• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 25
  • 10
  • 2
  • 2
  • 2
  • 2
  • Tagged with
  • 48
  • 12
  • 11
  • 11
  • 9
  • 8
  • 8
  • 8
  • 7
  • 7
  • 7
  • 6
  • 6
  • 6
  • 6
  • 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.
1

Novel active sweat pores based liveness detection techniques for fingerprint biometrics

Memon, Shahzad Ahmed January 2012 (has links)
Liveness detection in automatic fingerprint identification systems (AFIS) is an issue which still prevents its use in many unsupervised security applications. In the last decade, various hardware and software solutions for the detection of liveness from fingerprints have been proposed by academic research groups. However, the proposed methods have not yet been practically implemented with existing AFIS. A large amount of research is needed before commercial AFIS can be implemented. In this research, novel active pore based liveness detection methods were proposed for AFIS. These novel methods are based on the detection of active pores on fingertip ridges, and the measurement of ionic activity in the sweat fluid that appears at the openings of active pores. The literature is critically reviewed in terms of liveness detection issues. Existing fingerprint technology, and hardware and software solutions proposed for liveness detection are also examined. A comparative study has been completed on the commercially and specifically collected fingerprint databases, and it was concluded that images in these datasets do not contained any visible evidence of liveness. They were used to test various algorithms developed for liveness detection; however, to implement proper liveness detection in fingerprint systems a new database with fine details of fingertips is needed. Therefore a new high resolution Brunel Fingerprint Biometric Database (B-FBDB) was captured and collected for this novel liveness detection research. The first proposed novel liveness detection method is a High Pass Correlation Filtering Algorithm (HCFA). This image processing algorithm has been developed in Matlab and tested on B-FBDB dataset images. The results of the HCFA algorithm have proved the idea behind the research, as they successfully demonstrated the clear possibility of liveness detection by active pore detection from high resolution images. The second novel liveness detection method is based on the experimental evidence. This method explains liveness detection by measuring the ionic activities above the sample of ionic sweat fluid. A Micro Needle Electrode (MNE) based setup was used in this experiment to measure the ionic activities. In results, 5.9 pC to 6.5 pC charges were detected with ten NME positions (50μm to 360 μm) above the surface of ionic sweat fluid. These measurements are also a proof of liveness from active fingertip pores, and this technique can be used in the future to implement liveness detection solutions. The interaction of NME and ionic fluid was modelled in COMSOL multiphysics, and the effect of electric field variations on NME was recorded at 5μm -360μm positions above the ionic fluid.
2

Verification of liveness properties on hybrid dynamical systems

Carter, Rebekah January 2013 (has links)
A hybrid dynamical system is a mathematical model for a part of the real world where discrete and continuous parts interact with each other. Typically such systems are complex, and it is difficult to know how they will behave for general parameters and initial conditions. However, the method of formal verification gives us the ability to prove automatically that certain behaviour does or does not happen for a range of parameters in a system. The challenge is then to define suitable methods for proving properties on hybrid systems.This thesis looks at using formal verification for proving liveness properties on hybrid systems: a liveness property says that something good eventually happens in the system. This work presents the theoretical background and practical application of various methods for proving and disproving inevitability properties (a type of liveness) in different classes of hybrid systems. The methods combine knowledge of dynamical behaviour of a system with the brute-force approach of model checking, in order to make the most of the benefits of both sides. The work on proving liveness properties is based on abstraction of dynamical systems to timed automata. This thesis explores the limits of a pre-defined abstraction method, adds some dynamical knowledge to the method, and shows that this improvement makes liveness properties provable in certain continuous dynamical systems. The limits are then pushed further to see how this method can be used for piecewise-continuous dynamical systems. The resulting algorithms are implemented for both classes of systems.In order to disprove liveness properties in hybrid systems a novel framework is proposed, using a new property called deadness. Deadness is a dynamically-aware property of the hybrid system which, if true, disproves the liveness property by means of a finite execution: we usually require an infinite execution to disprove a liveness property. An algorithm is proposed which uses dynamical properties of hybrid systems to derive deadness properties automatically, and the implementation of this algorithm is discussed and applied to a simplified model of an oilwell drillstring.
3

Reconsidering "Liveness":Interactivity and Presence in Hybrid Virtual Reality Theatre

Peterson, Anne Cordelia January 2020 (has links)
No description available.
4

CMD+FN

Macaranas, Marc 01 January 2019 (has links)
No description available.
5

Live Mobile Video Interaction : Inventing and investigating technology, formats and applications

Mughal, Mudassar Ahmad January 2015 (has links)
The convergence of inexpensive video-enabled mobile phones, high-speed mobile data networks and ubiquitous sensing devices opens up a new design space called “live mobile video interaction”. It gives rise to a new genre of applications concerning live mobile video production, which can be seen as an instance of the said space. In this work we are particularly interested to explore potential technical challenges and opportunities presented by “live mobile video interaction”. We started our investigation by studying two existing prototypes from the said genre i.e. the Instant Broadcasting System (IBS) and the Mobile Vision Mixer (MVM). We studied their applicability for amateur users of collaborative mobile video production tools and the problems caused by inherent communication delays in the Internet. We acquired initial user feedback and conducted technical tests on Instant Broadcasting System (IBS) and Mobile Vision Mixer (MVM). Our results indicate that lack of synchronisation among video streams causes problems for directors in such systems that were not present in professional systems. We also identified two distinct video production modes depending on visual access of the director to the event that is being filmed. Based on our study we proposed technical design suggestions and indications on how to solve the synchronisation problems in respective mixing modes. We also proposed an algorithm for frame-rate exclusive synchronisation management of live streams in a collaborative mobile production environment. We further probed the design space using the research through design method, which resulted in a fully functional prototype system called “Livenature” that would incite an emotional connection that exists between people and the places they cherish. Further investigation of Livenature allowed us to produce detailed studies about experiential and technical aspects of the system, thus revealing phenomenological and technical dimensions of the design space.
6

Simulating Distributed Executions in Kompact / Simulering av distribuerad exekvering i Kompac

Mallo Bakken, Johan January 2022 (has links)
Distributed systems are complex systems that offer highly scalable and reliable services. With that complexity comes the difficulty of developing and testing such systems as they are highly non-deterministic. Approaches like model checking are used to verify models of distributed systems formally, but the insufficient correlation between model and implementation, as well as the state-explosion problem, makes this approach sub-optimal. In real-world systems, transient sequences of events could result in failures, but these events can be both difficult to detect and reproduce. This thesis addresses the problem of testing distributed systems by proposing a way to test these systems through a discrete event simulator that is integrated into the distributed runtime Kompact. The simulator can run on real message-passing implementations and provides precise control over a simulation through what is referred to as fine-grained sequences of events. The flexibility of the simulator is demonstrated by using it to simulate and reproduce faulty behavior in the Raft consensus algorithm. Through state monitoring, the state transitions of such a simulation allow us to analyze and suspect the occurrence of liveness issues. / Distribuerade system är komplexa system som erbjuder mycket skalbara och pålitliga tjänster. Med den komplexiteten kommer svårigheten att utveckla och testa sådana system eftersom de är mycket icke-deterministiska. Tillvägagångssätt som model kontroll används för att verifiera modeller av distribuerade system formellt, men otillräcklig korrelation mellan modell och implementering, liksom tillståndsexplosionsproblem, gör detta tillvägagångssätt suboptimalt. I den verkliga världen system, kan övergående händelseförlopp resultera i fel, men dessa händelser kan vara både svåra att upptäcka och reproducera. Denna avhandling tar upp problemet med att testa distribuerade system genom att föreslå ett sätt att testa dessa system genom en diskret händelsesimulator som är integrerad i den distribuerade runtime Kompact. Simulatorn kan köras på riktiga meddelande-passerar implementeringar och ger exakt kontroll över en simulering genom vad som kallas finkorniga händelseförlopp. Flexibiliteten hos simulatorn demonstreras genom att använda den för att simulera och reproducera felaktiga beteende i konsensusalgoritm Raft. Genom statlig övervakning, staten övergångar av en sådan simulering gör att vi kan analysera och misstänka händelsen av livlighetsfrågor.
7

Processing Der Prozess/Proces

Horáková, Jana 07 June 2011 (has links) (PDF)
The paper focuses on the possibilities and potential of connecting live performance with new media. Our attempt is to find alternative strategies for theatre/performance relations with media, in this case digital media, by means of placing the theatre/performance within contemporary art production, developing strategies of production, which is developing a culture of usage. “In this new form of culture, which one might call a culture of use or a culture of activity, the artwork functions as the temporary terminal of a network of interconnected elements, like a narrative that extends and reinterprets preceding narratives.” [Nicolas Bourriaud: Postproduction, New York 2002] The project we are going to introduce is based on collaborative research, in which artistic and scientific approaches overlap and fuse.
8

Liveproduktion med Twitch som ett substitut för en allseende Gud

Österlind, Jerker January 2021 (has links)
En undersökning av hur online-exponering påverkar kreativa processer. Genom att arbeta i en öppen live-stream har Jerker Österlind inför publik skapat en EP under 30 Twitch-sändningar. Denna text utforskar effekterna av att bjuda in åskådare till vad som brukar ske bakom stängda dörrar, hur det musikaliska resultatet påverkas, hur arbetsprocessen förändras och funderingar om hur livestreaming kan ge nya möjligheter för marknadsföring och karriär. https://open.spotify.com/album/18uGeyxD00Ssayi1exCCJo?si=qbFel0xUTaeF4rXiwlR2GQ / An inquiry about the impacts of online exposure on creative processes. By working in a public livestream, Jerker Österlind has made an EP in front of an audience during 30 Twitch broadcasts. This text explores the effects of inviting an audience to things that usually take place behind closed doors, how the musical result is affected, how work methods are changed and how livestreaming can open up new opportunities for marketing and careers.  https://open.spotify.com/album/18uGeyxD00Ssayi1exCCJo?si=qbFel0xUTaeF4rXiwlR2GQ / <p>Arbetet presenteras i form av en EP med fem spår. Alla instrument är spelade av J. Österlind.</p><p>Musiken kan höras här:</p><p>https://open.spotify.com/album/18uGeyxD00Ssayi1exCCJo?si=qbFel0xUTaeF4rXiwlR2GQ</p><p>och här:</p><p>https://mudbody.bandcamp.com/album/underachieve-ep</p>
9

Processing Der Prozess/Proces

Horáková, Jana 07 June 2011 (has links)
The paper focuses on the possibilities and potential of connecting live performance with new media. Our attempt is to find alternative strategies for theatre/performance relations with media, in this case digital media, by means of placing the theatre/performance within contemporary art production, developing strategies of production, which is developing a culture of usage. “In this new form of culture, which one might call a culture of use or a culture of activity, the artwork functions as the temporary terminal of a network of interconnected elements, like a narrative that extends and reinterprets preceding narratives.” [Nicolas Bourriaud: Postproduction, New York 2002] The project we are going to introduce is based on collaborative research, in which artistic and scientific approaches overlap and fuse.
10

Verifying Absence of ∞ Loops in Parameterized Protocols

Saksena, Mayank January 2008 (has links)
<p>The complex behavior of computer systems offers many challenges for <i>formal verification</i>. The analysis quickly becomes difficult as the number of participating processes increases.</p><p>A <i>parameterized system</i> is a family of systems parameterized on a number <i>n</i>, typically representing the number of participating processes. The <i>uniform verification problem</i> — to check whether a property holds for each instance — is an infinite-state problem. The automated analysis of parameterized and infinite-state systems has been the subject of research over the last 15–20 years. Much of the work has focused on safety properties. Progress in verification of liveness properties has been slow, as it is more difficult in general.</p><p>In this thesis, we consider verification of parameterized and infinite-state systems, with an emphasis on liveness, in the verification framework called <i>regular model checking (RMC)</i>. In RMC, states are represented as words, sets of states as regular expressions, and the transition relation as a regular relation.</p><p>We extend the automata-theoretic approach to RMC. We define a <i>specification logic</i> sufficiently strong to specify systems representable using RMC, and linear temporal logic properties of such systems, and provide an automatic translation from a specification into an analyzable model.</p><p>We develop <i>acceleration techniques</i> for RMC which allow more uniform and automatic verification than before, with greater power. Using these techniques, we succeed to verify safety and liveness properties of parameterized protocols from the literature.</p><p>We present a novel <i>reachability based</i> verification method for verification of liveness, in a general setting. We implement the method for RMC, with promising results.</p><p>Finally, we develop a framework for the verification of dynamic networks based on graph transformation, which generalizes the systems representable in RMC. In this framework we verify the latest version of the DYMO routing protocol, currently being considered for standardization by the IETF.</p>

Page generated in 0.0735 seconds