Model Checking and Model-Based Testing : Improving Their Feasibility by Lazy Techniques, Parallelization, and Other Optimizations

This thesis focuses on the lightweight formal method of model-based testing for checking safety properties, and derives a new and more feasible approach. For liveness properties, dynamic testing is impossible, so feasibility is increased by specializing on an important class of properties, livelock freedom, and deriving a more feasible model checking algorithm for it. All mentioned improvements are substantiated by experiments

Working Notes from the 1992 AAAI Spring Symposium on Practical Approaches to Scheduling and Planning

The symposium presented issues involved in the development of scheduling systems that can deal with resource and time limitations. To qualify, a system must be implemented and tested to some degree on non-trivial problems (ideally, on real-world problems). However, a system need not be fully deployed to qualify. Systems that schedule actions in terms of metric time constraints typically represent and reason about an external numeric clock or calendar and can be contrasted with those systems that represent time purely symbolically. The following topics are discussed: integrating planning and scheduling; integrating symbolic goals and numerical utilities; managing uncertainty; incremental rescheduling; managing limited computation time; anytime scheduling and planning algorithms, systems; dependency analysis and schedule reuse; management of schedule and plan execution; and incorporation of discrete event techniques

Proceedings of the 2nd Conference on Production Systems and Logistics (CPSL 2021)

Proceedings of the CPSL 202

Supporting user appropriation of public displays

Despite their prevalence, public engagement with pervasive public displays is typically very low. One method for increasing the relevance of displayed content (and therefore hopefully improving engagement) is to allow the viewer themselves to affect the content shown on displays they encounter – for example, personalising an existing news feed or invoking a specific application on a display of their choosing. We describe this process as viewer appropriation of public displays. This thesis aims to provide the foundations for appropriation support in future ‘open’ pervasive display networks. Our architecture combines three components: Yarely, a scheduler and media player; Tacita, a system for allowing users to make privacy-preserving appropriation requests, and Mercury, an application store for distributing content. Interface points between components support integration with thirdparty systems; a prime example is the provision of Content Descriptor Sets (CDSs) to describe the media items and constraints that determine what is played at each display. Our evaluation of the architecture is both quantitive and qualitative and includes a mixture of user studies, surveys, focus groups, performance measurements and reflections. Overall we show that it is feasible to construct a robust open pervasive display network that supports viewer appropriation. In particular, we show that Yarely’s thick-client approach enables the development of a signage system that provides continuous operation even in periods of network disconnection yet is able to respond to viewer appropriation requests. Furthermore, we show that CDSs can be used as an effective means of information exchange in an open architecture. Performance measures indicate that demanding personalisation scenarios can be satisfied, and our qualitative work indicates that both display owners and viewers are positive about the introduction of appropriation into future pervasive display systems

Two-phased Engineer-to-order Model as Competitive Advantage

The aim of this research is to find out how change orders and their negative effects can be reduced by using a two-phased Engineer-to-Order (ETO) model and other strategies. An in-depth single case study method is used to achieve this objective by relying on both qualitative and quantitative data in order to observe change order dilemma and give valuable suggestions for the case company. Change order dilemma forces manufacturers to accept change orders even though their negative effects are higher than what can be charged from the customer. However, refusing to accept changes can cause other issues, such as negative customer experience and lost sales. The case company manufactures induction machines and operates in the low-volume ETO sector where profits are low, competition is intense and product lead times are between 12 and 28 weeks. The literature review focuses on change order dilemma by reviewing the constituents of change order occurrence and ways of mitigating change orders and their negative effects. Moreover, the principles of ETO supply chains, common manufacturing issues in the ETO sector and possible strategies for gaining competitive advantage are reviewed. The research concludes that change order occurrence is high in challenging product groups which include numerous special components. In addition, certain countries, customers and industry specifications increase the likelihood of changes. The negative effects of change orders disturb the order-delivery process and cause additional and hidden costs that are not possible to charge from the customer afterwards. A scenario analysis reveals that the total value of change orders can amount to more than one percent of the annual revenue of the case company. Findings suggest that both the two-phased ETO model and other strategies, such as increasing transparency between critical stakeholders and enhancing the current change order management practices, are required to overcome change order dilemma and enhance the efficiency of ETO supply chains. The two-phased ETO model helps reduce the number of change orders and mitigate negative effects of change orders. An implementation plan for the two-phased ETO model is developed to increase its usage and clarify criteria and internal instructions to use it for the right projects