k-Çinli postacı dengeleme problemi üzerine.

In this thesis, we consider a k-Chinese Postmen Problem with the objective of minimizing total squared workloads. Our aim is to balance the workloads of the postmen, while maintaining low total workload. We develop an efficient subtour elimination constraint and incorporate it to our integer program. We develop exact and approximate solution procedures that run in exponential and polynomial time respectively. The results of our computational experiment reveal the satisfactory behaviors of our algorithms in terms of solution speed and solution quality.M.S. - Master of Scienc

New heuristics for the balanced k-Chinese postmen problem

In this study, we consider a directed k-Chinese postmen problem that aims to balance the costs of the postmen, while maintaining the total cost as small as possible. We formulate the problem as a pure integer nonlinear programming model. We propose three solution algorithms that use efficient incorporation of the heuristic subtour elimination constraints. Our computational results have revealed the satisfactory performances of our heuristic solution algorithms

Aldevron accelerates growth using operations research in biomanufacturing

In the biomanufacturing industry, production and planning decisions are often challenging because of batch-to-batch variability and uncertainty in the production yield, quality, cost, and lead times. To improve biomanufacturing efficiency, a multidisciplinary team of researchers collaborated over five years to develop a portfolio of decision support tools. The tools developed provide a data-driven, operations research–based approach to reduce biomanufacturing costs and lead times. These decision support tools comprise multiple deterministic and stochastic optimization models to optimize production and planning decisions. To optimize production decisions related to fermentation and protein purification, optimization tools were developed to provide a decision support mechanism that links the underlying biological and chemical processes with business risks and financial trade-offs. To optimize planning decisions, interactive scheduling and capacity planning tools were developed to enable efficient use of expensive and limited resources. Although developed in collaboration with Aldevron, these tools address common industry challenges, and they have been shared with a wider industry community through working group sessions

Ability of Emergency Physicians to Detect Early Ischemic Changes of Acute Ischemic Stroke on Cranial Computed Tomography

Objective: The objective of this study was to evaluate the ability of emergency physicians (EPs) to diagnose early ischemic changes due acute ischemic stroke on cranial computed tomography (CT). Subjects and Methods: Three EPs interpreted CT scans obtained within 3 h of symptom onset in 50 patients with acute stroke. The CT scans were interpreted by the EPs and compared to official neuroradiologist reports as a gold standard. kappa statistics were calculated to determine agreement among the three readers. Sensitivities and specificities were analyzed for each reader. Results: The EPs' sensitivities were 50, 45.5, and 45.5%, and specificities were 64.3, 82.1, and 64.3%, respectively. Focal parenchymal hypodensity was the criterion for which the EPs were the most sensitive (77.3%). The ability of EPs to recognize early ischemic changes on CT scans in acute ischemic stroke was moderate based on sensitivities. Conclusion: Based on this study, EPs must be trained especially for recognizing early ischemic changes in acute ischemic stroke to improve their accuracy of interpretation. Copyright (C) 2012 S. Karger AG, Base

Empagliflozin in Patients with Chronic Kidney Disease

Background The effects of empagliflozin in patients with chronic kidney disease who are at risk for disease progression are not well understood. The EMPA-KIDNEY trial was designed to assess the effects of treatment with empagliflozin in a broad range of such patients. Methods We enrolled patients with chronic kidney disease who had an estimated glomerular filtration rate (eGFR) of at least 20 but less than 45 ml per minute per 1.73 m(2) of body-surface area, or who had an eGFR of at least 45 but less than 90 ml per minute per 1.73 m(2) with a urinary albumin-to-creatinine ratio (with albumin measured in milligrams and creatinine measured in grams) of at least 200. Patients were randomly assigned to receive empagliflozin (10 mg once daily) or matching placebo. The primary outcome was a composite of progression of kidney disease (defined as end-stage kidney disease, a sustained decrease in eGFR to < 10 ml per minute per 1.73 m(2), a sustained decrease in eGFR of & GE;40% from baseline, or death from renal causes) or death from cardiovascular causes. Results A total of 6609 patients underwent randomization. During a median of 2.0 years of follow-up, progression of kidney disease or death from cardiovascular causes occurred in 432 of 3304 patients (13.1%) in the empagliflozin group and in 558 of 3305 patients (16.9%) in the placebo group (hazard ratio, 0.72; 95% confidence interval [CI], 0.64 to 0.82; P < 0.001). Results were consistent among patients with or without diabetes and across subgroups defined according to eGFR ranges. The rate of hospitalization from any cause was lower in the empagliflozin group than in the placebo group (hazard ratio, 0.86; 95% CI, 0.78 to 0.95; P=0.003), but there were no significant between-group differences with respect to the composite outcome of hospitalization for heart failure or death from cardiovascular causes (which occurred in 4.0% in the empagliflozin group and 4.6% in the placebo group) or death from any cause (in 4.5% and 5.1%, respectively). The rates of serious adverse events were similar in the two groups. Conclusions Among a wide range of patients with chronic kidney disease who were at risk for disease progression, empagliflozin therapy led to a lower risk of progression of kidney disease or death from cardiovascular causes than placebo