Diversity of Vegetation in The Natural Forests of Londut Samosir Regency

Londut protected forest contains mixed forest vegetation in the form of natural forest vegetation and there is forest vegetation of former industrial plant forest management, as well as natural tusam vegetation (Pinusmerkusii), also has the privilege of existing conditions that still have natural biodiversity in the form of natural tropical forest vegetation. The research aims to find out the variation and dominance of the type of forest vegetation contained in the area, so that initial information will be obtained in the framework of planning and management of the area. The implementation of research is carried out by the determination of plot methods, and the creation of inventory plots, the creation of inventory plots according to growth rate, inventory path, measurement of vegetation dimensions, and identification. The inventory plot method is carried out with a net system (nested sampling) with an inventory path length of 500 m with a repeat of 5 lanes whose placement is evenly spread over the Londut forest area to get representation. The results showed 31 types of vegetation growing in the region. Based on the diversity of types included in the moderate category as well as the value of the level of the type in the low class. The dominance of vegetation types at the level of seedlings, stake, and poles is occupied by hosting vegetation types (Quercus sp) with magnitudes of 25.90%, 33.94%, and 37.61% respectively. For the level of trees dominated by the type of Tusam (Pinusmerkussii) 57.71%.

Research on Subpixel Algorithm of Fixed-Point Tool Path Measurement

Tool safety is an important part of machining and machine tool safety, and machine tool path image detection can effectively obtain the in-machine condition of a tool. To obtain an accurate image edge and improve image processing accuracy, a novel subpixel edge detection method is proposed in this study. The precontour is segmented by binarization, the second derivative in the neighborhood of the demand point is calculated, and the obtained value is sampled according to the specified rules for curve fitting. The point whose curve ordinate is 0 is the subpixel position. The experiment proves that an improved subpixel edge can be obtained. Results show that the proposed method can extract a satisfactory subpixel contour, which is more accurate and reliable than the edge results obtained by several current pixel-level operators, such as the Canny operator, and can be used in edge detection with high-accuracy requirements, such as the contour detection of online tools.

Improving the accuracy of the synthesis of the amplitude-phase distribution in an antenna array with an arbitrary geometry

Problem statement. One of the constructing antenna arrays (AA) topic is related to the determination of complex amplitudes at the input of the antenna-feeder path, which, taking into account the distortions introduced by the its, ensure the formation of an amplitude-phase distribution (APD), in which the formed DP differed minimally from the set one. The statement of the problem assumes the known number and coordinates of the location of the emitters, the DP of the radiating element in the composition of the radiating opening, a given radiation pattern. It is required to form an APD in a given opening of the AA, which ensures the formation of a DP that has a minimum deviation from the specified one. To solve the problem, the following algorithm is proposed: determination of the APD at the input of the antenna-feeder path, which ensures the formation of a given DP in the absence of distortions introduced by the antenna-feeder path; measurement for the selected directions of the generated DP with the selected APD in the presence of APD distortions introduced by the antenna-feeder path; formation of a refined APD that ensures the fulfillment of required condition in the presence of distortions introduced by the antenna-feeder path of the AA. Objective. Minimize the root-mean-square deviation of the generated PD from the one specified for the AP with the opening of an arbitrary geometry. Results. The results obtained showed: The formulation of the problem of synthesis of the APD allows us to consider, within the framework of a single approach, AA with different geometries, including AA with a non-planar radiating opening, no restrictions are imposed on the shape of the boundary, and linear (quasi-ring) AA, the emitters of which are located along an arbitrary mane. Using the proposed algorithm for the synthesis of APD, which includes three main stages: the formation of APD for a given DP; measurement of complex values of the generated DP; refinement of the APD by determining the corrections while minimizing the standard deviation (SD) between the specified and formed at the first stage of the DP, allows us to form an APD that provides a minimum SD between the specified and formed DP. The performed studies have shown that when choosing the number of angular directions in each plane, comparable to the number of emitters in this plane, there is a large difference between the given and formed DP. When the number of angular directions for measuring the DP is approximately three times greater than the number of emitters in a given plane, the SD between the specified and formed DP is close to the minimum value and practically does not change with further increase.

State-of-the-art ultrasonic sensor designed to improve longwall production rates and operation safety

The article describes issues related to the development of a sensor measuring the distance from the end of the shield support canopy to the face of the longwall panel. The sensor's task is to detect rock falls because in such a case, empty spaces in the coal seam below the roof are generated. The sensor is a part of the system which task is to predict unfavourable behaviour of the longwall roof affecting the continuity of mining. Due to an untypical workplace and difficult conditions prevailing there, it was not possible to use a typical sensor. The ultrasonic technique was used for this purpose. The next research stages related to the development of the sensor were described. Tests of various types of ultrasonic transducers, working at different parameters, were described. Only transducers with a closed structure were considered because they can operate in the presence of high dustiness and humidity. The sensor casing was adapted to a specific type of shield support. The installation location should not be accidental, as an additional hinged shield is mounted at the end of the canopy, which is an obstacle in the measuring track and can even completely cover it, making measurements impossible. The sensor is mounted close to the side edge of the shield support canopy using small free space, enabling a measurement. Structural elements of the canopy are obstacles in the measuring track and are a source of interference of the received signals. The ultrasonic transducers are built-in tubes, which direct the ultrasonic wave and amplify the received signals. The results of laboratory tests of the model of the path measurement sensor are presented. They describe the impact of analysed aspects, i.e. the type of transducers used, the structure of the surface that the wave is reflected from and the mechanical solutions on the quality of received signals. A prototype of a sensor installed on shield support is presented.