305,180 research outputs found
STRATEGIES TO EVALUATE THE VISIBILITY ALONG AN INDOOR PATH IN A POINT CLOUD REPRESENTATION
No full textMany research works have been oriented to the formulation of different algorithms for estimating the paths in indoor environments from three-dimensional representations of space. The architectural configuration, the actions that take place within it, and the location of some objects in the space influence the paths along which is it possible to move, as they may cause visibility problems. To overcome the visibility issue, different methods have been proposed which allow to identify the visible areas and from a certain point of view, but often they do not take into account the user's visual perception of the environment and not allow estimating how much may be complicated to follow a certain path. In the field of space syntax and cognitive science, it has been attempted to describe the characteristics of a building or an urban environment by the isovists and visibility graphs methods; some numerical properties of these representations allow to describe the space as for how it is perceived by a user. However, most of these studies are directed to analyze the environment in a two-dimensional space. In this paper we propose a method to evaluate in a quantitative way the complexity of a certain path within an environment represented by a three-dimensional point cloud, by the combination of some of the previously mentioned techniques, considering the space visible from a certain point of view, depending on the moving agent (pedestrian , people in wheelchairs, UAV, UGV, robot)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Driedimensionale Topografische Terreinmodellering op basis van Tetraëder Netwerken: Top10-3D
No full textDelauney tetrahedralizations: Honor degenerated cases
No full textThe definition of a Delaunay tetrahedralization (DT) of a set S of points is well known: a DT is a tetrahedralization of S in which every simplex (tetrahedron, triangle, or edge) is Delaunay. A simplex is Delaunay if all of its vertices can be connected by a circumsphere that encloses no other vertex. An important remark made in virtually all papers on this topic is that “although any number of vertices is permitted on the sphere”, a Delaunay tetrahedralization is unique “only if the points are in general position, which is the absence of degeneracy (i.e., five or more vertices possible on the circumsphere)”. For applications in which the DT must be unique and invariant invariable under either geometrical rotation or the numbering of the points of set S, degenerated cases are expected to be resolved or at least indicated. This research, however, will direct to a method in which degenerated cases are not solved by a geometrically distorted set of input data using Steiner Points, nor is just one of the possible ‘unique’ DTs generated. To the contrary, an extra type of ‘non-geometrical’, flat, zero-volume ‘tetrahedra’ is purposely introduced in order to indicate the degenerated cases within the applied data structure of the tetrahedralization. The four vertices of these flat tetrahedra lie on the same circumsphere as the vertices of their neighboring tetrahedra. Once the set S of points is tetrahedralized, these flat tetrahedra provide a tool with which to discover other ‘unique’ DTs of the set S of points. From this set of unique DTs, the one having a global optimum can be selected for a given purpose, e.g. to support datadependent applications. Another benefit in creating flat tetrahedra is the ability to indicate nearly degenerated cases, eliminating the need for exact arithmetic.OTB onderzoekOTB Research Institute for the Built Environmen
Vernieuwde master 'Geomatics for the built environment
No full textOTB ResearchOTB Research Institute for the Built Environmen
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
No full textThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
Indoor Signposting and Wayfinding through an Adaptation of the Dutch Cyclist Junction Network System
No full textFinding one's way in complex indoor settings can be a quite stressful and time-consuming task, especially for users unfamiliar with the environment. There have been several different approaches to provide wayfinding assistance in order to guide a person from a starting point to a destination, ranging from traditional maps and signposting systems to the most recent developments of navigation systems displaying direction information on a mobile device screen. However, so far none of them has emerged to be efficient enough in order to act as a uniform solution for the wayfinding problem in indoor environments. Moreover, referencing to landmarks is not widely employed by wayfinding assistance systems despite the fact that landmark-based navigation is the most common way for people to navigate themselves through unfamiliar environments. The aim of this work is to propose a new wayfinding assistance method for indoor environments that makes use of the landmark concept. The method to achieve it is by translating the main principles of an already existing outdoor system named Junction Network System, which applies successfully for providing guidance to cyclists in The Netherlands. The most important parameter of the system is that assistance is provided to users where they actually need to make a directional choice. The first step is to automatically define the locations, i.e. the decision points, where wayfinding assistance is needed in indoor settings and the second is to supply them with a special type of landmark which will have the form of a signpost that provides all the necessary information. A graph based representation of the indoor setting is generated in order to extract the decision points and create the network of all possible routes in the environment. The conceptual framework for the determination of the decision points is implemented in two case studies: GeoFort main building and the Faculty of Architecture and the Built Environment (BK) of TU Delft. Two different building cases are used in order to gain an insight on how the system can be applied in different indoor environments. The part of the navigable indoor space where movement mainly occurs when people are in search of a destination was subdivided according to a geometric criterion (Constrained Delaunay Triangulation) while also the semantics of the space were taken into account in order to determine the decision points. By connecting all the decision points and the destinations a network of all the possible routes is created. A route is followed by referring to the sequence of numbers corresponding to the nodes of the network. The proposed system was verified based on a human-based survey. The proposed landmark-signs were installed at part of the faculty of Architecture and users were asked to find their way in the building relying only on them. The time to reach the destination and the number of detours were counted, while a questionnaire-based survey was used in order to further investigate the feelings and views of participants regarding the effectiveness of the system. The findings of the experiment are quite promising, as the performance of the participants in both measures was very good. Additionally, the results of the questionnaire indicate that users consider the system simple and comprehensive and they are in general satisfied by the provided assistance. However, further implementation and testing in more indoor space cases is needed in order to draw an indisputable conclusion about its effectiveness. Nevertheless, an important contribution of the research is the generation of a conceptual model in order to automatically determine the decision points in indoor environments that this can be applied invariable to other wayfinding assistance systems.GeomaticsGeomaticsArchitecture and The Built Environmen
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