Design and Implementation of Hybrid Light and Microwave Switches Based on Wavelength Selective Switch for Future Satellite Networks

A hybrid switching node structure with light and microwave links is proposed, which is applicable to the future data relay satellite systems, aiming at the development trend of coexistence of light- link and microwave-link in the future. An experimental system for the light and microwave hybrid switching node based on wavelength selective optical switches (WSS) and optical transceiver modules, is established. It is shown by our experiment that this hybrid switching node can realize the dynamic bandwidth allocation and wavelength routing while the bit error rate of light link is less than 10?12, which provides a method for solving the hybrid switching problem of light-link and microwave-link on the future data relay satellite systems.

Design and Experimental Demonstration of Software Defined Space Optical Network (SDSON) Architecture Based on Cloud Platform

Space information network is used for real time acquiring, transmitting and processing the space information on the space platform, which provides significant communication services for communication, navigation positioning and science exploration. In this paper, the architecture of Software Defined Space Optical Network (SDSON) based on cloud platform is designed by means of Software Defined Optical Network (SDON) and cloud services. The new architecture combining centralized and distributed management-control mechanism is a multi-layer and multi-domain architecture with powerful computing and storage ability. Moreover, reliable service and unreliable service communication models employed in the space information network are proposed considering the characteristic of Disruption/Delay Tolerant Network (DTN). Finally, the functional verification and demonstration are performed on our optical experimental network platform.

Commonsense Reasoning and Nonmonotonic Aggregation Connectives on Fuzzy Sets

Commonsense representation and manipulation based on fuzzy logic is a new research field which handles the incompleteness, error-tolerability (allow exceptions) and uncertainty associated with commonsense knowledge. In this paper, we introduce a pair of nonmonotonic aggregation connectives on fuzzy sets-soft intersection and soft union, in the light of Zadeh’s fuzzy set theory. Some important features of the nonmonotonic connectives are also discussed.

Architecture and critical technologies of space information networks

Focusing on its main requirements and challenges and by analyzing the characteristics of different space platforms,an overall architecture for space information networks is proposed based on national strategic planning and the present development status of associated technologies.Furthermore,the core scientific problems that need to be solved are expounded.In addition,the primary considerations and a preliminary integrated demonstration environment for verification of key technologies are presented.

Optimizing CMT performance by joint predictions of bandwidth and RTT

CMT uses the stream control transmission protocol＇s（SCTPs） multihoming feature to distribute data across multiple end-to-end paths in a multihomed SCTP association. As the disparity of multipaths, it is facing a great challenge to solve the disorder of the received data packets. To lighten the reordering degree and then to improve the throughput performance, we need to estimate the real-time paths＇ bandwidth and round trip time（RTT） as exactly as possible. In this paper, we use the extended vector（ext-vec） Kalman filter（KF） to predict the available bandwidth and RTT of each path simultaneously. Based on this, we propose a predictive path selection algorithm for CMT in SCTP. To simulate and compare the algorithms＇ performance, two kinds of scenarios, bandwidth sensitive scenario and time and bandwidth sensitive scenario, are built and NS-2 is used. The simulation results show that the path selection algorithm can lessen the data packets disordering by correctly predicting each path＇s bandwidth and RTT in real time. Comparing the existing algorithms, the algorithm can converge more quickly and can improve the system total throughput in a certain extent in bandwidth sensitive scenario. To time and bandwidth sensitive scenario, it can greatly improve the convergence speed and total throughput.

A Fuzzy Proof Theory

Based on the first order predicate logic, in this paper, we present a new approach to generalizing the syn- tax of ordinary Horn clause rules to establish a fuzzy proof theory. First of all, each Horn clause rule is associ- ated with a numerical implication strength f. Therefore we obtain f-Horn clause rules. Secondly, Herbrand in- terpretations can be generalized to fuzzy subsets of the Herbrand base in the sense of Zadeh. As a result the proof theory for Horn clause rules can be developed in much the same way for f-Horm clause rules.

Rearrangeability of 7-stage 16 × 16 shuffle exchange networks

It has long been an outstanding conjecture that any(2^(n)×2^(n))-stage shuffle exchange network(Omega net-work)is rearrangeable for 2n 62n.Many researchers have failed to prove this conjecture,including a recent one established by Hasan.However,nobody has pointed out its fallacy.Therefore,as one of the objectives,this paper shall clarify this fact.Since the case of n 53 has been proven by many researchers[1,2],this paper uses a con-structive approach to prove that when n 54,the 7-stage 16616 shuffle exchange network is also rearrangeable.The paper also presents the model of a balanced tree to avoid internal conflict,the representation of permutations using a connection graph and loop graph,and the con-cepts of symmetry graph and identical transform.Based on graphic composition and bipartition,the permutations 16×16 are divided into five classes,with five assignment algorithms proposed.These algorithms are simpler,clearer and easier to program.The techniques used for n=4 may provide hints for the general case of n>4.