2593409
Plugging a scalable authentication framework into Shibboleth
In a VO (virtual organization) environment where services are provided and shared by dissimilar organizations from different administrative domains and are protected with dissimilar security policies and measures, there is a need for a flexible authentication framework that supports the use of various authentication tokens. The authentication strengths derived from these tokens should be fed into an access control decision making process. This paper reports our ongoing efforts in designing and implementing such a framework to facilitate multi-level and multi-factor authentication and authentication strength linked fine-grained access control in Shibboleth. The proof-of-concept prototype using a Java smart card is reported.
1884872
A mobility monitoring based advance reservation protocol
Future wireless cellular networks will be Internet Protocol (IP) based. Users of wireless devices in these networks will expect to run real-time applications that require guarantees of Quality of Service (QoS). Such a user will expect the same seamless QoS that he would receive if he were running real-time applications on a wired network. Achieving seamless QoS in a mobile environment implies that a reservation should be re-established at the new Base Station (BS) before hand-over occurs. However, making these advance reservations is wasteful of valuable bandwidth in the wireless network. This paper proposes a protocol, called the Mobility Monitoring Based Advance Reservation Protocol (M²BARP), which aims to reduce the bandwidth overhead of making advance reservations. The protocol makes use of information about a Mobile Node's (MN) mobility to make a single advance reservation when the MN is about to hand-over. Unlike previous work, M²BARP takes advantage of overlapping cells to help to provide a more seamless QoS by reducing the number of calls dropped at hand-over
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.
1660866
A General Fuzzified CMAC Controller with Eligibility
This paper presents an online neural network controller. Cerebellar Model Articulation Controller (CMAC) is suitable to online control due to its fast learning speed. By integrating the CMAC address scheme with fuzzy logic concept, a general fuzzified CMAC (GFAC) is proposed. Then by incorporating the concept of eligibility into the GFAC, a GFAC controller with eligibility is presented, named FACE. A learning algorithm for the FACE is derived to tune the model parameters. To achieve online control, an efficient implementation of the proposed FACE method is presented. As an example, the proposed FACE is applied to a ship steering control system. The simulation results show that the ship course can be properly controlled under the disturbances of wave, wind and current.
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.
14935404
Levels of Authentication Assurance: an Investigation
The ES-LoA project, funded by the UK Joint Information Systems Committee (JISC) under its e- Infrastructure Security Programme, investigates current and future needs among UK research and education community for a more fine-grained authorisation scheme that would allow service providers to take into account of the levels of confidence in identifying a remote entity requesting for service access. Such a fine-grained authorisation scheme is attractive to service providers offering resources with varying levels of sensitivity and/or wishing to tailor their security protections based upon risk levels. Service providers may wish to restrict access to more sensitive resources only to those who have gone through a more stringent authentication process, or given the same remote entity, require the use of a stronger authentication token should the access request come from a more risky environment. In this way, the quality of an authentication instance, expressed as an authentication Level of Assurance (LoA), becomes one of the parameters used in access control decision making. This paper investigates the current worldwide efforts in defining LoA and identifies gaps in existing definitions when they are applied to a federated environment.
9362943
Finding shortest paths in large network systems
This paper describes a disk-based algorithm for finding shortest paths in a large network system. It employs a strategy of processing the network piece by piece and is based on new algorithms for graph partitioning and for finding shortest paths that overcome the problem of existing approaches. To show that it is scalable to large network systems and is adaptable to different computing environments, seven states in Tiger/Line files are extracted as test cases and are experimented on machines with different configurations. The running time for finding the shortest path depends primarily on the power of the underlying systems. Moreover, to run the algorithm optimally, the memory requirement is not large, even for a very large network system such as the road system in several states in Tiger/Line file. To evaluate its performance, New Mexico state road system is used as the test case, and is compared with Dijkstra's algorithm. The average running time of the proposed algorithm is, in the worst case, about two and a half times slower than that of Dijkstra's algorithm; provided that in Dijkstra's algorithm, the whole graph can be fit into main memory and is already loaded in advance. If the I/O time for loading the whole graph is counted, the proposed algorithm is faster in essentially all cases.
11989987
A comprehensive simulation study of SWAN QoS model in MANETs with proactive and reactive routing
In this paper, one of the QoS models for MANETs - SWAN is studied under varying conditions to provide both quantitative and qualitative assessments of the applicability of the model in different scenarios. Results and analysis from NS-2 based simulation indicate that (i) real-time (RT) applications in SWAN-enabled mobile ad hoc networks experience low and stable delays under various traffic and mobility environment at the expense of best-effort (BE) traffic, (ii) SWAN model works compatibly with proactive as well as reactive routing protocols. A careful choice of parameters is important to balance the throughput of the BE traffic and RT traffic and QoS provisions in MANETs.
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.
2090063
Primary-consistent soft-decision color demosaic for digital cameras
Bayer color mosaic sampling scheme is widely used in digital cameras. Given the resolution of CCD sensor arrays, the image quality of digital cameras using Bayer sampling mosaic largely depends on the performance of the color demosaic process. A common and serious weakness shared by all existing color demosaic algorithms is an inconsistency of sample interpolations in different primary color components, which is the culprit for the most objectionable color artifacts. To cure the problem we propose a primary-consistent color demosaic algorithm. The performance of this algorithm is further enhanced by a soft-decision sample interpolation scheme. Experiments demonstrate that the proposed framework of primary-consistent soft-decision color demosaic can significantly improve the image quality of digital cameras.
11164895
Primary-consistent soft-decision color demosaicking for digital cameras (patent pending)
Color mosaic sampling schemes are widely used in digital cameras. Given the resolution of CCD sensor arrays, the image quality of digital cameras using mosaic sampling largely depends on the performance of the color demosaicking process. A common problem with existing color demosaicking algorithms is an inconsistency of sample interpolations in different primary color channels, which is the cause of the most objectionable color artifacts. To cure the problem, we propose a new primary-consistent soft-decision framework (PCSD) of color demosaicking. In the PCSD framework, we make multiple estimates of a missing color sample under different hypotheses on edge or texture directions. The estimates are made via a primary consistent interpolation, meaning that all three primary components of a color are interpolated in the same direction. The final estimate of a color sample is obtained by testing different interpolation hypotheses in the reconstructed full-resolution color image and selecting the best via an optimal statistical decision or inference process. A concrete color demosaicking method of the PCSD framework is presented. This new method eliminates certain types of color artifacts of existing color demosaicking methods. Extensive experimental results demonstrate that the PCSD approach can significantly improve the image quality of digital cameras in both subjective and objective measures. In some instances, our gain over the competing methods can be as much as 7dB.