• Journal of the Korean Geotechnical Society
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• v.27 no.8
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• pp.51-61
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• 2011

Spatial estimation of the thickness and depth of the geological profile has been regarded as an important procedure for the design of soft ground. A minimum variance criterion, which has often been used in traditional kriging techniques, does not always guarantee the optima1 estimates for the decision-making process in geotechnical engineering. In this study, a geostatistica; framework is used to determine the optimal thickness of the consolidation layer and the optimal area that needs the adoption of prefabricated vertical drains via indicator kriging and loss function. From the exemplary problem, different optimal estimates can be obtained depending on the loss function chosen. The design procedure and method considering the minimum expected loss presented in this paper can be used in the decision-making process for geotechnical engineering design.

• Structural Engineering and Mechanics
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• v.71 no.1
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• pp.1-12
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• 2019

This study investigates optimum designs of steel space truss towers under seismic loading by using Jaya optimization algorithm. Turkish Earthquake Code (2007) specifications are applied on optimum designs of steel space truss towers under the seismic loading for different local site classes depending on different soil groups. The proposed novel algorithm does not have any algorithm-specific control parameters and depends only a simple revision equation. Therefore, it provides a practical solution for structural optimization problems. Optimum solutions of the different steel truss examples are carried out by selecting suitable W sections taken from American Institute of Steel Construction (AISC). In order to obtain optimum solutions, a computer program is coded in MATLAB in corporated with SAP2000-OAPI (Open Application Programming Interface). The stress and displacement constraints are applied on the design problems according to AISC-ASD (Allowable Stress Design) specifications. Firstly, a benchmark truss problem is examined to see the efficiency of Jaya optimization algorithm. Then, two different multi-element truss towers previously solved with other methods without seismic loading in literature are designed by the proposed algorithm. The first space tower is a 582-member space truss with the height of 80 m and the second space tower is a 942-member space truss of about 95 m height. The minimum optimum designs obtained with this novel algorithm for the case without seismic loading are lighter than the ones previously attained in the literature studies. The results obtained in the study show that Jaya algorithm is a practical and robust optimization method for structural optimization problems. Moreover, incorporation of the seismic loading causes significant increase in the minimum design weight.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.679-682
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• 2003

In this paper, we propose a Genetic Algorithm (GA) using symbiotic evolutionary viruses. Our GA is based on both the building block hypothesis and the virus theory of evolution. The proposed GA aims to control a destruction of building blocks by discovering, keeping, and propagating of building blocks based on virus operation. Concretely, we prepare the group of individuals and the group of viruses. In our GA, the group of individuals searches solutions and the group of viruses searches building blocks. These searches done based on the symbiotic relation of both groups. Also, our GA has two types of virus evaluation techniques. One is that each virus is evaluated by the difference of the fitness of an individual between before and after infection of virus. Another is that all viruses aye evaluated by the difference of the fitness of an individual between before and after infection of all viruses. Furthermore, we applied the proposed GA to the minimum value search problem of a test function which has some local solutions far from the optimal solution. And, we discuss a difference of behaviors of the proposed GA based on each virus evaluation techniques.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.4
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• pp.507-512
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• 2015

In the wireless localization systems using range measurements, iteration method-based approximated solutions have been used. Also, linear closed-form solutions have been investigated in the light of local minimum problem and computational load. However, each closed-form solution has individual error factors that cause usage limit of the solutions. In this paper, a fusion method integrating two representative closed-form solutions is presented. The presented method cancels the error factors of each solution out. Weights for integrating the standalone solutions are determined using the error factors-based fuzzy method. The performance of the proposed method is verified using some simulation results.

• Journal of Korean Society of Transportation
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• v.17 no.5
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• pp.111-122
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• 1999

A service network design model for LTL freight transportation is formulated as a mixed integer Programming Problem with two heuristic solution a1gorithms. The Proposed model derives the transportation Path for each origination-destination pair, taking into account transportation cost over the links and handling costs over the nodes. The first algorithm searches for a local minimum solution from a given initial solution by improving the quality of solution repeatedly while the second a1gorithm searches for a better solution using Simulated Annealing Method. For both solution algorithms, the initial solution is derived by a modified reverse Diikstras shortest Path a1gorithm. An illustrative example, Presented in the last part of the Paper, shows that the proposed algorithms find solutions which reduce the cost by 12% and 15% respectively, compared to the initial solution.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.7
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• pp.633-639
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• 2013

Several estimation methods used in the range measurement based wireless localization area have individual problems. These problems may not occur according to certain application areas. However, these problems may give rise to serious problems in particular applications. In this paper, three methods, ILS (Iterative Least Squares), DS (Direct Solution), and DSRM (Difference of Squared Range Measurements) methods are considered. Problems that can occur in these methods are defined and a simple hybrid solution is presented to solve them. The ILS method is the most frequently used method in wireless localization and has local minimum problems and a large computational burden compared with closed-form solutions. The DS method requires less processing time than the ILS method. However, a solution for this method may include a complex number caused by the relations between the location of reference nodes and range measurement errors. In the near-field region of the complex solution, large estimation errors occur. In the DSRM method, large measurement errors occur when the mobile node is far from the reference nodes due to the combination of range measurement error and range data. This creates the problem of large localization errors. In this paper, these problems are defined and a hybrid localization method is presented to avoid them by integrating the DS and DSRM methods. The defined problems are confirmed and the performance of the presented method is verified by a Monte-Carlo simulation.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.6
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• pp.25-32
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• 2004

We propose a hierarchical disparity estimation algorithm with edge-preserving energy-based regularization. Initial disparity vectors are obtained from downsampled stereo images using a feature-based region-dividing disparity estimation technique. Dense disparities are estimated from these initial vectors with shape-adaptive windows in full resolution images. Finally, the vector fields are regularized with the minimization of the energy functional which considers both fidelity and smoothness of the fields. The first two steps provide highly reliable disparity vectors, so that local minimum problem can be avoided in regularization step. The proposed algorithm generates accurate disparity map which is smooth inside objects while preserving its discontinuities in boundaries. Experimental results are presented to illustrate the capabilities of the proposed disparity estimation technique.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.2
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• pp.33-43
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• 2012

Digital signage is referred to as a smart electronic display system that delivers multimedia-based information and advertisements to customers. Typically, the digital signage starts its playback after downloading a list of multimedia contents from network storage to its local disk. However, a way of downloading the entire contents before its playback entails a long initial delay time. In this paper, we formulate a problem of the initial delay time and provide a solution to compute a minimally demanded initial delay time according to a given network bandwidth and qualities/sizes of the multimedia contents. In addition, we analyze the performance of the proposed solution with various multimedia contents on digital signage.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.9
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• pp.365-375
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• 2006

This paper is presented by the application of parallel adaptive evolutionary algorithm(PAEA) to search an optimal solution of a thermal unit commitment problem. The adaptive evolutionary algorithm(AEA) takes the merits of both a genetic algorithm(GA) and an evolution strategy(ES) in an adaptive manner to use the global search capability of GA and the local search capability of ES. To reduce the execution time of AEA, the developed algorithm is implemented on an parallel computer which is composed of 16 processors. To handle the constraints efficiently and to apply to Parallel adaptive evolutionary algorithm(PAEA), the states of thermal unit are represented by means of real-valued strings that display continuous terms of on/off state of generating units and are involved in their minimum up and down time constraints. And the violation of other constraints are handled by repairing operator. The procedure is applied to the $10{\sim}100$ thermal unit systems, and the results show capabilities of the PAEA.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.04a
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• pp.410-420
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• 2008

The progress of industrialization in Korea has led to increase social participation by females and also a transition toward a nuclear family based system. As a result of it, Korea is nowadays confronted with the issue of childcare, which is emerging as a social problem. In Japan, both combined nurturing facilities and the exclusively dedicated facilities for disabled children are institutionally maintained on a consistent basis. In addition, the enactment of the Children Welfare Act has subsequently given birth to the establishment of the 'Minimum Standard Requirements for Children's Welfare Facilities'. With such act and standards in place, much attention is now paid to a physical improvement of disabled children nurturing facilities, too. In order to make the requirements for such facilities more complete and substantial, local governments have enacted their own ordinances on the basis of the major policies regarding the universal designs for the disabled, such as the Heart Building Act. As Japan has a cultural background similar to that of Korea and is equipped with the nurturing facilities systemized in accordance with the symptom and degree of disabilities, it is believed that a study on the current standards for disabled children in Japan will help to provide our domestic standards applicable to such facilities.