A Distributed Supervisor Architecture for a General Wafer Production System

The current trend in the wafer production industry is to expand the production chain with more production stations, more buffers, and robots. The goal of the present paper is to develop a distributed control architecture to face this challenge by controlling wafer industrial units in a general production chain, with a parametric number of production stations, one robot per two stations where each robot serves its two adjacent production stations, and one additional robot serving a parametric number of stations. The control architecture is analyzed for individual control units, one per robot, monitoring appropriate event signals from the control units of the adjacent robots. Each control unit is further analyzed to individual supervisors. In the present paper, a modular parametric discrete event model with respect to the number of production stations, the number of buffers, and the number of robotic manipulators is developed. A set of specifications for the total system is proposed in the form of rules. The specifications are translated and decomposed to a set of local regular languages for each robotic manipulator. The distributed supervisory control architecture is developed based on the local regular languages, where a set of local supervisors are designed for each robotic manipulator. The desired performance of the total manufacturing system, the realizability, and the nonblocking property of the proposed architecture is guaranteed. Finally, implementation issues are tackled, and the complexity of the distributed architecture is determined in a parametric formula. Overall, the contribution of the present paper is the development of a parametric model of the wafer manufacturing systems and the development of a parametric distributed supervisory control architecture. The present results provide a ready-to-hand solution for the continuously expanding wafer production industry

Sprint mechanical and kinematic characteristics of national female track and field champions and lower-level competitors

The current study examines the sprint mechanical and kinematic characteristics between national female track and field champions (NC) and lower-level female competitors (LL). Sixteen female athletes (8 National Champions, 8 Lower-level competitors) participated in this investigation. The testing procedures consisted of two maximal 30-m sprints. The velocity-time data, captured by three high-speed cameras, was used to calculate the variables of the horizontal F-v profile (theoretical maximal values of force [F0], velocity [V0], power [Pmax], the proportion of the theoretical maximal effectiveness of force application in the antero-posterior direction [RFmax], the rate of decrease in the ratio of horizontal force [DRF]) and essential kinematics characteristics. The NC female athletes showed higher values for Pmax (t = 3.26, p = 0.006), V0 (t = 6.27, p = 0.000) and RFmax (t = 2.58, p = 0.022) compared to LL female competitors. No statistical differences were observed for F0 (t = 1.027, p = 0.32) and DRF (t = 0.917, p = 0.375). Mean running velocity, step frequency and contact time were higher in all but one (0-5 m) 5-m distance intervals of the 30-m sprint. No differences were found in the mean step length, relative step length and flight time in the intervals (0-5, 5-10, 10-15, 15-20, 20-25, and 25-30 m). The faster female athletes in our study demonstrated the capacity to reach superior running velocities, develop larger horizontal forces at higher velocities, apply more effectively the force on the ground in the acceleration phase, show higher values of step frequencies and spent less time in contact with the ground than slower athletes. © 2021, Editura Universitatii din Pitesti. All rights reserved

Supervisor Design for a Pressurized Reactor Unit in the Presence of Sensor and Actuator Faults

The preservation of the efficient functionality of a pressurized reactor unit in the presence of faults is the aim of the present paper. To satisfy this aim, a distributed supervisory control scheme, considering the possibility of system faults, was designed. Towards this aim, the models of the subsystems of the total pressurized reactor unit in the presence of sensor and actuator faults are developed, using finite deterministic automata. This is the first contribution of the paper. The desired performance of the unit was formulated in the form of rules guaranteeing the desired behavior of a pressurize–depressurize cycle and safety specifications. The rules were translated to six desired regular languages. The realization of these languages, in the form of supervisor automata, was accomplished. This is the second contribution of the paper. A modular supervisory design scheme, towards safety and tolerance in the presence of faults, was proposed and realized, and the properties of the proposed supervisors and the controlled automaton were proven. This is the third contribution of the paper. The complexity of each supervisor was computed. The efficiency of the supervisory design scheme was illustrated through simulations. A PLC implementation of the derived supervisors was proposed. The derived supervisors are suitable for implementation as function blocks

Metaheuristic Procedures for the Determination of a Bank of Switching Observers toward Soft Sensor Design with Application to an Alcoholic Fermentation Process

The present work focused on the development of soft sensors for single-input single-output (SISO) nonlinear dynamic systems with unknown physical parameters using a switching observer design. Toward the development of more accurate soft sensors, as compared with hard sensors, an extended design methodology for the determination of a bank of operating points satisfying the dense web principle was proposed, where for the determination of the bank of operating points and the observer parameters, a metaheuristic procedure was developed. To validate the results of the metaheuristic algorithm, the case of an alcoholic fermentation process was studied as a special case of the present approach. For the nonlinear model of the process, an observer-based soft sensor was developed using the metaheuristic procedure. First, the accuracy of the linear approximant of the process with respect to the original nonlinear model was investigated. Second, the I/O reconstructability of the linear approximant was verified. Third, based on the linear approximant, an observer was designed for the estimation of the non-measurable variable. Fourth, considering that the observer is designed upon the linear approximant, the linear approximant model parameters are derived through identification, for different operating points, upon the nonlinear model. Fifth, the observers corresponding to the different operating points, constitute a bank of observers. The design was completed using a data-driven rule-based system, performing stepwise switching between the observers of the bank. The efficiency of the proposed metaheuristic algorithm and the performance of the switching scheme were demonstrated through a series of computational experiments, where it was observed that the herein-proposed approach was more than two orders of magnitude more accurate than traditional single-step approaches of transition from one operating point to another

Modular Supervisory Control for the Coordination of a Manufacturing Cell with Observable Faults

In the present paper, a manufacturing cell in the presence of faults, coming from the devices of the process, is considered. The modular modeling of the subsystems of the cell is accomplished using of appropriate finite deterministic automata. The desired functionality of the cell as well as appropriate safety specifications are formulated as eleven desired languages. The desired languages are expressed as regular expressions in analytic forms. The languages are realized in the form of appropriate general type supervisor forms. Using these forms, a modular supervisory design scheme is accomplished providing satisfactory performance in the presence of faults as well guaranteeing the safety requirements. The aim of the present supervisor control scheme is to achieve tolerance of basic characteristics of the process coordination to upper-level faults, despite the presence of low-level faults in the devices of the process. The complexity of the supervisor scheme is computed

Expression of proto-oncogene c-Myc in patients with urinary bladder transitional cell carcinoma

Background: C-Myc is a proto-oncogene located on human chromosome 8. It encodes a transcriptional factor which regulates the expression of approximately 10% to 15% of human genes, playing a crucial role in cell growth, differentiation, cellular metabolism, apoptosis, and cell transformation. The aim of this study is to correlate the expression of c-Myc in patients suffering from urinary bladder transitional cell carcinoma with tumor grade, stage, and lymph node metastases. Materials and methods: Formalin-fixed, paraffin-embedded tissue samples were obtained from 54 consecutive patients who underwent transurethral resection of bladder tumor or radical cystectomy (RC) as treatment for urinary bladder transitional cell carcinoma. Immunohistochemistry was performed using c-Myc monoclonal antibody and c-Myc expression was then analyzed for correlation with tumor stage, grade, and lymph node metastases. Results: From a total of 54 patients, 42 (77.8%) had c-Myc positive staining and 12 (22.2%) were c-Myc negative. In the c-Myc positive group, 28 patients (66.7%) had low grade tumors and 33 (78.6%) presented with non-muscle-invasive disease (p<0.05). In the c-Myc negative group, 10 patients (83.3%) had high-grade disease and 8 (66.7%) presented with muscle-invasive disease (p< 0.05). Lymph node metastases were evaluated in 17 patients who underwent RC. Of these, 5 had lymph node metastases, 4 of whom had c-Myc negative staining (p<0.05). Conclusions: In our study, c-Myc negative staining was associated with higher grade and higher stage disease. On the contrary, most c-Myc positive tumors were low grade and non-muscle-invasive disease. In patients who underwent RC, c-Myc negative staining was associated with lymph node metastases. © 2021 S. Karger AG. All rights reserved

Saddleback syndrome in European sea bass Dicentrarchus labrax (Linnaeus, 1758) : anatomy, ontogeny and correlation with lateral-line, anal and pelvic fin abnormalities

This study focused on the anatomy and ontogeny of saddleback syndrome (SBS) in reared European sea bass. The abnormality was detected at an unusually high frequency (12-94%) during a routine quality control in a commercial hatchery. Anatomically the abnormality was mainly characterized by the loss of 1-5 hard spines and severe abnormalities of the proximal pterygiophores (anterior dorsal fin), size reduction of a few lepidotrichia, missing lepidotrichia and/or lepidotrichia of poor ossification (posterior dorsal fin). SBS was significantly correlated with abnormalities of the anal and pelvic fins in all the examined populations. Moreover, in juvenile fish, SBS was significantly correlated with an abnormal lack of sectors of the lateral line. The examination of early larval samples revealed that SBS was ontogenetically associated with severe abnormalities of the primordial marginal finfold, which developed at the flexion stage (ca 8.5-11.0 mm SL). Histologically, these abnormalities were associated with extensive epidermal erosion. The results are discussed in respect of the critical ontogenetic period and the possible causative factors of SBS in European sea bass. It is suggested that causative factors acted during a wide ontogenetic period including flexion and metamorphosis phases