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The purpose of this paper is to present an approach of modelling and analysis of the dynamic behaviour of manufacturing systems. The manufacturing system is considered to be responding to an excitation, namely a demand that varies over time, by producing a number of parts over time. This resembles a mechanical system that displaces its mass responding to a varying input force. Based on this analogy, this paper establishes a manufacturing system's modelling method. A system identification technique is used for deriving inertia, damping and stiffness from the manufacturing system's response to different excitations. Based on these attributes, the response of a manufacturing system to any given input can be estimated. Furthermore, a definition for assessing manufacturing flexibility, based on this approach, is being discussed. [ABSTRACT FROM AUTHOR] more...

The objective of this work is to describe a method of assessing the flexibility of a manufacturing system, in an uncertain market environment, under lifecycle considerations. The flexibility of a manufacturing system is determined by statistical analysis of the discounted cash flow (DCF) estimates of the manufacturing system's lifecycle cost, over a time horizon and for a large variety of market scenarios. The system's lifecycle cost is calculated at a minimum level with the help of a specially developed algorithm. The method is used in a test case for investing in a production system, using real-life data derived from the automotive industry. [ABSTRACT FROM AUTHOR] more...

In many industrial cases, the nesting problem and the scheduling problem have to be addressed at the same time. The complexity of the combined problem often prevents to take effectively into account both nesting efficiency and overall production objectives. This paper presents a scheduling approach for the combined problem of production scheduling and nesting. The aim of the proposed approach is to provide a good solution both for the nesting and scheduling problem. The approach involves the generation of scheduling alternatives, their transformation through a rule base mechanism into nesting solutions and finally their evaluation using different criteria that reflect the overall production objectives such as meeting due dates, minimizing of the cost and maximizing the machines and stock sheet utilisation. The proposed approach has been implemented in a software system for the purpose of solving a problem in the textile industry. Specifically, the scheduling of the carpet weaving processa problem of nesting rectangular patterns under complex production constraints-has been examined. A set of experiments has been conducted for producing realistic nesting schedules in order to evaluate the proposed system's performance. The results show that the proposed approach may be applied in real-life manufacturing processes under complex production constraints and multiple objectives. [ABSTRACT FROM AUTHOR] more...

Tracking human operators working in the vicinity of collaborative robots can improve the design of safety architecture, ergonomics, and the execution of assembly tasks in a human-robot collaboration scenario. Three commercial spatial computation kits were used along with their Software Development Kits that provide various real-time functionalities to track human poses. The paper explored the possibility of combining the capabilities of different hardware systems and software frameworks that may lead to better performance and accuracy in detecting the human pose in collaborative robotic applications. This study assessed their performance in two different human poses at six depth levels, comparing the raw data and noise-reducing filtered data. In addition, a laser measurement device was employed as a ground truth indicator, together with the average Root Mean Square Error as an error metric. The obtained results were analysed and compared in terms of positional accuracy and repeatability, indicating the dependence of the sensors' performance on the tracking distance. A Kalman-based filter was applied to fuse the human skeleton data and then to reconstruct the operator's poses considering their performance in different distance zones. The results indicated that at a distance less than 3 m, Microsoft Azure Kinect demonstrated better tracking performance, followed by Intel RealSense D455 and Stereolabs ZED2, while at ranges higher than 3 m, ZED2 had superior tracking performance. more...

The case of a 37-year-old man with chronic hepatitis C virus (HCV) infection is presented. The patient had received a 6-month course of antiviral therapy with peg interferon alpha-2a and ribavirin, with concomitant clearance of hepatitis C virus ribonucleic acid (HCV-RNA) from serum at the end of treatment. Three months after the treatment course he developed clinical and laboratory features of hypothyroidism along with high titers of thyroid peroxidase antibodies. Later on, while on treatment with levothyroxine, he developed all the clinical features of Graves disease along with increased levels of thyroid stimulating hormone (TSH)-receptor antibodies.This patient exhibited a rare sequence of immune-mediated thyroid disorders as a result of interferon alpha treatment. At the end of treatment, the patient developed Hashimoto thyroiditis, a typically Th1-response-mediated disease, followed sequentially after 6 months by Graves disease, a typically Th2-response-mediated disorder. Although both clinical entities have been described in patients receiving interferon-based regimens, to our knowledge, the changing pattern of immune-mediated thyroid disease in the same individual has not been reported in the literature. more...