• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11C
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• pp.140-147
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• 2001

In this paper, we propose a scheme of calculating resources\` costs for precomputation in QoS routing schemes. This scheme is effective in respect to the g1oba1 network utilization and the balanced use of network resources. We also propose a QoS routing scheme for transit and intra traffic in a large scale of domain-based network. For a domain in the network, the routing scheme first precomputes multiple paths between all pairs of ingress and egress border routers while considering balancing of the expected load and then selects paths with the probability of path selection. We, therefore, expect that the paths are better than any other paths in respect to reserving the network resources on paths. The routing scheme combines inter and intra domain routings seamlessly and uses the same cost calculation scheme. And for analysis of a load balancing cost calculation proposed a simulation is done.

• The KIPS Transactions:PartC
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• v.9C no.5
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• pp.671-678
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• 2002

In this paper, we propose hierarchical inter-domain load balanced QoS routing in a large scale of network. And a scheme of calculating resources'costs for precomputation schemes in hierarchical routing is proposed, and a scheme for selecting a path among multiple precomputed paths is proposed. We also propose a QoS routing scheme for transit and intra traffic in a large scale of domain-based network. For a domain in the network, the routing scheme first precomputes K multiple paths between all pairs of ingress and egress border routers while considering balancing of the expected load then selects paths with the probability of path selection. The routing scheme combines inter and intra domain routings seamlessly and uses the same cost calculation scheme. And these schemes make possible both global network resources' utilization and also load balancing.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.385-386
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• 2009

활성 윤곽선 모델은 스네이크 모델이라고도 하며 영상에서 물체의 경계를 검출하기위한 효과적인 방법으로 사용되고 있다. 본 논문에서는 초기 윤곽선 문제와 효과적인 경계선 검출을 위해 다해상도 기반의 유전자 알고리즘을 이용한 활성 윤곽선 모델을 제안한다. 입력영상의 해상도를 영상 피마리드 기법으로 저해상도로 축소시키고 초기 윤곽선을 설정한다. 설정된 윤곽선상의 연속된 두 좌표를 유전인자로 선택하고, 유전 연산자를 적용하여 물체의 경계를 찾아간다. 경계가 검출된 저해상도 영상을 단계적으로 확대하여, 보간될 영역의 국부적 활성 윤곽선 에너지를 계산하여 최소 에너지를 갖는 위치에 새로운 윤곽선 좌표를 삽입하여 경계를 형성한다. 제안된 방법은 초기 윤곽선의 위치에 상관없이 경계선을 검출했으며, 형태가 복잡한 물체의 경우에도 효과적으로 경계선을 검출하고 계산 복잡도를 감소시켰다.

• Progress in Medical Physics
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• v.13 no.3
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• pp.149-155
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• 2002

Recent advances in radiation transport algorithms, computer hardware performance, and parallel computing make the clinical use of Monte Carlo based dose calculations possible. To compare the speed and accuracies of dose calculations between different developed codes, a benchmark tests were proposed at the XIIth ICCR (International Conference on the use of Computers in Radiation Therapy, Heidelberg, Germany 2000). A Monte Carlo treatment planning comprised of 28 various Intel Pentium CPUs was implemented for routine clinical use. The purpose of this study was to evaluate the performance of our system using the above benchmark tests. The benchmark procedures are comprised of three parts. a) speed of photon beams dose calculation inside a given phantom of 30.5 cm$\times$39.5 cm $\times$ 30 cm deep and filled with 5 ㎣ voxels within 2% statistical uncertainty. b) speed of electron beams dose calculation inside the same phantom as that of the photon beams. c) accuracy of photon and electron beam calculation inside heterogeneous slab phantom compared with the reference results of EGS4/PRESTA calculation. As results of the speed benchmark tests, it took 5.5 minutes to achieve less than 2% statistical uncertainty for 18 MV photon beams. Though the net calculation for electron beams was an order of faster than the photon beam, the overall calculation time was similar to that of photon beam case due to the overhead time to maintain parallel processing. Since our Monte Carlo code is EGSnrc, which is an improved version of EGS4, the accuracy tests of our system showed, as expected, very good agreement with the reference data. In conclusion, our Monte Carlo treatment planning system shows clinically meaningful results. Though other more efficient codes are developed such like MCDOSE and VMC＋＋, BEAMnrc based on EGSnrc code system may be used for routine clinical Monte Carlo treatment planning in conjunction with clustering technique.

• Journal of radiological science and technology
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• v.31 no.1
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• pp.89-95
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• 2008

The quality correction factor for used beam and qualities is strongly required for clinical dosimetry by TRS-398 protocol of IAEA. In this study the quality correction factors for a commercial plane-parallel ionization chamber in high energy electron beams were calculated by Monte Carlo code(DOSRZnrc/EGSnrc). In comparison of quality correction factor, the difference between this study and TRS-398 were within 1% in 5-20 MeV. In case of 4MeV the difference was 1.9%. As an independent method of determination of quality correction factor this study can be applied to evaluate values in the protocol or calculate the factor for a new chamber.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.5
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• pp.10-17
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• 2003

Dynamic stability is critically required to stabilize an airship which is statically unstable. Numerical computations were performed in order to support and confirm the foced oscillation wind tunnel tests. To analyze the low-speed flow filed around the airship, a low-Mach number preconditioned method was applied. Using two computation methods, variations of the dynamic damping coefficients were examined. Numerical results show that it is dynamically stable for three directional moments, but unstable for normal or side force. It is revealed that the damping coefficients are more sensitive to the direction of the angular rate than the angle of attack or the magnitude og angular rate.

• Journal of Radiation Protection and Research
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• v.3 no.1
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• pp.29-32
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• 1978

A shielding calculation has been carried out for a storage vault of $5292(42{\times}42{\times}3)$ waste drums in which the mixed radioactive gamma-emitters are contained. The required ordinary concrete shielding thickness seems to be approximately 50cm. The results in terms of dose rate for polyenergy gammas appear to be considerably higher than those of the averaged energy gamma.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.3
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• pp.26-34
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• 1999

A new silicon-based IC interconnect transmission line parameter extraction methodology is presented and experimentally examined. Unlike the PCB or MCM interconnects, a dominant energy propagation mode in the silicon-based IC interconnects is not quasi-TEM but slow wave mode(SWM). The transmission line parameters are extracted taking the silicon substrate effect (i.e., slow wave mode) into account. The capacitances are calculated considering silicon substrate surface as a ground. Whereas the inductances are calculated by using an effective dielectric constant. In order to verify the proposed method, test patterns were designed. Experimental data have agreement within 10%. Further, crosstalk noise simulation shows excellent agreements with the measurements which are performed with high-speed time domain measurement ( i.e., TDR/TDT measurements) for test pattern, while RC model or RLC model without silicon substrate effect show about 20~25% underestimation error.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.2 s.117
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• pp.191-198
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• 2007

The electromagnetic coupling between transmission lines in PCB design can degrade the performance of equipment operations. The coupling phenomenon is caused by electromagnetic fields generated by the currents on the transmission lines and the risers. In this paper, an improved method of crosstalk analysis for bent coupled lines on a PCB is proposed and investigated. In the previous cascading method combined with circuit-concept approach, bent coupled lines are devided into sections and each section is represented by ABCD matrix and then they are cascaded. In the proposed method, the crosstalk of bent coupled lines is calculated by the modified circuit-concept approach, where the coupled region is not restricted to the region projected by a generator line on a receptor line but is the total length of receptor line in calculating the forcing terms. Finally, the accuracy of the proposed approach is verified by comparing the calculated results with the measured ones for several bent coupled-line examples.

• 전기의세계
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• v.31 no.11
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• pp.749-757
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• 1982

본고의 내용은 다음과 같다. 1. Raft기초의 비전도의 원리 2. 상판 Beam설계 3. 배근계산 4. 계산예