Wendong Zhao

RR-LQD: A novel scheduling algorithm for CICQ switching fabrics

CICQ(Combined Input-Crosspoint Queued) is a switch fabric with buffers in crosspoints, which brings its nice distributed parallel scheduling property with no internal speedup required. In order to adjust to the nonuniform traffic in the network environment, a novel round-robin scheduling algorithm by using the longest queue detecting (RR-LQD) is proposed. The simulation results show that the RR-LQD can achieve 100% throughput and delay performance close to LQF-RR under various uniform and non-uniform traffics. In addition, the time complexity of RR-LQD is O(1) for hardware implementation. The implementation feasibility of RR-LQD is shown by an FPGA-based design in this paper.

An All-to-All-Broadcast Oriented MAC Protocol Using Directional Antennas in Ad Hoc Networks

In order to share information among all nodes, an all-to-all-broadcast scheme is needed for situation awareness networks. For this type of distributed sensor network, a directional antenna array, called multi-beam adaptive array (MBAA) is proposed to improve the transmission range and reject the interference. In this paper, an all-to-all-broadcast oriented MAC protocol is designed based on receiver-oriented multiple access (ROMA) protocol, which is an efficient MAC protocol exploiting the multi-beam forming capability of MBAA antennas but not designed for the information sharing. For all-to-all-broadcast scheme, the proposed protocol inserts two mini-slots for communication pairs to exchange control information, which helps to decrease the redundant data transmission and quicken the rate of information sharing. The performance of the proposed protocol is studied by the simulations. Compared with the original ROMA protocol, the proposed protocol shows a high performance in all-to-all-broadcast, which proves that the method can be an efficient way for similar MAC protocols to utilize all-to-all-broadcast scheme.

A fuzzy service matching algorithm based on Bloom filter

With the development of the Web service, enhancing the capabilities of the current Web service search engines with effective and efficient techniques for Web service retrieval and selection becomes an important issue. This paper presents a novel service matching degree assessment method based on Bloom filter. Facilitated by this method, an algorithm that supports service fuzzy matching has been proposed. The main idea of this algorithm is using Bloom filter to describe the service and request, and assessing the similarity of service and request by the similarity of Bloom filter vectors. Experimental and theoretical results show that this algorithm can support service fuzzy matching by simple algebraic operations on Bloom filter. The evaluation accuracy rate is beyond 95%.

Neighbor Discovery in Wireless Network with Double-Face Phased Array Radar

As one of the important steps in the process of self-organization of wireless ad hoc networks, neighbor discovery has substantial influence on the network performance. Especially in the modern warfare environment, the time consumption of neighbor discovery is very important for holding the battlefield situation. In this paper, we address the problem of neighbor discovery in ad hoc network with double-face phased array radar. And we take advantage of double-face phased array radar to improve the efficiency of neighbor discovery. Unlike former researches on single beam directional antenna, double beam directional antenna is introduced to our system. However, the direction of the antenna has been limited to two exclusive ranges due to the structure of double-face phased array radar. Obviously, the performance of the system which is in half duplex working mode can be better than the same one using single beam antenna. Thus we compare our system with the one using single beam antenna which is in full duplex mode. The experiential results show that the performance of neighbor discovery using double-face phased array radar in half duplex working mode is about 5 times better than the one using single beam directional antenna in full duplex working mode with the same algorithm.

An all-to-all broadcasting protocol using directional antennas in multi-hop wireless networks

In order to accelerate the information sharing, all-to-all broadcast needs more users to take part in the packet transmission at the same time. Directional antennas, which are capable of forming multiple beams, can provide improved spacial reuse on one hand. On the other hand, through analyzing the contention scenarios listed for multi-hop wireless networks in previous works, we find that the contention method of single transmission could be scheduled to improve the performance on all-to-all broadcast. As it is possible to receive the broadcast for all the receivers in the beam footprint of transmission antennas array, the proposed method activates the nulled beams of some receivers or silent nodes which are covered by the radiation beam to receive more data packets. In this paper, based on a unified algorithm for time division multiple access (TDMA), frequency division multiple access (FDMA) and code division multiple access (CDMA) channel assignment that is referred as the UxDMA algorithm [1], a protocol for all-to-all broadcast is designed to make full use of that contention scheduling method. And to exploit the multi-beam forming capability, multi-beam antenna array (MBAA) is employed by all nodes. Simulations show that the proposed protocol outperforms the original UxDMA algorithm on all-to-all broadcast with not only decreasing the delay and the number of data packet transmissions but also making a better use of the multi-beam antenna.

A Neighbor Discovery Algorithm in Network of Radar and Communication Integrated System

Networking Radar-Communication Integrated System (RCIS) promises an improved performance of radar and communication system platform by expanding scanning range and sharing information with each other. But equipping RCIS with directional antennas, in return, will worsen networks connectivity. In this paper, we aim to address the problem of neighbor discovery stage in networking process. Then, we are to present a directional neighbor discovery algorithm called scan based networking radar algorithm, or, SBA-RA. The difference between SBA-RA and previous researches which assume no prior knowledge of neighbors, is that SBA-RA makes full use of the approximate location information of neighbors obtained from RCIS platform to accelerate neighbor discovery. What is more, the performance of SBA-RA in RCIS is evaluated, and then compared with Scan-Based Algorithm (SBA) and Completed Random Algorithm (CRA) in terms of time consumption. And the experiments indicate SBA-RA outweighs the others. In the end, future possibilities to improve SBA-RA are discussed.

A Neighbor Discovering Algorithm in Radar-Based Ad Hoc Network Using Prior Information

Directional communication system aims to improve wireless performance with high-capacity and reliability by equipping system with directional antennas. Networking these directional communication systems can extend ranges of links and establish a wider ad hoc network. A key challenge in directionally networking is how to finish the neighbor discovering step as fast as possible with well-connectivity. In this paper, we address the problem of neighbor discovery with prior information and a new directional neighbor discovery algorithm called SBA-RA is presented while earlier algorithms operate blindly. SBA-RA can take full advantage of vague prior information of its neighbors got from scanning to find neighbors rather than at random as traditional algorithms do. Further more, we compare the performance of SBA-RA with SBA, CRA by their convergent time. The simulation results reveal that it is SBA-RA performs the best. In the end, we discuss several possible assumptions to improved SBA-RA in the future research.

BAPAWSC: A new dynamic web service composition algorithm in distributed environments

In order to overcome the shortcoming of performance bottleneck and single point of failure in centralized web service systems, a novel distributed dynamic service composition approach that based on Business Abstract Plan (BAP) has been proposed according to the distributed features of heterogeneous information systems. Using this approach, the BAP repository can be expanded automatically by the results of current composite plans, which can increase the response rate of service requests gradually. Simulation results demonstrate that the proposed approach can reduce the average response time of service queries and improve composition efficiency in distributed environments.

A hybrid semantic-based Battlefield Information Services matching algorithm

As the number of Battlefield Information Services (BISs) published on the registration center is growing up, matching techniques must be improved so as to retrieve more desirable services. But most of the proposed service matching algorithms have unsatisfied performance on the precision of service matching result because of the limitation caused by the roughly dividing of matching levels and neglecting the semantic asymmetry in similarity computation. In order to overcome such problems, combining logical reasoning and similarity computation, this paper proposed a hybird service matching algorithm for BISs, which makes matching levels unrestrictedly divided and the result more accurate. The algorithm can filter out the pseudo-matching services effectively and offer considerable saving in the battlefield bandwidth resources. Compared to other service matching algorithms, the experiment results showed that the approach could increase recall and precision ratio.

A Layered Recursive Construction Algorithm and a visualization method for concept lattice

As an efficient tool for data analysis, Formal Concept Analysis (FCA) is widely used in domains of software engineering and machine learning. The construction of concept lattice is the core step of FCA. A Layered Recursive Construction Algorithm (LRCA) is proposed in this paper. It creates direct child concepts for every concept and adopts the method of logical operation of attribute vectors to guarantee only direct child concepts can be produced. And it uses layered examining method to guarantee creating child concepts for each parent only once. A simulation experiment is done for performance evaluation. The experimental result shows that LRCA can greatly raise the processing ability by more than 6 times. In addition, a heuristic method is given for concept lattice visualization. It can automatically draw distinct and neat concept lattice diagram, and make the crosses of edges as few as possible.