436680
HMNR Scheme Based Dynamic Route Optimization to Support Network Mobility of Mobile Network
A lot of recent research has been focused on developing network mobility management to support the movement of a mobile network consisting of several mobile nodes. In the mobile ad-hoc network environment, network itself can be moved to another point. For the network mobility, the IETF NEMO working group proposed the basic support protocol for the network mobility to support the movement of a mobile network consisting of several mobile nodes. However, this protocol has been found to suffer from the so-called ‘dog-leg problem’, and despite alternative research efforts to solve this problem, there are still limitations in the efficiency for real time data transmission and intradomain communication. Accordingly, this paper proposes a new route optimization methodology that uses unidirectional tunneling and a tree-based intradomain routing mechanisms which can significantly reduce delay in both signaling and data transmission.
5710671
Distributed management architecture for multimedia conferencing using SIP
As various multimedia communication services are increasingly required by Internet users, several signaling protocols have been proposed for the efficient control of multimedia communication services. However, the model and architecture of multimedia conferencing which is currently being standardized by IETF is not suitable to meet the requirement for the management of large-scale multimedia conferencing service. In this paper, we have presented a management mechanism for distributed architecture of large scale multimedia conferencing service which is based on SIP. The high scalability is achieved by the coordinated distributed conference control and associated media processing without disruption of services. The SIP-based control mechanism for achieving the scalability has been designed in detail. Finally, the performance of the proposed architecture has been evaluated by simulation.
36360179
A Scalable Distributed Architecture for Multi-party Conferencing Using SIP
As various multimedia communication services are increasingly required by Internet users, several signaling protocols have been proposed for the efficient control of complex multimedia communication services. However, the model and architecture of multi-party conferencing which is currently being standardized by IETF has some limitation in scalability to meet the requirement for the management of large-scale multimedia conferencing service. In this article, we have presented a new scalable distributed architecture for the efficient management of large-scale multimedia conferencing service which is based on SIP. The high scalability is achieved by adding, deleting and modifying the multiple mixers and composing conference server network in a distributed way, in a real-time, and without disruption of services. The SIP-based control mechanism for achieving the scalability has been designed in detail. Finally, the performance of the proposed architecture has been evaluated by simulation.
57544361
Feasibility analysis of hard real-time periodic tasks
The problem of determining the feasibility of hard real-time periodic tasks is known to be co-NP-complete when there exists a task with relative deadline shorter than its period. Thus "Processor Demand Approach (PDA)" for synchronous task sets has been considered as a practical tool to solve the feasibility problem. PDA determines the feasibility of a task set by checking whether there exists a task whose deadline is missed by a certain time which is computed based on the characteristic of the task set. In this paper, we present a new method for feasibility test by combining PDA with the analysis methods for aperiodic scheduling. It is shown that the number of tests required of the new method to determine the feasibility is never greater than the smallest number of tests the existing algorithm requires. Although our method has pseudo-polynomial time complexity, experimental results show that the new method requires significantly less computation to determine feasibility.
23124676
Conditional variance estimation using stochastic learning algorithm
Aritificial neural networks may be used for a function approximator which includes not only deterministic but also probabilistic model. Conditional variance estimation using a neural network is a good example of probabilistic model approximation, because conditional variance, which is a function of input variable, is an important parameter to describe a Gaussian probabilistic model. The majority of learning algorithms are based on a concept of likelihood maximization or expectation maximization method. This article presents an alternative learning algorithm based on a different concept for a multilayer perceptron. The proposed variance learning algorithm can be regarded as a kind of modified delta rule, where delta is determined by an iterative estimation algorithm, which is also proposed in this article. The proposed learning algorithm has stochastic property because the delta is stochastically determined by the estimation algorithm. Relationships of delta to the transient and steady state of the learning process are also stochastic. First, the iterative variance estimation algorithm is explained. Second, the transient state behavior is investigated to have an insight into convergence and stability properties with respect to delta. Third, the steady state analysis is described to show the relationship of delta to steady state error bound. Theoretical analysis on steady state behavior produces analytic formula for steady state error bound of the variance learning algorithm in terms of the delta. Finally, multilayer perceptron using the proposed learning algorithm is simulated for the demonstration of variance estimation.
5446721
An efficient stream authentication scheme using tree chaining
Recently, the Internet is widely used for distributing stream data. To enable widespread commercial stream services, it is very important to provide data authentication and non-repudiation [1,4]. There are three issues to consider for authenticating live streams. First, for the sender, an authentication scheme must be efficient to support fast packet rates. Second, for receivers, the authentication scheme must assure a high verification probability in spite of a large packet loss (the verification probability is defined as a ratio of verifiable packets to received packets) [4]. Moreover, considering that lots of streams such as stock quote or traffic information have short lifetimes and that audio/video streams have to be played continuously, the verification of each received packet should be done within a short deadline. Third, communication overhead must be low. To achieve these goals, stream authentication schemes amortize each computation-
52817744
Fair Certified E-mail Protocols with Delivery Deadline Agreement
A certified e-mail system guarantees that a mail originator gets a receipt if and only if a recipient receives mail content. Unlike the previous schemes, the optimistic protocols that were recently proposed have some drawbacks: mail receiving can be delayed indefinitely or the originator can place the blame on the recipient for not having received the mail. In this paper, we point out some shortcomings in the optimistic protocols and improve them by introducing deadline agreement of mail delivery. We modelled the original protocols and the improved schemes by using ATS (Alternating Transition System) and verified them by using MOCHA, a model checker. MOCHA showed that the improved protocols do not have the shortcomings of the original schemes.
27314826
Rapid visualization of geometric information in a construction environment
A construction workspace is a dynamic environment that allows little time to obtain and update the graphical and image modeling information that is required in construction equipment operations. Comprehensive 3D models of the workspace require computationally intensive and expensive imaging processing, and usually take much longer than the ongoing construction operations permit. Rapid 3D positioning and modeling in construction can be used to plan, visualize and communicate operations before execution. They can also help to optimize equipment operations, significantly improve safety and enhance a remote operator's spatial perception of the workspace. This paper presents a rapid method, by combining human-assisted graphical workspace modeling with pre-stored CAD models and simple sensors (such as single-axis laser range-finders and remote video cameras), which can significantly reduce the modeling time while potentially increasing the modeling accuracy.