• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4A
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• pp.795-808
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• 2006

In this paper, an analytical method which can predict the occurrence of plastic shrinkage cracking on concrete slabs with sequential placement is proposed on the basis of the numerical model introduced in the previous study. The influence of many design variables on plastic shrinkage cracking such as the number of layers and the time interval between layers is quantitatively analyzed through parametric studies using the analytical method. In advance, two equations are introduced to take into account the effect of sequential placement on the plastic shrinkage cracking of concrete slab; The first one is to calculate the time at which the surface of concrete slab begins to dry, and the second one is to determine the critical time interval to prevent the surface drying of previously placed concrete layers. The timing of curing and the sequence of concrete placement, which are important for the prevention of plastic shrinkage cracking, can be effectively planned using the introduced both equations without any rigorous analysis.

• Journal of Electrical Engineering and Technology
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• v.4 no.2
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• pp.175-184
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• 2009

In this paper, a method for optimal measurement placement in the problem of static harmonic state estimation in power systems is proposed. At first, for achieving to a suitable method by considering the precision factor of the estimation, a procedure based on Genetic Algorithm (GA) for optimal placement is suggested. Optimal placement by regarding the precision factor has an evident solution, and the proposed method is successful in achieving the mentioned solution. But, the previous applied method, which is called the Sequential Elimination (SE) algorithm, can not achieve to the evident solution of the mentioned problem. Finally, considering both precision and economic factors together in solving the optimal placement problem, a practical method based on GA is proposed. The simulation results are shown an improvement in the precision of the estimation by using the proposed method.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.12
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• pp.567-572
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• 2005

This paper presents a scheme to design optimal placement of phase-shifting transformers for power system congestion problems. A good design of phase-shifting transformers placement can improve total transfer capability in interconnected systems. In order to find the optimal placement of phase-shifting transformers, the power flows of the interesting transmission lines are evaluated using sequential quadratic programming technique. This algorithm considers power balance equations and security constraints such as voltage magnitudes and transmission line capacities. The proposed scheme is tested in 10 machines 39 buses and IEEE 57 buses systems. Test result shows that the proposed method can find the optimal placement of phase-shifting transformers to solver power system congestion problems.

• Structural Monitoring and Maintenance
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• v.4 no.1
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• pp.53-68
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• 2017

The response sensitivity method in time domain has been applied extensively for damage identification. In this paper, the relationship between the error of damage identification and the sensitivity matrix is investigated through perturbation analysis. An index is defined according to the perturbation amplify effect and an optimal sensor placement method is proposed based on the minimization of that index. A sequential sub-optimal algorithm is presented which results in consistently good location selection. Numerical simulations with a two-dimensional high truss structure are conducted to validate the proposed method. Results reveal that the damage identification using the optimal sensor placement determined by the proposed method can identify multiple damages of the structure more accurately.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1114-1119
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• 1995

This paper presents the development of estimation model and control method based on the new computer vision. This proposed control method is accomplished using a sequential estimation scheme that permits placement of the rigid body in each of the two-dimensional image planes of monitoring cameras. Estimation model with six parameters is developed based on a model that generalizes known 4-axis scara robot kinematics to accommodate unknown relative camera position and orientation, etc. Based on the estimated parameters,depending on each camers the joint angle of robot is estimated by the iteration method. The method is tested experimentally in two ways, the estimation model test and a three-dimensional rigid body placement task. Three results show that control scheme used is precise and robust. This feature can open the door to a range of application of multi-axis robot such as assembly and welding.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.11
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• pp.100-107
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• 1998

This paper presents the development of estimation model and control method based on the new robot vision. This proposed control method is accomplished using the sequential estimation scheme that permits placement of the rigid body in each of the two-dimensional image planes of monitoring cameras. Estimation model with six parameters is developed based on the model that generalizes known 4-axis scara robot kinematics to accommodate unknown relative camera position and orientation, etc. Based on the estimated parameters, depending on each camera the joint angle of robot is estimated by the iteration method. The method is experimentally tested in two ways, the estimation model test and a three-dimensional rigid body placement task. Three results show that control scheme used is precise and robust. This feature can open the door to a range of application of multi-axis robot such as assembly and welding.

• Communications for Statistical Applications and Methods
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• v.9 no.3
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• pp.693-701
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• 2002

When the lowest dose level compared with zero-dose control has significant difference in effect, it is referred as minimum effective dose (MED). In this paper, we discuss several nonparametric methods for finding MED using updated rank at each sequential test step in small sample size and suggest new nonparametric procedures based on placement. Monte Carlo Simulation is adapted to compare power and Familywise Error Rate(FWE) of the new procedures with those of discussed nonparametric tests for finding MED.

• ETRI Journal
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• v.43 no.2
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• pp.260-271
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• 2021

This paper addresses Very large-scale integration (VLSI) placement optimization, which is important because of the rapid development of VLSI design technologies. The goal of this study is to develop a hybrid algorithm for VLSI placement. The proposed algorithm includes a sequential combination of a genetic algorithm and an evolutionary algorithm. It is commonly known that local search algorithms, such as random forest, hill climbing, and variable neighborhoods, can be effectively applied to NP-hard problem-solving. They provide improved solutions, which are obtained after a global search. The scientific novelty of this research is based on the development of systems, principles, and methods for creating a hybrid (combined) placement algorithm. The principal difference in the proposed algorithm is that it obtains a set of alternative solutions in parallel and then selects the best one. Nonstandard genetic operators, based on problem knowledge, are used in the proposed algorithm. An investigational study shows an objective-function improvement of 13%. The time complexity of the hybrid placement algorithm is O(N2).

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.153-160
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• 2003

The objective of optimal placement of dampers for a structure is to maximize the effective-ness of the vibration control with the same number of dampers. While many optimal placement methods of linear viscous dampers have been proposed and used, there are only a few methods for MR dampers. Here some optimal location indices for M dampers are proposed, which are similar to those for linear viscous dampers and show how large the structural responses on each floor are. Every time an additional MR damper is implemented, the optimal location index on each floor is measured, and then the next damper is installed on the floor with the maximum location index. In these sequential procedures, the peak interstory drift, the peak interstory velocity and the absolute acceleration of each floor are selected as the optimal location indeices. Four different earthquakes with various scales are loaded to the 20-story nonlinear benchmark building model (Otori et al. 2000, 2002). Passive On/on algorithms are used in order to represent the control algorithm of M dampers.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.467-472
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• 2003

The objective of optimal placement of dampers for a structure is to maximize the effectiveness of the vibration control with the same number of dampers. While many optimal placement methods of linear viscous dampers have been proposed and used, there are only a few methods for MR dampers. Here some optimal location indices for MR dampers are proposed, which are similar to those for linear viscous dampers and show how large the structural responses on each floor we. Every time an additional MR damper is implemented, the optimal location index on each floor is measured, and then the next damper is installed on the floor with the maximum location index. In these sequential procedures, the peak interstory drift, the peak interstory velocity and the absolute acceleration of each floor are selected as the optimal location indeices. Four different earthquakes with various scales are loaded to the 20-story nonlinear benchmark building model (Otori et at. 2000, 2002). Passive On/Off algorithms are used in order to represent the control algorithm of MR dampers.