Tsuyoshi Hashimoto

Bio: Tsuyoshi Hashimoto is an academic researcher. The author has contributed to research in topics: Vulnerability (computing) & Robustness (computer science). The author has an hindex of 2, co-authored 2 publications receiving 1392 citations.

Reliability, resiliency, and vulnerability criteria for water resource system performance evaluation

Abstract: Three criteria for evaluating the possible performance of water resource systems are discussed. These measures describe how likely a system is to fail (reliability), how quickly it recovers from failure (resiliency), and how severe the consequences of failure may be (vulnerability). These criteria can be used to assist in the evaluation and selection of alternative design and operating policies for a wide variety of water resource projects. The performance of a water supply reservoir with a variety of operating policies illustrates their use.

Robustness of water resources systems

Abstract: When water resource systems investments are made there is little assurance that the predicted performance will coincide with the actual performance. Robustness is proposed as a measure of the likelihood that the actual cost of a proposed project will not exceed some fraction of the minimum possible cost of a system designed for the actual conditions that occur in the future. The robustness criterion is illustrated by its application to the planning of water supply systems in southwestern Sweden.

Optimal Operation of Multireservoir Systems: State-of-the-Art Review

Abstract: With construction of new large-scale water storage projects on the wane in the U.S. and other developed countries, attention must focus on improving the operational effectiveness and efficiency of existing reservoir systems for maximizing the beneficial uses of these projects. Optimal coordination of the many facets of reservoir systems requires the assistance of computer modeling tools to provide information for rational management and operational decisions. The purpose of this review is to assess the state-of-the-art in optimization of reservoir system management and operations and consider future directions for additional research and application. Optimization methods designed to prevail over the high-dimensional, dynamic, nonlinear, and stochastic characteristics of reservoir systems are scrutinized, as well as extensions into multiobjective optimization. Application of heuristic programming methods using evolutionary and genetic algorithms are described, along with application of neural networks and fuzzy rule-based systems for inferring reservoir system operating rules.

Reliability, resiliency, and vulnerability criteria for water resource system performance evaluation

Abstract: Three criteria for evaluating the possible performance of water resource systems are discussed. These measures describe how likely a system is to fail (reliability), how quickly it recovers from failure (resiliency), and how severe the consequences of failure may be (vulnerability). These criteria can be used to assist in the evaluation and selection of alternative design and operating policies for a wide variety of water resource projects. The performance of a water supply reservoir with a variety of operating policies illustrates their use.

Agility from First Principles: Reconstructing the Concept of Agility in Information Systems Development

Abstract: Awareness and use of agile methods has grown rapidly among the information systems development (ISD) community in recent years. Like most previous methods, the development and promotion of these methods have been almost entirely driven by practitioners and consultants, with little participation from the research community during the early stages of evolution. While these methods are now the focus of more and more research efforts, most studies are still based on XP, Scrum, and other industry-driven foundations, with little or no conceptual studies of ISD agility in existence. As a result, this study proposes that there are a number of significant conceptual shortcomings with agile methods and the associated literature in its current state, including a lack of clarity, theoretical glue, parsimony, limited applicability, and naivety regarding the evolution of the concept of agility in fields outside systems development. Furthermore, this has significant implications for practitioners, rendering agile method comparison and many other activities very difficult, especially in instances such as distributed development and large teams that are not conducive to many of the commercial agile methods. This study develops a definition and formative taxonomy of agility in an ISD context, based on a structured literature review of agility across a number of disciplines, including manufacturing and management where the concept originated, matured, and has been applied and tested thoroughly over time. The application of the texonomy in practice is then demonstrated through a series of thought trials conducted in a large multinational organization. The intention is that the definition and taxonomy can then be used as a starting point to study ISD method agility regardless of whether the method is XP or Scrum, agile or traditional, complete or fragmented, out-of-the-box or in-house, used as is or tailored to suit the project context.