Scheduling and pricing of services to minimise CO2 emissions of delivery vehicles

Previous research found that minimising emissions often conflicts with maximising profit in service delivery. In this study, we consider a service scheduling problem and propose a new approach to the problem which applies low-emission vehicle scheduling techniques with dynamic pricing to reduce CO2 emissions and maximise profit. Incentives are included in the service prices to influence the customer’s choice in order to reduce CO2 emissions. To help the company determining the incentives, our approach solves the problem in two phases. The first phase solves vehicle scheduling models with the objective of minimising CO2 emissions and the second phase solves a dynamic pricing model to maximise profit. This approach is tested through numerical experiments

Decision support system for green real-life field scheduling problems

© Springer International Publishing AG 2017. A decision support system is designed in this paper for supporting the adoption of green logistics within scheduling problems, and applied to real-life services cases. In comparison to other green logistics models, this system deploys time-varying travel speeds instead of a constant speed, which is important for calculating the CO 2 emission accurately. This system adopts widely used instantaneous emission models in literature which can predict second-by-second emissions. The factors influencing emissions in these models are vehicle types, vehicle load and traffic conditions. As vehicle types play an important role in computing the amount of emissions, engineers’ vehicles’ number plates are mapped to specified emission formulas. This feature currently is not offered by any commercial software. To visualise the emissions of a planned route, a Heat Map view is proposed. Furthermore, the differences between minimising CO 2 emission compared to minimising travel time are discussed under different scenarios. The field scheduling problem is formulated as a vehicle routing and scheduling problem, which considers CO 2 emissions in the objective function, heterogeneous fleet, time window constraints and skill matching constraints, different from the traditional time-dependent VSRP formulation. In the scheduler, this problem is solved by metaheuristic methods. Three different metaheuristics are compared. They are Tabu search algorithms with random neighbourhood generators and two variants of Variable Neighbourhood search algorithms: variable neighbourhood descent (VND) and reduced variable neighbourhood search (RVNS). Results suggest that RVNS is a good trade-off between solution qualities and computational time for industrial application

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Water injection performance analysis and fine potential tapping Countermeasures in heterogeneous reservoir

After the heterogeneous reservoir enters the middle and late stages of development, the problems due to water injection will become increasingly prominent. However, the requirements for water injection in reservoir development are also increasing. So how do we solve this big problem? And how to scientifically manage water injection wells, promote oil with water, improve water displacement efficiency, and make the reservoir enter a benign development state? First of all, we need to firmly remember the idea of “water well first, pay equal attention to oil and water”, lock the key points of water injection, and comprehensively improve the water injection management level from the aspects of surface, wellbore and underground, so as to consolidate the foundation of stable oil reservoir production

A time-varying lot size method for the economic lot scheduling problem with shelf life considerations

Most studies on the economic lot scheduling problem with shelf life considerations adopt the common cycle approach which usually gives a result with high cost. Basic period method has been applied to this problem recently resulting in a lower cost. This paper takes a time-varying lot size approach. Two models are formulated to optimise the production schedule for any given production sequence, one assuming that production of each product starts only when the inventory of this product becomes zero, and the other relaxing this restriction. To generate production sequences, we use an existing heuristic and also develop a new heuristic. Numerical experiments on a benchmark problem show that at all the utilisation levels tested the new method outperforms previous methods. Further experiments show that the production frequencies for the products, production sequence and a less restricted scheduling model all contribute to the low production cost. [Received: 22 August 2006; Revised: 28 October 2007; Accepted: 12 December 2007]economic lot scheduling; shelf life; time-varying lot sizes; production sequences; sequencing.

Green vehicle routing and dynamic pricing for scheduling on-site services

In this paper, we study a problem where a company sends engineers with vehicles to customer sites to provide services. Customers request the service through a website or by calling a call centre and the company needs to allocate the service tasks to time windows and decide on how to schedule these jobs to their vehicles. We propose a new approach to this problem which applies low-emission vehicle routing techniques with dynamic pricing to reduce CO2 emissions and maximise profit. When a customer requests a service, the company will provide the customer with different service time-window options and their corresponding prices. Prices are differentiated to influence the customer’s choice. To help the company in determining the prices, our approach solves the problem in two phases. The first phase solves a time-dependent vehicle routing model with the objective of minimising CO2 emissions for each of the time window options and the second phase solves a dynamic pricing model to determine the service prices for these options to maximise profit. Metaheuristic methods are applied for real-life business applications which enable the solution framework to be applied online where shorter computational time is required. The approach is tested through numerical experiments. Results show that dynamic pricing leads to a reduction in CO2 emissions and an improvement in profit.</p

Long-Term Over-Expression of Neuropeptide Y in Hypothalamic Paraventricular Nucleus Contributes to Adipose Tissue Insulin Resistance Partly via the Y5 Receptor.

Intracerebroventricular injection and overexpression of Neuropeptide Y (NPY) in the paraventricular nucleus (PVN) has been shown to induce obesity and glucose metabolism disorder in rodents; however, the underlying mechanisms are still unclear. The aim of this study was to investigate the mechanism contributing to glucose metabolic disturbance induced by NPY. Recombinant lentiviral NPY vectors were injected into the PVN of rats fed a high fat (HFD) or low-fat diet. 8 weeks later, in vivo intravenous glucose tolerance tests and euglycemic-hyperinsulinemic clamp revealed that insulin resistance of adipose tissue were induced by NPY overexpression with or without HFD. NPY increased food intake, but did not change blood glucose, glycated hemoglobin A1c (HbA1c) or lipid levels. However, NPY decreased the expression of pGSK3β, PI3K p85 and pAKTSer473 in adipose tissue of rats. In vitro, 3T3-L1 adipocytes were treated with NPY, NPY Y1 and Y5 receptor antagonists. Glucose consumption and 2-deoxy-D-[3H] glucose uptake were partly inhibited by NPY, while a decrease in PI3K-AKT pathway signaling and a decreased expression of pGSK3α and pGSK3β were observed. Nevertheless, a Y5 receptor antagonist (L-152,804) reversed the effects of NPY on glucose uptake and consumption. These data suggest that long-term over-expression of NPY in PVN contributes to the establishment of adipose tissue insulin resistance, at least partly via the Y5 Receptor