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Mexican fresh tomato exports in the North American market: A case study of the effects of productivity on competitiveness

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CANADIAN JOURNAL OF PLANT SCIENCE 2013年第5期93卷 839-850页

作者： Borja-Bravo, Mercedes Garcia-Salazar, Jose Alberto Skaggs, Rhonda K. Agr Pecuarias INIFAP Aguascalientes Inst Nacl Invest Forest Pabellon De Arteaga Aguascalientes Mexico Colegio Postgrad Montecillo 56230 Estado De Mexic Mexico New Mexico State Univ MSC 3169 Las Cruces NM 88003 USA

The North American market for fresh tomatoes (Lycopersicon escolentum Mill.) involves a complicated web of bilateral trading relationships between the United States, Mexico and Canada. Trade in fresh tomatoes between the three countries has changed significantly in recent years. In particular, Mexico's share of total US fresh tomato imports from all countries decreased from 93 to 88%, while Canada's share of US fresh tomato imports increased from 3 to 11% between 1996 and 2009. Mexico's declining competitive position in the US fresh tomato market is also evidenced by the fact that the Mexican share of combined Mexico-Canada exports to the United States decreased from 97% to 89% between 1996 and 2009. A spatial and inter-temporal model was used to analyze the impact of increased Mexican tomato yields on the North American fresh tomato market. Results indicate that for the average year between 2005 and 2008, 20% higher yields would have resulted in a 15.1% increase in Mexico's tomato production and a 28.9% increase in fresh tomato exports from Mexico to the United States. As a result of higher Mexican tomato sector productivity, Canadian and US producers' shares of the US fresh tomato market would decrease and Mexico's would increase from 35.0 to 41.9%. The model shows that Mexico's share of US fresh tomato imports from both Mexico and Canada would grow from 88.1 to 90.3% as a result of the increased productivity. These results lead to the recommendation that increasing yields of this important export crop are key to maintaining and increasing the North American market competitiveness of Mexican-produced fresh tomatoes.

关键词： North American Free Trade Agreement economic integration trade tomatoes vegetables programming models agricultural productivity agriculture

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TOWARDS COMPUTING AS A UTILITY VIA ADAPTIVE MIDDLEWARE: AN EXPERIMENT IN CROSS-PARADIGM EXECUTION

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PARALLEL PROCESSING LETTERS 2013年第2期23卷

作者： Slawinski, Jaroslaw Sunderam, Vaidy Emory Univ Math & Comp Sci 400 Dowman DrW401 Atlanta GA 30322 USA

Rapid advances in cloud computing have made the vision of utility computing a near reality, but only in certain domains. For science and engineering parallel or distributed applications, on-demand access to resources within grids and clouds is hampered by two major factors: communication performance and paradigm mismatch issues. We propose a framework for addressing the latter aspect via software adaptations that attempt to reconcile model and interface differences between application needs and resource platforms. Such matching can greatly enhance flexibility in choice of execution platforms a key characteristic of utility computing even though they may not be a natural fit or may incur some performance loss. Our design philosophy, middleware components, and experiences from a cross-paradigm experiment are described.

关键词： Cloud computing computing as a utility middleware programming models paradigm interoperability

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Loop Level Speculation in a Task Based programming Model

Loop Level Speculation in a Task Based Programming Model

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20th International Conference on High Performance Computing (HiPC)

作者： Gayatri, Rahulkumar Badia, Rosa. M. Aygaude, Eduard Barcelona Supercomp Ctr Barcelona Spain CSIC Artificial Intelligence Res Inst IIIA Madrid Spain Univ Politecn Cataluna E-08028 Barcelona Spain

ISBN: (纸本)9781479907298

Uncountable loops (such as while loops in C) and if-conditions are some of the most common constructs in programming. While-loops are widely used to determine the convergence in linear algebra algorithms or goal finding problems from graph algorithms, to name a few. In general whileloops are used whenever the loop iteration space, the number of iterations a loop executes is unknown. Usually in while-loops, the execution of the next iteration is decided inside the current loop iteration (i.e. the execution of iteration i depends on the values computed in iteration i-1). This precludes their parallel execution in today's ubiquitous multi-core architectures. In this paper a technique to speculatively create parallel tasks from the next iterations before the current one completes is proposed. If consecutive loop-iterations are only control dependent, then multiple iterations can be executed simultaneously;later in the execution path, the runtime system will decide to either commit the results of such speculatively executed iterations or undo the changes made by them. Data dependences within or between non-speculative and speculative work are honored to guarantee correctness. The proposed technique is implemented in SMPSs, a task-based dataflow programming model for shared-memory multiprocessor architectures. The approach is evaluated on a set of applications from graph algorithms and linear algebra. Results are promising with an average increase in the speedup of 1.2x with 16 threads when compared to non speculative execution of the applications. The increase in the speedup is significant, since the performance gain is achieved over an already parallelized version of the benchmarks.

关键词： SMPSs Iteration space Speculation programming models

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Automated rapid prototyping of regular grid-based numerical applications using generalized elemental subroutines

Automated rapid prototyping of regular grid-based numerical ...

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IEEE 27th International Parallel and Distributed Processing Symposium (IPDPS)

作者： Situ, Yingchong Wang, Ye Li, Zhiyuan Purdue Univ Dept Comp Sci W Lafayette IN 47907 USA

ISBN: (纸本)9780769549712

Computational scientists and engineers commonly rely on established software libraries to achieve high performance and reliability in their numerical applications. Unfortunately, this approach does not work well if the desired functionality is absent in existing libraries or if the integration is difficult. In such scenarios, one is often forced to explore alternative algorithms and in-house implementations. Such exploration can be a challenging task for computational scientists and engineers without sufficient computer science background. To address this issue, we design and build an automated rapid prototyping tool for regular grid-based numerical applications. This new tool allows programmers to specify algorithms as composition of familiar computation patterns such as those easily found in open literature expressed as generalized elemental subroutines. The tool then automatically transforms such subroutines into code which adapts to the prescribed data structures and delivers performance expected from the underlying algorithms. We demonstrate the tool in use cases including a production-grade computational fluid dynamic application.

关键词： compiler analysis and optimization program transformation programming models

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programming ecological niche modeling workflows in the Cloud

Programming ecological niche modeling workflows in the Cloud

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IEEE 27th International Conference on Advanced Information Networking and Applications Workshops (WAINA)

作者： Lezzi, Daniele Rafanell, Roger Torres, Erik De Giovanni, Renato Blanquer, Ignacio Badia, Rosa M. Barcelona Supercomp Ctr Dept Comp Sci Barcelona Spain Artif Intelligence Res Inst CSIC Barcelona Spain Univ Politecn Valencia I3M CSIC CIEMAT Valencia Spain Centro Referencia Informat Ambient Campinas SP Brazil

ISBN: (纸本)9780769549521;9781467362399

In the last decades biology scientists have relied on their own resources and tools to run the experiments and store the results of the analysis. However, the explosion of big data and the growing availability of computational methods find an obstacle in the lack of computational and storage resources. Cloud computing platforms are emerging as potential solution to overcome these limitations, but adaptation of the applications to enable scientific users to benefit from resources acquired on demand is a complex process requiring multidisciplinary expertise. The EUBrazilOpenBio initiative is implementing an e-Infrastructure that provides biodiversity community with a rich set of computational and data resources exploiting existing cloud technologies from EU and Brazil. This paper presents the implementation of one of the two use cases selected, the environmental niche modeling by means of implementing such workflow through the COMPSs framework and its deployment on the EUBrazil OpenBio platform. The proposed approach has been evaluated on a Cloud testbed managed by the VENUS-C middleware.

关键词： Cloud niche modeling programming models workflows

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Modelling European Public Finance and Support for RDI Sector

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Procedia Economics and Finance 2013年 6卷 754-759页

作者： Mirela Nicolov Faculty of Economic Sciences University of OradeaRomania

In the present paper is introduced an econophysics model for the public finance and support in the European RDI sector, especially for EU15 respectively EU25.

关键词： Optimization Techniques programming models Dynamic Analysis Measurement of Economic Growth Public Economics Financial Economics Forecasting and Prediction Methods Simulation Methods Data Collection and Data Estimation Methodology Model Construction and Estimation Model Evaluation Validation and Selection Forecasting and Prediction Methods Econophysics.

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Parallel programming Patterns for Multi-Processor SoC: Application to Video Processing

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ACM TRANSACTIONS ON EMBEDDED COMPUTING SYSTEMS 2013年第1s期12卷 47-47页

作者： Paulin, Pierre G. Oezcan, Ali Erdem Gagne, Vincent Lavigueur, Bruno Benny, Olivier STMicroelect Canada Inc 16 Fitzgerald RdSuite 100 Ottawa ON K2H 8R6 Canada

Efficient, scalable and productive parallel programming is a major challenge for exploiting the future multiprocessor SoC platforms. This article presents the MultiFlex programming environment which has been developed to address this challenge. It is targeted for use on Platform 2012, a scalable multi-processor fabric. The MultiFlex environment supports high-level simulation, iterative platform mapping, and includes tools for programming model aware debug, trace, visualization and analysis. This article focuses on the two classes of programming abstractions supported in MultiFlex. The first is a set of Parallel programming Patterns (PPP) which offer a rich set of programming abstractions for implementing efficient data-and task-level parallel applications. The second is a Reactive Task Management (RTM) abstraction, which offers a lightweight C-based API to support dynamic dispatching of small grain tasks on tightly coupled parallel processing resources. The use of the MultiFlex native programming model is illustrated through the capture and mapping of two representative video applications. The first is a high-quality rescaling (HQR) application on a multiprocessor platform. We present the details of the optimization process which was required for mapping the HQR application, for which the reference code requires 350 GIPS (giga instructions per second), onto a 16 processor cluster. Our results show that the parallel implementation using the PPP model offers almost linear acceleration with respect to the number of processing elements. The second application is a high-definition VC-1 decoder. For this application, we illustrate two different parallel programming model variants, one using PPPs, the other based on RTM. These two versions are mapped onto two variants of a homogeneous version of the Platform 2012 multi-core fabric.

关键词： Performance Experimentation Languages programming models components multi-core platform mapping

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System-wide support for safety in pervasive spaces

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JOURNAL OF AMBIENT INTELLIGENCE AND HUMANIZED COMPUTING 2012年第2期3卷 113-123页

作者： Chen, Chao Helal, Sumi Univ Florida Dept Comp & Informat Sci & Engn Gainesville FL 32611 USA

This paper addresses issues of safety in pervasive spaces. We show how pervasive systems are different from traditional computer systems, and how their cyberphysical nature ties intimately with the users. Errors and conflicts in such space could have detrimental, dangerous or undesired effects on the user, the space, or the devices. There are no support systems or programming models conscious of the issue of safety. Unrestrained programming is the model de jour, which is inadequate. We need a programming model that encourages and obligates various roles engaged in the development of pervasive spaces to contribute to increasing safety. We propose a model that utilizes role-specific safety knowledge, and that takes advantage of the rich sensing and actuations capabilities of pervasive systems to detect and handle "conflicting contexts" and prevent or detect/avert "impermissible contexts". We present our model and discuss how it mitigates overall safety risks in presence of uncertainty due to multiple independent roles.

关键词： programming models for pervasive spaces Safety oriented programming model Support system Space safety Safety ontology programming models Roles

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OpenCL as a Unified programming Model for Heterogeneous CPU/GPU Clusters 12

OpenCL as a Unified Programming Model for Heterogeneous CPU/...

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17th ACM SIGPLAN Symposium on Principles and Practice of Parallel programming

作者： Kim, Jungwon Seo, Sangmin Lee, Jun Nah, Jeongho Jo, Gangwon Lee, Jaejin Seoul Natl Univ Sch Comp Sci & Engn Ctr Manycore Programming Seoul 151744 South Korea

ISBN: (纸本)9781450311601

In this paper, we propose an OpenCL framework for heterogeneous CPU/GPU clusters, and show that the framework achieves both high performance and ease of programming. The framework provides an illusion of a single system for the user. It allows the application to utilize multiple heterogeneous compute devices, such as multicore CPUs and GPUs, in a remote node as if they were in a local node. No communication API, such as the MPI library, is required in the application source. We implement the OpenCL framework and evaluate its performance on a heterogeneous CPU/GPU cluster that consists of one host node and nine compute nodes using eleven OpenCL benchmark applications.

关键词： Algorithm Design Experimentation Languages Measurement Performance OpenCL Clusters Heterogeneous computing programming models

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The Analysis of Impact of Energy Efficiency Requirements on programming Environments

The Analysis of Impact of Energy Efficiency Requirements on ...

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25th ACM/IEEE International Conference for High Performance Computing, Networking, Storage and Analysis (SC)

作者： Shalf, John Lawrence Berkeley Natl Lab NERSC CTO Berkeley CA 94720 USA

ISBN: (纸本)9780769549569;9781467362184

Our underlying machine model has presumed modest growth in parallelism, adherence to Amdahl ratios for speeds-and-feeds, weak-scaling for parallelism, uniform distance between processing elements within a node and between nodes in a system, and conservation of the all-important FLOP in our algorithm and software design. However, the new reality is that parallelism (particularly on-chip) is growing exponentially, bandwidth and memory capacity are increasingly scarce and force us towards strong-scaling, distance as measured by power and performance is increasingly non-uniform at all levels of the machine, and flops are now heavily discounted to the point that wasting any other resource to save a few flops is a losing proposition. The enormous mismatch between our ability to express concepts of locality and implicit parallelism in existing programming models subjects our codes to huge inefficiencies and reduced portability. Future programming models need to be designed to accommodate the first derivative of these emerging hardware trends (exponential parallelism growth, non-uniformity, SIMD width growth, and bandwidth conservation). The talk will discuss the evolution of this mismatch between hardware and abstract machine models, and discuss a path to develop hardware constructs that enable more efficient implementation of core programming model semantics (example PGAS-on-chip, fast global reduction networks). We can also explore software constructs that better reflect the real costs and layout of an algorithm onto the underlying machine architecture (example hierarchical data layout directives and programmable iteration spaces).

关键词： HPC data energy efficiency exascale manycore programming models

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