problem into two suboptimal problems with fixed subcarrier subsets and then finds the optimal subcarrier assignment subsets. Although the suboptimal problems are nonconvex, the results obtained for a single-tone system are used to transform them to convex problems. To find the optimal subcarrier assignment subsets, an iterative algorithm based on subcarrier ranking and matching is developed. Simulation results show that the proposed method can improve system performance compared with conventional methods. Some interesting insights are also obtained via simulation.

• Bulletin of the Korean Chemical Society
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• 제32권3호
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• pp.885-888
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• 2011

We report the first vibrational band assignment of imidazole trimer (IMT) solvated in helium nanodroplets. Several congested vibrational bands of imidazole (IM) clusters were obtained in the frequency region of $3513-3515\;cm^{-1}$ and vibrationally resolved due to the extremely low temperature (0.37 K) and very weak solutesolvent interaction environments of helium droplets. The unambiguous free NH band assignment was achieved with an aid of pick-up oven temperature dependence and vibrational transition moment angle (VTMA) experiments as well as density functional theory (DFT) calculations. The band at $3514.3\;cm^{-1}$ is attributed to the free NH stretching mode of linear IMT clusters, easily formed by the dipole-dipole interactions of IM in ultracold helium nanodroplets.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권1호
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• pp.20-23
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• 2006

This paper presents a new approach to the problem of designing a cascaded three-parameters controller for a given linear time invariant (LTI) plant in unity feedback system. We consider a proportional-integral-derivative (PID) and a first-order controller with the specified overshoot and settling time. This problem is difficult to solve because there may be no analytical solution due to the use of low-order controller. Furthermore, the zeros of controller just appear in the zeros of feedback system. The key idea of our method is to impose a constraint on the controller parameters so that the zeros of resulting controller are distant from the dominant pole of closed-loop system to the left as far as the given interval. Two methods realizing the idea are suggested. We have employed the characteristic ratio assignment (CRA) in order to deal with the time response specifications. It is noted that the proposed methods are accomplished only in parameter space. Several illustrative examples are given.