Process Monitoring in Ultrasonic Metal Welding of Lithium Batteries by Power Signals

Ultrasonic metal welding is one of the key technologies in manufacturing lithium batteries, and the welding quality directly determines the battery performance. Therefore, an online welding process monitoring system is critical in identifying abnormal welding processes, detecting defects, and improving battery quality. Traditionally, the peak welding power is used to indicate abnormal process signals in welding process monitoring systems. However, since various factors have complex impacts on the electric power signals of ultrasonic welding processes, the peak power is inadequate to detect different types of welding defects. Therefore, a signal pattern matching method is proposed in this study, which is based on the electric power signal during the entire welding process and thus is capable of identifying abnormal welding processes in various conditions. The proposed method adopts isometric transformation and homogenization as signal pretreatment methods, and Euclidean distance is used to calculate the similarity metric for signal matching. The effectiveness and robustness of the proposed method are experimentally validated under different abnormal welding conditions.

GIANA allows computationally-efficient TCR clustering and multi-disease repertoire classification by isometric transformation

Similarity in T-cell receptor (TCR) sequences implies shared antigen specificity between receptors, and could be used to discover novel therapeutic targets. However, existing methods that cluster T-cell receptor sequences by similarity are computationally inefficient, making them impractical to use on the ever-expanding datasets of the immune repertoire. Here, we developed GIANA (Geometric Isometry-based TCR AligNment Algorithm) a computationally efficient tool for this task that provides the same level of clustering specificity as TCRdist at 600 times its speed, and without sacrificing accuracy. GIANA also allows the rapid query of large reference cohorts within minutes. Using GIANA to cluster large-scale TCR datasets provides candidate disease-specific receptors, and provides a new solution to repertoire classification. Querying unseen TCR-seq samples against an existing reference differentiates samples from patients across various cohorts associated with cancer, infectious and autoimmune disease. Our results demonstrate how GIANA could be used as the basis for a TCR-based non-invasive multi-disease diagnostic platform.

Application of isometric transformation and robust estimation to compare the measurement results of steel pipe spools

Production of prefabricated pipe spools for the needs of the oil and gas industry requires precise determination of their shape and dimensions. The crucial moment of production is to measure the spool being built, compare it with the design and define the geometry corrections that should be applied at the construction stage. At present, the comparison of spools is usually done in a manual manner in a CAD program or other software dedicated for this purpose and is implemented by combining variously defined translations and rotations. This approach is time-consuming and the results strongly depend on the survey engineer’s experience. In this article, a method of comparing the shape of two spools, based on isometric transformation and robust estimation, has been proposed. This method can be used to automate the comparison process. In standard approach, applied by both design engineers and assemblers, spools are described by a set of coordinates and, in the case of flanges, by sets of appropriately defined angular values. A method of flange description suitable for use in the isometric transformation process has been proposed, and potential problems that may appear at the implementation stage of the algorithm have been discussed. The proposed method makes it possible to determine the elements of a spool that do not fit into the design project in a way that allows minimizing the number of corrections at the construction stage.

Central rotation of regular (and irregular) musical poligons

The text describes the application of one of the most important isometric transformations to the projected metro-rhythmic entities of individual harmonics of the spectrum. It is a direct isometry called central rotation. Central rotation conditions the hemiola structuring of the meter. Hemiolas are identified with regular and irregular geometric figures (primarily triangles) by means of a partition and the composition (index) number of a particular spectral harmonics. The partition and composition of numbers, which are dealt with in discrete mathematics, on the one hand, and, the technique of horizontal hemiolas, characteristic of the polyphony of the sub-Saharan region, on the other, served as a means of creating methods by which the isometric transformation of central rotation would be realized in (musical) time.

Triggering fourth graders’ informal knowledge of isometric transformation geometry through the exploration of Malay cloth motif

Existing study revealed that the children have dynamics spatial sense on objects. One of important mathematics topics that can be related to the sense-triggering process is the isometric transformation geometry including reflection, translation, and rotation. This topic is introduced to the fourth and the fifth graders of elementary school. However, learning process in school tends to lack concern on this students’ readily-triggered ability. There is also insufficient number of hands-on activities experienced by the students. It is poor since the hands-on activities can facilitate students’ informal knowledge of isometric transformation geometry. Therefore, this two cycled design research aims to counter such situation. It was conducted at State Elementary School 001 of Toapaya, Kabupaten Bintan, Kepulauan Riau by using RME approach. The subject of the study was the fourth graders. Malay cloth motif was used as the context of the study through the exploration activities. The results indicated that the activities could trigger students’ informal knowledge of: reflection, translation, rotation, constant factors, and transformation composition.

New approach to isometric transformations in oblique local coordinate systems of reference

The research article describes a method of isometric transformation and determining an exterior orientation of a measurement instrument. The method is based on a designation of a “virtual” translation of two relative oblique orthogonal systems to a common, known in the both systems, point. The relative angle orientation of the systems does not change as each of the systems is moved along its axis. The next step is the designation of the three rotation angles (e.g. Tait-Bryan or Euler angles), transformation of the system convoluted at the calculated angles and moving the system to the initial position where the primary coordinate system was. This way eliminates movements of the systems from the calculations and makes it possible to calculate angles of mutual rotation angles of two orthogonal systems primarily involved in the movement. The research article covers laboratory calculations for simulated data. The accuracy of the results is 10-6 m (10-3 regarding the accuracy of the input data). This confi rmed the correctness of the assumed calculation method. In the following step the method was verifi ed under fi eld conditions, where the accuracy of the method raised to 0.003 m. The proposed method enabled to make the measurements with the oblique and uncentered instrument, e.g. total station instrument set over an unknown point. This is the reason why the method was named by the authors as Total Free Station - TFS. The method may be also used for isometric transformations for photogrammetric purposes.

Vector Products As A Tool For The Investigation Of The Isometric Transformation Of Objects

The identification of isometric displacements of studied objects with utilization of the vector product is the aim of the analysis conducted in this paper. Isometric transformations involve translation and rotation. The behaviour of distances between check points on the object in the first and second measurements is a necessary condition for the determination of such displacements. For every three check points about the measured coordinate, one can determine the vector orthogonal to the two neighbouring sides of the triangle that are treated as vectors, using the definition of the vector product in three-dimensional space. If vectors for these points in the first and second measurements are parallel to the studied object has not changed its position or experienced translation. If the termini of vectors formed from vector products treated as the vectors are orthogonal to certain axis, then the object has experienced rotation. The determination of planes symmetric to these vectors allows the axis of rotation of the object and the angle of rotation to be found. The changes of the value of the angle between the normal vectors obtained from the first and second measurements, by exclusion of the isometric transformation, are connected to the size of the changes of the coordinates of check points, that is, deformation of the object. This paper focuses mainly on the description of the procedure for determining the translation and rotation. The main attention was paid to the rotation, due to the new and unusual way in which it is determined. Mean errors of the determined parameters are often treated briefly, and this subject requires separate consideration.

An Approach of Similarity Analysis for Non-Rigid Models Based on Diffusion Map with Thin-Plate Spline

Isometric transformation with geodesic distance is widely used in similarity analysis or 3D retrieval of non-rigid objects. However, geodesic distance is sensitive to topology noise and can be problematic in cases where objects topology is changed locally. In order to solve the problem, a new method based on diffusion map was proposed. We used diffusion map to compute embedded models and utilized thin-plate spline (TPS) to match the embedded models to obtain the similarity error of original objects. The method was tested on some examples, the results show that the new method is suitable to similarity analysis or 3D retrieval of non-rigid objects, moreover, our method is robust to the deformed objects with topology noise.

Acoustic Signal Recognition Based on Time Series Model

Using time series model, isometric transformation time series model and ARTAFIT model, we deal with acoustic signal, obtaining different sets of parameters according to different acoustic signals. We use support vector machine (SVM) to recognize different acoustic signals by analyzing different sets of parameters. When the parameter set is too large, we should first reduce order making use of principal component analysis (PCA), then we can recognize them using support vector machine. In the end, we give a case study, which indicate the results of applying our models are satisfactory.