B01

• I am a researcher in the field of electric power and energy. I am researching mechanisms to maximize the introduction of renewable energy sources on the premise of ensuring safety, stable supply, economic efficiency, and environmental conservation. One of the issues in increasing the introduction of renewable energy sources is the degradation of power quality, which adversely affects social life. In this presentation, the mechanism and countermeasures for power quality degradation caused by renewable energy source will be described, and research to expand the amount of renewable energy sources that can be introduced will be introduced.

  2022.11.28 Mon. 10:00-12:00

  32nd CoRe Seminar
  Speaker :IIOKA, Daisuke (Chubu U., Group B01) Title :Development of electric power system based mainly on renewable energy sources Sumarry :
• In this talk, we introduce a Python library for solving combinatorial reconfiguration problems, which is under development in our project. The library is based on graphillion, a subgraph enumeration library. It can solve combinatorial reconfiguration problems for families of sets that can be represented by graphillion. We also introduce the algorithm used in the library.

  2022.07.25 Mon. 15:00-17:00

  28th CoRe Seminar
  Speaker :KAWAHARA, Jun (Kyoto U., Group B01) Title :Reconfillion: a combinatorial reconfiguration solver Sumarry :
• Enumerating subgraphs of a given graph is a fundamental task in computer science. Since the number of subgraphs can be exponentially larger than the input graph size, it is not practical to list all subgraphs one by one. To overcome the difficulty, we focus on implicit enumeration algorithms. Such an algorithm constructs a decision diagram (DD) representing the set of subgraphs instead of explicitly enumerating the subgraphs. In this talk, we introduce recent studies on implicit subgraph enumeration using DDs.

  2022.05.30 Mon. 15:00-17:00

  25th CoRe Seminar
  Speaker :NAKAHATA, Yu (NAIST, Group C01) Title :Implicit subgraph enumeration using decision diagrams Sumarry :
• In this talk, we give an example that combinatorial reconfiguration appears in industry, specifically power distribution systems. A power distribution network is designed as supplying electricity via multiple numbers of routes for redundancy. For example, the Japan standard benchmark model of power distribution networks has approximately 10^{58} alternatives for the choice of network configurations. Even the computation of a single optimal network configuration among them is out of reach. Furthermore, even if we may compute a single optimal network configuration, we need to find a switching procedure to reconfigure the current configuration to the optimal one so that any power failure does not occur during the transformation. This is exactly the situation of combinatorial reconfiguration. In this talk, we will explain the situation in power distribution systems, our reconfiguration algorithm, and experimental results. In addition, we will also explain optimization variant of reconfiguration problems, which is a more practical problem setting.

  2022.4.11 Mon. 15:00-17:00

  22nd CoRe Seminar
  Speaker :SUZUKI, Akira (Tohoku U., Group B01) Title :Optimization variant of reconfiguration applied to power distribution systems Sumarry :
• Propositional satisfiability testing (SAT) problems and SAT solvers have been studied for over 50 years. In particular, since 2000, the performance of SAT solvers has improved dramatically, and SAT technology is attracting attention as a fundamental technology for inference. In this presentation, we will explain SAT solvers in the following order: its recent topics, its improvements in performance, its utilization techniques, and SAT-based constraint programming systems. 

  2021.07.05 Mon. 10:00-12:00

  13th CoRe Seminar
  Speaker :SOH, Takehide (Kobe U., Group B01) Title :Latest trends and utilization techniques of SAT solvers Sumarry :
• Sorting is one of the most fundamental tasks in computer science. A majority of existing sorting algorithms are so-called "comparison-based sorting", whose basic operation is a comparison of two input elements.Its time-complexity is evaluated by the number of comparisons executed during the computation.Although researches on identifying the minimum number of comparisons have been performed more than 50 years, the optimal number of comparisons even for sorting 16 elements is still open.In this talk, I will give a brief survey on the research on this line.I will also describe algorithms which nearly match a theoretical lower bound asymptotically.

  2021.05.24 Mon. 10:00-12:00

  10th CoRe Seminar
  Speaker :TERUYAMA, Junichi (U. Hyogo, Group B01) Title :Sorting algorithms with small number of comparisons Sumarry :
• Zero-suppressed binary decision diagram (ZDD) is a compressed data structure for representing a family set. Algorithms that enumerate subgraphs such as paths and spanning trees of a given graph and construct ZDDs representing them are known. Moreover, algorithms that construct ZDDs for chordal subgraphs, interval subgraphs, planar subgraphs, and so on, have been proposed. We can apply constructed ZDDs to various applications including hotspot detection, electral districting and pencil puzzle solvers. In this talk, features of ZDDs and recent research on enumeration of subgraphs using ZDDs are introduced.

  2021.02.19 Fri. 15:00-17:00

  7th CoRe Seminar
  Speaker :KAWAHARA, Jun (Kyoto U., Group B01) Title :Subgraph enumeration using ZDDs Sumarry :
• We exlain the three research topics: bounded model checking, SAT planning, and network update. Although computational problems considered in these topics (and also applications) are different, they are, in essence, required to compute some form of the reachability of states, and hence have a close relation with the emerging discipline of combinatorial reconfiguration. This talk aims to provide basic knowledge of these topics to make it possible to discuss how they are related to the combinatorial reconfiguration.

  2021.01.22 Fri. 15:00-17:00

  5th CoRe Seminar
  Speaker :TODA, Takahisa (U. Electro-Communications, Group B01） Title :Bounded Model Checking, SAT Planning, and Network Update Sumarry :