7,357 research outputs found
An improved support vector regression and its modelling of manoeuvring performance in multidisciplinary ship design optimization
In this paper, the combination of the Laplace loss function and Support Vector Regression (SVR) are presented for the estimation of manoeuvring performance in multidisciplinary ship design optimization, and a new SVR algorithm was proposed, which has only one parameter to control the errors and automatically minimized with v, and adds b2/2 b to the item of confidence interval. It is shown that the proposed SVR algorithm in conjunction with the Laplace loss function can estimate the ship manoeuvring performance appropriately compared to the simulation results with Napa software and other approximation methods such as Artificial Neural Network (ANN) and classic SVR. In this article, we also gather enough ship information about the offshore support vessel; the Latin Hypercube Design is employed to explore the design space. Instead of requiring the evaluation of expensive simulation codes, we establish the metamedels of ship manoeuvring performance; all the numerical results show the effectiveness and practicability of the new approximation algorithms
Virtual integration platform for computational fluid dynamics
Computational Fluid Dynamics (CFD) tools used in shipbuilding industry involve multiple disciplines, such as resistance, manoeuvring, and cavitation. Traditionally, the analysis was performed separately and sequentially in each discipline, which often resulted in conflict and inconsistency of hydrodynamic prediction. In an effort to solve such problems for future CFD computations, a Virtual Integration Platform (VIP) has been developed in the University of Strathclyde within two EU FP6 projects - VIRTUE and SAFEDOR1. The VIP provides a holistic collaborative environment for designers with features such as Project/Process Management, Distributed Tools Integration, Global Optimisation, Version Management, and Knowledge Management. These features enhance collaboration among customers, ship design companies, shipyards, and consultancies not least because they bring together the best expertise and resources around the world. The platform has been tested in seven European ship design companies including consultancies. Its main functionalities along with advances are presented in this paper with two industrial applications
Self-Evaluation Applied Mathematics 2003-2008 University of Twente
This report contains the self-study for the research assessment of the Department of Applied Mathematics (AM) of the Faculty of Electrical Engineering, Mathematics and Computer Science (EEMCS) at the University of Twente (UT). The report provides the information for the Research Assessment Committee for Applied Mathematics, dealing with mathematical sciences at the three universities of technology in the Netherlands. It describes the state of affairs pertaining to the period 1 January 2003 to 31 December 2008
Multidisciplinary Observing in the World Ocean\u27s Oxygen Minimum Zone Regions: From Climate to Fish - The VOICE Initiative
Multidisciplinary ocean observing activities provide critical ocean information to satisfy ever-changing socioeconomic needs and require coordinated implementation. The upper oxycline (transition between high and low oxygen waters) is fundamentally important for the ecosystem structure and can be a useful proxy for multiple observing objectives connected to eastern boundary systems (EBSs) that neighbor oxygen minimum zones (OMZs). The variability of the oxycline and its impact on the ecosystem (VOICE) initiative demonstrates how societal benefits drive the need for integration and optimization of biological, biogeochemical, and physical components of regional ocean observing related to EBS. In liaison with the Global Ocean Oxygen Network, VOICE creates a roadmap toward observation-model syntheses for a comprehensive understanding of selected oxycline-dependent objectives. Local to global effects, such as habitat compression or deoxygenation trends, prompt for comprehensive observing of the oxycline on various space and time scales, and for an increased awareness of its impact on ecosystem services. Building on the Framework for Ocean Observing (FOO), we present a first readiness level assessment for ocean observing of the oxycline in EBS. This was to determine current ocean observing design and future needs in EBS regions (e.g., the California Current System, the Equatorial Eastern Pacific off Ecuador, the Peru-Chile Current system, the Northern Benguela off Namibia, etc.) building on the FOO strategy. We choose regional champions to assess the ocean observing design elements proposed in the FOO, namely, requirement processes, coordination of observational elements, and data management and information products and the related best practices. The readiness level for the FOO elements was derived for each EBS through a similar and very general ad hoc questionnaire. Despite some weaknesses in the questionnaire design and its completion, an assessment was achievable. We found that fisheries and ecosystem management are a societal requirement for all regions, but maturity levels of observational elements and data management and information products differ substantially. Identification of relevant stakeholders, developing strategies for readiness level improvements, and building and sustaining infrastructure capacity to implement these strategies are fundamental milestones for the VOICE initiative over the next 2-5 years and beyond
From Network to Web dimension in supply chain management
Cette thèse soutient que la dimension réseau, étant actuellement la portée du domaine de la gestion de chaîne logistique, contraint l’avancement de ce domaine et restreint des innovations conceptuelles et fondamentales capables d’adresser les grands défis économiques, environnementaux et sociaux. Les concepts de chaîne et de réseau ne reflètent pas la complexité des flux physiques, informationnels et financiers générés par les interactions qui ont lieu dans des réseaux interconnectés. Ces concepts n’offrent pas les fondations théoriques pour supporter des interventions allant au-delà d’un seul réseau et laissent échapper des opportunités nécessitant une vision multi-réseau. Ainsi, la dimension “web”, celle des réseaux de réseaux, est proposée comme une extension de la dimension réseau. Cette extension peut être vue comme l’étape naturelle suivante dans la progression qui a commencé par le niveau de gestion des opérations internes, est passée au niveau de la chaîne logistique et se trouve actuellement au niveau du réseau logistique. Après l’investigation théorique des raisons et de la façon d’intégrer la dimension web dans le domaine de la gestion de la chaîne logistique, la thèse étudie des implications importantes de cette intégration sur la collaboration inter-organisationnelle et le processus de prise de décision dans des environnements de webs logistiques. Elle démontre, en exploitant l’exemple des réseaux interconnectés ouverts, des potentialités inimaginables sans une vision web. Une méthodologie de conception d’un modèle de simulation permettant l’évaluation et la comparaison des webs ouverts par rapport aux webs existants est proposée. Puisque l’aide à la décision est une composante importante de la gestion de la chaîne logistique, la thèse contribue à déterminer les besoins des gestionnaires et à identifier les lignes directrices de la conception des outils d’aide à la décision offrant le support adéquat pour faire face aux défis et à la complexité des webs logistiques. Ces lignes directrices ont été compilées dans un cadre de conception des logiciels d’aide à la décision supportant la dimension web. Ce cadre est exploité pour développer quatre applications logicielles offrant aux praticiens et aux chercheurs des outils nécessaires pour étudier, analyser et démêler la complexité des webs logistiques.This thesis argues that the network dimension as the current scope of supply chain management is confining the evolution of this field and restricting the conceptual and fundamental innovations required for addressing the major challenges imposed by the evolution of markets and the increased intricacies of business relationships. The concepts of chain and network are limitative when attempting to represent the complexity of physical, informational and financial flows resulting from the interactions occurring in overlapping networks. They lack the theoretical foundations necessary to explain and encompass initiatives that go beyond a single chain or network. They also lead to overlook substantial opportunities that require beyond a network vision. Therefore, the “web” dimension, as networks of networks, is proposed as an extension to the network dimension in supply chain management. This new scope is the natural next step in the progression from the internal operations management level to the supply chain level and then to the supply network level. After a theoretical investigation of why and how the web dimension should be integrated into the supply chain management field, the thesis studies and discusses important implications of this integration on inter-organisational collaboration and of the decision-making processes in the logistic web environments. It demonstrates through the example of open interconnected logistic webs some of the potentials that cannot be imagined without a web vision. A methodology for designing a simulation model to assess the impact of such open webs versus existing webs is proposed. Since decision support is a key element in supply chain management, the thesis contributes to determine the needs of supply chain managers and identify the important axes for designing decision support systems that provide adequate assistance in dealing with the challenges and complexity presented by logistic web environments. The identified elements result in the establishment of a foundation for designing software solutions required to handle the challenges revealed by the web dimension. This conceptual framework is applied to the prototyping of four applications that have the potential of providing practitioners and researchers with the appropriate understanding and necessary tools to deal with the complexity of logistics webs
Improving National and Homeland Security through a proposed Laboratory for Information Globalization and Harmonization Technologies (LIGHT)
A recent National Research Council study found that: "Although there are many private and public databases that
contain information potentially relevant to counter terrorism programs, they lack the necessary context definitions
(i.e., metadata) and access tools to enable interoperation with other databases and the extraction of meaningful and
timely information" [NRC02, p.304, emphasis added] That sentence succinctly describes the objectives of this
project. Improved access and use of information are essential to better identify and anticipate threats, protect
against and respond to threats, and enhance national and homeland security (NHS), as well as other national
priority areas, such as Economic Prosperity and a Vibrant Civil Society (ECS) and Advances in Science and
Engineering (ASE). This project focuses on the creation and contributions of a Laboratory for Information
Globalization and Harmonization Technologies (LIGHT) with two interrelated goals:
(1) Theory and Technologies: To research, design, develop, test, and implement theory and technologies for
improving the reliability, quality, and responsiveness of automated mechanisms for reasoning and resolving semantic
differences that hinder the rapid and effective integration (int) of systems and data (dmc) across multiple
autonomous sources, and the use of that information by public and private agencies involved in national and
homeland security and the other national priority areas involving complex and interdependent social systems (soc).
This work builds on our research on the COntext INterchange (COIN) project, which focused on the integration
of diverse distributed heterogeneous information sources using ontologies, databases, context mediation algorithms,
and wrapper technologies to overcome information representational conflicts. The COIN approach makes it
substantially easier and more transparent for individual receivers (e.g., applications, users) to access and exploit
distributed sources. Receivers specify their desired context to reduce ambiguities in the interpretation of information
coming from heterogeneous sources. This approach significantly reduces the overhead involved in the integration of
multiple sources, improves data quality, increases the speed of integration, and simplifies maintenance in an
environment of changing source and receiver context - which will lead to an effective and novel distributed
information grid infrastructure. This research also builds on our Global System for Sustainable Development
(GSSD), an Internet platform for information generation, provision, and integration of multiple domains, regions,
languages, and epistemologies relevant to international relations and national security.
(2) National Priority Studies: To experiment with and test the developed theory and technologies on practical
problems of data integration in national priority areas. Particular focus will be on national and homeland security,
including data sources about conflict and war, modes of instability and threat, international and regional
demographic, economic, and military statistics, money flows, and contextualizing terrorism defense and response.
Although LIGHT will leverage the results of our successful prior research projects, this will be the first research
effort to simultaneously and effectively address ontological and temporal information conflicts as well as
dramatically enhance information quality. Addressing problems of national priorities in such rapidly changing
complex environments requires extraction of observations from disparate sources, using different interpretations, at
different points in times, for different purposes, with different biases, and for a wide range of different uses and
users. This research will focus on integrating information both over individual domains and across multiple domains.
Another innovation is the concept and implementation of Collaborative Domain Spaces (CDS), within which
applications in a common domain can share, analyze, modify, and develop information. Applications also can span
multiple domains via Linked CDSs. The PIs have considerable experience with these research areas and the
organization and management of such large scale international and diverse research projects.
The PIs come from three different Schools at MIT: Management, Engineering, and Humanities, Arts & Social
Sciences. The faculty and graduate students come from about a dozen nationalities and diverse ethnic, racial, and
religious backgrounds. The currently identified external collaborators come from over 20 different organizations
and many different countries, industrial as well as developing. Specific efforts are proposed to engage even more
women, underrepresented minorities, and persons with disabilities.
The anticipated results apply to any complex domain that relies on heterogeneous distributed data to address and
resolve compelling problems. This initiative is supported by international collaborators from (a) scientific and
research institutions, (b) business and industry, and (c) national and international agencies. Research products
include: a System for Harmonized Information Processing (SHIP), a software platform, and diverse applications in
research and education which are anticipated to significantly impact the way complex organizations, and society in
general, understand and manage critical challenges in NHS, ECS, and ASE
Improving National and Homeland Security through a proposed Laboratory for nformation Globalization and Harmonization Technologies (LIGHT)
A recent National Research Council study found that: "Although there are many private and public databases that
contain information potentially relevant to counter terrorism programs, they lack the necessary context definitions
(i.e., metadata) and access tools to enable interoperation with other databases and the extraction of meaningful and
timely information" [NRC02, p.304, emphasis added] That sentence succinctly describes the objectives of this
project. Improved access and use of information are essential to better identify and anticipate threats, protect
against and respond to threats, and enhance national and homeland security (NHS), as well as other national
priority areas, such as Economic Prosperity and a Vibrant Civil Society (ECS) and Advances in Science and
Engineering (ASE). This project focuses on the creation and contributions of a Laboratory for Information
Globalization and Harmonization Technologies (LIGHT) with two interrelated goals:
(1) Theory and Technologies: To research, design, develop, test, and implement theory and technologies for
improving the reliability, quality, and responsiveness of automated mechanisms for reasoning and resolving semantic
differences that hinder the rapid and effective integration (int) of systems and data (dmc) across multiple
autonomous sources, and the use of that information by public and private agencies involved in national and
homeland security and the other national priority areas involving complex and interdependent social systems (soc).
This work builds on our research on the COntext INterchange (COIN) project, which focused on the integration of
diverse distributed heterogeneous information sources using ontologies, databases, context mediation algorithms,
and wrapper technologies to overcome information representational conflicts. The COIN approach makes it
substantially easier and more transparent for individual receivers (e.g., applications, users) to access and exploit
distributed sources. Receivers specify their desired context to reduce ambiguities in the interpretation of information
coming from heterogeneous sources. This approach significantly reduces the overhead involved in the integration of
multiple sources, improves data quality, increases the speed of integration, and simplifies maintenance in an
environment of changing source and receiver context - which will lead to an effective and novel distributed
information grid infrastructure. This research also builds on our Global System for Sustainable Development
(GSSD), an Internet platform for information generation, provision, and integration of multiple domains, regions,
languages, and epistemologies relevant to international relations and national security.
(2) National Priority Studies: To experiment with and test the developed theory and technologies on practical
problems of data integration in national priority areas. Particular focus will be on national and homeland security,
including data sources about conflict and war, modes of instability and threat, international and regional
demographic, economic, and military statistics, money flows, and contextualizing terrorism defense and response.
Although LIGHT will leverage the results of our successful prior research projects, this will be the first research
effort to simultaneously and effectively address ontological and temporal information conflicts as well as
dramatically enhance information quality. Addressing problems of national priorities in such rapidly changing
complex environments requires extraction of observations from disparate sources, using different interpretations, at
different points in times, for different purposes, with different biases, and for a wide range of different uses and
users. This research will focus on integrating information both over individual domains and across multiple domains.
Another innovation is the concept and implementation of Collaborative Domain Spaces (CDS), within which
applications in a common domain can share, analyze, modify, and develop information. Applications also can span
multiple domains via Linked CDSs. The PIs have considerable experience with these research areas and the
organization and management of such large scale international and diverse research projects.
The PIs come from three different Schools at MIT: Management, Engineering, and Humanities, Arts & Social
Sciences. The faculty and graduate students come from about a dozen nationalities and diverse ethnic, racial, and
religious backgrounds. The currently identified external collaborators come from over 20 different organizations and
many different countries, industrial as well as developing. Specific efforts are proposed to engage even more
women, underrepresented minorities, and persons with disabilities.
The anticipated results apply to any complex domain that relies on heterogeneous distributed data to address and
resolve compelling problems. This initiative is supported by international collaborators from (a) scientific and
research institutions, (b) business and industry, and (c) national and international agencies. Research products
include: a System for Harmonized Information Processing (SHIP), a software platform, and diverse applications in
research and education which are anticipated to significantly impact the way complex organizations, and society in
general, understand and manage critical challenges in NHS, ECS, and ASE
Orthogonal decomposition as a design tool: With application to a mixing impeller
Digital manufacturing eliminates the expense and time required to develop custom products. By utilizing this technology, designers can quickly create a customized product specifically for their performance needs. But the timescale and expense from the engineering design workflows used to develop these customized products have not been adapted from the workflows used in mass production. In many cases these customized designs build upon already successful mass-produced products that were developed using conventional engineering design workflows. Many times as part of this conventional design process significant time is spent creating and validating high fidelity models that accurately predict the performance of the final design. These existing validated high fidelity models used for the mass-produced design can be reused for analysis and design of unknown products. This thesis explores the integration of reduced order modeling and detailed analysis into the engineering design workflow developing a customized design using digital manufacturing. Specifically, detailed analysis is coupled with proper orthogonal decomposition to enable the exploration of the design space while simultaneously shaping the model representing the design. This revised workflow is examined using the design of a laboratory scale overhead mixer impeller. The case study presented here is compared with the design of the Kar Dynamic Mixer impeller developed by The Dow Chemical Company. The result of which is a customized design for a refined set of operating conditions with improved performance
Stress and frequency optimization of prismatic sandwich beams with joints: Performance improvements through topology optimization
Prismatic sandwich panels fabricated from metals offer a compelling
alternative to more traditional panels across diverse industries, primarily due
to their superior strength-to-weight ratio. Although several core types were
proposed in the past, further improvements in performance could be achieved by
devising the topology of the core through a topology optimization framework,
which is explored in this article for the first time. Another novelty is the
inclusion of joints between the sandwich beams and its surroundings in the
analysis and optimization. Stress is minimized under uniform pressure loading
on the beams and natural frequency maximized using the Method of Moving
Asymptotes. The results are compared with X-core, Y-core, corrugated-core, and
web-core sandwich beams, a few conventional prismatic sandwich types, which are
optimized using a prominent global evolutionary algorithm. Manufacturing
requirements are considered through practical limitations on the design
variables. It is shown that structures produced by topology optimization
outperform the conventional sandwich beams by up to 44% at intermediate to high
mass levels, where volume fraction is between 0.2 and 0.4, but often through
increased topological complexity. The new core topologies bear a certain
resemblance with the conventional core types, underscoring engineering
ingenuity that went into their development over the years. The topology of the
optimized joints differs from the conventional joint. The results also show
some limitations of the topology optimization framework, for example that it
does not offer better-performing beams for volume fractions below 0.2.Comment: 17 pages, 3 tables, 19 figures, journal pape
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