Experiments on the Node, Edge, and Arc Routing Problem

-The Node, Edge, and Arc Routing Problem (NEARP) was defined by Prins and Bouchenoua in 2004 along with the first benchmark called CBMix. The NEARP generalizes the classical Capacitated Vehicle Routing Problem (CVRP), the Capacitated Arc Routing Problem (CARP), and the General Routing Problem. It is also denoted the Mixed Capacitated General Routing Problem (MCGRP). The NEARP removes the strict and unwarranted dichotomy that previously existed in the literature between arc routing and node routing. In real applications, there are many cases where the pure node or arc routing models are not adequate. In fundamentally node-based routing applications such as newspaper delivery and communal waste management that have typically been modeled as arc routing problems in the literature, the number of points is often so large that demand aggregation is necessary. Aggregation heuristics will normally give a NEARP instance, possibly with side constraints. Hence, the NEARP is a scientifically challenging problem with high industrial relevance. In this report we present experiments with Spider, SINTEF’s industrial VRP solver, on the three NEARP benchmarks that have been published so far: CBMix, BHW, and DI-NEARP. Bach, Hasle, and Wøhlk have developed a combinatorial lower bound for the NEARP and defined the two latter benchmarks. Here, we present an experimental study with Spider on the three existing NEARP benchmarks. Upper and lower bounds are given for all instances. Three of the BHW instances have been solved to optimality. SINTEF has developed a web page for NEARP results on http://www.sintef.no/NEARP

Experiments on the Node, Edge, and Arc Routing Problem

The Node, Edge, and Arc Routing Problem (NEARP) was defined by Prins and Bouchenoua in 2004 along with the first benchmark called CBMix. The NEARP generalizes the classical Capacitated Vehicle Routing Problem (CVRP), the Capacitated Arc Routing Problem (CARP), and the General Routing Problem. It is also denoted the Mixed Capacitated General Routing Problem (MCGRP). The NEARP removes the strict and unwarranted dichotomy that previously existed in the literature between arc routing and node routing. In real applications, there are many cases where the pure node or arc routing models are not adequate. In fundamentally node-based routing applications such as newspaper delivery and communal waste management that have typically been modeled as arc routing problems in the literature, the number of points is often so large that demand aggregation is necessary. Aggregation heuristics will normally give a NEARP instance, possibly with side constraints. Hence, the NEARP is a scientifically challenging problem with high industrial relevance. In this report we present experiments with Spider, SINTEF’s industrial VRP solver, on the three NEARP benchmarks that have been published so far: CBMix, BHW, and DI-NEARP. Bach, Hasle, and Wøhlk have developed a combinatorial lower bound for the NEARP and defined the two latter benchmarks. Here, we present an experimental study with Spider on the three existing NEARP benchmarks. Upper and lower bounds are given for all instances. Three of the BHW instances have been solved to optimality. SINTEF has developed a web page for NEARP results on http://www.sintef.no/NEARP

Commentary: Opportunities for research in molecular radiotherapy

Cancer has been treated with radiopharmaceuticals for 80 years. A recent National Cancer Research Institute report from the Clinical and Translational Radiotherapy Research Working Group reviews the current status of molecular radiotherapy and has highlighted the barriers to and opportunities for increased research activities. The report recommends a number of actions to promote this field, which in the dawning age of personalized medicine and theragnostics is of increasing importance, particularly with the clinical introduction of a range of new commercial radiotherapeutics at costs in line with those seen for conventional chemotherapeutics. These recommendations recognize the importance of a multidisciplinary approach to the development of molecular radiotherapy and the particular need for investment in radiopharmacies and personalized dosimetry. There are many areas to be investigated including adaptive treatment planning, the use of radiosensitizers and translational radiation biology. Progress in these areas will result in significant patient benefit and more cost-effective use of increasingly expensive therapeutic radiopharmaceuticals. A concerted effort from the community, from funding bodies and from health service providers is now needed to address the scientific and logistical changes necessary to realize the potential offered by this currently underused treatment modality

Exact Optimization Methods for the Mixed Capacitated General Routing Problem

This thesis is about using exact optimization algorithms to solve the routing problemknown as the Mixed Capacitated General Arc Routing Problem (MCGRP) that is a generalizationof many other well known routing problems. The Mixed Capacitated RoutingProblem is a routing problem generalized by many other routing problems. The goal is tofind a an optimal set of routes servicing a set of required entities on a mixed network. Theentities being vertices, directed arcs or undirected edges.The mathematical programming model formulation developed by this thesis is a novelpath flow formulation inspired by another well known routing problem by Letchford andOukil (2011). The solution method is based on the exact optimization techniques ColumnGeneration and Branch & Price.The algorithm is implemented in the C# and using the the BCL XPRESS libraries. Acomparison has been given to the results by an exact algorithm by Bosco et al. (2012) aswell as the currently best results known in the literature.The algorithm has been tested on 158 benchmark instances, were 83 of them were solvedto optimum and 14 for the very first time. The algorithm is in addition an excellent lowerbounding algorithm giving 58 improved lower bounds for previously unsolved instances.There is still a lot of research that can be done on the MCGRP and we hope that this thesiswill motivate further research

Experiments on the Node, Edge, and Arc Routing Problem

-The Node, Edge, and Arc Routing Problem (NEARP) was defined by Prins and Bouchenoua in 2004 along with the first benchmark called CBMix. The NEARP generalizes the classical Capacitated Vehicle Routing Problem (CVRP), the Capacitated Arc Routing Problem (CARP), and the General Routing Problem. It is also denoted the Mixed Capacitated General Routing Problem (MCGRP). The NEARP removes the strict and unwarranted dichotomy that previously existed in the literature between arc routing and node routing. In real applications, there are many cases where the pure node or arc routing models are not adequate. In fundamentally node-based routing applications such as newspaper delivery and communal waste management that have typically been modeled as arc routing problems in the literature, the number of points is often so large that demand aggregation is necessary. Aggregation heuristics will normally give a NEARP instance, possibly with side constraints. Hence, the NEARP is a scientifically challenging problem with high industrial relevance. In this report we present experiments with Spider, SINTEF’s industrial VRP solver, on the three NEARP benchmarks that have been published so far: CBMix, BHW, and DI-NEARP. Bach, Hasle, and Wøhlk have developed a combinatorial lower bound for the NEARP and defined the two latter benchmarks. Here, we present an experimental study with Spider on the three existing NEARP benchmarks. Upper and lower bounds are given for all instances. Three of the BHW instances have been solved to optimality. SINTEF has developed a web page for NEARP results on http://www.sintef.no/NEARP

Volume status and diuretic therapy in systolic heart failure and the detection of early abnormalities in renal and tubular function

Objectives This study sought to determine the pharmacodynamic effect of modulation of volume status by withdrawal and reinstitution of diuretic treatment on markers of renal and tubular function. Background Decreased renal perfusion and increased congestion are associated with renal dysfunction in patients with heart failure. Methods In this study, 30 patients with chronic systolic heart failure in a presumed euvolemic state and on standard oral furosemide therapy (40 to 80 mg) were examined. At baseline, subjects were withdrawn from their loop diuretics. After 72 h, their furosemide regimen was reinstated, and patients were studied again 3 days later. Serum creatinine, atrial and B-type natriuretic peptide, urinary kidney injury molecule (KIM)-1, urinary N-acetyl-beta-D-glucosaminidase (NAG), and serum as well as urinary neutrophil gelatinase–associated lipocalin (NGAL) were determined at various time points. Results Diuretic withdrawal resulted in increases in atrial and B-type natriuretic peptide (both p < 0.05). Serum creatinine was unaffected. Both urinary KIM-1 (p < 0.001) and NAG (p = 0.010) concentrations rose significantly, after diuretic withdrawal, whereas serum and urinary NGAL were not significantly affected. After reinitiation of furosemide, both urinary KIM-1 and NAG concentrations returned to baseline (both p < 0.05), but NGAL values were unaffected. Conclusions Subclinical changes in volume status by diuretic withdrawal and reinstitution are associated with increases and decreases of markers of tubular dysfunction in stable heart failure. Diuretic therapy may favorably affect renal and tubular function by decreasing congestion