Spelling suggestions: "subject:" retrieval"" "subject:" etrieval""
1 |
Atmospheric ozone retrieval using radiance measurements from the Chappuis and Hartley-Huggins absorption bandsRoth, Christopher Z. 27 March 2007
The monitoring of global ozone in the atmosphere is a necessary prerequisite to understanding atmospheric chemistry and managing atmospheric constituents. Satellite systems have been developed to measure ozone and other constituents accurately on a global basis. However, within this area there is considerable room for advancement in the techniques used to measure ozone from a satellite platform.<p>The Canadian instrument OSIRIS onboard the Swedish-led satellite Odin contains an optical spectrograph that is used for measuring limb radiance in the atmosphere. There are various proven techniques to convert limb radiance data into ozone density profiles. This work presents a new technique that combines radiance data from both the Chappuis and Hartley-Huggins bands to retrieve ozone density. The new technique extends the current upper limit of Chappuis-only retrievals from 40 km to 60 km.<p>The major portion of this work describes the implementation of this new technique. Briefly, a Multiplicative Algebraic Reconstructive Technique, together with the SaskTRAN radiative transfer model, is used to invert the limb radiance data into ozone density profiles.<p>An overview of the resulting ozone density profiles is presented together with comparisons against other ozone products as a first order verification of the results.<p>This work will be used to produce a new ozone data set from the OSIRIS limb radiance data consisting of ozone density profiles that are valid to 60 km.
|
2 |
Atmospheric ozone retrieval using radiance measurements from the Chappuis and Hartley-Huggins absorption bandsRoth, Christopher Z. 27 March 2007 (has links)
The monitoring of global ozone in the atmosphere is a necessary prerequisite to understanding atmospheric chemistry and managing atmospheric constituents. Satellite systems have been developed to measure ozone and other constituents accurately on a global basis. However, within this area there is considerable room for advancement in the techniques used to measure ozone from a satellite platform.<p>The Canadian instrument OSIRIS onboard the Swedish-led satellite Odin contains an optical spectrograph that is used for measuring limb radiance in the atmosphere. There are various proven techniques to convert limb radiance data into ozone density profiles. This work presents a new technique that combines radiance data from both the Chappuis and Hartley-Huggins bands to retrieve ozone density. The new technique extends the current upper limit of Chappuis-only retrievals from 40 km to 60 km.<p>The major portion of this work describes the implementation of this new technique. Briefly, a Multiplicative Algebraic Reconstructive Technique, together with the SaskTRAN radiative transfer model, is used to invert the limb radiance data into ozone density profiles.<p>An overview of the resulting ozone density profiles is presented together with comparisons against other ozone products as a first order verification of the results.<p>This work will be used to produce a new ozone data set from the OSIRIS limb radiance data consisting of ozone density profiles that are valid to 60 km.
|
3 |
Information retrieval performance enhancement using the average standard estimator and the multi-criteria decision weighted set of performance measuresAhram, Tareq Z. January 2008 (has links)
Thesis (Ph.D.)--University of Central Florida, 2008. / Adviser: Pamela McCauley-Bush. Includes bibliographical references (p. 181-197).
|
4 |
Information Retrieval in PsychologyHjørland, Birger January 1988 (has links)
lnformation retrieval is an important but generally neglected part of the research method in psychology. On the basis of a case study, which consists of an examination of the search strategy in a Swedish dissertation, the problems of searching are overviewed,
with regard to both the selection of sources, and the construction of the secarch profile. Attention is givent to subject faceting in psychology.A model used by Psychological Abstracts in building on the
concepts of experimental variables is replaced by a facet model developed on the basis of the Bliss Classification System. This model is illustrated using the above-mentioned dissertation as an example, and it is shown that the model can help in formulating search queries in psycholory. Also discussed are problems that concern the
use of abstracts or full texts in the selection of documents. In addition, atteniion is given to the question of types of research in psychology that can or cannot benefit from computer-based retrievl methods.
|
5 |
Analysis of Multiple Query Reformulations on the Web: The Interactive Information Retrieval ContextRieh, Soo Young, Xie, Hong Iris January 2006 (has links)
This preprint has been published in Information Processing & Management 42 (2006): 751-768. This study examines multiple query reformulations on the Web in the context of interactive information retrieval. The results indicate that query reformulation is the product of user interaction with the IR system as well as the cognitive, affective, and situation levels from the user side.
|
6 |
Search Engine : An Effective tool for exploring the InternetW.M. Tharanga Dilruk, Ranasinghe January 2006 (has links)
The Internet has become the largest source of information. Today, millions of Websites exist and this number continuous to grow. Finding the right information at the right time is the challenge in the Internet age. Search engine is searchable database which allows locating the information on the Internet by submitting the keywords. Search engines can be divided into two categories as the Individual and Meta Search engines. This article discusses the features of these search engines in detail.
|
7 |
Signal and Noise: Social Construction and RepresentationTonkin, Emma January 2007 (has links)
This paper attempts to draw a quick sketch of some of the research that relates to the state of social tagging research today. The result is intended to be representative rather than exhaustive. The goal of indexing consistency is discussed and examined with respect to the specificities of differing indexing systems. The relation of indexing consistency with 'language-in-use' is discussed. We then proceed to take a look at a few examples of much older systems that relate closely with the lessons now being learned in social tagging today, in order to situate the present activity in its historical context â and examine a few approaches used for text-based search-and-retrieval and their relevance to tag corpora. To conclude, some distinctions between personal, social and global information management are discussed.
|
8 |
Image indexing using compressed colour histogramsBerens, Jeff January 2002 (has links)
No description available.
|
9 |
Search in personal spacesPenev, Alexander , Computer Science & Engineering, Faculty of Engineering, UNSW January 2009 (has links)
Technology surrounds us with many daily Search tasks. However, there is a fundamental difference---one of user familiarity and control---that differentiates between search tasks in impersonal and personal search spaces. The World Wide Web itself is largely unknown, unfamiliar and impersonal to a user. In contrast, users regularly search in more `personal' spaces, such as their own files, their web history, bookmarks, downloads, and so on. These spaces are personal because the user has more knowledge, familiarity and control over their content. A byproduct of these qualities is that search in personal spaces is typically navigational: to navigate through or to recover familiar information. This differs from web search, where very often a user is trying to discover new or unknown information. This important difference in search intent means that there are often few `correct' results for a query in personal spaces, which is something we must keep in mind when implementing search algorithms. This thesis leverages structure and metadata to build novel algorithms for improving search in several important personal search spaces: finding a file in a file hierarchy, website navigation on a mobile phone browser, tag-based search in an online bookmarking system, and sponsoring content on mobiles. The proposed methods are highly practical and applicable to current real-life search problems that affect millions of users.
|
10 |
Part of speech N-grams for information retrievalLioma, Christina Amalia. January 2008 (has links)
Thesis (Ph.D.) - University of Glasgow, 2008. / Ph.D. thesis submitted to the Department of Computing Science, Faculty of Information and Mathematical Sciences, University of Glasgow, 2008. Includes bibliographical references. Print version also available.
|
Page generated in 0.0429 seconds