• Journal of KIISE:Computing Practices and Letters
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• v.14 no.4
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• pp.431-435
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• 2008

Since previous work CDP(Congestion Driven Placement) [1] considers all possible directions to move every cell in nets which contribute highly to routing congestion, it consumes CPU time a lot. In this paper, we propose a faster global placement technique, so called ICDGP(Improved Congestion Driven Global Placement) to relieve the routing congestion. ICDGP uses the force-directed method to determine the target locations of the cells in the nets in the congested spots, and considers only to move the target location for each cell. If moving multiple cells simultaneously is considered better than moving each cell one by one it moves multiple cells simultaneously. By experimental results, ICDGP produces less congested placement than CDP does. Particularly, the CPU time is reduced by 36% on average.

• Journal of Practical Engineering Education
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• v.8 no.2
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• pp.129-136
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• 2016

In addition to the quantitative growth of domestic field placement, there is a growing interest in global field placement and participation of government and universities is increasing. The global field experience of university students provides students with advanced skills and experience of overseas companies as well as opportunities to acquire foreign language ability and global culture suitable for industrial needs that require global competence. Students can cultivate global mind and major practical skills so that it has the advantage of linking to overseas employment. In order to be successful global field placement, the university has to promote to participate in the company including the curriculum related to the student's major and provide comprehensive support including student safety, but the resources of the university are only limited. In this paper, we propose a method to activate global field placement in cooperation with local partner universities based on Kumoh Institute of Technology case study.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.6 s.348
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• pp.23-29
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• 2006

In this paper, we propose an effective global placement technique using quadratic programming(QP). In order to resolve cell congestion problem which is a drawback of QP based placement techniques, additional force and grid pre-warping technique are used. We devised a new density function for evaluating proper additional force which depends on density. Grid pre-warping technique relocates cells over entire area according to the relative ordering between coordinates of cells. Using the additional force obtained by the new density function and applying the pre-warping technique iteratively we obtained a well-distributed global placement. Mongrel which is a middle-down methodology based placer takes such a good global placement as an initial placement and produces a final detailed placement. Experimental results show that proposed technique outperforms the FM algorithm based global placement and are comparable with the well-known leading placers, FengShui, Dragon.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.5
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• pp.748-754
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• 2008

The general capacitor placement problem is a combinatorial optimization problem having an objective function composed of power losses and capacitor installation costs subject to bus voltage constraints. In this paper, a global optimization technique, which employing the chaos search algorithm, is applied to solve optimal capacitor placement problem with reducing computational effort and enhancing global optimality of the solution. Chaos method in optimization problem searches the global optimal solution on the regularity of chaotic motions and easily escapes from local or near optimal solution than stochastic optimization algorithms. The chaos optimization method is tested on 9 buses and 69 buses system to illustrate the effectiveness of the proposed method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.10
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• pp.1598-1605
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• 1989

This paper describes an efficient global cell (module) placement strategy called HALO (Hierarchical Alternating Linear Ordering)which generates global 2-D placement of circuit modules by hierarchical application of linear ordering in alternating direction. We tried, in principle, to explain why HALO should perform better than other typical, somehat successful, analytical approaches such as min-cut, force-directed relaxation(FDR)or its likes. We have implemented HALO as a program for standard cell placement. Experimental results on two benchmark circuits, primary and primary 2 consisting of 752 and 2907 cells, respectively have shown a decrease of half-perimeter routing length by 7% and 24%, respectively compared to the best available results obtained so far. Total CPU time including the following detailed placement was less than half of the earlier work.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.6
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• pp.58-65
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• 1993

In this research, we developed a new algorithm for hierarchical placement of integrated circuits. For efficient placement of a large circuit, the given circuit is recursively partitioned to form a hierarchy tree and then simulated-annealing-based placement method is applied at each level of the hierarchy to find a near optimum solution. During the placemtnt, global optimization is performed at high levels of the hierarchy and local optimization is performed at low levels. When compared with conventional placement methods, the new hierarchical placement method produced favorable results.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.10
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• pp.595-602
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• 2003

This Paper presents an efficient hybrid techniques for a standard cell placement. The prototype tool adopts a middle-down methodology in which an n${\times}$m grid is imposed over the layout area and cells are assigned to bins forming a global placement. The optimization technique applied in this phase is based on the Relaxation-Based Local Search (RBLS) framework [12］in which a combinatorial search mechanism is driven by an analytical engine. This enables a more global view of the problem and results in complex modifications of the placement in a single search“move.”Details of this approach including a novel placement legalization procedure are presented. When a global placement converges, a detailed placement is formed and further optimized by the optimal interleaving technique[13］. Experimental results on MCNC benchmarking circuits are presented and compared with the Feng Shui's results in［14］. Solution Qualifies are almost the same as the Feng Shui's results.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.12
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• pp.61-70
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• 2005

In this paper, we propose an efficient global placement algorithm which is an enhanced version of Hybrid Placer$^{[25]}$, a standard cell placement tool, which uses a middle-down approach. Combining techniques used in the well-known partitioner hMETIS and the RBLS(Relaxation Based Local Search) in Hybrid Placer improves the quality of global placements. Partitioning techniques of hMETIS is applied in a top-down manner and RBLS is used in each level of the top-down hierarchy to improve the global placement. The proposed new approach resolves the problem that Hybrid Placer seriously depends on initial placements and it speeds up without deteriorating the placement quality. Experimental results prove that solutions generated by the proposed method on the MCNC benchmarks are comparable to those by FengShui which is a well known placement tool. Compared to the results of the original Hybrid Placer, new method is 5 times faster on average and shows improvement on bigger circuits.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06a
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• pp.391-394
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• 2011

3rd party content service is a consumer-based wide selection of contents in which IPTV provider believes will enhance the service considerably extending the variety of contents to finally provide a personalized service. Therefore, the combination of 3rd party content services and the IPTV infrastructure creates a good revenue opportunity but they need to be created. IPTV offers to create personalized channels to distribute 3rd party content service. However, the cost of $3^{rd}$ party content delivery is high when the service is provided from a faraway server. IPTV provider requires an effective strategy of replica placement to minimize the cost without a tradeoff on the performance. We propose a cluster-based strategy of replica placement to find the right balance between cost and performance. The results demonstrate the achievement of an outstanding delivery time and low cost.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.2
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• pp.130-139
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• 1995

A hierarchical placement system based on routing region assignment has been developed to increase the probability of routing completion after placement. While most of the existing placement systems attempt to reduce the cell density at the portions where routing density is high, our method is distinguished in that specific routing regions are allocated to secure complete routing where the routing density is greater than the routing capacity. Hierarchy is vuilt by clustering and recursive paritioning, and the initial placement obtained by partitioning at each level is improved by using the region refinement algorithm. After placement at each hierarchical level, global routing is performed and fouting regions are assigned, if routing density is greater than routing capacity, to be considered at the next level of placement. the proposed algorithm has been implemented and applied to place several industrical gate-array circuits. A couple of circuits which cannot be routed by using conventional placement techniques can be completely routed by using our new placement technique with routing region assignment.