Search results for "RAM"
showing 10 items of 35643 documents
Development of sense of coherence during two group interventions
2012
Burnout is a serious occupational hazard. This study investigated the possibility to develop an effective salutogenic group intervention among employees suffering from severe burnout symptoms. Participants consisted of employees aged 31 to 59 years working in different public service occupations, such as police officers, tax officers, (and other public service officers), and assigned to three different groups: analytic (N = 25), psychodramatic (N = 24) and controls (N = 28). The intervention comprised 16 separate days over a nine-month period. Changes in sense of coherence (SOC) were measured four times with the 13-item Orientation to Life Questionnaire during the intervention and at six-mo…
Charitable food aid in Finland: from a social issue to an environmental solution
2019
Since the establishment of the first food bank in 1995, charitable food aid (CFA) has become entrenched in Finland as a seemingly irreplaceable solution to food poverty. Further, it has recently been suggested that the focus of food aid activities is shifting from food poverty and temporary hunger alleviation towards environmental sustainability through addressing food waste via organized re-distribution of expiring food from retail to charitable organizations. This potentially creates a mechanism that (1) solidifies food poverty and (2) fortifies the paradoxical situation where charitable organizations delivering food aid are dependent on food waste rather than trying to reduce it. To unde…
Automated Valuation Methods in Atypical Real Estate Markets Using the Mono-parametric Approach
2017
The appraisal objectivity depends on the possibility to quickly and easily access to reliable real estate data in order to apply appropriate appraisal approaches. In order to ensure the objectivity of the real estate appraisals, in recent years Automated Valuation Methods (AVM) have been developed, integrating computerized real estate databases and programming languages. The Automated Valuation Methods proposed at international level usually recur to regression models, aimed to return appraisal equations based on reliable real estate databases. This approach is not applicable in some markets where lack of data does not allow the implementation of regression models. This paper proposes to im…
Variable Fixing for Two-Arc Sequences in Branch-Price-and-Cut Algorithms on Path-Based Models
2020
Variable fixing by reduced costs is a popular technique for accelerating the solution process of mixed-integer linear programs. For vehicle-routing problems solved by branch-price-and-cut algorithms, it is possible to fix to zero the variables associated with all routes containing at least one arc from a subset of arcs determined according to the dual solution of a linear relaxation. This is equivalent to removing these arcs from the network used to generate the routes. In this paper, we extend this technique to routes containing sequences of two arcs. Such sequences or their arcs cannot be removed directly from the network because routes traversing only one arc of a sequence might still b…
‘Tool port’ to ‘landlord port’: a game theory approach to analyse gains from governance model transformation
2018
This study investigates potential port users’ surplus and terminal operators’ profits due to transforming port governance from the ‘tool port’ model to the ‘landlord port’ model. Although the landl...
Relative Reachability Analysis as a Tool for Urban Mobility Planning
2019
There is a plethora of user-oriented route planning applications and systems that enable the computation of the fastest journey between two locations using different transportation modes, e.g., car, public transport, walking, bicycle. While useful for individuals, they are of limited interest to a class of users that may be interested in a more global and comparative view of transportation systems in general. In this context, we adopt the view of an urban planner. Urban planners may be interested in queries such as "if a new transit stop was to be introduced in a given location, would that bring the travel time to a given point-of-interest (POI) or area-of-interest (AOI) by bus closer to th…
Novel Distance Estimation Methods Using 'Stochastic Learning on the Line' Strategies
2018
In this paper, we consider the problem of Distance Estimation (DE) when the inputs are the $x$ and $y$ coordinates (or equivalently, the latitudinal and longitudinal positions) of the points under consideration. The aim of the problem is to yield an accurate value for the real (road) distance between the points specified by the latter coordinates. 1 This problem has, typically, been tackled by utilizing parametric functions called the “Distance Estimation Functions” (DEFs). The parameters are learned from the training data (i.e., the true road distances) between a subset of the points under consideration. We propose to use Learning Automata (LA)-based strategies to solve the problem. In par…
A more efficient cutting planes approach for the green vehicle routing problem with capacitated alternative fuel stations
2021
AbstractThe Green Vehicle Routing Problem with Capacitated Alternative Fuel Stations assumes that, at each station, the number of vehicles simultaneously refueling cannot exceed the number of available pumps. The state-of-the-art solution method, based on the generation of all feasible non-dominated paths, performs well only with up to 2 pumps. In fact, it needs cloning the paths between every pair of pumps. To overcome this issue, in this paper, we propose new path-based MILP models without cloning paths, for both the scenario with private stations (i.e., owned by the fleet manager) and that with public stations. Then, a more efficient cutting plane approach is designed for addressing both…
Exact solution of the soft-clustered vehicle-routing problem
2020
Abstract The soft-clustered vehicle-routing problem (SoftCluVRP) extends the classical capacitated vehicle-routing problem by one additional constraint: The customers are partitioned into clusters and feasible routes must respect the soft-cluster constraint, that is, all customers of the same cluster must be served by the same vehicle. In this article, we design and analyze different branch-and-price algorithms for the exact solution of the SoftCluVRP. The algorithms differ in the way the column-generation subproblem, a variant of the shortest-path problem with resource constraints (SPPRC), is solved. The standard approach for SPPRCs is based on dynamic-programming labeling algorithms. We s…
New exact methods for the time-invariant berth allocation and quay crane assignment problem
2019
Abstract Efficient management of operations in seaport container terminals has become a critical issue, due to the increase in maritime traffic and the strong competition between ports. In this paper we focus on two seaside operational problems: the Berth Allocation Problem and the Quay Crane Assignment Problem, which are considered in an integrated way. For the continuous BACAP problem with time-invariant crane assignment we propose a new mixed integer linear model in which the vessels can be moored at any position on the quay, not requiring any quay discretization. The model is enhanced by adding several families of valid inequalities. The resulting model is able to solve instances with u…