140 resultados para Gauss sum

em Queensland University of Technology - ePrints Archive


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Principal Topic Although corporate entrepreneurship is of vital importance for long-term firm survival and growth (Zahra and Covin, 1995), researchers still struggle with understanding how to manage corporate entrepreneurship activities. Corporate entrepreneurship consists of three parts: innovation, venturing, and renewal processes (Guth and Ginsberg, 1990). Innovation refers to the development of new products, venturing to the creation of new businesses, and renewal to redefining existing businesses (Sharma, and Chrisman, 1999; Verbeke et al., 2007). Although there are many studies focusing on one of these aspects (cf. Burgelman, 1985; Huff et al., 1992), it is very difficult to compare the outcomes of these studies due to differences in contexts, measures, and methodologies. This is a significant lack in our understanding of CE, as firms engage in all three aspects of CE, making it important to compare managerial and organizational antecedents of innovation, venturing and renewal processes. Because factors that may enhance venturing activities may simultaneously inhibit renewal activities. The limited studies that did empirically compare the individual dimensions (cf. Zahra, 1996; Zahra et al., 2000; Yiu and Lau, 2008; Yiu et al., 2007) generally failed to provide a systematic explanation for potential different effects of organizational antecedents on innovation, venturing, and renewal. With this study we aim to investigate the different effects of structural separation and social capital on corporate entrepreneurship activities. The access to existing and the development of new knowledge has been deemed of critical importance in CE-activities (Floyd and Wooldridge, 1999; Covin and Miles, 2007; Katila and Ahuja, 2002). Developing new knowledge can be facilitated by structurally separating corporate entrepreneurial units from mainstream units (cf. Burgelman, 1983; Hill and Rothaermel, 2003; O'Reilly and Tushman, 2004). Existing knowledge and resources are available through networks of social relationships, defined as social capital (Nahapiet and Ghoshal, 1998; Yiu and Lau, 2008). Although social capital has primarily been studied at the organizational level, it might be equally important at top management level (Belliveau et al., 1996). However, little is known about the joint effects of structural separation and integrative mechanisms to provide access to social capital on corporate entrepreneurship. Could these integrative mechanisms for example connect the separated units to facilitate both knowledge creation and sharing? Do these effects differ for innovation, venturing, and renewal processes? Are the effects different for organizational versus top management team integration mechanisms? Corporate entrepreneurship activities have for example been suggested to take place at different levels. Whereas innovation is suggested to be a more bottom-up process, strategic renewal is a more top-down process (Floyd and Lane, 2000; Volberda et al., 2001). Corporate venturing is also a more bottom-up process, but due to the greater required resource commitments relative to innovation, it ventures need to be approved by top management (Burgelman, 1983). As such we will explore the following key research question in this paper: How do social capital and structural separation on organizational and TMT level differentially influence innovation, venturing, and renewal processes? Methodology/Key Propositions We investigated our hypotheses on a final sample of 240 companies in a variety of industries in the Netherlands. All our measures were validated in previous studies. We targeted a second respondent in each firm to reduce problems with single-rater data (James et al., 1984). We separated the measurement of the independent and the dependent variables in two surveys to create a one-year time lag and reduce potential common method bias (Podsakoff et al., 2003). Results and Implications Consistent with our hypotheses, our results show that configurations of structural separation and integrative mechanisms have different effects on the three aspects of corporate entrepreneurship. Innovation was affected by organizational level mechanisms, renewal by integrative mechanisms on top management team level and venturing by mechanisms on both levels. Surprisingly, our results indicated that integrative mechanisms on top management team level had negative effects on corporate entrepreneurship activities. We believe this paper makes two significant contributions. First, we provide more insight in what the effects of ambidextrous organizational forms (i.e. combinations of differentiation and integration mechanisms) are on venturing, innovation and renewal processes. Our findings show that more valuable insights can be gained by comparing the individual parts of corporate entrepreneurship instead of focusing on the whole. Second, we deliver insights in how management can create a facilitative organizational context for these corporate entrepreneurship activities.

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In an automotive environment, the performance of a speech recognition system is affected by environmental noise if the speech signal is acquired directly from a microphone. Speech enhancement techniques are therefore necessary to improve the speech recognition performance. In this paper, a field-programmable gate array (FPGA) implementation of dual-microphone delay-and-sum beamforming (DASB) for speech enhancement is presented. As the first step towards a cost-effective solution, the implementation described in this paper uses a relatively high-end FPGA device to facilitate the verification of various design strategies and parameters. Experimental results show that the proposed design can produce output waveforms close to those generated by a theoretical (floating-point) model with modest usage of FPGA resources. Speech recognition experiments are also conducted on enhanced in-car speech waveforms produced by the FPGA in order to compare recognition performance with the floating-point representation running on a PC.

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Volume measurements are useful in many branches of science and medicine. They are usually accomplished by acquiring a sequence of cross sectional images through the object using an appropriate scanning modality, for example x-ray computed tomography (CT), magnetic resonance (MR) or ultrasound (US). In the cases of CT and MR, a dividing cubes algorithm can be used to describe the surface as a triangle mesh. However, such algorithms are not suitable for US data, especially when the image sequence is multiplanar (as it usually is). This problem may be overcome by manually tracing regions of interest (ROIs) on the registered multiplanar images and connecting the points into a triangular mesh. In this paper we describe and evaluate a new discreet form of Gauss’ theorem which enables the calculation of the volume of any enclosed surface described by a triangular mesh. The volume is calculated by summing the vector product of the centroid, area and normal of each surface triangle. The algorithm was tested on computer-generated objects, US-scanned balloons, livers and kidneys and CT-scanned clay rocks. The results, expressed as the mean percentage difference ± one standard deviation were 1.2 ± 2.3, 5.5 ± 4.7, 3.0 ± 3.2 and −1.2 ± 3.2% for balloons, livers, kidneys and rocks respectively. The results compare favourably with other volume estimation methods such as planimetry and tetrahedral decomposition.

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The detection and correction of defects remains among the most time consuming and expensive aspects of software development. Extensive automated testing and code inspections may mitigate their effect, but some code fragments are necessarily more likely to be faulty than others, and automated identification of fault prone modules helps to focus testing and inspections, thus limiting wasted effort and potentially improving detection rates. However, software metrics data is often extremely noisy, with enormous imbalances in the size of the positive and negative classes. In this work, we present a new approach to predictive modelling of fault proneness in software modules, introducing a new feature representation to overcome some of these issues. This rank sum representation offers improved or at worst comparable performance to earlier approaches for standard data sets, and readily allows the user to choose an appropriate trade-off between precision and recall to optimise inspection effort to suit different testing environments. The method is evaluated using the NASA Metrics Data Program (MDP) data sets, and performance is compared with existing studies based on the Support Vector Machine (SVM) and Naïve Bayes (NB) Classifiers, and with our own comprehensive evaluation of these methods.

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The sum of k mins protocol was proposed by Hopper and Blum as a protocol for secure human identification. The goal of the protocol is to let an unaided human securely authenticate to a remote server. The main ingredient of the protocol is the sum of k mins problem. The difficulty of solving this problem determines the security of the protocol. In this paper, we show that the sum of k mins problem is NP-Complete and W[1]-Hard. This latter notion relates to fixed parameter intractability. We also discuss the use of the sum of k mins protocol in resource-constrained devices.

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Universal One-Way Hash Functions (UOWHFs) may be used in place of collision-resistant functions in many public-key cryptographic applications. At Asiacrypt 2004, Hong, Preneel and Lee introduced the stronger security notion of higher order UOWHFs to allow construction of long-input UOWHFs using the Merkle-Damgård domain extender. However, they did not provide any provably secure constructions for higher order UOWHFs. We show that the subset sum hash function is a kth order Universal One-Way Hash Function (hashing n bits to m < n bits) under the Subset Sum assumption for k = O(log m). Therefore we strengthen a previous result of Impagliazzo and Naor, who showed that the subset sum hash function is a UOWHF under the Subset Sum assumption. We believe our result is of theoretical interest; as far as we are aware, it is the first example of a natural and computationally efficient UOWHF which is also a provably secure higher order UOWHF under the same well-known cryptographic assumption, whereas this assumption does not seem sufficient to prove its collision-resistance. A consequence of our result is that one can apply the Merkle-Damgård extender to the subset sum compression function with ‘extension factor’ k+1, while losing (at most) about k bits of UOWHF security relative to the UOWHF security of the compression function. The method also leads to a saving of up to m log(k+1) bits in key length relative to the Shoup XOR-Mask domain extender applied to the subset sum compression function.

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Aspects of Keno modelling throughout the Australian states of Queensland, New South Wales and Victoria are discussed: the trivial Heads or Tails and the more interesting Keno Bonus, which leads to consideration of the subset sum problem. The most intricate structure is where Heads or Tails and Keno Bonus are combined, and here, the issue of independence arises. Closed expressions for expected return to player are presented in each case.

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Purpose of this paper This research aims to examine the effects of inadequate documentation to the cost management & tendering processes in Managing Contractor Contracts using Fixed Lump Sum as a benchmark. Design/methodology/approach A questionnaire survey was conducted with industry practitioners to solicit their views on documentation quality issues associated with the construction industry. This is followed by a series of semi-structured interviews with a purpose of validating survey findings. Findings and value The results showed that documentation quality remains a significant issue, contributing to the industries inefficiency and poor reputation. The level of satisfaction for individual attributes of documentation quality varies. Attributes that do appear to be affected by the choice of procurement method include coordination, build ability, efficiency, completeness and delivery time. Similarly the use and effectiveness of risk mitigation techniques appears to vary between the methods, based on a number of factors such as documentation completeness, early involvement, fast tracking etc. Originality/value of paper This research fills the gap of existing body of knowledge in terms of limited studies on the choice of a project procurement system has an influence on the documentation quality and the level of impact. Conclusions Ultimately research concludes that the entire project team including the client and designers should carefully consider the individual projects requirements and compare those to the trade-offs associated with documentation quality and the procurement method. While documentation quality is definitely an issue to be improved upon, by identifying the projects performance requirements a procurement method can be chosen to maximise the likelihood that those requirements will be met. This allows the aspects of documentation quality considered most important to the individual project to be managed appropriately.

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State-of-the-art image-set matching techniques typically implicitly model each image-set with a Gaussian distribution. Here, we propose to go beyond these representations and model image-sets as probability distribution functions (PDFs) using kernel density estimators. To compare and match image-sets, we exploit Csiszar´ f-divergences, which bear strong connections to the geodesic distance defined on the space of PDFs, i.e., the statistical manifold. Furthermore, we introduce valid positive definite kernels on the statistical manifold, which let us make use of more powerful classification schemes to match image-sets. Finally, we introduce a supervised dimensionality reduction technique that learns a latent space where f-divergences reflect the class labels of the data. Our experiments on diverse problems, such as video-based face recognition and dynamic texture classification, evidence the benefits of our approach over the state-of-the-art image-set matching methods.

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The decision as to which procurement system to adopt is a complex and challenging task for clients of construction projects. Despite a plethora of tools and techniques available for selecting a procurement method, clients are still uncertain about what method to adopt for a given construction project to achieve success. This paper examines ‘how and why’ procurement methods are selected by public sector clients in Queensland (QLD) and Western Australia (WA). Findings from workshops with senior managers in procurement selection revealed that traditional lump sum methods (TLS) are preferred even though alternative forms could be better suited for a given project. Participants of the workshops agreed that alternative procurement forms should be considered for projects but an embedded culture of uncertainty avoidance meant the selection of TLS methods. It was perceived that only a limited number of contractors operating in the marketplace have the resources and experience to deliver projects using the non-traditional methods.

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Purpose: The determination of the most appropriate procurement system for a capital works project is a challenging task for public sector clients considering the array of assessment criteria that are considered and the procurement methods that are available. This is particularly pertinent to the Western Australian public sector where they have had a propensity to use traditional lump sum as the default procurement solution despite knowing that the selection of an inappropriate procurement method may lead to cost and time overruns, claims, and disputes’ on projects. This paper presents a six step procurement method evaluation approach that requires public sector agencies to consider in detail an array of options so as to obtain value for money. Design/methodology/approach: A procurement evaluation approach is developed and is examined using a focus group of 12 participants comprising of a public sector client, project team and key stakeholders. The focus group was used to examine the developed approach in the context of a real-life capital works project. Findings: The procurement method evaluation approach was deemed to be pragmatic and enabled decision-makers to re-evaluate outcomes from previous steps in the process. All focus group participants stated the six step process enabled a recommendation that was grounded in reflection and detailed evaluation. Practical implications: The developed procurement approach has enabled the public sector client evaluate the way in which they view procurement method selection and examine how they obtain ‘value for money’. Originality/value: The six step procurement approach makes use of quantitative and qualitative techniques and is reliant on discourse and reflection in making a procurement method recommendation. Consequently, the approach enables public sector clients to account for the complexities often associated with procurement selection.

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Purpose: Choosing the appropriate procurement system for construction projects is a complex and challenging task for clients particularly when professional advice has not been sought. To assist with the decision making process, a range of procurement selection tools and techniques have been developed by both academic and industry bodies. Public sector clients in Western Australia (WA) remain uncertain about the pairing of procurement method to bespoke construction project and how this decision will ultimately impact upon project success. This paper examines ‘how and why’ a public sector agency selected particular procurement methods. · Methodology/Approach: An analysis of two focus group workshops (with 18 senior project and policy managers involved with procurement selection) is reported upon · Findings: The traditional lump sum (TLS) method is still the preferred procurement path even though alternative forms such as design and construct, public-private-partnerships could optimize the project outcome. Paradoxically, workshop participants agreed that alternative procurement forms should be considered, but an embedded culture of uncertainty avoidance invariably meant that TLS methods were selected. Senior managers felt that only a limited number of contractors have the resources and experience to deliver projects using the nontraditional methods considered. · Research limitations/implications: The research identifies a need to develop a framework that public sector clients can use to select an appropriate procurement method. A procurement framework should be able to guide the decision-maker rather than provide a prescriptive solution. Learning from previous experiences with regard to procurement selection will further provide public sector clients with knowledge about how to best deliver their projects.

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Co-production and strategic partnerships may generate valuable learning opportunities for firms to access to the knowledge and expertise of their partners. Such sharing and transfer of knowledge has become an increasingly common way for organising corporate finance and resources. However, not all collaborations result in a net positive experience for both partners. It can be a zero-sum game in which the partner learning the fastest dominates the relationship. In some cases, failure to gain access to partner knowledge results in unequal benefits accruing from such alliances. By examining the Singapore film industry from a learning perspective and taking into account particular forms of alliances, the study contributes to our understanding of the potential benefit and challenges of coproduction as a strategy for development.

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Prompt first aid can have considerable benefits. The Skills for Preventing Injury in Youth (SPIY) program aims to teach, in part, first aid skills along with additional injury prevention strategies. The approach to including first aid is both as an injury prevention strategy and a way in which to reduce the severity of injuries once they occur. This paper outlines an implementation trial of the SPIY program with particular emphasis on the delivery and implementation of first aid skills. SPIY demonstrated effectiveness with regard to first aid knowledge and as an injury prevention program. SPIY is taught in the Year 9 Health curriculum by HPE teachers. Students and teachers who undergo or deliver such training offer important perspectives about implementation. In addition independent observation of delivery provides further information about the program. The research aimed to examine teachers‟ and students‟ experiences of first aid activities within a school-based injury prevention and control program and identify key issues in delivery from independent observation of the program. Focus groups were held with 8 teachers who delivered, and 70 students who participated in the SPIY curriculum program. Results showed favourable reports on the delivery of first aid material however teachers noted challenges in delivering practical activities. In sum, first aid can be effectively implemented within the high school setting and both students and teachers identified multiple benefits and positive experiences after undertaking first aid training.