Analysis of Feature Models Using Alloy: A Survey

Feature Models (FMs) are a mechanism to model variability among a family of closely related software products, i.e. a software product line (SPL). Analysis of FMs using formal methods can reveal defects in the specification such as inconsistencies that cause the product line to have no valid products. A popular framework used in research for FM analysis is Alloy, a light-weight formal modeling notation equipped with an efficient model finder. Several works in the literature have proposed different strategies to encode and analyze FMs using Alloy. However, there is little discussion on the relative merits of each proposal, making it difficult to select the most suitable encoding for a specific analysis need. In this paper, we describe and compare those strategies according to various criteria such as the expressivity of the FM notation or the efficiency of the analysis. This survey is the first comparative study of research targeted towards using Alloy for FM analysis. This review aims to identify all the best practices on the use of Alloy, as a part of a framework for the automated extraction and analysis of rich FMs from natural language requirement specifications.Comment: In Proceedings FMSPLE 2016, arXiv:1603.0857

Time and Energy Managed Operations (TEMO): Cessna Citation II Flight Trials

From 9-26 October 2015 the Netherlands Aerospace Centre (NLR) in cooperation with Delft University of Technology (DUT) has executed Clean Sky flight trials with the Cessna Citation II research aircraft. The trials consisted of several descents and approaches at the Eelde airport near Groningen, demonstrating the TEMO (Time and Energy Managed Operations) concept developed in the Clean Sky Joint Technology Initiative research programme as part of the Systems for Green Operations (SGO) Integrated Technology Demonstrator. A TEMO descent aims to achieve an energy-managed idle-thrust continuous descent operation (CDO) while satisfying ATC time constraints, to maintain runway throughput. An optimal descent plan is calculated with an advanced on-board real-time aircraft trajectory optimisation algorithm considering forecasted weather and aircraft performance. The optimised descent plan was executed using the speed-on-elevator mode of an experimental Fly-By-Wire (FBW) system connected to the pitch servo motor of the Cessna Citation II aircraft. Several TEMO conceptual variants have been flown. It has been demonstrated that the TEMO concept enables arrival with timing errors below 10 seconds. The project was realised with the support of CONCORDE partners Universitat Politècnica de Catalunya (UPC) and PildoLabs from Barcelona, and the Royal Netherlands Meteorological Institute (KNMI).Peer ReviewedPostprint (published version

Flight testing Time and Energy Managed Operations (TEMO)

The expected growth in air traffic combined with an increased public concern for the environment, have forced legislators to rethink the current air traffic system design. The current air traffic system operates at its capacity limits and is expected to lead to increased delays if traffic levels grow even further. Both in the United States and Europe, research projects have been initiated to develop the future Air Transportation System (ATS) to address capacity, and environmental, safety and economic issues. To address the environmental issues during descent and approach, a novel Continuous Descent Operations (CDO) concept, named Time and Energy Managed Operations (TEMO), has been developed co-sponsored by the Clean Sky Joint Undertaking. It uses energy principles to reduce fuel burn, gaseous emissions and noise nuisance whilst maintaining runway capacity. Different from other CDO concepts, TEMO optimizes the descent by using energy management to achieve a continuous engine-idle descent, while satisfying time constraints on both the Initial Approach Fix (IAF) and the runway threshold. As such, TEMO uses timemetering at two control points to facilitate flow management and arrival spacing. TEMO is in line with SESAR step 2 capabilities, since it proposes 4D trajectory management and is aimed at providing significant environmental benefits in the arrival phase without negatively affecting throughput, even in high density and peak-hour operations. In particular, TEMO addresses SESAR operational improvement (OI) TS-103: Controlled Time of Arrival (CTA) through use of datalink [1]. TEMO has been validated starting from initial performance batch studies at Technology Readiness Level (TRL) 3, up to Human-in-the-Loop studies in realistic environments using a moving base flight simulator at TRL 5 ([2]-[6]). In this paper the definition, preparation, performance and analysis of a flight test experiment is described with the objective to demonstrate the ability of the TEMO algorithm to provide accurate and safe aircraft guidance toward the Initial Approach Fix (IAF), and further down to the Stabilization Point (1000 ft AGL), to demonstrate the ability of the TEMO algorithm to meet absolute time requirements at IAF and/or runway threshold and to evaluate the performance of the system under test (e.g. fuel usage).Peer ReviewedPostprint (published version

Leadership conversations: the impact on patient environments

Purpose – The aim of this study is to examine 15 NHS acute trusts in England that achieved high scores at all their hospitals in the first four national Patient Environment audits. No common external explanations were discernible. This paper seeks to examine whether the facilities managers responsible for the Patient Environment displayed a consistent leadership style. Design/methodology/approach – Overall, six of the 15 trusts gave permission for the research to take place and a series of unstructured interviews and observations were arranged with 22 facilities managers in these trusts. Responses were transcribed and categorised through multiple iteration. Findings – The research found common leadership and managerial behaviours, many of which could be identified from other literature. The research also identified managers deliberately devoting energy and time to creating networks of conversations. This creation of networks through managing conversation is behaviour less evident in mainstream leadership literature or in the current Department of Health and NHS leadership models. Practical implications – The findings of this study offer managers (particularly those in FM and managers across NHS) a unique insight into the potential impact of leaders giving an opportunity to re-model thinking on management and leadership and the related managerial development opportunities. It provides the leverage to move facilities management from the role of a commodity or support service, to a position as a true enabler of business. Originality/value – Original research is presented in a previously under-examined area. The paper illuminates how facilities management within trusts achieving high Patient Environment Action Team (PEAT) scores is led.</p

Rolling-sliding laboratory tests of friction modifiers in dry and wet wheel-rail contacts

Friction management has been carried out extensively in the majority of railway networks in the last few years. A popular practice is the application of friction modifiers to increase the adhesion level in contaminated wheel-rail contacts. Two friction modifiers have particularly been used or tested on several railway networks as adhesion enhancers to facilitate the traction and braking operation under poor adhesion conditions. However, for assessment of the performance the railway operators and infrastructure managers mostly rely on practical observations that do not elucidate completely the effectiveness and side effects of these adhesion enhancers. In this paper, the constituents of the two friction modifiers are identified and the solid components are analyzed. A twin-disk roller rig has been used to study their performance in dry and wet contacts under closely controlled laboratory conditions. The adhesion characteristics of both friction modifiers are examined for different slip ratios. Furthermore, the wheel and rail disks are examined after a series of dry tests to analyze the mass loss, the surface damage, the change in surface hardness and roughness, and the subsurface deformation caused by the friction modifiers compared to dry clean contacts. (C) 2009 Elsevier B.V. All rights reserved

Design & development of a simulation model to analyse scheduling rules in an FMS in a virtual manufacturing environment : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Manufacturing and Industrial Technology at Massey University

Due to the rapid changes in the needs of the customer for new products, the future manufacturing systems must cope with these changes. Hence, the need for the manufacturing systems to support these changes in the products with shorter lead times within a single manufacturing facility. The Virtual Manufacturing System (VMS) is one concept which can assist in meeting these demands. The VMS concept enables the manufacturing system designers to emulate and test the performance of the future manufacturing systems. This research has given an overview of the new concepts of Virtual Manufacturing Systems and Virtual Manufacturing in general. A Virtual Reality Software tool has been used to realise the VMS concept. A Virtual Manufacturing Environment representing a Flexible Manufacturing System (FMS) has been modelled. A simulation control language is employed for developing simulation control logics and decision making control logics for the development of the FMS model. The modelled FMS is implemented and tested through simulation experiments. The testing is done by analysing the traditional scheduling rules in a manufacturing facility. Average Machine Utilisation, Mean Flow Time, Average Queue Lengths and the System Production Rate are measured as the System Performance Measures for the evaluation of the scheduling rules. This research has identified that the Virtual Manufacturing Software is a powerful tool which can identify optimum configurations and highlight potential problems before a final and expensive manufacturing system is established physically

BIM and its impact upon project success outcomes from a Facilities Management perspective

The uptake of Building Information Modelling (BIM) has been increasing, but some of its promoted potential benefits have been slow to materialise. In particular, claims that BIM will revolutionise facilities management (FM) creating efficiencies in the whole-life of building operations have yet to be achieved on a wide scale, certainly in comparison to tangible progress made for the prior design and construction phases. To attempt to unravel the factors at play in the adoption of BIM during the operational phase, and in particular, understand if adoption by facilities managers (FMs) is lagging behind other disciplines, this study aims to understand if current BIM processes can ease the challenges in this area faced by facilities management project stakeholders. To do this, success from a facilities management viewpoint is considered and barriers to facilities management success are explored, with focused BIM use proposed as a solution to these barriers. Qualitative research was undertaken, using semi structured interviews to collect data from a non-probability sample of 7 project- and facilities- management practitioners. Key results from this study show that the main barrier to BIM adoption by facilities managers is software interoperability, with reports that facilities management systems are unable to easily import BIM data produced during the design and construction stages. Additionally, facilities managers were not treated as salient stakeholders by Project Managers, further negatively affecting facilities management project success outcomes. A µresistance to change was identified as another barrier, as facilities managers were sceptical of the ability of current BIMenabled systems promoted as being FM compatible to be able to replicate their existing Computer Aided Facility Management (CAFM) legacy software and its user required capabilities. The results of this study highlight that more work is needed to ensure that BIM benefits the end user, as there was no reported use of BIM data for dedicated facilities management purposes. Further investigation into the challenges of interoperability could add significant value to this developing research area.The uptake of Building Information Modelling (BIM) has been increasing, but some of its promoted potential benefits have been slow to materialise. In particular, claims that BIM will revolutionise facilities management (FM) creating efficiencies in the whole-life of building operations have yet to be achieved on a wide scale, certainly in comparison to tangible progress made for the prior design and construction phases. To attempt to unravel the factors at play in the adoption of BIM during the operational phase, and in particular, understand if adoption by facilities managers (FMs) is lagging behind other disciplines, this study aims to understand if current BIM processes can ease the challenges in this area faced by facilities management project stakeholders. To do this, success from a facilities management viewpoint is considered and barriers to facilities management success are explored, with focused BIM use proposed as a solution to these barriers. Qualitative research was undertaken, using semi structured interviews to collect data from a non-probability sample of 7 project- and facilities- management practitioners. Key results from this study show that the main barrier to BIM adoption by facilities managers is software interoperability, with reports that facilities management systems are unable to easily import BIM data produced during the design and construction stages. Additionally, facilities managers were not treated as salient stakeholders by Project Managers, further negatively affecting facilities management project success outcomes. A µresistance to change was identified as another barrier, as facilities managers were sceptical of the ability of current BIMenabled systems promoted as being FM compatible to be able to replicate their existing Computer Aided Facility Management (CAFM) legacy software and its user required capabilities. The results of this study highlight that more work is needed to ensure that BIM benefits the end user, as there was no reported use of BIM data for dedicated facilities management purposes. Further investigation into the challenges of interoperability could add significant value to this developing research area