Evaluation of the determinism of the actuator sensor interface (ASI) on programmable logic controllers (PLC), personal computers (PC) and real-time operating systems (RTOS)

The purpose of this study was to evaluate the determinism of the AS-lnterface network and the 3 main families of control systems, which may use it, namely PLC, PC and RTOS. During the course of this study the PROFIBUS and Ethernet field level networks were also considered in order to ensure that they would not introduce unacceptable latencies into the overall control system. This research demonstrated that an incorrectly configured Ethernet network introduces unacceptable variable duration latencies into the control system, thus care must be exercised if the determinism of a control system is not to be compromised. This study introduces a new concept of using statistics and process capability metrics in the form of CPk values, to specify how suitable a control system is for a given control task. The PLC systems, which were tested, demonstrated extremely deterministic responses, but when a large number of iterations were introduced in the user program, the mean control system latency was much too great for an AS-I network. Thus the PLC was found to be unsuitable for an AS-I network if a large, complex user program Is required. The PC systems, which were tested were non-deterministic and had latencies of variable duration. These latencies became extremely exaggerated when a graphing ActiveX was included in the control application. These PC systems also exhibited a non-normal frequency distribution of control system latencies, and as such are unsuitable for implementation with an AS-I network. The RTOS system, which was tested, overcame the problems identified with the PLC systems and produced an extremely deterministic response, even when a large number of iterations were introduced in the user program. The RTOS system, which was tested, is capable of providing a suitable deterministic control system response, even when an extremely large, complex user program is required.

Does the provision of full day care improve the quality of life for children and their parents

This study sought to explore and examine if the provision of full day care improves the quality of life for children and their parents. Owing to the effects of the Celtic Tiger, life in Ireland has changed considerably over the past five to ten years. Because of the booming economy there are now 60.8% of women employed in the workforce. This means many changes for children, parents and families. Findings in the literature review are based on international studies. The researcher utilised both qualitative and quantitative research methodologies for the study. She interviewed 31 respondents; 27 childcare managers; 3 politicians and the chairperson of a childcare committee. Furthermore, 325 questionnaires were completed in a survey by working parents in the statutory and voluntary sectors in and around Sligo town and in two childcare facilities in Letterkenny, Co. Donegal. Babies as young as 4 months are being cared for in childcare facilities from 6.45am until 6.pm daily, 5 days per week. Some children are spending up to 11 hours per day in childcare facilities. The study has not categorically concluded that full day care is either positive or negative for children. Childcare facilities are providing good quality childcare encompassing various services; however, 25 out of 27 childcare managers reported to the researcher that they would not leave their child in full day care. Parents are finding it difficult to manage work life balance. Health dominated quality of life issues. Two hundred and thirty five (235) parents reported being stressed. The study also found that 315 working parents feel that the government is not doing enough to support working parents. On a positive note, 241 parents said they are happy in general with the quality of life for them, their family and their children. In addition, the researcher has identified a number of recommendations for future changes in policy and further study.