IJITCS Vol. 3, No. 1, Feb. 2011
Cover page and Table of Contents: PDF (size: 129KB)
Highly scalable techniques for service discovery are key to the efficient use of Cloud resources, since the Cloud computing appears to be part of the mainstream computing in a few years. We embarked on a preliminary study on Cloud service discovery by adopting an unstructured P2P paradigm. We developed an efficient mechanism for routing of service requests by coupling a number of components: one-hop replication, semanticaware message routing, topology reorganization, and supernodes. A number of experiments were carried out that demonstrated the expected performance of the proposed P2P search scheme.[...] Read more.
As a kind of large-scale user-oriented dataintensive computing, cloud computing allows users to utilize on-demand computation, storage, data and services from around the world in a pay-as-you-go model. In cloud environment, applications need access to mass datasets that may each be replicated on different resources (or data centers). Mass data moving influences the execution efficiency of application to a large extent, while the economic cost of each replica itself can never be overlooked in such a model of business computing. Based on the above two considerations, how to select appropriate data centers for accessing replicas and creating a virtual machine(VM for short) to execute applications to make execution efficiency high and access cost low as far as possible simultaneously is a challenging and urgent problem. In this paper, a cost-aware resource selection model based on Weighted Set Covering Problem (WSCP) is proposed, according to the principle of spatial locality of data access. For the model, we apply a Weighted Greedy heuristic to produce an approximately optimal resource set for each task. Finally, verifies the validity of the model in simulation environment, and evaluate the performance of the algorithm presented. The result shows that WSCP-based heuristic can produce an approximately optimal solution in most cases to meet both execution efficiency and economic demands simultaneously, compared to other two strategies.[...] Read more.
To achieve good reconstruction speech quality in a very low bit rate speech codecs, an efficient dimension reduction quantization scheme for the linear spectrum pair (LSP) parameters is proposed based on compressed sensing (CS). In the encoder, the LSP parameters extracted from consecutive speech frames are shaped into a high dimensional vector, and then the dimension of the vector is reduced by CS to produce a low dimensional measurement vector, the measurements are quantized using the split vector quantizer. In the decoder, according to the quantized measurements, the original LSP vector is reconstructed by the orthogonal matching pursuit method. Experimental results show that the scheme is more efficient than that of conventional matrix quantization scheme, the average spectral distortion reduction of up to 0.23dB is achieved in the DFT transform domain. Moreover, in the approximate KLT transform domain, this scheme can obtain transparent quality at 5 bits/frame with drastic bits reduction compared to other methods.[...] Read more.
Based on the study of the existing PPS scheduling mechanism, we propose a novel PPS scheme for Differentiated QoS based on CICQ. The scheduling mechanism adopt in order queuing way to solve sequence preserving problem and set a small amount of buffer in the multiplexer to achieve differentiated QoS guarantee for different traffics which Ensure switch can provide effective support for different traffics in high-level. The simulation result indicates that the throughput of the mechanism can reach up to 99.97% at full load, and can according to the reservation bandwidth to allocate the bandwidth of output links, and ensure packets have an upper delay bound, and can balance the load to the exchange planes. Compared to the current mainstream PPS design, the mechanism is simple and easily implemented in hardware.[...] Read more.
Streaming media applications is currently limited by high bandwidth requirements. It is a challenging problem to provide the required quality of service (QoS) for the efficient transmission of video data under the varying network conditions such as the time-varying packet loss and fluctuating bandwidth. On Internet the most important part for streaming media transmission application is QoS control mechanism which including two kinds of QoS control method, based on end to end and network. A wireless streaming media forward platform based on the mixed quality-of-service (QoS) control system is introduced in this paper. The theoretical knowledge related to the quality of service and mixed quality of service control of the feasibility and characteristics are analyzed, and introduced a comprehensive quality of service in theory. This system combines network control and end to end quality of service control. The network of the system is optimized to support quality of service, using the underlying network devices, network bandwidth optimization, network structure adapted to meet the both ends of the quality of service. At both ends, from the delay, jitter, etc. are adjusted, by the addition of the timestamp and other information on the dynamic adjustment of the speed of data transmission. Through improving the control of two ends QoS and media streaming forward server, the video streaming from ships on the sea is transferred to the Internet by microwave and then linked to common Internet and mobile phone users through carrier networks(wired and wireless), which realized the real time supervision.[...] Read more.
This paper proposes a method of flame simulation based on Lagrange process and chemical composition, which was non-grid and the problems associated with there grids were overcome. The turbulence movement of flame was described by Lagrange process and chemical composition was added into flame simulation which increased the authenticity of flame. For real-time applications, this paper simplified the EMST model. GPU-based particle system combined with OpenGL VBO and PBO unique technology was used to accelerate finally, the speed of vertex and pixel data interaction between CPU and GPU increased two orders of magnitude, frame rate of rendering increased by 30%, which achieved fast dynamic flame real-time simulation. For further real-time applications, this paper presented a strategy to implement flame simulation with CUDA on GPU, which achieved a speed up to 2.5 times the previous implementation.[...] Read more.
This paper presents a indirect method of measuring flux characteristics based on DSP. By measuring current and voltage on a phase winding circuit and transfer them to PC by communication program, combined with the Simpson’s rule, the magnetization characteristics are obtained. The experimental instruments needed in this method are common, and the test platform is easy to be built, thus the expense is lowered in measurement of flux. The test indicates the measuring process is simple to implement, and the experimental results are accurate.[...] Read more.
Mobile Office Automation is a popular application on the mobile platform. However, the mobile platform has no enough security protection in front of the open system, such as internet. The document security problem in this application has become a hot topic. This paper proposed a new solution to this problem. The solution based on the trusted computing technology, which implements the platform security by hardware. The solution also includes the transparent encryption technology that means application could run independent to the security module and keep the consistency of user experience. The trusted mobile client platform architecture and security functions process of the mobile document protection system are detailed. Related work also been introduced; the security analysis shows the proposed solution could provide well security enhancement for document protection in mobile platform.[...] Read more.