4,754 research outputs found

    A multi-agent based system to enable strategic and operational design coordination

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    This paper presents two systems which individually focus on different aspects of design coordination, namely strategic and operational. The systems were developed in parallel and individually contain related models that represent specific frames from a Design Coordination Framework developed by Andreasen et al. [1]. The focus of the strategic design management system is the management of design tasks, decisions, information, goals and rationale within the design process, whereas the focus of the operational design coordination system is the coordination of tasks and activities with respect to the near-optimal utilisation of available resources. A common interface exists which enables the two systems to be integrated and used as a single system with the aim of managing both strategicand operational design coordination. Hence, the objective of this work is to enable the design process to be conducted in a timely and appropriate manner

    Coordination approaches and systems - part II : an operational perspective

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    This is the second of two papers surveying research in coordination approaches and systems. This paper is concerned with operational coordination, which is aimed at coordinating activities such that the design process can be performed in a near optimal manner with respect to time, and the allocation and utilisation of resources. Aspects of coordination categorised as operational include resource management, scheduling and planning. The first of these two papers presents a review of coordination from a strategic perspective, which is concerned with the decision management aspects of coordination. Greater emphasis is now being placed on the significance of organising the design process as this affects time to market, product quality, cost, and consequently product success. The aim of this paper is to present a fundamental review of operational coordination approaches and systems. The 1990s has seen much progress being made towards a greater understanding and appreciation of coordination in various disciplines through the development of a wide range of approaches and systems. However, there remains a requirement to formally identify the key issues involved in coordination such that a widely accepted representation can be agreed upon. Consequently, research should continue to be supported in the exploration for a unified approach to coordination which will permit a broader and greater understanding of those aspects involved

    A system for co-ordinating concurrent engineering

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    Design of large made-to-order products invariably involves design activities which are increasingly being distributed globally in order to reduce costs, gain competitive advantage and utilise external expertise and resources. Designers specialise within their domain producing solutions to design problems using the tools and techniques with which they are familiar. They possess a relatively local perception of where their expertise and actions are consumed within the design process. This is further compounded when design activities are geographically distributed, resulting with the increased disassociation between an individual designer's activities and the overall design process. The tools and techniques used by designers rarely facilitate concurrency, producing solutions within a particular discipline without using or sharing information from other disciplines, and seldom considering stages within the product's life-cycle other than conceptual, embodiment or detail [1, 2]. Conventional management and maintenance of consistency throughout the product model can subsequently become difficult to achieve since there are many factors that need to be simultaneously considered whilst making achange to the product model

    Coordination approaches and systems - part I : a strategic perspective

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    This is the first part of a two-part paper presenting a fundamental review and summary of research of design coordination and cooperation technologies. The theme of this review is aimed at the research conducted within the decision management aspect of design coordination. The focus is therefore on the strategies involved in making decisions and how these strategies are used to satisfy design requirements. The paper reviews research within collaborative and coordinated design, project and workflow management, and, task and organization models. The research reviewed has attempted to identify fundamental coordination mechanisms from different domains, however it is concluded that domain independent mechanisms need to be augmented with domain specific mechanisms to facilitate coordination. Part II is a review of design coordination from an operational perspective

    Lagrangian Floer superpotentials and crepant resolutions for toric orbifolds

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    We investigate the relationship between the Lagrangian Floer superpotentials for a toric orbifold and its toric crepant resolutions. More specifically, we study an open string version of the crepant resolution conjecture (CRC) which states that the Lagrangian Floer superpotential of a Gorenstein toric orbifold X\mathcal{X} and that of its toric crepant resolution YY coincide after analytic continuation of quantum parameters and a change of variables. Relating this conjecture with the closed CRC, we find that the change of variable formula which appears in closed CRC can be explained by relations between open (orbifold) Gromov-Witten invariants. We also discover a geometric explanation (in terms of virtual counting of stable orbi-discs) for the specialization of quantum parameters to roots of unity which appears in Y. Ruan's original CRC ["The cohomology ring of crepant resolutions of orbifolds", Gromov-Witten theory of spin curves and orbifolds, 117-126, Contemp. Math., 403, Amer. Math. Soc., Providence, RI, 2006]. We prove the open CRC for the weighted projective spaces X=P(1,ā€¦,1,n)\mathcal{X}=\mathbb{P}(1,\ldots,1,n) using an equality between open and closed orbifold Gromov-Witten invariants. Along the way, we also prove an open mirror theorem for these toric orbifolds.Comment: 48 pages, 1 figure; v2: references added and updated, final version, to appear in CM

    Role of a gamma-aminobutryic acid (GABA) receptor mutation in the evolution and spread of Diabrotica virgifera virgifera resistance to cyclodiene insecticides

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    The western corn rootworm, Diabrotica virgifera virgifera, is a damaging pest of cultivated corn that was controlled by applications of cyclodiene insecticides from the late 1940s until resistance evolved āˆ¼10 years later. Range expansion from the western plains into eastern USA coincides with resistance development. An alanine to serine amino acid substitution within the Rdl subunit of the gamma-aminobutyric acid (GABA) receptor confers resistance to cyclodiene insecticides in many species. We found that the non-synonymous single nucleotide polymorphism (SNP) G/T at the GABA receptor cDNA position 838 (G/T838) of D.ā€‰v. virgifera resulted in the alanine to serine change, and the codominant SNP allele T838 was genetically linked to survival of beetles in aldrin bioassays. A phenotypic gradient of decreasing susceptibility from west to east was correlated with higher frequencies of the resistance-conferring T838 allele in the eastern-most populations. This pattern exists in opposition to perceived selective pressures since the more eastern and most resistant populations probably experienced reduced exposure. The reasons for the observed distribution are uncertain, but historical records of the range expansion combined with the distribution of susceptible and resistant phenotypes and genotypes provide an opportunity to better understand factors affecting the species\u27 range expansion

    Mirror Map as Generating Function of Intersection Numbers: Toric Manifolds with Two K\"ahler Forms

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    In this paper, we extend our geometrical derivation of expansion coefficients of mirror maps by localization computation to the case of toric manifolds with two K\"ahler forms. Especially, we take Hirzebruch surfaces F_{0}, F_{3} and Calabi-Yau hypersurface in weighted projective space P(1,1,2,2,2) as examples. We expect that our results can be easily generalized to arbitrary toric manifold.Comment: 45 pages, 2 figures, minor errors are corrected, English is refined. Section 1 and Section 2 are enlarged. Especially in Section 2, confusion between the notion of resolution and the notion of compactification is resolved. Computation under non-zero equivariant parameters are added in Section

    Metal composition of ambient PM2.5 influences severity of allergic airways disease in mice.

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    Children living in Hettstedt in eastern Germany have been reported to have a higher prevalence of sensitization to common aeroallergens than another cohort living in the neighboring city of Zerbst; these differences correlated with the presence of industrial air pollution. Samples of fine particulate matter (< 2.5 micro m aerodynamic diameter; PM(2.5)) collected in Hettstedt in 1999 had several-fold higher levels of zinc, magnesium, lead, copper, and cadmium than samples from Zerbst. To determine if the results from epidemiologic studies could be repeated in an animal model, we administered PM(2.5) from Hettstedt and Zerbst to ovalbumin-allergic mice. In Balb/c mice, PM(2.5) from Hettstedt, but not PM(2.5) from Zerbst or control filter extract, caused a significant increase in immediate responses to ovalbumin challenge when aspirated 2 hr before challenge, but not when aspirated immediately before sensitization 2 weeks earlier. Antigen-specific IgE was increased by Hettstedt PM(2.5) whether administered before sensitization or challenge. Airway responsiveness to methacholine aerosol and lung inflammatory cell numbers were significantly increased only in allergic mice exposed to Hettstedt PM(2.5) before challenge. Both Hettstedt and Zerbst PM(2.5) significantly increased lung injury parameters and proinflammatory cytokines. These results are consistent with epidemiologic findings and show that metal composition of ambient PM(2.5) influences the severity of allergic respiratory disease

    Precision surveying using very long baseline interferometry

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    Radio interferometry measurements were used to measure the vector baselines between large microwave radio antennas. A 1.24 km baseline in Massachusetts between the 36 meter Haystack Observatory antenna and the 18 meter Westford antenna of Lincoln Laboratory was measured with 5 mm repeatability in 12 separate experiments. Preliminary results from measurements of the 3,928 km baseline between the Haystack antenna and the 40 meter antenna at the Owens Valley Radio Observatory in California are presented
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