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Stationary Reuse of Electric Vehicle Batteries and Their Utilization in Regional Microgrid
No full text近年，地球温暖化防止とエネルギー自給率向上，災害対応のため，地域分散型の再生可能エネルギー(RE)の導入拡大が求められている。固定価格買い取り制度(FIT)により，地域へ RE の太陽光発電、風力発電及びバイオガス発電等の普及が進んでいる。上記の社会的背景に対して、地域側からは、頻度が少ない災害のための設備投資をなるべく少なくして非常時のレジリエンスを確保したい、また現状は FIT で活用できている RE を、制度終了後も維持したいというニーズが顕在化している。上記に対応する有効なシステムとして、域内で電力需給調整を行う地域マイクログリッド(MG)があり、平常時に分散型 RE を活用し、非常時にはレジリエンスを確保するポテンシャルを有する。先行研究により、地域 MG のモデル検討や実証が進められており、課題も明確化されつつある。主要な課題は、設備投資及びランニングコストに関する以下の２項目である。１つ目は、RE施設と需要エリアの街区が隣接しておらず、エネルギー輸送が高コストであること、２つ目は、需給調整を行う蓄電システムが高コストなことである。前者に対しては、エネルギー輸送を低コストにできる MG モデルの提案、評価及び実証が期待されている。後者に対しては、2025 年に世界中の EV 等の電動自動車で使用済みの駆動用蓄電池は 90 GWh を超え，その約 1/3 が再利用される予測となっており，EV 等で使用済みの蓄電池をリユースすることによる低コスト化が期待されている。ところで、EV 等で使用済みの蓄電池を定置リユースするためには、性能ばらつきに対応する特有の活用技術が必要となる。具体的には、1 次利用後の性能ばらつきを安価かつ高精度に選別する技術、及び定置リユース運用中に蓄電池の健全度を診断する技術などがある。本研究では、EV 等で使用済みの蓄電池を定置リユースするための特有の活用技術を提案することを目的として、1 次利用後の性能ばらつきを安価かつ高精度に選別する技術、及び定置リユース運用中に蓄電池の健全度を診断する技術を提案する。また、地域 MG でエネルギー輸送を低コスト化することを目的に、EV 及び定置リユース蓄電池を活用した MG モデルの提案及び蓄電池と EV の協調制御方式を開発し評価する。In recent years, distributed renewable energy (RE) has been required in Japan to prevent global warming, improve the degree of self-sufficiency in energy and resiliency against disasters. The concept of a regional microgrid (MG) is to evolve a part of the existing distribution system into a microgrid, together with regional RE resources available close to the demand area. One of the difficulties of regional MG is its expensive capital cost, especially paid for larger facility capacities required for rare emergency situations such as disasters. The regional MG has the potential to promote the RE, because the MG regulates power balance between supply and demand using batteries. Although expensive new battery systems have prevented practical use, inexpensive reused batteries, which have completed their primary use, might resolve the issue. The reused batteries from electric vehicles (EVs) exceed 90 GWh around the world and about one-third of EV batteries are projected to be repurposed by 2025. In addition, the percentage of the EVs to all vehicles is expected to advance to 35.7% by 2030. Therefore, it is possible that with a certain level of penetration of the EVs, there will be enough capacity to store energy for efficient operation of the MG.
By the way, in order to reuse EV batteries in stationary applications, which have completed their primary use, specific technology is required to regulate performance variations. Specifically, there are technologies to screen performance variations after primary use and to diagnose the state of health of reused batteries during system operation.
This paper proposes that screening and diagnosis of the state of health is a key technology for RE development using reused batteries which have performance variation. The proposed screening method, which includes multilayer AI analysis and MT system based on the Taguchi method, determines whether the capacity, as the measure of battery performance, exceeds the threshold. The proposed diagnostic method, based on current sharing ratio in parallel, determines whether the capacity, as the measure of battery performance, is higher than other stacks. This paper also proposes a coordinated control scheme for EVs and reused batteries for supply and demand balancing during an emergency and demonstrates how the proposed control scheme realizes the virtual distribution line function by EV
Model Reduction and Control of Boolean Networks Using Binary Decision Diagrams
No full textA BN is well known as a discrete model for analysis and control of complex networks such as gene regulatory networks. In the last decade, there has been much attention on analysis and control of BNs. There, the semi-tensor product (STP) method is widely used for calculations on BN. However, STP has a weakness in that it cannot represent large BNs. Since complex networks are large-scale in general, it is important to consider the model reduction. In this thesis, a model reduction method and control method of BNs using a BDD (binary decision diagram) is proposed. A BDD is a data structure used to represent Boolean functions. Logical operations of Boolean functions using a BDD are more efficient than using the STP method. The organization of this thesis is as follows. In Chapter 1, we illustrate this study’s background and the motivation. In Chapter 2, we explain BNs, BDDs, and the existing BN reduction method in preparation for the main topics in Chapters 2 to 4. We explain interaction graphs, transition graphs, and fixed points as important elements of BNs. In explaining the existing BN reduction method, we provide examples of calculations using semi-tensors and show that this method cannot be applied to large-scale BNs. In Chapter 3, we consider implementing the existing reduction method using BDDs. Since the calculations of the existing method cannot be simply replicated using BDDs, it is necessary to redevelop the procedures that assume the use of BDDs. In order to use BDDs efficiently, we consider utilizing the interaction graph expressing interactions between elements of the state. We show that this method is effective in large-scale BNs where STP method is not applicable. The reduction method in Chapter 3 does not pursue minimality. In Chapter 4, we consider a reduction method to further reduce the reduced model obtained in Chapter 3. We construct a reduction policy that is different from the existing reduction method that is used as the basis in Chapter 3. Like the method in Chapter 3, this method makes it possible to perform calculations using BDDs by utilizing interaction graphs. We show that this method is effective for BNs that cannot be further reduced by the method in Chapter 3. In Chapter 5, we consider the finite-time control problem of BNs. The finite-time control problem is to find all sequences of initial states and control input sequences that can reach the target state at a given final time. This problem has been proven to be NP-hard. In this chapter, we present a method for solving finite-time control problems using BDDs. Although BDDs have worse computational complexity in the worst case, they provide efficient solutions in many cases. In addition, we consider the problem of applying some control specifications to a typical finite-time control problem. We show an example of calculation to find all solutions for a large-scale BN, and an example to extract solutions that satisfy the control specification from those solutions. In Chapter 6, this thesis is concluded with a summary of the obtained results and some perspectives on the open problems
Preliminary Archaeological Field Report at Hamanaka 2 Site, Rebun Island, Hokkaido, JAPAN
No full textClinical and Basic Pathophysiological Approaches to the Challenges in Diagnosis and Treatment of Osteoporosis [an abstract of entire text]
No full text配架番号：2888この博士論文全文の閲覧方法については、以下のサイトをご参照ください。https://www.lib.hokudai.ac.jp/dissertations/copy-guides
Genome-wide CRISPR screen identifies MAD2L1BP and ANAPC15 as targets for brentuximab vedotin sensitivity in CD30+ PTCL [an abstract of dissertation and a summary of dissertation review]
No full text配架番号：291
マクロから分子レベルまでのトランススケール直接観察によるDNゲルの降伏過程に関する研究 [全文の要約]
No full textこの博士論文全文の閲覧方法については、以下のサイトをご参照ください。https://www.lib.hokudai.ac.jp/dissertations/copy-guides
How Operational Strategies for Children's Cafeterias are Defined : From the Perspective of the Interaction Between the Organisation and the Environment
No full text近年，地域の子どもを主な対象とする低額または無料の「子ども食堂」が，日本全国で急速に拡大している。本研究は，子ども食堂の運営戦略がどのように定められるのかを，組織と環境の相互作用の観点から考察することを目的とする。研究方法として，子ども食堂の運営代表者へのインタビュー調査を実施し，「資源依存理論」と「新制度理論」に基づいて分析を行った。その結果，一見「自主的」に見える運営戦略も，実際には特定のメカニズムを介して外部環境の影響を受けていることが明らかとなった。子ども食堂の運営者は，運営戦略を決定する際に，環境に受動的に適応するだけでなく，能動的に環境を制御することもある。また，子ども食堂特有の特徴として，「個々の子ども食堂の実践と『子ども食堂』という概念との間に存在する張力」や，「『貧困』をめぐる社会意識と慈善資源のミスマッチ」といった課題が浮かび上がった。これらの知見を踏まえ，本研究は民間福祉活動の研究に対し，今後の方向性を示唆する。In recent years, low-cost or free “children's cafeterias” that mainly target local children have been rapidly expanding throughout Japan. The purpose of this study is to examine how the operational strategies of children's cafeterias are defined from the perspective of the interaction between the organization and the environment. As a research method, an interview survey was conducted with representatives of children's cafeteria operations, and analysis was conducted based on the “Resource Dependency Theory” and the “New Institution Theory. The results revealed that operational strategies that appear to be “voluntary” are in fact influenced by the external environment through specific mechanisms.
In determining their operational strategies, operators of children's cafeterias not only passively adapt to their environment, but also actively control it. In addition, issues such as “the tension that exists between individual children's cafeteria practices and the concept of ‘children's cafeteria’” and “the mismatch between social awareness and charitable resources regarding ‘poverty’” emerged as characteristics unique to children's cafeterias.
Based on these findings, this study suggests future directions for research on private welfare activities
