检索结果-南通市图书馆

Computational model for perception of objects and motions

2008北京国际生理科学学术大会

作者： LI Xiang~1,WANG Xu~1,ZHANG Peng~2,CHEN Xiao-Ping~(2,*),FAN Ming~(1,*) 1 Institute of Basic Medical Sciences,Academy of Military Medical Sciences,beijing 100850,china 2 china Astronaut Research and {3. Center,beijing 100094,china

Oxygen conditions influence a variety of biological responses of cells,including alterations in cellular growth,survival and *** concentration of oxygen in atmosphere is 21%,whereas the level of oxygen at the tissue in vivo is significantly *** partial saturation of oxygen found in mature skeletal muscle is reported to be between 1%to 10%.However,there have been few studies on effects of hypoxia on proliferation and differentiation of myoblasts up to *** study has indicated that 3.O promoted proliferation of myoblasts,and in this work,we observed effects of 3.O on myogenic differentiation of C2C12 myoblasts. C2C12 myoblasts were cultured in DM to induce differentiation under either normoxic or hypoxic conditions. Immunocytochemistry analysis for MHC protein showed that C2C12 myoblasts cultured in DM under hypoxic conditions hardly fused into myotubes and expressed MHC protein compared with cells cultured under normoxic conditions,which was also confirmed by Western blot *** blot analysis and RT-PCR showed that the expression of MRFs were down-regulated at protein and transcriptional levels by *** addition,HIF-1αprotein in C2C12 myoblasts was stable and not degraded in normoxia,and HIF-1αexpression in C2C12 myobalsts were hardly influenced by oxygen *** results indicate that 3.O inhibits myogenic differentiation of C2C12 myoblasts,and HIF-1αmay not play an important role in hypoxia-inhibited myogenic differentiation.

关键词： hypoxia C2C12 myoblasts differentiation

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Science china(Life Sciences) 2008年第6期51卷 526-536页

作者： YANG WenLu1,2, ZHANG LiQing1 & MA LiBo1 1 Department of Computer Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, china 2 Department of Electronic Engineering, Shanghai Maritime University, Shanghai 20013., china 1. Department of Computer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China 2. Department of Electronic Engineering Shanghai Maritime University Shanghai 200135 China

Perception of objects and motions in the visual scene is one of the basic problems in the visual system. There exist 'What' and 'Where' pathways in the superior visual cortex, starting from the simple cells in the primary visual cortex. The former is able to perceive objects such as forms, color, and texture, and the latter perceives 'where', for example, velocity and direction of spatial movement of objects. This paper explores brain-like computational architectures of visual information processing. We propose a visual perceptual model and computational mechanism for training the perceptual model. The compu- tational model is a three-layer network. The first layer is the input layer which is used to receive the stimuli from natural environments. The second layer is designed for representing the internal neural information. The connections between the first layer and the second layer, called the receptive fields of neurons, are self-adaptively learned based on principle of sparse neural representation. To this end, we introduce Kullback-Leibler divergence as the measure of independence between neural responses and derive the learning algorithm based on minimizing the cost function. The proposed algorithm is applied to train the basis functions, namely receptive fields, which are localized, oriented, and bandpassed. The resultant receptive fields of neurons in the second layer have the characteristics resembling that of simple cells in the primary visual cortex. Based on these basis functions, we further construct the third layer for perception of what and where in the superior visual cortex. The proposed model is able to perceive objects and their motions with a high accuracy and strong robustness against additive noise. Computer simulation results in the final section show the feasibility of the proposed perceptual model and high efficiency of the learning algorithm.

关键词： visual perception visual cortex computational model receptive fields simple cells complex cells

在线全文

学校读者我要写书评

暂无评论

澳大利亚高水平运动员培养体制调查研究

体育科学 2004年第1期24卷 17-19页

作者：王庆伟许广树李贵成首都体育学院体操教研室北京100088 北京市木樨园体育训练中心北京100075 北京市什刹海体校北京100009

主要采用了实地调查访谈及文献资料调研等方法 ,对澳大利亚优秀运动员的培养体制进行了的研究。研究认为 ,澳大利亚在优秀运动员的培养方面主要采用了政府和社会相结合的模式 ,尤其是各级政府在对培养优秀运动员方面采取了弹性政策 ,充... 详细信息

主要采用了实地调查访谈及文献资料调研等方法 ,对澳大利亚优秀运动员的培养体制进行了的研究。研究认为 ,澳大利亚在优秀运动员的培养方面主要采用了政府和社会相结合的模式 ,尤其是各级政府在对培养优秀运动员方面采取了弹性政策 ,充分利用市场机制培养高水平运动员。这种模式经过第 2 7届悉尼奥运会验证是成功的。在北京取得 2 0 0 8年第 2 9届奥运会举办权之际。

关键词：澳大利亚优秀运动员培养体制弹性政策竞技体育社区体育俱乐部体育组织

Application of a neural network system combined with genetic algorithm to rank coalbed methane reservoirs in the order of exploitation priority

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2008年第4期5卷 334-339页

作者： Li Weichao Wu Xiaodong Shi Junfeng Key Laboratory of Petroleum Engineering Ministry of Education China University of Petroleum Beijing 102249 China

A new method based on the combination of a neural network and a genetic algorithm was proposed to rank the order of exploitation priority of coalbed methane reservoirs. The neural network was used to acquire the weights of reservoir parameters through sample training and genetic algorithm was used to optimize the initial connection weights of nerve cells in case the neural network fell into a local minimum. Additionally, subordinate functions of each parameter were established to normalize the actual values of parameters of coalbed methane reservoirs in the range between zero and unity. Eventually, evaluation values of all coalbed methane reservoirs could be obtained by using the comprehensive evaluation method, which is the basis to rank the coalbed methane reservoirs in the order of exploitation priority. The greater the evaluation value, the higher the exploitation priority. The ranking method was verified in this paper by ten exploited coalbed methane reservoirs in china. The evaluation results are in agreement with the actual exploitation cases. The method can ensure the truthfulness and credibility of the weights of parameters and avoid the subjectivity caused by experts. Furthermore, the probability of falling into local minima is reduced, because genetic the algorithm is used to optimize the neural network system.

关键词： Coalbed methane neural network system genetic algorithm evaluation index weight

Support vector machine applied in QSAR modelling

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2005年第20期 37-42页

作者： MEI Hu1,2, ZHOU Yuan3. LIANG Guizhao3. & LI Zhiliang1,2 1. College of Chemistry and Chemical Engineering, Chongqing Univer- sity, Chongqing 400044, china 2. Key Laboratory of Biomedical Engineering of Ministry of Education and Chongqing City, Chongqing 400044, china 3. College of Bioengineering, Chongqing University, Chongqing 400044, china

Support vector machine (SVM), partial least squares (PLS), and Back-Propagation artificial neural net- work (ANN) were employed to establish QSAR models of 2 dipeptide datasets. In order to validate predictive capabilities on external dataset of the resulting models, both internal and external validations were performed. The division of dataset into both training and test sets was carried out by D-optimal design. The results showed that support vector machine (SVM) behaved well in both calibration and prediction. For the dataset of 48 bitter tasting dipeptides (BTD), the results obtained by support vector regression (SVR) were superior to that by PLS in both calibration and prediction. When compared with BP artificial neural network, SVR showed less calibration power but more predictive capability. For the dataset of angiotensin-converting enzyme (ACE) inhibitors, the results obtained by support vector machine (SVM) re- gression were equivalent to those by PLS and BP artificial neural network. In both datasets, SVR using linear kernel function behaved well as that using radial basis kernel func- tion. The results showed that there is wide prospect for the application of support vector machine (SVM) into QSAR modeling.

关键词： support vector machine (SVM) partial least squares (PLS) back-propagation (BP) artificial neural network (ANN) quantitative structure-activity relationship (QSAR).

Intelligent direct analysis of physical and mechanical parameters of tunnel surrounding rock based on adaptive immunity algorithm and BP neural network

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Pharmaceutical Analysis 2009年第1期21卷 22-30页

作者： Xiao-rui Wang1,2, Yuan-han Wang1, Xiao-feng Jia3..School of Civil Engineering and Mechanics,Huazhong University of Science and Technology, Wuhan 43.074,china 2.Department of Civil Engineering,Nanyang Institute of Technology,Nanyang 473.04,china 3.Department of Chemistry and Bioengineering,Nanyang Institute of Technology,Nanyang 473.04,china. School of Civil Engineering and Mechanics Huazhong University of Science and Technology Wuhan 430074 China Department of Civil Engineering Nanyang Institute of Technology Nanyang 473004 China Department of Chemistry and Bioengineering Nanyang Institute of Technology Nanyang 473004 China

Because of complexity and non-predictability of the tunnel surrounding rock, the problem with the determination of the physical and mechanical parameters of the surrounding rock has become a main obstacle to theoretical research and numerical analysis in tunnel engineering. During design, it is a frequent practice, therefore, to give recommended values by analog based on experience. It is a key point in current research to make use of the displacement back analytic method to comparatively accurately determine the parameters of the surrounding rock whereas artificial intelligence possesses an exceptionally strong capability of identifying, expressing and coping with such complex non-linear relationships. The parameters can be verified by searching the optimal network structure, using back analysis on measured data to search optimal parameters and performing direct computation of the obtained results. In the current paper, the direct analysis is performed with the biological emulation system and the software of Fast Lagrangian Analysis of Continua (FLAC3.. The high non-linearity, network reasoning and coupling ability of the neural network are employed. The output vector required of the training of the neural network is obtained with the numerical analysis software. And the overall space search is conducted by employing the Adaptive Immunity Algorithm. As a result, we are able to avoid the shortcoming that multiple parameters and optimized parameters are easy to fall into a local extremum. At the same time, the computing speed and efficiency are increased as well. Further, in the paper satisfactory conclusions are arrived at through the intelligent direct-back analysis on the monitored and measured data at the Erdaoya tunneling project. The results show that the physical and mechanical parameters obtained by the intelligent direct-back analysis proposed in the current paper have effectively improved the recommended values in the original prospecting data. This is of p

关键词： adaptive immunity algorithm BP neural network physical and mechanical parameters surrounding rock direct-back analysis

Survey Study of Moso Bamboo Management Techniques Dissemination in Zhejiang

在线全文

学校读者我要写书评

暂无评论

Chinese Forestry Science and Technology 2010年第2期9卷 73-81页

作者： WANG Hong1,2XU Xiaowen3.JIN Aiwu3.LI Guodong3.FANG Wei 3.1. School of Forestry, beijing Forestry University,beijing 100083. P.R. china 2. Institute of Forest Resource and Information Techniques, Chinese Academy of Forestry, beijing 100091, P.R. china 3. Bamboo Research Institute of Zhejiang Forestry University, Provincial Key Laboratory of Silviculture in Zhejiang Forestry University, Lin’an 3.13.0, P.R. china

By PRA survey to 1 245 farmer households of 10 key Moso bamboo (Phyllostachys pubescens) production counties, the source and demand of the management techniques in Zhejiang were studied. The conducted principal factor analysis revealed that experience and traditional knowledge are currently major technical sources of farmer households' Moso bamboo forest management techniques and that the demonstrative household is a highly expected technical source, in which the prime factor is interpersonal dissemination with the variable information making up 21.5% of the total. The paper thus suggests that following the nationwide collective forest tenure reform and forest land allocation to the households, the technical sources available to the households should be diversified, that technical training with site expert instruction be taken as priority in establishing demonstrative households for extension and that the current technical extension mode await improvement.

关键词： Moso bamboo participatory rural appraisal second-hand data forest tenure reform

The Organizational Patterns of English and Chinese Texts:A Contrastive Study

在线全文

学校读者我要写书评

暂无评论

现代外语 1999年第4期22卷 408-409页

作者： Liu Lijin, Foreign Languages training CenterGuangdong University Of FOreign StudiesGuangzhou, P R. china 510421

Thispapercontrastivelystudies,basedonthetheoreticframeworkof'topicanalysis'byvanDijkandsomeothers,t***tativesampleofEnglishandCh... 详细信息

Thispapercontrastivelystudies,basedonthetheoreticframeworkof'topicanalysis'byvanDijkandsomeothers,t***tativesampleofEnglishandCh...

关键词： text topic organizational pattern contrastive study

THE 1998 FLOOD OF THE YANGTZE RIVER

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment Research 1999年第4期 61-66页

作者： ZHOU Wenhao1 and CHEN Yuchong2(1 Senior Engineer, china Institute of Water Resources and Hydro-power Research (IWHR), beijing 100044. china.)(2 Engineer, International Research and {3. Center on Erosion and Scdimentation (IRTCES), beijing 100044,Chi

This paper analyses the characteristics of the flood of the Yangtze River in 1998. It is concluded thatsuccessive heavy rainfall in the whole basin, and reductions in storage capacity of lakes and flooddischarge capac... 详细信息

关键词： Flood Max. flood stage Interrelation between river and lakes Sediment deposition Reclaiming lake marshes in the lake area