Search results for "Architecture"
showing 10 items of 3706 documents
Branch-and-Cut for the Split Delivery Vehicle Routing Problem with Time Windows
2019
The split delivery vehicle routing problem with time windows (SDVRPTW) is a notoriously hard combinatorial optimization problem. First, it is hard to find a useful compact mixed-integer programming (MIP) formulation for the SDVRPTW. Standard modeling approaches either suffer from inherent symmetries (mixed-integer programs with a vehicle index) or cannot exactly capture all aspects of feasibility. Because of the possibility to visit customers more than once, the standard mechanisms to propagate load and time along the routes fail. Second, the lack of useful formulations has rendered any direct MIP-based approach impossible. Up to now, the most effective exact algorithms for the SDVRPTW hav…
Branch-and-price-and-cut for a service network design and hub location problem
2015
In the context of combined road-rail freight transport, we study the integrated tactical planning of hub locations and the design of a frequency service network. We consider a number of real-world constraints such as multiple transshipments of requests at hubs, transport time limits for requests, request splitting, and outsourcing possibilities. To our knowledge, the combination of problem features we deal with has not been described before. We present a path-based model and solve it with a branch-and-price-and-cut algorithm. Computational experiments show that large realistic instances from a major German rail freight company can be solved close to optimality within one hour on a standard …
A GIS-Based Methodology to Estimate the Potential Demand of an Integrated Transport System
2017
In the design of a new public transport system or of an extension of an existing system, the choice of a suitable placement of stations and stops in the territory and the definition of the main axes are very important. The different choice in the number and distribution of the stops of a road transport system or of a railway transport system, in fact, makes the system more or less widespread and affects the consistency of the catchment area and the attractiveness of the system. The accessibility of a system, add to the reliability in providing the service, is the fundamental parameter influencing the modal split of the users. Therefore, the Public Administration must have tools able to eval…
The directed profitable rural postman problem with incompatibility constraints
2017
[EN] In this paper, we study a variant of the directed rural postman problem (RPP) where profits are asso- ciated with arcs to be served, and incompatibility constraints may exist between nodes and profitable arcs leaving them. If convenient, some of the incompatibilities can be removed provided that penalties are paid. The problem looks for a tour starting and ending at the depot that maximizes the difference between collected profits and total cost as sum of traveling costs and paid penalties, while satisfying remaining incompatibilities. The problem finds application in the domain of road transportation service, and in particular in the context of horizontal collaboration among carriers …
The periodic rural postman problem with irregular services on mixed graphs
2019
Abstract In this paper, we deal with an extension of the rural postman problem in which some links of a mixed graph must be traversed a given number of times over a time horizon. These links represent entities that must be serviced a specified number of times in some subsets of days (or periods) of the time horizon. The aim is to design a set of minimum-cost tours, one for each day/period of the time horizon, that satisfy the service requirements. We refer to this problem as the periodic rural postman problem with irregular services (PRPP–IS). Some practical applications of the problem can be found in road maintenance operations and road network surveillance, for example. In order to solve …
MOF-VM: Instantiation Revisited
2016
The Model-Driven Architecture (MDA) is based on an understanding of a hierarchy of levels that are placed on top of each other and that are connected with instantiation. For practical MDA use, it is important to be clear about the kinds of objects that reside on the different levels and the relations between them as well as relations to objects outside of the MDA domain. This article aims at enhancing the understanding of these objects and relations by relating them to a virtual MOF machine.
Word derivational knowledge and writing proficiency: How do they link?
2016
Abstract Although word derivational (WD) knowledge, i.e., how new words are formed from existing words with help of derivational affixes, is considered important for learners of second or foreign languages (L2), there is still no clear answer as to what aspects comprise the construct of L2 English word derivational knowledge and how it develops. The present study adds to our knowledge on how the ability to derive English words develops among L2 English learners. More specifically, it sheds light on how word derivational knowledge relates to communicatively defined Common European Framework of Reference (CEFR) language proficiency levels regarding learners' writing skills. In the study, 117 …
Software as ideology
2016
Software has become ubiquitous in higher education, especially often taken-for-granted Microsoft Word. Educational writing involves more than horizontal lines of text, but also multimodal representations. When students write in Word, the affordances of the program constrain what multimodal representations of knowledge they can and cannot make. Software such as Word is not neutral tool-kits, but also historical and semiotic constructs loaded with social values and ideologies. By taking a social semiotic approach to Word and SmartArt, this article shows how this software is pre-loaded with values and styles from office management. These values are then infused into education, in the case this…
The internally layered foot in Dutch
2017
AbstractRecent metrical studies have proposed that, under certain circumstances, a weak syllable may be adjoined to a binary foot, giving rise to a minimally recursive foot. Adding to a growing body of research from metrical stress and foot-conditioned phenomena in various languages, the goals of this paper are twofold. First, we aim at providing empirical evidence for internally layered feet based on the distribution of three foot-conditioned processes of Dutch: vowel reduction, glottal stop /ʔ/ insertion and /h/ licensing/deletion. Second, we explore a less studied theoretical and descriptive advantage of internally layered feet: their potential to predict phonological strength distinctio…
Does the source matter?
2018
Abstract This article provides an insight into the expression of reportative evidentiality in Spanish scientific articles published between 1799 and 1920. Central to the discussion is the presence and specificity of sources in reportative constructions. While contemporary scientific discourse prioritizes the use of specific, reportative-quotative evidentials, this is not a constant feature of articles analyzed in this study. In order to trace this historical variation, we established a classification of reportative constructions according to the specificity of the evidence they convey and we conducted both qualitative and quantitative analyses. According to our results, different specificit…