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The rapid development experienced by the transportation industry in the past decades has led to many configurations of networks and therefore to an explosion of variants in transportation problems, motivating researchers to look at broader logistic problems, beyond the basic vehicle routing problems. This work introduces a new type of problem scenario combining various attributes: a pickup and delivery problem with multiple regions, multiple depots, and multiple transportation modes. We provide definitions, a literature review, and a step‐by‐step construction of the mathematical models from a simple and well‐known scenario to the multiregion multidepot pickup and delivery problem (MR‐MDPDP). For each step the relevant literature is examined. Furthermore, we suggest possible extensions for prospective research.

This paper reports on the results of the VeRoLog Solver Challenge 2016-2017: the third solver challenge facilitated by VeRoLog, the EURO Working Group on Vehicle Routing and Logistics Optimization. The authors are the winners of second and third places, combined with members of the challenge organizing committee. The problem central to the challenge was a rich VRP: expensive and therefore scarce equipment was to be redistributed over customer locations within time windows. The difficulty was in creating combinations of pickups and deliveries that reduce the amount of equipment needed to execute the schedule, as well as the lengths of the routes and the number of vehicles used. This paper gives a description of the solution methods of the above-mentioned participants. The second place method involves sequences of 22 low level heuristics: each of these heuristics is associated with a transition probability to move to another low level heuristic. A randomly drawn sequence of these heuristics is applied to an initial solution, after which the probabilities are updated depending on whether

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Abstract:The Lower Siret Meadow forest habitats have been altered from natural structure because of commercial forestry operations, activities that are defining the forest management from previous decades. Afforestation programs aimed to test the introduction of exotic tree species in order to increase wood production and to reduce harvest time intervals. These commercial influences reflect in the decrease of natural forest areas, aspect that could influence the birds presence. Studies on the ecological impact of plantations on birds are scarce, and no studies were found regarding this aspect in the region. Using six different sample areas both in native and non-native tree plantations, we investigated how bird presence is influenced by the support capacity offered by both natural or non-native plantations and which vegetation variables are related to our results. We compared the data from the surveyed areas to relate birds presence and dependence on certain characteristics of the habitats. Our results pointed out that species diversity is higher in natural forests with local tree species and vegetation characteristics like forest canopy density, shrub coverage, and herbaceous layer.

Usually, in footwear technology the upper materials are backed with heat bonding textile materials in order to increase the tensile and tear strength and the thermal resistance of the entire structure due to higher thickness. The paper studies the effects of the backing with heat bonding textiles on air permeability, an important comfort characteristic. The influence of the heat bonding with lining on the air permeability was studied using 5 types of bovine leather for upper materials and 4 types of knitted and woven fabrics for lining. The method to determine the air permeability is relatively simple and known. The air flow passing through the sample fixed on the device with the face upward is measured for certain values for the pressure difference. The conclusion drawn from the experiment is somewhat surprising: the air permeability increases with the thickness. This contradicts the general behaviour of textile structures, for which the air permeability decreases with thickness.