Applied Mechanics and Materials Vols. 157-158

Abstract: In this paper, an object based cooperative spectrum sensing scheme with best relay (Pe-BRCS) is proposed, in which the best relay is selected by minimizing the probability of reporting error to improve the sensing performance. Numerical results show that, the Pe-BRCS can make the reduced reporting error probability and the improved sensing performance compared with the cooperative spectrum sensing scheme with best relay by maximizing the received SINR.

Abstract: An oscillator is designed for PWM controller chip. The resistance Rt and capacitance Ct for oscillator are located outside the chip to adjust the frequency expediently. The circuit is simulated by CADENCE Spectre, and the simulation results show that the frequency of the oscillator is 52.84KHz (at Vcc=15V), voltage stability is 0.4%. The layout is done based on the process flow and layout levels of bipolar 45V process provided by HUAYUE Microelectronics Company. The test results prove that the oscillator present in this paper meets the design requirements.

Abstract: Aiming to understand the asphalt granulation and separation processes in a new technique of solvent deasphalting, this work performs a detailed numerical study of the gas flow behaviors in a spray granulation tower with array nozzles. The influence of nozzle distances and jet angles on the fluid dynamics of the tower, especially on the double swirling flow, is investigated. The simulation results reveal many interesting phenomena, which include a flow consisting of two distinct regimes, a multistage flow development of jet array and a strong dependence of the velocity distribution on the nozzle arrangement.

Abstract: This paper is to simplify the keys on the control panel of the numerical control machine and use two keys to replace the traditional multi keys for cyclical selection of the working mode of the numerical control machine. The key signals are linked into the PLC by several signal wires on the control panel for the selection of the working mode, making the design of the panel structure and the signal circuit extremely complicated. This paper proposes the scheme in which there are only two keys “Working Mode +” and “Working Mode –” on the control panel, and works out a corresponding PLC program based on the FANUC system. The program deals with the cyclical selections of all the working modes and a quick entrance to the commonly used mode. The “Double Keys Scheme” reduces the number of keys on the panel, simplifies the control circuit, lowers the manufacturing cost, improves the stability and realizes the shortcut selection of the modes.

Abstract: According to the mode II fracture test results of the concrete of the double-edge notched specimens with four-point shear loading and half symmetrical loading, the relationship of the mode II fracture toughness of two type of concrete specimens are analyzed. Based on the numerical simulation, the stress field near the crack tip is analyzed by use of the finite element method, and the mode II fracture toughness of the two types of concrete specimens are calculated with the displacement extrapolation method, and the difference with the experimental results are studied. Because of the uniform stress of the specimen with half symmetric loading, and the shear stress in the fracture process zone is much larger than the first principal stress during the entire test process, while the phenomenon of opening and torsion of the surface of cracks may appeared at the four point shear loading conditions, which leads to the fracture process of the specimen is not always the mode II fracture of pure shear.

Abstract: Fast-flux service networks (FFSN) are new emerging phenomenon in the internet. Fast-flux networks use proxy networks of compromised machines to redirect and host scam service to achieve high availability. Such technique helps scam websites to avoid being traced and taken down by security professionals. In this paper, we use alternative decision tree algorithm to identify presence of fast-flux domains by analyzing only one address record (A-record) of DNS lookup, which achieves fast detection.

Abstract: Based on classical linear theory of shell, the deformation of functionally graded truncated conical shell subjected to transverse mechanical load as well as non-uniformly thermal load is studied. In the analysis, material properties of the shell are assumed to be temperature dependent, and graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. And then obtain the exact solution of the problem in terms of Bessel functions by using analytic method.

Abstract: Association rules can mine the relevant evidence of computer crime from the mass of data and association rules among data items, and further mine crime laws, trends and connections among different crimes. It provides police’s case detection and crime prevention with clues and criterions. This paper firstly analyzes the application of FP-Growth algorithms in computer crime forensics, points out the defect of FP-Growth algorithms that can’t timely find the latest crime and the serious crime, and then puts some improvements of the FP-Growth algorithms and tests it by carrying out experiments. Finally, it points out the future research aspect: extraction and correlation of multidimensional evidence.

Abstract: Compressed sensing (CS) is a new Compressed sensing (CS) is a new technique for simultaneous data sampling and compression. Inspired by recent theoretical advances in compressive sensing, we propose a new CS algorithm which takes the image complexity into consideration. Image will be divided into small blocks, and then acquisition is conducted in a block-by-block manner. Each block has independent measurement and recovery process. The extraordinary thought proposed is that we sufficiently take advantage of image characteristics in measurement process, which make our measurement more effective and efficient. Experimental results tell that our algorithm has better recovery performance than traditional method, and its calculation amount has greatly reduced.

Abstract: For vehicle routing optimization problem in the underground mine, a famous NP- Hard problem is put forward. This paper uses improved ant colony algorithm (ACA) to solve the problem. Basic ant colony algorithm (ACA) has many shortages, such as long searching time， slow convergence rate and easily limited to local optimal solution etc. The improved ant colony algorithm is proposed to overcome these shortcomings and improve its performance adaptively. In every iteration of the ant colony algorithm, adaptive evaporating coefficient is selected to control the convergence rate at first. And the power of this approach was demonstrated on a test case. The results derived from basic ACA and the improved ACA are compared and analyzed in the experiment. It proved that the improved ant colony algorithm is effective