168 research outputs found
Designing a Framework to Handle Context Information
In the recent years, a number of context-aware frameworks have been proposed to facilitate the development of context-aware applications. From the experience gained, in this paper we explore the design principles that contextaware platforms should conform to, the functionalities they have to provide and the technologies and tools that can be used for their implementation. Subsequently, we propose a context-aware framework and describe the architecture it adopts, making our own technological selection from the options previously identified
Abstract State Machines 1988-1998: Commented ASM Bibliography
An annotated bibliography of papers which deal with or use Abstract State
Machines (ASMs), as of January 1998.Comment: Also maintained as a BibTeX file at http://www.eecs.umich.edu/gasm
A framework for developing finite element codes for multi- disciplinary applications
The world of computing simulation has experienced great progresses in recent years and requires
more exigent multidisciplinary challenges to satisfy the new upcoming demands. Increasing the
importance of solving multi-disciplinary problems makes developers put more attention to these
problems and deal with difficulties involved in developing software in this area.
Conventional finite element codes have several difficulties in dealing with multi-disciplinary
problems. Many of these codes are designed and implemented for solving a certain type of problems,
generally involving a single field. Extending these codes to deal with another field of analysis
usually consists of several problems and large amounts of modifications and implementations.
Some typical difficulties are: predefined set of degrees of freedom per node, data structure with
fixed set of defined variables, global list of variables for all entities, domain based interfaces, IO
restriction in reading new data and writing new results and algorithm definition inside the code.
A common approach is to connect different solvers via a master program which implements the
interaction algorithms and also transfers data from one solver to another. This approach has been
used successfully in practice but results duplicated implementation and redundant overhead of
data storing and transferring which may be significant depending to the solvers data structure.
The objective of this work is to design and implement a framework for building multi-disciplinary
finite element programs. Generality, reusability, extendibility, good performance and memory efficiency
are considered to be the main points in design and implementation of this framework.
Preparing the structure for team development is another objective because usually a team of experts
in different fields are involved in the development of multi-disciplinary code.
Kratos, the framework created in this work, provides several tools for easy implementation
of finite element applications and also provides a common platform for natural interaction of its
applications in different ways. This is done not only by a number of innovations but also by
collecting and reusing several existing works.
In this work an innovative variable base interface is designed and implemented which is used
at different levels of abstraction and showed to be very clear and extendible. Another innovation
is a very efficient and flexible data structure which can be used to store any type of data in a
type-safe manner. An extendible IO is also created to overcome another bottleneck in dealing with
multi-disciplinary problems. Collecting different concepts of existing works and adapting them
to coupled problems is considered to be another innovation in this work. Examples are using an
interpreter, different data organizations and variable number of dofs per node. The kernel and
application approach is used to reduce the possible conflicts arising between developers of different
fields and layers are designed to reflect the working space of different developers also considering
their programming knowledge. Finally several technical details are applied in order to increase the
performance and efficiency of Kratos which makes it practically usable.
This work is completed by demonstrating the framework’s functionality in practice. First some
classical single field applications like thermal, fluid and structural applications are implemented and
used as benchmark to prove its performance. These applications are used to solve coupled problems
in order to demonstrate the natural interaction facility provided by the framework. Finally some
less classical coupled finite element algorithms are implemented to show its high flexibility and
extendibility
Protection and Synchronization in Actor Systems
This paper presents a unified method [called ENCASING] for dealing with the closely related issues of synchronization and protection in actor systems [Hewitt et al. 1973a, 1973b, 1974a; Greif and Hewitt 1975]. Actors are a semantic concept in which no active process is ever allowed to treat anything as an object. Instead a polite request must be extended to accomplish what the activator [process] desires. Actors enable us to define effective and efficient protection schemes. Vulnerable actors can be protected before being passed out by ENCASING their behavior in a guardian which applies appropriate checks before invoking the protected actor. Protected actors can be freely passed out since they work only for actors which have the authority to use them where authority can be decided by an arbitrary procedure. Synchronization can be viewed as a [time-variant] kind of protection in which access is only allowed to the encased actor when it is safe to do so.MIT Artificial Intelligence Laborator
Pierre Duhemâs philosophy and history of science
LEITE (FĂĄbio Rodrigo) â STOFFEL (Jean-François), Introduction (pp. 3-6). BARRA (Eduardo Salles de O.) â SANTOS (Ricardo Batista dos), Duhemâs analysis of Newtonian method and the logical priority of physics over metaphysics (pp. 7-19). BORDONI (Stefano), The French roots of Duhemâs early historiography and epistemology (pp. 20-35). CHIAPPIN (JosĂ© R. N.) â LARANJEIRAS (CĂĄssio Costa), Duhemâs critical analysis of mechaÂniÂcism and his defense of a formal conception of theoretical phyÂsics (pp. 36-53). GUEGUEN (Marie) â PSILLOS (Stathis), Anti-Âscepticism and epistemic humility in Pierre Duhemâs philosophy of science (pp. 54-72). LISTON (Michael), Duhem : images of science, historical continuity, and the first crisis in physics (pp. 73-84). MAIOCCHI (Roberto), Duhem in pre-war Italian philosÂophy : the reasons of an absence (pp. 85-92). HERNĂNDEZ MĂRQUEZ (VĂctor Manuel), Was Pierre Duhem an «esprit de finesse» ? (pp. 93-107). NEEDHAM (Paul), Was Duhem justified in not distinguishing between physical and chemical atomism ? (pp. 108-111). OLGUIN (Roberto Estrada), «Bon sens» and «noĂ»s» (pp. 112-126). OLIVEIRA (Amelia J.), Duhemâs legacy for the change in the historiography of science : An analysis based on Kuhnâs writings (pp. 127-139). PRĂNCIPE (JoĂŁo), PoincarĂ© and Duhem : Resonances in their first epistemological reflecÂtions (pp. 140-156). MONDRAGON (DamiĂĄn Islas), Book review of «Pierre Duhem : entre fĂsica y metafĂsica» (pp. 157-159). STOFFEL (Jean-François), Book review of P. Duhem : «La thĂ©orie physique : son objet, sa structure» / edit. by S. Roux (pp. 160-162). STOFFEL (Jean-François), Book review of St. Bordoni : «When historiography met epistemology» (pp. 163-165)
CItyMaker:
Due to its complexity, the evolution of cities is something that is difficult to predict and planning new developments for cities is therefore a difficult task. This complexity can be identified on two levels: on a micro level, it emerges from the multiple relations between the many components and actors in cities, whereas on a macro level it stems from the geographical, social and economic relations between cities. However, many of these relations can be measured.
The design of plans for cities can only be improved if designers are able to address measurements of some of the relationships between the components of cities during the design process. These measurements are called urban indicators. By calculating such measurements, designers can grasp the meaning of the changes being proposed, not just as simple alternative layouts, but also in terms of the changes in indicators adding a qualitative perception.
This thesis presents a method and a set of tools to generate alternative solutions for an urban context. The method proposes the use of a combined set of design patterns encoding typical design moves used by urban designers. The combination of patterns generates different layouts which can be adjusted by manipulating several parameters in relation to updated urban indicators. The patterns were developed from observation of typical urban design procedures, first encoded as discursive grammars and later translated into parametric design patterns. The CItyMaker method and tools allows the designer to compose a design solution from a set of programmatic premises and fine-tune it by pulling parameters whilst checking the changes in urban indicators. These tools improve the designerâs awareness of the consequences of their design moves
CItyMaker
Due to its complexity, the evolution of cities is something that is difficult to predict and planning new developments for cities is therefore a difficult task. This complexity can be identified on two levels: on a micro level, it emerges from the multiple relations between the many components and actors in cities, whereas on a macro level it stems from the geographical, social and economic relations between cities. However, many of these relations can be measured.
The design of plans for cities can only be improved if designers are able to address measurements of some of the relationships between the components of cities during the design process. These measurements are called urban indicators. By calculating such measurements, designers can grasp the meaning of the changes being proposed, not just as simple alternative layouts, but also in terms of the changes in indicators adding a qualitative perception.
This thesis presents a method and a set of tools to generate alternative solutions for an urban context. The method proposes the use of a combined set of design patterns encoding typical design moves used by urban designers. The combination of patterns generates different layouts which can be adjusted by manipulating several parameters in relation to updated urban indicators. The patterns were developed from observation of typical urban design procedures, first encoded as discursive grammars and later translated into parametric design patterns. The CItyMaker method and tools allows the designer to compose a design solution from a set of programmatic premises and fine-tune it by pulling parameters whilst checking the changes in urban indicators. These tools improve the designerâs awareness of the consequences of their design moves
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