• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.4
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• pp.165-170
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• 2023

This paper proposes an algorithm that can obtain a solution with linear time for a set cover problem(SCP) in which there is no polynomial time algorithm as an NP-complete problem so far. Until now, only heuristic greed algorithms are known to select sets that can be covered to the maximum. On the other hand, the proposed algorithm is a competitive algorithm that applies an inclusion-exclusion principle rule to N nodes up to 2nd or 3rd in the maximum number of elements to obtain a set covering all k nodes, and selects the minimum cover set among them. The proposed algorithm compensated for the disadvantage that the greedy algorithm does not obtain the optimal solution. As a result of applying the proposed algorithm to various application cases, an optimal solution was obtained with a polynomial time of O(kn²).

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.185-191
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• 2023

To the exact cover problem that remains NP-complete to which no polynomial time algorithm is made available, this paper proposes a linear time algorithm that yields an optimal solution. The proposed algorithm makes use of the set cover problem's major feature which states that "no identical element shall be included in more than one covering set". To satisfy this criterion, the proposed algorithm initially selects a subset with the minimum cardinality and deletes those that contain the cardinality identical to that of the selected subset. This process is repeatedly performed on remaining subsets until the final solution is obtained. Provided that the solution is unattainable, it selects subsets with the maximum cardinality and repeats the same process. The proposed algorithm has not only obtained the optimal solution with ease but also proved its wide applicability on N-queens problems, hence disproving the NP-completeness of the exact cover problem.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.183-191
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• 2011

This paper suggests emergency medical service vehicle (ambulance) algorithm when the emergency patient occurs in order to be sufficient the maximum permission time T of arrival about all sectors in one city that is divided in the various areas. This problem cannot be solved in polynomial times. One can obtains the solution using the integer programming. In this paper we suggest vertex set (or dominating set) algorithm and easily decide the location of ambulances. The core of the algorithm decides the location of ambulance is to the maximum degree vertex among the neighborhood of minimum degree vertex. For the 33 sectors Ostin city in Texas, we apply $3{\leq}T{\leq}20$ minutes. The traditional set cover algorithm with integer programming cannot obtains the solution in several T in 18 cases. But, this algorithm obtains solution for all of the 18 cases.

• Journal of the Korea Society of Computer and Information
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• v.19 no.3
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• pp.109-117
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• 2014

This paper revises the Quine-McCluskey Algorithm to circuit minimization problems. Quine-McCluskey method repeatedly finds the prime implicant and employs additional procedures such as trial-and-error, branch-and-bound, and Petrick's method as a means of circuit minimization. The proposed algorithm, on the contrary, produces an implicant chart beforehand to simplify the search for the prime implicant. In addition, it determines a set cover to streamline the search for $1^{st}$ and $2^{nd}$ essential prime implicants. When applied to 3-variable and 4-variable experimental data, the proposed algorithm has indeed proved to obtain the optimal solutions much more simply and accurately than the Quine-McCluskey method.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.684-689
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• 1998

전기출력 150 MWe(열출력 392 MWth)의 U-Zr 이원합금핵연료 사용 소형노심인 액채금속로 KALIMER 98.03 설계 노심에 대하여 열수력 특성을 분석하고, 그 결과를 97.07 설계 노심의 열수력 설계특성과 비교.분석하였다. 분석을 위해서 냉각재 유량배분 계산에 ORFCE-F, 유량배분에 따를 온도계산에는 ORFCE-T를 사용하였는데, 이들은 현재 KALIMER 개발의 개념설계 초기 단계에서 사용하고 있는 모듈이다. 열수력 특성 분석은 먼저 각 집합체의 출력과 핵연료봉의 최고 선출력에 따라 유량그룹을 설정하고, 각 집합체의 최고온도 연료봉에 대하여 냉각재 온도, 피복관 중심온도, 핵연료 중심온도 등을 계산하는 방식으로 수행한다 열수력 특성분석 결과 98.03 설계 노심이 97.07 설계 노심에 비해 노심내 출력분포가 더욱 평탄화 되어, 노심 유량영역은 16개에서 11개로 감소되었고, 그에 따를 온도계산에서도 피복관 중심에서의 2$\sigma$ 온도가 6$65^{\circ}C$에서 628$^{\circ}C$로 낮아지는 둥 매우 향상된 설계임을 알 수 있었다.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.262.1-262
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• 2002

• Korean Journal of Materials Research
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• v.4 no.3
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• pp.357-363
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• 1994

The irradiation growth of the Zircaloy-4 cladding in the KOFA fuel loaded in the Kori-2 nuclear plant was measured to evaluate the irradiation growth behavior and to be compared with that of the Siemens cladding having different manufacturing process. Due to the partial recrystallization by final heat treatment, the KOFA Zircaloy-4 cladding showed a two step irradiation growth behavior such as the growth saturation and the accerlation which is typical of the fully annealed Zircaloy cladding. The difference in the measured irradiation growth rate between the KOFA and the Siemens cladding could be explained by the difference in the cladding texture which depends on the manufacturing process. From the measured irradiation growth data of Kori-2 KOFA fuel, a two-step irradiation growth model of the KOFA Zircaloy-4 cladding was derived, the accuracy of which can be more clearly verified as the measured data of the irradiation growth are accumulated in the future.

• Nuclear Engineering and Technology
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• v.15 no.4
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• pp.248-255
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• 1983

The thermal analysis on the spent fuel shipping cask for a PWR fuel assembly is performed. Under the normal and fire-accident conditions the temperature distribution through a multilayer cask calculated in compliance with 10 CFR Part 71. A KNU 5&6 spent fuel assembly is assumed to be the decay heat source, which has the maximum discharge turnup of 45, 000MWD/MTU and has been stored in the spent fuel storage pool for 300 days. As a result of thermal analysis, the maximum cladding temperature in case of dry cavity under fire-accident conditions is calculated to be 455$^{\circ}C$. This value is much less than the limiting value specified in 10 CFR Part 50.46. It indicates that no fuel rod cladding rupture could occur under fire-accident conditions. It was also found that no melting of lead would take place in the major shield region.

• Journal of the Korea Society of Computer and Information
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• v.18 no.5
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• pp.113-120
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• 2013

This paper proposes an algorithm that proves an NP-complete 4-color theorem by employing a linear time complexity where $O(n)$. The proposed algorithm accurately halves the vertex set V of the graph $G=(V_1,E_1)$ into the Maximum Independent Set (MIS) $\bar{C_1}$ and the Minimum Vertex Cover Set $C_1$. It then assigns the first color to $\bar{C_1}$ and the second to $\bar{C_2}$, which, along with $C_2$, is halved from the connected graph $G=(V_2,E_2)$, a reduced set of the remaining vertices. Subsequently, the third color is assigned to $\bar{C_3}$, which, along with $C_3$, is halved from the connected graph $G=(V_3,E_3)$, a further reduced set of the remaining vertices. Lastly, denoting $C_3$ as $\bar{C_4}$, the algorithm assigns the forth color to $\bar{C_4}$. The algorithm has successfully obtained the chromatic number ${\chi}(G)=4$ with 100% probability, when applied to two actual map and two planar graphs. The proposed "four color algorithm", therefore, could be employed as a general algorithm to determine four-color for planar graphs.

• Korean Journal of Materials Research
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• v.4 no.4
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• pp.445-452
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• 1994

Three-axial deformation behavior of the Zircaloy cladding tube under the irradiation condition of the fuel in pressurized water reactor can be analyzed by the anisotropy in the creep and the irra- diation growth, which depends on the texture parameter. A methodology to evaluate the impact of the anisotropic creep and irradiation growth on the strain in each axial direction of the cladding tube has been proposed. Based on the measured strains after irradiation and predicted ones with the help of a fuel performance analysis code, it is found that a tangential strain of the cladding tube is caused mainly by the creep, whereas a axial strain of the cladding is caused mainly by the irradiation growth but with a considerable contribution of the creep at low irradiation.