Advanced Materials Research Vols. 457-458

Abstract: An improved-immune-clonal-selection based spectrum assignment algorithm (IICSA) in cognitive radio networks is proposed, combing graph theory and immune optimization. It uses constraint satisfaction operation to make encoded antibody population satisfy constraints, and realizes the global optimization. The random-constraint satisfaction operator and fair-constraint satisfaction operator are designed to guarantee efficiency and fairness, respectively. Simulations are performed for performance comparison between the IICSA and the color-sensitive graph coloring algorithm. The results indicate that the proposed algorithm increases network utilization, and efficiently improves the fairness.

Abstract: A Doppler diversity transmitter for OFDM high-speed mobile communications based on fixed track is proposed. Because of fixed track, we can get the channel information and branches’ weights in advance, utilize the channel information do pre-equalization for every branch in transmitter. After modulation, branch outputs are individually frequency shifted, weighted and added together. Extensive simulations show that the proposed transmitter alters the statistics of the fading to improve BER significantly and better than the Doppler diversity receiver’s performance.

Abstract: A novel kind of high gravity device-rotating zigzag bed (RZB) was developed. The RZB is a kind of high efficiency gas-liquid contactor and a promising alternative in chemical process industries. However, because of the complexity of fluid flow inside the RZB, the flow experiments do not easily lead to the deeper understanding on the fluid dynamics in an RZB. This paper works with the CFD simulation of the process of RZB. Different gas flow velocities, rotating speed are comprehensively and systematically observed. The preliminary simulation results show that the models used to describe the RZB can give rise to better understanding of the flow in an RZB.

Abstract: In this paper, the features of electrical power steering (EPS) and semi-active suspension (SAS) systems have been carefully researched, and an integrated control strategy based on neural network theory was proposed to achieve the integrated control of EPS and SAS systems. In order to achieve the simulation of the integrated control strategy, a neural network controller of EPS and SAS systems was designed under MATLAB environment, and a passenger car virtual prototyping model including the EPS and SAS systems was established in vehicle dynamics simulation software SIMPACK. By ride comfort and handing stability simulation, the integrated control strategy was proved to be effective. The primary goal of this paper is to propose an effective and reliable integrated control strategy of EPS and SAS systems, and improve the ride comfort as well as handing stability of automobile.

Abstract: A variable step size Constant Modulus Algorithm (CMA) based on the gamma distribution is implemented as solutions to optimize the problem of blind equalization. The factor of step size in blind equalization algorithm is varied with gamma variable, in terms of the characteristics of which, the algorithm can search for the globe optimal equalizer weight vector. Simulation results indicate that the convergence rate and the steady Mean Square Errors (MSE) performances of the algorithm proposed are much better than conventional CMA and modified CMA blind equalization algorithms.

Abstract: Organizations increasingly are adopting information technology (IT) in order to automate their business processes to be competitive in marketplace. The greater evolving interdependence between information technology and business processes has created various opportunities for technologies and businesses. Therefore, co-evolutionary changes generate successes in business organizations. As evolution requirements either in business process or information technology can have an impact onto another, it is necessary to understand and manage the requirements in such a manner that consistency is maintained. This paper offers an insight of requirements analysis for co-evolution of business and IT. In this study we have used an observation of a bank in Saudi Arabia to assess the requirements of co-evolution of business and IT.

Abstract: The compilation of oil production project of oilfield is a huge and complex decisions making process, which involves multi-properties, multi-objectives problems. Considering the fact that the traditionally empirical methods already couldn’t meet the requirements such as scientific, advanced, and economic, we divide the decision making problems in oil production project into two categories: predictable decision making and evaluation decision making. Based on the characteristics of these two types of problems, we design the decision supporting system in oil production project of oilfield, which use B/S model, composing by model base, method base, database, and user interface. This system made full use of the history data of oilfield, improved the value of data, and greatly enriched the decision making methods for oil production project compilation. It also made the decisions more reasonable and improved the quality of project.

Abstract: An intrusion detection model based on biological immune principle and one-class classification technology is proposed. The one-class classification technology named support vector domain description (SVDD) is applied to the proposed model. Simple multi-dimension feature vectors of network packets are mapped into high dimension feature space. The description models of the antibody and the self set are constructed. The evolution process of antibodies is described with math language. The theoretical analysis shows that the proposed model can detect network attack effectively, and unknown network attacks can be detected.

Abstract: Recently, multi-carrier transmission schemes have been introduced into Code Division Multiple Access (CDMA) systems to gain advantages for high data rate transmission as well as security. Due to pseudorandom code there is no chance to Inter Symbol Interference (ISI). There are different techniques to mitigate multipath fading. One of the method is to transmit identical narrowband direct-sequence (DS) waveforms in parallel over a number of sub-channels using frequency diversity. Implementation this multi-carrier modulation technique in CDMA system is known as multi-carrier CDMA (MC-CDMA). In Rayleigh fading channel, due to multi-carrier modulation, when one subcarrier goes deep fade another subcarrier may remain safe. Therefore it combats multi-path fading and signal can be received in low bit error rate.

Abstract: Hydraulic fracture to oil well, creating fracture in the bottom stratum, making the crude oil flow to the bottom along the fracture are common stimulation treatment used in oil field. Controlling fracture height fracturing is controlling the extension of fracture within oil layer area, which is the key to success or failure of hydraulic fracturing. Especially, controlling fracture height to avoid pressing to wear the near water layer, which causes a sudden increase of oil water production, is particularly important to oil production. Fracture extension theory and field practice indicate that in controlling fracture height fracturing process, the fracture height extension is related with reservoir stress difference of oil layer and adjacent barrier on a certain scale of construction also it is related with the 8 parameters such as the rock Young's modulus, fracture toughness, Poisson's ratio, permeability, reservoir thickness, fracturing fluid viscosity and fluid loss coefficient and so on. This study introduces uncertain multi-attribute decision making method to the well needing controlling fracture height fracturing, takes expected minimum fracture height as the target, concentrates the 8 attribute values of oil well with OWA operator, obtains comprehensive attribute value, and sorts the expected oil well fracturing effect according to the size of comprehensive attribute value, then selects construction well according to the sort results. In this way, it not only solves the difficulty to accurately resolve fracture height of analytical method and problem of large calculation of numerical method, also provides a simple and practical method for live well selection. According to fracturing selection of Changqing oil field 5 wells and on-site application comparison of 2 wells, it is consistent with the prediction result.