204 resultados para magnetic exchange
Resumo:
The firm is faced with a decision concerning the nature of intra-organizational exchange relationships with internal human resources and the nature or inter-organizational exchange relationships with market firms. In both situations, the firm can develop an exchange that ranges from a discrete exchange to a relational exchange. Transaction Cost Economics (TCE) and the Resource Dependency View (RDV) represent alternative efficiency-based explanations fo the nature of the exchange relationship. The aim of the paper is to test these two theories in respect of air conditioning maintenance in retail centres. Multiple sources of information are genereated from case studies of Australian retail centres to test these theories in respoect of internalized operations management (concerning strategic aspects of air conditioning maintenance) and externalized planned routine air conditioning maintenance. The analysis of the data centres on pattern matching. It is concluded that the data supports TCE - on the basis of a development in TCE's contractual schema. Further research is suggested towards taking a pluralistic stance and developing a combined efficiency and power hypothesis - upon which Williamson has speculated. For practice, the conclusions also offer a timely cautionary note concerning the adoption of one approach in all exchange relationships.
Resumo:
We treat the security of group key exchange (GKE) in the universal composability (UC) framework. Analyzing GKE protocols in the UC framework naturally addresses attacks by malicious insiders. We define an ideal functionality for GKE that captures contributiveness in addition to other desired security goals. We show that an efficient two-round protocol securely realizes the proposed functionality in the random oracle model. As a result, we obtain the most efficient UC-secure contributory GKE protocol known.
Resumo:
A key exchange protocol allows a set of parties to agree upon a secret session key over a public network. Two-party key exchange (2PKE) protocols have been rigorously analyzed under various models considering different adversarial actions. However, the analysis of group key exchange (GKE) protocols has not been as extensive as that of 2PKE protocols. Particularly, the security attribute of key compromise impersonation (KCI) resilience has so far been ignored for the case of GKE protocols. We first 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 even against outsider KCI attacks. The attacks on these protocols demonstrate the necessity of considering KCI resilience for GKE protocols. Finally, we give a new proof of security for an existing GKE protocol under the revised model assuming random oracles.
Resumo:
Despite its importance in the development of competitive advantage, attempts to unify diverse classifications of business-to-business relational exchange have been largely unsuccessful. We used 18 semi-structured, in-depth interviews with managers from a wide range of industries to explain the business-to-business relational exchange construct. Analysis of the data revealed that business-to-business relational exchange comprises five key dimensions. These are communication, compatibility, commitment, trust and power symmetry. The research highlights the importance of personal interaction in business relationships and provided additional insights into the importance of affective commitment. In addition we reveal a number of negative consequences of affective commitment, which have been previously unexplored. A new conceptual model of business-to-business relational exchange is presented, which synthesises these findings and directs future research.
Resumo:
Introduction: 3.0 Tesla MRI offers the potential to quantify the volume fraction and structural texture of cancellous bone, along with quantification of marrow composition, in a single non-invasive examination. This study describes our preliminary investigations to identify parameters which describe cancellous bone structure including the relationships between texture and volume fraction.
Resumo:
We consider one-round key exchange protocols secure in the standard model. The security analysis uses the powerful security model of Canetti and Krawczyk and a natural extension of it to the ID-based setting. It is shown how KEMs can be used in a generic way to obtain two different protocol designs with progressively stronger security guarantees. A detailed analysis of the performance of the protocols is included; surprisingly, when instantiated with specific KEM constructions, the resulting protocols are competitive with the best previous schemes that have proofs only in the random oracle model.
Resumo:
We consider one-round key exchange protocols secure in the standard model. The security analysis uses the powerful security model of Canetti and Krawczyk and a natural extension of it to the ID-based setting. It is shown how KEMs can be used in a generic way to obtain two different protocol designs with progressively stronger security guarantees. A detailed analysis of the performance of the protocols is included; surprisingly, when instantiated with specific KEM constructions, the resulting protocols are competitive with the best previous schemes that have proofs only in the random oracle model.
Resumo:
We consider one-round key exchange protocols secure in the standard model. The security analysis uses the powerful security model of Canetti and Krawczyk and a natural extension of it to the ID-based setting. It is shown how KEMs can be used in a generic way to obtain two different protocol designs with progressively stronger security guarantees. A detailed analysis of the performance of the protocols is included; surprisingly, when instantiated with specific KEM constructions, the resulting protocols are competitive with the best previous schemes that have proofs only in the random oracle model.
Resumo:
Any cycle of production and exchange – be it economic, cultural or aesthetic – involves an element of risk. It involves uncertainty, unpredictability, and a potential for new insight and innovation (the boom) as well as blockages, crises and breakdown (the bust). In performance, the risks are plentiful – economic, political, social, physical and psychological. The risks people are willing to take depend on their position in the exchange (performer, producer, venue manager or spectator), and their aesthetic preferences. This paper considers the often uncertain, confronting or ‘risky’ moment of exchange between performer, spectator and culture in Live Art practices. Encompassing body art, autobiographical art, site-specific art and other sorts of performative intervention in the public sphere, Live Art eschews the artifice of theatre, breaking down barriers between art and life, artist and spectator, to speak back to the public sphere, and challenge assumptions about bodies, identities, memories, relationships and histories. In the process, Live Art frequently privileges an uncertain, confrontational or ‘risky’ mode of exchange between performer, spectator and culture, as a way of challenging power structures. This paper examines the moment of exchange in terms of risk, vulnerability, responsibility and ethics. Why the romance with ‘risky’ behaviours and exchanges? Who is really taking a risk? What risk? With whose permission (or lack thereof)? What potential does a ‘risky’ exchange hold to destabilise aesthetic, social or political norms? Where lies the fine line between subversive intervention in the public sphere and sheer self-indulgence? What are the social and ethical implications of a moment of exchange that puts bodies, beliefs or social boundaries at ‘risk’? In this paper, these questions are addressed with reference to historical and contemporary practices under the broadly defined banner of Live Art, from the early work of Abrovamic and Burden, through to contemporary Australian practitioners like Fiona McGregor.
Resumo:
We consider a new form of authenticated key exchange which we call multi-factor password-authenticated key exchange, where session establishment depends on successful authentication of multiple short secrets that are complementary in nature, such as a long-term password and a one-time response, allowing the client and server to be mutually assured of each other's identity without directly disclosing private information to the other party. Multi-factor authentication can provide an enhanced level of assurance in higher-security scenarios such as online banking, virtual private network access, and physical access because a multi-factor protocol is designed to remain secure even if all but one of the factors has been compromised. We introduce a security model for multi-factor password-authenticated key exchange protocols, propose an efficient and secure protocol called MFPAK, and provide a security argument to show that our protocol is secure in this model. Our security model is an extension of the Bellare-Pointcheval-Rogaway security model for password-authenticated key exchange and accommodates an arbitrary number of symmetric and asymmetric authentication factors.
Resumo:
The critical impact of innovation on national and the global economies has been discussed at length in the literature. Economic development requires the diffusion of innovations into markets. It has long been recognised that economic growth and development depends upon a constant stream of innovations. Governments have been keenly aware of the need to ensure this flow does not dry to a trickle and have introduced many and varied industry policies and interventions to assist in seeding, supporting and diffusing innovations. In Australia, as in many countries, Government support for the transfer of knowledge especially from publicly funded research has resulted in the creation of knowledge exchange intermediaries. These intermediaries are themselves service organisations, seeking innovative service offerings for their markets. The choice for most intermediaries is generally a dichotomous one, between market-pull and technology-push knowledge exchange programmes. In this article, we undertake a case analysis of one such innovative intermediary and its flagship programme. We then compare this case with other successful intermediaries in Europe. We put forward a research proposition that the design of intermediary programmes must match the service type they offer. That is, market-pull programmes require market-pull design, in close collaboration with industry, whereas technology programmes can be problem-solving innovations where demand is latent. The discussion reflects the need for an evolution in knowledge transfer policies and programmes beyond the first generation ushered in with the US Bayh-Dole Act (1980) and Stevenson-Wydler Act (1984). The data analysed is a case study comparison of market-pull and technology-push programmes, focusing on primary and secondary socio-economic benefits (using both Australian and international comparisons).