19257985
Proactive care-of address test for route optimization in FMIPv6
This paper proposes a practical scheme to run the care-of address test (part of the Return Routability test for Mobile IPv6 route optimization) in a proactive way in the context of the Fast Handovers for Mobile IPv6 (FMIPv6) protocol, so that the latency (normally one round-trip time between a mobile node and its correspondent node) caused by the care-of address test after movements can be removed or reduced. Proactive care-of address test can make the Return Rroutability protocol more suitable for delay sensitive applications especially when it is applied in conjunction with other Return Routability optimization schemes.
20173388
Spectral Decomposition Approach for Transient Analysis of Multi-Server Discrete-Time Queues
Abstract Discrete time queueing systems are extensively used in modeling the ATM environment at the cell level. This paper examines the transient behavior of a discrete time FCFS multiple server queue. For the arrival process we assume a general discrete time Markovian batch arrival process, where the batch size distribution of the arrivals in successive slots is governed by a finite state discrete time Markov chain. We show that once the spectral decomposition of the “probability generating matrix” of the arrival process is obtained, the complete solution in the transform domain may be given. Using the complex analysis technique and Cauchy's integral formula, we present an efficient numerical method for the numerical calculation of a few performance measures of interest, namely transient probability of queue being empty, and the mean of the queue length distribution. We also generalize our numerical method in the situations where the superposition of a number of independent arrival sources are fed to the queue. It is shown that the numerical complexity of obtaining the transient solution in this case can be substantially reduced by using the approach based on the Kronecker product. The finite buffer case is also analyzed.
5054397
The transient solution of time-dependent M/M/1 queues
The transient behavior of time-dependent M/M/1 queues is studied. The boundary probability function pi /sub 0/(t), which is the probability that the queue is empty at time t, is shown with analyticity arguments to satisfy a Volterra-type integral equation. The boundary integral equation is derived, and a numerical algorithm is used to solve the integral equation and to find the expected queue size from pi /sub 0/(t). The approach can be applied to many other types of time-dependent queues. Examples are given. >
24760638
Performance study of Markov modulated fluid flow models with priority traffic
The steady-state performance of generic high-speed queuing system with priority traffic is studied, using the Markov modulated fluid models. the focus is on systems with traffic partitioned into two priorities according to a splitting factor alpha , so that low priority traffic can be discarded when congestion occurs. The results are used to further study issues of congestion control with priority traffic. In particular, the expected values, waiting times, variances of the buffer contents, and tail distributions are evaluated. It is found that the waiting time is more sensitive to changes of alpha than the buffer contents. This shows that for time-constrained traffic, the priority assignment is important for properly balancing the tradeoff between packet loss and delays. This model can be considered as a direct extension of the fluid-flow model to include priorities.<<ETX>>
1453245
Recommendation over a Heterogeneous Social Network
With the Web content having been changed from homogeneity to heterogeneity, the recommendation becomes a more challenging issue. In this paper, we have investigated the recommendation problem on a general heterogeneous Web social network. We categorize the recommendation needs on it into two main scenarios: recommendation when a person is doing a search and recommendation when the person is browsing the information. We formalize the recommendation as a ranking problem over the heterogeneous network. Moreover, we propose using a random walk model to simultaneously ranking different types of objects and propose a pair-wise learning algorithm to learn the weight of each type of relationship in the model. Experimental results on two real-world data sets show that improvements can be obtained by comparing with the baseline methods.
15147551
Specification and Runtime Enforcement of Security Policies
The rapid growth in mobile and wireless communications entails serious problem of security. Formal methods can be used to help building secure mobile computing environment. Tabular expressions have proved to be useful and practical in formulating precise and complete documentation for computer systems. In this paper a framework for specification and runtime enforcement of security policies is proposed basing on the use of tabular expressions. A security policy can be specified with a tabular expression, and checking whether an application adheres to a given policy can be achieved by evaluating the tabular expression with respect to information intercepted at runtime. The advantages of our approach includes: (1) providing precise and readable specification of security policies; (2) developing a general policy enforcement engine rather than one policy enforcement engine for each security policy; (3)achieving low overheads by simplifying tabular expressions with static information of mobile code.
34224506
Exploiting Frame-to-Frame Coherence for Rendering Terrain Using Continuous LOD
It is the key issue of the terrain real-time rendering to reduce the time-spending for the level-of-detail. The concept of triangle live frame is introduced in this paper. Using this live frame, the algorithm reuses per-vertex visibility computation from previously displayed frames efficiently during continuous view-dependent level-of-detail visualizations. This algorithm decreases to a certain extent computing the distance from the viewpoint to vertex at each frame. Experimental results show that the algorithm reduces the time effectively to produce the LOD terrain.
12261164
Business Process Composition with QoS Optimization
One of the challenges in SOA is to provide an efficient and effective way to identify compatible Web service(s) and compose them into a service process that satisfies a user’s functional and non-functional needs. Quality of Service (QoS), like response time or throughput, might need to be optimized for the selected service process. This paper describes a system architecture and strategies Web services composition with QoS optimization. The strategies include a uniform cost backward search for optimizing response time and an improved greedy search for optimizing throughput.
28540271
Adaptive Training of a Kernel-Based Representative and Discriminative Nonlinear Classifier
Adaptive training of a classifier is necessary when feature selection and sparse representation are considered. Previously, we proposed a kernel-based nonlinear classifier for simultaneous representation and discrimination of pattern features. Its batch training has a closed-form solution. In this paper we implement an adaptive training algorithm using an incremental learning procedure that exactly retains the generalization ability of batch training. It naturally yields a sparse representation. The feasibility of the presented methods is illustrated by experimental results on handwritten digit classification.