Toward a Holistic Delay Analysis of EtherCAT Synchronized Control Processes

This paper analyzes the end-to-end delay of EtherCAT-based control processes that use the events of message frames and global clock for synchronized operation. With the end-to-end delay defined as the time interval between the start of a process cycle and the actual input or output, we develop a holistic delay model for control processes in EtherCAT, by taking into account the time for in-controller processing, message delivery, and slave-local handling. Based on the measurements from a real EtherCAT control system, we discuss the average and deviation of the process delay as we vary the number of slaves and process cycle time. The experiment results show that the output delays are mainly increased by the average controller delay, whereas the input delays are more affected by the deviation rather than the average of the controller delay. Our in-depth analysis on the controller reveals that DMA time chiefly enlarges the controller delay for increasing number of slaves, while task release jitter is the main cause of the increased delay for longer cycle time. The presented delay model and evaluation results can be essentially used for the design of EtherCAT-based automation that requires highly synchronized operations, such as for coordinated motion and high-precision data sensing

Formal Modeling and Verification of Motor Drive Software for Networked Motion Control Systems

Abstract: This paper presents a model-based approach to the design and verification of motor drive software for networked motion control systems. We develop a formal model for an Ethernetbased motion system, where, using timed automata, we describe the concurrent and synchronized behaviors of the components, i.e., motion controller, motor drives, and communication links. The drive, in particular, is modeled in enough detail to accurately reflect the software implementation used in a real drive. We use the design of multitasked drive software with fixed-priority preemptive scheduling. With UPPAAL model checking, we verify the precision and accuracy of the rendered motion in terms of the requirements on the actuation delay at each drive and the actuation deviation between different drives, respectively. The analysis results demonstrate the benefits of our model-based approach in the safety verification and design space exploration of motor drive software. We show that it is possible to verify deadlock freeness and real-time schedulability in an early design phase. And, for varying number of drives and size of messages, we can successfully determine the combination of task periods that leads to the best precision and accuracy

Clinical Significance of Annexin A1 Expression in Breast Cancer

Purpose: The expression of Annexin A1 (ANXA1) is known to be reduced in human breast cancer; however, the role of ANXA1 expression in the development of breast cancer remains unclear. In this study, we determined the relationship between the expression features of ANXA1 and the prognostic factors of breast cancer. Methods: Human breast tissues were obtained from patients specimens who had undergone breast surgery or core needle biopsies. The patterns of ANXA1 expression were analyzed by immunohistochemical staining in relation to histopathological diagnosis, clinical characteristics and outcomes. Results: One hundred eighty-two cases were included and the mean age of the patients was 46.34 ± 11.5 years. A significant loss of ANXA1 expression was noted in both ductal carcinoma in situ (DCIS) and invasive carcinomas compared to normal breast tissues (p<0.001) and benign breast diseases (p<0.001). There was a significan

Comparative efficacy and safety of infliximab and vedolizumab therapy in patients with inflammatory bowel disease : a systematic review and meta-analysis

Background and aims There are limited comparative data for infliximab and vedolizumab in inflammatory bowel disease patients. Methods We conducted a systematic review and meta-analysis to compare the efficacy and safety of infliximab and vedolizumab in adult patients with moderate-to-severe Crohn's disease or ulcerative colitis. Results We identified six eligible Crohn's disease and seven eligible ulcerative colitis trials that randomised over 1900 participants per disease cohort to infliximab or vedolizumab. In the Crohn's disease and ulcerative colitis cohorts, infliximab yielded better efficacy than vedolizumab for all analysed outcomes (CDAI-70, CDAI-100 responses, and clinical remission for Crohn's disease and clinical response and clinical remission for ulcerative colitis) during the induction phase, with non-overlapping 95% confidence intervals. In the maintenance phase, similar proportions of infliximab- or vedolizumab-treated patients achieved clinical response, clinical remission, or mucosal healing in both Crohn's disease and ulcerative colitis. For the safety outcomes, rates of adverse events, serious adverse events, and discontinuations due to adverse events were similar in infliximab- and vedolizumab-treated patients in both diseases. The infection rate was higher in infliximab for Crohn's disease and higher in vedolizumab when treating patients with ulcerative colitis. There was no difference between the treatments in the proportions of patients who reported serious infections in both indications. Conclusions Indirect comparison of infliximab and vedolizumab trials in adult patients with moderate-to severe Crohn's disease or ulcerative colitis demonstrated that infliximab has better efficacy in the induction phase and comparable efficacy during the maintenance phase and overall safety profile compared to vedolizumab.Peer reviewe

OPC-UA Agent for Legacy Programmable Logic Controllers

Open platform communications (OPC) unified architecture (UA) is a communication standard increasingly used in industrial automation systems to enable the exchanging of control and management data between distributed entities. This paper proposes the design of an OPC-UA agent to enable UA information service and client functionalities in legacy programmable logic controllers (PLCs). The agent runs on a separate machine connected to the PLC using a dedicated link and maintains shared memory for certain variables in the PLC. Based on the periodically synchronized variables, the agent services the OPC-UA information model and executes client function blocks on behalf of the PLC. One important design feature is the remote procedure call of IEC 61131-3-based function blocks using synchronized variables. This allows the standard OPC-UA client functions to be used in existing PLCs which only support numeric types and do not support strings or complex structures. To validate the proposed design, we implement an agent prototype and demonstrate the successful monitoring and control of an industrial robot controller via OPC-UA. Through experiments, we evaluate the performance of UA functions in terms of the latency of read services for an increasing number of items. The evaluation results are believed to provide useful insights into agent-based approaches for integrating legacy PLCs into the OPC-UA framework

OPC-UA Agent for Legacy Programmable Logic Controllers

Open platform communications (OPC) unified architecture (UA) is a communication standard increasingly used in industrial automation systems to enable the exchanging of control and management data between distributed entities. This paper proposes the design of an OPC-UA agent to enable UA information service and client functionalities in legacy programmable logic controllers (PLCs). The agent runs on a separate machine connected to the PLC using a dedicated link and maintains shared memory for certain variables in the PLC. Based on the periodically synchronized variables, the agent services the OPC-UA information model and executes client function blocks on behalf of the PLC. One important design feature is the remote procedure call of IEC 61131-3-based function blocks using synchronized variables. This allows the standard OPC-UA client functions to be used in existing PLCs which only support numeric types and do not support strings or complex structures. To validate the proposed design, we implement an agent prototype and demonstrate the successful monitoring and control of an industrial robot controller via OPC-UA. Through experiments, we evaluate the performance of UA functions in terms of the latency of read services for an increasing number of items. The evaluation results are believed to provide useful insights into agent-based approaches for integrating legacy PLCs into the OPC-UA framework