Showing papers by "University of Greenwich published in 1995"
TL;DR: There is a comprehensive introduction to the applied models of probability that stresses intuition, and both professionals, researchers, and the interested reader will agree that this is the most solid and widely used book for probability theory.
Abstract: The Seventh Edition of the successful Introduction to Probability Models introduces elementary probability theory and stochastic processes. This book is particularly well-suited to those applying probability theory to the study of phenomena in engineering, management science, the physical and social sciences, and operations research. Skillfully organized, Introduction to Probability Models covers all essential topics. Sheldon Ross, a talented and prolific textbook author, distinguishes this book by his effort to develop in students an intuitive, and therefore lasting, grasp of probability theory. Ross' classic and best-selling text has been carefully and substantially revised. The Seventh Edition includes many new examples and exercises, with the majority of the new exercises being of the easier type. Also, the book introduces stochastic processes, stressing applications, in an easily understood manner. There is a comprehensive introduction to the applied models of probability that stresses intuition. Both professionals, researchers, and the interested reader will agree that this is the most solid and widely used book for probability theory. Features: * Provides a detailed coverage of the Markov Chain Monte Carlo methods and Markov Chain covertimes * Gives a thorough presentation of k-record values and the surprising Ignatov's * theorem * Includes examples relating to: "Random walks to circles," "The matching rounds problem," "The best prize problem," and many more * Contains a comprehensive appendix with the answers to approximately 100 exercises from throughout the text * Accompanied by a complete instructor's solutions manual with step-by-step solutions to all exercises New to this edition: * Includes many new and easier examples and exercises * Offers new material on utilizing probabilistic method in combinatorial optimization problems * Includes new material on suspended animation reliability models * Contains new material on random algorithms and cycles of random permutations
4,945 citations
251 citations
TL;DR: The problem is proved to be NP-hard in the strong sense even when m = 2, and a heuristic with a worst-case ratio bound of 2-1/m is presented.
Abstract: This paper introduces a new two-stage assembly scheduling problem. There are m machines at the first stage, each of which produces a component of a job. When all m components are available, a single assembly machine at the second stage completes the job. The objective is to schedule jobs on the machines so that the makespan is minimized. We show that the search for an optimal solution may be restricted to permutation schedules. The problem is proved to be NP-hard in the strong sense even when m = 2. A schedule associated with an arbitrary permutation of jobs is shown to provide a worst-case ratio bound of two, and a heuristic with a worst-case ratio bound of 2-1/m is presented. The compact vector summation technique is applied for finding approximation solutions with worst-case absolute performance guarantees.
233 citations
TL;DR: It is suggested that, given appropriate attention to rigour, phenomenological methodology could become the basic instrument in the reform of nursing research as it moves from the positivist to the humanist paradigm.
Abstract: In its quest for knowledge, nursing has relied heavily on the positivist approach to scientific enquiry. Phenomenological enquiry identifies the essence of a phenomenon and accurately describes it through the lived experience. Through consistency in the use of the methodology, and avoidance of method slurring, academic rigour can be maintained. It is advocated that the phenomenological method is congruent with nursing ideals where humanistic knowledge is valued. Nurses and phenomenologists share skills in observation, interviewing, interaction and interpersonal relationships in the appreciation of the individual's perception of an experience. Through the development of professional practice, nurses thus gain the tools to assist them in phenomenological research. It is suggested that, given appropriate attention to rigour, phenomenological methodology could become the basic instrument in the reform of nursing research as it moves from the positivist to the humanist paradigm.
163 citations
TL;DR: The theory of heteroaggregation has been continually developed to extend the use of a formula to encapsulate all particle type variations as discussed by the authors, and it is necessary for these complex equations to be related to experimental conditions.
145 citations
TL;DR: In this article, a finite volume (FV) procedure is described for solving the elastic solid mechanics equations in three dimensions on an unstructured mesh, for bodies undergoing thermal or mechanical loads.
Abstract: A Finite Volume (FV) procedure is described for solving the elastic solid mechanics equations in three dimensions on an unstructured mesh, for bodies undergoing thermal or mechanical loads. The FV procedure is developed in parallel with the conventional FE Galerkin procedure so that the differences in each approach may be clearly distinguished. The matrix form of the FV procedure is described, and is implemented in parallel with the FE procedure, both for two-dimensional quadrilateral and three-dimensional brick meshes. The FV and FE procedures are then compared against a range of benchmark problems that test the basic capability of the FV technique. It is shown to be approximately as accurate as the FE procedure on similar meshes, though its system matrix set-up time is twice as long for a node by node set-up procedure.
127 citations
TL;DR: The results are consistent with the view that activation of the parvocellular vasopressin system has an important role in the adaptation of the HPA axis to experimentally‐induced chronic stress of arthritis.
Abstract: 1. Adjuvant-induced arthritis (AA) is an experimental inflammation of the joints that results in chronic activation of the hypothalamo-pituitary-adrenal (HPA) axis. 2. In this study the role of hypothalamic corticotrophin-releasing factor (CRF) and arginine vasopressin (AVP) in the regulation of the HPA axis in this condition both in Sprague-Dawley (SD), and Piebald-Viral-Glaxo (PVG) rats has been further characterized. 3. The increase in AVP peptide content of portal blood (as early as day 11), just prior to the onset of arthritis is confirmed and further increases, peaking at day 16 are shown, coincident with the progression of inflammation in the PVG rats. 4. The increase in AVP is associated with a significant increase in the expression of AVP but not CRF mRNAs in the medial parvocellular division of the hypothalamic paraventricular nucleus (PVN) of arthritic SD rats. 5. In the presence of maximal inflammation of SD rats there was a significant decrease in the maximum binding of [125I]-Tyr-oCRF to anterior pituitary membranes, whereas AVP receptor concentration in anterior pituitary membranes from both PVG and SD rats showed a significant increase with respect to controls. 6. The basal adrenocorticotrophin (ACTH) secretion in vitro was similar in both control and arthritic SD rats but that from arthritic PVG rat pituitaries was significantly greater than the respective controls (436 +/- 91 v 167 +/- 23 pg/tube). The ACTH response of pituitaries of arthritic PVG rats to CRF or the combination of CRF and AVP was significantly higher compared with the controls, although the ACTH response of arthritic SD rat pituitaries was unchanged. 7. The results are consistent with the view that activation of the parvocellular vasopressin system has an important role in the adaptation of the HPA axis to experimentally-induced chronic stress of arthritis.
115 citations
01 Jan 1995
TL;DR: The Articles of Agreement constitute the actual contract between the parties whilst the Conditions of Contract stipulate certain provisions for its execution as mentioned in this paper, and the conditions of contract are defined by the parties.
Abstract: The Articles of Agreement constitute the actual contract between the parties whilst the Conditions of Contract stipulate certain provisions for its execution.
100 citations
TL;DR: In this paper, a two dimensional finite volume (FV) approach to the solution of elastic / visco-plastic solid mechanics problems is described. The numerical procedure is an extension of that developed by Fryer et al for linear elastic materials and utilizes an unstructured mesh.
75 citations
01 Dec 1995
TL;DR: Experiments indicate that the resulting code is up to an order of magnitude faster than existing state- of-the-art techniques such as Multilevel Recursive Spectral Bisection, while providing partitions of equiv alent quality.
Abstract: A new method is described for optimizing graph parti tions that arise in mapping unstructured mesh calcula tions to parallel computers. The method employs a combination of iterative techniques to evenly balance the workload and minimize the number and volume of interprocessor communications. When combined with a fast direct-partitioning technique such as the Greedy algorithm to give an initial partition, the resulting two- stage process proves itself to be a powerful and flexi ble solution to the static graph-partitioning problem. A clustering technique can also be employed to speed up the whole process. Experiments, on graphs with up to a million nodes, indicate that the resulting code is up to an order of magnitude faster than existing state- of-the-art techniques such as Multilevel Recursive Spectral Bisection, while providing partitions of equiv alent quality.
73 citations
TL;DR: In this article, a new ostracods biozonation scheme is proposed, comprising three zones (Theriosynoecum forbesi Zone, approximately equal to the Purbeck; TheriosynoECum alleni Zone, roughly equal to Hastings Beds Group; Therioecum fittoni Zone, approximated to the Weald Clay Group), subdivided into eight subzones on the basis of the ranges of Cypridea species.
TL;DR: Comparison with previous studies on lignin peroxidase catalysis suggests a second role for veratryl alcohol radical cation in the enzyme action: it may exist as an enzyme-bound species that has either a longer lifetime or a higher reduction potential than the free radical cations in bulk solution.
TL;DR: In this paper, the results of stable isotope analyses of dimitobelid belemnites from the Albian Gearle Siltstone, Carnarvon Basin, Western Australia were presented.
Abstract: Although previous geological, palaeobotanical and geochemical data from the Albian of Australia have suggested the possibility of cool palaeoclimates, there are few well-constrained stable isotope palaeotemperatures studies from this region. In this paper we present the results of stable isotope analyses of dimitobelid belemnites from the Albian Gearle Siltstone, Carnarvon Basin, Western Australia. Oxygen isotope values for diagenetically least-altered samples give values ranging between δ 18 O −0.02 and 0.85% PDB, which equate to a mean palaeotemperature of 10.08°C (assuming δ w of −1.2% SMOW). This value is broadly consistent with recently published isotope data from the Albian Antarctic and with estimates for mid-Cretaceous latitudinal temperature gradients, implying that cool palaeoclimates occurred during a period of 9Greenhouse9 Earth.
TL;DR: It is proposed that critical incident analysis is a valuable educational tool which enables nursing/midwifery students to draw on past experiences and make sense of them, not only facilitating learning from clinical practice but also going some way towards bridging the gap between theory and practice.
TL;DR: The mineralogy and REE geochemistry of thin, clay-rich beds from Turonian chalks of Lower Saxony (Germany) has been studied in this article, where two types of clayrich beds are present.
TL;DR: The question of free movement vs. exclusion within the European Union (EU) can be addressed satisfactorily only if the focus on the state or the political elite alone is too one-sided and misses the more complex factors bearing upon EU policymaking in this area.
Abstract: This article argues that the question of free movement vs. exclusion within the European Union (EU) can be addressed satisfactorily only if we move away from the narrow state-centrism inherent in the current debate. What is required is to `open the state concept and examine the implications of state-society relations for EU policy making. Once this is done it can be seen that the exclusionist stance of the immigration policy and the essentially intergovernmental nature of the policy making are due to an implicit contract between states and constituents implied by the concepts of nationality and citizenship. According to this perspective the focus on the state or the political elite alone is too one-sided and misses the more complex factors bearing upon EU policy making in this area. (EXCERPT)
TL;DR: In this article, the authors consider the problem of estimating the expected growth curve of a set of height trajectories from Sitka spruce sample plots using a diffusion model and a stochastic differential equation formulation.
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01 Dec 1995TL;DR: The two-machine flow shop no-wait problem with a single server is reduced to the Gilmore{Gomory traveling salesman problem and solved in polynomial time.
Abstract: This paper examines scheduling problems in which the setup phase of each operation needs to be attended by a single server, common for all jobs and different from the processing machines. The objective in each situation is to minimize the makespan. For the processing system consisting of two parallel dedicated machines we prove that the problem of finding an optimal schedule isNP-hard in the strong sense even if all setup times are equal or if all processing times are equal. For the case of m parallel dedicated machines, a simple greedy algorithm is shown to create a schedule with the makespan that is at most twice the optimum value. For the two machine case, an improved heuristic guarantees a tight worst-case ratio of 3/2. We also describe several polynomially solvable cases of the later problem. The two-machine flow shop and the open shop problems with a single server are also shown to be NP-hard in the strong sense. However, we reduce the two-machine flow shop no-wait problem with a single server to the Gilmore{Gomory traveling salesman problem and solve it in polynomial time. c 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 304{328, 2000
TL;DR: In this paper, the authors discuss the problem of single-use planning for greenways and urban green spaces and conclude that product diversification and product differentiation must take place, and that special varieties of greenway are needed for special purposes.
TL;DR: In this article, Druker and White, principal lecturer and senior lecturer respectively in the Business School at the University of Greenwich, draw on interviews and on a survey of personnel managers in the construction industry, to consider the role and responsibilities of personnel practitioners in construction.
Abstract: Janet Druker and Geoffrey White, principal lecturer and senior lecturer respectively in the Business School at the University of Greenwich, draw on interviews and on a postal survey of personnel managers in the construction industry, to consider the role and responsibilities of personnel practitioners in construction. They point to the changing balance of employment within the construction firm and the greater involvement of personnel with non-manual employees. They highlight the importance of various forms of sub-contracting as a means of strengthening management control at site level. They suggest that the centrally located personnel function may well be close to strategy makers but ultimately the role was found to be advisory with a limited capacity for direct intervention.
TL;DR: The increases in hypothalamic SP in AA, together with the data demonstrating that HPA axis activity is enhanced in AA following injection of a SP antagonist, are consistent with the hypothesis that SP is acting as an inhibitor of CRH expression in this model of chronic inflammatory stress.
TL;DR: In this paper, the interaction of an externally imposed magnetic and electric field on the laminar flow of a conducting fluid in a channel is studied using computational techniques, where the Navier-Stokes equations and the equations describing the electromagnetic field are solved simultaneously in a single control volume-type computational fluid dynamic code, in a moderate Hartmann number and interaction parameter regime.
04 Sep 1995
TL;DR: An overview of some strategies for mapping unstructured meshes onto processor grids shows that the mapping can make a considerable difference to the communication overhead in the parallel solution time, particularly as the number of processors increase.
Abstract: We give an overview of some strategies for mapping unstructured meshes onto processor grids. Sample results show that the mapping can make a considerable difference to the communication overhead in the parallel solution time, particularly as the number of processors increase.
TL;DR: In this paper, the issue of valuation accuracy and the methodology for assessing it has been the subject of recent academic research and debate and the authors focus on three main areas related to the topic of valuation accuracies: methodological problems and concerns of attempting to assess the relationship between prior valuations and subsequent transaction prices.
Abstract: Summary The issue of valuation accuracy is important for property professionals and investment analysts. The issue of accuracy and the methodology for assessing it has been the subject of recent academic research and debate. This paper focuses on three main areas related to the topic of valuation accuracy. Firstly, it examines some of the methodological problems and concerns of attempting to assess the relationship between prior valuations and subsequent transaction prices. Secondly, previous empirical research on this topic is critically examined. Academic critiques of previous empirical research are reviewed. Finally, a sample of property transactions is analysed in order to assess the relationship with the previous valuation. It is concluded that the empirical investigation of valuation accuracy is fraught with methodological problems. Moreover, it is tentatively concluded that there is likely to be an element of error in the valuation process but that it is unlikely that valuation bias is significant.
TL;DR: In this paper, the authors used liquid chromatographic techniques to identify the major radioactive species in the exhaust of a Perkins Prima DI diesel engine, which was found to be [7,10-14 C]benzo[a ]pyrene.
TL;DR: In this article, the authors compared the performance and results obtained from a rig of each of the two major types of erosion testing devices used throughout the world for quantifying particle impact erosion against a solid surface.
24 Apr 1995
TL;DR: In this paper, the authors compared the results obtained from the electrostatic modelling of such sensors with those obtained from experiments and showed that the experimental results were not significantly different from those obtained in the literature.
Abstract: Granular airborne particles generally carry very small amounts of electric charge as a consequence of charging by the triboelectric effect. The presence of such particles induces charge of opposite polarity on a stationary conducting electrode. The amount of charge carried by the particles and the trajectories of the particles have significant random components and the signals produced are of very low level. The signal processing is further complicated by the random variation in the concentration of particles, i.e., the solid/gas ratio. This paper compares the results obtained from the electrostatic modelling of such sensors with those obtained from experiments.
TL;DR: In this paper, the major physical, chemical, and microbiological fate processes of selected herbicides in riverine systems are discussed and strategies for mathematically modelling the environmental fate of pesticides in rivers are reviewed and areas of future work identified.
TL;DR: In this paper, a class of doubly stochastic Poisson processes, which is termed a Markov-modulated Poisson process, is studied, and the maximum likelihood method is used to make inferences about the Markov modulated poisson process.
Abstract: A class of doubly stochastic Poisson processes, which is termed a Markov-modulated Poisson process, is studied. The maximum likelihood method is used to make inferences about the Markov-modulated Poisson process. Expressions are derived for the likelihood function and for second-order properties of both counts and intervals. A simple two-state model is applied to a set of exposure data and to simulated data. Bivariate generalization of this process is also studied.