Applied Mechanics and Materials Vols. 490-491

Abstract: This paper researched dynamic characteristics of 5-DOF scraper chain handling robot by finite element modal analysis. Firstly established the whole three-dimensional model with Solidworks, secondly, transferred it into the ANSYS finite element analysis software to analyze dynamic characteristics in two fixed work positions when it was grasping a scraper chain and carrying a scraper chain on a rail line. It was found the weak component which vibrated heavily was the big arm from the analysis of the top 5 order vibration mode. Then studied modal analysis of the big arm to obtain the its inherent frequency and vibration mode. Finally put forward some suggestions about the design of the handling robot and improved its dynamic characteristics which is meaningful to increase its stability and reliability.

Abstract: An electronic nose based on chemiresistors employing conducting polymers as the sensing material was developed for the discrimination of medicinal plants. The conducting polymers were synthesized through potentiostatic electropolymerization and deposited between two gold wires set 200 μm apart on a Teflon substrate. The polymers were doped with several counter ions. The resistance of the doped polymers changed upon exposure to the headspace of of finely-chopped leaves of the following medicinal plants: Vitex negundo (Lagundi), Mentha arvensis (Yerba Buena), Mentha piperita (Peppermint), Artemisia dracunculus (Taraggon), Blumea balsafimera (Sambong), and Plectranthus amboinicus (Cuban Oregano). The different plant samples yielded distinct responses from the sensor array. The results were subjected to pattern recognition techniques, such as radar plots, principal component analysis (PCA) and dendrogram analysis (DA). PCA showed good discrimination among plant samples. DA confirmed the observed clustering in PCA.

Abstract: In this paper, the security issues in online judge systems (OJ) will be discussed. The pros and cons in different sandbox approaches in open source OJs will be analyzed. After that, well explore other possibilities to build a more suitable sandbox for online judge purpose.

Abstract: The random access technique has a bigger influence to the performance optimization of CDMA data traffic. A CDMA random access technique based on self-similar model and its performance analysis are put forward in this paper. The simulation results indicate that the access performance of CDMA data traffic based on self-similar model is attenuated by power law, related to such parameters as fractal coefficient H and network load G. The CDMA traffic access self-similar equalization protocol (TASEP) is put forward and it can improve the access performance of CDMA data traffic distinctly.

Abstract: Wireless sensor network technology has the potential to reveal fine-grained, dynamic changes in monitored variables of outdoor landscape. But there are significant problems to be overcome in order to realize the vision in working systems, such as effective utilize of energy, prolong network life and improve sensor accuracy. This paper describes the design and evaluation of a sensor network with an effective data aggression algorithm applied in orchard microclimate monitor. A novel feature of the solution is its data compression algorithm design, in which all sensors were encoded with Morton code and a logical multi-lays cluster was constructed among the nodes. Making use of the similarity of the output of the sensors, the algorithm reduces network data amount and power cost significantly to prolong life of the network. Tests and experiments results are shown in diagrammatic form. The system was field tested over one month in Nankou farm located in Beijing province of China. The experimental results demonstrate that effective collecting of environmental information can be achieved by using our proposed system.

Abstract: SIFT (Scale invariant feature transform) and correlative algorithms are now widely used in content based image retrieval technology. They compute distance and use neighbor algorithm to look for the optimal matching couples. The disadvantage of such way is high complexity, especially when huge amount of images need to be retrieved or recognized. To solve this problem, a new matching way based on feature space division under multi-scale is proposed. The algorithm will divide the feature space under multiple scales, so that those feature points which are located in somewhere can use a code to represent, and finally realize the matching through the code. Without calculating distance, the algorithm complexity is greatly reduced. Experiments show that, the algorithm keeps the matching accuracy and greatly enhance the efficiency of the matching at the same time.

Abstract: The background subtraction of an image enables us to distinguish a moving object in a video sequence and enter higher levels of video processing. Background processing is an essential strategy for many video processing applications and its most primary method (utilized to determine the difference of sequential frames) is very rapid and easy, but not appropriate for complicated scenes. In this article we introduce a method to remove the false distinction of the foreground. In our proposed method the updating of which is automatic, a mixture of Gaussians have been used. In addition this method depends on the passage of time. The previously introduced methods are often based on processing on the pixel and ignore the neighbor pixels in order to improve the background. Our method does not make do with one pixel but rather benefits from a block of pixels in order to include all the pixels included in the block. Experimental findings indicate considerable developments in the proposed method which can quickly and without morphological filtering model the background using image supervising cameras placed in both inside and outside locations and lighting changes, repetitive motion from clutter and scene changes. Subsequently the moving object in the scene can appear for real-time tracking and recognition applications.

Abstract: In this work, we examined the non Gauss distribution characteristic and evolution law of the wavelet coefficient of a gust using wavelet transform; according to the time-frequency characteristic, the wavelet transform coefficients and the energy relations of the target velocity spectra are derived; the wavelet coefficient is generated using the cascade model reflecting the turbulent intermittent; the unsteady gust artificial generation method is established based on inverse wavelet transform; and the arbitrary unsteady fluctuation law can be generated by regulating the coefficient of low frequency. The results show that: the natural gust is in good agreement with Karman wind speed spectrum, meets the turbulence-5 / 3 law in the inertial subrange, and exhibits the nature of intermittence and local self-similarity; the artificial wind sequence based on the inverse wavelet transform method shows similar turbulence statistics with natural gust, with which, the effectiveness of the method is confirmed.

Abstract: Social information has multidimensional attributes. With the rapid growth of social information, it's harder and harder to organize, manage, and distribute these large scale information under virtual reality environments in traditional ways. This paper introduces the design and implementation of a social information distributed system based on a distributed virtual reality environment. It allows the users to post and receive social information, share photos, articles and videos with friends. The system is scalable, fault tolerant, and is capable of processing large scale data and supporting tens of thousands of online users.

Abstract: This paper proposed HVAC engineer should simulate natural ventilation () of building based on the Ventilation Network Model (VNM) and software of loop pipe network hydraulic calculation and analysis of hydraulic conditions (LPNHHC) V1.0 which is developed by Chongqing University. It presents two indexes, which are requirement of ventilation in local building regulation () and thermal comfortable ventilation (), should be used to evaluate the design talent on building natural ventilation. We can say the building ventilation design meet the requirement under the premise of bigger than and simultaneously. Architecture, otherwise, needs to modify the building design according to the comments of HVAC engineer. HVAC engineer should design mechanical ventilation (MV) if natural ventilation really can not meet the requirement after modification. It, at last, shows a case study of office building in Chongqing in order to prove the method proposed in the paper. We conclude that ventilation network model can be used to evaluate the design effect of building natural ventilation.