15,389 research outputs found

    A Dynamic Risk Optimization Model for Evaluating Profitable and Feasible Water Management Plans

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    Currently the South African government is advocating the cultivation of high valued crops and more efficient use of available water resources through the adoption o f more efficient irrigation technology and irrigation scheduling. A requirement of the National Water Act (Act 36 of 1998) is the compilation of water management plans. The main objective of this paper is to develop a multiperiod mathematical risk programming model able of assisting water user associations with the compilation of water management plans that are both profitable and feasible. Special care was taken to represent canal capacities and irrigation system application rates in the model. Risk simulation procedures are used to generate an appropriately correlated inter- and intra-temporal risk matrix for the programming model. A combination of subjectively elicited distributions of crop yield and objective data on crop prices were used to characterize risk. The model was applied to a representative flood irrigation farm in the Vaalharts irrigation scheme South Africa to demonstrate the capability of the model to optimize water use over a 15 year planning horizon. Model results clearly indicated the potential of high value crops and more efficient irrigation technology to soften the impact of water shortages. Furthermore infrastructure, the financial position of the farmer and the level of risk averseness have significantly impacted on the results. Policy makers and government authorities should take cognizance of these factors when evaluating water use efficiency and water management plans of different water user associations. Improvements in the adopted modeling procedure are also made.Dynamic Linear Programming, risk, irrigation, feasibility, South Africa, Resource /Energy Economics and Policy, C6, Q15, Q12,

    Mission Investments At The Packard Foundation

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    Since the Packard Foundation's first PRI in 1980, its approach to mission investing has evolved dramatically. This report by Redstone Strategy Group documents key learnings from some of the Foundation's more innovative, complex deals -- experiences that pushed the Foundation beyond the land and facilities PRIs that typified its early mission investments.It closes with some of the most challenging questions that remain for the Foundation and the field as the value and limitations of mission investing come into sharper focus

    Understanding smart contracts as a new option in transaction cost economics

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    Among different concepts associated with the term blockchain, smart contracts have been a prominent one, especially popularized by the Ethereum platform. In this study, we unpack this concept within the framework of Transaction Cost Economics (TCE). This institutional economics theory emphasizes the role of distinctive (private and public) contract law regimes in shaping firm boundaries. We propose that widespread adoption of the smart contract concept creates a new option in public contracting, which may give rise to a smart-contract-augmented contract law regime. We discuss tradeoffs involved in the attractiveness of the smart contract concept for firms and the resulting potential for change in firm boundaries. Based on our new conceptualization, we discuss potential roles the three branches of government – judicial, executive, and legislative – in enabling and using this new contract law regime. We conclude the paper by pointing out limitations of the TCE perspective and suggesting future research directions

    Review of integrated approaches to river basin, planning, development and management

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    Piecemeal approaches to river basin development and management may not fully recognize the interactions and interdependence among components of a river basin system. River basin management that focuses on a single water use, on a single sector, or on the supply to particular segment of the basin population may inadvertently disrupt other sectors of the economy (in time or space). Hence, advocating for a systems approach to river basin development - for models that could help account for a river basin's key components and help address various objectives. The authors review the literature on such economic models, including models that deal with issues of water quality and quantity or with environmental considerations, recreational demand, countrywide planning, and multiple objective planning. Their review may serve as a source of references for those who need to consider whether they can use a model. Readers can evaluate the suitability, advantages, and disadvantages of particular modeling approaches for specific objectives.Water Conservation,River Basin Management,Water and Industry,Environmental Economics&Policies,Decentralization,Environmental Economics&Policies,Water Conservation,Water Supply and Sanitation Governance and Institutions,Water and Industry,Town Water Supply and Sanitation

    Selecting projects in a portfolio using risk and ranking

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    There are three dimensions in project management: time, cost and performance. Risk is a characteristic related to the previous dimensions and their relationships. A risk equation is proposed based on the nature of the uncertainty associated to each dimension as well as the relationship between the uncertainties. A ranking equation that is able to prioritise projects is proposed and discussed. The problem solved here is which projects to select in a given portfolio of projects. The model is implemented in a group decision support system (GDSS) which can guide decisionmakers in their decision process. However, the system is not intended as a substitution of the decisionmaker task, but merely as an aid. The methodology used is analysis of the equations proposed and trial and error based on examples. This paper’s main contribution is the risk equation and the ranking equation

    A REVIEW OF APPLICATIONS OF MULTIPLE - CRITERIA DECISION-MAKING TECHNIQUES TO FISHERIES

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    Management of public resources, such as fisheries, is a complex task. Society, in general, has a number of goals that it hopes to achieve from the use of public resources. These include conservation, economic, and social objectives. However, these objectives often conflict, due to the varying opinions of the many stakeholders. It would appear that the techniques available in the field of multiple-criteria decision-making (MCDM) are well suited to the analysis and determination of fisheries management regimes. However, to date, relatively few publications exist using such MCDM methods compared to other applicational fields, such as forestry, agriculture, and finance. This paper reviews MCDM applied to fishery management by providing an overview of the research published to date. Conclusions are drawn regarding the success and applicability of these techniques to analyzing fisheries management problems.Resource /Energy Economics and Policy,

    Elevating commodity storage with the SALSA host translation layer

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    To satisfy increasing storage demands in both capacity and performance, industry has turned to multiple storage technologies, including Flash SSDs and SMR disks. These devices employ a translation layer that conceals the idiosyncrasies of their mediums and enables random access. Device translation layers are, however, inherently constrained: resources on the drive are scarce, they cannot be adapted to application requirements, and lack visibility across multiple devices. As a result, performance and durability of many storage devices is severely degraded. In this paper, we present SALSA: a translation layer that executes on the host and allows unmodified applications to better utilize commodity storage. SALSA supports a wide range of single- and multi-device optimizations and, because is implemented in software, can adapt to specific workloads. We describe SALSA's design, and demonstrate its significant benefits using microbenchmarks and case studies based on three applications: MySQL, the Swift object store, and a video server.Comment: Presented at 2018 IEEE 26th International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS
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