Integrating heterogeneous distributed COTS discrete-event simulation packages: An emerging standards-based approach

This 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

A Methodology for Engineering Collaborative and ad-hoc Mobile Applications using SyD Middleware

Today’s web applications are more collaborative and utilize standard and ubiquitous Internet protocols. We have earlier developed System on Mobile Devices (SyD) middleware to rapidly develop and deploy collaborative applications over heterogeneous and possibly mobile devices hosting web objects. In this paper, we present the software engineering methodology for developing SyD-enabled web applications and illustrate it through a case study on two representative applications: (i) a calendar of meeting application, which is a collaborative application and (ii) a travel application which is an ad-hoc collaborative application. SyD-enabled web objects allow us to create a collaborative application rapidly with limited coding effort. In this case study, the modular software architecture allowed us to hide the inherent heterogeneity among devices, data stores, and networks by presenting a uniform and persistent object view of mobile objects interacting through XML/SOAP requests and responses. The performance results we obtained show that the application scales well as we increase the group size and adapts well within the constraints of mobile devices

Towards a choreography for IRS-III

In this paper we describe our ongoing work in developing a choreog-raphy for IRS-III. IRS-III is a framework and platform for developing WSMO based semantic web services. Our choreography framework is based on the KADS system-user co-operation model and distinguishes between the direction of messages within a conversation and which actor has the initiative. The im-plementation of the framework is based on message pattern handlers which are triggered whenever an incoming message satisfies pre-defined constraints. Our framework is explained through an extensive example

Agent-Based Model of Price Competition and Product Differentiation on Congested Networks

Using consistent agent-based techniques, this research models the decision-making processes of users and infrastructure owner/operators to explore the welfare consequence of price competition, capacity choice, and product differentiation on congested transportation networks. Component models include: (1) An agent-based travel demand model wherein each traveler has learning capabilities and unique characteristics (e.g. value of time); (2) Econometric facility provision cost models; and (3) Representations of road authorities making pricing and capacity decisions. Different from small-network equilibrium models in prior literature, this agent-based model is applicable to pricing and investment analyses on large complex networks. The subsequent economic analysis focuses on the source, evolution, measurement, and impact of product differentiation with heterogeneous users on a mixed ownership network (with tolled and untolled roads). Two types of product differentiation in the presence of toll roads, path differentiation and space differentiation, are defined and measured for a base case and several variants with different types of price and capacity competition and with various degrees of user heterogeneity. The findings favor a fixed-rate road pricing policy compared to complete pricing freedom on toll roads. It is also shown that the relationship between net social benefit and user heterogeneity is not monotonic on a complex network with toll roads.Network dynamics, road pricing, autonomous links, privatization, price competition, product differentiation, agent-based transportation model

An urban general equilibrium model with multiple household structures and travel mode choice

Households in real cities are heterogeneous regarding their size and composition. An aspect usually neglected in urban models used to study economic and policy issues that arise in today's cities. We develop an urban general equilibrium model that takes a more complex household structure explicitly into account. The model is based on the single consumer type model of Anas and Xu (1999) or Anas and Rhee (2006) and treats the interactions of urban product, labor and land markets as well as linkages between city firms and different consumer types living in different household structures. Households differ not only in endowments, preferences and their valuation in regard to different travel modes, but also in size and the composition regarding their members. The implementation of a more complex household structure then allows studying a broad range of further urban economic issues, which treat different household structures differently. --Urban Economics,General Equilibrium,Household structure,Location choice

Temporary Clusters and Knowledge Creation: The Case of Tourism@

With respect to the knowledge-based-view and management science, innovations contribute to a company's competitiveness. And for successful innovation process, companies need to share, create and combine their internal knowledge as well as managing their external relationships and opportunities. Consequently, it is widely accepted that clusters - systemic and local configurations - by supporting horizontal and vertical knowledge exchange could be a fundamental mean for innovation. However, the prolific literature on clusters analyse them only as durable and permanent entities. Yet, interestingly, some forms of temporary organizations as trade fairs, conventions and other professional gatherings, are similar to permanent clusters, but in a temporary, repeated and intensified form. Maskell, Bathelt and Malmberg (2004) even call them “temporary cluster” using the concept to define a short-lived hotspot of intense knowledge exchange, network building and idea generation. It gathers heterogeneous participants in the same spot enabling them to bring together their specific knowledge through intensive interactions. Nevertheless, to date, we observed that the literature focusing on temporary clusters is limited. Notwithstanding, it requires growing attention for management science. In fact, the literature existing on temporary clusters, had asserted that these transient events are important for companies to access markets and knowledge pools in different part of the world. Therefore we consider temporary clusters as a significant vector for the building of trans-local business relations in common situations of incomplete knowledge and uncertainty. Besides, temporary clusters help developing global knowledge pipelines to benefit from outside knowledge.In this context, the paper will analyze a specific empirical case of temporary organization related to the tourism industry. Two arguments support this choice. On the one hand, as stated by Maskell et al. (2005), ‘identifying, selecting, approaching and interacting with new partners is a tricky and costly process' and, we think, even more in the tourism industry. Indeed, the tourism industry is structured by dispersed activities in nature, time and space that need to be combined and assembled dynamically. On the other hand, the tourism industry has been one of the most innovative activities related to the development of ICT, almost 50% of the innovations in the e-commerce activity come from e-tourism or m-tourism. Therefore, the analysis of a temporary cluster dedicated to this ‘dispersed' activity is particularly relevant.The paper will thus focus on such an event called Tourism@. This major event gathers the main actors of e-tourism and is dedicated to the usages of ICT in the tourism industry. It appears as a unique international trade fair in Europe dedicated to start up innovative companies, high tech SMEs, academic research, as well as large multinationals. Tourism@' specificity lies in the fact that each year, since 2001, the event includes the organization of a competition rewarding projects for their creativity and commitment in developing and implementing either new technologies or new uses for the tourism industry. The projects involved in this competition (175 since 2001) will be the basic elements of the temporal database we have build, in which the nature of the projects is extensively described (nature of the firm, of the technology, of the team, capabilities implemented, level of innovation...). In order to analyze the evolution of innovative activities in e-tourism, the initial step will be to characterize the projects through three main features: the market they address, nature of the technology and their innovative intensity. The study reveals that, each year, a main technology or a main innovation in terms of uses emerges showing some kind of self organization. Then, two points of the case study will be examined: first, the evolution of the dominant technology over time, and secondly, the diffusion of the emerging technology. Therefrom, the empirical study will aim at analyzing if temporary proximity allows the different actors from tourism industry to set up or mobilize knowledge and social links without requiring durable co-location. Furthermore, it will aim at identifying if, in a dynamic context of annual event, the repeated face to face temporary relations can result in trust and durable cooperation between different organizations. It might be expected that Tourism@ trade fair, in the role of a temporary cluster, enables to develop or implement innovative solutions, supports technology transfers and backs the creation of new markets as well as the fostering of horizontal and vertical relations between stakeholders.The paper is structured as follows. First section will investigate the theory field of temporary clusters and question in what extent a temporary cluster can be considered as a specific temporary organization regarding the interactions it support that lead to knowledge creation. Section two will present the Tourism@ case study; the methodology used and will develop the statistical analysis of the database. Lastly, the third section will be dedicated to the discussion of temporary clusters as a specific form of inter-firm organization that allows intensive exchange of knowledge.Knowledge creation; Temporary cluster; Tourism; Technological innovation

Agents and Brokers as Intermediaries: Their Regulation in Germany

Most markets are characterized by imperfections, mostly market power and limited information. Under these circumstances, intermediaries like real estate agents and insurance brokers play an important role in the economy by facilitating exchange between third parties. As specialized entities they can transmit information, thereby lessening information asymmetries between market participants and can thus enhance the functioning of markets. This special role allows for opportunistic behavior by intermediaries, though. As long as the parties can write enforceable contracts that cover the relevant aspects of the intermediaries behavior, legal regulation is not necessary. In this paper it will be shown, though, that contracts are only partially able to solve possible principalagent problems and that the current legal rules in Germany are inefficient as they can not sufficiently control possible opportunistic behavior. A system of legal rules for intermediaries is sketched, taking into account that severe informa-tional asymmetry is more likely to arise if transactions are infrequent and learning does not take place.