Advanced Materials Research Vols. 219-220

Abstract: Currently, the issue of computer network security becomes more and more serious. This thesis takes the main factors that affect the computer network security as the breakthrough, and pays attention to the analysis and prevention of various measures that are not conducive to the normal operation of computer network. It also fully discusses the situations that affect the computer network security from different perspectives in order to take preventive measures, remove adverse factors in the embryonic stage and ensure the security management and effective operation of computer network. This thesis proposes solutions from seven aspects, namely security and encryption technology, firewall technology, network address translator technology, security kernel technology of operating system, technology of anti virus in computer network, network backup system and security management.

Abstract: In this paper, a traffic flow control scheme is presented. Wavelength division multiplexing (WDM) technology have significantly increased the transmission capacity of today’s transport networks, and played an extremely important role in high-speed network. Since high bandwidth wavelength channels will be filled up by many low-speed traffic streams, efficiently provisioning customer connections with such diverse bandwidth needs is a very important problem and is also known as the traffic-grooming problem. Traffic grooming is an extremely important issue for next-generation optical WDM networks.

Abstract: In this paper, we analyse the optical burst switched (OBS) network, discuss the OBS node architecture. In OBS network, to construct a good data structure is very important. The OBS incoming data are assembled into basic units, referred to as data bursts, which are then transported over the optical core network. As to the OBS signaling, it is performed out of band by control packets that carry information such as the length, the edge-node-destination address. OBS is a promising solution for the all-optical WDM networks.

Abstract: In spite of the growing focus on human-computer interaction design promoted by researchers and practitioners, there remains a large user population that is generally overlooked: people with physical disabilities. Most of HCI of disabled require wearing extra instruments, the HCI based on the camera is easy, efficient and comfortable. In this paper, we combined the applied and basic research, both drawing from psychological research and contributing new ideas to compare some HCI based on camera. We discuss user and products, and technology, highlighting challenges, open issues, and emerging applications for HCI based on camera of disabled.

Abstract: In recent years, optical network has made great progress. Optical networking architects were concerned with medium access control protocols for optical switching, the combination of wavelength conversion, and optimum forms of network. How to apply the simple high-speed transfer function of the optical network node to the IP network is an important issue in achieving an IP and optical integrated network. In this paper, we present a new node structure which has a new function. Adding new nodes to a optical network based on this new design, we can make a connection to different network. It is important to provide solutions for various requirements such as integrated optical network scalability and support for various types of networks in an optical network.

Abstract: Parameter optimization of PID control is always a hot spot in the research field of control, and control effect of PID depends on the parameter values: proportion, integral and differentiation. This paper puts forward a global best and local best PSO algorithm, which is an optimization strategy of PID, the result of this method making the system have small overshoot and short adjusting time. The optimization scheme of this paper will be used in the control of HVAC system. through simulation, it is shown that there is good effect, such as non-overshoot and short adjusting time. Compared with the traditional method, performance of this algorithm is well improved and optimized objective function is decreasing.

Abstract: Self-organized nanotube arrays were prepared by a facile two-electrode electrochemical anodization on pure Ti in a 0.5wt% NH₄F aqueous electrolyte. The surface morphology, structure, optical and photoelectrochemical behaviors of the nanotubular films were considered. The as-formed nanotubes are highly ordered with ~700nm in length and the average tube diameter is about 90nm. By annealing the initially amorphous films at different temperatures, the importance of the crystalline nature is confirmed. The photoelectrochemical properties are investigated and the highest photocurrent of 2.297 mA/cm² is obtained under AM1.5 100 mW/cm² illumination at 0.6 V (vs Ag/AgCl).

Abstract: Nanotubular films on the surface of Ti-2Al-1.5Mn (TC1) alloy were fabricated by electrochemical anodization technique in aqueous ammonium fluoride solutions at 20V for 3h. The photoelectrochemical activities of the nanotube arrays were investigated, as well as their phase, structure, composition and photoabsorption properties. The photo-absorption in the visible region and the photoelectrochemical response were improved obviously. It is attributed to the Mn ion doping of TiO₂ lattices. Furthermore, the resulted nanotube arrays are expected to have bright application prospects for solar utilization.

Abstract: The analysis of structure vibration signals is influenced by noise mixed in the signals. Independent component analysis (ICA) method is introduced to denoise the vibration signals in this paper. The representative algorithms: FastICA and JADE are told in detail. The algorithms are applied to separate steel structural vibration signals. The denoising performances in impulsive vibration signals generated by steel structure demonstrate the effectiveness and good robustness of ICA method.

Abstract: In this paper, an automatic segmentation system was developed for MRI brain tumor. Local region-based active contour models were suitable for heterogeneous features of brain MRI image. But the models are sensitive to initial contour, which generally requires manual setting. An automatic MRI brain tumor segmentation system were developed based on localized contour models, which can identify tumor-dominant slice, set initial contour automatically and segment tumor’s contours from all MRI slices autonomously. K-means clustering and grayscale analysis were combined to identify tumor-dominant slice. Multi-threshold algorithm with the aid of erosion and dilation operators was adopted to obtain an initial contour for the tumor-dominant slice. The segmentation contour from the local active contour models was applied as initial contours of two-side neighboring slices. MRI brain tumor data were applied to validate the automatic segmentation system.