137 resultados para exponential sums
Resumo:
In order to simulate stiff biochemical reaction systems, an explicit exponential Euler scheme is derived for multidimensional, non-commutative stochastic differential equations with a semilinear drift term. The scheme is of strong order one half and A-stable in mean square. The combination with this and the projection method shows good performance in numerical experiments dealing with an alternative formulation of the chemical Langevin equation for a human ether a-go-go related gene ion channel mode
Resumo:
- Provided a practical variable-stepsize implementation of the exponential Euler method (EEM). - Introduced a new second-order variant of the scheme that enables the local error to be estimated at the cost of a single additional function evaluation. - New EEM implementation outperformed sophisticated implementations of the backward differentiation formulae (BDF) of order 2 and was competitive with BDF of order 5 for moderate to high tolerances.
Resumo:
In this paper, a singularly perturbed ordinary differential equation with non-smooth data is considered. The numerical method is generated by means of a Petrov-Galerkin finite element method with the piecewise-exponential test function and the piecewise-linear trial function. At the discontinuous point of the coefficient, a special technique is used. The method is shown to be first-order accurate and singular perturbation parameter uniform convergence. Finally, numerical results are presented, which are in agreement with theoretical results.
Resumo:
The business value of Enterprise Resource Planning systems (ERP systems), and in general large software implementations, has been extensively debated in both popular press and in the academic literature for over two decades. Organisations invest enormous sums of money and resources in Enterprise Resource Planning systems (and related infrastructure), presumably expecting positive impacts to the organisation and its functions. Some studies have reported large productivity improvements and substantial benefits from ERP systems, while others have reported that ERP systems have not had any bottom-line impact. This paper discusses initial findings from a study that focuses on identifying and assessing important ERP impacts in 23 Australian public sector organizations.
Resumo:
Organisations invest enormous sums of money in acquiring Enterprise Resource Planning (ERP) systems, presumably expecting positive impacts to the organisation and its functions. Despite the optimistic motives some ERP projects have reported nil or detrimental impacts. This paper studies the proposition that the size of an organisation (e.g. small, large) may have contributed to the differences in receiving benefits reported in prior studies in this domain. The alleged differences in organisational performance are empirically measured using a prior validated model, using five constructs and fortytwo sub-constructs. Information is gathered from three hundred and ten respondents representing twenty-seven public sector organisations. Results suggests that (1) larger organisations have received more benefits compared to small organisations, (2) small organisations demonstrated higher reliance on their ERP systems, (3) employment cohorts demonstrate significant differences in perceived benefits in small and large organisations.
Resumo:
The central cultural experience of modernity has been change, both the ‘creative destruction’ of existing structures, and the growth, often exponential, of new knowledge. During the twentieth century, the central cultural platform for the collective experience of modernising societies changed too, from page and stage to the screen – from publishing, the press and radio to cinema, television and latterly computer screens. Despite the successive dominance of new media, none has lasted long at the top. The pattern for each was to give way to a successor platform in popularity, but to continue as part of an increasingly crowded media menu. Modern media are supplemented not supplanted by their successors.
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In this paper, we offer some observations regarding the sex industry, in particular the pornography and erotica sectors. Marketing literature observing pornography and erotica is scant. We find that following exponential growth of the sex industry (given use of the Internet) an evaluation of consumer behaviour and marketing practices is justified. In order to begin a study of these industry sectors, we find it necessary to define both pornography and erotica. Following the development of definitions, we consider these industries from a marketing perspective in the hope that we may encourage research into these areas.
Resumo:
Phase-type distributions represent the time to absorption for a finite state Markov chain in continuous time, generalising the exponential distribution and providing a flexible and useful modelling tool. We present a new reversible jump Markov chain Monte Carlo scheme for performing a fully Bayesian analysis of the popular Coxian subclass of phase-type models; the convenient Coxian representation involves fewer parameters than a more general phase-type model. The key novelty of our approach is that we model covariate dependence in the mean whilst using the Coxian phase-type model as a very general residual distribution. Such incorporation of covariates into the model has not previously been attempted in the Bayesian literature. A further novelty is that we also propose a reversible jump scheme for investigating structural changes to the model brought about by the introduction of Erlang phases. Our approach addresses more questions of inference than previous Bayesian treatments of this model and is automatic in nature. We analyse an example dataset comprising lengths of hospital stays of a sample of patients collected from two Australian hospitals to produce a model for a patient's expected length of stay which incorporates the effects of several covariates. This leads to interesting conclusions about what contributes to length of hospital stay with implications for hospital planning. We compare our results with an alternative classical analysis of these data.
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One of the oldest problems in philosophy concerns the relationship between free will and moral responsibility. If we adopt the position that we lack free will, in the absolute sense—as have most philosophers who have addressed this issue—how can we truly be held accountable for what we do? This paper will contend that the most significant and interesting challenge to the long-standing status-quo on the matter comes not from philosophy, jurisprudence, or even physics, but rather from psychology. By examining this debate through the lens of contemporary behaviour disorders, such as ADHD, it will be argued that notions of free will, along with its correlate, moral responsibility, are being eroded through the logic of psychology which is steadily reconfiguring large swathes of familiar human conduct as pathology. The intention of the paper is not only to raise some concerns over the exponential growth of behaviour disorders, but also, and more significantly, to flag the ongoing relevance of philosophy for prying open contemporary educational problems in new and interesting ways.
Resumo:
One of the oldest problems in philosophy concerns the relationship between free will and moral responsibility. If we adopt the position that we lack free will, in the absolute sense—as have most philosophers who have addressed this issue—how can we truly be held accountable for what we do? This paper will contend that the most significant and interesting challenge to the long-standing status-quo on the matter comes not from philosophy, jurisprudence, or even physics, but rather from psychology. By examining this debate through the lens of contemporary behaviour disorders, such as ADHD, it will be argued that notions of free will, along with its correlate, moral responsibility, are being eroded through the logic of psychology which is steadily reconfiguring large swathes of familiar human conduct as pathology. The intention of the paper is not only to raise some concerns over the exponential growth of behaviour disorders, but also, and more significantly, to flag the ongoing relevance of philosophy for prying open contemporary educational problems in new and interesting ways.
Resumo:
Significant sums of money are invested in developing technological innovations that have low levels and rates of adoption. Several approaches have been put forward in an effort to improve rates of adoption. This paper presents the results of study that examined the innovation fit of key technological innovations in the beef industry. Findings indicate that be assessing the innovation fit throughout the R&D process researchers and end users can collaborate to improve the innovation fit and the rate of adoption. The paper also put forward a model that demonstrates the linkages between R&D, adoption and innovation fit.
Resumo:
The construction industry is known to be an important contributor towards the gross domestic product of many countries. Moreover, the health of the construction industry is positively correlated to the economic growth of a country and in many economies public sector clients account for a major share of construction works. Given this strength, it is important for public sector clients to initiate innovations aimed at the betterment of the industry. In this context, concern about sustainable development has been a major driver of some innovative initiatives in construction industries worldwide. Furthermore, the Government of Hong Kong regards both sustainability and community development as important criteria when planning and procuring construction projects. This paper is based on a case study of a public sector development project in Hong Kong, and presents the salient features of the procurement and contractual systems adopted in the project, which foster sustainability and community development. The reported interim findings are based on a preliminary document analysis that is part of an ongoing longitudinal case study into the project. The document analysis takes a three-pronged approach in terms of how the procurement and contractual systems foster economic, environmental and social sustainability, and sums up their impact on the community as a whole.
Resumo:
The population Monte Carlo algorithm is an iterative importance sampling scheme for solving static problems. We examine the population Monte Carlo algorithm in a simplified setting, a single step of the general algorithm, and study a fundamental problem that occurs in applying importance sampling to high-dimensional problem. The precision of the computed estimate from the simplified setting is measured by the asymptotic variance of estimate under conditions on the importance function. We demonstrate the exponential growth of the asymptotic variance with the dimension and show that the optimal covariance matrix for the importance function can be estimated in special cases.
Resumo:
Objective: To investigate the acute effects of isolated eccentric and concentric calf muscle exercise on Achilles tendon sagittal thickness. ---------- Design: Within-subject, counterbalanced, mixed design. ---------- Setting: Institutional. ---------- Participants: 11 healthy, recreationally active male adults. ---------- Interventions: Participants performed an exercise protocol, which involved isolated eccentric loading of the Achilles tendon of a single limb and isolated concentric loading of the contralateral, both with the addition of 20% bodyweight. ---------- Main outcome measurements: Sagittal sonograms were acquired prior to, immediately following and 3, 6, 12 and 24 h after exercise. Tendon thickness was measured 2 cm proximal to the superior aspect of the calcaneus. ---------- Results: Both loading conditions resulted in an immediate decrease in normalised Achilles tendon thickness. Eccentric loading induced a significantly greater decrease than concentric loading despite a similar impulse (−0.21 vs −0.05, p<0.05). Post-exercise, eccentrically loaded tendons recovered exponentially, with a recovery time constant of 2.5 h. The same exponential function did not adequately model changes in tendon thickness resulting from concentric loading. Even so, recovery pathways subsequent to the 3 h time point were comparable. Regardless of the exercise protocol, full tendon thickness recovery was not observed until 24 h. ---------- Conclusions: Eccentric loading invokes a greater reduction in Achilles tendon thickness immediately after exercise but appears to recover fully in a similar time frame to concentric loading.
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This article examines the growing phenomenon of online dating and intimacy in the 21st century. The exponential rise of communications technologies, which is both reflective and constitutive of an increasingly networked and globalized society, has the potential to significantly influence the nature of intimacy in everyday life. Yet, to date, there has been a minimal response by sociologists to seek, describe and understand this influence. In this article, we present some of the key findings of our research on online dating in Australia, in order to foster a debate about the sociological impacts on intimacy in the postmodern world. Based on a web audit of more than 60 online dating sites and in-depth interviews with 23 users of online dating services, we argue that recent global trends are influencing the uptake of online technologies for the purposes of forming intimate relations. Further, some of the mediating effects of these technologies – in particular, the hypercommunication – may have specific implications for the nature of intimacy in the global era.