Relating fair testing and accordance for service replaceability

AbstractThe accordance pre-order describes whether a service can safely be replaced by another service. That is, all partners for the original service should be partners for the new service. Partners for a service interact with the service in such a way that always a certain common goal can be reached.We relate the accordance pre-order to the pre-orders known from the linear–branching time spectrum, notably fair testing. The differences between accordance and fair testing include the modeling of termination and success, and the parts of the services that cannot be used reliably by any partner. Apart from the theoretical results, we address the practical relevance of the introduced concepts

Choices of Contention: Decision Making Factors Leading to the Substitute Method Over In-Kind Repairs and Their Effectiveness at Lyndhurst Estate

Lyndhurst Mansion, located in Tarrytown, New York is a masterpiece of American Gothic Revival architecture designed by Alexander Jackson Davis beginning in 1838. Since its acquisition by the National Trust in 1961, the property has carried out a number of repairs to the mansion and other buildings on the estate in which a substitute material was chosen over an in-kind material. Financial constraints appear to be the driving force behind these decisions. Other factors, durability of materials and preservation philosophy, also played a role. An aim of this thesis is to determine the role these factors played in choosing methods and materials used in these repairs. Another aim is to assess the success of the substitute method compared to in-kind repair. Research conducted in Lyndhurst\u27s archives as well as interviews with current and past employees provided narrative data regarding the decision making process, while assessment of five case studies provided insight into the effectiveness of the decisions. Findings concluded that cost often outweighed the other considerations when choosing a repair method and materials. Substitute materials at Lyndhurst proved overall to be inferior to those of an in-kind replacement. The findings serve as an example of the financial challenges facing many historic sites

A Delphi Study Using Value-Focused Thinking for United States Air Force Mission Dependency Index Values

Recently, the Air Force Civil Engineer Center (AFCEC) identified that the Mission Dependency Index (MDI) had issues with reflecting the criticality of some mission sets. The MDI is a constructed value assigned to assets that reflects the consequence of failure. The primary mission sets having MDI issues were non-flightline assets. The current Air Force MDI metric relies on data collected using the Naval Facilities Engineering Command (NAVFAC) methodology and adapts the data by using facility categorization codes. The result is a method that compares alternatives to each other to develop an individual asset\u27s MDI value. As a corrective measure to this methodology, non-flightline centric mission sets have been allowed to adjust (i.e. increase) their asset MDI values. This modification in MDI values has led to inflation of the metric. To address the issue, this research focuses on how the MDI values should be assigned by examining both public and private methodologies. Leveraging the Delphi technique and Value Focused Thinking (VFT), three models are created to suggest the proper inputs that should be considered when producing the MDI values for the Air Force\u27s assets. The models inputs were interruptability, redundancy, replaceability and the number of missions affected

Undecidability of accordance for open systems with unbounded message queues

We study asynchronously communicating open systems modeled as Petri nets with an interface. An accordance preorder describes when one open system can be safely replaced by another open system without aecting some behavioral property of the overall system. Although accordance is decidable for several behavioral properties if we assume a previously known bound on the maximal number of pending messages, we show that it is not decidable without this assumption. Keywords: Petri nets, open nets, accordance preorder, theory of computatio

Soundness-preserving refinements of service compositions

Soundness is one of the well-studied properties of processes; it denotes that a final state can be reached from every state that is reachable from the initial state. Soundness-preserving refinements are important for enabling the compositional design of systems. In this paper we concentrate on refinements of service compositions. We model service compositions using Petri nets, and consider specific pairs of places that belong to different services. Starting from a sound service composition, we show how to check whether such a pair of places can be refined by another sound service composition, so that soundness is preserved through the refinement

Fair Subtyping for Multi-Party Session Types

The subtyping relation defined for dyadic session type theories may compromise the liveness of multi-party sessions. In this paper we define a fair subtyping relation for multi-party session types that preserves liveness, we relate it with the subtyping relation for dyadic session types, and we provide coinductive, axiomatic, and algorithmic characterizations for it

Project Selection in Facility and Infrastructure Maintenance Organizations

The current Air Force Civil Engineer Center (AFCEC) built infrastructure Facility Sustainment Restoration and Modernization (FSRM) portfolio management methodology results in an unbalanced project portfolio. The consequence of this unbalance is that majority of the funding goes towards buildings on the flightline and Facility Support Services activities do not get adequate funding which leads to further deterioration of those facilities. This research investigates whether decision support framework based on Value-Focused Thinking (VFT) process yields better project selection outcomes for facility and infrastructure maintenance organizations. To accomplish that, the investigation focuses on understanding current AFCEC decision support methodology, building an alternative one based on VFT process, and then applying the result to a sampling of projects. Findings of the investigation prove that the VFT process yields a decision support framework that successfully balances FSRM project portfolio by ranking the projects based on their level of contribution to decision-maker’s values affecting facility and infrastructure maintenance organizations

Pass-through of unfair trading practices in EU food supply chains

This report presents the results of the research project “Pass-Through of Unfair Trading Practices in EU Food Supply Chains: Methodology and Empirical Application”. The purpose of the project is to design and test a monitoring system of unfair trading practices (UTP) along the agri-food supply chain. The investigation has special focus on assessment of the “pass-through effect”, defined as the consequences for the entire supply chain of UTPs adopted in a specific transaction. The report includes: (i) a review of the economic literature for a better understanding of the economic principles of UTPs; (ii) a review of available data sources and past experiences in UTP monitoring; (iii) the illustration of two alternative approaches for UTP monitoring: B-SEA (broad-scope empirical analysis) and IDEA (in-depth analysis); (iv) a test application of the two approaches to the EU fresh fruit sector; (v) a comparative analysis of the IDEA and B-SEA results and (vi) a discussion of the implications of our research.JRC.D.4-Economics of Agricultur