A survey of simulation techniques in commerce and defence

Despite the developments in Modelling and Simulation (M&S) tools and techniques over the past years, there has been a gap in the M&S research and practice in healthcare on developing a toolkit to assist the modellers and simulation practitioners with selecting an appropriate set of techniques. This study is a preliminary step towards this goal. This paper presents some results from a systematic literature survey on applications of M&S in the commerce and defence domains that could inspire some improvements in the healthcare. Interim results show that in the commercial sector Discrete-Event Simulation (DES) has been the most widely used technique with System Dynamics (SD) in second place. However in the defence sector, SD has gained relatively more attention. SD has been found quite useful for qualitative and soft factors analysis. From both the surveys it becomes clear that there is a growing trend towards using hybrid M&S approaches

Is photovoltaic power a cost-effective energy solution for rural peoples in western Sudan?

Sudan like most poor countries suffers from a deficiency in the supply of electrical power, especially for rural areas. Less than 10% of the total population, can benefit from the national grid connection. The paper evaluates the economic, environmental and social issues associated with electrification in western Sudan for rural and nomadic peoples, by assessing three different systems for off-grid electricity supply; stand alone systems powered by diesel generator (gen-set), photovoltaic cells, and a larger distributed generator system (mini-grid). The study indicates that, although photovoltaic might be the best source of electricity from an environmental and social view, unfortunately it currently cannot compete economically. The research identified that Sudanese customs and tax policy adds a significant cost to PV, making diesel generators the best power choice for rural and nomadic regions in Sudan. Other important factors include fuel supply problems and availability of spare parts for generators

Distributed photovoltaic systems: Utility interface issues and their present status. Intermediate/three-phase systems

The interface issues between the intermediate-size Power Conditioning Subsystem (PCS) and the utility are considered. A literature review yielded facts about the status of identified issues

A Conceptual Framework of Reverse Logistics Impact on Firm Performance

This study aims to examine the reverse logistics factors that impact upon firm performance. We review reverse logistics factors under three research streams: (a) resource-based view of the firm, including: Firm strategy, Operations management, and Customer loyalty (b) relational theory, including: Supply chain efficiency, Supply chain collaboration, and institutional theory, including: Government support and Cultural alignment. We measured firm performance with 5 measures: profitability, cost, innovativeness, perceived competitive advantage, and perceived customer satisfaction. We discuss implications for research, policy and practice

Distributed photovoltaic systems: Utility interface issues and their present status

Major technical issues involving the integration of distributed photovoltaics (PV) into electric utility systems are defined and their impacts are described quantitatively. An extensive literature search, interviews, and analysis yielded information about the work in progress and highlighted problem areas in which additional work and research are needed. The findings from the literature search were used to determine whether satisfactory solutions to the problems exist or whether satisfactory approaches to a solution are underway. It was discovered that very few standards, specifications, or guidelines currently exist that will aid industry in integrating PV into the utility system. Specific areas of concern identified are: (1) protection, (2) stability, (3) system unbalance, (4) voltage regulation and reactive power requirements, (5) harmonics, (6) utility operations, (7) safety, (8) metering, and (9) distribution system planning and design

Negotiating the 'trading zone'. Creating a shared information infrastructure in the Dutch public safety sector

Our main concern in this article is whether nation-wide information technology (IT) infrastructures or systems in emergency response and disaster management are the solution to the communication problems the safety sector suffers from. It has been argued that implementing nation-wide IT systems will help to create shared cognition and situational awareness among relief workers. We put this claim to the test by presenting a case study on the introduction of ‘netcentric work’, an IT system-based platform aiming at the creation of situational awareness for professionals in the safety sector in the Netherlands. The outcome of our research is that the negotiation with relevant stakeholders by the Dutch government has lead to the emergence of several fragmented IT systems. It becomes clear that a top-down implementation strategy for a single nation-wide information system will fail because of the fragmentation of the Dutch safety sector it is supposed to be a solution to. As the US safety sector is at least as fragmented as its Dutch counterpart, this may serve as a caveat for the introduction of similar IT systems in the US

Landslide risk management through spatial analysis and stochastic prediction for territorial resilience evaluation

Natural materials, such as soils, are influenced by many factors acting during their formative and evolutionary process: atmospheric agents, erosion and transport phenomena, sedimentation conditions that give soil properties a non-reducible randomness by using sophisticated survey techniques and technologies. This character is reflected not only in spatial variability of properties which differs from point to point, but also in multivariate correlation as a function of reciprocal distance. Cognitive enrichment, offered by the response of soils associated with their intrinsic spatial variability, implies an increase in the evaluative capacity of the contributing causes and potential effects in failure phenomena. Stability analysis of natural slopes is well suited to stochastic treatment of uncertainty which characterized landslide risk. In particular, this study has been applied through a back- analysis procedure to a slope located in Southern Italy that was subject to repeated phenomena of hydrogeological instability (extended for several kilometres in recent years). The back-analysis has been carried out by applying spatial analysis to the controlling factors as well as quantifying the hydrogeological hazard through unbiased estimators. A natural phenomenon, defined as stochastic process characterized by mutually interacting spatial variables, has led to identify the most critical areas, giving reliability to the scenarios and improving the forecasting content. Moreover, the phenomenological characterization allows the optimization of the risk levels to the wide territory involved, supporting decision-making process for intervention priorities as well as the effective allocation of the available resources in social, environmental and economic contexts

Industrial structural geology : principles, techniques and integration : an introduction

The authors wish to acknowledge the generous financial support provided in association with this volume to the Geological Society and the Petroleum Group by Badley Geoscience Ltd, BP, CGG Robertson, Dana Petroleum Ltd, Getech Group plc, Maersk Oil North Sea UK Ltd, Midland Valley Exploration Ltd, Rock Deformation Research (Schlumberger) and Borehole Image & Core Specialists (Wildcat Geoscience, Walker Geoscience and Prolog Geoscience). We would like to thank the fine team at the Geological Society’s Publishing House for the excellent support and encouragement that they have provided to the editors and authors of this Special Publication.Peer reviewedPublisher PD

BOF4WSS : a business-oriented framework for enhancing web services security for e-business

When considering Web services' (WS) use for online business-to-business (B2B) collaboration between companies, security is a complicated and very topical issue. This is especially true with regard to reaching a level of security beyond the technological layer, that is supported and trusted by all businesses involved. With appreciation of this fact, our research draws from established development methodologies to develop a new, business-oriented framework (BOF4WSS) to guide e-businesses in defining, and achieving agreed security levels across these collaborating enterprises. The approach envisioned is such that it can be used by businesses-in a joint manner-to manage the comprehensive concern that security in the WS environment has become