Research On The Evaluation Method Of Delivery Error Of Artificial Reefs

At present, in the face of problems, such as the deterioration of the ecological environment, reduction of biological resources, and the level of biodiversity decreased, construction of artificial reefs played a very important positive role in the maintenance and proliferation of fishery resources, coastal habitat restoration and improvement, maintaining and promoting the marine ecosystem health. The construction of artificial reefs includes the selection of reefs site, the design of reefs, the delivery of reefs, the management and maintenance. It is a complex systems engineering. Each of them affects the realization of artificial reefs effect, the launch is an important link of the construction of artificial reefs. The result will have an impact on the layout of reefs, the spacing, and the scale of setting, thereby affecting the effect of the artificial reefs. In the process of the actual delivery of artificial reefs, on account of the restriction of sea conditions and delivery technology and other man-made factors, the distribution of artificial reefs is not completely consistent with the design scheme. There are different degrees of deviations. Therefore, need to the quantitative calculation of the errors and accurate assessment of delivery technology, in order to formulate the effective strategies of control and management, which put the error in a controllable state, in order to ensure the accurate delivery of artificial reefs, promote to maximize effect of the construction, to meet the requirements of the construction of reefs, to achieve the goal of building. How to scientific evaluation on the construction technology of artificial reefs? How to construct a reasonable evaluation standard system? Become the urgent need to study and solve the problems. Therefore, in view of the above problems, this study analyzes the error of artificial reefs are analyzed, mainly has the following several aspects:First of all, this study based on measured data of sonar obtained by field investigation, with the vector function of Arc GIS, get the actual distribution of artificial reefs, on the basis of spatial autocorrelation, with the aid of spatial clustering method in data mining, using three different algorithms(partition algorithm, hierarchical algorithm, constraint algorithm) divided, classified or removed the reefs IV after launching, and select four indicators(the location of the center of gravity, the influence area, reef monomer quantity and reefs spacing) for comparative and analysis, discuss the actual clustering model of artificial reefs. Considering the four factors, results showed that, clustering algorithm based on the constraint of the highest accuracy, can reflect the actual agglomeration situation of artificial reefs.Secondly, according to the result of spatial clustering, comparison is made between the actual situation of artificial reefs and design scheme, considering the layout of reefs, the spacing, the scale of settings and other aspects, select the position of the center of gravity, the peripheral area, the overlapping area, the number of monomer and the spacing of reefs as the error factors for analysis, and compared the fitting situation of each index error distribution, find the probability distribution on the error as accurate as possible, the distribution range of the error are obtained by the distribution rule, quantitative description on the characteristics of the error. The results show that the probability distribution of the same error indicator in different waters is different; probability distribution of a certain error indicator may be subject to a variety of situations in the same waters, but there are fitting precision differences between the different probability distribution model. Normal distribution fitting in the position of the center of gravity error, the overlapping area error, the monomer quantity error, and the reefs spacing error is better, the peripheral area error obeys the exponential distribution, and the overall error distribution is different in different regions. The position of the center of gravity error, the overlap area error and the monomer number error in different regions of the same error limit, error distribution ranges respectively were [0, 1], [0, 1], [0, 0.451], and the limit error of other error factors in different regions was slightly different, in general, the peripheral area error distribution was [0, 1], the distribution ranges of the reefs spacing error and total error were [0, 1], [0, 0.890].Finally, on the basis of the research results on the error distribution, combining the equal width discretization algorithm and the class dependent discretization algorithm, the continuous distribution of artificial reefs is processed with the discrete way, divide the error level of artificial reefs, the error level is divided into 5 levels(good, better, medium, poor, very poor), and the establishment of the evaluation results between hierarchy and percent conversion, making two standard grades on error. Before the comprehensive evaluation, according to the goal of the construction of artificial reefs, weighted by the subjective weighting method for each error indicator, to determine the degree of influence of each error indicator, we obtain the grade on delivery technology of artificial reefs in different waters.