A Variation Reduction in the Tele-Abrasive System: A Study of Human Movement

In a tele-abrasive task, it is principally human arm movements that cause variation in the position of the abrasive nozzle, thereby resulting in high operating costs and low productivity. It is difficult to design a system that can minimize the variation that accrues from operators behaving differently, which is difficult to predict. Although skilled operators can reduce this variation, becoming a skillful operator requires a lengthy training period. In this work, a two-stage variation streaming technique was used to extract variation sources in a tele-abrasive system. Furthermore, we propose an integrated human–computer approach to control variation in these systems—an approach that applies an innovative human arm movement pattern incorporated with a Kalman filter into a standard system. A virtual tele-abrasive system was used to validate our approach. Furthermore, compared with conventional systems, the proposed approach will help operators to perform abrasive tasks more comfortably and require a shorter training period.

Variation propagation modeling in multistage machining processes considering form errors and N-2-1 fixture layouts

Variation propagation modeling of multistage machining processes enables variation reduction by making an accurate prediction on the quality of a part. Part quality prediction through variation propagation models, such as stream of variation and Jacobian-Torsor models, often focus on a 3-2-1 fixture layout and do not consider form errors. This paper derives a mathematical model based on dual quaternion for part quality prediction given parts with form errors and fixtures with N-2-1 (N>3) layout. The method uses techniques of Skin Model Shapes and dual quaternions for a virtual assembling of a part on a fixture, as well as conducting machining and measurement. To validate the method, a part with form errors produced in a two-stationed machining process with a 12-2-1 fixture layout was considered. The prediction made following the proposed method was within 0.4% of the prediction made using a CAD/CAM simulation when form errors were not considered. These results validate the method when form errors are neglected and partially validated when considered.

Method of estimation of frequency variation relying on estimation of shift of spectral peaks

Problem of estimation of variated frequency of components of polyharmonic signals has been arose. Three-dimensional time-frequency representation of signals is usually used to resolve this problem. But simple and reliable method of instantaneous frequency tracking is needed. Frequency tracking method based on estimation of shifts of peaks of spectrogram has been proposed in this paper. It is assumed that shift of spectral peaks of components of signal is proportional to variation of fundamental frequency. Logarithmic scaling of time-frequency representation is used to make spectral peaks equidistant. Temporal dependence of shift of spectral maximums is obtained using correlation of windowed spectrum at the first frame and spectrum of signal in the current window. Then obtained track is translated in linear scale. Proposed method does not estimate values of instantaneous frequency or central frequency of signal component but estimates its variation. Advantage of the method is that it can estimate frequency track even if range of frequency variation and its central value are known roughly or unknown at all. Multiple components do not interfere to estimate fundamental frequency variation. Reduction of bandwidth is recommended to increase accuracy of frequency track estimation, but analysis of time-frequency representation containing a few components is also possible. Dependency of performance of analysis of synthetic signals using the method on various signal to noise ratios under different conditions was estimated. Applicability of the method for vibrational diagnosing of rotary equipment was checked out using spectral interference method.

Pedigree Analysis of Warmblood Horses Participating in Competitions for Young Horses

The aim of the study was to characterize the population structure and assess the genetic diversity of warmblood horses used in the show jumping discipline. Pedigree data of 1,048 horses participating in the Polish Championships for Young Horses were analyzed. The pedigree of these animals included 12 863 individuals. The study consisted in analysis of the pedigree structure of the horses and characterization of the homozygosity and genetic diversity in the population. It was found that pedigree completeness and depth were sufficient for reliable assessment of the genetic diversity in the analyzed population. Although the average inbreeding coefficient exhibited at an acceptable level (approx. 1.01%), the increasing percentage of inbred animals seems disturbing. The results have shown that modern sport horses are derived from a small number of high-quality sires whose offspring were intensively used for breeding—bottleneck effect. In consequence, a greater part of the genetic variation reduction was observed in the non-founder generations. Given the changes in the studied population, the level of inbreeding in modern sport horses should be monitored, and pedigree data should be effectively used in selection for mating.

Low Inertia Systems Frequency Variation Reduction with Fine-Tuned Smart Energy Controllers

The distributed and stochastic nature of Renewable Power Sources is certainly forming considerable challenges for the operation of the power system. Specifically, the stability of the system can be jeopardized when the penetration of inverter-based systems is high. Storage and the proper design of controllers is seen as part of the solution for supporting the future expansion of distributed systems. Thus, control strategies need to be designed to provide the appropriate support to the system and be capable of keeping the variation of the frequency within limits to keep the reliability of the system as high as possible. The main challenge is the appropriate parameterization of these distributed controllers and their coordination under the integrated grid approach in securing the stability of the system at all times. In this paper, a smart energy controller is utilized and incorporated into the projection case study for Cyprus’ real distribution grid for the year 2050 to evaluate its behavior and identify possible weaknesses in its usage. It was found that the parameterization and not only the architecture of such controllers is crucial in coping with the frequency variation and stability problem. From the simulation work and recorded results, it was observed that the smart energy controllers can maintain frequency variation within the desirable range when the parametrization of the controllers is chosen appropriately. This specific observation highlights the need to evaluate and configure the smart controllers while operating in the field, and possibly further research is required to provide the advanced capability to such systems to adjust dynamically during field operation, thereby achieving better response during abnormal conditions.

Practicing Integrated Care Pathways in Norwegian Hospitals: Coordination through Industrialized Standardization, Value Chains, and Quality Management or an Organizational Equivalent to Improvised Jazz Standards

The goal of coordinating pathways for cancer patients through their diagnostic and treatment journey is often approached by borrowing strategies from traditional industries, including standardization, process redesign, and variation reduction. However, the usefulness of these strategies is sometimes limited in the face of the complexity and uncertainty that characterize these processes over time and the situation at both patient and institutional levels. We found this to be the case when we did an in-depth qualitative study of coordination processes in patient pathways for three diagnoses in four Norwegian hospitals. What allows these hospitals to accomplish coordination is supplementing standardization with improvisation. This improvisation is embedded in four types of emerging semi-formal structures: collegial communities, networks, boundary spanners, and physical proximity. The hierarchical higher administrative levels appear to have a limited ability to manage and support coordination of these emerging structures when needed. We claim that this can be explained by viewing line management as representative of an economic–administrative institutional logic while these emerging structures represent a medical–professional logic that privileges proximity to the variation and complexity in the situations. The challenge is then to find a way for emergent and formal structures to coexist.