Peak Electricity Demand Control of Manufacturing Systems by Gale-Shapley Algorithm with Discussion on Open Innovation Engineering

The peak power of the manufacturing systems can increase electricity costs and reduce the use of renewable energy suppliers. The power of the machining processes depends on the processing time of the operations. Then, the allocation of the power to the machines of a manufacturing system controls the processing time of the manufacturing operations. An efficient allocation model can reduce the peak power, keeping the throughput performance level. This paper proposes a game theory to allocate the power to the machines including the dependence of the processing time from the power allocated. The game model uses the Gale-Shapley algorithm that forms couples of under and overloaded machines. Then, each couple exchanges the power from the underloaded to overloaded machines. The model considers the global workload and the jobs in queue for each machine. A simulation model tests the proposed method compared to a benchmark where each machine works with fixed power. The simulation results show how the model can improve the performance of the manufacturing system in several conditions tested. In particular, the main benefits can be obtained when the manufacturing system has high or medium utilization or the uncertainty affects the processing time.

Effects of factors of informal care on the utilization of social care insurance benefits: A cross-sectional study

Background: Presently in Germany, as there is a shortage of nursing staff, informal caregivers have become highly relevant. Because they often deal with care related burden, legislation was passed to improve caregivers’ situations by offering more supports. Nonetheless, a considerable percentage of caregivers do not utilize it. Methods: Data was collected in Saxony (Germany) from November 2019 to December 2019 by using an online survey and a postal survey (cross-sectional study design; n= 1,716). For analysis bivariate logistic regression (forward method LR, α≤0.05) was performed. Results: The average age of the sample was 61.9 years, 52.9% were female and 45.7% male. Results indicate a medium utilization of care insurance services. Considerable associations were time spent on care and utilization of care allowance (OR: 1.77), such as duration of care degree and utilization of residential care services (OR: 1.88) and substitute care (OR: 1.81). Conclusions: Informal caregivers putting intensive effort into care do tend to utilize services. The resulting questions of why newer informal caregivers do not tend to utilize services and why there is a medium utilization among all caregivers implies that people need to gain better access to services independently of care factors.

Gauging potential demand for new events

Purpose – The purpose of this paper is to gauge potential interest in equestrian events for a proposed multi-use international horse park. Design/methodology/approach – Multi-stage, mixed methods were employed, including interviews with industry professionals at competing horse parks, a survey of potential visitors and an economic impact analysis. Findings – Both industry professionals and equine tourists felt that the proposed facility had the potential to succeed with an international horse park especially as it already has a strong equine culture. Potential visitors already possess a high awareness of city as an equestrian tourist destination, and the majority said they would visit the new facility to take part in, or watch equine events. At medium utilization, the facility has the potential to attract 225 events to the park annually, attracting approximately 428,000 attendees. This would have an annual spending impact of about US$38 million, generating 575 full-time jobs. Practical implications – Based on the results, a number of recommendations were made to the local chamber of commerce by the researchers, but the key suggestion was that stakeholders in Aiken proceed cautiously with a phased approach to development. Originality/value – Despite the growing body of literature related to measuring the impacts of events, very few researchers have looked at the feasibility of new events, and the need to measure potential demand for a new facility. This paper is therefore unique and of great value to both researchers and practitioners.

Performance Analysis and Evaluation of IEEE 802.11E MAC in WLANs with Hidden Stations and Multimedia Applications

Recently there have been considerable interests focusing on the performance evaluation of IEEE 802.11e Medium Access Control (MAC) protocols, which were proposed for supporting differentiated quality of services in wireless local area networks (WLANs). Heterogeneous traffic generated by wireless multimedia applications and hidden stations arisen from the wireless transmission power constraints have significant impact on the performance of MAC protocols. This study performs extensive simulation experiments and conducts comprehensive performance evaluation of the IEEE 802.11e Enhanced Distributed Channel Access (EDCA) protocol in WLANs in the presence of hidden stations and heterogeneous traffic. For this purpose, non-bursty Poisson, bursty ON/OFF, and fractal-like self-similar processes with high variability are used to model and generate heterogeneous network traffic. The performance results have shown that this protocol is able to achieve differentiated throughput, access delay, packets loss probability, and medium utilization. However, the hidden stations can degrade the throughput and medium utilization as well as increase greatly the medium access delay, packets loss probability, and collision ratio under heterogeneous traffic.