57,347 research outputs found
Web-GIS models: accomplishing modularity with aspects
Spatial concerns of Web geographical information systems (Web-GIS) are inherently crosscutting and volatile: crosscutting because they affect multiple functionalities of Web-GIS systems, and volatile because their status may change often. If these concerns are not modularized properly, the quality of Web-GIS services, particularly with regard to adaptation and evolution, can be severely compromised. This paper uses aspect-orientation to model crosscutting and volatile spatial concerns. By modeling both types of concerns, crosscutting and volatile, as candidate aspects, one can use dynamic weaving to add or remove them from a system at runtime. The aspect-oriented approach proposed starts with the identification and specification of crosscutting concerns and follows by composing these using modeling aspects using a transformation approach, an aspect-oriented modeling technique. The conflicts that can emerge due to the composition order are also taken into consideration. Finally, this paper proposes a set of reusable GIS crosscutting concerns, documenting them in a concern catalogue.Laboratorio de Investigación y Formación en Informática Avanzad
Exploiting a Goal-Decomposition Technique to Prioritize Non-functional Requirements
Business stakeholders need to have clear and realistic goals if they want to meet commitments in application development. As a consequence, at early stages they prioritize requirements. However, requirements do change. The effect of change forces the stakeholders to balance alternatives and reprioritize requirements accordingly. In this paper we discuss the problem of priorities to non-functional requirements subjected to change. We, then, propose an approach to help smooth the impact of such changes. Our approach favors the translation of nonoperational specifications into operational definitions that can be evaluated once the system is developed. It uses the goal-question-metric method as the major support to decompose non-operational specifications into operational ones. We claim that the effort invested in operationalizing NFRs helps dealing with changing requirements during system development. Based on\ud
this transformation and in our experience, we provide guidelines to prioritize volatile non-functional requirements
Identifying and Modelling Complex Workflow Requirements in Web Applications
Workflow plays a major role in nowadays business and therefore its
requirement elicitation must be accurate and clear for achieving the solution
closest to business’s needs. Due to Web applications popularity, the Web is becoming
the standard platform for implementing business workflows. In this
context, Web applications and their workflows must be adapted to market demands
in such a way that time and effort are minimize. As they get more popular,
they must give support to different functional requirements but also they
contain tangled and scattered behaviour. In this work we present a model-driven
approach for modelling workflows using a Domain Specific Language for Web
application requirement called WebSpec. We present an extension to WebSpec
based on Pattern Specifications for modelling crosscutting workflow requirements
identifying tangled and scattered behaviour and reducing inconsistencies
early in the cycle
Shuttle on-orbit contamination and environmental effects
Ensuring the compatibility of the space shuttle system with payloads and payload measurements is discussed. An extensive set of quantitative requirements and goals was developed and implemented by the space shuttle program management. The performance of the Shuttle system as measured by these requirements and goals was assessed partly through the use of the induced environment contamination monitor on Shuttle flights 2, 3, and 4. Contamination levels are low and generally within the requirements and goals established. Additional data from near-term payloads and already planned contamination measurements will complete the environment definition and allow for the development of contamination avoidance procedures as necessary for any payload
A Buffer Stocks Model for Stabilizing Price of Commodity under Limited Time of Supply and Continuous Consumption
Staple foods, in developing countries especially in Indonesia, have extremely volatile among harvest
and planting season caused by inelastic of supply-demand and price disparity. When a staple food is shortage
in market, it will trigger crisis of economics, political and social because it concerns with food security. This
paper develops a buffer stock model for stabilizing price of commodity under limited time of supply and
continuous consumption. The performance criterion of model will consider financial loss of producer, consumer
and government side when market is interfered by price-stabilization program and price-support program
simultaneously. The price fluctuation will be stabilized by market operation where buffer stocks are bought
from domestic and import supply point. This paper provides a price band policy that attempts to bound
domestic price variation between a set of upper and lower bounds on the level of domestic prices. We consider
three sets of problems reflecting different three prices elasticity from 4 period of supply and demand.
Numerical examples are found to be consistent with empirical estimates regarding the relationship price
elasticity with price band and with government budget for the agenda of assisting household to assure
availability a staple food with enough amounts at rational prices.
Keywords: buffer stocks, price band, stabilization, limited time of supply, staple foods
Modeling Impacts of Cold Climates on Vehicle Emissions
This project relates to the research thrust area of ‘environmental impact assessment,' specifically the impact of cold climates on vehicle exhaust emissions. Motor vehicles emit pollutants that are harmful to human. Emissions are thought to be elevated during engine cold starts. During winter, low-lying temperature inversion can trap vehicle emissions near the surface, leading to significantly elevated pollutant concentrations. Despite the importance, vehicle emissions data for cold climates are sparse and the accuracy of vehicle emissions model parameterizations for cold climates is not known. The goal of this project is to improve ability of EPA's Motor Vehicle Emission Simulator (MOVES) model to simulate cold start emissions in cold climate
A Framework for Evaluating Model-Driven Self-adaptive Software Systems
In the last few years, Model Driven Development (MDD), Component-based
Software Development (CBSD), and context-oriented software have become
interesting alternatives for the design and construction of self-adaptive
software systems. In general, the ultimate goal of these technologies is to be
able to reduce development costs and effort, while improving the modularity,
flexibility, adaptability, and reliability of software systems. An analysis of
these technologies shows them all to include the principle of the separation of
concerns, and their further integration is a key factor to obtaining
high-quality and self-adaptable software systems. Each technology identifies
different concerns and deals with them separately in order to specify the
design of the self-adaptive applications, and, at the same time, support
software with adaptability and context-awareness. This research studies the
development methodologies that employ the principles of model-driven
development in building self-adaptive software systems. To this aim, this
article proposes an evaluation framework for analysing and evaluating the
features of model-driven approaches and their ability to support software with
self-adaptability and dependability in highly dynamic contextual environment.
Such evaluation framework can facilitate the software developers on selecting a
development methodology that suits their software requirements and reduces the
development effort of building self-adaptive software systems. This study
highlights the major drawbacks of the propped model-driven approaches in the
related works, and emphasise on considering the volatile aspects of
self-adaptive software in the analysis, design and implementation phases of the
development methodologies. In addition, we argue that the development
methodologies should leave the selection of modelling languages and modelling
tools to the software developers.Comment: model-driven architecture, COP, AOP, component composition,
self-adaptive application, context oriented software developmen
Concept for a research project in early crustal genesis
Planetary volatiles, physical and chemical planetary evolution, surface processes, planetary formation, metallogenesis, crustal features and their development, tectonics, and paleobiology are discussed
Physiological modeling of isoprene dynamics in exhaled breath
Human breath contains a myriad of endogenous volatile organic compounds
(VOCs) which are reflective of ongoing metabolic or physiological processes.
While research into the diagnostic potential and general medical relevance of
these trace gases is conducted on a considerable scale, little focus has been
given so far to a sound analysis of the quantitative relationships between
breath levels and the underlying systemic concentrations. This paper is devoted
to a thorough modeling study of the end-tidal breath dynamics associated with
isoprene, which serves as a paradigmatic example for the class of low-soluble,
blood-borne VOCs.
Real-time measurements of exhaled breath under an ergometer challenge reveal
characteristic changes of isoprene output in response to variations in
ventilation and perfusion. Here, a valid compartmental description of these
profiles is developed. By comparison with experimental data it is inferred that
the major part of breath isoprene variability during exercise conditions can be
attributed to an increased fractional perfusion of potential storage and
production sites, leading to higher levels of mixed venous blood concentrations
at the onset of physical activity. In this context, various lines of supportive
evidence for an extrahepatic tissue source of isoprene are presented.
Our model is a first step towards new guidelines for the breath gas analysis
of isoprene and is expected to aid further investigations regarding the
exhalation, storage, transport and biotransformation processes associated with
this important compound.Comment: 14 page
Physiological modeling of isoprene dynamics in exhaled breath
Human breath contains a myriad of endogenous volatile organic compounds
(VOCs) which are reflective of ongoing metabolic or physiological processes.
While research into the diagnostic potential and general medical relevance of
these trace gases is conducted on a considerable scale, little focus has been
given so far to a sound analysis of the quantitative relationships between
breath levels and the underlying systemic concentrations. This paper is devoted
to a thorough modeling study of the end-tidal breath dynamics associated with
isoprene, which serves as a paradigmatic example for the class of low-soluble,
blood-borne VOCs.
Real-time measurements of exhaled breath under an ergometer challenge reveal
characteristic changes of isoprene output in response to variations in
ventilation and perfusion. Here, a valid compartmental description of these
profiles is developed. By comparison with experimental data it is inferred that
the major part of breath isoprene variability during exercise conditions can be
attributed to an increased fractional perfusion of potential storage and
production sites, leading to higher levels of mixed venous blood concentrations
at the onset of physical activity. In this context, various lines of supportive
evidence for an extrahepatic tissue source of isoprene are presented.
Our model is a first step towards new guidelines for the breath gas analysis
of isoprene and is expected to aid further investigations regarding the
exhalation, storage, transport and biotransformation processes associated with
this important compound.Comment: 14 page
- …