1,855 research outputs found

    Analysis of Energy Consumption Performance towards Optimal Radioplanning of Wireless Sensor Networks in Heterogeneous Indoor Environments

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    In this paper the impact of complex indoor environment in the deployment and energy consumption of a wireless sensor network infrastructure is analyzed. The variable nature of the radio channel is analyzed by means of deterministic in-house 3D ray launching simulation of an indoor scenario, in which wireless sensors, based on an in-house CyFi implementation, typically used for environmental monitoring, are located. Received signal power and current consumption measurement results of the in-house designed wireless motes have been obtained, stating that adequate consideration of the network topology and morphology lead to optimal performance and power consumption reduction. The use of radioplanning techniques therefore aid in the deployment of more energy efficient elements, optimizing the overall performance of the variety of deployed wireless systems within the indoor scenario

    Libra: An Economy driven Job Scheduling System for Clusters

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    Clusters of computers have emerged as mainstream parallel and distributed platforms for high-performance, high-throughput and high-availability computing. To enable effective resource management on clusters, numerous cluster managements systems and schedulers have been designed. However, their focus has essentially been on maximizing CPU performance, but not on improving the value of utility delivered to the user and quality of services. This paper presents a new computational economy driven scheduling system called Libra, which has been designed to support allocation of resources based on the users? quality of service (QoS) requirements. It is intended to work as an add-on to the existing queuing and resource management system. The first version has been implemented as a plugin scheduler to the PBS (Portable Batch System) system. The scheduler offers market-based economy driven service for managing batch jobs on clusters by scheduling CPU time according to user utility as determined by their budget and deadline rather than system performance considerations. The Libra scheduler ensures that both these constraints are met within an O(n) run-time. The Libra scheduler has been simulated using the GridSim toolkit to carry out a detailed performance analysis. Results show that the deadline and budget based proportional resource allocation strategy improves the utility of the system and user satisfaction as compared to system-centric scheduling strategies.Comment: 13 page

    Traceability -- A Literature Review

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    In light of recent food safety crises and international trade concerns associated with food or animal associated diseases, traceability has once again become important in the minds of public policymakers, business decision makers, consumers and special interest groups. This study reviews studies on traceability, government regulation and consumer behaviour, provide case studies of current traceability systems and a rough breakdown of various costs and benefits of traceability. This report aims to identify gaps that may currently exist in the literature on traceability in the domestic beef supply chain, as well as provide possible directions for future research into said issue. Three main conclusions can be drawn from this study. First, there is a lack of a common definition of traceability. Hence identifying similarities and differences across studies becomes difficult if not impossible. To this end, this study adopts CFIA’s definition of traceability. This definition has been adopted by numerous other agencies including the EU’s official definition of traceability however it may or may not be acceptable from the perspective of major Canadian beef and cattle trade partners. Second, the studies reviewed in this report address one or more of five key objectives; the impact of changing consumer behaviour on market participants, suppliers incentive to adopt or participate in traceability, impact of regulatory changes, supplier response to crisis and technical description of traceability systems. Drawing from the insights from the consumer studies, it seems as if consumers do not value traceability per se, traceability is a means for consumers to receive validation of another production or process attribute that they are interested in. Moreover, supply chain improvement, food safety control and accessing foreign market segments are strong incentives for primary producers and processors to participate in programs with traceability features. However the objectives addressed by the studies reviewed in this paper are not necessarily the objectives that are of most immediate relevance to decision makers about appropriate traceability standards to recommend, require, subsidize etc. In many cases the research objectives of previous work have been extremely narrow creating a body of literature that is incomplete in certain key areas. Third, case studies of existing traceability systems in Australia, the UK, Scotland, Brazil and Uruguay indicate that the pattern of development varies widely across sectors and regions. In summary, a traceability system by itself cannot provide value-added for all participants in the industry; it is merely a protocol for documenting and sharing information. Value is added to participants in the marketing chain through traceability in the form of reduced transactions costs in the case of a food safety incident and through the ability to shift liability. To ensure consumer benefit and have premiums returned to primary producers the type of information that consumers value is an important issue for future research. A successful program that peaks consumer interest and can enhance their eating experience can generate economic benefits to all sectors in the beef industry. International market access will increasingly require traceability in the marketing system in order to satisfy trade restrictions in the case of animal diseases and country of origin labelling, to name only a few examples. Designing appropriate traceability protocols industry wide is therefore becoming very important.traceability, institutions, Canada, consumer behaviour, producer behaviour, supply chain, Agricultural and Food Policy, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety, Health Economics and Policy, International Relations/Trade, Livestock Production/Industries, Marketing, Production Economics, D020, D100, D200, Q100,

    Cluster Computing in the Classroom: Topics, Guidelines, and Experiences

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    With the progress of research on cluster computing, more and more universities have begun to offer various courses covering cluster computing. A wide variety of content can be taught in these courses. Because of this, a difficulty that arises is the selection of appropriate course material. The selection is complicated by the fact that some content in cluster computing is also covered by other courses such as operating systems, networking, or computer architecture. In addition, the background of students enrolled in cluster computing courses varies. These aspects of cluster computing make the development of good course material difficult. Combining our experiences in teaching cluster computing in several universities in the USA and Australia and conducting tutorials at many international conferences all over the world, we present prospective topics in cluster computing along with a wide variety of information sources (books, software, and materials on the web) from which instructors can choose. The course material described includes system architecture, parallel programming, algorithms, and applications. Instructors are advised to choose selected units in each of the topical areas and develop their own syllabus to meet course objectives. For example, a full course can be taught on system architecture for core computer science students. Or, a course on parallel programming could contain a brief coverage of system architecture and then devote the majority of time to programming methods. Other combinations are also possible. We share our experiences in teaching cluster computing and the topics we have chosen depending on course objectives

    Farming out : a study.

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    Farming is one of severals ways of arranging for a group of individuals to perform work simultaneously. Farming is attractive. It is a simple concept, and yet it allocates work dynamically, balancing the load automatically. This gives rise to potentially great efficiency; yet the range of applications that can be farmed efficiently and which implementation strategies are the most effective has not been classified. This research has investigated the types of application, design and implementation that farm efficiently on computer systems constructed from a network of communicating parallel processors. This research shows that all applications can be farmed and identifies those concerns that dictate efficiency. For the first generation of transputer hardware, extensive experiments have been performed using Occam, independent of any specific application. This study identified the boundary conditions that dictate which design parameters farm efficiently. These boundary conditions are expressed in a general form that is directly amenable to other architectures. The specific quantitative results are of direct use to others who wish to implement farms on this architecture. Because of farming’s simplicity and potential for high efficiency, this work concludes that architects of parallel hardware should consider binding this paradigm into future systems so as to enable the dynamic allocation of processes to processors to take place automatically. As well as resulting in high levels of machine utilisation for all programs, this would also permanently remove the burden of allocation from the programmer

    Using a Full Spectral Raytracer for Calculating Light Microclimate in Functional-Structural Plant Modelling

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    Raytracers that allow the spatially explicit calculation of the fate of light beams in a 3D scene allow the consideration of shading, reflected and transmitted light in functional-structural plant models (FSPM). However, the spectrum of visible light also has an effect on cellular and growth processes. This recently created the interest to extend this modelling paradigm allowing the representation of detailed spectra instead of monochromatic or white light and to extend existing FSPM platforms accordingly. In this study a raytracer is presented which supports the full spectrum of light and which can be used to compute spectra from arbitrary light sources and their transformation at the organ level by absorption, reflection and transmission in a virtual canopy. The raytracer was implemented as an extension of the FSPM platform GroIMP

    Overview of the PALM model system 6.0

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    In this paper, we describe the PALM model system 6.0. PALM (formerly an abbreviation for Parallelized Large-eddy Simulation Model and now an independent name) is a Fortran-based code and has been applied for studying a variety of atmospheric and oceanic boundary layers for about 20 years. The model is optimized for use on massively parallel computer architectures. This is a follow-up paper to the PALM 4.0 model description in Maronga et al. (2015). During the last years, PALM has been significantly improved and now offers a variety of new components. In particular, much effort was made to enhance the model with components needed for applications in urban environments, like fully interactive land surface and radiation schemes, chemistry, and an indoor model. This paper serves as an overview paper of the PALM 6.0 model system and we describe its current model core. The individual components for urban applications, case studies, validation runs, and issues with suitable input data are presented and discussed in a series of companion papers in this special issue.Peer reviewe

    Overview of the PALM model system 6.0

    Get PDF
    In this paper, we describe the PALM model system 6.0. PALM (formerly an abbreviation for Parallelized Large-eddy Simulation Model and now an independent name) is a Fortran-based code and has been applied for studying a variety of atmospheric and oceanic boundary layers for about 20 years. The model is optimized for use on massively parallel computer architectures. This is a follow-up paper to the PALM 4.0 model description in Maronga et al. (2015). During the last years, PALM has been significantly improved and now offers a variety of new components. In particular, much effort was made to enhance the model with components needed for applications in urban environments, like fully interactive land surface and radiation schemes, chemistry, and an indoor model. This paper serves as an overview paper of the PALM 6.0 model system and we describe its current model core. The individual components for urban applications, case studies, validation runs, and issues with suitable input data are presented and discussed in a series of companion papers in this special issue

    Overview of the PALM model system 6.0

    Get PDF
    In this paper, we describe the PALM model system 6.0. PALM (formerly an abbreviation for Parallelized Largeeddy Simulation Model and now an independent name) is a Fortran-based code and has been applied for studying a variety of atmospheric and oceanic boundary layers for about 20 years. The model is optimized for use on massively parallel computer architectures. This is a follow-up paper to the PALM 4.0 model description in Maronga et al. (2015). During the last years, PALM has been significantly improved and now offers a variety of new components. In particular, much effort was made to enhance the model with components needed for applications in urban environments, like fully interactive land surface and radiation schemes, chemistry, and an indoor model. This paper serves as an overview paper of the PALM 6.0 model system and we describe its current model core. The individual components for urban applications, case studies, validation runs, and issues with suitable input data are presented and discussed in a series of companion papers in this special issue

    Using a Full Spectral Raytracer for Calculating Light Microclimate in Functional-Structural Plant Modelling

    Get PDF
    Raytracers that allow the spatially explicit calculation of the fate of light beams in a 3D scene allow the consideration of shading, reected and transmitted light in functional-structural plant models (FSPM). However, the spectrum of visible light also has an e ect on cellular and growth processes. This recently created the interest to extend this modelling paradigm allowing the representation of detailed spectra instead of monochromatic or white light and to extend existing FSPM platforms accordingly. In this study a raytracer is presented which supports the full spectrum of light and which can be used to compute spectra from arbitrary light sources and their transformation at the organ level by absorption,reection and transmission in a virtual canopy. The raytracer was implemented as an extension of the FSPM platform GroIMP
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