• Journal of Korea Society of Digital Industry and Information Management
• /
• v.17 no.2
• /
• pp.13-20
• /
• 2021

Placement is a very important step in the VLSI physical design process. It is the problem of placing circuit modules to optimize the circuit performance and reliability of the circuit. It is used at the layout level to find strongly connected components that can be placed together in order to minimize the layout area and propagation delay. The most popular algorithms for circuit placement include the cluster growth, simulated annealing, integer linear programming and genetic algorithm. In this paper we propose a adapted genetic algorithm searching solution space for the placement problem, and then compare it with simulated annealing and genetic algorithm by analyzing the results of each implementation. As a result, it was found that the adaptive genetic algorithm approaches the optimal solution more effectively than the simulated annealing and genetic algorithm.

• Journal of Platform Technology
• /
• v.10 no.4
• /
• pp.70-81
• /
• 2022

In this paper, we proposed a Virtual Machine Placement (VMP) method to provide live vertical scaling services for cloud resources. Since free space on the physical server must be secured in advance for vertical scaling, a "general-mixed-vertical" mode conversion algorithm based on the FirstFit placement strategy that variably adjusts the allocation ratio of virtual servers to physical servers for this purpose is presented. Simulations were performed using parameters such as vertical scaling ratio, virtualization ratio, and free resource ratio. When the vertical scaling ratio is 50%, considering free space, 150% of resources are required as a whole, but simulation results of the proposed algorithm show that only up to 125% of free space is required.

• Korean Journal of Radiology
• /
• v.2 no.4
• /
• pp.204-209
• /
• 2001

Objective: To determine the feasibility of transcaval transjugular intrahepatic portosystemic shunt (TIPS) in patients with occluded previous TIPS. Materials and Methods: Between February 1996 and December 2000 we performed five transcaval TIPS procedures in four patients with recurrent gastric cardiac variceal bleeding. All four had occluded TIPS, which was between the hepatic and portal vein. The interval between initial TIPS placement and revisional procedures with transcaval TIPS varied between three and 31 months; one patient underwent transcaval TIPS twice, with a 31-month interval. After revision of the occluded shunt failed, direct cavoportal puncture at the retrohepatic segment of the IVC was attempted. Results: Transcaval TIPS placement was technically successful in all cases. In three, tractography revealed slight leakage of contrast materials into hepatic subcapsular or subdiaphragmatic pericaval space. There was no evidence of propagation of extravasated contrast materials through the retroperitoneal space or spillage into the peritoneal space. After the tract was dilated by a bare stent, no patient experienced trans-stent bleeding and no serious procedure-related complications occurred. After successful shunt creation, variceal bleeding ceased in all patients. Conclusion: Transcaval TIPS placement is an effective and safe alternative treatment in patients with occluded previous TIPS and no hepatic veins suitable for new TIPS.

• Journal of Power Electronics
• /
• v.12 no.2
• /
• pp.368-376
• /
• 2012

This paper deals with an optimization approach of 3D space placement of power components under volume and thermal constraints. It consists in optimizing semiconductors positions on a heat sink by respecting the components junction temperatures and minimizing the heat sink size. The aim is to remove risks on the 3D converter components placement and ensure their effective integration before carrying out the first physical prototype. This approach is based on coupling an optimization environment with a thermal finite element simulation tool. A pre-sizing step using analytical models is performed to set the optimization computations coupled to numerical simulation.

• Proceedings of the KIEE Conference
• /
• 1988.07a
• /
• pp.529-532
• /
• 1988

This paper proposes a graph matching algorithm based on simulated annealing, which assures the globally optimal solution for circuit partitioning for the placement in the rectilinear region occurring as a result of the pre-placement of some macro cells, or onto the nonplanar surface in some military or space applications. The circuit graph ($G_{C}$) denoting the circuit topology is formed by a hierarchical bottom-up clustering of cells, while another graph called region graph ($G_{R}$) represents the geometry of a planar rectilinear region or a nonplanar surface for circuit placement. Finding the optimal many-to-one vertex mapping function from $G_{C}$ to $G_{R}$, such that the total mismatch cost between two graphs is minimal, is a combinatorial optimization problem which was solved in this work for various examples using simulated annealing.

• 한국HCI학회:학술대회논문집
• /
• 2009.02a
• /
• pp.428-431
• /
• 2009

Recently, uses of a large, wide screen monitors are general, so people that efficiently use work area of monitor is encreasing. Use pattern of monitor is being changed just using one window to many windows at a time. In this paper, I will explain develop windows placement system for efficient use monitor. It is different from other general utility about windows placement system because users can easily change windows placement to use preview window. The future, a large, wide screen monitors to keep pace with the demand to take advantage of the window to satisfy the needs of the user to manually adjust the window to the inconvenience that will be resolved.

• Structural Monitoring and Maintenance
• /
• v.9 no.1
• /
• pp.59-80
• /
• 2022

In the present study, the objective is to detect the structural damages using the responses obtained from the sensors at the optimal location under uncertainty conditions. Reducing the error rate in damage detection process due to responses' noise is an important goal in this study. In the proposed algorithm for optimal sensor placement, the noise of responses recorded from the sensors is initially reduced using the principal component analysis. Afterward, the optimal sensor placement is obtained by the damage detection equation based sensitivity analysis. The sensors are placed on degrees of freedom corresponding to the minimum error rate in structural damage detection through this procedure. The efficiency of the proposed method is studied on a truss bridge, a space dome, a double-layer grid as well as a three-story experimental frame structure and the results are compared. Moreover, the performance of the suggested method is compared with three other algorithms of Average Driving Point Residue (ADPR), Effective Independence (EI) method, and a mass weighting version of EI. In the examples, young's modulus, density, and cross-sectional areas of the elements are considered as uncertainty parameters. Ultimately, the results have demonstrated that the presented algorithm under uncertainty conditions represents a high accuracy to obtain the optimal sensor placement in the structures.

• The Korean Journal of Pain
• /
• v.25 no.3
• /
• pp.183-187
• /
• 2012

The use of fluoroscopy guidance together with the loss of resistance technique during epidural injections has been advocated lately; moreover, epidural injections in the absence of fluoroscopic guidance have a high rate of inaccurate needle-tip placement during the injections. However, the approach to the lower cervical and upper thoracic epidural space may be challenging due to its obscure lateral fluoroscopic views from overlying normal tissue structures. In this case, we report an alternative oblique C-arm fluoroscopy guided view approach to supplement the standard anterior-posterior and lateral fluoroscopic views to facilitate successful needle placement and precise anatomical localization of the epidural space.

• Journal of KIISE:Computer Systems and Theory
• /
• v.33 no.8
• /
• pp.514-523
• /
• 2006

In this paper we propose an extended interleaving technique to improve a detailed placement. The existing row-based interleaving technique allows cells to move only within a row and it can be applied when there is no space between cells. The proposed extended-interleaving technique releases such constraints so that cells can move along with a vertical line parallel to a y-axis and space between cells is properly handled. Converged detailed-placements by a mature CAD tool have been improved by the proposed interleaving technique by 9.5% on average in half-perimeter wire length.

• Smart Structures and Systems
• /
• v.26 no.6
• /
• pp.721-733
• /
• 2020

The present study investigates the employing of piezoelectric patches in active control of a sandwich plate. Indeed, the active control and optimal patch distribution on this structure are presented together. A sandwich plate with honeycomb core and composite reinforced by carbon nanotubes in facesheet layers is considered so that the optimum position of actuator/sensor patches pair is guaranteed to suppress the vibration of sandwich structures. The sandwich panel consists of a search space which is a square of 200 × 200 mm with a numerous number of candidates for the optimum position. Also, different dimension of square and rectangular plates to obtain the optimal placement of piezoelectric actuator/senor patches pair is considered. Based on genetic algorithm and LQR, the optimum position of patches and fitness function is determined, respectively. The present study reveals that the efficiency and performance of LQR control is affected by the optimal placement of the actuator/sensor patches pair to a large extent. It is also shown that an intelligent selection of the parent, repeated genes filtering, and 80% crossover and 20% mutation would increase the convergence of the algorithm. It is noted that a fitness function is achieved by collection actuator/sensor patches pair cost functions in the same position (controllability). It is worth mentioning that the study of the optimal location of actuator/sensor patches pair is carried out for different boundary conditions of a sandwich plate such as simply supported and clamped boundary conditions.