984 resultados para Random Allocation
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An iterative based strategy is proposed for finding the optimal rating and location of fixed and switched capacitors in distribution networks. The substation Load Tap Changer tap is also set during this procedure. A Modified Discrete Particle Swarm Optimization is employed in the proposed strategy. The objective function is composed of the distribution line loss cost and the capacitors investment cost. The line loss is calculated using estimation of the load duration curve to multiple levels. The constraints are the bus voltage and the feeder current which should be maintained within their standard range. For validation of the proposed method, two case studies are tested. The first case study is the semi-urban 37-bus distribution system which is connected at bus 2 of the Roy Billinton Test System which is located in the secondary side of a 33/11 kV distribution substation. The second case is a 33 kV distribution network based on the modification of the 18-bus IEEE distribution system. The results are compared with prior publications to illustrate the accuracy of the proposed strategy.
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A PCR assay, using three primer pairs, was developed for the detection of Ureaplasma urealyticum, parvo biovar, mba types 1, 3, and 6, in cultured clinical specimens. The primer pairs were designed by using the polymorphic base positions within a 310- to 311-bp fragment of the 5* end and upstream control region of the mba gene. The specificity of the assay was confirmed with reference serovars 1, 3, 6, and 14 and by the amplified-fragment sizes (81 bp for mba 1, 262 bp for mba 3, and 193 bp for mba 6). A more sensitive nested PCR was also developed. This involved a first-step PCR, using the primers UMS-125 and UMA226, followed by the nested mba-type PCR described above. This nested PCR enabled the detection and typing of small numbers of U. urealyticum cells, including mixtures, directly in original clinical specimens. By using random amplified polymorphic DNA (RAPD) PCR with seven arbitrary primers, we were also able to differentiate the two biovars of U. urealyticum and to identify 13 RAPD-PCR subtypes. By applying these subtyping techniques to clinical samples collected from pregnant women, we established that (i) U. urealyticum is often a persistent colonizer of the lower genital tract from early midtrimester until the third trimester of pregnancy, (ii) mba type 6 was isolated significantly more often (P 5 0.048) from women who delivered preterm than from women who delivered at term, (iii) no particular ureaplasma subtype(s) was associated with placental infections and/or adverse pregnancy outcomes, and (iv) the ureaplasma subtypes most frequently isolated from women were the same subtypes most often isolated from infected placentas.
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In this paper we investigate the distribution of the product of Rayleigh distributed random variables. Considering the Mellin-Barnes inversion formula and using the saddle point approach we obtain an upper bound for the product distribution. The accuracy of this tail-approximation increases as the number of random variables in the product increase.
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utomatic pain monitoring has the potential to greatly improve patient diagnosis and outcomes by providing a continuous objective measure. One of the most promising methods is to do this via automatically detecting facial expressions. However, current approaches have failed due to their inability to: 1) integrate the rigid and non-rigid head motion into a single feature representation, and 2) incorporate the salient temporal patterns into the classification stage. In this paper, we tackle the first problem by developing a “histogram of facial action units” representation using Active Appearance Model (AAM) face features, and then utilize a Hidden Conditional Random Field (HCRF) to overcome the second issue. We show that both of these methods improve the performance on the task of pain detection in sequence level compared to current state-of-the-art-methods on the UNBC-McMaster Shoulder Pain Archive.
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Historically a significant gap between male and female wages has existed in the Australian labour market. Indeed this wage differential was institutionalised in the 1912 arbitration decision which determined that the basic female wage would be set at between 54 and 66 per cent of the male wage. More recently however, the 1969 and 1972 Equal Pay Cases determined that male/female wage relativities should be based upon the premise of equal pay for work of equal value. It is important to note that the mere observation that average wages differ between males and females is not sine qua non evidence of sex discrimination. Economists restrict the definition of wage discrimination to cases where two distinct groups receive different average remuneration for reasons unrelated to differences in productivity characteristics. This paper extends previous studies of wage discrimination in Australia (Chapman and Mulvey, 1986; Haig, 1982) by correcting the estimated male/female wage differential for the existence of non-random sampling. Previous Australian estimates of male/female human capital basedwage specifications together with estimates of the corresponding wage differential all suffer from a failure to address this issue. If the sample of females observed to be working does not represent a random sample then the estimates of the male/female wage differential will be both biased and inconsistent.
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Debate about the relationships between business planning and performance has been active for decades (Bhidé, 2000; Mintzberg, 1994). While results have been inconclusive, this topic still strongly divides the research community (Brinckmann et al., 2010; Chwolka & Raith, 2011; Delmar & Shane, 2004; Frese, 2009; Gruber, 2007; Honig & Karlsson, 2004). Previous research explored the relationships between innovation and the venture creation process (Amason et al., 2006, Dewar & Dutton, 1986; Jennings et al., 2009). However, the relationships between business planning and innovation have mostly been invoked indirectly in the strategy and entrepreneurship literatures through the notion of uncertainty surrounding the development of innovation. Some posited that planning may be irrelevant due to the iterative process, the numerous changes innovation development entails and the need to be flexible (Brews & Hunt, 1999). Others suggested that planning may facilitate the achievement of goals and overcoming of obstacles (Locke and Latham, 2000), guide the venture in its allocation of resources (Delmar and Shane, 2003) and help to foster the communication about the innovation being developed (Liao & Welsh, 2008). However, the nature and extents of the relationships between business planning, innovation and performance are still largely unknown. Moreover, if the reasons why ventures should engage (Frese, 2009) –or not- (Honig, 2004) in business planning have been investigated quite extensively (Brinckmann et al., 2010), the specific value of business planning for nascent firms developing innovation is still unclear. The objective of this paper is to shed some light on these important aspects by investigating the two following questions on a large sample of random nascent firms: 1) how is business planning use over time by new ventures developing different types and degrees of innovation? 2) how do business planning and innovation impact the performance of the nascent firms? Methods & Key propositions This PSED-type study draws its data from the first three waves of the CAUSEE project where 30,105 Australian households were randomly contacted by phone using a methodology to capture emerging firms (Davidsson, Steffens, Gordon, Reynolds, 2008). This screening led to the identification of 594 nascent ventures (i.e., firms that were not operating yet at the time of the identification) that were willing to participate in the study. Comprehensive phone interviews were conducted with these 594 ventures. Likewise, two comprehensive follow-ups were organised 12 months and 24 months later where 80% of the eligible cases of the previous wave completed the interview. The questionnaire contains specific sections investigating business plans such as: presence or absence, degree of formality and updates of the plan. Four types of innovation are measured along three degrees of intensity to produce a comprehensive continuous measure ranging from 0 to 12 (Dahlqvist & Wiklund, 2011). Other sections informing on the gestation activities, industry and different types of experiences will be used as controls to measure the relationships and the impacts of business planning and innovation on the performance of nascent firms overtime. Results from two rounds of pre-testing informed the design of the instrument included in the main survey. The three waves of data are used to first test and compare the use of planning amongst nascent firms by their degrees of innovation and then to examine their impact on performance overtime through regression analyses. Results and Implications Three waves of data collection have been completed. Preliminary results show that on average, innovative firms are more likely to have a business plans than their low innovative counterpart. They are also most likely to update their plan suggesting a more continuous use of the plan over time than previously thought. Further analyses regarding the relationships between business planning, innovation and performance are undergoing. This paper is expected to contribute to the literature on business planning and innovation by measuring quantitatively their impact on nascent firms activities and performance at different stages of their development. In addition, this study will shed a new light on the business planning-performance relationship by disentangling plans, types of nascent firms regarding their innovation degres and their performance over time. Finally, we expect to increase the understanding of the venture creation process by analysing those questions on nascent firms from a large longitudinal sample of randomly selected ventures. We acknowledge the results from this study will be preliminary and will have to be interpreted with caution as the business planning-performance is not a straightforward relationship (Brinckmann et al., 2010). Meanwhile, we believe that this study is important to the field of entrepreneurship as it provides some much needed insights on the processes used by nascent firms during their creation and early operating stages.
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Hepatitis C, which was first identified in 1988, has become an important issue for public health as epidemiological and clinical evidence has emerged. These disciplines have highlighted the extent of infection and its medical consequences. Now, governments at both the state and federal levels are sifting through this evidence and are attempting to create structures to deal with the problem of hepatitis C. These structures have generally taken the form of expert committees and working parties organised from established medical, scientific and public health bodies...
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This document provides data for the case study presented in our recent earthwork planning papers. Some results are also provided in a graphical format using Excel.
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Increasingly, the effectiveness of the present system of taxation of international businesses is being questioned. The problem associated with the taxation of such businesses is twofold. A system of international taxation must be a fair and equitable system, distributing profits between the relevant jurisdictions and, in doing so, avoiding double taxation. At the same time, the prevention of fiscal evasion must be secured. In an attempt to achieve a fair and equitable system Australia adopts unilateral, bilateral and multilateral measures to avoid double taxation and restrict the avoidance of tax. The first step in ascertaining the international allocation of business income is to consider the taxation of business income according to domestic law, that is, the unilateral measures. The treatment of international business income under the Australian domestic law, that is, the Income Tax Assessment Act 1936 (Cth) and Income Tax Assessment Act 1997 (Cth), will depend on two concepts, first, whether the taxpayer is a resident of Australia and secondly, whether the income is sourced in Australia. After the taxation of business profits has been determined according to domestic law it is necessary to consider the applicability of the bilateral measures, that is, the Double Tax Agreements (DTAs) to which Australia is a party, as the DTAs will override the domestic law where there is any conflict. Australia is a party to 40 DTAs with another seven presently being negotiated. The preamble to Australia's DTAs provides that the purpose of such agreements is 'to conclude an Agreement for the avoidance of double taxation and the prevention of fiscal evasion with respect to taxes on income'. Both purposes, for different reasons, are equally important. It has been said that: The taxpayer hopes the treaty will prevent the double taxation of his income; the tax gatherer hopes the treaty will prevent fiscal evasion; and the politician just hopes. The first purpose, the avoidance of double taxation, is achieved through the provision of rules whereby the Contracting States agree to the classification of income and the allocation of that income to a particular State. In this sense DTAs do not allocate jurisdiction to tax but rather provide an arrangement whereby the States agree to restrict their substantive law. The restriction is either through the non-taxing of the income or via the provision of a tax credit.
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Purpose: Flat-detector, cone-beam computed tomography (CBCT) has enormous potential to improve the accuracy of treatment delivery in image-guided radiotherapy (IGRT). To assist radiotherapists in interpreting these images, we use a Bayesian statistical model to label each voxel according to its tissue type. Methods: The rich sources of prior information in IGRT are incorporated into a hidden Markov random field (MRF) model of the 3D image lattice. Tissue densities in the reference CT scan are estimated using inverse regression and then rescaled to approximate the corresponding CBCT intensity values. The treatment planning contours are combined with published studies of physiological variability to produce a spatial prior distribution for changes in the size, shape and position of the tumour volume and organs at risk (OAR). The voxel labels are estimated using the iterated conditional modes (ICM) algorithm. Results: The accuracy of the method has been evaluated using 27 CBCT scans of an electron density phantom (CIRS, Inc. model 062). The mean voxel-wise misclassification rate was 6.2%, with Dice similarity coefficient of 0.73 for liver, muscle, breast and adipose tissue. Conclusions: By incorporating prior information, we are able to successfully segment CBCT images. This could be a viable approach for automated, online image analysis in radiotherapy.
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Background: Random Breath Testing (RBT) is the main drink driving law enforcement tool used throughout Australia. International comparative research considers Australia to have the most successful RBT program compared to other countries in terms of crash reductions (Erke, Goldenbeld, & Vaa, 2009). This success is attributed to the programs high intensity (Erke et al., 2009). Our review of the extant literature suggests that there is no research evidence that indicates an optimal level of alcohol breath testing. That is, we suggest that no research exists to guide policy regarding whether or not there is a point at which alcohol related crashes reach a point of diminishing returns as a result of either saturated or targeted RBT testing. Aims: In this paper we first provide an examination of RBTs and alcohol related crashes across Australian jurisdictions. We then address the question of whether or not an optimal level of random breath testing exists by examining the relationship between the number of RBTs conducted and the occurrence of alcohol-related crashes over time, across all Australian states. Method: To examine the association between RBT rates and alcohol related crashes and to assess whether an optimal ratio of RBT tests per licenced drivers can be determined we draw on three administrative data sources form each jurisdiction. Where possible data collected spans January 1st 2000 to September 30th 2012. The RBT administrative dataset includes the number of Random Breath Tests (RBTs) conducted per month. The traffic crash administrative dataset contains aggregated monthly count of the number of traffic crashes where an individual’s recorded BAC reaches or exceeds 0.05g/ml of alcohol in blood. The licenced driver data were the monthly number of registered licenced drivers spanning January 2000 to December 2011. Results: The data highlights that the Australian story does not reflective of all States and territories. The stable RBT to licenced driver ratio in Queensland (of 1:1) suggests a stable rate of alcohol related crash data of 5.5 per 100,000 licenced drivers. Yet, in South Australia were a relative stable rate of RBT to licenced driver ratio of 1:2 is maintained the rate of alcohol related traffic crashes is substantially less at 3.7 per 100,000. We use joinpoint regression techniques and varying regression models to fit the data and compare the different patterns between jurisdictions. Discussion: The results of this study provide an updated review and evaluation of RBTs conducted in Australia and examines the association between RBTs and alcohol related traffic crashes. We also present an evidence base to guide policy decisions for RBT operations.
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The output harmonic quality of N series connected full-bridge dc-ac inverters is investigated. The inverters are pulse width modulated using a common reference signal but randomly phased carrier signals. Through analysis and simulation, probability distributions for inverter output harmonics and vector representations of N carrier phases are combined and assessed. It is concluded that a low total harmonic distortion is most likely to occur and will decrease further as N increases.
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Background Random Breath Testing (RBT) remains a central enforcement strategy to deter and apprehend drink drivers in Queensland (Australia). Despite this, there is little published research regarding the exact drink driving apprehension rates across the state as measured through RBT activities. Aims The aim of the current study was to examine the prevalence of apprehending drink drivers in urban versus rural areas. Methods The Queensland Police Service provided data relating to the number of RBT conducted and apprehensions for the period 1 January 2000 to 31 December 2011. Results In the period, 35,082,386 random breath tests (both mobile and stationary) were conducted in Queensland which resulted in 248,173 individuals being apprehended for drink driving offences. Overall drink driving apprehension rates appear to have decreased across time. Close examination of the data revealed that the highest proportion of drink driving apprehensions (when compared with RBT testing rates) was in the Northern and Far Northern regions of Queensland (e.g., rural areas). In contrast, the lowest proportions were observed within the two Brisbane metropolitan regions (e.g., urban areas). However, differences in enforcement styles across the urban and rural regions need to be considered. Discussion and conclusions The research presentation will further outline the major findings of the study in regards to maximising the efficiency of RBT operations both within urban and rural areas of Queensland, Australia.
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The Australian e-Health Research Centre (AEHRC) recently participated in the ShARe/CLEF eHealth Evaluation Lab Task 1. The goal of this task is to individuate mentions of disorders in free-text electronic health records and map disorders to SNOMED CT concepts in the UMLS metathesaurus. This paper details our participation to this ShARe/CLEF task. Our approaches are based on using the clinical natural language processing tool Metamap and Conditional Random Fields (CRF) to individuate mentions of disorders and then to map those to SNOMED CT concepts. Empirical results obtained on the 2013 ShARe/CLEF task highlight that our instance of Metamap (after ltering irrelevant semantic types), although achieving a high level of precision, is only able to identify a small amount of disorders (about 21% to 28%) from free-text health records. On the other hand, the addition of the CRF models allows for a much higher recall (57% to 79%) of disorders from free-text, without sensible detriment in precision. When evaluating the accuracy of the mapping of disorders to SNOMED CT concepts in the UMLS, we observe that the mapping obtained by our ltered instance of Metamap delivers state-of-the-art e ectiveness if only spans individuated by our system are considered (`relaxed' accuracy).