CAN CHANGE PREDICTION HELP PRIORITISE REDESIGN WORK IN FUTURE ENGINEERING SYSTEMS?

Future design environments will necessitate improved management of the propagation and impacts of changes. To ascertain whether change prediction can assist in making better work prioritisation decisions, this paper develops a new simulation approach and applies it to a model of a complex aerospace product, which was elicited from industry. We use an accepted technique to generate potential change propagation trees and apply Monte Carlo methods to generate a sample space within which multiple scheduling policies could be evaluated and compared. The experiments reveal that poor coordination of change activity can result in significant process inefficiencies, that the potential for inefficiency increases for larger change networks, and that a modest ability to accurately predict change propagation in the specific case at hand could have a dramatic effect in reducing unnecessary rework. The experiments also suggest that the capability of predicting multiple steps of change propagation would provide only minimal additional improvement.International Design Conference - DESIGN 201

A 5D Building Information Model (BIM) for Potential Cost-Benefit Housing: A Case of Kingdom of Saudi Arabia (KSA)

The Saudi construction industry is going through a process of acclimatizing to a shifting fiscal environment. Due to recent fluctuations in oil prices, the Saudi construction sector decided to adjust to current trade-market demands and rigorous constitutional regulations because of competitive pressures. This quantitative study assesses and compares existing flat design vs. mid-terrace housing through cost estimation and design criteria that takes family privacy into consideration and meets the needs of Saudi Arabian families (on average consisting of seven members). Five pilot surveys were undertaken to evaluate the property preference type of Saudi families. However, Existing models did not satisfy the medium range family needs and accordingly a 5D (3D + Time + Cost) Building Information Modelling (BIM) is proposed for cost benefiting houses. Research results revealed that mid-terrace housing was the best option, as it reduced land usage and construction costs. While, 5D BIM led to estimate accurate Bill of Quantities (BOQ) and the appraisal of construction cost

A Taxonomy of Data Grids for Distributed Data Sharing, Management and Processing

Data Grids have been adopted as the platform for scientific communities that need to share, access, transport, process and manage large data collections distributed worldwide. They combine high-end computing technologies with high-performance networking and wide-area storage management techniques. In this paper, we discuss the key concepts behind Data Grids and compare them with other data sharing and distribution paradigms such as content delivery networks, peer-to-peer networks and distributed databases. We then provide comprehensive taxonomies that cover various aspects of architecture, data transportation, data replication and resource allocation and scheduling. Finally, we map the proposed taxonomy to various Data Grid systems not only to validate the taxonomy but also to identify areas for future exploration. Through this taxonomy, we aim to categorise existing systems to better understand their goals and their methodology. This would help evaluate their applicability for solving similar problems. This taxonomy also provides a "gap analysis" of this area through which researchers can potentially identify new issues for investigation. Finally, we hope that the proposed taxonomy and mapping also helps to provide an easy way for new practitioners to understand this complex area of research.Comment: 46 pages, 16 figures, Technical Repor

The 1990 progress report and future plans

This document describes the progress and plans of the Artificial Intelligence Research Branch (RIA) at ARC in 1990. Activities span a range from basic scientific research to engineering development and to fielded NASA applications, particularly those applications that are enabled by basic research carried out at RIA. Work is conducted in-house and through collaborative partners in academia and industry. Our major focus is on a limited number of research themes with a dual commitment to technical excellence and proven applicability to NASA short, medium, and long-term problems. RIA acts as the Agency's lead organization for research aspects of artificial intelligence, working closely with a second research laboratory at JPL and AI applications groups at all NASA centers

Validate implementation correctness using simulation: the TASTE approach

High-integrity systems operate in hostile environment and must guarantee a continuous operational state, even if unexpected events happen. In addition, these systems have stringent requirements that must be validated and correctly translated from high-level specifications down to code. All these constraints make the overall development process more time-consuming. This becomes especially complex because the number of system functions keeps increasing over the years. As a result, engineers must validate system implementation and check that its execution conforms to the specifications. To do so, a traditional approach consists in a manual instrumentation of the implementation code to trace system activity while operating. However, this might be error-prone because modifications are not automatic and still made manually. Furthermore, such modifications may have an impact on the actual behavior of the system. In this paper, we present an approach to validate a system implementation by comparing execution against simulation. In that purpose, we adapt TASTE, a set of tools that eases system development by automating each step as much as possible. In particular, TASTE automates system implementation from functional (system functions description with their properties – period, deadline, priority, etc.) and deployment(processors, buses, devices to be used) models. We tailored this tool-chain to create traces during system execution. Generated output shows activation time of each task, usage of communication ports (size of the queues, instant of events pushed/pulled, etc.) and other relevant execution metrics to be monitored. As a consequence, system engineers can check implementation correctness by comparing simulation and execution metrics

An integrated approach for requirement selection and scheduling in software release planning

It is essential for product software companies to decide which requirements should be included in the next release and to make an appropriate time plan of the development project. Compared to the extensive research done on requirement selection, very little research has been performed on time scheduling. In this paper, we introduce two integer linear programming models that integrate time scheduling into software release planning. Given the resource and precedence constraints, our first model provides a schedule for developing the requirements such that the project duration is minimized. Our second model combines requirement selection and scheduling, so that it not only maximizes revenues but also simultaneously calculates an on-time-delivery project schedule. Since requirement dependencies are essential for scheduling the development process, we present a more detailed analysis of these dependencies. Furthermore, we present two mechanisms that facilitate dynamic adaptation for over-estimation or under-estimation of revenues or processing time, one of which includes the Scrum methodology. Finally, several simulations based on real-life data are performed. The results of these simulations indicate that requirement dependency can significantly influence the requirement selection and the corresponding project plan. Moreover, the model for combined requirement selection and scheduling outperforms the sequential selection and scheduling approach in terms of efficiency and on-time delivery. \u

Organizational alternatives for flexible manufacturing systems

There is an increasing importance of different productive architectures related to worker involvement in the decision making, where is given due attention to the intuitive capabilities and the human knowledge in the optimization and flexibilization of manufacturing processes. Thus having reference point architecture of a flexible manufacturing and assembling system existent at UNINOVA-CRI, we will present some exploratory hypothesis about applicability of the concept of hybridization and its repercussions on the definition of jobs, in those organizations and in the formation of working teams.flexibility; robotics; work organization; manufacturing industry