Agent-mediated non-repudiation protocols
Non-repudiation is a security service that provides cryptographic evidence to support the settlement of disputes in electronic commerce. In commercial transactions, an intermediary (or agent) might be involved to help transacting parties to conduct their business. Nevertheless, such an intermediary may not be fully trusted. In this paper, we propose agent-mediated non-repudiation protocols and analyze their security requirements. We first present a simple scenario with only one recipient, followed by a more complicated framework where multiple recipients are involved and collusion between them is possible. We also identify applications that could take advantage of these agent-mediated nonrepudiation protocols.

title: Securing digital signatures for non-repudiation
abstract: Dispute of transactions is a common problem that could jeopardise business. Hence non-repudiation services are essential in business transactions which provide evidence to enable dispute resolution. To be eligible as non-repudiation evidence, the digital signature on an electronic document should remain valid until its expiry date which is specified by some non-repudiation policy. The conventional approaches are either inefficient or insecure to achieve non-repudiation in electronic commerce. This article presents a practical scheme to secure digital signatures as non-repudiation evidence with an adjustable degree of risk.

title: Observations on Non-repudiation
abstract: This paper discusses non-repudiation services regarding the transfer of a message and classifies the roles of trusted third parties involved in non-repudiation services. We examine the selective receipt problem and the generation of time evidence, analyse the current state of the ISO/IEC 13888 drafts on non-repudiation mechanisms, and present a fair non-repudiation protocol including time evidence to promote the development of these drafts.

title: Non-Repudiation in Electronic Commerce
abstract: Electronic Commerce and Security. Repudiation and Dispute Resolution. Non-Repudiation and Network Security. Non-Repudiation in Message Handling Systems. Non-Repudiation in Electronic Payment Systems. Book Outline. Fundamentals of Non-Repudiation - Goals of Non-Repudiation. Non-Repudiation Services. Non-Repudiation Evidence. Roles of Trusted Third Parties. Phases of Non-Repudiation. Non-Repudiation Policy. Requirements for Non-Repudiation. Securing Digital Signatures for Non-Repudiation - Security Requirements on Digital Signatures. Time Stamps in Digital Signatures. Securing TTP's Digital Signatures. Time-Stamping Approach.  One-Way Sequential Link Approach.   Achieving Fair Non-Repudiation - Factors against Fair Non-Repudiation. Approaches for Fair Non-Repudiation.  Using Light-Weighted On-Line TTP.  Using Off-Line TTP without Timely Termination.  Using Off-Line TTP with Timely Termination.  Using In-Line TTP for Timely Delivery.  Related Work on Fair Non-Repudiation - Protocols Using In-Line TTP. Protocols Using On-Line TTP. Protocols Using Off-Line TTP. Protocols with Probablistic Fairness.  ISO's Non-Repudiation Mechanisms - Overview of ISO/IEC 13888. Mechanisms Using Symmetric Techniques. Mechanisms Using Asymmetric Techniques. Time-Stamping Evidence.  Case Studies - Non-Repudiation in Electronic Payment. Undeniable Billing in Mobile Communication.  Towards Formal Verification of Non-Repudiation - The SVO Logic. Formalization of Non-Repudiation. Verification of a Non-Repudiation Protocol.

title: Enforcing Trust in Pervasive Computing with Trusted Computing Technology
abstract: Pervasive computing as a concept holds the promise of simplifying daily life by integrating mobile devices and digital infrastructures into our physical world. These devices in a pervasive environment would establish dynamic ad-hoc networks to provide ubiquitous services. The open and dynamic characteristics of pervasive environments necessitate the requirement for some form of trust assumptions to be made. Trust in this context not only includes authentication, confidentiality and privacy but also includes the belief that the devices and smart environment behave as expected. In this paper, we propose a trust enforced pervasive computing environment using the primitives provided by a TPM (Trusted Platform Module). The application scenario shows how critical information infrastructure such as services and data can be protected. In this smart environment, a person carrying a device authenticates to the environment in order to utilize its services. In this context the device and the smart environment can also test and check each other's behaviors to better perform trust negotiation.

title: A fair non-repudiation protocol
abstract: A fair non-repudiation protocol should not give the sender of a message an advantage over the receiver, or vice versa. We present a fair non-repudiation protocol that requires a trusted third party but attempts to minimize its involvement in the execution of the protocol. We draw particular attention to the nonstandard use of encryption in our protocol and discuss some aspects of its formal verification.

title: Automatic detection of premature ventricular contraction using quantum neural networks
abstract: Premature ventricular contractions (PVCs) are ectopic heart beats originating from ventricular area. It is a common form of heart arrhythmia. Electrocardiogram (ECG) recordings have been widely used to assist cardiologists to diagnose the problem. In this paper, we study the automatic detection of PVC using a fuzzy artificial neural network named Quantum Neural Network (QNN). With the quantum neurons in the network, trained QNN can model the levels of uncertainty arising from complex classification problems. This fuzzy feature is expected to enhance the reliability of the algorithm, which is critical for the applications in the biomedical domain. Experiments were conducted on ECG records in the MIT-BIH Arrhythmia Database. Results showed consistently higher or same reliability of QNN on all the available records compared to the backpropagation network. QNN, however, has a relatively higher resource requirement for training.

title: Efficient exploitation of similar subexpressions for query processing
abstract: Complex queries often contain common or similar subexpressions, either within a single query or among multiple queries submitted as a batch. If so, query execution time can be improved by evaluating a common subexpression once and reusing the result in multiple places. However, current query optimizers do not recognize and exploit similar subexpressions, even within the same query.
 We present an efficient, scalable, and principled solution to this long-standing optimization problem. We introduce a light-weight and effective mechanism to detect potential sharing opportunities among expressions. Candidate covering subexpressions are constructed and optimization is resumed to determine which, if any, such subexpressions to include in the final query plan. The chosen subexpression(s) are computed only once and the results are reused to answer other parts of queries. Our solution automatically applies to optimization of query batches, nested queries, and maintenance of multiple materialized views. It is the first comprehensive solution covering all aspects of the problem: detection, construction, and cost-based optimization. Experiments on Microsoft SQL Server show significant performance improvements with minimal overhead.

title: An Overlay Subscription Network for Live Internet TV Broadcast
abstract: We propose a framework, called overlay subscription network (OSN), for live Internet TV broadcast, where a subscriber can choose to watch at any time. This framework allows the source server to incrementally build a topology graph that contains the network connections not only from the server to each subscriber, but also among the subscribers themselves. With such a topology graph in place, we consider efficient overlay multicast for scalable OSN services. We first show that idling nodes, which do not receive video data for their own playback, can actually be used for data forwarding to significantly reduce the cost of overlay multicast. In light of this observation, we then propose a novel overlay multicast technique that distinguishes itself from existing schemes with these three aspects. First, the proposed technique is centered on the topology graph and can take advantage of the actual network connections among the subscribing nodes. Second, the new scheme is able to find and incorporate appropriate idling nodes in multicast to reduce network traffic. Third, with our approach, a node can be used in multiple multicast trees for data forwarding to improve the overall system performance. We evaluate the performance of the proposed technique through simulation. Our extensive studies show that the proposed framework has the potential to enable the Internet, a vehicle up to date mainly for transferring text and image data, for large-scale and cost-effective TV broadcast

title: Toward automatic annotation of in situ mRNA expression patterns of drosophila embryos
abstract: The in situ mRNA hybridization gene expression pattern images of Drosophila melanogaster in the course of embryogenesis provide spatial-temporal information of the expression patterns of a target gene. This information is critical for understanding the roles of genes during the development of embryos. Currently, the annotation of these images is often done by manually assigning a subset of image ontology terms to the images. This approach is time consuming and depends heavily on the consistency of the experts. Alternatively, if the annotation process can be automated or semi-automated, efficiency and consistency are likely to be greatly enhanced. We formulate this task as a pattern classification problem, and present preliminary results. We consider both the template-based global matching and the multi-objective classification based on neural networks (e.g. multi-layer perceptron). We develop a method to combine them to optimize efficiency and accuracy. This method has been applied to the gene expression pattern image database generated by the Berkeley Drosophila Genome Project.

title: Data driven approach to designing minimum hamming distance polychotomizer
abstract: A polychotomous classifier assigns an observation to one of the K categories with K > = 3. Multiple binary classifiers (K = 2) such as the popular Support Vector Machines can be combined to achieve multi-class classification. Commonly used approaches include the one-vs-others scheme and the one-vs-one (pairwise coupling) scheme. While literature reported better performance from pairwise coupling than one-vs-others, the number of base learners required by pairwise coupling is quadratic in K. Alternatively, error correcting output codes (ECOC) provides a more general framework for designing polychotomizers. It associates each class with a codeword, which provides the capability to unify the traditional schemes. However, the design of an effective "coding matrix" remains an open problem. We study one kind of ECOC polychotomizer that decodes using minimum hamming distance. We propose a novel data-driven way to design the codewords based on inter-cluster distance. It provides a systematic way to extend the traditional schemes and construct effective polychotomizers. Experiments are conducted on synthetic data and real world applications including UCI repository problems and CENPARMI handwritten numerals. Experiments show that the proposed scheme can achieve competitive accuracy compared with both traditional schemes, and the number of base learners is typically much less than the requirement of the pairwise scheme.