963 resultados para Balls (Parties)


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Bearing damage in modern inverter-fed AC drive systems is more common than in motors working with 50 or 60 Hz power supply. Fast switching transients and common mode voltage generated by a PWM inverter cause unwanted shaft voltage and resultant bearing currents. Parasitic capacitive coupling creates a path to discharge current in rotors and bearings. In order to analyze bearing current discharges and their effect on bearing damage under different conditions, calculation of the capacitive coupling between the outer and inner races is needed. During motor operation, the distances between the balls and races may change the capacitance values. Due to changing of the thickness and spatial distribution of the lubricating grease, this capacitance does not have a constant value and is known to change with speed and load. Thus, the resultant electric field between the races and balls varies with motor speed. The lubricating grease in the ball bearing cannot withstand high voltages and a short circuit through the lubricated grease can occur. At low speeds, because of gravity, balls and shaft voltage may shift down and the system (ball positions and shaft) will be asymmetric. In this study, two different asymmetric cases (asymmetric ball position, asymmetric shaft position) are analyzed and the results are compared with the symmetric case. The objective of this paper is to calculate the capacitive coupling and electric fields between the outer and inner races and the balls at different motor speeds in symmetrical and asymmetrical shaft and balls positions. The analysis is carried out using finite element simulations to determine the conditions which will increase the probability of high rates of bearing failure due to current discharges through the balls and races.

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A group key exchange (GKE) protocol allows a set of parties to agree upon a common secret session key over a public network. In this thesis, we focus on designing efficient GKE protocols using public key techniques and appropriately revising security models for GKE protocols. For the purpose of modelling and analysing the security of GKE protocols we apply the widely accepted computational complexity approach. The contributions of the thesis to the area of GKE protocols are manifold. We propose the first GKE protocol that requires only one round of communication and is proven secure in the standard model. Our protocol is generically constructed from a key encapsulation mechanism (KEM). We also suggest an efficient KEM from the literature, which satisfies the underlying security notion, to instantiate the generic protocol. We then concentrate on enhancing the security of one-round GKE protocols. A new model of security for forward secure GKE protocols is introduced and a generic one-round GKE protocol with forward security is then presented. The security of this protocol is also proven in the standard model. We also propose an efficient forward secure encryption scheme that can be used to instantiate the generic GKE protocol. Our next contributions are to the security models of GKE protocols. We observe that the analysis of GKE protocols has not been as extensive as that of two-party key exchange protocols. Particularly, the security attribute of key compromise impersonation (KCI) resilience has so far been ignored for GKE protocols. We model the security of GKE protocols addressing KCI attacks by both outsider and insider adversaries. We then show that a few existing protocols are not secure against KCI attacks. A new proof of security for an existing GKE protocol is given under the revised model assuming random oracles. Subsequently, we treat the security of GKE protocols in the universal composability (UC) framework. We present a new UC ideal functionality for GKE protocols capturing the security attribute of contributiveness. An existing protocol with minor revisions is then shown to realize our functionality in the random oracle model. Finally, we explore the possibility of constructing GKE protocols in the attribute-based setting. We introduce the concept of attribute-based group key exchange (AB-GKE). A security model for AB-GKE and a one-round AB-GKE protocol satisfying our security notion are presented. The protocol is generically constructed from a new cryptographic primitive called encapsulation policy attribute-based KEM (EP-AB-KEM), which we introduce in this thesis. We also present a new EP-AB-KEM with a proof of security assuming generic groups and random oracles. The EP-AB-KEM can be used to instantiate our generic AB-GKE protocol.

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The exchange of design models in the design and construction industry is evolving away from 2-dimensional computer-aided design (CAD) and paper towards semantically-rich 3-dimensional digital models. This approach, known as Building Information Modelling (BIM), is anticipated to become the primary means of information exchange between the various parties involved in construction projects. From a technical perspective, the domain represents an interesting study in model-based interoperability, since the models are large and complex, and the industry is one in which collaboration is a vital part of business. In this paper, we present our experiences with issues of model-based interoperability in exchanging building information models between various tools, and in implementing tools which consume BIM models, particularly using the industry standard IFC data modelling format. We report on the successes and challenges in these endeavours, as the industry endeavours to move further towards fully digitised information exchange.

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The problem of delays in the construction industry is a global phenomenon and the construction industry in Brunei Darussalam is no exception. The goal of all parties involved in construction projects – owners, contractors, engineers and consultants in either the public or private sector is to successfully complete the project on schedule, within planned budget, with the highest quality and in the safest manner. Construction projects are frequently influenced by either success factors that help project parties reach their goal as planned, or delay factors that stifle or postpone project completion. The purpose of this research is to identify success and delay factors which can help project parties reach their intended goals with greater efficiency. This research extracted seven of the most important success factors according to the literature and seven of the most important delay factors identified by project parties, and then examined correlations between them to determine which were the most influential in preventing project delays. This research uses a comprehensive literature review to design and conduct a survey to investigate success and delay factors and then obtain a consensus of expert opinion using the Delphi methodology to rank the most needed critical success factors for Brunei construction projects. A specific survey was distributed to owners, contractors and engineers to examine the most critical delay factors. A general survey was distributed to examine the correlation between the identified delay factors and the seven most important critical success factors selected. A consensus of expert opinion using the Delphi methodology was used to rank the most needed critical success factors for Brunei building construction. Data was collected and evaluated by statistical methods to identify the most significant causes of delay and to measure the strength and direction of the relationship between critical success factors and delay factors in order to examine project parties’ evaluation of projects’ critical success and delay factors, and to evaluate the influence of critical success factors on critical delay factors. A relative importance index has been used to determine the relative importance of the various causes of delays. A one and two-way analysis of variance (ANOVA) has been used to examine how the group or groups evaluated the influence of the critical success factors in avoiding or preventing each of the delay factors, and which success factors were perceived as most influential in avoiding or preventing critical delay factors. Finally the Delphi method, using consensus from an expert panel, was employed to identify the seven most critical success factors used to avoid the delay factors, and thereby improve project performance.

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Emotions play a central role in mediation as they help to define the scope and direction of a conflict. When a party to mediation expresses (and hence entrusts) their emotions to those present in a mediation, a mediator must do more than simply listen - they must attend to these emotions. Mediator empathy is an essential skill for communicating to a party that their feelings have been heard and understood, but it can lead mediators into trouble. Whilst there might exist a theoretical divide between the notions of empathy and sympathy, the very best characteristics of mediators (caring and compassionate nature) may see empathy and sympathy merge - resulting in challenges to mediator neutrality. This article first outlines the semantic difference between empathy and sympathy and the role that intrapsychic conflict can play in the convergence of these behavioural phenomena. It then defines emotional intelligence in the context of a mediation, suggesting that only the most emotionally intelligent mediators are able to emotionally connect with the parties, but maintain an impression of impartiality – the quality of remaining ‘attached yet detached’ to the process. It is argued that these emotionally intelligent mediators have the common qualities of strong self-awareness and emotional self-regulation.

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Immediate indefeasibility is the cornerstone of the Torrens system of land registration. However, when combined with the apparent ease in which forged mortgages become registered, the operation of this doctrine can come into question. This article seeks to argue that, rather than question indefeasibility, the focus should be on the verification of identity of parties to land transactions. Whilst no system can ever be infallible, it is suggested that by correctly imposing the responsibility for identity verification on the appropriate individual, the Torrens system can retain immediate indefeasibility as its paramount principle, yet achieve the optimum level of fairness in terms of allocation of responsibility and loss. With the dawn of a new era of electronic conveyancing about to begin, the framework suggested here provides a model for minimising the risks of forged mortgages and appropriately allocating the loss.

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Franchisor failure is one of the most problematic areas of the franchise relationship. It impacts negatively on landlords and other suppliers, but the contracting parties that are currently without legal rights to respond when a franchisor fails, and thus without consumer protection, are its franchisees. In this thesis I explore the current contractual, regulatory and commercial environment that franchisees inhabit, within the context of franchisor failure. I conclude that ex ante there are opportunities to level the playing field through consumer protection legislation. I also conclude that the task is not one solely for the consumer protection legislation; the problem should also be addressed ex post through the Corporations Act.

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AC motors are largely used in a wide range of modern systems, from household appliances to automated industry applications such as: ventilations systems, fans, pumps, conveyors and machine tool drives. Inverters are widely used in industrial and commercial applications due to the growing need for speed control in ASD systems. Fast switching transients and the common mode voltage, in interaction with parasitic capacitive couplings, may cause many unwanted problems in the ASD applications. These include shaft voltage and leakage currents. One of the inherent characteristics of Pulse Width Modulation (PWM) techniques is the generation of the common mode voltage, which is defined as the voltage between the electrical neutral of the inverter output and the ground. Shaft voltage can cause bearing currents when it exceeds the amount of breakdown voltage level of the thin lubricant film between the inner and outer rings of the bearing. This phenomenon is the main reason for early bearing failures. A rapid development in power switches technology has lead to a drastic decrement of switching rise and fall times. Because there is considerable capacitance between the stator windings and the frame, there can be a significant capacitive current (ground current escaping to earth through stray capacitors inside a motor) if the common mode voltage has high frequency components. This current leads to noises and Electromagnetic Interferences (EMI) issues in motor drive systems. These problems have been dealt with using a variety of methods which have been reported in the literature. However, cost and maintenance issues have prevented these methods from being widely accepted. Extra cost or rating of the inverter switches is usually the price to pay for such approaches. Thus, the determination of cost-effective techniques for shaft and common mode voltage reduction in ASD systems, with the focus on the first step of the design process, is the targeted scope of this thesis. An introduction to this research – including a description of the research problem, the literature review and an account of the research progress linking the research papers – is presented in Chapter 1. Electrical power generation from renewable energy sources, such as wind energy systems, has become a crucial issue because of environmental problems and a predicted future shortage of traditional energy sources. Thus, Chapter 2 focuses on the shaft voltage analysis of stator-fed induction generators (IG) and Doubly Fed Induction Generators DFIGs in wind turbine applications. This shaft voltage analysis includes: topologies, high frequency modelling, calculation and mitigation techniques. A back-to-back AC-DC-AC converter is investigated in terms of shaft voltage generation in a DFIG. Different topologies of LC filter placement are analysed in an effort to eliminate the shaft voltage. Different capacitive couplings exist in the motor/generator structure and any change in design parameters affects the capacitive couplings. Thus, an appropriate design for AC motors should lead to the smallest possible shaft voltage. Calculation of the shaft voltage based on different capacitive couplings, and an investigation of the effects of different design parameters are discussed in Chapter 3. This is achieved through 2-D and 3-D finite element simulation and experimental analysis. End-winding parameters of the motor are also effective factors in the calculation of the shaft voltage and have not been taken into account in previous reported studies. Calculation of the end-winding capacitances is rather complex because of the diversity of end winding shapes and the complexity of their geometry. A comprehensive analysis of these capacitances has been carried out with 3-D finite element simulations and experimental studies to determine their effective design parameters. These are documented in Chapter 4. Results of this analysis show that, by choosing appropriate design parameters, it is possible to decrease the shaft voltage and resultant bearing current in the primary stage of generator/motor design without using any additional active and passive filter-based techniques. The common mode voltage is defined by a switching pattern and, by using the appropriate pattern; the common mode voltage level can be controlled. Therefore, any PWM pattern which eliminates or minimizes the common mode voltage will be an effective shaft voltage reduction technique. Thus, common mode voltage reduction of a three-phase AC motor supplied with a single-phase diode rectifier is the focus of Chapter 5. The proposed strategy is mainly based on proper utilization of the zero vectors. Multilevel inverters are also used in ASD systems which have more voltage levels and switching states, and can provide more possibilities to reduce common mode voltage. A description of common mode voltage of multilevel inverters is investigated in Chapter 6. Chapter 7 investigates the elimination techniques of the shaft voltage in a DFIG based on the methods presented in the literature by the use of simulation results. However, it could be shown that every solution to reduce the shaft voltage in DFIG systems has its own characteristics, and these have to be taken into account in determining the most effective strategy. Calculation of the capacitive coupling and electric fields between the outer and inner races and the balls at different motor speeds in symmetrical and asymmetrical shaft and balls positions is discussed in Chapter 8. The analysis is carried out using finite element simulations to determine the conditions which will increase the probability of high rates of bearing failure due to current discharges through the balls and races.

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In a digital world, users’ Personally Identifiable Information (PII) is normally managed with a system called an Identity Management System (IMS). There are many types of IMSs. There are situations when two or more IMSs need to communicate with each other (such as when a service provider needs to obtain some identity information about a user from a trusted identity provider). There could be interoperability issues when communicating parties use different types of IMS. To facilitate interoperability between different IMSs, an Identity Meta System (IMetS) is normally used. An IMetS can, at least theoretically, join various types of IMSs to make them interoperable and give users the illusion that they are interacting with just one IMS. However, due to the complexity of an IMS, attempting to join various types of IMSs is a technically challenging task, let alone assessing how well an IMetS manages to integrate these IMSs. The first contribution of this thesis is the development of a generic IMS model called the Layered Identity Infrastructure Model (LIIM). Using this model, we develop a set of properties that an ideal IMetS should provide. This idealized form is then used as a benchmark to evaluate existing IMetSs. Different types of IMS provide varying levels of privacy protection support. Unfortunately, as observed by Jøsang et al (2007), there is insufficient privacy protection in many of the existing IMSs. In this thesis, we study and extend a type of privacy enhancing technology known as an Anonymous Credential System (ACS). In particular, we extend the ACS which is built on the cryptographic primitives proposed by Camenisch, Lysyanskaya, and Shoup. We call this system the Camenisch, Lysyanskaya, Shoup - Anonymous Credential System (CLS-ACS). The goal of CLS-ACS is to let users be as anonymous as possible. Unfortunately, CLS-ACS has problems, including (1) the concentration of power to a single entity - known as the Anonymity Revocation Manager (ARM) - who, if malicious, can trivially reveal a user’s PII (resulting in an illegal revocation of the user’s anonymity), and (2) poor performance due to the resource-intensive cryptographic operations required. The second and third contributions of this thesis are the proposal of two protocols that reduce the trust dependencies on the ARM during users’ anonymity revocation. Both protocols distribute trust from the ARM to a set of n referees (n > 1), resulting in a significant reduction of the probability of an anonymity revocation being performed illegally. The first protocol, called the User Centric Anonymity Revocation Protocol (UCARP), allows a user’s anonymity to be revoked in a user-centric manner (that is, the user is aware that his/her anonymity is about to be revoked). The second protocol, called the Anonymity Revocation Protocol with Re-encryption (ARPR), allows a user’s anonymity to be revoked by a service provider in an accountable manner (that is, there is a clear mechanism to determine which entity who can eventually learn - and possibly misuse - the identity of the user). The fourth contribution of this thesis is the proposal of a protocol called the Private Information Escrow bound to Multiple Conditions Protocol (PIEMCP). This protocol is designed to address the performance issue of CLS-ACS by applying the CLS-ACS in a federated single sign-on (FSSO) environment. Our analysis shows that PIEMCP can both reduce the amount of expensive modular exponentiation operations required and lower the risk of illegal revocation of users’ anonymity. Finally, the protocols proposed in this thesis are complex and need to be formally evaluated to ensure that their required security properties are satisfied. In this thesis, we use Coloured Petri nets (CPNs) and its corresponding state space analysis techniques. All of the protocols proposed in this thesis have been formally modeled and verified using these formal techniques. Therefore, the fifth contribution of this thesis is a demonstration of the applicability of CPN and its corresponding analysis techniques in modeling and verifying privacy enhancing protocols. To our knowledge, this is the first time that CPN has been comprehensively applied to model and verify privacy enhancing protocols. From our experience, we also propose several CPN modeling approaches, including complex cryptographic primitives (such as zero-knowledge proof protocol) modeling, attack parameterization, and others. The proposed approaches can be applied to other security protocols, not just privacy enhancing protocols.

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Peer-to-Patent Australia will initially run as a 12 month pilot project designed to test whether an open community of reviewers can effectively locate prior art that might not otherwise be located by the patent office during a typical examination. Patent applications will be made available for peer review for a period of 6 months and there will follow a 6 month period of joint qualitative and quantitative assessment of the pilot project by IP Australia and QUT. The objective of Peer-to-Patent Australia is to improve the patent examination process and the quality of issued patents by utilising the knowledge and skills of experts in the broader community. It is a way of linking the scientific and technical expertise of anyone with an Internet connection with the expertise of a patent examiner. That community participation consists of members of the public reviewing patent applications and contributing relevant prior art references and comments within a web-based forum. The aim is to bring to light prior art, particularly non-patent prior art, that might otherwise not be identified by patent examiners. The better the prior art resources a patent examiner has at his or her disposal, the more likely a patent application will be assessed properly in terms of novelty and inventive step. The role of Peer-to-Patent Australia in this regard is to act as both a facilitator of discussion and a collector of prior art submissions. Peer-to-Patent Australia collects relevant prior art references on behalf of the reviewing community and forwards that prior art to IP Australia. Section 27 of the Patents Act 1990 (Cth) allows for the Commissioner of Patents to receive submissions of prior art by third parties relevant to the novelty and inventiveness of a particular patent application.

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This paper raises the question of whether comparative national models of communications research can be developed, along the lines of Hallin and Mancini’s (2004) analysis of comparative media policy, or the work of Perraton and Clift (2004) on comparative national capitalisms. Taking consideration of communications research in Australia and New Zealand as its starting point, the paper will consider what are relevant variables in shaping an “intellectual milieu” for communications research in these countries, as compared to those of Europe, North America and Asia. Some possibly relevant variables include: • Type of media system (e.g. how significant is public service media?); • Political culture (e.g. are there significant left-of-centre political parties?); • Dominant intellectual traditions; • Level and types of research funding; • Overall structure of higher education system, and where communications sits within it. In considering whether such an exercise can or should be undertaken, we can also evaluate, as Hallin and Mancini do, the significance of potentially homogenizing forces. These would include globalization, new media technologies, and the rise of a global “audit culture”. The paper will raise these issues as questions that emerge as we consider, as Curran and Park (2000) and Thussu (2009) have proposed, what a “de-Westernized” media and communications research paradigm may look like.

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Sports sponsorship increasingly provides organisations with the opportunity to reach their target audiences in a manner that facilitates engagement and encourages relationship development. This paper provides an Australian perspective of the value of sports sponsorship using a case study of WOW Sight and Sound’s long-term sponsorship of the Brisbane Broncos rugby league team. The case study investigates WOW’s marketing objectives which centre generating brand awareness using sponsorship with the Brisbane Broncos as an integrated marketing communications tool. WOW believes that the integration of its sponsorship of the Broncos with the team’s total marketing plan is integral to its success. This integration requires the facilitation of two-way communications between WOW, its advertising agency, the Brisbane Broncos and customers to ensure that all parties’ needs are met.

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This book addresses the modern law relating to adoption. It comes at a time of fundamental change in adoption practice as, increasingly, Irish couples look outside the jurisdiction for the child that will make their family complete.---------- * Examines and explains the new regulatory framework and the law now governing domestic and intercountry adoption.---------- * Provides a guide to the changes outlined in the Adoption Bill 2008 which also consolidates the provisions of seven previous statutes and incorporates the Hague Convention into Irish statute law.---------- * Considers the responsibilities of the new Adoption Authority, and the roles of other administrative and legal bodies.---------- * Sets out the adoption process, explaining the complexities of intercountry adoption, giving consideration to the interface between adoption and children in care and dealing with the rights of the parties involved.

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The Government of Indonesia (GoI) increasingly relies on the private sector financing to build and operate infrastructures through public private partnership (PPP) schemes. However, PPP does not automatically provide the solution for the financing scheme due to value for money (VFM) issues. The procurement authority must show whether a PPP proposal is the optimal solution that provides best VFM outcome. The paper presents a literature review of comparing quantitative VFM methodology for PPP infrastructure project procurement in Indonesia and Australia. Public Sector Comparator (PSC) is used to assess the potential project VFM quantitatively in Australia. In Indonesia, the PSC has not been applied, where the PPP procurement authority tends to utilize a common project evaluation method that ignores the issues of risk. Unlike the conventional price bid evaluation, the PSC enables a financial comparison including costs/gains and risks. Since the construction of PSC is primarily on risk management approach, it can facilitate risk negotiation processes between the involved parties. The study indicates that the quantitative VFM methodology of PSC is potentially applicable in Indonesia for water supply sector. Various supporting regulations are available that emphasize the importance of VFM and risk management in infrastructure investment. However, the study also reveals a number of challenges that need to be anticipated, such as the need of a more comprehensive PPP policy at both central and local government level, a more specific legal instrument for bidding evaluation method and the issue of institutional capacity development in PPP Units at the local level.

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Delegation is a powerful mechanism to provide flexible and dynamic access control decisions. Delegation is particularly useful in federated environments where multiple systems, with their own security autonomy, are connected under one common federation. Although many delegation schemes have been studied, current models do not seriously take into account the issue of delegation commitment of the involved parties. In order to address this issue, this paper introduces a new mechanism to help parties involved in the delegation process to express commitment constraints, perform the commitments and track the committed actions. This mechanism looks at two different aspects: pre-delegation commitment and post-delegation commitment. In pre-delegation commitment, this mechanism enables the involved parties to express the delegation constraints and address those constraints. The post-delegation commitment phase enables those parties to inform the delegator and service providers how the commitments are conducted. This mechanism utilises a modified SAML assertion structure to support the proposed delegation and constraint approach.