14929484
An Auxiliary Ground Station Based Traffic Load Balancing Scheme for LEO Satellite Systems
In the Low Earth Orbit (LEO) satellite mobile communication system, traffic load in a spot beam fluctuates dramatically with a wide dynamic range due to the non-uniform geographical distribution of the traffic sources and the periodic satellite motion. The compromise between the utilization rate of valuable satellite channels and the blocking probability of a call causes higher proportion of channel idle time and cost of per connection. A new scheme based on auxiliary ground station (AGS) is proposed to solve this problem. The AGS is set to manage short distance calls. Simulation results illustrate that the proposed scheme balances the whole traffic load in LEO, improves the utilization rate of channels, and reduces the blocking probabilities of new calls and the dropping probabilities of handover calls. The cost of per connection is reduced at the same time.
3369144
Adaptive Multi-Channel MAC Protocol for Dense VANET with Directional Antennas
Directional antennas can increase the spatial reuse of the wireless channels and reach a higher antenna gain. This paper presents the design, implementation and simulation results of a multi-channel medium access control protocols for high density vehicular ad hoc networks using directional antennas with local beam tables. Simulation shows that our protocol has a higher throughput than the existing multi-channel protocols.
6306890
APPLE: A Novel P2P Based e-Learning Environment
With the rapid development of information technology, dramatic changes have been taken place in the fundamental ways that people acquire and disseminate knowledge. Various e-Learning systems have been designed to help people take full advantage of the benefit brought by the technology. The newly emerged Peer to Peer (P2P) and grid computing will serve as the key driven forces to bring revolutionary impact on the future society. This paper evaluates the potential contribution of the P2P and grid technology into the e-Learning system and introduces a novel P2P based e-Learning environment, called APPLE. With the help of Gnutella-like P2P network, APPLE provides live broadcasting services to share services of education resources. We build a virtual classroom service based on WSRF.NET, which exposes the service as a grid service that could be accessed by all the users among the grid.
694386
A Data Storage Mechanism for P2P VoD Based on Multi-channel Overlay
It is a big challenge to provide Video-on-Demand streaming services over Internet in a scalable way. Currently, many researchers use a single channel overlay to implement the scalability of on-demand streaming services. However, in a real application environment, various channels in a P2P VOD system have different popularities, which probably cause the imbalance of data storage-capability of the whole system. It results in a problem that a mass of unpopular channels' caching capability can not be used to satisfy the data requirements of the whole system. In order to solve the problem, this paper proposes a new data-storage mechanism, which constructs a multi-channel overlay to optimize the whole system's caching-capability and greatly improves unpopular channel's caching efficiency. The experimental results show that this mechanism can achieve significant effects.
8487669
An SMR based advance resource reservation scheme for combined mobility and QoS Provisioning
One of the major problems of deploying RSVP in the mobile environment is called the advance resource reservation problem. If an RSVP reservation path is reserved in advance in the subnet that a mobile node will visit, the mobile node can continue its QoS session smoothly when it hands over to that subnet. However, if too many network resources are used for advance reservation, new QoS sessions originating from that subnet will experience a higher probability of being blocked needlessly. In this paper, we propose a new advance resource reservation scheme that properly constrains the amount of advance reservations in a subnet and only allows the mobile nodes with large value of session-to-mobility ratio (SMR) to make advance reservation. We evaluate the proposed scheme and the results show that our scheme can effectively reduce both active and passive reservation blocking probabilities and achieves a better utilisation of the network resources, especially when the traffic intensity is high.
9428173
A Note on Quine's Principles of Quantification
In his Mathematical logic Quine characterizes the theorems of quantification theory by six principles:
14889815
Understanding the Session Durability in Peer-to-Peer Storage System
This paper emphasizes that instead of long-term availability and reliability, the short-term session durability analysis will greatly impact the design of the real large-scale Peer-to-Peer storage system. In this paper, we use a Markov chain to model the session durability, and then derive the session durability probability distribution. Subsequently, we show the difference between our analysis and the traditionalMean Time to Failure (MTTF) analysis, from which we conclude that the misuse of MTTF analysis will greatly mislead our understanding of the session durability. We further show the impact of session durability analysis on the real system design. To our best knowledge, this is the first time ever to discuss the effects of session durability in large-scale Peer-to-Peer storage system.
6971305
Video streaming over multi-hop wireless networks
In this paper, we considered the problem of transporting layered video over erroneous multi-hop wireless networks and proposed a distributed system. Our proposed distributed scheme is comprised of distributed control (DC), distributed buffer (DB) and distributed error control schemes. The DC scheme improves the efficiency of the network bandwidth usage and reduces the end-to-end delay of the streaming application. End-to-end delay jitter can be reduced by proper use of the DB nodes' buffer. Replacing the traditional EEC and ARQ with our distributed FEC and ARQ scheme reduces the error-protection overhead and ARQ delay and improves the wireless channel throughput. A layered video module is developed in GlomoSim 2.03 for video streaming application. We simulated our distributed scheme employing the layered video module in GlomoSim 2.03. Our simulation results confirm that QoS of streaming video over erroneous multi-hop wireless network can be improved using our proposed distributed scheme.
44314
A Novel Fault Diagnosis of Analog Circuit Algorithm Based on Incomplete Wavelet Packet Transform and Improved Balanced Binary-Tree SVMs
Aiming at to the characteristics of fault diagnosis of analog circuit with tolerances, noise, circuit nonlinearities and small sample set, this paper presents a novel algorithm for the existent problems based on incomplete wavelet packet transform for feature extraction and improved balanced binary-tree support vector machines (BBSVMs) for multi-classification. Firstly, analyzing characters of the optimal wavelet packet transform and the incomplete wavelet packet transform, the conclusion that the latter is perfect for fault diagnosis of analog circuit is obtained. Secondly, in order to perform multi-class classification, binary-tree-based SVMs has been studied. By introducing the separability measure that based on the space distribution of pattern classes, an improved balanced binary-tree structure is constructed. The proposed algorithm for analog circuits with tolerances and noise is implemented, and simulation results show us that compared with several existent fault diagnosis methods, the current algorithm has highest classification speed and higher classification accuracy, which make fault diagnosis of analogy circuit on-line promising.