• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.430.2-430.2
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• 2014

Previous studies to enhance optical properties of opto-electronic devices involve patterning of inorganic materials. Patterning of inorganic material usually encompasses vacuum process that hinders productivity and increases cost. In this research, we successfully formed nano patterns with polymer matrix and fabricated photonic crystals. This process is anticipated to increase the performance of opto-electronic devices without any vacuum process. Moreover, nano imprint technology reduces cost and bolsters productivity.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.556-559
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• 2002

We designed a low cost optical structure of transflective LCD that uses only a half number of retardation films compared to general active matrix transflective LCD. The prototype embodied by this design shows reasonable reflective and transmissive performance. This design would provide us thinner, lighter and cheaper product due to its reduced retardation film structure.

• Journal of the Korean Operations Research and Management Science Society
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• v.19 no.1
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• pp.145-152
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• 1994

This paper deals with an economic design of acelerated life test under constant stresses where failure times are exponentially distributed. In this case the optimization criterion is the information amount per unit cost. Fisher's information matrix of exponential distribution's parameters and expected cost considering fixed and variable costs are obtained. The decision variable is the censoring time in the model. In the 2-level constant stress case, it is proved that the optimal solution exists and is unique under some condition. Numerical examples are also included.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.04a
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• pp.1-7
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• 2001

This paper presents product level considerations for multichip packaging as a cost effective alternative to single chip packaging in the design and manufacture of mobile telephony products. Important aspects include component functionality and complexity, acquisition and logistics costs, product modularity and integration. Multichip packaging offers unique solutions and significant system level cost savings in many applications including RF modules, digital matrix functions and product options such as security, data storage, voice recognition, etc.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.3 no.3
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• pp.55-58
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• 1980

Today, L.P. model has often been used in solving economic and managemental phenomena. But in case of adopting L.P. model in dealing with practical economic and managemental problems there is a possibility that we have difficulties in solving these problems because of greatness of model size, cost for collecting data, cost for adjusting matrix, and etc. In this respect "Decomposition Algorithm for L.P." has been used in overcoming the difficulties above stated. In this paper therefore, I will try to introduce and them criticize Dantzig -Wolfe's "Decomposition Method" and Kornai - Liptak's "Two - Level Planning".ot;Two - Level Planning".uot;.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.11
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• pp.3030-3049
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• 2023

With the development and wide application of hybrid network computing modes like cloud computing, edge computing and fog computing, the customer service requests and the collaborative optimization of various computing resources face huge challenges. Considering the characteristics of network environment resources, the optimized deployment of service resources is a feasible solution. So, in this paper, the optimal goals for deploying service resources are customer experience and service cost. The focus is on the system impact of deploying services on load, fault tolerance, service cost, and quality of service (QoS). Therefore, the alternate node filtering algorithm (ANF) and the adjustment factor of cost matrix are proposed in this paper to enhance the system service performance without changing the minimum total service cost, and corresponding theoretical proof has been provided. In addition, for improving the fault tolerance of system, the alternate node preference factor and algorithm (ANP) are presented, which can effectively reduce the probability of data copy loss, based on which an improved cost-efficient replica deployment strategy named ICERD is given. Finally, by simulating the random occurrence of cloud node failures in the experiments and comparing the ICERD strategy with representative strategies, it has been validated that the ICERD strategy proposed in this paper not only effectively reduces customer access latency, meets customers' QoS requests, and improves system service quality, but also maintains the load balancing of the entire system, reduces service cost, enhances system fault tolerance, which further confirm the effectiveness and reliability of the ICERD strategy.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.3
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• pp.458-465
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• 2008

In this paper, we propose a non-fragile guaranteed cost controller design method for uncertain linear systems with constant delyas in state. The norm bounded and time-varying uncertainties are subjected to system and controller design matrices. A quadratic cost function is considered as the performance measure for the system. Based on the Lyapunov method, an LMI(Linear Matrix Inequality) optimization problem is established to design the controller which uses information of delayed state and minimizes the upper bound of the quadratic cost function for all admissible system uncertainties and controller gain variations. Numerical examples show the effectiveness of the proposed method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.10
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• pp.1393-1398
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• 2012

Due to environmental regulation and technical improvements, renewable energy sources (RES) are increasingly penetrated and operated in power systems. Clean energy technologies have become cost-competitive with conventional power systems, and in the near future, the generation cost of RES is expected to approach grid parity. In this situation, it should be considered an extraordinarily important issue to be maximized resulting in utilization of RES as well as to develop technologies for efficiency improvement of RES. Therefore, in this paper, the method for determining an optimal installed capacity and interconnected location of RES is proposed in order to minimize the cost of energy not supplied, which can contribute to improve distribution reliability.

• Journal of Korean Institute of Industrial Engineers
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• v.30 no.3
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• pp.250-260
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• 2004

This study considers a linear connected-(r,s)-out-of-(m,n):F lattice system whose components are ordered like the elements of a linear (m,n )-matrix. We assume that all components are in the state 1 (operating) or 0 (failed) and identical and s-independent. The system fails whenever at least one connected (r,s)-submatrix of failed components occurs. The purpose of this paper is to present an optimization scheme that aims at minimizing the expected cost per unit time. To find the optimal threshold of maintenance intervention, we use a genetic algorithm for the cost optimization procedure. The expected cost per unit time is obtained by Monte Carlo simulation. The sensitivity analysis to the different cost parameters has also been made.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.359-360
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• 2016

This paper presents a new predictive current control (PCC) method to achieve the coordinate control of power and current of the matrix converter under unbalanced input voltages. In order to control the power fluctuation in the input side, the flexible source current reference is generated based on the positive-negative sequence components of the input voltage. The optimal switching state to adjust source and load currents is selected by minimization the cost function which is obtained from the sum of the absolute errors between the current references and their predictive values. Simulation results are given to validate the effectiveness of the proposed PCC method.