• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.11
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• pp.128-139
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• 1996

In this paper, we propose an algorithm to solve the problem of placement of rectangular blocks whose sizes and shpaes are pre-determined. The proposed method solves the placement of many retangular blocks of different sizes and shapes in a hierarchical manner, so as to minimize the chip area. The placement problem is divided into several sub-problems: hierarchical partioning, hierarchical area/shape estimation, hierarchical pattern pacement, overlap removal, and module rotation. After the circuit is recursively partitioned to build a hierarchy tree, the necessary wiring area and module shpaes are estimated using the resutls of the partitioning and the pin information before the placement is performed. The placement templaes are defined to represent the relative positions of the modules. The area and the connectivity are optimized separately at each level of hierachy using the placement templates, so the minimization of chip area and wire length can be achieved in a short execution time. Experiments are made on the MCNC building block benchmark circuits and the results are compared with those of other published methods. The proposed technique is shown to produce good figures in tems of execution time and chip area.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.925-928
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• 2013

In this paper, we propose a relay-based wireless power transmission scheme in order to solve the problems of an existing wired power transmission for energy harvesting system. The proposed scheme can be transferred electromagnetic induction-based wireless power transmission by placing a 4-way coils in the energy block. We confirm the reliability of the electricity transmission through the relay control algorithm. Consequently, the proposed scheme can extend the transmit receive paths of transmission power.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.69-71
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• 2012

전투체계는 일반적으로 대규모 시스템으로 다양한 부체계들로 구성되며, 각각은 서로 다른 업체에서 독립적으로 개발되어 서로 다른 컴퓨팅 플랫폼에서 동작한다. 이러한 다양한 플랫폼에서 동작하는 부체계들을 관리하는 것이 쉽지 않다. 그래서 현재 전투체계를 통합 관리하기 위한 방안으로 정보모델을 이용하는 방안이 제시되고 있다. 일반적으로 정보모델은 플랫폼에 독립적인 형태로 구성하기 위해 XML을 이용한다. 그러나 전투체계와 같이 복잡한 시스템에 대한 정보모델을 사용자가 직접 관리하기란 쉽지 않다. 이는 관리 대상 체계들의 정보뿐만 아니라 하위 시스템 및 애플리케이션들 간의 관계를 모델링하는 것이 필요하기 때문이다. 이 논문에서는 객체지향 개념을 바탕으로 전투체계를 관리하기 위한 정보모델을 제시하고, 정보모델을 효과적으로 구축하기 위해 블록 기반으로 시스템들의 정보와 시스템들 간의 배치 관계 등을 표현할 수 있는 정보모델 모델러를 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.33-35
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• 1999

이 논문에서는 폭넓게 사용되지만 컴퓨터의 메모리 계층 구조상에서 병목지점으로 알려진 하드디스크의 획기적인 성능향상을 위해서 메모리 시스템이 내장된 새로운 형태의 디스크 구조를 제안한다. 제안하는 디스크 구조에서는 디스크에 메모리를 혼용하여 사용함으로써 디스크 응답시간을 크게 줄이고, 입출력을 빠르게 처리할 수 있다. 64MB까지의 디스크 메모리를 탑재한 경우 두 가지 실제 트레이스에 의한 시뮬레이션 결과 20여명이 사용하는 공유 시스템의 작업부하에서는 최대 80% 정도의 히트율을 통하여 최대 1/2, 그리고 개인용 시스템의 경우 초대 85% 가량의 히트율을 통해 1/5 수준으로 응답시간을 단축할 수 있었다. 앞으로 디스크에 단순히 메모리를 추가하는데 그치지않고 데이터 블록의 배치 방법, 데이터 분산 배분 방법, 보관정책, 선인출 방법 등을 이용하면 추가된 디스크 메모리의 효용을 극대화할 수 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.181-183
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• 2003

본 논문에서는 적응적인 스트리밍 시스템 환경에서 계층적으로 압축된 멀티미디어 데이터의 저장구조와 자료인출 원리를 분석한다. 또한 네트워크 시뮬레이션을 이용, 네트워크 상에서 다양한 멀티미디어 스트리밍 부하의 특성을 분석한다. 두 가지 분석을 통해 기존의 멀티미디어 저장방식이 다양한 네트워크 환경과 시간에 따라 전송율이 변화하는 적응적 스트리밍 시스템의 요구를 충족시키지 못한다는 것을 확인한다. 이를 개선하기 위해 제안된 하모닉 인터리빙은 하모닉 인터리빙 방식은 전송비율이 높은 멀티미디어 데이터 블록의 위치를 연속적으로 배치하기 위해서 전송비율이 높은 계층과 그렇지 않은 계층을 별도의 그룹으로 나누어서 저장하는 방식이다. 실험을 통해서 네트워크 상황이 전송하고자 하는 영화의 대역폭을 보장하지 못하는 환경에서는 기존의 저장방식보다 새로 제안된 저장방식이 디스크 사용율에 있어 우수한 성능을 나타냄을 보인다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.273-279
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• 2007

I evaluate the BER performance of OFDM systems in frequency selective Doppler time variant fading channels, considering the pilot patterns for channel estimation. The performance of the systems is degraded due to channel estimation error. For the reduction of performance degradation in acceptable level, the optimum distance of pilot symbols in pilot pattern is 5 subcarriers in frequency domain and 6 OFDM block in time domain.

• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.199-210
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• 2022

This study was conducted to investigate the effects of the type and number of enrichments on growth performance, blood characteristics, footpad dermatitis (FPD) incidence, and litter moisture in broilers. A total of 1,140 1-day-old male Ross 308 broilers were assigned to a 3 × 2 factorial arrangement based on the type of enrichment (cabbage, alfalfa block, and angle sawdust) and the number of enrichments (one or two per 38 broilers). The growth performance, blood characteristics, FPD incidence, and litter moisture of the broilers were evaluated. Body weight and feed conversion rate were significantly improved (P<0.05) in the alfalfa block and sawdust group compared to the cabbage group, but there was no interaction effect between the type and number of enrichments. The heterophil/lymphocyte ratio, a stress index, was significantly decreased (P<0.05) in the alfalfa block and sawdust groups compared with the cabbage group. The incidence of FPD was significantly decreased in the order of cabbage (3.78), alfalfa block (3.06), and sawdust (1.43) groups at 5 weeks of age. Moreover, there was a significant decrease in the incidence of FPD (P<0.05) in the one-enrichment group compared with the two-enrichment group. Litter moisture at 5 weeks of age was significantly reduced in the sawdust group compared to the cabbage and alfalfa groups, but there was no significant difference in the interaction between the type and number of enrichments. It was concluded that sawdust enrichment positively influenced both growth performance and the animal welfare of broilers. In addition, it is expected that sawdust can be used to regulate litter moisture.

• The Transactions of the Korea Information Processing Society
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• v.6 no.9
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• pp.2294-2304
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• 1999

Our research purpose in this paper is to improve the performance of query processing in GIS(Geographic Information System) by enhancing the I/O performance exploiting parallel I/O and efficient disk access. By packing adjacent spatial data, which are very likely to be referenced concurrently, into one block or continuous disk blocks, the number of disk accesses and the disk access overhead for query processing can be decreased, and this eventually leads to the I/O time decrease. So, in this paper, we proposes EPR(Enhanced Parallel R-tree) indexing method which integrates the parallel I/O method of the previous Parallel R-tree method and a packing-based clustering method. The major characteristics of EPR method are as follows. First, EPR method arranges spatial data in the increasing order of proximity by using Hilbert space filling curve, and builds a packed R-tree by bottom-up manner. Second, with packing-based clustering in which arranged spatial data are clustered into continuous disk blocks, EPR method generates spatial data clusters. Third, EPR method distributes EPR index nodes and spatial data clusters on multiple disks through round-robin striping. Experimental results show that EPR method achieves up to 30% or more gains over PR method in query processing speed. In particular, the larger the size of disk blocks is and the smaller the size of spatial data objects is, the better the performance of query processing by EPR method is.

• Journal of the Korean Society of Radiology
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• v.18 no.2
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• pp.65-71
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• 2024

To achieve high resolution and sensitivity of positron emission tomography (PET) for small animals, the detector is constructed using very thin and long scintillation pixels. Due to the structure of these scintillation pixels, spatial resolution deterioration occurs outside the system's field of view. To solve this problem, we designed a detector that could improve spatial resolution by measuring the interaction depth and improve sensitivity by using a quasi-block scintillator. A quasi-block scintillator size of 12.6 mm x 12.6 mm x 3 mm was arranged in four layers, and optical sensors were placed on all sides to collect light generated by the interaction between gamma rays and the scintillator. DETECT2000 simulation was performed to evaluate the performance of the designed detector. Flood images were acquired by generating gamma-ray events at 1 mm intervals from 1.3 mm to 11.3 mm within the scintillator of each layer. The spatial resolution and peak-to-peak distance for each location were measured in an 11 x 11 array of flood images. The average measured spatial resolution was 0.25 mm, and the average distance between peaks was 1.0 mm. Through this, it was confirmed that all locations were separated from each other. In addition, because the light signals of all layers were measured separately from each other, the layer of the scintillator that interacted with the gamma rays could be completely separated. When the designed detector is used as a detector in a PET system for small animals, it is considered that excellent spatial resolution and sensitivity can be achieved and image quality can be improved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.608-616
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• 2018

If a general nonlinear system is linearized by the successive multiplication of the 1st and 2nd order systems, then there are four types of poles in this linearized system: the pole of the 1st order system and the equal poles, two distinct real poles, and complex conjugate pair of poles of the 2nd order system. Linear Quadratic (LQ) control is a method of designing a control law that minimizes the quadratic performance index. It has the advantage of ensuring the stability of the system and the pole placement of the root of the system by weighted matrix adjustment. LQ control by the weighted matrix can move the position of the pole of the system arbitrarily, but it is difficult to set the weighting matrix by the trial and error method. This problem can be solved using the characteristic equations of the Hamiltonian system, and if the control weighting matrix is a symmetric matrix of constants, it is possible to move several poles of the system to the desired closed loop poles by applying the control law repeatedly. The paper presents a method of calculating the state weighting matrix and the control law for moving the equal poles with Jordan blocks to two real poles using the characteristic equation of the Hamiltonian system. We express this characteristic equation with a state weighting matrix by means of a trigonometric function, and we derive the relation function (${\rho},\;{\theta}$) between the equal poles and the state weighting matrix under the condition that the two real poles are the roots of the characteristic equation. Then, we obtain the moving-range of the two real poles under the condition that the state weighting matrix becomes a positive semi-finite matrix. We calculate the state weighting matrix and the control law by substituting the two real roots selected in the moving-range into the relational function. As an example, we apply the proposed method to a simple example 3rd order system.