18592986
Simulation Study of TCP Performance Over Mobile IPV4 and Mobile IPV6
Mobile IPv6 (MIPv6) is a protocol to deal with mobility for the next generation Internet (IPv6). However, the performance of MIPv6 has not yet been extensively investigated. Knowledge of how MIPv6 affects TCP performance, especially in comparison with MIPv4, can provide directions for further improvement. In this report, an intensive simulation study of TCP performance over MIPv4 and MIPv6 has been conducted. Simulation using the famous network simulator NS-2 will be used to highlight differences when TCP is used in hybrid wireless environment, over these two Mobile IP protocols. Initial simulation has shown a solid improvement in performance for MIPv6 when IPv6 Route Optimisation features are used. During the course of simulation, a consistent event causing dropped TCP throughput was identified. Out of order arrival of packets would occur when the mobile node initiated a handover. This out of order arrival invokes TCP congestion control falsely which reduces throughput. The difference in overall throughput of MIPv4 compared to MIPv6 is roughly proportional to the difference in packet size attributed to IPv6’s increased header size. Another contribution of this work is to provide modifications and new functions such as node processing time, to the NS-2 simulator to make such investigation possible. To the best of our knowledge, no similar publication has been reported.
38537514
A Biometric Encryption Approach Incorporating Fingerprint Indexing in Key Generation
This paper presents a new biometric encryption protocol in which encryption key is incorporated with fingerprint indexing. Based on the extended chaotic Baker map, the pixel permutation and gray level value substitution are performed to shuffle pixel positions in the original fingerprint images. The encryption key of the pixel permutation is generated by the combination of the random pixel distribution of a fingerprint imprint as well as features used for the fingerprint indexing. In addition to the advantage enjoyed by biometric keys over traditional password/PINs, the proposed biometric encryption approach is very efficient in identity identification within a large database due to the pre-filtering feature of the fingerprint indexing incorporated in the keys. This approach is applicable to the centralized matching scenario where fingerprints need to be encrypted before transmitted. Simulation results have validated the proposed schemes.
6719974
Intrusion Detection Based on Data Mining
15489348
A Gradient Based Weighted Averaging Method for Estimation of Fingerprint Orientation Fields
Estimation of orientation fields is an essential module in a fingerprint recognition system. Conventional gradient based approaches are popular but very sensitive to noise. In this paper, we propose a new implementation that is more resistant to noise. Our basic idea is to conduct redundant estimation over four overlapping neighborhoods for each target block. Following this idea, we devise a weighted averaging scheme operated on the base blocks directly. Thus, each block (including the target one) in the overlapping neighborhoods has different impact on estimation of the dominant orientation fields. Our preliminary experiment results suggest that the proposed weighted averaging algorithm is more robust against noise in comparison with other gradient based methods.
18760651
Modelling of SACK TCP and application to the HTTP file transfer environment
It is known that analytic modelling for TCP latency is a non trivial task. Recently, some significant progress has been made, such as the comprehensive result by Sikdar et al. However, models similar to these often rely on trial and error methods such as "data fitting". This can lead to a very limited scope for the resulting model and also large estimation error. In this paper, we propose improvements to Sikdar's SACK TCP model. A new delayed acknowledgement slow start model is developed that is analytically derived from the slow start algorithm which provides a novel mechanism to model the relationship between RTT and the delayed acknowledgement timer. We introduce a simple mechanism to include time taken to send an HTTP get request to broaden the scope of our SACK TCP model to Website file transfer. Simulation and live Internet experimentation has validated our scheme
86426
Gate Sizing for Cell-Library-Based Designs
With increasing time-to-market pressure and shortening semiconductor product cycles, more and more chips are being designed with library-based methodologies. In spite of this shift, the problem of discrete gate sizing has received significantly less attention than its continuous counterpart. On the other hand, cell sizes of many realistic libraries are sparse, for example, geometrically spaced, which makes the nearest rounding approach inapplicable as large timing violations may be introduced. Therefore, it is highly desirable to design an effective algorithm to handle this discrete gate-sizing problem. Such an algorithm is proposed in this paper. The algorithm is a continuous-solution-guided dynamic-programming-like approach. A set of novel techniques, such as locality-sensitive-hashing-based solution pruning, is also proposed to accelerate the algorithm. Our experimental results demonstrate that 1) the nearest rounding approach often leads to large timing violations and 2) compared to the well-known Coudert's approach, the new algorithm saves up to 21% in area cost while still satisfying the timing constraint.
4069319
Attribute Reduction Based on Granular Computing
Attribute reduction is a very important issue in data mining and machine learning. Granular computing is a new kind of soft computing theory. A novel method for encoding granules using bitmap technique is proposed in this paper. A new attribute reduction method based on granular computing is also developed with this encoding method. It is proved to be efficient.
612951
Exploring Multiple Design Topologies Using Genetic Programming And Bond Graphs
To realize design automation of dynamic systems, there are two major issues to be dealt with: open-topology generation of dynamic systems and simulation or analysis of those models. For the first issue, we exploit the strong topology exploration capability of genetic programming to create and evolve structures representing dynamic systems. With the help of ERCs (ephemeral random constants) in genetic programming, we can also evolve the sizing of dynamic system components along with the structures. The second issue, simulation and analysis of those system models, is made more complex when they represent mixed-energy-domain systems. We take advantage of bond graphs as a tool for multi- or mixed-domain modeling and simulation of dynamic systems. Because there are many considerations in dynamic system design that are not completely captured by a bond graph, we would like to generate multiple solutions, allowing the designer more latitude in choosing a model to implement. The approach in this paper is capable of providing a variety of design choices to the designer for further analysis, comparison and trade-off. The approach is shown to be efficient and effective in an example of open-ended real-world dynamic system design application, a printer re-design problem.
2207402
Bias properties of infinitesimal perturbation analysis for systems with parallel servers
Abstract Infinitesimal pertubation analysis (IPA) is a technique for estimating derivatives of performance measures from a single simulation of a stochastic discrete-event system, which might, for example, be modeling a computer/communication network or a manufacturing system. Such derivative estimates are useful in sensitivity analysis of the system and in optimizing—or at least improving—the performance of the system through gradient algorithms. However, it is well-known that IPA gives biased estimates for systems with multiple servers (channels or machines) in parallel when the server characteristics are not identical. In this paper, we investigate the seriousness of the bias both theoretically and experimentally. From our study, we believe the IPA estimator is relatively insensitive to small differences in the service time distributions of the servers. Specifially, we conjecture that for nearly-identical servers, the bias is proportional to the square of the difference between the means of the service time distributions. To support this conjecture, we present a tractable analytical example and investigate, via simulation experiments, more general systems.
1865144
Reducing clock skew variability via crosslinks
Increasingly significant variational effects present a great challenge for delivering desired clock skew reliably. Nontree clock network has been recognized as a promising approach to overcome the variation problem. Existing nontree clock routing methods are restricted to a few simple or regular structures, and often consume excessive amounts of wirelength. This paper suggests to construct a low-cost nontree clock network by inserting crosslinks in a given clock tree. The effects of the link insertion on clock skew variability are analyzed. Based on the analysis, this paper proposes two link insertion schemes that can quickly convert a clock tree to a nontree with significantly lower skew variability and very limited wirelength increase. In these schemes, the complicated nontree delay computation is circumvented. Further, they can be applied to the recently popular nonzero skew routing easily. The effectiveness of the proposed techniques has been validated through SPICE-based Monte Carlo simulations