• 한국의학물리학회지:의학물리
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• 제31권3호
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• pp.54-62
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• 2020

Dose calculation algorithms play an important role in radiation therapy and are even the basis for optimizing treatment plans, an important feature in the development of complex treatment technologies such as intensity-modulated radiation therapy. We reviewed the past and current status of dose calculation algorithms used in the treatment planning system for radiation therapy. The radiation-calculating dose calculation algorithm can be broadly classified into three main groups based on the mechanisms used: (1) factor-based, (2) model-based, and (3) principle-based. Factor-based algorithms are a type of empirical dose calculation that interpolates or extrapolates the dose in some basic measurements. Model-based algorithms, represented by the pencil beam convolution, analytical anisotropic, and collapse cone convolution algorithms, use a simplified physical process by using a convolution equation that convolutes the primary photon energy fluence with a kernel. Model-based algorithms allowing side scattering when beams are transmitted to the heterogeneous media provide more precise dose calculation results than correction-based algorithms. Principle-based algorithms, represented by Monte Carlo dose calculations, simulate all real physical processes involving beam particles during transportation; therefore, dose calculations are accurate but time consuming. For approximately 70 years, through the development of dose calculation algorithms and computing technology, the accuracy of dose calculation seems close to our clinical needs. Next-generation dose calculation algorithms are expected to include biologically equivalent doses or biologically effective doses, and doctors expect to be able to use them to improve the quality of treatment in the near future.

• Journal of information and communication convergence engineering
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• 제9권5호
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• pp.607-609
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• 2011

In this work, we present solutions of two problems. First, the representation of pattern recognition problem in the standard $T_{nml}$ table of the algorithm estimate calculation was considered. Second, the problem of finding the model, consisting of the optimal parameters of an algorithm was considered. Such procedure is carried out by the selection optimal values of the parameters of extreme algorithms. This serves to reduce the number of calculations in the algorithms of estimate calculation and to increase the quality of recognition process. The algorithmic data base of the developed system was based on mathematical apparatus of pattern recognition.

• 방사성폐기물학회지
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• 제18권1호
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• pp.19-29
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• 2020

This paper gives two graph-based algorithms for radioactive decay computation. The first algorithm identifies the connected components of the graph induced from the given radioactive decay dynamics to reduce the size of the problem. The solutions are derived over the precalculated connected components, respectively and independently. The second algorithm utilizes acyclic structure of radioactive decay dynamics. The algorithm evaluates the reachable vertices of the induced system graph from the initially activated vertices and finds the minimal set of starting vertices populating the entire reachable vertices. Then, the decay calculations are performed over the reachable vertices from the identified minimal starting vertices, respectively, with the partitioned initial value over the reachable vertices. Formal arguments are given to show that the proposed graph inspired divide and conquer calculation methods perform the intended radioactive decay calculation. Empirical efforts comparing the proposed radioactive decay calculation algorithms are presented.

• Journal of Astronomy and Space Sciences
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• 제17권2호
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• pp.249-256
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• 2000

It has been developed to calculate fuel budget for a geostationary communication and broadcasting satellite. It is quite essential that the pre-launch fuel budget estimation must account for the deterministic transfer and drift orbit maneuver requirements. After on-station, the calculation of satellite lifetime should be based on the estimation of remaining fuel and assessment of actual performance. These estimations step from the proper algorithms to produce the prediction of satellite lifetime. This paper concentrates on the fuel estimation method that was studied for calculation of the propellant budget by using the given algorithms. Applications of this method are discussed for a communication and broadcasting satellite.

• 한국초등수학교육학회지
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• 제12권1호
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• pp.1-25
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• 2008

최근 더욱 강조되는 교사의 교수 내용 지식과 관련하여 분수에 관한 연구는 상대적으로 많으나 소수와 관련된 연구는 매우 드물다. 초등수학교육에서 소수가 차지하는 양과 개념적 중요성을 생각해볼 때, 이에 대한 연구가 시급하다. 이에 본 연구는 예비초등교사의 소수연산에 관한 수학 내용 지식, 학생 이해 지식, 교수 방법 지식을 살펴보았다. 분석 결과, 예비교사들은 교과서에 제시된 연산 방법에 관해서는 잘 이해하고 있었으나 승수나 제수가 소수인 경우 연산의 의미는 잘 이해하지 못했다. 학생들의 오류에 대해서는 자연수 관련 오류에 비해 소수점 관련 오류, 분수 관련 오류를 잘 이해하지 못하였다. 교수 방법에 대해서는 알고리즘에 관한 설명이 가장 많았으며, 응답 중 '자연수 연산과 비슷하게 계산하되 소수점에 유의한다.'와 같은 반응이 많아 학생들의 자연수 관련 오류의 원인이 될 가능성을 보였다. 이런 측면에서 본 연구는 예비초등교사교육에서 초등학생들의 오류 유형 및 원인에 대해 더 민감하게 배우고 단순한 알고리즘 이외의 다양한 교수법에 대해서 학습할 기회가 필요하다는 점을 강조한다.

• 상하수도학회지
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• 제12권1호
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• pp.70-80
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• 1998

Many algorithms to find a minimum cost design of water distribution network (WDN) have been developed during the last decades. Most of them have tried to optimize cost only while satisfying other constraining conditions. For this, a certain degree of simplification is required in their calculation process which inevitably limits the real application of the algorithms, especially, to large networks. In this paper, an optimum design method using the Genetic Algorithms (GA) is developed which is designed to increase the applicability, especially for the real world large WDN. The increased to applicability is due to the inherent characteristics of GA consisting of selection, reproduction, crossover and mutation. Just for illustration, the GA method is applied to find an optimal solution of the New York City water supply tunnel. For the calculation, the parameter of population size and generation number is fixed to 100 and the probability of crossover is 0.7, the probability of mutation is 0.01. The yielded optimal design is found to be superior to the least cost design obtained from the Linear Program method by $4.276 million.

• 대한안전경영과학회지
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• 제13권1호
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• pp.133-142
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• 2011

Overhead facility design problem(OFDP) is one of the shortest rectilinear flow network problem(SRFNP)[4]. Genetic algorithm(GA), artificial immune system(AIS), population management genetic algorithm (PM) and greedy randomized adaptive search procedures (GRASP) were introduced to solve OFDP. A path matrix formed individual was designed to represent rectilinear path between each facility. An exchange crossover operator and an exchange mutation operator were introduced for OFDP. Computer programs for each algorithm were constructed to evaluate the performance of algorithms. Computation experiments were performed on the quality of solution and calculations time by using randomly generated test problems. The average object value of PM was the best of among four algorithms. The quality of solutions of AIS for the big sized problem were better than those of GA and GRASP. The solution quality of GRASP was the worst among four algorithms. Experimental results showed that the calculations time of GRASP was faster than any other algorithm. GA and PM had shown similar performance on calculation time and the calculation time of AIS was the worst.

• 한국방사선학회논문지
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• 제17권5호
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• pp.633-640
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• 2023

최근 근접 치료에서 방사선 차폐막을 사용하여 선량 분포를 변조하여 선량을 전달하는 정적 및 동적 변조 근접 치료 방법이 개발됨에 따라 새로운 방향성 빔 세기 변조 근접 치료에 적합한 역방향 치료 계획 및 치료 계획 최적화 알고리즘에서 선량 계산에 필요한 파라미터 및 데이터의 양이 증가하고 있다. 세기 변조 근접 치료는 방사선의 정확한 선량 전달이 가능하지만, 파라미터와 데이터의 양이 증가하기 때문에 선량 계산에 필요한 경과 시간이 증가한다. 본 연구에서는 선량 계산 경과 시간의 증가를 줄이기 위해 그래픽 카드 기반의 CUDA 가속 선량 계산 알고리즘을 구축하였다. 계산 과정의 가속화 방법은 관심 체적의 시스템 행렬 계산 및 선량 계산의 병렬화를 이용하여 진행하였다. 개발된 알고리즘은 모두 인텔(3.7GHz, 6코어) CPU와 단일 NVIDIA GTX 1080ti 그래픽 카드가 장착된 동일한 컴퓨팅 환경에서 수행하였으며, 선량 계산 시간은 디스크에서 데이터를 불러오고 전처리를 위한 작업 등의 추가 적으로 필요한 시간은 제외하고 선량 계산 시간만 측정하여 평가하였다. 그 결과 가속화된 알고리즘은 CPU로만 계산할 때보다 선량 계산 시간이 약 30배 단축된 것으로 나타났다. 가속화된 선량 계산 알고리즘은 적응방사선치료와 같이 매일 변화되는 어플리케이터의 움직임을 고려하여 새로운 치료 계획을 수립해야 하는 경우나 동적 변조 근접 치료와 같이 선량 계산에 변화되는 파라미터를 고려해야 하는 경우 치료 계획 수립 속도를 높일 수 있을 것으로 판단된다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제3권2호
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• pp.121-135
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• 1999

This paper studies the problem of inverting minimal path sets to obtain minimal cut sets for complex system. We describe efficiency of inversion algorithm by the use of boolean algebra and we develop inclusion-exclusion algorithm and pivotal decomposition algorithm for reliability calculation of complex system. Several examples are illustrated and the computation speeds between the two algorithms are undertaken.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1027-1028
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• 2011

In this paper, three reliability calculation algorithms: Monte Carlo Simulation (MCS), Reliability Index Approach (RIA), and Sensitivity-based Monte Carlo Simulation (SMCS) are studied. Their efficiency and accuracy are validated by analytic test functions.