• Communications for Statistical Applications and Methods
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• v.15 no.5
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• pp.753-764
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• 2008

The $L_1$ regularized estimator in quantile problems conduct parameter estimation and model selection simultaneously and have been shown to enjoy nice performance. However, $L_1$ regularized estimator has a drawback: when there are several highly correlated variables, it tends to pick only a few of them. To make up for it, the proposed method adopts doubly regularized framework with the mixture of $L_1$ and $L_2$ norms. As a result, the proposed method can select significant variables and encourage the highly correlated variables to be selected together. One of the most appealing features of the new algorithm is to construct the entire solution path of doubly regularized quantile estimator. From simulations and real data analysis, we investigate its performance.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.11a
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• pp.403-408
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• 2005

다단계 호핑(multi-hop) 무선 센서네트워크의 라우팅 경로를 설정하는데 있어서 데이터 전송의 요구가 있는 경우에만 경로를 만드는 Demand-Driven 방식의 대표적인 방법이 DSR(Dynamic Source Routing)인데 라우트 레코드를 패킷에 실어 보내기 때문에 이 또한 센서노드들의 수가 많아질수록 패킷이 무거워질 수밖에 없다. 본 논문에서는 DSR 프로토콜을 기반 하면서도 라우팅 테이블을 적절히 이용하여 노드 수 증가에 대해 고정된 패킷크기를 가지도록 하였으며 라우팅 비용함수를 적용하여 각 센서노드들의 전원 소모량, 이동성(Mobility), 네트워크 내에서의 Traffic, 거리(Hop) 등을 복합적으로 고려한 안정적이고 신뢰성 있는 최적의 라우팅 설정 알고리즘을 제안한다.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.1
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• pp.8-20
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• 1999

In this paper, a design and estimation procedure for the stochastically dependent nonstationary multiple acceptance sampling plans is developed. At first, the rough-cut acceptance and rejection numbers are given as an initial solution from the corresponding sequential sampling plan. A Monte-Carlo algorithm is used to find the acceptance and rejection probabilities of a lot. The conditional probability formula for a sample path is found. The acceptance and rejection probabilities are found when a decision boundary is given. Several decision criteria and the design procedure to select optimal plans are suggested. The formula for measuring performance of these sampling plans is developed. Type I and II error probabilities are also estimated. As a special case, by setting the stage size as 1 in a dependent sampling plan, a sequential sampling plan satisfying type I and II error probabilities is more accurate and a smaller average sample number can be found. In a numerical example, a Polya dependent process is examined. The sampling performances are shown to compare the selection scheme and the effect of the change of the dependency factor.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.278-282
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• 2010

모바일 애드혹 네트워크에서의 멀티패스 라우팅 프로토콜은 기존의 단일패스 라우팅 프로토콜에 비하여 대역폭을 효율적으로 사용할 수 있고 혼잡을 완화시킬 수 있으며, 데이터 전달의 신뢰성을 제공할 수 있다. 하지만 멀티패스 라우팅 프로토콜에서의 경로 탐색 과정은 오버헤드가 크고 계산의 복잡도 또한 높다. 본 논문에서는 무선 애드혹 네트워크에서의 멀티패스 라우팅을 위한 효율적인 노드디스조인트 경로 탐색 알고리즘을 제안한다. 제안하는 알고리즘은 지연된 RREP(Route Reply) 패킷을 사용하여 최적의 노드 디스조인트 경로를 탐색하고 그중 간섭 및 충돌의 영향이 적은 경로 집합을 선택한다. 이를 통해 빠르게 트래픽을 분산시킬 수 있고 충돌로 인한 오류의 발생을 낮추어 신뢰성을 높일 수 있다. 실험을 통하여 제안하는 경로 탐색 알고리즘이 최적의 멀티패스를 선택함을 확인하였다.

• Journal of the Korea Society for Simulation
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• v.8 no.3
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• pp.67-76
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• 1999

The study of the optimization of operating policy of AGV system, which is used in many factory automation environments has been proceeded by many researchers. The major operating policy of AGV system consists of routing and scheduling policy. AGV routing is composed with collision avoidance and minimal cost path find algorithm. To allocate jobs to the AGV system, AGV scheduling has to include AGV selection rules, parking rules, and recharging rules. Also in these rules, the key time parameters such as processing time of the device, loading/unloading time and charging time should be considered. In this research, we compare and analyze several operating policies of multiple loop-multiple AGV system by making a computer model and simulating it to present an appropriate operating policy.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.16-29
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• 1993

The objective of this research is in the development of a flexible 3-dimensional inspection system for the sculptured surface by integrating the Coordinate Measuring Machine (CMM), CAD database, and vision system. To achieve the proposed flexible inspection system, two research categories are discussed in the study: new inspection planning method includes a new measuring point selection method and various new probe path generation methods. The object recognition and localization process for the unknown surface can be easily carried out by introducing a new concept called "Z-Layer". The experimental results indicate that the developed flexible inspection system, with the proposed algorithm, can be inplemented in real situation.situation.

• The KIPS Transactions:PartD
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• v.13D no.7 s.110
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• pp.923-930
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• 2006

In this paper we design the system test model for the weapon system embedded software based on the Time Factor Method(TFM) considering time factors and suggest the results through the case study. For doing this, we discuss the features, system tests and the object-oriented model based UML notations of the weapon system embedded software. And we give a test method considering time factors, a measuring method to time factors, and a test case selection algorithm as an approach to the TFM for designing the system test model. The TFM based system test model consists of three factors (X, Y, Z) in the weapon system embedded software. With this model, we can extract test cases through the selection algorithm for a maximum time path in 'X', identify the objects related to the Sequence Diagram in 'Y' and measure the execution time of each objects which is identified by the Timing Diagram in 'Z' Also, we present the method of extracting the system test cases by applying the proposed system test model to the 'Multi-function missile defense system'.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.8
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• pp.17-25
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• 1998

Aluminum alloys have low density, relatively high strength and yield strength, good plasticity, good machinability, and high corrosion and acid resistance. Therefore, they are suitable for large containers for the food, chemical and other industries. Large containers are often bodies of revolution consisting of shell courses, stiffening rings, heads and other elements joined by annular welds. Larger containers have longer welds and require greater leak-tightness and higher weld mechanical properties. The LNG tank consists of aluminum plates with various sizes, so its construction should by divided by several sections. Moreover, each section has its own sub-section consisted of several aluminum plates. To guarantee the quality of huge LNG tank, therefore, the precise control of plate dimension should by urgently needed in conjunction with the appropriate selection of process parameters such as cutting speed, depth of cut, rotational speed and so on. In this paper, a manufacturing system was developed to implement automatic circular tracking in height direction and automatic circular interpolation in depth of cut direction. Also, the neural network based on the backpropagation algorithm was used to predict the cutting quality and motor load related with the life time of the developed system. It was revealed that the manufacturing system and the neural network could be effectively applied to the bevelling process and to predict the quality of machined area and the motor load.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.2
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• pp.343-351
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• 2008

In this paper, we investigate the design of the QAM(Quadrature Amplitude Modulation) method for the CACB(Constant Amplitude Coded Multicode Biorthogonal) scheme. The modulation method fan improve the transmission data rate by increasing the BE(Bandwidth Efficiency). Additionally, we can improve the system performance by using the QAM SD(Soft Decision) method with the MDSA(Minimum Distance Selection Algorithm). Finally, the DFE(Decision Feedback Equalizer) for the CACB-QAM is simulated under the MPF(MultiPath Fading) channel for real implementation. The proposed scheme can be used for the PHY(PHYsical layer) standard of the WPAN(Wireless Personal Area Network) requiring high rate data transmission.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.10 s.113
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• pp.985-992
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• 2006

The classic routing algorithms try to minimize the number of hops to reach a destination. In our DPC(Distributed Power Control) this hop-by-hop power level selection is also used to select the path guaranteeing low energy consumption. The main goal is to realize a dynamic protocol able to be aware of mobility and to automatically set security threshold in order to get the best performance in every situation. In conclusion, the simulation DPC has improved energy gain of the AMRIS routing algorithm at the narrow area, and ODMRP routing algorithm has improved energy gain at the wide area.