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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Event modelling, detection and mining in multimedia surveillance videos

Anwar, Fahad January 2010 (has links)
Due to the advances in digital information technologies and dramatic drop in the prices of storage devices, the installation of visual surveillance systems (VSS) has become relatively inexpensive. However, maintaining the staff to monitor these CCTV sources is still a costly affair. Moreover, as the end users are becoming more aware of the vision based technologies, there is ever growing demand for advanced surveillance systems which can not only model and detect complex interesting events but can also provide intelligence to improve their operational management process. In this thesis we investigated the three main aspects of visual surveillance systems (event modelling, event detection and event mining) and propose the framework in which these different aspects of surveillance systems complement each other. The research contributions presented in the thesis mostly fall under the event mining and event modelling aspects of visual surveillance systems. Most of the previous work for mining multimedia events is based upon discovering/detecting already known abnormal events or deals with finding frequent event patterns. In contrast, in this thesis we present a framework to discover unknown anomalous events associated with a frequent sequence of events (AEASP); that is to discover events which are unlikely to follow a frequent sequence of events. This information can be very useful for discovering unknown abnormal events and can provide early actionable intelligence to redeploy resources to specific areas of view (such as PTZ camera or attention of a CCTV user). Discovery of anomalous events against a sequential pattern can also provide business intelligence for store management in the retail sector. The proposed event mining framework also takes the temporal aspect of AEASP into consideration, that is to discover anomalous events which are true for a specific time interval only and might not be an AEASP over a whole time spectrum and vice versa. To confront the process/memory expensive process of searching all the instances of multiple sequential patterns in each data sequence a dynamic sequential pattern search mechanism (DSPS_SM) is also introduced. Different experiments are conducted to evaluate the proposed AEASP mining algorithm's accuracy and performance. Next, we proposed an event mining framework to automate the process of generating appearance models of real world entities by utilising the results of already detected events and text streams of multimedia events. A comprehensive problem definition and entity appearance model generation framework is presented. To validate the proposed entity appearance model generation concept, we implemented the proposed algorithm and conducted the experiments by using "Columbia University Image Library (COIL-I 00)" object database [I). To address the event modelling aspect of surveillance systems we extended and modified the event description framework (EDF) presented in [2] and proposed the extended version of it (EDFE). EDFE not only increased EDF's capability to model complex multimedia events but also facilitated the event detection and event mining processes. Modelled events (generated by EDFE) and the event detection process is evaluated using sequences generated in laboratory and also from realistic surveillance environment, the results of experiments are then analysed using precision and recall measures.
42

Models of spatially-localised facial dynamics for robust expression recognition

Bourel, Fabrice January 2002 (has links)
No description available.
43

Object-based content representation and analysis for image retrieval

Turcat, Jean-Philippe January 2002 (has links)
No description available.
44

The contestation of code : a political economy of free software and open source

Berry, David M. January 2007 (has links)
No description available.
45

Comuco : a completely mobile language

Ngan, Chi Wang Leo January 2001 (has links)
No description available.
46

Adaptive compression algorithm for full colour three dimensional integral images

Zaharia, Ramona January 2001 (has links)
No description available.
47

Modelling bipedal locomotion using wavelets for figure animation

Sun, Wei January 2000 (has links)
No description available.
48

Memory mapping for a portable operating system

Aylward, A. R. January 1981 (has links)
No description available.
49

Rotation invariant classification of 3D surface texture using photometric stereo

Wu, Jiahua January 2003 (has links)
No description available.
50

An electronic market-making algorithm

Nuti, Giuseppe January 2008 (has links)
In finance, a market-maker quotes both a buy and a sell price in a financial instrument or commodity, with the intention of making a profit on the bid/ask spread. The function of market-making in financial instruments is at present almost exclusively the domain of humans. Computational finance (systems used lo make trading, hedging and investment decisions) has made significant progress in recent years but the focus has been on pricing and hedging complex financial instruments. The proportion of trades that are executed electronically has also increased remarkably in all asset classes, yet market-making has remained relatively labor intensive, lacking theoretical research to underpin practical innovation. In this thesis, we investigate a novel and more intuitive theoretical approach which aims to model the market-making process. The fundamental principle of market-making is inventory management: we propose a unified approach, applicable to all asset classes, that manages the risk of a market-making book automatically. This study reveals several interesting properties which are generally intuitive to most professional market-makers but are hard to precisely encode into an automated strategy. The primary contribution of the methodology is that it enables us to grade different market-making policies and then to search for the optimal one. This can be performed not only for a single asset but also for a portfolio of correlated assets. Furthermore, in the case of a portfolio of assets, the framework enables the market marker to specify each asset's price and market-making dynamics. We then apply the theoretical framework to build an automated market-making algorithm for the European government bonds book at Deutsche Bank. A completely automated market-making book requires numerous components, from price discovery to trade capture and risk analysis, in addition to the inventory management engine: we describe in detail how each component is implemented and integrated within the market-making system. Previous academic studies in this field have generally fallen short of any real application, because they do not have access to real trading environments. The performance of the proposed algorithm is assessed in terms of risk-management and profits or losses on a trading book especially set up for this purpose on the Global Rates Trading desk. The initial three months' performance was mediocre with regards to profits, although we used this period to set the main parameters of the system and further develop weak areas. Thereafter we have had positive results in terms of both risk-management and profits. The contributions to science of this thesis are: (i) a mathematical framework to classify different market-making strategies within a portfolio of assets; (ii) a methodology to search for the optimal strategy for specific order arrival and asset price dynamics; (iii) the real-world application and test of the proposed algorithm.

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