A cycle-based evolutionary algorithm for the fixed-charge capacitated multi-commodity network design problem

This paper presents an evolutionary algorithm for the fixed-charge multicommodity network design problem (MCNDP), which concerns routing multiple commodities from origins to destinations by designing a network through selecting arcs, with an objective of minimizing the fixed costs of the selected arcs plus the variable costs of the flows on each arc. The proposed algorithm evolves a pool of solutions using principles of scatter search, interlinked with an iterated local search as an improvement method. New cycle-based neighborhood operators are presented which enable complete or partial re-routing of multiple commodities. An efficient perturbation strategy, inspired by ejection chains, is introduced to perform local compound cycle-based moves to explore different parts of the solution space. The algorithm also allows infeasible solutions violating arc capacities while performing the "ejection cycles", and subsequently restores feasibility by systematically applying correction moves. Computational experiments on benchmark MCNDP instances show that the proposed solution method consistently produces high-quality solutions in reasonable computational times

The congested multicommodity network design problem

This paper studies a version of the fixed-charge multicommodity network design problem where in addition to the traditional costs of flow and design, congestion at nodes is explicitly considered. The problem is initially modeled as a nonlinear integer programming formulation and two solution approaches are proposed: (i) a reformulation of the problem as a mixed integer second order cone program to optimally solve the problem for small to medium scale problem instances, and (ii) an evolutionary algorithm using elements of iterated local search and scatter search to provide upper bounds. Extensive computational results on new benchmark problem instances and on real case data are presented

Enabling the freight traffic controller for collaborative multi-drop urban logistics: practical and theoretical challenges

There is increasing interest in how horizontal collaboration between parcel carriers might help alleviate problems associated with last-mile logistics in congested urban centers. Through a detailed review of the literature on parcel logistics pertaining to collaboration, along with practical insights from carriers operating in the United Kingdom, this paper examines the challenges that will be faced in optimizing multicarrier, multidrop collection, and delivery schedules. A “freight traffic controller” (FTC) concept is proposed. The FTC would be a trusted third party, assigned to equitably manage the work allocation between collaborating carriers and the passage of vehicles over the last mile when joint benefits to the parties could be achieved. Creating this FTC concept required a combinatorial optimization approach for evaluation of the many combinations of hub locations, network configuration, and routing options for vehicle or walking to find the true value of each potential collaboration. At the same time, the traffic, social, and environmental impacts of these activities had to be considered. Cooperative game theory is a way to investigate the formation of collaborations (or coalitions), and the analysis used in this study identified a significant shortfall in current applications of this theory to last-mile parcel logistics. Application of theory to urban freight logistics has, thus far, failed to account for critical concerns including (a) the mismatch of vehicle parking locations relative to actual delivery addresses; (b) the combination of deliveries with collections, requests for the latter often being received in real time during the round; and (c) the variability in travel times and route options attributable to traffic and road network conditions

PPAR-alpha L162V polymorphism in human hepatocellular carcinoma

Background/aims: Several lines of evidence suggest that peroxisome proliferator-activated receptor alpha may be involved in hepatocarcinogenesis. L162V polymorphism of the peroxisome proliferator-activated receptor alpha gene enhances the transactivation activity of this transcription factor. The aim of this study was to determine the frequency and clinical correlates of peroxisome proliferator-activated receptor alpha L162V polymorphism in hepatitis virus-induced hepatocellular carcinoma. Methods: 90 hepatocellular carcinoma patients diagnosed at Ankara University Gastroenterology Clinic between January 2002 and July 2003 and 80 healthy controls with normal body mass index, blood chemistry and with negative viral serology were included. peroxisome proliferator-activated receptor alpha L162V polymorphism was determined by PCR-RFLP. Results: hepatocellular carcinoma etiologies were as follows: 56 HBV, 12 HBV+HDV, 22 HCV. Eighty-seven patients (97%) were cirrhotic, and 60 patients (67.5%) had advanced tumors. In 83 (92%) of 90 hepatocellular carcinoma patients, gene segment including polymorphic region could be amplified by PCR (50 HBV, 12 HBV+HDV, 21 HCV) and 6 of them (7.2%, all infected with HBV) had L162V polymorphism, while 2 (2.5%) of 80 controls had this polymorphism (p=0.162). This trend became more remarkable when only HBV (HBV+HDV)-infected patients were compared with controls (6/62, 9.7% vs. 2/80, 2.5%, respectively, p=0.071). Five of 6 patients with L162V had advanced disease. Conclusions: Peroxisome proliferator-activated receptor alpha L162V polymorphism tends to occur in HBV-induced epatocellular carcinoma and is absent in HCV-related epatocellular carcinoma. These findings may show clues for the existence of different carcinogenesis mechanisms in these two common etiologies. Frequent occurrence of advanced disease in patients with L162V polymorphism suggests a role for this polymorphism in tumor progression

The psychology of mountaineering: A systematic review

Research on the psychology of mountaineering has received widespread attention over many decades. Therefore, to clarify scientific findings in the area, provide future research directions, and enable the development of applied recommendations to enhance performance and safety, the purpose of this systematic mixed studies review was to identify, appraise, and synthesise research on the psychology of mountaineering. After systematically searching 10 electronic databases and undertaking manual searches up to April 2020, 69 studies published over 54 years (1966-2020) were included in the review. Thematic synthesis was undertaken and generated 11 descriptive themes, which were captured by two analytical themes, (i) personality characteristics of mountaineers, and (ii) psychological experiences in mountaineering. The synthesis generated novel insights into connections between different research topics in the psychology-specific literature in mountaineering, thus providing a more advanced understanding of current knowledge in this area. The review highlights that considerable progress has been made in this field, but further high-quality studies are required across all facets of this literature. Future avenues for research include: group dynamics; cognitive mechanisms underlying decision-making; and coping with setbacks and traumatic events

a review of methodological design choices

Publisher Copyright: © 2023 Cambridge University Press. All rights reserved.This systematic literature review aimed to provide an overview of the characteristics and methods used in studies applying the Disability-Adjusted Life Years (DALY) concept for infectious diseases within European Union (EU)/European Economic Area (EEA)/European Free Trade Association (EFTA) countries and the United Kingdom. Electronic databases and grey literature were searched for articles reporting the assessment of DALY and its components. We considered studies in which researchers performed DALY calculations using primary epidemiological data input sources. We screened 3,053 studies of which 2,948 were excluded and 105 studies met our inclusion criteria. Of these studies, 22 were multi-country and 83 were single-country studies, of which 46 were from the Netherlands. Food- and water-borne diseases were the most frequently studied infectious diseases. Between 2015 and 2022, the number of burden of infectious disease studies was 1.6 times higher compared to that published between 2000 and 2014. Almost all studies (97%) estimated DALYs based on the incidence- and pathogen-based approach and without social weighting functions; however, there was less methodological consensus with regards to the disability weights and life tables that were applied. The number of burden of infectious disease studies undertaken across Europe has increased over time. Development and use of guidelines will promote performing burden of infectious disease studies and facilitate comparability of the results.publishersversionepub_ahead_of_prin