• Structural Engineering and Mechanics
• /
• v.74 no.4
• /
• pp.521-532
• /
• 2020

A floating dry dock is an advanced structure that can provide a solution for dry dock space shortages. The critical point in floating dock operation is compensating the deflection caused by a heavy payload by adjusting the water level in the ballast system. An appropriate ballasting plan warrants safe and precise construction on a floating dock. Particularly, in the case of a 2D floating dock, ballasting plan evaluation is crucial due to complex deformation modes. In this paper, we developed a method to calculate the optimal ballasting plan for accurate and precise construction on a 2D floating dock. The finite element method was used for considering the flexibility of the floating dock as well as the construction blocks. Through a gradient-based optimization algorithm, the optimal ballasting plan for the given load condition was calculated in semi-real time (5 min). The present method was successfully used for the actual construction of an offshore structure on the 2D floating dock.

• Proceedings of the KWS Conference
• /
• 2004.05a
• /
• pp.18-20
• /
• 2004

This study is to find the optimal work plan of robot welding in the subassembly process of shipbuilding and to verify the found solution through 3-D simulation. The optimal work plan was established by evenly distributing the work amount to each stage and finding the shortest work sequence. The shortest work sequence was found by using the genetic algorithm. The result was compared with the practically adopted case and verified through the 3-D simulation.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.14 no.24
• /
• pp.1-5
• /
• 1991

Various linear cost models have been proposed that can be used to determine a sampling plan by attributes. This paper is concerned with this sampling cost model when the probability that the number of nonconforming item is smaller than the break-even quality level is known. In addition to this situation, a constraint by AOQL is considered. Under these conditions, optimal sampling plan which minimize the average cost per lot is suggested.

• Journal of the Korean Data and Information Science Society
• /
• v.26 no.1
• /
• pp.271-280
• /
• 2015

In this paper, the maximum likelihood estimators for parameters are derived under three step-stress accelerated life tests for Type-I hybrid censored data. The exponential distribution and the cumulative exposure model are considered based on the assumption that a log quadratic relationship exits between stress and the mean lifetime ${\theta}$. The test plan to search optimal stress change times minimizing the asymptotic variance of maximum likelihood estimators are presented. A numerical example to illustrate the proposed inferential procedures and some simulation results to investigate the sensitivity of the optimal stress change times by the guessed parameters are given.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1999.10c
• /
• pp.783-788
• /
• 1999

In this study, a decision support system (DSS) was developed to calculate optimal wastetreatment cost, treatment level and treatment quantity of various pollutants for applying for in rural basin. The DSS includes a gegraphic informatino system (GIS), relational database system (RDBS), water quality models(Loading function , WASP5), watershed pollution load calculation module(SPLC), optimal water quality management plan to satisfy the water quality regulations. The system can be modified by user to trace the optimal condition for decision. The effort was conducted to apply the developed DSS to select the for optimal water quality management plan small rural basin called Kwanri Stream.

• Journal of Electrical Engineering and Technology
• /
• v.5 no.2
• /
• pp.239-245
• /
• 2010

Today, as power trades between generators and loads are liberalized, the uncertainty level of power systems is rapidly increasing. Therefore, transmission operators are required to incorporate these uncertainties when establishing an investment plan for effective operation of transmission facilities. This paper proposes the methodology for an optimal solution of transmission expansion plans for the long-term in a deregulated power system. The proposed model uses the probabilistic cost of transmission congestion for various scenarios and the annual increasing rates of loads. The locations and the installation times of expanded transmissions lines with minimum cost are acquired by the model. To minimize the investment risk, the Mean-Variance Markowitz portfolio theory is applied to the model. In a case study, the optimal solution of a transmission expansion plan is obtained considering the uncertain power market.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.4
• /
• pp.560-566
• /
• 2008

Today, as the power trades between generation companies and power customer are liberalized, the uncertainty level of operated power system is rapidly increased. Therefore, transmission operators as decision makers for transmission expansion are required to establish a deliberate investment plan for effective operations of transmission facilities considering forecasted conditions of power system. This paper proposes the methodology for the optimal solution of transmission expansion in deregulated power system. The paper obtains the expected value of transmission congestion cost for various scenarios by using occurrence probability. In addition, the paper assumes that increasing rates of loads are the probability distribution and indicates the location of expanded transmission line, the time for transmission expansion with the minimum cost for the future by performing the Montecarlo simulation. To minimize the investment risk as the variance of the congestion cost, Mean-Variance Markowitz portfolio theory is applied to the optimization model by the penalty factor of the variance. By the case study, the optimal solution for transmission expansion plan considering the feature of market participants is obtained.

• 제어로봇시스템학회:학술대회논문집
• /
• 1992.10b
• /
• pp.79-84
• /
• 1992

Path planning is an important task for optimal motion of a robot in structured or unstructured environment. The goal of this paper is to plan the optimal collision-free path in 3D, when a robot is navigated to pick up some tools or to repair some parts from various locations. To accomplish the goal, the Path Coordinator is proposed to have the capabilities of an obstacle avoidance strategy and a traveling salesman problem strategy (TSP). The obstacle avoidance strategy is to plan the shortest collision-free path between each pair of n locations in 2D or in 3D. The TSP strategy is to compute a minimal system cost of a tour that is defined as a closed path navigating each location exactly once. The TSP strategy can be implemented by the Hopfield Network. The obstacle avoidance strategy in 2D can be implemented by the VGraph Algorithm. However, the VGraph Algorithm is not useful in 3D, because it can't compute the global optimality in 3D. Thus, the Path Coordinator is used to solve this problem, having the capabilities of selecting the optimal edges by the modified Genetic Algorithm and computing the optimal nodes along the optimal edges by the Recursive Compensation Algorithm.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.31 no.5
• /
• pp.401-410
• /
• 2013

Due to the increasing need for spatial information, there have been a lot of research related with monitoring and revision of changed regions for the acquisition of the accurate and latest information. In this paper, the optimal monitoring management plan for changed regions with respect to the revision periods was proposed. For this purpose, the representative monitoring methods, which are based on database, professional manpower and crowdsourcing of continuous revision, and aerial imagery, satellite imagery and LiDAR of cyclic revision, were investigated. Then, the properties and application status of monitoring systems in Korea were illustrated according to the methods. Finally, the optimal monitoring management plan for continuous and cyclic revisions was suggested through the comparison of properties and revisionable objects of each method. From the result, it was shown to be appropriate for the optimal monitoring management plan of continuous revision as using Internet-Architectural Information System (e-AIS) database cooperated with professional manpower and crowdsourcing, and cyclic revision as using domestic high-resolution satellite images and LiDAR data processed semi-automatically.

• Journal of Applied Reliability
• /
• v.7 no.2
• /
• pp.57-72
• /
• 2007

This paper suggests an approach for using ALTA 7 PRO to design accelerated life test plans. Conducting a accelerated life test requires finding life distributions at different stress levels and determining an appropriate life-stress relationship. Moreover, a test plan needs to be developed. In its optimal test plan, stress levels are determined and the proportions of test units are assigned at each stress level so that asymptotic variance of the maximum likelihood estimate of a (log) percentile of the life distribution at the design stress is minimized. Examples are presented for usage.