1,720,952 research outputs found
Scenario tree airline fleet planning for demand uncertainty
No full textThis paper proposes an innovative multi-period modeling approach to solve the airline fleet planning problem under demand uncertainty. The problem is modeled using a scenario tree approach. The tree is composed of nodes, which represent points of decision in multiple time stages of the planning horizon, and branches, representing demand variation scenarios. The branches link the decision nodes in consequent time stages and compose scenario paths. Fleet decisions are modeled according to these scenario paths, resembling the real-life process in which fleet plans are not defined in a single moment but instead are adjusted according to the demand development. Given that some scenario paths share common decision nodes, decisions among scenarios need to be synchronized. A mixed-integer linear programming model is proposed to determine the ideal fleet composition for each scenario in the tree and to describe this interdependency between scenarios. Given the probability of a scenario, fleet composition probabilities for each time-period can be determined. Two real-world based case studies are performed to show the validity of the model. Results show that the proposed scenario tree approach can provide flexible multi-period airline fleet plans, which are more robust to future demand scenarios than fleet solutions obtained using the traditional approach of considering a single deterministic demand evolution scenario.Air Transport & Operation
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Heliport Gorinchem - Designing an Aerial Logistic Network
No full textThe Dutch city of Gorinchem has great economic growth opportunities for the future, but is limited by its transport system. It is strategically located at a crossroad of two motorways and two rivers, the Boven-Merwede and the Linge. Gorinchem is home to a number of multinationals, among others Damen Shipyards and Van Oord. This sets the right conditions for economic growth. However, the city roads are congested and the limited accessibility of the area by train and car slows this economic growth. Therefore, a solution is required to make Gorinchem more accessible. The development of an aerial network is an approach that could comply with the vision of the city as an innovative regional business centre. This project, called Heliport Gorinchem, aims to provide a final design for an aerial logistic network that can be implemented in Gorinchem in the year 2020. The project consists of three main parts: the project initiation and definition, a conceptual design part, and a detailed design part. This report contains a review of the project initiation and definition, and the conceptual design part. The main focus of this report is on the detailed design part of the project. The aim of the project initiation and definition is to structure the project, come up with a time management plan and organise the group. Also, the requirements and constraints for the project are set. The goal of the project is to design a concept for a sustainable logistic network of multi-purpose aerial vehicles in Gorinchem, competitive with the current transport market, within ten weeks. A market analysis is performed after the project initiation, to identify the traffic problem in Gorinchem on a local and regional scale. Locally, the city has three connection points to the motorways and these points form the entry and exit of the city. The capacity of the roads to these points is too low for the traffic they have to handle. It is estimated that there is an overload of 4000 travellers per hour during rush hours. On a regional level, a connection with a railway to the north and south of the country fails to appear and there is no aerodrome near Gorinchem to have any connection by air. The outcome of the conceptual design part is a concept for an operational aerial network. To come up with ideas for possible concepts for the network, multiple brainstorm sessions are held. A selection procedure is executed in order to reduce the amount of possible concepts and to come up with a final concept for the detailed design part of the project. From this, a combination of a linear local and a linear regional network is selected. The verification of the conceptual design has led to the conclusion that an aerial network alone will not solve the traffic problem entirely at this moment. However, there is a demand for a better accessibility and economic growth in of the city. Therefore the aim of the project is altered into a new vision. The goal of the aerial network is to serve economic growth of the city. An aerial network will allow Gorinchem to improve its accessibility to important locations, while becoming an important link in the aerial infrastructure of the Netherlands. The aim is therefore to implement an aerial network before 2020. In the short term, up to 2030, the goal is to realise a profitable aerial network. In the years thereafter an expansion of the aerial network will allow for an improvement of the traffic situation in Gorinchem. This is the aim of the long-term vision. The detailed design part elaborates on the design of all aspects of the aerial network in the short term, while keeping its long-term development in mind. The main customers are identified to be business travellers. Other smaller markets are determined as well, like tourism, medical assistance and governmental flights. The aerial vehicle for the short term is selected to be an Eurocopter EC135 helicopter that makes use of a hybrid engine and noise reducing technology. The helicopter should operate under visual flight rules to limit the investment costs. The aerodrome is designed to be a self-sustaining heliport with a low investment cost of 750,000 euro for the landing site. For the location, the industrial estate Avelingen at the edge of the suburbs is chosen. It has a direct connection with the motorway and can be linked with the future railway from Breda to Utrecht. Furthermore, it is located at the Boven-Merwede river which has an extra advantage. An approach route for helicopters will minimise the environmental impact regarding noise and safety. A business model for the aerial network has been developed and analysed. Unfortunately, the business model shows that it will not be profitable in the short term to set up a transport service for business travellers. The main reasons for this are the high maintenance costs of the vehicle, call out costs, and airport charges. From the conducted research, it can be concluded that it is possible to realise a heliport in Gorinchem and start its operations in the year 2020. Although the implementation of a profitable aerial network seems currently not feasible, it is reasonable to invest in the construction of a heliport as there is demand for a heliport in Gorinchem. It is advised to develop a heliport that allows companies like Damen Shipyards and Van Oord to use the facilities with their own helicopter. Furthermore, this will be a first and innovative step in the development of a regional aerial network, which provides fast and high quality transport. This can offer Gorinchem the opportunity to take a leading role in aerial transportation on a regional scale in the Netherlands . Furthermore, it will support the economic growth of the city. Further research should focus on the design of a new aerial vehicle. It is recommended that maintenance and fuel cost are reduced for the new aerial vehicle in order to make the aerial network profitable. Other research should focus on the expansion of the aerial network and find alternative locations with low landing charges. In this way, the high landing fees at the airports can be avoided and the possibility to make a profitable aerial network will increase. It is recommended to perform a market analysis on the willingness to pay of the future business travellers and other markets. This will have influence on the income of the business model. In the best case scenario, the design can even become profitable in the short term.Air Transport and OperationsAerospace Engineerin
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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