• 한국생산제조학회지
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• 제22권6호
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• pp.921-930
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• 2013

From an economic perspective, an enterprise's business activity depends on the efficient use of corporate resources for generating profits. However, on the enterprise side, it is difficult to measure and evaluate the effective use of each resource. This paper suggests an alternative for eliminating process inefficiencies in the consolidation of competitive power in auto parts manufacturing company A. Multitudinous process variables from company A's raw materials-to-shipment process are configured as input resources, and a Data Envelopment Analysis(DEA) is carried out to determine economical benefit of said resources' operation, as well as how products are manufactured. The DEA model offers a non-parametric approach to measuring relative efficiency using input and output factors. Furthermore, AHP is used for logically deciding the importance of each evaluation factor. In general, DEA models have been used for measuring efficiency of the service and public sectors. However, this study focused on measuring the efficiency of SMEs production lines.

• 한국항행학회논문지
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• 제6권2호
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• pp.119-129
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• 2002

기동표적의 추적은 실제의 표적 궤적과 기동의 통계적 특성을 미리 알 수 없기 때문에 매우 어려운 일이다. 이를 해결하기 위한 여러 가지 기법들이 제안되었고 이들 방식은 과거의 고전적인 방법에 비해 상당한 성능향상을 가져왔다. 이들 중에서 많이 사용되고 있는 방법은 입력추정, 가변차원 및 회전가속도 추정기를 사용하는 필터이다. 이들에 대한 성능은 각각 해석되어 왔으나 비교 분석되지 않았다. 본 논문에서는 칼만필터를 기본으로 한 이들 필터에 대하여 추적 성능을 비교한다. 실제적인 기동표적의 추적에 용이하게 적용할 수 있도록 3가지 종류의 회전 기동에 대해 Monte-Carlo 시뮬레이션을 수행하고 그 결과를 비교 분석함으로써 각 필터에 대한 특성을 해석한다.

• 전자공학회논문지B
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• 제31B권9호
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• pp.159-165
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• 1994

In this paper, we propose a multi-layer associative neural network structure suitable for hardware implementaion with the function of performance refinement and improved robutst capability. Unlike other methods which reduce network complexity by putting restrictions on synaptic weithts, we are imposing a requirement of hidden layer neurons for the function. The proposed network has synaptic weights obtainted by Hebbian rule between adjacent layer's memory patterns such as Kosko's BAM. This network can be extended to arbitary multi-layer network trainable with Genetic algorithm for getting hidden layer memory patterns starting with initial random binary patterns. Learning is done to minimize newly defined network error. The newly defined error is composed of the errors at input, hidden, and output layers. After learning, we have bidirectional recall process for performance improvement of the network with one-shot recall. Experimental results carried out on pattern recognition problems demonstrate its performace according to the parameter which represets relative significance of the hidden layer error over the sum of input and output layer errors, show that the proposed model has much better performance than that of Kosko's bidirectional associative memory (BAM), and show the performance increment due to the bidirectionality in recall process.

• Ocean and Polar Research
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• 제32권4호
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• pp.489-499
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• 2010

The securing of raw material is an important requirement for economic development. Many countries, including Korea, actively seek out a stable supply of minerals such as manganese. Manganese nodules are rock concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core and include several strategic minerals necessary for economic development. In particular, the manganese nodule development project (MNDP) plays an important role in the Korean national economy. This study attempts to apply input-output (I-O) analysis in investigating the economic impacts of the MNDP in the Korean national economy. A static I-O framework was employed, focusing on four topics in its application; the production-inducing impacts, the value-added-inducing impacts, the employment-inducing impacts and R&D-inducing impacts of MNDP investments on other sectors. To this end, several versions of the demand-driven models are utilized. In addition, inter-industry linkage analysis is performed to obtain information on the forward and backward linkage effects of industries, including MNDP, to quantify the strength of causation among these industries.

• 한국수자원학회논문집
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• 제37권8호
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• pp.687-693
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• 2004

관측한 유역특성 자료와 지하수 유동 매개변수 값을 변화시키면서 MODFLOW 모형으로 시뮬레이션 한 결과를 비교ㆍ분석하였으며, 민감도 분석을 통하여 매개변수들의 상대적인 중요성을 파악하였다. 투수계수, 비산출율, 비저류계수, 대수층 두께 및 양수정 위치 등의 다양한 매개변수들에 대한 지속가능개발량 반응을 분석하였다. 매개변수에 대한 민감도 분석 결과, 하천에서 지하수체로 유입하는 량과 저류량은 비산출율과 대수층 두께에 민감하였으며, 지속가능개발량은 투수계수와 대수층 두께에 민감한 것으로 나타났다. 본 연구결과는 지역특성을 고려한 지하수 개발 및 관리계획 수립을 위한 기초자료로서 활용될 수 있을 것이다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.328-333
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• 2007

The purpose of this study is modelling of system air-conditioner for TRNSYS. System air-conditioner is operated by a variable capacity compressor and accommodated by multiple evaporators. By reason of these feature, realizing performance of system air-conditioner for TRNSYS was incomplete. In this study performance data of system air-conditioner and control logics are used to make system air-conditioner module for TRNSYS. Performance data contains total capacity, power input and capacity index of system air-conditioner. The simulation was carried out in a mode of temperature level control using TRNSYS 16. The simulation shows that the system air-conditioner model operate variable capacity and can compute capacity index and power input of system.

• 산업경영시스템학회지
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• 제36권3호
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• pp.126-132
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• 2013

In this paper, efficiencies of core technology development projects, conducted by Ministry of Trade, Industry and Energy, are compared. In the process, DEA (Data Envelopment Analysis) is utilized as a main technique for comparing efficiencies. For DEA, input oriented BCC Model is adopted with government grant, recipient expenditure, the number of participating institutions, and project duration as input factors, and the number of patents, the number of papers, and occurred sales as output factors. As a result, next generation mobile communication project turns out to be the most efficient project of all. Therefore, next generation mobile communication project should be benchmarked for the other projects to follow. However, these results should be used only for reference data since every project has a different objective and, of course, is run under a different environment.

• Journal of Power Electronics
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• 제17권4호
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• pp.991-1003
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• 2017

The conventional sliding mode control (CSMC) has a number of problems. It may cause dc output voltage ripple and it cannot guarantee the robustness of the whole system for a matrix rectifier (MR). Furthermore, the existence of a filter can decrease the input power factor (IPF). Therefore, a novel global sliding mode control (GSMC) based on a hyperbolic tangent function with IPF compensation for MRs is proposed in this paper. Firstly, due to the reachability and existence of the sliding mode, the condition of the matrix rectifier's robustness and chattering elimination is derived. Secondly, a global switching function is designed and the determination of the transient operation status is given. Then a SMC compensation strategy based on a DQ transformation model is applied to compensate the decreasing IPF. Finally, simulations and experiments are carried out to verify the correctness and effectiveness of the control algorithm. The obtained results show that compared with CSMC, applying the proposed GSMC based on a hyperbolic tangent function for matrix rectifiers can achieve a ripple-free output voltage with a unity IPF. In addition, the rectifier has an excellent robust performance at all times.

• Earthquakes and Structures
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• 제3권3_4호
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• pp.203-230
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• 2012

This paper presents results for impedance (and compliance) functions and input motions of foundations in a layered half-space computed on the basis of a procedure that combines a consistent transmitting boundary with continued-fraction absorbing boundary conditions which are accurate and effective in modeling wave propagation in various unbounded domains. The effects of obliquely incident seismic waves in a layered half-space are taken into account in the formulation of the transmitting boundary. Using the numerical model, impedance (and compliance) functions and input motions of rigid circular foundations on the surface of or embedded in a homogeneous half-space are computed and compared with available published results for verification of the procedure. Extrapolation methods are proposed to improve the performance in the very-low-frequency range and for the static condition. It is concluded from the applications that accurate analysis of foundation dynamics and soil-structure interaction in a layered half-space can be carried out using the enhanced consistent transmitting boundary and the proposed extrapolations.

• Smart Structures and Systems
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• 제24권2호
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• pp.257-266
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• 2019

The benefit of data fusion in improving the performance of Higher Order Sliding Mode (HOSM) observer is brought out in this paper. This improvement in the performance of HOSM observer, resulted in the improvement of active vibration control of a piezo actuated structure, when controlled by a Discrete Sliding Mode Controller (DSMC). The structure is embedded with two piezo sensors for measuring the first two vibrating modes. The fused output of sensors is applied to the HOSM observer for generating state estimates, these states generated are applied to the DSMC, designed for the fourth order linear time invariant model of the structure. In the simulation study, the structure is excited at the first and second mode resonance. It is found that better vibration suppression is obtained, when the states generated by the fused output of sensors is applied as controller input, than the vibration suppression obtained by applying the states generated by using individual sensor output. The closed loop performance of DSMC obtained with HOSM observer is compared with the closed loop performance obtained with the conventional observer. Results obtained shows that better vibration suppression is obtained when the states generated by HOSM observer is applied as controller input.