Semantic Segmentation of Large-Scale Outdoor Point Clouds by Encoder–Decoder Shared MLPs with Multiple Losses

Semantic segmentation of large-scale outdoor 3D LiDAR point clouds becomes essential to understand the scene environment in various applications, such as geometry mapping, autonomous driving, and more. With an advantage of being a 3D metric space, 3D LiDAR point clouds, on the other hand, pose a challenge for a deep learning approach, due to their unstructured, unorder, irregular, and large-scale characteristics. Therefore, this paper presents an encoder–decoder shared multi-layer perceptron (MLP) with multiple losses, to address an issue of this semantic segmentation. The challenge rises a trade-off between efficiency and effectiveness in performance. To balance this trade-off, we proposed common mechanisms, which is simple and yet effective, by defining a random point sampling layer, an attention-based pooling layer, and a summation of multiple losses integrated with the encoder–decoder shared MLPs method for the large-scale outdoor point clouds semantic segmentation. We conducted our experiments on the following two large-scale benchmark datasets: Toronto-3D and DALES dataset. Our experimental results achieved an overall accuracy (OA) and a mean intersection over union (mIoU) of both the Toronto-3D dataset, with 83.60% and 71.03%, and the DALES dataset, with 76.43% and 59.52%, respectively. Additionally, our proposed method performed a few numbers of parameters of the model, and faster than PointNet++ by about three times during inferencing.

Cooperative Learning With TSTS Type That Assisted of GMS To Improve Mathematical Communication Skills

Abstrak Penelitian ini bertujuan untuk mendeskripsikan penerapan pembelajaran kooperatif tipe TSTS (Two Stay Two Stray) berbantuan GPS (Geometri mapping study) terhadap kemampuan komunikasi matematis siswa. Penelitia ini dilakukan di kelas VII MTs.Ma’arif Ambulu. Jenis penelitian yang digunakan adalah penelitian tindakan kelas (PTK). Prosedur penelitian yang digunakan mengadopsi teori Kurt Lewin dengan 2 siklus dimana dalam satu siklus terdiri dari empat langkah yaitu perencanaan, tindakan, observasi dan refleksi. Hasil tes siklus I yang telah dilaksanakan diperoleh persentase sebesar 66% dan persentase hasil tes siklus II sebesar 90% dengan nilai minimal berdasarkan KKM yang disesuaikan dengan indikator kemampuan komunikasi matematis secara tertulis. Hal terebut menunjukkan bahwa kemampuan komunikasi matematis siswa mengalami peningkatan dengan diterapkannya model pembelajaran kooperatif tipe two stay two stray berbantuan geometri mapping study.Kata kunci: TSTS, GPS, kemampuan komunikasi matematis Abstrack The purpose of the research is to describe the application of cooperative learning typeTSTS (Two Stay Two Stray) that assisted of GMS (Geometry Mapping Study) to improve students' mathematical communication skills. This research was conducted in class VII of MTs.Ma'arif Ambulu. This type of research is classroom action research (CAR). The research procedure adopted Kurt Lewin's theory with 2 cycles where in one cycle consisted of four steps namely planning, action, observation and reflection. The results of the first cycle test that has been carried out obtained a percentage of 66% and the percentage of the results of the second cycle test by 90% with a minimum value based on KKM adjusted to indicators of mathematical communication skills in writing. It shows that the students' mathematical communication skills have improved with the application of the two stay two stray cooperative learning tipe that assisted by the geometry of study mapping.Keywords: TSTS, GPS, mathematical communiation skills

The application of spherical standards for the evaluation of the accuracy of mapping shape in computed tomography

Anatomical structures are characterized by free surfaces, and most are in lobed and pseudo-spherical shapes. The aim of this article is to analyze selected procedures for accuracy assessment of the shape and dimensions of these structures using certified sphere and Ball Bar standards and to propose metrology parameters facilitating comparison of diagnostic devices. The spherical standard of various materials and Ball Bar standards with various distances between spheres centers can be a tool for evaluation of computed tomography metrology applications. Errors in geometry mapping can be identified on the basis of standardized control systems used in coordinate measuring techniques.

ESL Based Cylindrical Shell Elements with Hierarchical Shape Functions for Laminated Composite Shells

We introduce higher-order cylindrical shell element based on ESL (equivalent single-layer) theory for the analysis of laminated composite shells. The proposed elements are formulated by the dimensional reduction technique from three-dimensional solid to two-dimensional cylindrical surface with plane stress assumption. It allows the first-order shear deformation and considers anisotropic materials due to fiber orientation. The element displacement approximation is established by the integrals of Legendre polynomials with hierarchical concept to ensure theC0-continuity at the interface between adjacent elements as well asC1-continuity at the interface between adjacent layers. For geometry mapping, cylindrical coordinate is adopted to implement the exact mapping of curved shell configuration with a constant curvature with respect to any direction in the plane. The verification and characteristics of the proposed element are investigated through the analyses of three cylindrical shell problems with different shapes, loadings, and boundary conditions.

Design and Optimization of a Cylindrical Voice Coil Actuator for the Synchronized Segmentally Interchanging Pulley Transmission System (SSIPTS)

This paper presents design, modeling, and optimization methodologies for an electromagnetic actuator for the synchronized segmentally interchanging pulley transmission system (SSIPTS). The overall design of SSIPTS and its principle of operation introduce very challenging and conflicting design requirements. The actuators must be very small in size and as light as possible while they need to produce very high force linearly along the stroke. Since no commercial actuator is able to meet all the design requirements of SSIPTS, a novel actuator must be designed for this application. Based on the prior state of the art and literature surveys on actuator technologies and the performance requirements, it has been concluded that voice coil actuator (VCA) technology is the best candidate. VCA is modeled for this application, and the key design parameters have been defined. Further, geometry mapping optimization and FEM analysis have been conducted to determine the optimized values for the key design parameters. Based on the simulation results and FEM analysis, the optimized VCA is shaped. This design of VCA meets the design requirements of SSIPTS.

A NEW CONJUGATED MAPPED INFINITE ELEMENT

Taking the Astley element for example, the conventional mapped infinite element is theoretically dissected in this paper. The study brings to light the reason why the results from the mapped infinite elements vary with the location of the mid-side points used in the geometry mapping. To remedy this deficiency, a new conjugated mapped infinite element is proposed whose shape functions exactly satisfy the multi-pole expansion in the infinite direction. Within the framework of this infinite element, shape functions for any type of wave are composed of the one in the conventional finite element for the same order multiplied by a factor that contains the information of the geometry mapping and the decay behavior of wave. In addition to the slight modification to the phase factor and the weighting factor, the present element permits a free geometry mapping, and therefore greatly expands the applicability of the mapped infinite element methods. To display the performance of the proposed element, typical examples are finally given.