36,756 research outputs found
Generic Model Refactorings
Many modeling languages share some common concepts and principles. For example, Java, MOF, and UML share some aspects of the concepts\ud
of classes, methods, attributes, and inheritance. However, model\ud
transformations such as refactorings specified for a given language\ud
cannot be readily reused for another language because their related\ud
metamodels may be structurally different. Our aim is to enable a\ud
flexible reuse of model transformations across various metamodels.\ud
Thus, in this paper, we present an approach allowing the specification\ud
of generic model transformations, in particular refactorings, so\ud
that they can be applied to different metamodels. Our approach relies\ud
on two mechanisms: (1) an adaptation based mainly on the weaving\ud
of aspects; (2) the notion of model typing, an extension of object\ud
typing in the model-oriented context. We validated our approach by\ud
performing some experiments that consisted of specifying three well\ud
known refactorings (Encapsulate Field, Move Method, and Pull Up Method)\ud
and applying each of them onto three different metamodels (Java,\ud
MOF, and UML)
Thermoelectricity in Nanowires: A Generic Model
By employing a Boltzmann transport equation and using an energy and size
dependent relaxation time () approximation (RTA), we evaluate
self-consistently the thermoelectric figure-of-merit of a quantum wire
with rectangular cross-section. The inferred shows abrupt enhancement in
comparison to its counterparts in bulk systems. Still, the estimated for
the representative BiTe nanowires and its dependence on wire parameters
deviate considerably from those predicted by the existing RTA models with a
constant . In addition, we address contribution of the higher energy
subbands to the transport phenomena, the effect of chemical potential tuning on
, and correlation of with quantum size effects (QSEs). The obtained
results are of general validity for a wide class of systems and may prove
useful in the ongoing development of the modern thermoelectric applications.Comment: 15 pages, 6 figures; Dedicated to the memory of Amirkhan Qezell
Generic model of an atom laser
We present a generic model of an atom laser by including a pump and loss term
in the Gross-Pitaevskii equation. We show that there exists a threshold for the
pump above which the mean matter field assumes a non-vanishing value in
steady-state. We study the transient regime of this atom laser and find
oscillations around the stationary solution even in the presence of a loss
term. These oscillations are damped away when we introduce a position dependent
loss term. For this case we present a modified Thomas-Fermi solution that takes
into account the pump and loss. Our generic model of an atom laser is analogous
to the semi-classical theory of the laser.Comment: 15 pages, including 5 figures, submitted to Phys. Rev. A, revised
manuscript, file also available at
http://www.physik.uni-ulm.de/quan/users/kne
A generic model of dyadic social relationships
We introduce a model of dyadic social interactions and establish its
correspondence with relational models theory (RMT), a theory of human social
relationships. RMT posits four elementary models of relationships governing
human interactions, singly or in combination: Communal Sharing, Authority
Ranking, Equality Matching, and Market Pricing. To these are added the limiting
cases of asocial and null interactions, whereby people do not coordinate with
reference to any shared principle. Our model is rooted in the observation that
each individual in a dyadic interaction can do either the same thing as the
other individual, a different thing or nothing at all. To represent these three
possibilities, we consider two individuals that can each act in one out of
three ways toward the other: perform a social action X or Y, or alternatively
do nothing. We demonstrate that the relationships generated by this model
aggregate into six exhaustive and disjoint categories. We propose that four of
these categories match the four relational models, while the remaining two
correspond to the asocial and null interactions defined in RMT. We generalize
our results to the presence of N social actions. We infer that the four
relational models form an exhaustive set of all possible dyadic relationships
based on social coordination. Hence, we contribute to RMT by offering an answer
to the question of why there could exist just four relational models. In
addition, we discuss how to use our representation to analyze data sets of
dyadic social interactions, and how social actions may be valued and matched by
the agents
Level of Repair Analysis: A Generic Model
Given a product design and a repair network, a level of repair analysis (lora) determines for each component in the product (1) whether it should be discarded or repaired upon failure and (2) at which echelon in the repair network to do this. The objective of the lora is to minimize the total (variable and fixed) costs. We propose an ip model that generalizes the existing models, based on cases that we have seen in practice. Analysis of our model reveals that the integrality constraints on a large number of binary variables can be relaxed without yielding a fractional solution. As a result, we are able to solve problem instances of a realistic size in a couple of seconds on average. Furthermore, we suggest some improvements to the lora analysis in the current literature
A Generic Model of Contracts for Embedded Systems
We present the mathematical foundations of the contract-based model developed
in the framework of the SPEEDS project. SPEEDS aims at developing methods and
tools to support "speculative design", a design methodology in which
distributed designers develop different aspects of the overall system, in a
concurrent but controlled way. Our generic mathematical model of contract
supports this style of development. This is achieved by focusing on behaviors,
by supporting the notion of "rich component" where diverse (functional and
non-functional) aspects of the system can be considered and combined, by
representing rich components via their set of associated contracts, and by
formalizing the whole process of component composition
Efficient tunable generic model for fluid bilayer membranes
We present a model for the efficient simulation of generic bilayer membranes.
Individual lipids are represented by one head- and two tail-beads. By means of
simple pair potentials these robustly self-assemble to a fluid bilayer state
over a wide range of parameters, without the need for an explicit solvent. The
model shows the expected elastic behavior on large length scales, and its
physical properties (eg fluidity or bending stiffness) can be widely tuned via
a single parameter. In particular, bending rigidities in the experimentally
relevant range are obtained, at least within . The model is
naturally suited to study many physical topics, including self-assembly,
fusion, bilayer melting, lipid mixtures, rafts, and protein-bilayer
interactions.Comment: 4 Pages 4 Figure
A generic model for spouse's pensions with a view towards the calculation of liabilities
We introduce a generic model for spouse's pensions. The generic model allows
for the modeling of various types of spouse's pensions with payments commencing
at the death of the insured. We derive abstract formulas for cashflows and
liabilities corresponding to common types of spouse's pensions. We show how the
standard formulas from the Danish G82 concession can be obtained as a special
case of our generic model. We also derive expressions for liabilities for
spouse's pensions in models more advanced than found in the G82 concession. The
generic nature of our model and results furthermore enable the calculation of
cashflows and liabilities using simple estimates of marital behaviour among a
population
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