19,347 research outputs found

    Utility Disturbance Management in the Process Industry

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    Use of utilities, such as steam and cooling water, is very common at industrial sites. Utilities are often shared between several production areas, and a disturbance in the supply of a utility is therefore likely to affect a large part of the production site, and cause great loss of revenue. In order to minimize the loss of revenue due to disturbances in utilities, the optimal supply of utilities to different areas has to be determined. It is not evident how utility resources should be divided, as both buffer tank levels, the connections between areas and profitability of different areas must be considered. This thesis presents a general method for reducing the loss of revenue due to disturbances in utilities, the Utility Disturbance Management method (UDM). The method concerns identifying disturbances in utilities, estimating the loss of revenue due to such disturbances, and finding strategies for reducing the loss. A model of the production site is needed to complete all steps of the method. In this thesis, some modeling approaches are suggested, and on/off production modeling with and without buffer tanks is described in detail. The UDM method is applied to an industrial site at Perstorp using these two modeling approaches

    An Overview of Economic Approaches to Information Security Management

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    The increasing concerns of clients, particularly in online commerce, plus the impact of legislations on information security have compelled companies to put more resources in information security. As a result, senior managers in many organizations are now expressing a much greater interest in information security. However, the largest body of research related to preventing breaches is technical, focusing on such issues as encryption and access control. In contrast, research related to the economic aspects of information security is small but rapidly growing. The goal of this technical note is twofold: i) to provide the reader with an structured overview of the economic approaches to information security and ii) to identify potential research directions

    Hierarchical Scheduling and Utility Disturbance Management in the Process Industry

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    This thesis deals with control of production at large-scale process industrial sites in the presence of disturbances. The main focus is on disturbances in the supply of utilities such as steam, cooling water and electricity. A general method for reducing the revenue loss due to disturbances in utilities is introduced, which may provide both proactive and reactive disturbance management strategies. Utility availability and area availability are introduced as performance indicators. These measures are used to obtain quick estimations of the revenue losses related to each utility. To obtain reactive strategies for utility disturbance management, a simple model of how utilities affect production in an area, and how utilities are shared between areas, is introduced. The modeling approach is utilized to formulate the production control problem at disturbances in utilities as an optimization problem. Measurement data are used to obtain empirical models of utility disturbances at an industrial site, which may be used as input to the optimization. Since production control closely relates to production scheduling, the integration of production scheduling based on orders and forecasts with production control at disturbances in utilities is studied in the final part of the thesis

    Industry structure and regulation

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    As private firms become increasingly involved in the development of key infrastructure, redefining the role of government from that of serviceprovider to regulator presents both challenges and opportunities. The factors that give rise to sector reforms color how much policymakers invest in regulatory design during the reform process. Nevertheless, two factors are essential to sustainable sector and regulatory reform. First, the right structure must be established for the industry concerned, a structure that allows competition appropriate for that industry. Second, the objectives of regulation must be well defined, with a clear distinction between policymaking, policy implementation, and operations. The extent to which competition can be harnessed to help make regulation efficient, effective, and sustainable depends on the intrinsic technical characteristics of the sector. Each decision affects the sustainability of the regulatory regime in the face of the threat of regulatory capture (both political and commercial). Careful regulatory design is crucial not only for successful sectoral reform but also to balance the interests of various actors (government, consumers, developers, investors, and financiers). One model that has been relatively successful combines new entry, unbundled services, and the unambiguous spelling out of the legal rights and duties for both public and private service providers, administered by an autonomous regulatory authority. Problems with regulation often result as much from inadequate attention to sector structure and fostering competition as from weaknesses in the regulatory authority's institutional capacity. As for the tools of regulation, despite differences in some details between licenses and concessions (and their many contractual variations), these are basically instruments that establish the rights and obligations of contracting parties. Choices about where these rights and obligations are located in the legal hierarchy are shaped by a country's institutional capacity and legal traditions. But the existence of instruments to establish those rights and obligations does not eliminate the need for institutionsto administer them, and thus carry out the regulatory function. Establishing effective sectorwide regulation can be difficult in a developing country, but it is necessary. Policymakers will be able to create effective regulatory regimes where adequate attention is given to sector structure, competition, and institution-building.Environmental Economics&Policies,Trade Finance and Investment,Knowledge Economy,ICT Policy and Strategies,Decentralization,Environmental Economics&Policies,Administrative&Regulatory Law,ICT Policy and Strategies,Water and Industry,Knowledge Economy

    Analyzing the Concept of Planetary Boundaries from a Strategic Sustainability Perspective: How Does Humanity Avoid Tipping the Planet?

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    abstract: Recently, an approach for global sustainability, the planetary-boundary approach (PBA), has been proposed, which combines the concept of tipping points with global-scale sustainability indicators. The PBA could represent a significant step forward in monitoring and managing known and suspected global sustainability criteria. However, as the authors of the PBA describe, the approach faces numerous and fundamental challenges that must be addressed, including successful identification of key global sustainability metrics and their tipping points, as well as the coordination of systemic individual and institutional actions that are required to address the sustainability challenges highlighted. We apply a previously published framework for systematic and strategic development toward a robust basic definition of sustainability, i.e., the framework for strategic sustainable development (FSSD), to improve and inform the PBA. The FSSD includes basic principles for sustainability, and logical guidelines for how to approach their fulfillment. It is aimed at preventing unsustainable behavior at both the micro, e.g., individual firm, and macro, i.e., global, levels, even when specific global sustainability symptoms and metrics are not yet well understood or even known. Whereas the PBA seeks to estimate how far the biosphere can be driven away from a “normal” or “natural” state before tipping points are reached, because of ongoing violations of basic sustainability principles, the FSSD allows for individual planners to move systematically toward sustainability before all impacts from not doing so, or their respective tipping points, are known. Critical weaknesses in the PBA can, thus, be overcome by a combined approach, significantly increasing both the applicability and efficacy of the PBA, as well as informing strategies developed in line with the FSSD, e.g., by providing a “global warning system” to help prioritize strategic actions highlighted by the FSSD. Thus, although ongoing monitoring of known and suspected global sustainability metrics and their possible tipping points is a critical part of the evolving sustainability landscape, effective and timely utilization of planetary-boundary information on multiple scales requires coupling to a strategic approach that makes the underlying sustainability principles explicit and includes strategic guidelines to approach them. Outside of such a rigorous and systems-based context, the PBA, even given its global scale, risks leading individual organizations or planners to (i) focus on “shares” of, e.g., pollution within the PBs and negotiations to get as high proportion of such as possible, and/or (ii) awaiting data on PBs when such do not yet exist before they act, and/or (iii) find it difficult to manage uncertainties of the data once such have arrived. If global sustainability problems are to be solved, it is important that each actor recognizes the benefits, not the least self-benefits, of designing and executing strategies toward a principled and scientifically robust definition of sustainability. This claim is not only based on theoretical reasoning. A growing number of sectors, businesses, and municipalities/cities around the world are already doing it, i.e., not estimating “allowed” shares of, say fossil CO[subscript 2] emissions, but gradually moving away from unsustainable use of fossil fuels and other unsustainable practices altogether.The final version of this article, as published in Ecology and Society, can be viewed online at: https://www.ecologyandsociety.org/vol18/iss2/art5

    Gauging the Vulnerability of Local Water Utilities to Extreme Weather Events

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    Water utilities that rely on surface water may be vulnerable to future droughts and floods, a vulnerability that may be magnified by climate perturbations as well as shorter-term and, in some cases, ongoing changes in the political and regulatory environment in which utilities operate.. Unfortunately, day-to-day responsibilities currently occupy most utility operators, leaving little time to plan for inherently uncertain effects. The record of actual responses to past droughts and floods can be illuminating, however, particularly when placed in the context of plausible hydrologic and institutional disruptions. This paper draws on interviews of water utility operators in the northwestern U.S. to highlight opportunities and constraints that water utilities may face vis-à-vis such disruptions. Key considerations affecting vulnerabilities include water rights, institutional barriers to efficient utility operations, hazards management policy, and the fiscal status of utilities.Key Words: water utilities, extreme events, environmental planning, climate variability, climate change, adaptation

    Datacenter Traffic Control: Understanding Techniques and Trade-offs

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    Datacenters provide cost-effective and flexible access to scalable compute and storage resources necessary for today's cloud computing needs. A typical datacenter is made up of thousands of servers connected with a large network and usually managed by one operator. To provide quality access to the variety of applications and services hosted on datacenters and maximize performance, it deems necessary to use datacenter networks effectively and efficiently. Datacenter traffic is often a mix of several classes with different priorities and requirements. This includes user-generated interactive traffic, traffic with deadlines, and long-running traffic. To this end, custom transport protocols and traffic management techniques have been developed to improve datacenter network performance. In this tutorial paper, we review the general architecture of datacenter networks, various topologies proposed for them, their traffic properties, general traffic control challenges in datacenters and general traffic control objectives. The purpose of this paper is to bring out the important characteristics of traffic control in datacenters and not to survey all existing solutions (as it is virtually impossible due to massive body of existing research). We hope to provide readers with a wide range of options and factors while considering a variety of traffic control mechanisms. We discuss various characteristics of datacenter traffic control including management schemes, transmission control, traffic shaping, prioritization, load balancing, multipathing, and traffic scheduling. Next, we point to several open challenges as well as new and interesting networking paradigms. At the end of this paper, we briefly review inter-datacenter networks that connect geographically dispersed datacenters which have been receiving increasing attention recently and pose interesting and novel research problems.Comment: Accepted for Publication in IEEE Communications Surveys and Tutorial
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