A new mathematical model for single machine batch scheduling problem for minimizing maximum lateness with deteriorating jobs

This paper presents a mathematical model for the problem of minimizing the maximum lateness on a single machine when the deteriorated jobs are delivered to each customer in various size batches. In reality, this issue may happen within a supply chain in which delivering goods to customers entails cost. Under such situation, keeping completed jobs to deliver in batches may result in reducing delivery costs. In literature review of batch scheduling, minimizing the maximum lateness is known as NP-Hard problem; therefore the present issue aiming at minimizing the costs of delivering, in addition to the aforementioned objective function, remains an NP-Hard problem. In order to solve the proposed model, a Simulation annealing meta-heuristic is used, where the parameters are calibrated by Taguchi approach and the results are compared to the global optimal values generated by Lingo 10 software. Furthermore, in order to check the efficiency of proposed method to solve larger scales of problem, a lower bound is generated. The results are also analyzed based on the effective factors of the problem. Computational study validates the efficiency and the accuracy of the presented model

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Minimizing total weighted tardiness for the single machine scheduling problem with dependent setup time and precedence constraints

This paper tackles the single machine scheduling problem with dependent setup time and precedence constraints. The primary objective of this paper is minimization of total weighted tardiness. Since the complexity of the resulted problem is NP-hard we use metaheuristics method to solve the resulted model. The proposed model of this paper uses genetic algorithm to solve the problem in reasonable amount of time. Because of high sensitivity of GA to its initial values of parameters, a Taguchi approach is presented to calibrate its parameters. Computational experiments validate the effectiveness and capability of proposed method

Management Science Letters Two models for the generalized assignment problem in uncertain environment

The generalized assignment problem (GAP) is a unique extended form of the Knapsack problem, which is tremendously practical in optimization fields. For instance, resource allocation, sequencing, supply chain management, etc. This paper tackles the GAP in uncertain environment in which the assignment costs and capacity of agents are fuzzy numbers. Two models are presented for this problem and a novel hybrid algorithm is offered using simulated annealing (SA) method and max-min fuzzy in order to obtain near optimal solution. Computational experiments validate the efficiency of proposed method

Two models for the generalized assignment problem in uncertain environment

The generalized assignment problem (GAP) is a unique extended form of the Knapsack problem, which is tremendously practical in optimization fields. For instance, resource allocation, sequencing, supply chain management, etc. This paper tackles the GAP in uncertain environment in which the assignment costs and capacity of agents are fuzzy numbers. Two models are presented for this problem and a novel hybrid algorithm is offered using simulated annealing (SA) method and max-min fuzzy in order to obtain near optimal solution. Computational experiments validate the efficiency of proposed method

A branch and bound for single machine stochastic scheduling to minimize the maximum lateness

This paper studies the problem of single machine stochastic scheduling with random processing times, deterministic due dates and an independent setup time. The jobs are also deteriorated based on the position, which their processes are done. The objective function is to find a schedule of jobs, which minimizes the expected value of maximum lateness. A branch and bound scheme is presented to solve the problem analytically and a simulated annealing metaheuristic (SA) is also provided for solving the problem in larger scales. Computational experiments demonstrate that the proposed SA is capable of finding near optimal solutions with very low gap

On the Effects of Structural Coupling on Piezoelectric Energy Harvesting Systems Subject to Random Base Excitation

The current research investigates the novel approach of coupling separate energy harvesters in order to scavenge more power from a stochastic point of view. To this end, a multi-body system composed of two cantilever harvesters with two identical piezoelectric patches is considered. The beams are interconnected through a linear spring. Assuming a stochastic band limited white noise excitation of the base, the statistical properties of the mechanical response and those of the generated voltages are derived in closed form. Moreover, analytical models are derived for the expected value of the total harvested energy. In order to maximize the expected generated power, an optimization is performed to determine the optimum physical and geometrical characteristics of the system. It is observed that by properly tuning the harvester parameters, the energy harvesting performance of the structure is remarkably improved. Furthermore, using an optimized energy harvester model, this study shows that the coupling of the beams negatively affects the scavenged power, contrary to the effect previously demonstrated for harvesters under harmonic excitation. The qualitative and quantitative knowledge resulting from this analysis can be effectively employed for the realistic design and modelling of coupled multi-body structures under stochastic excitations

Antimalarial evaluation of selected medicinal plant extracts used in Iranian traditional medicine

Objective(s): In an attempt to discover new natural active extracts against malaria parasites, the present study evaluated the antiplasmodial properties of selected plants based on Iranian traditional medicine. Materials and Methods: Ten plant species found in Iran were selected and collected based on the available literature about the Iranian traditional medicine. The methanolic extracts of these plants were investigated for in vitro antimalarial properties against chloroquine-sensitive (3D7) and multi-drug resistant (K1) strains of Plasmodium falciparum. Their in vivo activity against Plasmodium berghei infection in mice was also determined. Cytotoxicity tests were carried out using the Raji cells line using the MTT assay. The extracts were phytochemically screened for their active constituents. Results: According to the IC50 and selectivity index (SI) values, of the 10 selected plant species, Citrullus colocynthis, Physalis alkekengi, and Solanum nigrum displayed potent in vitro antimalarial activity against both 3D7 and K1 strains with no toxicity (IC50= 2.01-18.67 µg/ml and SI=3.55 to 19.25).  Comparisons between treated and untreated control mice showed that the mentioned plant species reduced parasitemia by 65.08%, 57.97%, and 60.68%, respectively.  The existence of antiplasmodial compounds was detected in these plant extracts. Conclusion: This was the first study to highlight the in vitro and in vivo antiplasmodial effects of             C. colocynthis, P. alkekengi, and S. nigrum in Iran. Future studies can use these findings to design further biological tests to identify the active constituents of the mentioned plant species and clarify their mechanism of action

Effect of dietary fish oil and corn oil on blood biochemical factors in diabetic Rat

Background: The potential role of omega – 3 (ω-3) and omega-6 (ω-6) fatty acids on blood biochemical factors are in interest and controversy. Some experiences showed that omega – 3 (ω-3) and omega-6 (ω-6) fatty acids have a potential effect on triglyceride, LDL-cholesterol, HDL-cholesterol and total cholesterol levels in diabetes mellitus. Methods: Male rats were divided into four groups (one normal group and three diabetic groups). Induction of diabetes was done by streptozotocin [50mg/kg, s.c. (STZ)]. In diabetic groups, one group was Control, received STZ alone, and the other diabetic groups were fed with fish oil or corn oil for 8 weeks after 4 weeks of induction of diabetes. Plasma glucose, total cholesterol, triglyceride, LDL- choleserol and HDL-cholesterol were measured at 4 and 8 weeks after intervention. Results: Fish oil and corn oil diets had an inhibitory effect on increased plasma glucose in diabetic rat by 46.8% and 40.7%, respectively. Diabetic rats in the control group demonstrated increased plasma total cholesterol, triglyceride and LDL-cholesterol levels, but plasma total cholesterol, triglyceride and LDL-cholesterol levels were significantly decreased and HDL-cholesterol level was increased by both diets in interventional groups. Conclusion: Corn oil and fish oil supplementation have a role on plasma glucose and lipid profile in diabetic rats. To understand the functional mechanisms of these diets, further studies remain to be accomplished