Applied Mechanics and Materials Vols. 121-126

Abstract: In this study, a simple model that describes frost formation over ground aircraft surfaces is presented. The model uses the data of the aircraft surface temperature, air temperature and air velocity to predict the frost thickness. The frost surface temperature and the frost thickness under different atmospheric conditions are investigated. The results indicate the frost thickness increases with the air velocity and the air temperature, decrease with the surface temperature. This model enables forecast of the frost formation over ground aircraft surface.

Abstract: Skin color detection is a hot research of computer vision, pattern identification and human-computer interaction. Skin region is one of the most important features to detect the face and hand pictures. For detecting the skin images effectively, a skin color classification technique that employs Bayesian decision with color statistics data has been presented. In this paper, we have provided the description, comparison and evaluation results of popular methods for skin modeling and detection. A Bayesian approach to skin color classification was presented. The statistics of skin color distribution were obtained in YCbCr color space. Using the Bayes decision rule for minimum cot, the amount of false detection and false dismissal could be controlled by adjusting the threshold value. The results showed that this approach could effectively identify skin color pixels and provide good coverage of all human races, and this technique is capable of segmenting the hands and face quite effectively. The algorithm allows the flexibility of incorporating additional techniques to enhance the results.

Abstract: This paper has proposed a remote water quality monitoring system based on ZigBee. The core of this system is the ZigBee wireless sensor network and GPRS network. Adopting the WSN tree routing structure and false alarm optimization algorithm, it can realize the remote detection and real-time monitoring of water quality. The clients can get access to the present and historical information of water quality conveniently，on which reasonable judgments can be formed to help with the management of water resources. The test in the West Trunk Canal of the Four-Lake Basin shows that the system has a high stability, high efficiency and great expandability.

Abstract: The Stress field of collinear periodic cracks in an infinite orthotropic composite plate subjected to the concentrated force is studied. The mechanical problem is turned into partial differential boundary value problem. The solution of partial differential equations can be obtained by the complex function methods, which contains unknown coefficients. Using undetermined coefficients method and with the help of boundary conditions, the partial differential boundary value problem is solved. The expressions for stress and displacements near crack tip are derived. Since the distribution of periodic cracks, the stress intensity factor is related to crack shape. Finally, a numerical example shows that the stress changes with the polar angle.

Abstract: This paper proves the feasibility of Rhino, a computer aided design software, in modeling design of sprinklers, through an analysis in the establishment of sprinklers’ chassis and an example of 3D modeling, and promotes a general method of shell modeling design of sprinklers based on Rhino.

Abstract: The product design theory and methods based on “the Scientific Outlook on Development” have been set up by our group in recent 10 years, The new progress concerning Research of product design theory and methods include: 1) QCTES was instead of IQCTES including six requirements of product design; 2) traditional design stages were replaced with four new stages including investigation, planning, implement and inspection; 3) green design was replaced with harmonious design; 4) traditional design method was replaced with deep-layer design method; 5) concept and connotation of product top-layer design were proposed; 6) more detailed contents of product synthesis design method were advanced. We got good effects to apply above product design methodology on many product designs recent years.

Abstract: Feature points can be used to match images. Candidate feature points are extracted through SIFT firstly. Then feature points are selected from candidate points through singular value decomposing. Distance between feature points sets is computed According to theory of invariability of feature points set, images are matched if the distance is less than a threshold. Experiment showed that this algorithm is available.

Abstract: BP network is the most widely used of the neural net work model, but there are many problems of slow convergence speed and easily getting into the local minimum in the conventional BP algorithm. For this, an improved algorithm is proposed. Momentum term is added, steepness factors are introduced and adaptive learning rate adjustment factor is added. In the Matlab platform simulations are carried out by each improvement methods on the same BP neural network. The results show that: Convergence of improved BP network is decreased from 1000 to 49 and the error is decreased from 10-2 to 10-6. The convergence speed has been significantly improved and the error has been decreased. Using the synthesis improvement method effect is obvious and it provides a good theoretical basis for the practical application.

Abstract: Texture and edge information are equally important to identification of most of natural images. To the problem of the existing integer order differential operators can’t extract texture information form the images, this study developed a fractional differential algorithm, which can extract texture and marginal information simultaneously, based on settlement of the drift problem of fractional differential operator. Experimental results showed that our algorithm can not only extract texture information but also extract more edge information than the traditional algorithms. And to the image with Gauss noise, our algorithm also have noise immunity.

Abstract: As stadiums have high energy consumption in architectural lighting and air conditioning, how to make full use of natural lighting and natural ventilation is the key to architectural energy conservation. To this end, many passive energy conservation measures have been taken into account in designing Multifunctional Stadium of Guangdong Pharmaceutical University. For instance, strip light windows with vertical shading have been installed on east and west facade, open external windows on south and north facade etc. Test result of the Stadium shows that the above-mentioned passive design methods are able to increase natural light intensity of the playing field and prevent glare, improve wind velocity of natural ventilation and comfort in spectator areas.