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In order to practice the concept of coordinated development of “Lucid Waters and Lush Mountains are Invaluable Assets” and “mountains, rivers, forests, farmlands, lakes, grasslands and deserts are part of the community of life”, this study takes “pursuing green development and promoting harmony between humanity and nature” proposed in the report of the 20th National Congress of the Communist Party of China as the theoretical guidance. With the goal of enhancing ecosystem integrity and connectivity, enhancing population communication, enhancing population viability, and providing a model for the construction of ecological corridors for flagship species, based on the current distribution and habitat selection strategies of Asian elephants, the study follows the technological process of “Obtaining species distribution—Identifying habitat sources and resistance surface relating to elephant distribution—Constructing corridors based on the least cost path model—Extracting corridor centrality, pinch points, and barrier through circuit theory—Field investigation and validation—Adjusting and optimizing corridor design—Recommending corridor construction design scheme—Carrying out long-term monitoring of wildlife utilization of corridors”, and suggests construction idea of Asian elephant ecological corridor and related conservation advices. Above conceptions and advice serve for the strategic layout of “intensifying the protection of ecosystems”, “improving the system of shields for ecological security, and developing corridors and biodiversity protection networks”, providing technical support for scientific protection and effective management of Asian elephant population, offering a scientific basis for habitat restoration and layout of planned national parks and other protected area. [ABSTRACT FROM AUTHOR]

The historic urban landscape (HUL) concept is a protection concept proposed for the “continuous” change characteristics and “layered” presentation of cultural landscapes in cities in time series. In this article Taiyuan city was taken as an example, by crawling and sorting the historical relics in Taiyuan, and using the combination of AHP-GIS, to visually identify the historical and cultural landscape space of Taiyuan and quantitatively evaluate the value of historical and cultural landscapes. It was concluded that the historical landscape characteristics of Taiyuan urban area are divided into historical and cultural corridor spaces with “dual core” patches. In the context of the “Belt and Road” intiative, the evaluation results can provide an intuitive scientific basis for further cultural response and planning development of Taiyuan. In addition, the research results prove that the AHP-GIS method is practical and effective for the evaluation of urban historical landscape under the concept of HUL.

As the entrance structure of dry dock chamber, the caisson of floating dock gate is constructed by cast-in-situ technology, which is very difficult to be constructed. This paper introduces in detail the cast-in-situ construction method of caisson of floating dock gate, the form of reserved jacking corridor, the installation method of embedded parts of Ω-type water stop, the jacking method of caisson, the falling mode of caisson, and the application effect of water stop construction. The construction technology of cast-in-situ floating dock gate has been successfully applied to the dry dock prefabrication yard of Dalian Bay subsea tunnel project. The construction experience and related construction parameters have been accumulated, which can provide reference for similar cast-in-situ caisson structure engineering. [ABSTRACT FROM AUTHOR]

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In order to facilitate later maintenance, the underground conveying corridor is moved up to the inside of the squat silo. This process reform is bound to have an impact on the pressure distribution of the wall and corridor. In this study, the loading and discharge experiments of the reduced-scale silo models with different aspect ratios and eccentricity ratios were carried out. Three kinds of PMMA cylinders with different heights were used to simulate the wall. The outer diameter of the cylinder is 1 000 mm, the wall thickness is 10 mm, and the height is 392 mm, 642 mm, and 892 mm, respectively. Three different lengths of ground conveying corridors are made of 10 mm thick steel plate, which are one main corridor and two secondary corridors. The strip eccentricity of the main corridor is zero, and that of the two secondary corridors is 300 mm. In order to consider the influence of eccentricity ratios, five discharge openings are set on the top wall of the main corridor to simulate central and eccentric discharge. In order to explore the influence of aspect ratios, three silos with different aspect ratios (0.44, 0.69, 0.95) are used. The cylinder and the corridors are placed on the steel support. A total of three main and secondary corridors were placed in the silo model, and the manual loading mode was adopted. All the openings on the top wall of the corridors were blocked first, and then the stored material was loaded from the top of the model. When the stored material in the full state of the model was completely stable, the pressure data were recorded by the test system. The results of the loading tests showed that the lateral pressure at the bottom of the silo wall was affected by the corridors. The lateral pressure of the wall in the corridor height range is significantly smaller than the predicted value of the silo standard. The whole discharge process can be summed up as a process of continuous undercutting of the inverted cone, and the vertex of the inverted cone is always located directly above the discharge opening. The phenomenon that the overpressure coefficient increases with the eccentricity of discharge was not observed. The overpressure coefficients of the wall and corridor were generally small when the aspect ratio was below 0.69, and the overpressure coefficients of the wall and corridor increases rapidly when the aspect ratio was close to 1.0. If the conveying corridor was determined as a deep buried corridor according to the standard GB 50077-2017, the predicted value of corridor pressure was obviously less than the test value. It was more reasonable to calculate the static pressure on the top and side wall of the main and secondary corridors according to the shallow buried formula proposed in this study, in which the storage height should be taken as the actual storage height of the corridor. It is suggested that the coefficient of overpressure on the top and side wall of the corridor should be considered properly in the design of squat silos, which can be 1.2-1.3. [ABSTRACT FROM AUTHOR]

This paper proposes a new corridor edge detection and navigation algorithm based on laser scanner data for greenhouse mobile robots. The type of laser scanner is SICK LMS-30206, and the data in each group include 361 distance values in a single scan. All the values will queue in an angle-ascending order, with 0 degree as the start and 180 degree as the stop. For the corridor edge detection task, the algorithm will intensify the fluctuating features of the range values in the same scan by background removing. Then the modified scan will be divided into 24 equal subsectors. The mean square error of range value of each subsector will be computed and compared. The subsector with the minimum mean square error of range value will be taken as the corridor candidate. And bi-direction expending search will be launched for the corridor candidate. The expending search will stop at the point whose adjacent range value difference is larger than a predefined threshold. When the search stops, the corresponding laser beam serial numbers of the corridor edges will be found. As other objects may be mistaken as corridor when they are located in the neighborhood area of corridor and share similar range values with corridor scan points, a pseudo-corridor removing strategy is also presented. With the help of a benchmark corridor width, the pseudo-corridor scan points can be removed. The corridor edges can be used to generate speed control orders for the mobile robot. A new developed front-wheel-driven mobile robot called Walle is employed as the experimental platform. Walle has 4 wheels. The 2 front wheels are equipped with servo motors. The 2 rear wheels are universal. It can change its heading direction in a differential walking mode. In the navigation process, the center of the scan line in the corridor is chosen as the navigation goal for each speed control sampling period, and the speed differential between the 2 driving wheels is the main control parameter. By analyzing the geometrical and kinematical relationships, a transfer function between the expected steering error and the speed differential can be built. Then the speed differential can be induced from the corridor edge information based on the transfer function. Finally, speed-altering control orders can be generated according to the speed differential. Here the new algorithm chooses to speed up one wheel and slow down the other for obtaining the expected speed differential. Experiments are conducted on Walle under different environmental conditions, including the indoor corridor, the outdoor curve routine, and the inner-greenhouse corridor. The robot can navigate itself in the indoor corridor scene with a mean horizontal error of 1.2707 cm and a mean square error of 2.6772 when following the corridor center line. Also, Walle can navigate itself in the outdoor curve routine and the inner-greenhouse corridor successfully. Because Walle lacks the self-localization sensors on board, the real-time position values can't be obtained and recorded for the outdoor curve routine and the inner-greenhouse corridor cases. Two website addresses of the experimental videos are given as remedial measure. The feasibility of the new algorithm is verified through the experiments mentioned above. [ABSTRACT FROM AUTHOR]