Advanced Materials Research Vols. 433-440

Abstract: A novel moving-magnet linear motor was introduced which can produce high-frequency short stroke reciprocating motion, and it’s suitable to apply in linear compressor. The equivalent magnetic circuit model was established and the expression of driven force was given, then the impact the motor parameters made to motor performance was analyzed. The motor’s finite element model was established, the features of the air-gap magnetic field were studied, and the impact the length of the permanent magnet made to the motor stroke was analyzed. The foundation of the motor’s further optimization was laid by the results.

Abstract: The absolute stability problem of Lurie time-delays switched systems is investigated. All the subsystems are Lurie systems. Lyapunov functions is used to derive the sufficient conditions for the absolute stability of systems

Abstract: The biomass energy developmental strategy pattern is a basic logic frame that leads Heilongjiang state-owned forest area constructs core competitiveness, it had decided the basic mode and the way of Heilongjiang state-owned forest area long-term development, as well as the foundation of establishing the long-term competitive advantage in the biomass energy developing process. This article uses the super efficiency DEA analytic method to appraise the achievements of 40 forestry bureau development biomass energy in Heilongjiang state-owned forest area, finally indicated: choosing Heilongjiang characteristic biomass energy dual gradient developmental strategy pattern, and this pattern could coordinate the level of development of the high and low gradient region, prioritizing biomass energy source, advancing the coordinated development of energy, the economy, environment in Heilongjiang state-owned forest area, finally achieving the goal of sustainable development of the forestry.

Abstract: The combination with Geographical Information System (GIS) and Augment Reality (AR) technologies would become Augment Reality Geographical Information System (ARGIS). ARGIS is applied to urban transportation navigation and orientation so as to promote the development of outdoor AR systems, and also would break a new application field for GIS. In this essay, on the basis of introducing actuality, importance, basic constitution and application background of ARGIS, we emphasize on the application range, and method of application of ARGIS to urban transportation navigation and direction put forward the concept, the and the research framework for Augment Reality Geographical Information System (ARGIS).

Abstract: This paper presents a novel location algorithm for Ultra-Wideband (UWB) wireless communication based on Time Of Arrival (TOA) measurements. The traditional algorithm and mean value algorithm are compared with the proposed high probability algorithm in a three-dimensional (3D) indoor environment. The IEEE802.15.4a channel model is considered with Line-of-Sight (LOS) and Non-Line-Of-Sight (NLOS) propagation conditions, models CM1 and CM2, respectively. Performance results are presented which verify that the proposed algorithm can provide improved accuracy and robustness compared to other algorithms, particularly in poor channel environments.

Abstract: Chan algorithm is a closed form solution to the non-recursive equation set. This algorithm needs only a small amount of calculations but has a high degree of precision on positioning. It is valuable for academic reference. Firstly, it obtains the preliminary solution by using WLS (Weighted Least Squares) twice. Then, it uses the preliminary solution to linearise the nonlinear equation and finally makes the estimation of the position. The channel model can provide the model of indoor office environment ranging from 2 GHz to 10 GHz. Through the UWB (Ultra WideBand) positioning system of the channel model, the LOS(line-of-sight) environment can be simulated and TOA(Time-Of-Arrival) data measured by distance can also be obtained by sampling. However, small LOS errors included in the TOA data may lead to big ones in the positioning of 3D(three-dimensional) space and the precision of positioning may be undermined, when the data are directly applied to the Chan algorithm which is based on the TOA. In order to solve this issue, the TOA data obtained can be processed with MA(Moving Average) algorithm and the precision can be improved.

Abstract: For the growing importance of future emission restrictions and the expanding requirement for a better fuel economy, the internal combustion engines are forced to be improved for the high strengthening direction. However, the heat loads of the engine is increasing according to the increasing of engine speed and power density, hence, the cooling system is faced to more challenge. For the cooling system is one of the key system which has more effect on the engine efficiency, fuel economy, and exhaust heats; optimize the matching control cooling system becomes one of the key technology to improve the engine performance. In this paper, several overall schemes of the cooling system are analyzed and discussed, and then one design scheme is determined to the optimal for the current diesel engine. A whole engine system is established by the software GT-Power, and the cooling system in the engine system is established by GT-Cool based on the above optimal scheme. During the simulation, the influence on the heat dissipating capability brought by the control parameters, injection advance angle, power, and torque are investigated. At last, the requirement of the heat released under full conditions is analyzed, and the relationship of the fuel consumption and the control parameters is investigated.

Abstract: In this paper, robust output regulation problems of singular linear systems are studied. Under appropriate assumptions, it is given that the solvability of robust output regulation problems equals to a specifically row full rank matrix. Moreover, the methods for constructing the feedback regulator are discussed.

Abstract: The paper presents a framework of security region based dynamic security risk assessment of power transmission system. The application of practical dynamic security region (PDSR) in dynamic security risk assessment and the calculation steps of the dynamic security risk assessment are given in this paper. A model of risk assessment optimization which takes account of optimizing preventive and emergency control cost and contingency set decomposition is introduced. The effectiveness of this model has been proved by test results on the New England 10-generator 39-bus system.

Abstract: This study proposes a hybrid model for forecasting. The hybrid model is built on heuristic and weighted models of fuzzy time series. Compared to heuristic model, the hybrid model considers not only heuristic factors but also weighted factors. Hybrid model counts in more factors for dealing with forecasting problems to get a higher forecasting accuracy rate. The enrollment of University of Alabama is chosen as the forecasting targets. The empirical analyses show that the hybrid models provide better overall forecasting results than the previous models.