206522593
Revocation of privacy-enhanced public-key certificates
This paper presents a novel protocol for the revocation of privacy-enhanced/anonymous public-key certificates in relation to a protocol for anonymous public-key certificate issuing published previously. Not only can this certificate revocation protocol revoke an anonymous public-key certificate upon a request from its holder, but also automatically revoke any certificate issued directly or indirectly based on the certificate revoked, in an anonymous and accountable manner. In case the private key associated with an anonymous public-key certificate is suspected of having been compromised, the certificate holder can operate the protocol to easily revoke the compromised certificate together with its related ones so as to stop them being abused. The protocol is also assessed with regard to requirements such as accountability and anonymity.
14654466
A Purpose-Based Access Control Model
Achieving privacy preservation in a data-sharing computing environment is a challenging problem. The requirements for a privacy preserving data access policy should be formally specified in order to be able to establish consistency between the privacy policy and its purported implementation in practice. Previous work has shown that when specifying a privacy policy, the notion of purpose should be used as the basis for access control. A privacy policy should ensure that data can only be used for its intended purpose, and the access purpose should be compliant with the data's intended purpose. This paper presents a mechanism to specify privacy policy using VDM. The entities in the purpose-based access control model are specified, the invariants corresponding to the privacy requirements in privacy policy are specified, and the operations in the model and their proof obligations are defined and investigated.
42027884
New Approximation for Minimum-Weight Routing Backbone in Wireless Sensor Network
Our problem formulation is as follows. Given a weighted disk graph Gwhere the weight of edge represents the transmission energy consumption, we wish to determine a dominating tree Tof Gsuch that the total weight of edges in Tis minimized. To the best of our knowledge, this problem have not been addressed in the literature. Solving the dominating tree problem can yield a routing backbone for broadcast protocols since: (1) each node does not have to construct their own broadcast tree, (2) utilize the virtual backbone to reduce the message overhead, and (3) the weight of backbone is minimized. 
 
Our contributions to this problem is multi-fold: First, the paper is the first to study this problem, prove the hardness of this problem and propose an approximation framework. Second, we present a heuristic to approximate the solution with low time complexity. Third, a distributed algorithm is provided for practical implementation. Finally, we verify the effectiveness of our proposal through simulation.
17598350
Certified e-mail delivery with DSA receipts
In this paper we present two variant protocols DSA-CEMD1 and DSA-CEMD2 for certified e-mail delivery with DSA receipts. The protocols are based on a cryptographic primitive called Verifiable and Recoverable Encryption of a Signature (VRES) and are capable of achieving non-repudiation and strong fairness security properties. The novel design of the VRES primitive allows efficiency improvements in comparison with the related certified e-mail delivery protocols based on similar primitives. The protocols employ the services of an off-line and invisible trusted third party (TTP) only in case of dispute. In DSA-CEMD1 the content of the e-mail message is not revealed to the TTP during possible recovery and this is achieved at the cost of some additional cryptographic operations. In DSA-CEMD2 the confidentiality of the message is not protected from the TTP, but the protocol is slightly more efficient.
39605083
RSA-based Verifiable and Recoverable Encryption of Signatures and its application in certified e-mail delivery
This paper presents two variant protocols RSA-CEMDI and RDA-CEMD2 for certified e-mail delivery with RSA receipts. The protocols provide non-repudiation of origin and non-repudiation of receipt security services to protect communicating parties from each other's false denials that the e-mail message has been sent and received. The protocols also provide strong fairness to ensure that the recipient receives the e-mail if and only if the sender receives the receipt. Services of an off-time and transparent third party are invoked in the protocols only in exceptional circumstances, i.e.. when the communicating parties fail to complete the e-mail for receipt exchange due to a network failure or a party's misbehaviour. Protocol RSA-CEMDI also offers confidentiality protection for the e-mail message and the corresponding receipt from the third party, achieved at the cost of some additional computations. The protocols are based on a cryptographic primitive called Verifiable and Recoverable Encryption of a Signature (VRES). The novel design of the VRES allows efficiency improvements in comparison with the related certified e-mail delivery protocols based on similar primitives.
15488270
Segmentation of Spectrum Map for HFSWR Based on Feature Extraction
When targets fall in different types of clutter and noise background in High Frequency Surface Wave Radar (HFSWR), uniform detection algorithms always result in poor detection and tracking performances. To solve the problem, two methods are proposed in this paper by extracting the background features according to the probability distribution and the image characteristic of the spectrum map. The first method uses Parzen window for estimating probability density function and Kullback-Leibler convergence for evaluating the difference between the Azimuth-Range-Doppler cells in spectrum map which can be used to distinguish the homogenous detection background from the non-homogenous. The second method is proposed based on the image edge feature in multi-scale space. The real data results about HFSWR show that the proposed methods can not only identify noise/clutter but also help choose appropriate detection/tracking algorithms to improve performances in such complex environments.
445053
Prediction of Helix, Strand Segments from Primary Protein Sequences by a Set of Neural Networks
In prediction of secondary structure of proteins there are always some suspected segments. These suspected segments confuse people and lower the accuracy of prediction methods. To deal with this problem, a set of neural networks (NNs) are built based on helix, strand and coil segments selected from PDB. The test performance of these NNs on training data is perfect without surprise. However the prediction on test data is not good enough because the training data are lake of great representativeness. The results support the fact that closer neighbor vectors have the similar outputs of NNs. One can improve representativeness of training data without enlarging data scale as long as select less data from dense region and more from sparse region on condition that distribution of sample data has been known.
36024332
L-∞ constrained micronoise filtering for high-fidelity image compression
Imaging apparatus inevitably impose undesirable noises onto acquired images during real imaging process. Usually these noises are too faint to cause unpleasing visual effects, however, they degrade image fidelity and significantly lower the compression ratio of lossless coding. More baffling, in this case, there leaves little room for traditional noise filtering methods to work. This paper will introduce some of our efforts trying to weaken the effect of such Micro Noise during near-lossless compression. Experimental results on ISO test images and micro Gaussian noises demonstrate that with potentiality of filtering micro noise, an improved near-lossless coder can not only achieve obviously higher compression ratio but also provide better image fidelity (measured by mean squared error) than lossless coding.
23948133
Building Domain Ontology Based on Web Data and Generic Ontology
The automatic or semi-automatic construction of ontology has become a research topic of interest in recent years. This paper describes a mechanism for constructing domain specific ontologies automatically based on web data and generic ontology. Firstly, we employ the hierarchical agglomerative clustering(HAC) algorithm, clustering web pages hierarchically and resulting in a binary tree. Then an algorithm is proposed, which selectd from the binary tree the significative nodes as topics implying concepts of domain interests. Lastly, the Chinese generic ontology, HowNet, is introduced to evolve the topics (together with their hierarchical structures) into domain ontology. We experiment our method in the field of computer hardware based on web pages collected from Chinese BtoC web sites. An in-depth discussion on the experiment results is also given.
3386880
Statistical Learning Techniques for Costing XML Queries
Developing cost models for query optimization is significantly harder for XML queries than for traditional relational queries. The reason is that XML query operators are much more complex than relational operators such as table scans and joins. In this paper, we propose a new approach, called COMET, to modeling the cost of XML operators; to our knowledge, COMET is the first method ever proposed for addressing the XML query costing problem. As in relational cost estimation, COMET exploits a set of system catalog statistics that summarizes the XML data; the set of "simple path" statistics that we propose is new, and is well suited to the XML setting. Unlike the traditional approach, COMET uses a new statistical learning technique called "transform regression" instead of detailed analytical models to predict the overall cost. Besides rendering the cost estimation problem tractable for XML queries, COMET has the further advantage of enabling the query optimizer to be self-tuning, automatically adapting to changes over time in the query workload and in the system environment. We demonstrate COMET's feasibility by developing a cost model for the recently proposed XNAV navigational operator. Empirical studies with synthetic, benchmark, and real-world data sets show that COMET can quickly obtain accurate cost estimates for a variety of XML queries and data sets.
8279850
Analysis and Simulation Protocols Based on Slotted ALOHA for Plastic Optical Fiber Network
In this paper a novel multipriority reservation protocols for plastic optical fiber network is proposed. In conventional OCDMA system only allows finite units to transmit and access simultaneously according to the number of channels which be restricted by BER. To resolve this problem, a novel protocol based on slotted ALOHA is proposed in this paper. By using the reservation scheme and a distributed arbitration algorithm, channel collision and destination conflict can be avoided. The protocol can efficiently support the transmission of multimedia messages that require the different time-delay. The network throughput and average delay has been investigated by numerical analysis and simulation experiments. It is showed that the multipriority reservation protocol in this POF network is valid and efficient.