DEVS-based intelligent control of space adapted fluid mixing

The development is described of event-based intelligent control system for a space-adapted mixing process by employing the DEVS (Discrete Event System Specification) formalism. In this control paradigm, the controller expects to receive confirming sensor responses to its control commands within definite time windows determined by its DEVS model of the system under control. The DEVS-based intelligent control paradigm was applied in a space-adapted mixing system capable of supporting the laboratory automation aboard a Space Station

Design of a simulation environment for laboratory management by robot organizations

This paper describes the basic concepts needed for a simulation environment capable of supporting the design of robot organizations for managing chemical, or similar, laboratories on the planned U.S. Space Station. The environment should facilitate a thorough study of the problems to be encountered in assigning the responsibility of managing a non-life-critical, but mission valuable, process to an organized group of robots. In the first phase of the work, we seek to employ the simulation environment to develop robot cognitive systems and strategies for effective multi-robot management of chemical experiments. Later phases will explore human-robot interaction and development of robot autonomy

Coping with Poorly Understood Domains: the Example of Internet Trust

The notion of trust, as required for secure operations over the Internet, is important for ascertaining the source of received messages. How can we measure the degree of trust in authenticating the source? Knowledge in the domain is not established, so knowledge engineering becomes knowledge generation rather than mere acquisition. Special techniques are required, and special features of KBS software become more important than in conventional domains. This paper generalizes from experience with Internet trust to discuss some techniques and software features that are important for poorly understood domains

Kanban devs modelling, simulation and verification

Kanban Control Systems (KCS) have become a widely accepted form of inventory and production control. The creation of realistic Discrete Events Simulation (DES) models of KCS require specification of both information and material flow. There are several commercially available simulation packages that are able to model these systems although the use of an application specific modelling language provides means for rapid model development. A new Kanban specific simulation language as well as a high-speed execution engine is verified in this paper through the simulation of a single stage single part type production line. A single stage single part KCS is modelled with exhaustive enumeration of the decision variables of container sizes and number of Kanbans. Several performance measures were used; 95% Confidence Interval (CI) of container Flow Time (FT), mean line throughput as well as the Coefficient of Variance (CV) of FT and Cycle Time were used to determine the robustness of the control system.<br /

Foundations of Modelling and Simulation of Complex Systems

Modelling and simulation are becoming increasingly important enablers for the analysis and design of complex systems. In application domains such as automotive design, the notion of a "virtual experiment" is taken to the limit and complex designs are model-checked, simulated, and optimized extensively before a single realization is ever made. This "doing it right the first time" leads to tremendous cost savings and improved quality. Furthermore, with appropriate models, it is often possible to automatically synthesize (parts of) the system-to-be-built. In this paper, the basic concepts of modelling and simulation are introduced. These concepts are based on general systems theory and start from the idea of a model as an abstract representation of knowledge about structure and behaviour of some system. The purpose is either analysis or design in a particular experimental context. Typically, different formalisms are used such as Ordinary Differential Equations, Queueing Networks, and State Automata. It will be shown how these different formalisms all share a common structure and differ in the choice of time base, state space, and description of temporal evolution. This allows one to classify formalisms on the one hand and to find a common ground for implementing simulators on the other hand

A Modeling and Verification Approach to the Design of Distributed IMA Architectures Using TTEthernet

AbstractIntegrated Modular Avionics (IMA) architectures complemented with Time-Triggered Ethernet (TTEthernet) provides a strong platform to support the design and deployment of distributed avionic software systems. The complexity of the design and continuous integration of such systems can be managed using a model-based methodology. In this paper, we build on top of our extension of the AADL modeling language to model TTEthernet-based distributed systems and leverage model transformations to enable undertaking the verification of the system models produced with this methodology. In particular, we propose to transform the system models to a model suitable for a simulation with DEVS. We illustrate the proposed approach using an example of a navigation and guidance system and we use this example to show the verification of the contention-freedom property of TTEthernet schedule

Dependence and trust between suppliers and industrial customers

Suppliers have experienced unexpected consequences for their businesses due to changing situations for their important customers. Such events may also occur at short notice, at least when it comes to necessary and radical decisions. Often suppliers are not aware of the full extent of these events until it is too late for them to take countermeasures, i.e. develop appropriate strategies. With increasing turbulence in the marketplace, it is clear that firms need to be aware of relationship-oriented marketing strategies. To cope with change the supplier and its customer will need strategies based on jointly understood action. Action, both strategic and operational, is based on each party’s meanings concerning why they do business with one another (enactment). Dependence and trust between the parties are issues in their construction of meaning and will therefore underlie their enactment. The purpose of this paper is to investigate dependence and trust between suppliers and industrial customers, implications for action of dependence and trust, and, finally, draw conclusions about dependence and trust for business strategy. Dependence. A firm can be dependent on a specific other firm due to investments in specific assets geared to that firm. A literature survey identifies five types of specific assets: Personal relations, competence, integration of governance systems, dedicated volume of goods/services, and product/process specialization. Another reason for dependence is the structure of the market, which may lack alternative providers of similar products. Then it becomes difficult or impossible due to large switching costs to substitute one firm with another for the provision of good/services. Trust. A literature survey concerning trust leads to the conclusion that important aspects of trust probably vary between different environments and settings where trust is an issue. Since trust between suppliers and industrial customers is the issue in this study, the notion and implications of trust among strategic decision-makers in that empirical setting would be important. By using the trust literature together with an empirical investigation three types of trust for the study are discerned: Relationship-based, competence-based and moral based trust. Dependence and trust. There is a temporal interplay between trust and dependence. Trust is expectation concerning the future. Dependence differs from trust by being formed in the present time and may therefore become a means to avoid the problems in assessing the future. But when you choose to trust someone, as a consequence you become dependent. Interrelationship between dependence and trust is thus complex and intertwined. It varies with task, situation and persons involved. The order of events in time has an impact. Earlier actions by actors influence later ones. Trust develops stepwise in repeated encounters between the parties. The parties’ actions towards each other and the evolvement of action processes seem to be the key to understanding suppliers’ and customers’ dependence and trust. This interplay is in the paper illustrated with dependence and trust development in two dyads of supplier – industrial customer. In the cases we could discern that meaning construction with dependence and trust, interrelated with action, can lead to improved or deteriorated business relations between the parties. As in the cases patterns of virtuous circles or vicious circles may emerge. Expectations concerning the other party, i.e. trust, could thus change substantially, leading to different types of action than before. Conclusions concerning business strategy. Dependence and trust have different impacts on a firm’s strategy and consequently on strategic change. Dependence indicates preconditions for action and what action is precluded due to the characteristics of business between the parties in terms of specific assets and substitutability. In all, dependence sets limits for strategy, wide or narrow. Trust, on the other hand, can be a driving force shaping strategy, opening up possibilities in markets and products as well as governance systems linking parties. But lack of trust and deteriorating trust may also preclude business that could otherwise have been done. There needs to be trust backing up any viable strategy and strategic change. Furthermore, it is vital that the parties concerned convey in their communication what they consider to be meanings in their business. If they have dissimilar views on dependence, action may become disjointed and not understood by the other party. Likewise, openness concerning trust in one another is needed in order to display mutuality in trust or build mutual trust. On industry level trust in supplier relationships at firm level can be promoted by providing information exchange and arenas for that purpose to support potential business partners to embark upon trust development. Society, in its policy-making, can promote trust on firm level by clear-cut rules of the game, which – among other things – will reduce the risks that parties in an exchange will go to disjointed action due to different interpretations of what society requires from firms in business.supply chain; strategy; business relationship

Co-production on the Edge of Project and Process Management - The Sijtwende development project

The goal of this paper is to describe and analyze co-production in public private partnerships in spatial planning. We will describe one specific case study, the location development project Sijtwende on the edge of two municipalities (The Hague and Voorburg), on the edge of public and private investments and on the edge of urban development and extension of the mobility system. We will elaborate the bottlenecks in the cooperation between several actors involved. Furthermore we will look for important breakthroughs in the process of collaborative development of the area. How was it possible that after a public lock in situation that took more than twenty years a private party was able to force a breakthrough? Finally we will deal with the question what this case learns us for the management of these complex processes of co-production. We will combine theoretical thoughts and empirical insights from our in-depth case study in order to find balances in using project management and process management strategies for managing complex spatial planning processes.

SES and Ecore for Ontology-based Scenario Modeling in Aviation Scenario Definition Language (ASDL)

The Aviation Scenario Definition Language (ASDL) is a domain-specific language proposal which aims to provide a standard aviation scenario specification mechanism and enable the reuse of scenario generation methods among different simulators. This paper presents a model-based scenario development approach that exploits Eclipse Modeling Framework (EMF) core (Ecore) and System Entity Structure (SES) for metamodeling and modeling these elements. The construction of the ASDL metamodel using both platforms is described to illustrate the processes. As a result of comparing two approaches, it is concluded that they follow a similar structure in the hierarchical definition of modeled elements despite there being different toolsets available in each method. Thereby, each metamodel can be easily converted into the other type using transformations. As an application use case, the use of the proposed ontology-based scenario development in the aviation domain is discussed, where a training tool is being developed that utilizes SES/Ecore approach to build a scenario-driven training tool for air traffic controllers