• Journal of the Korea Society of Computer and Information
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• v.18 no.12
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• pp.75-82
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• 2013

This paper proposes a $O(n^2)$ polynomial time algorithm to obtain optimal solution for Traveling Salesman problem that is a NP-complete because polynomial time algorithm has been not known yet. The biggest problem in a large-scale Traveling Salesman problem is the fact that the amount of data to be processed is $n{\times}n$, and thus as n increases, the data increases by multifold. Therefore, this paper proposes a methodology by which the data amount is first reduced to approximately n/2. Then, it seeks a bi-directional route at a random point. The proposed algorithm has proved to be successful in obtaining the optimal solutions with $O(n^2)$ time complexity when applied to TSP-1 with 26 European cities and TSP-2 with 46 cities of the USA. It could therefore be applied as a generalized algorithm for TSP.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.151-158
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• 2023

The researchers entirely focused on meta-heuristic method for generalized assignment problem(GAP) that is known as NP-hard problem because of the optimal solution within polynomial time algorithm is unknown yet. On the other hand, this paper proposes a heuristic greedy algorithm with rules for finding solutions. Firstly, this paper reduces the weight matrix of original data to w_ij ≤ b_i/l in order to n jobs(items) pack m machines(bins) with l = n/m. The maximum profit of each job was assigned to the machine for the reduced data. Secondly, the allocation was adjusted so that the sum of the weights assigned to each machine did not exceed the machine capacity. Finally, the k-opt swap optimization was performed to maximize the profit. The proposed algorithm is applied to 50 benchmarking data, and the best known solution for about 1/3 data is to solve the problem. The remaining 2/3 data showed comparable results to metaheuristic techniques. Therefore, the proposed algorithm shows the possibility that rules for finding solutions in polynomial time exist for GAP. Experiments demonstrate that it can be a P-problem from an NP-hard.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.6
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• pp.487-490
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• 2001

In this paper, we realize a system that moves a cursor with a finger using the circular pattern vector algorithm that in one of the image analysis algorithms. To apply this algorithm, we use central point of the biggest circle among the various circles that recognize the image of the hand , and find out the pointing finger by looking for the distance of the outline of the hand from the central point. The horizontal direction of the cursor on the display is controlled by converting the direction of the pointing finger to the analysis of the plane corrdinate. Because of setting up only one camera of the upper, the middle and the lower discretely. On account of the discrete movement of the cursor of the vertical direction, we move th cursor to the objective, which the user wants. by expanding the local are to the whole area.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.137.2-137.2
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• 2011

규표(圭表)는 남중하는 해의 그림자를 측정해 일 년의 길이와 절기를 알아내기 위한 관측 기기이다. 규표에 대한 우리 역사 기록에 따르면 조선시대에 8척과 40척 크기의 규표를 만들어 사용한 것으로 알려져 있다. 세종대에 간의대 서쪽에 설치한 40척 규표에 대해서는 그 구조와 크기가 상세히 기록되어 있지만 8척 규표에 대해서는 명종대의 관측 사실만이 남아있을 뿐이다. 8척 규표에 관한 국내 외 문헌과 중국에 남아 있는 유물을 조사하여 조선의 8척 규표 모델을 새롭게 복원하였다. 복원한 8척 규표는 주척(周尺, 1척=20.7cm)을 기준으로 규 21척, 표 8척의 크기이다. 오석으로 만든 규면에는 16척 길이의 눈금을 1분(2.07cm) 단위로 새겨놓았다. 청동으로 만든 표의 꼭대기에는 그림자를 명확히 나타내기 위해 길이 2척, 지름 1.2cm의 횡량(橫樑)을 설치하였다. 또한 횡량의 그림자를 정확하게 측정하기 위해 규면에 설치할 영부(影符)도 함께 연구 복원하였다. 규면에 새겨진 못(池)과 물홈(水渠)의 모양은 한국과 중국의 천문유물에 남아 있는 여러 자료와 구조적 기능을 고려해 결정하였다. 지금까지 국내에서 복원된 규표는 8척 규표에 대한 문헌 자료가 부족했기 때문에 40척 규표의 구조를 축소해서 만들어왔다. 이번에 복원한 조선의 8척 규표는 40척 규표의 축소 모형이 아닌 새로운 모델을 연구하여 제작한 것으로 한국천문연구원 앞뜰 간의 서편에 설치하였다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.38-43
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• 2008

The purpose of this study is to secure reasonable transportation infrastructure stock for enhancing national competitiveness in Korea. National competitiveness may be defined as a country's overall capacity to create the most effective social structure, institutions and policies that allow her company within the national boundary to be more competitive in the world market. If Korea's transportation infrastructure stock is not sufficient and a connection among transportation facilities is not efficient, we should pay the social and economic cost. As a result, we worry that national competitiveness may drop. Some methods to maintain or to increase the national investment for transportation infrastructure that are suggested from this study are as follows: Firstly, we need to operate the Spcial Account for Traffic Facilities. Secondly, the investment should be focused on the facilities and districts in needs. Thirdly, PFI (private finance initiative) policy should be aimed at investing for the highly economic-valued projects.

• The Transactions of the Korea Information Processing Society
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• v.6 no.12
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• pp.3703-3709
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• 1999

We propose a new approach to reconstruct the surface shape of an object from a shaded image. We use genetic algorithm instead of gradient descent algorithm which is apt to take to local minima and also proposes genetic representation and suitable genetic operators for manipulating 2-D image. And for more effective execution, we suggest hierarchical process to reconstruct minutely the surface of an object after coarse and global reconstruction. A modified Lambertian illumination model including the distance factor was herein adopted to get more reasonable result and an experiment was performed with synthesized and real images to demonstrate the devised method, of which results show the usefulness of our method.

• Journal of Korean Society of Transportation
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• v.17 no.2
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• pp.137-147
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• 1999

This paper studies on the optimal bus network design in the framework of the set covering theory. The theory enables to cover passenger's loading and alighting areas as the set, and maximize the covering set as much as possible. In other words, it calculates the minimal set of the bus routes for covering whole bus passengers demand. After the optimal set of the bus routes is generated by the set covering theory, multimodal traffic equilibrium assignment is used for evaluating the generated set in terms of passenger's mode and route choice behavior. Whilst most previous works on it have been based on analyzing a specific route in a limited area, this study seeks to optimize the whole bus network.

• Journal of Aerospace System Engineering
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• v.18 no.2
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• pp.71-78
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• 2024

During the initial thermal design process, determining the thermal effect of various design variables in a complex orbital thermal environment is time-consuming. To save time in the initial design phase, it is necessary to quickly derive optimal design parameters and predict the temperature. To address these challenges, Veritrek, a software specialized in optimal design using a reduced-order model (ROM), was released in 2018. In this paper, we utilized the Veritrek software to build a reduced-order model, conduct sensitivity analysis, and perform optimal design analysis for a graphite sheet-based cryogenic cooler thermal control system. The goal was to determine the optimal design values for the number of graphite sheet layers, radiator area, and thickness that would meet the allowable temperature of the cryogenic cooler.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.5
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• pp.275-282
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• 2018

Using isogeometric analysis(IGA) gives more accurate results for higher order mode in eigenvalue problem than using the finite element method(FEM). This is because the FEM has $C^0$ continuity between elements, whereas IGA guarantee $C^{P-1}$ between elements for p-th order basis functions. In this paper, a mode based reduced model is constructed by using IGA and dynamic behavior analysis is performed using this advantage. Craig-Bampton(CB) method is applied to construct the reduced model. Several numerical examples were performed to compare the eigenvalue analysis results for various order of element basis function by applying the IGA and FEM to simple rod analysis. We have confirmed that numerical error increases in the higher order mode as the continuity between elements decreases in the IGA by allowing internal knots multiplicity. The accuracy of the solution can be improved by using the IGA with high inter-element continuity when high-frequency external force acts on the reduced model for dynamic behavior analysis.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.263-269
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• 2014

In this paper, I disprove Hadwiger conjecture of the vertex coloring problem, which asserts that "All $K_k$-minor free graphs can be colored with k-1 number of colors, i.e., ${\chi}(G)=k$ given $K_k$-minor." Pursuant to Hadwiger conjecture, one shall obtain an NP-complete k-minor to determine ${\chi}(G)=k$, and solve another NP-complete vertex coloring problem as a means to color vertices. In order to disprove Hadwiger conjecture in this paper, I propose an algorithm of linear time complexity O(V) that yields the exact solution to the vertex coloring problem. The proposed algorithm assigns vertex with the minimum degree to the Maximum Independent Set (MIS) and repeats this process on a simplified graph derived by deleting adjacent edges to the MIS vertex so as to finally obtain an MIS with a single color. Next, it repeats the process on a simplified graph derived by deleting edges of the MIS vertex to obtain an MIS whose number of vertex color corresponds to ${\chi}(G)=k$. Also presented in this paper using the proposed algorithm is an additional algorithm that searches solution of ${\chi}^{{\prime}{\prime}}(G)$, the total chromatic number, which also remains NP-complete. When applied to a $K_4$-minor graph, the proposed algorithm has obtained ${\chi}(G)=3$ instead of ${\chi}(G)=4$, proving that the Hadwiger conjecture is not universally applicable to all the graphs. The proposed algorithm, however, is a simple algorithm that directly obtains an independent set minor of ${\chi}(G)=k$ to assign an equal color to the vertices of each independent set without having to determine minors in the first place.