• 제목/요약/키워드: NP-complete

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First-fit 전략을 사용하는 템플럿 패킹 문제를 위한 근사 알고리즘 (An Approximation Algorithm based on First-fit Strategy for Template Packing Problem)

  • 송하주;권오흠
    • 한국멀티미디어학회논문지
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    • 제19권2호
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    • pp.443-450
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    • 2016
  • This paper deals with a kind of packing problem of which the goal is to compose one or more templates which will be used to produce the items of different types. Each template consists of a fixed number of slots which are assigned to the different types of items and the production of the items is accomplished by printing the template repeatedly. The objective is to minimize the total number of produced items. This problem is known to be NP-hard. We present a polynomial time approximation algorithm which has a constant approximation ratio. The proposed algorithm is based on the well-known first-fit strategy.

Minimum Energy Cooperative Path Routing in All-Wireless Networks: NP-Completeness and Heuristic Algorithms

  • Li, Fulu;Wu, Kui;Lippman, Andrew
    • Journal of Communications and Networks
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    • 제10권2호
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    • pp.204-212
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    • 2008
  • We study the routing problem in all-wireless networks based on cooperative transmissions. We model the minimum-energy cooperative path (MECP) problem and prove that this problem is NP-complete. We hence design an approximation algorithm called cooperative shortest path (CSP) algorithm that uses Dijkstra's algorithm as the basic building block and utilizes cooperative transmissions in the relaxation procedure. Compared with traditional non-cooperative shortest path algorithms, the CSP algorithm can achieve a higher energy saving and better balanced energy consumption among network nodes, especially when the network is in large scale. The nice features lead to a unique, scalable routing scheme that changes the high network density from the curse of congestion to the blessing of cooperative transmissions.

COMPLEXITY OF THE SCHEDULING LANGUAGE RSV

  • KIM POK-SON;KUTZNER ARNE;PARK TAEHOON
    • Journal of applied mathematics & informatics
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    • 제20권1_2호
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    • pp.181-195
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    • 2006
  • Resource-constrained project scheduling problems with variant processes can be represented and solved using a logic-based terminological language called RSV (resource constrained project scheduling with variant processes). We consider three different variants for formalizing the RSV-scheduling problem, the optimizing variant, the number variant and the decision variant. Using the decision variant we show that the RSV- problem is NP-complete. Further we show that the optimizing variant (or number variant) of the RSV-problem is computable in polynomial time iff. the decision variant is computable in polynomial time.

Cloning and sequence analysis of Wild Argali short palate, lung and nasal epithelium clone 1 cDNA

  • Shen, Wen;Chen, Kaili;Sun, Yanming;Guo, Haiying;Chen, Dongmei;Cao, Yang
    • Asian-Australasian Journal of Animal Sciences
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    • 제30권5호
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    • pp.736-742
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    • 2017
  • Objective: Experiments were conducted to clone the sequence of Wild Argali short palate, lung and nasal epithelium clone 1 (SPLUNC1) cDNA, and to lay the foundation for further study the biological function of Wild Argali SPLUNC1. Methods: The complete sequence of Wild Argali SPLUNC1 cDNA was generated by rapid amplification of cDNA ends. The entire coding sequence was inserted into the pPIC9K vector and expressed in Pichia pastoris (P. pastoris) GS115. The recombinant SPLUNC1 protein was detected by Western blot and purified by $Ni^{2+}$ chelate affinity chromatography. The test of effect of the protein on Mycoplasma ovipneumoniae (MO) was performed with real-time polymerase chain reaction. Results: The Wild Argali SPLUNC1 cDNA was 1,076 bp with an open reading frame of 768 bp, which encoded a 26.49 kDa protein composed of 255 amino acids. Its amino acid sequence shared 98.4%, 96.9%, 94.5%, 90.2%, 80.8%, 78.4%, 78.3%, 72.5%, 72.3%, 68.8% identity with those of SPLUNC1 cDNA from Ovis aries (accession no. NP_001288334.1), Capra hircus (accession no. XP_005688516.1), Pantholops hodgsonii (accession no. XP_005979709.1), Bos taurus (accession no. NP_776851.1), Felis catus (accession no. XP_006929910.1), Homo sapiens (accession no. NP_001230122.1), Sus scrofa (accession no. NP_001005727.1), Chinchilla lanigera (accession no. NP_001269294.1), Mus musculus (accession no. NP_035256.2), and Rattus norvegicus (accession no. NP_742028.1), respectively. The recombinant protein corresponded to the expected molecular mass of 25.47 kDa as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and it was detected in the supernatant of P. pastoris, and it could be purified. The results from the test of inhibition effect of argali recombinant SPLUNC1 protein on MO showed that the product could inhibit MO very well (p<0.01). Conclusion: The amino acid sequence of Wild Argali SPLUNC1 was different from other organisms. The recombinant SPLUNC1 protein has good biological activity.

최소 빈도수 문자 우선 선택 방법의 3-SAT 다항시간 알고리즘 (A 3-SAT Polynomial Time Algorithm Based on Minimum Frequency Literal-First Selection Method)

  • 이상운
    • 한국인터넷방송통신학회논문지
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    • 제23권1호
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    • pp.157-162
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    • 2023
  • 본 논문은 NP-완전으로 알려진 3-SAT 문제에 대해 O(nm)의 다항시간 알고리즘을 제안하였다. 여기서 n은 3-SAT 수식 f에 포함된 문자수이며, m은 모든 문자의 총 발생 빈도수이다. 제안된 알고리즘은 우선순위롤 정하여 문자의 진리 값을 결정하였다. 하나의 절에 포함된 최소 문자의 수가 1개(k=1)인 문자, k≥2 이고 진리 값이 '0' 또는 '1'만 존재하는 문자, 발생 빈도수가 최소인 문자 우선순위로 진리 값을 결정하였다. 진리 값이 결정된 문자의 r인 절을 삭제하고, 남아 있는 절에서 해당 문자를 삭제하는 방법으로 식을 축소시킨다. 이 과정을 문자 수 l회를 수행하면 주어진 f의 충족 가능 여부를 결정할 수 있다. 이 방법을 적용한 결과 주어진 식 f의 충족 가능 여부를 판단할 수 있었으며, 모든 문자의 진리 값도 결정할 수 있었다. 제안된 알고리즘을 다양한 문제들에 적용한 결과 모든 문제들에서 충족가능 여부를 정확히 결정할 수 있었다. 결국, 제안된 알고리즘은 모든 SAT 문제를 선형시간으로 풀 수 있는 일반화된 알고리즘으로 확장 가능하며, 오랜 숙원이던 P vs. NP 문제를 풀 수 있는 기반을 제공하였다.

Flow-shop Scheduling Problem with Weighted Work-In-Process

  • Yang, Jae-Hwan
    • 한국경영과학회:학술대회논문집
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    • 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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    • pp.193-206
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    • 2005
  • This paper considers a new flow-shop scheduling problem where a different WIP (work-in-process) state has different weight on the duration time. For the two machine case, the recognition version is NP-Complete in the strong sense. Several special cases are solved by different polynomial time algorithms. Finally, we develop a heuristic and provide an upper-bound on relative error which is tight in limit.

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동적 네트워크를 이용한 표면실장기 운영 평가 (The evaluation for the operation surface mounters using a dynamic network)

  • 이달상
    • 한국경영과학회:학술대회논문집
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    • 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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    • pp.570-573
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    • 1996
  • The evaluation test for the operation of rotary type surface mounters which consist of the reel axis, the index table and the X-Y table, has been performed by comparing the new method with the old one in only fields. Because the problem seeking for the optimal operation of rotary type surface mounters, is NP complete, it is almost impossible to get the optimal solutions of large problems. This paper deals with a dynamic network modeling, which can reduce the effort, the cost, and the time used for the performance test of rotary type surface mounters.

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유전 알고리즘을 이용한 블록조립공장의 생산일정계획 (A production schedule with genetic algorithm in block assembly shop)

  • 고시근
    • 경영과학
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    • 제13권1호
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    • pp.1-12
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    • 1996
  • This paper deals with production scheduling of block assembly shop in shipbuilding company. The Objectives of the schedule are leveling of daily total workload and fair assignment of workload to each department of the shop. Optimizing the objectives, we consider some restrictions which consisit of block due dates, workability of each department, and space restriction. We formulate the problem in mathematical form. But the model is too complex to find the optimal solution (the problem is NP-complete) and we use the genetic algorithm to find a good solution.

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Channel Allocation for the Low Earth Orbit Satellite Systems

  • Kim, Soo-Hyun;Kim, Soo-Hyun;Chang, Kun-Nyeong
    • 한국경영과학회지
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    • 제22권4호
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    • pp.37-50
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    • 1997
  • We consider the channel allocation problem for the earth orbit (LEO) satellite systems. This problm is known to be NP-complete and a couple of heuristic algorithms have been developed. In this paper, we convert the problem into a simpler form through the concept of pattern. And we suggest another algorithm based on Simulated Annealing for this simplified problem. The results of performance comparison show that our method works very well. Simulation results are reported.

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GARS : 그리드 환경을 위한 리소스 매핑 알고리즘 (GARS : Resource Mapping Algorithm for Computational Grid Environment)

  • 한상렬;김기형
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2003년도 추계학술발표논문집 (상)
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    • pp.123-126
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    • 2003
  • 이질적인 계산자원들로 구성된 환경에서 독립적인 작업들을 스케줄링하기 위한 최적의 방법을 찾는 것은 NP-Complete 문제로 알려져 있다[3]. 현재까지 이 문제를 풀기 위한 다양한 휴리스틱 스케줄링 방법이 연구되어 왔다[l][4][5][6]. 본 논문에서는 그리드 컴퓨팅 환경을 위한 태스크 매핑 알고리즘을 제안한다. 제안한 알고리즘은 태스크의 완료시간을 계산시간과 통신시간으로 분리하여 노드의 성능과 네트워크의 상태를 감안하여 태스크를 할당하는 네트워크 적응적 매핑 알고리즘이다.

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