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

Solving school bus routing problems through integer programming

In this paper, an exact solution approach is described for solving a real-life school bus routing problem (SBRP) for transporting the students of an elementary school throughout central Ankara, Turkey. The problem is modelled as a capacitated and distance constrained open vehicle routing problem and an associated integer linear program is presented. The integer program borrows some well-known inequalities from the vehicle routing problem, which are also shown to be valid for the SBRP under consideration. The optimal solution of the problem is computed using the proposed formulation, resulting in a saving of up to 28.6 in total travelling cost as compared to the current implementation. © 2007 Operational Research Society Ltd. All rights reserved

Child tracking system using smartphone

The number of missing children and kidnapping is on the rise in recent years. Every parent wills definitely going through an agonizing experience to have their children missing. Therefore, there are many safety measurements to prevent this incident from happening. The help of modern technologies is one of the ways to reduce children missing and kidnapping. A child can be tracked by using the global positioning system (GPS) and global system for mobile communication (GSM) technology. Advanced child monitoring systems are expensive. Not all families have the same living standards. For this purpose, a low-cost child tracking system is proposed in this study. The implementation of the proposed approach is reported in real-time

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

State stigmatization in urban Turkey : Managing the 'insurgent' squatter dwellers in Dikmen Valley

This paper contributes to the accounts of territorial stigmatisation by examining the state role in it in the case of Turkey, a country that suffers from growing state power. The existing debates are mainly restricted to its function as an economic strategy paving the way for capital accumulation through devaluing working‐class people and places. Drawing on textual analysis of political speeches, local newsletters and mainstream national newspapers and fieldwork material that include interviews and observations in Dikmen Valley where some squatter communities mobilised against the state‐imposed urban transformation project, I demonstrate that state conceptualisation of “problem people” targets the “insurgent” rather than the “unprofitable” groups. Stigma in urban settings functions in inciting the desire to meet the patterns deemed appropriate by the state, rather than the market. Moving from that, I argue that stigma is used as a state‐led political strategy, which is integral to the growing authoritarianism in Turkey

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

GeoGCD: improved visual search via gaze-contingent display

Gaze-Contingent Displays (GCDs) can improve visual search performance on large displays. GCDs, a Level Of Detail (LOD) management technique, discards redundant peripheral detail using various human visual perception models. Models of depth and contrast perception (e.g., depth-of-field and foveation) have often been studied to address the trade-off between the computational and perceptual benefits of GCDs. However, color perception models and combinations of multiple models have not received as much attention. In this paper, we present GeoGCD which uses individual contrast, color, and depth-perception models, and their combination to render scenes without perceptible latency. As proof-of-concept, we present a three-stage user evaluation built upon geographic image interpretation tasks. GeoGCD does not impair users’ visual search performance or affect their display preferences. On the contrary, in some cases, it can significantly improve users’ performance