scholarly journals The Surgical Patient Routing Problem: A Central Planner Approach

2016 ◽  
Vol 28 (4) ◽  
pp. 657-673 ◽  
Author(s):  
Sepehr Nemati ◽  
Oleg V. Shylo ◽  
Oleg A. Prokopyev ◽  
Andrew J. Schaefer
Keyword(s):  
Surgical Patient ◽  
Routing Problem ◽  
Central Planner

Fuzzy multi-objective location and routing problem

2020 ◽  
Vol 39 (3) ◽  
pp. 3259-3273
Author(s):  
Nasser Shahsavari-Pour ◽  
Najmeh Bahram-Pour ◽  
Mojde Kazemi
Keyword(s):  
Firefly Algorithm ◽  
High Reliability ◽  
Research Area ◽  
Nsga Ii ◽  
Location Routing Problem ◽  
Routing Problem ◽  
Location Allocation ◽  
Multi Objective ◽  
Location Routing ◽  
The Cost

The location-routing problem is a research area that simultaneously solves location-allocation and vehicle routing issues. It is critical to delivering emergency goods to customers with high reliability. In this paper, reliability in location and routing problems was considered as the probability of failure in depots, vehicles, and routs. The problem has two objectives, minimizing the cost and maximizing the reliability, the latter expressed by minimizing the expected cost of failure. First, a mathematical model of the problem was presented and due to its NP-hard nature, it was solved by a meta-heuristic approach using a NSGA-II algorithm and a discrete multi-objective firefly algorithm. The efficiency of these algorithms was studied through a complete set of examples and it was found that the multi-objective discrete firefly algorithm has a better Diversification Metric (DM) index; the Mean Ideal Distance (MID) and Spacing Metric (SM) indexes are only suitable for small to medium problems, losing their effectiveness for big problems.

Evaluation and treatment of children with radiation-induced cerebral vasculopathy

2019 ◽  
Vol 24 (6) ◽  
pp. 680-688
Author(s):  
David S. Hersh ◽  
Kenneth Moore ◽  
Vincent Nguyen ◽  
Lucas Elijovich ◽  
Asim F. Choudhri ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Proton Beam ◽  
Tumor Imaging ◽  
Clinic Visit ◽  
Surgical Patient ◽  
Beam Radiation ◽  
Proton Beam Radiotherapy ◽  
Cranial Radiation ◽  
Delayed Complication ◽  
Radiation Induced

OBJECTIVEStenoocclusive cerebral vasculopathy is an infrequent delayed complication of ionizing radiation. It has been well described with photon-based radiation therapy but less so following proton-beam radiotherapy. The authors report their recent institutional experience in evaluating and treating children with radiation-induced cerebral vasculopathy.METHODSEligible patients were age 21 years or younger who had a history of cranial radiation and subsequently developed vascular narrowing detected by MR arteriography that was significant enough to warrant cerebral angiography, with or without ischemic symptoms. The study period was January 2011 to March 2019.RESULTSThirty-one patients met the study inclusion criteria. Their median age was 12 years, and 18 (58%) were male. Proton-beam radiation therapy was used in 20 patients (64.5%) and photon-based radiation therapy was used in 11 patients (35.5%). Patients were most commonly referred for workup as a result of incidental findings on surveillance tumor imaging (n = 23; 74.2%). Proton-beam patients had a shorter median time from radiotherapy to catheter angiography (24.1 months [IQR 16.8–35.4 months]) than patients who underwent photon-based radiation therapy (48.2 months [IQR 26.6–61.1 months]; p = 0.04). Eighteen hemispheres were revascularized in 15 patients. One surgical patient suffered a contralateral hemispheric infarct 2 weeks after revascularization; no child treated medically (aspirin) has had a stroke to date. The median follow-up duration was 29.2 months (IQR 21.8–54.0 months) from the date of the first catheter angiogram to last clinic visit.CONCLUSIONSAll children who receive cranial radiation therapy from any source, particularly if the parasellar region was involved and the child was young at the time of treatment, require close surveillance for the development of vasculopathy. A structured and detailed evaluation is necessary to determine optimal treatment.

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