• 설비공학논문집
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• 제28권7호
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• pp.299-304
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• 2016

In recent years, heat source systems which have a principal effect on the performance of buildings are difficult to design optimally as a great number of design factors and constraints in large and complicated buildings need to be considered. On the other hand, it is necessary to design an optimum system combination and operation planning for energy efficiency considering Life Cycle Cost (LCC). This study suggests a multi-level and multi-objective optimization method to minimize both LCC and investment cost using a genetic algorithm targeting an office building which requires a large cooling load. The optimum method uses a two stage process to derive the system combination and the operation schedule by utilizing the input data of cooling and heating load profile and system performance characteristics calculated by dynamic energy simulation. The results were assessed by Pareto analysis and a number of Pareto optimal solutions were determined. Moreover, it was confirmed that the derived operation schedule was useful for operating the heat source systems efficiently against the building energy requirements. Consequently, the proposed optimization method is determined by a valid way if the design process is difficult to optimize.

• 한국군사과학기술학회지
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• 제1권1호
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• pp.114-127
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• 1998

A user friendly computer code(EMCOMST; Electro-Magnetic response for COMposite STructures) was developed which provides with computations of the response characteristics such as reflectance and transmittance to the incident wave angles, frequencies, composite thicknesses, ply orientations, and types of backplate as the linearly polarized transverse electro-magnetic wave is emitted to the advanced composite structures. In this investigation were reviewed the electromagnetic characteristics of the continuous orthotropic fiber-reinforced organic matrix composites with or without ferrite fillers, which are actively applied to low-weight and high-strength aircraft structures. Also were calculated the response of the three layered compound structures which have appropriately stacked above-mentioned materials as transmitting layer, absorbing layer, reflection layer, respectively under the specific thickness constraints for mechanical strength design requirements. For the composite structures presented in this study, minimum reflectance value less than -5㏈ can be obtained in the frequency range of 4 to 12 ㎓. In addition, analysis of structures attached isotropic radar absorbing materials(RAM) is facilitated by putting the material properties in the material input card entries adequately.

• 대한전기학회논문지
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• 제38권12호
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• pp.995-1006
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• 1989

로보트 매니퓰레이터가 컨베이어 상의 파트를 추적 하면서 작업을 수행하는 것은 작업 효율의 증가에 크게 기여한다. 본 논문은 컨베이어 상의 파트를 추적하기 위한 로보트 매니퓰레이터의 동작계획 알고리즘을 제안한다. 로보트 매니퓰레이터의 추적 동작은 밸트의 속도, 추적 시작 시간에서의 파트와 로보트 핸드의 위체이 의하여 결정된다. 이때 토크 및 관절 속도, 관절 가속도, 관절 저크의 제한범위가 모두 고려되며, 최소의 정착시간을 갖는 추적 궤적이 생성된다. 추적 해는 linearr quadratic tracking문제로 접근하여 구한다. 로보트매니퓰레이터의 동적 방정식은 파라메터의 함수 성능 지수를 최소화 하는 동적 방정식의 해는 동적 계획법에 의하여 구한다. ${\mu}-VAX_@$에 의한 시뮬레이션 결과를 제시한다.

• 대한임베디드공학회논문지
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• 제14권6호
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• pp.287-294
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• 2019

With the automation of production lines in the manufacturing industry, the importance of real-time fault diagnosis of facility is increasing. In this paper, we propose a fault diagnosis algorithm of LM (Linear Motion)-guide based on deep learning using vibration signals. Generally, in order to guarantee the performance of the deep learning, it is necessary to have a sufficient amount of data, but in a manufacturing industry, it is often difficult to obtain enough data due to physical and time constraints. To solve this problem, we propose a convolutional neural networks (CNN) model based on transfer learning. In addition, the spectrogram image is input to the CNN to reflect the frequency characteristic of the vibration signals with time. The performance of fault diagnosis according to various load condition and transfer learning method was compared and evaluated by experiments. The results showed that the proposed algorithm exhibited an excellent performance.

• ETRI Journal
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• 제38권2호
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• pp.280-290
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• 2016

To implement high-order multiuser multiple input and multiple output (MU-MIMO) for massive MIMO systems, there must be a feedback scheme that can warrant its performance with a limited signaling overhead. The interference-to-noise ratio can be a basis for a novel form of Codebook (CB)-based MU-MIMO feedback scheme. The objective of this paper is to verify such a scheme's performance under a practical system configuration with a 3D channel model in various radio environments. We evaluate the performance of various CB-based feedback schemes with different types of overhead reduction approaches, providing an experimental ground with which to optimize a CB-based MU-MIMO feedback scheme while identifying the design constraints for a massive MIMO system.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.923-928
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• 2003

This paper presents the motion control of a mobile robot with arc sensor for lattice type welding. Its dynamic equation and motion control method for welding speed and seam tracking are described. The motion control is realized in the view of keeping constant welding speed and precise target line even though the robot is driven along a straight line or comer. The mobile robot is modeled based on Lagrange equation under nonholonomic constraints and the model is represented in state space form. The motion control of the mobile robot is separated into three driving motions of straight locomotion, turning locomotion and torch slider controls. For the torch slider control, the proportional integral derivative (PID) control method is used. For the straight locomotion, a concept of decoupling method between input and output is adopted and for the turning locomotion, the turning speed is controlled according to the angular velocity value at each point of the comer with range of $90^{\circ}$ constrained to the welding speed. The proposed control methods are proved through simulation results and the results have proved that the mobile robot has enough ability to apply the lattice type welding line.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.315-320
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• 2009

Thermoeconomics or exergoeconomics can be classified into the three fields of cost estimating, cost optimization, and internal cost analysis. The objective of cost estimating is to estimate each unit cost of product and allocate each cost flow of product such as electricity or hot water. The objective of optimization is to minimize the input costs of capital and energy resource or maximize the output costs of products under the given constraints. The objective of internal cost analysis is to find out the cost formation process and calculate the amount of cost flow at each state, each component, and overall system. In this study, a new thermoeconomic methodology was proposed in the three fields. The proposed methodology is very simple and obvious. That is, the equation is only each one, and there are no auxiliary equations. Any energy including enthalpy and exergy can be applied and evaluated by this equation. As a new field, the cost allocation methodology on cool air or hot air produced from an air-condition system was proposed. Extending this concept, the proposed methodology can be applied to any complex system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권3호
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• pp.1016-1033
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• 2016

In this paper, we present a joint relay-and-antenna selection and power allocation strategy for multiple-input multi-output (MIMO) amplify-and-forward (AF) two-way relay networks (TWRNs). In our approach, we select the best transmit and receive antennas at the two sources, a best relay and a best transmit and receive antenna at the selected relay based on maximizing the minimum of the end-to-end received signal-to-noise-ratios (SNRs) under a total transmit power constraints. We obtained the closed-form solution for the optimal power allocation firstly. Then with the optimal allocation solution we found, we can reduce the joint relay-and-antenna selection to a simpler problem. Besides, the overall outage probability is investigated and a tight closed-form approximation is derived, which provides a method to evaluate the outage performance easily and fast. Simulation results are presented to verify the analysis.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권3호
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• pp.576-599
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• 2013

Protocol reverse engineering is useful for many security applications, including intelligent fuzzing, intrusion detection and fingerprint generation. Since manual reverse engineering is a time-consuming and tedious process, a number of automatic techniques have been proposed. However, the accuracy of these techniques is limited due to the complexity of binary instructions, and the derived formats have missed constraints that are critical for security applications. In this paper, we propose a new approach for protocol format extraction. Our approach reasons about only the evaluation behavior of a program on the input message from concolic execution, and enables field identification and constraint inference with high accuracy. Moreover, it performs binary analysis with low complexity by reducing modern instruction sets to BIL, a small, well-specified and architecture-independent language. We have implemented our approach into a system called Icefex and evaluated it over real-world implementations of DNS, eDonkey, FTP, HTTP and McAfee ePO protocols. Experimental results show that our approach is more accurate and effective at extracting protocol formats than other approaches.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.481-486
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• 2007

물 공급 지장의 경제적 파급 효과를 분석하기 위해 한국은행이 2007년 발간한 2003년 지역산업연관모형을 이용하였다. 특히 가뭄의 발생은 지역적인 특성을 가지고 있어서 지역에 따라 피해도 다르게 나타날 것이다. 우선적으로 배분해야할 각 산업의 순위도 지역별로 달라지게 될 것이다. 따라서 전국산업연관표를 이용하여 물 공급의 지장비용을 분석하였을 때보다 구체적으로 효율적인 물 배분에 대한 정보를 제공할 수 것이다. 특히 기존에는 지역별 물 공급 지장 비용을 계측하기 위하여 주로 전국산업연관표 이용하여 각 지역별 산업연관표를 간접 추계하여 사용하였다. 이 방식은 방법론에 따른 오차 존재 가능성이 크기 때문에 신뢰도가 결여된다. 그러나 본 연구는 한국은행의 2003년 실측(survey-based method) 지역산업연관표를 이용하였기 때문에 기존 연구보다 신뢰성있는 연구가 될 것이다. 추정결과, 우리나라 수도산업의 특징은 지역내 파급 효과가 지역간 파급 효과보다 큰 자급자족형 산업인 것으로 나타났다. 전후방연쇄효과도 거의 모든 지역에서 1이상으로 나타났고 후방연쇄효과가 가장 큰 지역은 경남지역으로 나타났다. 서울권과 경남권에서 만 원어치만큼 물 공급되지 않을 경우 해당 지역의 산업에 각각 130만 원과 57만 원의 피해 비용이 발생한다.