【文章內(nèi)容簡介】 ost convenient is to use the steepest descent method to get the minimal value of , when , we get the ideal value of the variables and .. 4 NN’s use to classify leaves Through , single several models leaves and grouping and number of them. Then , learning each group, is acquaintance each models. If want to classify one leaf. We are able to let to solve this problem, eventually, we classify the leaf as likemodel. Studying the reasons of the various shapes that leaves have.Leaves have a variety of forms. There are lots of reasons account for leaves varying in shapes and size, listed as follows: Overall, the reasons can be divided into external and internal factors.External factors:l Seasons and climate (including wind, sunlight, moisture, temperature)。l Plant diseases and insect pests。l Artificial factor。Internal factors:l Deformation of cells, moisture loss of Mesophyll cells may cause volume decrease。l Phytohormone auxin。l Difference gene.we believe that there exits 4 base factors that lead to the variety of leaves shape. They are climate, disease, phytohormone and gene. And we endeavor find out reasons to them.climate: the change of sun shine，water，temperature，humidity which alters leaves shape.disease: through effecting the activity of an enzyme, so that influence leaves shape.Phytohormone auxin: have influence on gene expressiongene: through DNA determine the general leaf shape Set up a AHP model to value these base factorsWe solve this problem based on the reasons listed above. After analyzing all of them, we hold an opinion that human attempt is usually fairly haphazard. Since we view all the leaves’ living environment is stable, we don’t take artificial factor into consideration. We definite total impact as target layer”, and climate, disease, phytohormone, gene as the criterion layer. As shown in the following figure :Total impactClimateDiseaseAuxinGeneFigure ：reasons for the various shapes Paired parison matrix structureTo analyze the effects of electric vehicles’ widespread use on the environment, social, economic and health, we each take two factors: They are used to represent environmental, economic, social and health by turns. All results are available the following pairwise parison matrix: Obviously: The result we used paired parison of the paired parison matrix is:When we take parison of them qualitatively, there are five clear hierarchy in people39。s minds usually, which is expressed as:Table : the meaning of the Measure 19Meaning1 and have the same influence3has a slightly stronger influence than 5has stronger influence than 7has significantly stronger influence than 9has Absolutely stronger influence than 2,4,6,8he ratio of the influence of tolocates between the two near classes1,1/2，1/9he ratio ofisthereciprocalof Calculation of the weight vector and the consistency testUse MATLAB software to calculate the pairwise parison matrix for the largest eigenvalue and the maximum eigenvector that the eigenvalue corresponding. Then we will normalization the abovementioned vector, the normalized results as the weight vector of the parison factor. Following the results: Usually, the pairs parison matrix is not the same array. But if its feature vectors of eigenvalue corresponding can be used as a weight vector of factors to be pared, the extent of its inconsistency should be within the range of: Selecting in this type has a certain subjective wishes. represents consistency index, represents its Random Consistency Index, represents its consistency ratio.Table :1234567891000From the equation above we can draw:From the table above, we can get:The corresponding is This means our model has passed the consistency test, can be used as a weight vector.From the analysis we elicit a conclusion that gene is maximally impacted, and then gene, phytohormone, climate, dease is following. Optimize leaves shape for maximize exposure Explain and answer requirmentFrom the model 2’s conclusion we get above, we acquaint that sunlight is a critical factor for plants. Plants are photoautotrophs, obtain their own energy through photosynthesis and produce oxygen in the meantime. From evolutionary considerations, it seems that the leaves always in a favorable direction, so that they can maximize their exposure to the sun. As is considered above, sunlight changes the blade shape through influencing the distribution of growth hormones. Thus we discuss this issue from the perspective of growth hormones. First of all, we need to know more specifically how growth hormones affect leaves. Growth hormones is a directional transport, but sometimes it transports to the backlight. By inhibiting the growth of the shaded side to effects the phototropism movement of plants. Due to this phenomenon leaves “do their best efforts” make themselves exposed. In other words , It is to minimize mutual shading impact. We try to build cells mechanic model to solve this problem, meanwhile, explain reasons for this phenomenon.Conclusion: plants always “optimize” their leaves shape for maximize exposure. Put another way, they are “minimize” overlapping individual shadows that are cast. The result can primely explain the reasons. Set up a Elastic mechanics modelWe choose Elastic mechanics model to simplify and imitate Physical force of mesophyll cells. We assume that each cell of leaf is subject to two forces, one is the expansive force generated by cytoplasm of cells inside。 another one is external tension generated by cell wall, as shown in figure .Figure ：Elastic rigid modelIn order to describe the two physical forces leaf cells suffered more accurately. We can build contractive spring to present the expansive force of the cell, similarly, tension springs