QoS guarantee with adaptive transmit power and message rate control for DSRC vehicle network based road safety applications

Quality of services (QoS) support is critical for dedicated short range communications (DSRC) vehicle networks based collaborative road safety applications. In this paper we propose an adaptive power and message rate control method for DSRC vehicle networks at road intersections. The design objective is to provide high availability and low latency channels for high priority emergency safety applications while maximizing channel utilization for low priority routine safety applications. In this method an offline simulation based approach is used to find out the best possible configurations of transmit power and message rate for given numbers of vehicles in the network. The identified best configurations are then used online by roadside access points (AP) according to estimated number of vehicles. Simulation results show that this adaptive method significantly outperforms a fixed control method. © 2011 Springer-Verlag.

Theoretical perspectives in purchasing and supply chain management:an analysis of the literature

Purpose – This paper attempts to seek answers to four questions. Two of these questions have been borrowed (but adapted) from the work of Defee et al.: RQ1. To what extent is theory used in purchasing and supply chain management (P&SCM) research? RQ2. What are the prevalent theories to be found in P&SCM research? Following on from these questions an additional question is posed: RQ3. Are theory-based papers more highly cited than papers with no theoretical foundation? Finally, drawing on the work of Harland et al., the authors have added a fourth question: RQ4. To what extent does P&SCM meet the tests of coherence, breadth and depth, and quality necessary to make it a scientific discipline? Design/methodology/approach – A systematic literature review was conducted in accordance with the model outlined by Tranfield et al. for three journals within the field of “purchasing and supply chain management”. In total 1,113 articles were reviewed. In addition a citation analysis was completed covering 806 articles in total. Findings – The headline features from the results suggest that nearly a decade-and-a-half on from its development, the field still lacks coherence. There is the absence of theory in much of the work and although theory-based articles achieved on average a higher number of citations than non-theoretical papers, there is no obvious contender as an emergent paradigm for the discipline. Furthermore, it is evident that P&SCM does not meet Fabian's test necessary to make it a scientific discipline and is still some way from being a normal science. Research limitations/implications – This study would have benefited from the analysis of further journals, however the analysis of 1,113 articles from three leading journals in the field of P&SCM was deemed sufficient in scope. In addition, a further significant line of enquiry to follow is the rigour vs relevance debate. Practical implications – This article is of interest to both an academic and practitioner audience as it highlights the use theories in P&SCM. Furthermore, this article raises a number of important questions. Should research in this area draw more heavily on theory and if so which theories are appropriate? Social implications – The broader social implications relate to the discussion of how a scientific discipline develops and builds on the work of Fabian and Amundson. Originality/value – The data set for this study is significant and builds on a number of previous literature reviews. This review is both greater in scope than previous reviews and is broader in its subject focus. In addition, the citation analysis (not previously conducted in any of the reviews) and statistical test highlights that theory-based articles are more highly cited than non-theoretically based papers. This could indicate that researchers are attempting to build on one another's work.

High rate growth of nanocrystalline diamond films using high microwave power and pure nitrogen/methane/hydrogen plasma

In this work, we investigate the impact of minute amounts of pure nitrogen addition into conventional methane/hydrogen mixtures on the growth characteristics of nanocrystalline diamond (NCD) films by microwave plasma assisted chemical vapour deposition (MPCVD), under high power conditions. The NCD films were produced from a gas mixture of 4% CH4/H2 with two different concentrations of N2 additive and microwave power ranging from 3.0 kW to 4.0 kW, while keeping all the other operating parameters constant. The morphology, grain size, microstructure and texture of the resulting NCD films were characterized by using scanning electron microscope (SEM), micro-Raman spectroscopy and X-ray diffraction (XRD) techniques. N2 addition was found to be the main parameter responsible for the formation and for the key change in the growth characteristics of NCD films under the employed conditions. Growth rates ranging from 5.4 μm/h up to 9.6 μm/h were achieved for the NCD films, much higher than those usually reported in the literature. The enhancing factor of nitrogen addition on NCD growth rate was obtained by comparing with the growth rate of large-grained microcrystalline diamond films grown without nitrogen and discussed by comparing with that of single crystal diamond through theoretical work in the literature. This achievement on NCD growth rate makes the technology interesting for industrial applications where fast coating of large substrates is highly desirable.

An analysis of research on the future of purchasing and supply management

Business organisations are going through rapid external environmental and internal organisational changes due to increasing globalisation, E-business, and outsourcing. As a result, the future of purchasing and supply management—as a function within organisations, as a process that spans organisation boundaries and as a profession—raises important concerns for both organisations and the purchasing professional. This paper considers a broad and rather fragmented body of empirical evidence and analyses 42 relevant empirical studies on the future of purchasing and supply management. The major findings are reported in terms of changes in business contexts, purchasing strategy, structure, role and responsibility, system development and skills. Cross-sectional comparative analyses were also conducted to examine variation by sector, firm type, people's roles in purchasing, and country. A number of major implications for the purchasing function, process and professional bodies are presented together with suggestions for future research to address significant gaps in the current body of knowledge.

The people dimension in logistics and supply chain management:its role and importance

It is widely recognised that the effective application of logistics and supply chain management (SCM) has a vital role to play in European economic recovery. Experience suggests that success in achieving higher levels of supply chain integration (SCI) depends on both physical and technical components (the hard-wiring), as well as human and behavioural components (the soft-wiring). There is significant evidence that the latter has been largely neglected by the logistics and SCM community. Furthermore, it appears that the majority of supply chain improvement initiatives by practitioners have been primarily concerned with technological, structural and process issues. This chapter argues that the difficulties often encountered in attempting to put logistics and SCM theory into practice are largely a consequence of a lack of focus and understanding of the people dimension. Based on this discussion, it offers some suggestions for improvement in this area to supply chain professionals.

An Investigation into Outsourcing Practice in Ireland:A New Direction in Logistics and Supply Chain Management

Companies are increasingly focusing on the development of core competencies as an integral part of their overall strategy development and implementation. The corollary of this is that functions regarded as being non-core are being outsourced. This paper investigates the case for and against outsourcing and in addition what is happening in Ireland regards outsourcing. Furthermore to analysis of current literature in the field, an Irish-wide postal and e-mail survey, as well as three case studies revealed many interesting facts. The key findings of the work are manufacturing outsourcing is now the most popular function to be outsourced for both small to medium sized enterprises (SMEs) and large enterprises. Large enterprises (LEs) do not prepare or examine hidden costs more than SMEs, nor do they differ much in relation to the use of consultants. Furthermore, the importance of time spent on preparing or producing contract, and the impact the contract can have on the supplier-buyer relation do not differ significantly. It was found that most companies outsourced within Ireland, which led to further investigation in that area. In relation to logistics outsourcing specifically, this has become very important in the supply chain over the last 20 years as an activity that was traditionally handled by firms as a support function. At that time logistics activities such as warehousing, distribution, transportation and inventory management were given low priority compared with other business functions within the organisation. However, since the customer has become more demanding, the logistics function has now become a source of competitive advantage and there has been a growing emphasis on providing good customer service.

Integrated logistics and supply chain management:the state of practice in Ireland

The Republic of Ireland and Northern Ireland were provided with aid to offset locational disadvantages in the run up to the Single European Market. Since then the Republic has emerged as the fastest growing member of the E.U. Success has not been underpinned by the transport system, suggesting that business has had to overcome locational disadvantages by strong performance elsewhere in the supply chain. The evidence indicates that there are Irish firms operating supply chain management techniques at a truly international standard. The problem is that there are so few in that category Meeting Ireland’s competitiveness challenge means closing the gap between the small group of large and foreign-owned firms, which display excellence in SCM, and the larger group of indigenous small and medium size businesses, which do not.

Corporate taxation, corporate power, and corporate harm

Globalisation has increased corporate tax competition amongst states and facilitated widespread corporate tax avoidance. Some of the largest businesses now pay little or no tax: in some cases with the active assistance of governments. This article examines contemporary corporation tax policies, outlines some of the key methods corporations use to minimise their tax liabilities, explores the interdependencies between the demand for reduced tax liabilities and the professional infrastructure of tax planning and avoidance, and examines how the contemporary political economy of corporate taxation enhances the bargaining power of transnational corporations in the implementation of tax policy.

Adaptive power and rate control for QoS guarantee of DSRC based collaborative road safety applications

In this paper we propose an adaptive power and message rate control method for safety applications at road intersections. The design objectives are to firstly provide guaranteed QoS support to both high priority emergency safety applications and low priority routine safety applications and secondly maximize channel utilization. We use an offline simulation based approach to find out the best possible configurations of transmit power and message rate for given numbers of vehicles in the network with certain safety QoS requirements. The identified configurations are then used online by roadside access points (AP) adaptively according to estimated number of vehicles. Simulation results show that this adaptive method could provide required QoS support to safety applications and it significantly outperforms a fixed control method. © 2013 International Information Institute.

Wireless power and data transfer via a common inductive link using frequency division multiplexing

For wireless power transfer (WPT) systems, communication between the primary side and the pickup side is a challenge because of the large air gap and magnetic interferences. A novel method, which integrates bidirectional data communication into a high-power WPT system, is proposed in this paper. The power and data transfer share the same inductive link between coreless coils. Power/data frequency division multiplexing technique is applied, and the power and data are transmitted by employing different frequency carriers and controlled independently. The circuit model of the multiband system is provided to analyze the transmission gain of the communication channel, as well as the power delivery performance. The crosstalk interference between two carriers is discussed. In addition, the signal-to-noise ratios of the channels are also estimated, which gives a guideline for the design of mod/demod circuits. Finally, a 500-W WPT prototype has been built to demonstrate the effectiveness of the proposed WPT system.

Power and spectral optimization of random distributed feedback fiber lasers

We present the optimization of power and spectral performances of the random DFB fiber laser using the balance equation set. The numerical results are in good in agreement with experiments. © 2012 OSA.

A new regime for high rate growth of nanocrystalline diamond films using high power and CH4/H2/N2/O2 plasma

In this work, we report high growth rate of nanocrystalline diamond (NCD) films on silicon wafers of 2 inches in diameter using a new growth regime, which employs high power and CH4/H2/N2/O2 plasma using a 5 kW MPCVD system. This is distinct from the commonly used hydrogen-poor Ar/CH4 chemistries for NCD growth. Upon rising microwave power from 2000 W to 3200 W, the growth rate of the NCD films increases from 0.3 to 3.4 μm/h, namely one order of magnitude enhancement on the growth rate was achieved at high microwave power. The morphology, grain size, microstructure, orientation or texture, and crystalline quality of the NCD samples were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction, and micro-Raman spectroscopy. The combined effect of nitrogen addition, microwave power, and temperature on NCD growth is discussed from the point view of gas phase chemistry and surface reactions. © 2011 Elsevier B.V. All rights reserved.

Poland's power and influence in the European union:the case of its Eastern policy

This paper seeks to assess the degree to which Poland exercises power and influence in the European Union. It employs Poland's policy towards its eastern neighbours as a case study, and, in doing so, contributes to two wider scholarly debates on how EU policy towards Russia, Ukraine and Belarus is made, and also the broader question of the evolving nature of the relationship between the European Union and its member states. In doing so, it employs a synthetic framework that brings together the approaches for studying the power and influence of a given member state that were developed by Wallace et al. (2005), Tallberg (2008) and Moravcsik (1991, 1993, 1998). It concludes that Polish influence has been low.