Multiple-input multiple-output (MIMO) system has very high spectrum efficiency. However, detection is a major challenge for the utilization of MIMO system. But even the fixed sphere decoding (FSD), which is known for its simplicity in calculation, requests too much computation in high order modulation and large number antenna system, especially for mobile battery-operated devices. In this paper, a reduced FSD algorithm is proposed to simplify the calculation complexity of the FSD while maintaining the performance at the same time. Simulation results show the effect of the proposed algorithm. Especially the results in a 4×4 64QAM system show that up to 81.2% calculation can be saved while the performance drop is less than 0.1dB when SNR=30.

With the increasing pressure on non-function attributes (security, safety and reliability) requirements of an operation system, high–confidence operation system is becoming more important. Formal verification is the only known way to guarantee that a system is free of programming errors. We research on formal verification of operation system kernel in system code level and take theorem proving and model checking as the main technical methods to resolve the key techniques of verifying operation system kernel in C code level. We present a case study to the verification of real-world C systems code derived from an implementation of μC/OS – II in the end.

TFRC protocol is suitable for video transmission in a wire network, and quality assessment is also essential in a video transmission system. In this paper, a real-time video transmission system based on TFRC protocol is proposed, and the evaluation model about the system is improved in the framework of Evalvid. It assesses the quality and efficiency of the video transmission according to the actual video file, and analyzes losses frame in different video types during transmission as well as the video quality in receiver. The results of simulation experiment in NS-2 show that when real-time video transmitted in wire network environment using this system, the receiver can get satisfactory video quality by reason of the TFRC protocol friendliness and the smoothness of sending rate. Based on the characteristic of high error rate in wireless network, the novel TCP friendly congestion control algorithm TFRC-JI proposed in our previous work [1] was adopted, which introduces the latency vibration to distinguish the link congestion from code error, thus different speed control mechanism is feedback to the transmitting end. Simulation experiment results indicated that compared with the traditional TFRC, the TFRC-JI suites well for real-time service transmission.

In this paper, a quality of service (QoS) multicast routing protocol in mobile ad hoc networks (MANETs) by using directional antennas has been presented. Many important applications, such as audio/video conferencing, require the quality of service guarantee. Directional antenna technology provides the capability for considerable increase in spatial reuse, which increases the efficiency of communication. This paper studies TDMA-based timeslot allocation and directional antennas, and presents an effective algorithm for calculating bandwidth of a multicast tree. We also propose a novel on-demand QoS multicasting routing algorithm in TDMA-based mobile ad hoc networks using directional antennas. The simulation result shows the performance of this QoS multicast routing algorithm in TDMA-based mobile ad hoc networks using directional antennas.

After analyzing the characteristics of Immunity Intrusion Detection System, by utilizing prominent characteristics of genetic algorithm and vaccine mechanism, a new hybird immunity intrusion detection model based on genetic algorithm and vaccine mechanism was established. The modeling process is described in detail, such as feature extraction of vaccine, genetic operates to memory detectors and the improvement for detection method. Via application vaccine mechanism into intrusion detection system, the new model has the function of misuse detection and anomaly detection simultaneously. In order to improve the detection matching efficiency, we also present a novel matching algorithm RBNDM. Finally, we evaluated our model using the KDD Cup 1999 Data set. The experiments show that this model can increase the true positive rate of the IDS.

Industrial control Ethernet networks are more important in connecting with equipments each other of enterprise comprehensive automation and integrating information. With the explosive growth of network techniques, the traditional control networks can no longer satisfy the security demands on network connectivity, data storage and information exchanges. New types of networks emerged in recent years in order to provide solutions for the increasing requirements on networked services. We propose a trust evaluation model for industrial control Ethernet network. Our study shows the importance and necessity of applying theoretical analyses to understand the complex characteristics of trusted industrial control Ethernet networks.

An improved dynamic probabilistic packet marking algorithm named IDPPM is presented, which not only can locate and attack a source rapidly and accurately, but also can reduce the marking overhead of routers near the attackers, which is its greatest contribution given by our technique. In contrast to previous work, the challenge of weakest node and weakest link is solved with the price of a little more numbers of packets to reconstruct the attack path. Theoretical analysis and NS2 simulation results in IPv4 and IPv6 testify that the approach is feasible and efficient respectively.

In this paper, the use of a uniform circular antenna arrays (UCA) for high resolution of two dimensional (2D) direction of arrivals (DOAs) estimation in wireless location system is investigated. Performance of 2D DOA estimation based on the real-valued unitary transformation MUSIC algorithm for UCA is presented, especially focusing on DOA estimation of multiple correlated signals. The determination of the number of incident signals on an antenna array is addressed in the condition of colored noise and coherent signal sources. Selected method for estimating the number of these sources is formulated based on the modified eigenvectors of the covariance matrix of the received signal at the antenna array. The calibration procedure is also presented for UCA especially. Simulation results are presented to confirm the performance analysis of algorithm, then the validations of Unitary Transformation MUSIC algorithm are performed based on the measurement data in a wireless location system.