• Proceedings of the Korean Information Science Society Conference
• /
• 2007.06b
• /
• pp.519-524
• /
• 2007

본 논문에서는 기존의 CDP(Congestion Driven Placement) 기법[5]을 개선하여 좀 더 빠른 시간에 배선 밀집도를 효과적으로 해결할 수 있는 기법, 즉 ECDP(Effective Congestion Driven Placement) 기법을 제안한다. ECDP는 force-directed 기법을 이용한 배선밀집도 해결 기법으로써 기존의 국부적인 셀 이동방식을 개선한다. 제시된 기법은 배치 영역의 빈(bin) 상에 셀 밀집도를 해결하는 방향으로 분산력을 구한 후 밀집된 셀을 분산시킴으로써 배선밀집도를 개선시킨다. 실험을 통한 결과에서 CDP와 비교 해 볼 때 배선밀집도와 수행속도 모두 제안기법이 우수한 결과를 보인다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2005.11a
• /
• pp.853-856
• /
• 2005

VLSI 설계에서 셀 배치단계는 칩의 성능에 영향을 미치는 중요한 단계로서, 셀 배치문제의 주요한 목적비용으로는 배선길이, 타이밍(timing) 그리고 배선밀집도 (routing congestion)가 있다. 기존 연구에서 배선길이를 줄이기 위한 많은 기법들이 소개되었으나 배선 밀집도를 추정하고 이를 어떻게 줄일 것인가에 대한 연구는 상대적으로 많이 되어있지 않다. 본 논문에서는 셀 배치후에, 주어진 배치를 바탕으로 배선밀집도를 예측하고 배선밀집도가 높은 지역을 국부적으로 해결하는 새로운 기법을 제안한다.

• The KIPS Transactions:PartA
• /
• v.13A no.1 s.98
• /
• pp.57-70
• /
• 2006

This paper describes a new effective algorithm to estimate routing congestion and to resolve highly congested regions for a given detailed placement. The major features of the proposed technique can be summarized as follows. Firstly, if there are congested regions due to some nets which pass through the regions it can determine which cells affect those congested spots seriously and moves some of them to resolve congestion effectively. Secondly, since the proposed technique uses the ripple movement technique to move cells it resolves congestion without sacrificing wire length. Thirdly, we use an efficient incremental data structure to trace the changes in congestion and wire length as cells move. Hence, selection of cells to move could be very accurate and fast in the course of iteration. Finally, although an MST net model is used to resolve congestion in this paper, proposed technique can be work with any net model. Particularly, if proposed technique can obtain routing information from a real router, congestion can be resolved more effectively. Experimental results show that the proposed technique can resolve congestion effectively and efficiently without sacrificing wire length.

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

• Proceedings of the Korean Information Science Society Conference
• /
• 2002.04a
• /
• pp.664-666
• /
• 2002

현대의 Deep-Sumicron Technology(DSM)에서 배선은 논리 구성 요소들보다 더욱 중요한 위치를 차지 하게 되었다. 최근에, [2]는 연산 회로를 합성하기 위해 비트 단위의 최적 지연시간의 partial product reduction tree(PPRT)를 생성하는 방법을 제시하였고, 이는 현재의 최적 지연시간을 갖는 회로를 능가한다. 그러나, [2]를 포함하는 기존의 합성방법에서는, 합성의 복잡함이나, 배선에서 발생하는 여러가지 예상치 못하는 문제등으로 인하여 최종 배선을 고려하지 못하는 회로를 생성하며, 이는 길고 복잡하며, 특정한 부분에 밀집 되어 있는 배선을 형성하는 결과를 낳게 된다. 이러한 제한점을 극복하기 위하여, 우리는 carry-save-adder(CSA)를 이용한 새로운 모듈 함성 알고리즘을 제시한다. 이는 단지 상위 단계에서의 회로의 지연시간만을 고려한 알고리즘이 아니라, 이후의 배선을 고려하여 최종 배선에서 규칙적인 배선 토폴로지를 생성한다.

• Journal of KIISE:Computer Systems and Theory
• /
• v.33 no.1_2
• /
• pp.92-104
• /
• 2006

The proposed method for a force directed global placement algorithm exploits and extends techniques from two leading placers, Kraftwerk (& KraftwerkNC) and Mongrel. It combines the strengths of KraftwerkNC, force directed global placer, and Mongrel's ripple move technique which resolves cell overlaps effectively The proposed technique uses the force spreading technique used in Kraftwerk to optimize the ripple movement. While it is resolving the cell overlap and optimizing wire length physical net constraints are considered for timing. The experimental results obtained by the proposed approach shows significant improvement on wire length as well as on timing.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.2
• /
• pp.147-154
• /
• 1989

An effective placement of macro blocks having arbitrary width and height is very important in reducing the chip area and the signal delay. In this paper, we proposed a method of macro block placement to obtain the globally optimal placement using simulated annealing, and an efficient algorithm for eliminating the overlaps between the rectangular macro blocks which may remain even after the simulated annealing process is terminated. Each macro block was enlarged to take into account minimal routing area, and these macro blocks were compacted as much as possible during the placement. This procedure was implemented in C language running on MV10000/UNIX computer system, and good placements were obtained by applying this procedure to two circuits which were consisted of 50 and 160 macro blocks respectively. Several parameters giving great effects to final placements were investigated.

• Journal of the Korean association of regional geographers
• /
• v.18 no.4
• /
• pp.464-472
• /
• 2012

To assess the space-time clustering of FMD(Foot-and-Mouth Disease) epidemic occurred in Korea between November 2010 to April 2011, geographical information system (GIS)-based spatial analysis technique was used. Farm address and geographic data obtained from a commercial portal site were integrated into GIS software, which we used to map out the color-shading geographic features of the outbreaks through a process called thematic mapping, and to produce a visual representation of the relationship between epidemic course and time throughout the country. FMD cases reported in northern area of Gyounggi province were clustered in space and time within small geographic areas due to the environmental characteristics which livestock population density is high enough to ease transmit FMD virus to the neighboring farm, whereas FMD cases were clustered in space but not in time for southern and eastern area of Gyounggi province. When analyzing the data for 7-day interval, the mean radius of the spatial-time clustering was 25km with minimum 5.4km and maximum 74km. In addition, the radius of clustering was relatively small in the early stage of FMD epidemic, but the size was geographically expanded over the epidemic course. Prior to implementing control measures during the outbreak period, assessment of geographic units potentially affected and identification of risky areas which are subsequently be targeted for specific intervention measures is recommended.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.23 no.4
• /
• pp.140-155
• /
• 2020

This study was conducted to identify the location characteristics of infected farms in the areas where livestock diseases were clustered(southern Gyeonggi-do and Chungcheong-do), analyze the probability of disease occurrence in poultry farms, find out the areas corresponding to the conditions, and use them as the basis for prevention of livestock diseases, selection of discriminatory prevention zones, and establishment of prevention strategies and as the basic data for complementary measures. The increase of one poultry farm within a radius of 3-kilometers increases the risk of HPAI infection by 10.9% compared to the previous situation. The increase of 1m in distance from major roads with two lanes or more reduces the probability of HPAI infection by 0.001% compared to the previous situation. If the distance of the poultry farm located with 15 kilometers from a major migratory bird habitat increases by 15 to 30 kilometers, the chance of infection with HPAI is reduced by 46.0%. And if the distance of the same poultry farm increase by more than 30 kilometers, the chances of HPAI infection are reduced by 88.5%. Based on the results of logistic regression, the predicted probability was generated and the actual area of the location condition with 'more than 15 poultry farms within 3km a radius of, within 1km distance from major roads, and within 30km distance from major migratory birds habitat was determined and the infection rate was measured. It is expected that the results of this study will be used as basic data for preparing the data and supplementary measures when the quarantine authorities establish discriminatory quarantine areas and prevention strategies, such as preventive measures for the target areas and farms, or control of vehicles, by identifying the areas where livestock diseases are likely to occur in the region.