No abstract

ABSTRACT:As an important factor of VGI quality, this paper focuses on uncertainty arisen in assigning tags to features by VGI users. The VGI portals ask their users to assign (or tag) one or more data types to features, from a set of pre-defined types, whose meanings may be vague for the user, or distinctions between some of them are not clear, i.e. depend on the users' semantics. This research believes such uncertainties are the results of perceptual issues arising in serial communication between the system and the user. We categorize the problem, and then utilize semantic modelling to reduce such uncertainties. A hierarchy of feature types is produced. At each step, users are asked a simple question with clear distinct answers, which gradually directs the user to the right type. We will describe the approach and present the initial results for the hierarchy produced for major linear features of OpenStreetMap.

Diversity of practices and methods in all fields is the basis of emerging standards in different areas. World WideWeb Consortium (W3C) has standardized eXtensible Markup Language (XML) as a very convenient tool to structure data for numerous purposes. OGC standardized Geography Markup Language (GML), which is an XML-based language, to store and transport geospatial data. Despite the fact that it is a medium to separate georeferenced data from presentation, GML by itself is not intended to visualize geo-referenced data. One of the solutions to visualize GML is to use eXtensible Style sheet Language Transformation (XSLT) as transformer to a visualization language such as Scalable Vector Graphic (SVG). Unlike the usual procedure, the major advantage of the proposed approach is that the transformation process is shifted to the client-side. XSLT as a median language is a general-purpose transformation tool. As it is not specialized for map cartography, map making process is very complicated using this primitive language. To facilitate transformation process, in this research, XSLT is extended to meet cartography requirements. Furthermore, a graphical user interface (XCartoT) is designed to set all the map properties interactively. XCartoT provides a user-friendly interface for cartographers to automatically generate necessary XSL files for their intended maps. The goal of this research is to develop a major step towards the geospatial Web.

ABSTRACT:Knowing the position has been an ambition in many areas such as science, military, business, etc. GPS was the realization of this wish in 1970s. Technological advances such as ubiquitous computing, as a conquering perspective, requires any service to work for any user, any place, anytime, and via any network. As GPS cannot provide services in indoor environments, many scientists began to develop indoor positioning systems (IPS). Smart phones penetrating our everyday lives were a great platform to host IPS applications. Sensors in smart phones were another big motive to develop IPS applications. Many researchers have been working on the topic developing various applications. However, the applications introduced lack simplicity. In other words, they need to install a step counter or smart phone on the ankle, which makes it awkward and inapplicable in many situations. In the current study, a new IPS methodology is introduced using only the usual embedded sensors in the smart phones. The robustness of this methodology cannot compete with those of the aforementioned approaches. The price paid for simplicity was decreasing robustness and complicating the methods and formulations. However, methods or tricks to harness the errors to an acceptable range are introduced as the future works.