We discuss the use of the block adjustment method for determining astrometric positions from a mosaic of CCD frames taken with a long focus reflector telescope. The observations cover an area of 25 × 25 around the open cluster Rup21. The source of reference positions was the Tycho-2 Catalogue. The internal error in the measured positions is analyzed, and the external error is estimated from com...

In this paper an optimal design of two-stage speed reducer is presented. The novelty of this work consists in the complex and complete approach of the optimal design of gearings. The chosen objective function was the volume bounded by the inner surface of the reducer housing. For this example of optimal design, eleven genes were taken into consideration and a set of thirty six constraints were ...

The rotary vector (RV) reducer is one of the widely used mechanical components in industrial systems, specifically robots. stability transmission performance RV crucial for efficient operation equipment. manufacturing and assembly errors various during production process are important factors that affect performance. However, previous research work, coupling effect multiple on accuracy has not ...

RV reducers are commonly employed in precision transmissions, such as robot joints, owing to their multi-tooth contact characteristics, strong impact resistance, and low backlash. A finite element modal analysis of the reducer was conducted this study reduce influence vibration on transmission performance improve its characteristics. The characteristics analyzed according principles. Combined w...

Clustering big data using data mining algorithms is a modern approach, used in various science and medical fields. k-means clustering algorithm is a good approach for clustering, but choosing initial centers and provides less accuracy guarantees. The enhanced k-means approach called k-means++ chooses one center uniformly at random provides better functionality, but fails to handle data of large...

Optimally hybrid numerical solvers were constructed for massively parallel generalized eigenvalue problem (GEP). The strong scaling benchmark was carried out on the K computer and other supercomputers for electronic structure calculation problems in the matrix sizes of M = 104 − 106 with upto 105 cores. The procedure of GEP is decomposed into the two subprocedures of the reducer to the standard...

Flexible and semi-rigid heat-shrinkable tubes (HSTs) have been used in thousands of applications, and here rigid high temperature HSTs are reported for the first time. These rigid HSTs are prepared with shape memory polyimides possessing glass transition temperatures (Tgs) from 182 to 295 °C, and the relationships between Tg and their molecular structures are studied. The polyimide HSTs (PIHSTs...