389,478 research outputs found
Negotiating requirements for COTS-based systems
No full textSelecting COTS products is a process that inherently involves tradeoffs. In this
position paper, we highlight the challenges of the requirements process for COTS-based
system where the negotiation of requirements plays a critical task. In particular, it is
necessary to perform a careful balancing between stakeholders requirements and COTS
features. We analyse the processes of COTS matching and balancing using a goal-driven
approach
Challenges in COTS decision-making: a goal-driven requirements engineering perspective
No full textThis position paper outlines the problems and risks of selecting COTS products. In particular, we highlight the challenges of the decision-making process where requirements specification plays an essential role to evaluate and compare products features. It is necessary to perform a careful balancing between requirements and COTS features. Customers may have to compromise on requirements not satisfied by any available product or request products modifications. We analyse the problems and risks arising in the selection process and review related work. We argue that a goal-oriented approach can support an effective balancing between requirements and COTS feature during the decision-making
Time management issues in COTS distributed simulation: A case study
No full textCommercial off-the-shelf (COTS) simulation packages are widely used in industry. Several international groups are currently investigating techniques to integrate distributed simulation facilities in these packages. Through the use of a case study developed with the Ford Motor Company, this paper investigates time management issues in COTS simulation packages. Time management is classified on the basis of the ordering of events that are externally produced to a federate and the ordering of these with events that occur within a COTS simulation package federate. Several approaches to the latter are discussed and one approach is presented as the most effective. Finally the paper presents a bounded buffer problem and proposes the classification of information sharing with respect to the certification of solution
A comparison of CMB- and HLA-based approaches to type I interoperability reference model problems for COTS-based distributed simulation
No full textCommercial-off-the-shelf (COTS) simulation packages (CSPs) are software used by many simulation modellers to build and experiment with models of various systems in domains such as manufacturing, health, logistics and commerce. COTS distributed simulation deals with the interoperation of CSPs and their models. Such interoperability has been classified into six interoperability reference models. As part of an on-going standardisation effort, this paper introduces the COTS Simulation Package Emulator, a proposed benchmark that can be used to investigate Type I interoperability problems in COTS distributed simulation. To demonstrate its use, two approaches to this form of interoperability are discussed, an implementation of the CMB conservative algorithm, an example of a so-called “light” approach, and an implementation of the HLA TAR algorithm, an example of a so-called “heavy” approach. Results from experimentation over four federation topologies are presented and it is shown the HLA approach out performs the CMB approach in almost all cases. The paper concludes that the CSPE benchmark is a valid basis from which the most efficient approach to Type I interoperability problems for COTS distributed simulation can be discovered
Integrating heterogeneous distributed COTS discrete-event simulation packages: An emerging standards-based approach
No full textThis paper reports on the progress made toward the emergence of standards to support the integration of heterogeneous discrete-event simulations (DESs) created in specialist support tools called commercial-off-the-shelf (COTS) discrete-event simulation packages (CSPs). The general standard for heterogeneous integration in this area has been developed from research in distributed simulation and is the IEEE 1516 standard The High Level Architecture (HLA). However, the specific needs of heterogeneous CSP integration require that the HLA is augmented by additional complementary standards. These are the suite of CSP interoperability (CSPI) standards being developed under the Simulation Interoperability Standards Organization (SISO-http://www.sisostds.org) by the CSPI Product Development Group (CSPI-PDG). The suite consists of several interoperability reference models (IRMs) that outline different integration needs of CSPI, interoperability frameworks (IFs) that define the HLA-based solution to each IRM, appropriate data exchange representations to specify the data exchanged in an IF, and benchmarks termed CSP emulators (CSPEs). This paper contributes to the development of the Type I IF that is intended to represent the HLA-based solution to the problem outlined by the Type I IRM (asynchronous entity passing) by developing the entity transfer specification (ETS) data exchange representation. The use of the ETS in an illustrative case study implemented using a prototype CSPE is shown. This case study also allows us to highlight the importance of event granularity and lookahead in the performance and development of the Type I IF, and to discuss possible methods to automate the capture of appropriate values of lookahead
COTS simulation package (CSP) interoperability - A solution to synchronous entity passing
No full textIn this paper we examine Commercial-Off-The- Shelf (COTS) Simulation Package (CSP) interoperability for one type of distributed simulation problem, namely synchronous entity passing. Synchronous entity passing is also referred to as the bounded buffer interoperability reference model. It deals with the case where for entities passed between models the receiving queue is bounded or the receiving workstation has limited capacity. This means the sending model must check the status of the receiving model before it can send entities. Correspondingly, the receiving model should update the status information dynamically when it changes. Similar to the work done on asynchronous entity passing, the High Level Architecture is chosen as the underlying standard to support reuse and interoperability. To simplify the integration of the CSP and the HLA, a middleware layer called DSManager is provided. Some new problems generated for synchronous entity passing are discussed and solutions are proposed together with a description of their implementation. Two sets of experiments are conducted to evaluate the solutions using a CSP Emulator (CSPE) which supports both standalone and distributed simulation
A Dependable Architecture for COTS-Based Software Systems using Protective Wrappers
No full textCommercial off-the-shelf (COTS) software components are built to be used as black boxes that cannot be modified. The specific context in whichthese COTS components are employed is not known to their developers. Whenintegrating such COTS components into systems, which have high dependability requirements, there may be mismatches between the failure assumptions of these components and the rest of the system. For resolving these mismatches, system integrators must rely on techniques that are external to the COTS software components. In this paper, we combine the concepts of an idealised architectural component and protective wrappers to develop an architectural solution that provides an effective and systematic way for building dependable software systems from COTS software components
An analysis of internal/external event ordering strategies for COTS distributed simulation
No full textDistributed simulation is a technique that is used to link together several models so that they can work together (or interoperate) as a single model. The High Level Architecture (HLA) (IEEE 1516.2000) is the de facto standard that defines the technology for this interoperation. The creation of a distributed simulation of models developed in COTS Simulation Packages (CSPs) is of interest. The motivation is to attempt to reduce lead times of simulation projects by reusing models that have already been developed. This paper discusses one of the issues involved in distributed simulation with CSPs. This is the issue of synchronising data sent between models with the simulation of a model by a CSP, the so-called external/internal event ordering problem. The motivation is that the particular algorithm employed can represent a significant overhead on performance
Resolving Architectural Mismatches of COTS Through Architectural Reconciliation
No full textThe integration of COTS components into a system under development entails architectural mismatches. These have been tackled, so far, at the component level, through component adaptation techniques, but they also must be tackled at an architectural level of abstraction. In this paper we propose an approach for resolving architectural mismatches, with the aid of architectural reconciliation. The approach consists of designing and subsequently reconciling two architectural models, one that is forward-engineered from the requirements and another that is reverse-engineered from the COTS-based implementation. The final reconciled model is optimally adapted both to the requirements and to the actual COTS-based implementation. The contribution of this paper lies in the application of architectural reconciliation in the context of COTS-based software development. Architectural modeling is based upon the UML 2.0 standard, while the reconciliation is performed by transforming the two models, with the help of architectural design decisions.
Investigating distributed simulation with COTS simulation packages: Experiences with Simul8 and the HLA
No full textCommercial-off-the-shelf simulation packages (CSPs) are used widely in industry. Several research groups are currently working towards the creation of distributed simulation with these CSPs. The motivations to do this are various and are largely unproven as there are very few good examples of this kind of distributed simulation in practice. Our goal is therefore to create a distributed simulation environment using CSPs that will allow end users to make their own decisions as to whether this technology will be useful. This paper presents continuing research in creating such an environment using the CSP Simul8 and the High Level Architecture, the IEEE 1516 standard for distributed simulation. The scope of this paper is limited to the CSPI-PDG Type I Interoperability Reference Model
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