• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2005.05a
• /
• pp.768-772
• /
• 2005

TSP(Traveling Salesman Problem) has been a nagging NP-complete problem to test almost every algorithmic idea in combinatorial optimization in vain. The main bottleneck is how to get the integer results {0,1} and to avoid sub-tours. We suggest simple and practical method in two steps. Firstly for every node, an initial Hamiltonian cycle us produced on the nearest neighbour concept. The node with nearest distance is to be inserted to form a increased feasible cycle. Secondly we improve the initial solution by exchanging 2 cuts of the grand tours. We got practical results within 1 from the optimum in 30 minutes for up to 200 nodes problems. TSP of real world type might be tackled practically in our formulation.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.1
• /
• pp.161-166
• /
• 1997

The blocks world is the primary problem domain in the artificial intelligence. Many planners have been developed in domain-independent. Gupta de fined the deadlock in the blocks world, and he proved that decision making in t he blocks world is NP-Complete problem. In this paper the properties of the dea dlock are analyzed, and a heuristic algorithms which can handle the deadlock of the Gupta's nondeterministic algorithm is proposed.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.17 no.4
• /
• pp.155-161
• /
• 2017

This paper suggests polynomial time solution algorithm for Sudoku puzzle problem. This problem has been known NP (non-deterministic polynomial time)-complete. The proposed algorithm set the initial value of blank cells to value range of [$1,2,{\cdots},9$]. Then the candidate set values in blank cells deleted by preassigned clue in row, column, and block. We apply the basic rules of Stuart, and proposes two additional rules. Finally we apply binary backtracking(BBT) technique. For the experimental Sudoku puzzle with various categories of solution, the BBT algorithm can be obtain all of given Sudoku puzzle regardless of any types of solution.

• Journal of Internet Computing and Services
• /
• v.5 no.5
• /
• pp.129-138
• /
• 2004

In the telecommunications network, multicasting is widely used recently. Multicast tree problem is modeled as the NP-complete Steiner problem in the networks. In this paper, we study algorithms for finding efficient multicast trees with hop and node degree constraints. Multimedia service is an application of multicasting and it is required to transfer a large volume of multimedia data with QoS(Quality of Service). Though heuristics for solving the multicast tree problems with one constraint have been studied. however, there is no optimum algorithm that finds an optimum multicast tree with hop and node degree constraints up to now. In this paper, an approach for finding an efficient multicast tree that satisfies hop and node degree constraints is presented and the experimental results explain how the hop and node degree constraints affect to the total cost of a multicast tree.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.1 no.1
• /
• pp.16-28
• /
• 1991

Knapsack public-key cryptosystems are based on the knapsack problem which is NP-complete. aii of the knapsack problem, are known to be insecure. However, the Chor and Rivest knapsack cryptosystem based on arithmetic in finite field is secure against all known cryptosystem based on arithmetic in a finite field is secure against all known cryptanalytic attacks. We suggest a new msthod of attack on knapsack cryptosystem which is based on the relaxation of a quadratic 0-1 integer optimization problem. We show that under certain condirions some bits of the solution of knapsack problem can be determined by using persistency property of linear relaxation. Also we propose a new Chor-Rivest system, this new cryptosystem reduces the number of calculation of discrete logarithms which are necessary for the implemention in a multi-user system.

• Journal of the Korea Society of Computer and Information
• /
• v.19 no.11
• /
• pp.175-181
• /
• 2014

This paper suggests O(m) polynomial time heuristic algorithm to obtain the solution for the driver scheduling problem, DSP, that has been classified as NP-complete problem. The proposed algorithm gets the initial assignment of n minimum number of drivers from given m schedules. Nextly, this algorithm gets the minimum total time (TC) using 5 rules of swap and insert for decrease of over times (OT) and idle times (IT). Although this algorithm is a heuristic polynomial time algorithm with O(m) time complexity rules to be find a optimal (or approximate) solution, this algorithm is equal to metaheuristic methods for the 5 experimental data. To conclude, this paper shows the DSP is not NP-complete problem but Polynomial time (P)-problem with polynomial time rules.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.22 no.4
• /
• pp.95-102
• /
• 2022

This paper proposed a linear time algorithm for a three-partition problem(TPP) in which a polynomial time algorithm is not known as NP-complete. This paper proposes a backtracking method that improves the problems of not being able to obtain a solution of the MM method using the sum of max-min values and third numbers, which are known polynomial algorithms in the past. In addition, the problem of MM applying the backtracking method was improved. The proposed algorithm partition the descending ordered set S into three and assigned to the forward, backward, and best-fit allocation method with maximum margin, and found an optimal solution for 50.00%, which is 5 out of 10 data in initial allocation phase. The remaining five data also showed performance to find the optimal solution by exchanging numbers between surplus boxes and shortage boxes at least once and up to seven times. The proposed algorithm that performs simple allocation and exchange optimization with less O(k) linear time performance complexity than the three-partition m=n/3 data, and it was shown that there could be a polynomial time algorithm in which TPP is a P-problem, not NP-complete.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.5C
• /
• pp.422-434
• /
• 2002

We propose 3-layered hierarchical fiber-optic backbone transmission network composed of B-DCS, Backbone ring, Edge ring for efficient transmission of high capacity traffic and consider design method to ensure network survivability of each layer at affordable cost. Mathematical ring-construction cost minimization using MIP(Mixed Integer Programming) models results in NP-complete problem. So, it is hard to solve it within reasonable computing time. on a large-scale network. Therefore we develop heuristic algorithms solving WSCAP(Working and Spared Channel Assignment Problem) for B-DCS, MRLB(Multi-Ring Load Balancing) problem for Backbone ring, and ORLB(Overlayed Ring Load Balancing) problem for Edge ring and show their usefulness through case study.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.9
• /
• pp.2311-2319
• /
• 1999

We present two heuristic algorithms for the task allocation problem (NP-complete problem) in parallel computing. The problem is to find an optimal mapping of multiple communicating tasks of a parallel program onto the multiple processing nodes of a distributed-memory multicomputer. The purpose of mapping these tasks into the nodes of the target architecture is the minimization of parallel execution time without sacrificing solution quality. Many heuristic approaches have been employed to obtain satisfactory mapping. Our heuristics are based on genetic algorithms and simulated annealing. We formulate an objective function as a total computational cost for a mapping configuration, and evaluate the performance of our heuristic algorithms. We compare the quality of solutions and times derived by the random, greedy, genetic, and annealing algorithms. Our experimental findings from a simulation study of the allocation algorithms are presented.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.1
• /
• pp.207-215
• /
• 2015

This paper proposes a solution-yielding linear time algorithm to NP-complete Sudoku, to which no polynomial time algorithm has been proposed. The proposed algorithm is performed on blocks in the descending order of the number of clues they contain. It firstly determines all numbers that could possibly occur in the blank rows and columns of each block. By deriving an intersecting value of corresponding rows and columns, it assigns the final number for each blank. When tested on the traditional $9{\times}9$ Sudoku, the proposed algorithm has succeeded in obtaining the solution through performance of 9 times, the exact number of the blocks. Test results on modified Jigsaw Sudoku (9 blocks) and Hypersudoku (13 blocks) also show its success in deriving the solutions by execuring 9 and 13 times respectively. Accordingly, this paper proves that the Sudoku problem is in fact P-problem.