Residual Vibration Reduction in Computer Controlled Machines

Control of machines that exhibit flexibility becomes important when designers attempt to push the state of the art with faster, lighter machines. Three steps are necessary for the control of a flexible planet. First, a good model of the plant must exist. Second, a good controller must be designed. Third, inputs to the controller must be constructed using knowledge of the system dynamic response. There is a great deal of literature pertaining to modeling and control but little dealing with the shaping of system inputs. Chapter 2 examines two input shaping techniques based on frequency domain analysis. The first involves the use of the first deriviate of a gaussian exponential as a driving function template. The second, acasual filtering, involves removal of energy from the driving functions at the resonant frequencies of the system. Chapter 3 presents a linear programming technique for generating vibration-reducing driving functions for systems. Chapter 4 extends the results of the previous chapter by developing a direct solution to the new class of driving functions. A detailed analysis of the new technique is presented from five different perspectives and several extensions are presented. Chapter 5 verifies the theories of the previous two chapters with hardware experiments. Because the new technique resembles common signal filtering, chapter 6 compares the new approach to eleven standard filters. The new technique will be shown to result in less residual vibrations, have better robustness to system parameter uncertainty, and require less computation than other currently used shaping techniques.

Tactile Sensing for Mechatronics: A State of the Art Survey

Lee M.H. and Nicholls H.R., Tactile Sensing for Mechatronics: A State of the Art Survey, Mechatronics, 9, Jan 1999, pp1-31.

ART: An ontology based tool for the translation of papers into Semantic Web format

To be presented at SIG/ISMB07 ontology workshop: http://bio-ontologies.org.uk/index.php To be published in BMC Bioinformatics. Sponsorship: JISC

High current density induced damage mechanisms in electronic solder joints: a state-of-the-art review

High current density induced damages such as electromigration in the on-chip interconnection /metallization of Al or Cu has been the subject of intense study over the last 40 years. Recently, because of the increasing trend of miniaturization of the electronic packaging that encloses the chip, electromigration as well as other high current density induced damages are becoming a growing concern for off-chip interconnection where low melting point solder joints are commonly used. Before long, a huge number of publications have been explored on the electromigration issue of solder joints. However, a wide spectrum of findings might confuse electronic companies/designers. Thus, a review of the high current induced damages in solder joints is timely right this moment. We have selected 6 major phenomena to review in this paper. They are (i) electromigration (mass transfer due electron bombardment), (ii) thermomigration (mass transfer due to thermal gradient), (iii) enhanced intermetallic compound growth, (iv) enhanced current crowding, (v) enhanced under bump metallisation dissolution and (vi) high Joule heating and (vii) solder melting. the damage mechanisms under high current stressing in the tiny solder joint, mentioned in the review article, are significant roadblocks to further miniaturization of electronics. Without through understanding of these failure mechanisms by experiments coupled with mathematical modeling work, further miniaturization in electronics will be jeopardized

The idea, the machine, and the art: word and image in the 21st century

Taking in recent advances in neuroscience and digital technology, Gander and Garland assess the state of the inter-arts in America and the Western world, exploring and questioning the primacy of affect in an increasingly hypertextual everyday environment. In this analysis they signal a move beyond W. J. T. Mitchell’s coinage of the ‘imagetext’ to an approach that centres the reader-viewer in a recognition, after John Dewey, of ‘art as experience’. New thinking in cognitive and computer sciences about the relationship between the body and the mind challenges any established definitions of ‘embodiment’, ‘materiality’, ‘virtuality’ and even ‘intelligence, they argue, whilst ‘Extended Mind Theory’, they note, marries our cognitive processes with the material forms with which we engage, confirming and complicating Marshall McLuhan’s insight, decades ago, that ‘all media are “extensions of man”’. In this chapter, Gander and Garland open paths and suggest directions into understandings and critical interpretations of new and emerging imagetext worlds and experiences.

Computing, Design, Art: Reflections on an Innovative Moment in History

The paper is concerned with the role of art and design in the history and philosophy of computing. It offers insights arising from research into a period in the 1960s and 70s, particularly in the UK, when computing became more available to artists and designers, focusing on John Lansdown (1929-1999) and Bruce Archer (1922-2005) in London. Models of computing interacted with conceptualisations of art, design and related creative activities in important ways.

Digital Debris of Internet Art: An Allegorical and Entropic Resistance to the Epistemology of Search

This Ph.D., by thesis, proposes a speculative lens to read Internet Art via the concept of digital debris. In order to do so, the research explores the idea of digital debris in Internet Art from 1993 to 2011 in a series of nine case studies. Here, digital debris are understood as words typed in search engines and which then disappear; bits of obsolete codes which are lingering on the Internet, abandoned website, broken links or pieces of ephemeral information circulating on the Internet and which are used as a material by practitioners. In this context, the thesis asks what are digital debris? The thesis argues that the digital debris of Internet Art represent an allegorical and entropic resistance to the what Art Historian David Joselit calls the Epistemology of Search. The ambition of the research is to develop a language in-between the agency of the artist and the autonomy of the algorithm, as a way of introducing Internet Art to a pluridisciplinary audience, hence the presence of the comparative studies unfolding throughout the thesis, between Internet Art and pionners in the recycling of waste in art, the use of instructions as a medium and the programming of poetry. While many anthropological and ethnographical studies are concerned with the material object of the computer as debris once it becomes obsolete, very few studies have analysed waste as discarded data. The research shifts the focus from an industrial production of digital debris (such as pieces of hardware) to obsolete pieces of information in art practice. The research demonstrates that illustrations of such considerations can be found, for instance, in Cory Arcangel’s work Data Diaries (2001) where QuickTime files are stolen, disassembled, and then re-used in new displays. The thesis also looks at Jodi’s approach in Jodi.org (1993) and Asdfg (1998), where websites and hyperlinks are detourned, deconstructed, and presented in abstract collages that reveals the architecture of the Internet. The research starts in a typological manner and classifies the pieces of Internet Art according to the structure at play in the work. Indeed if some online works dealing with discarded documents offer a self-contained and closed system, others nurture the idea of openness and unpredictability. The thesis foregrounds the ideas generated through the artworks and interprets how those latter are visually constructed and displayed. Not only does the research questions the status of digital debris once they are incorporated into art practice but it also examine the method according to which they are retrieved, manipulated and displayed to submit that digital debris of Internet Art are the result of both semantic and automated processes, rendering them both an object of discourse and a technical reality. Finally, in order to frame the serendipity and process-based nature of the digital debris, the Ph.D. concludes that digital debris are entropic . In other words that they are items of language to-be, paradoxically locked in a constant state of realisation.

Postsecondary Artist Teachers' Responses to Computer Technology in Their Drawing Pedagogy

While the influence of computer technology has been widely studied in a variety of contexts, the drawing teaching studio is a particularly interesting context because of the juxtaposition of traditional medium and computer technology. For this study, 5 Canadian postsecondary teachers engaged in a 2-round Delphi interview process to discuss their responses to computer technology on their drawing pedagogy. Data sources included transcribed interviews. Findings indicated that artist teachers are both cautious to embrace and curious to explore appropriate use of computer technology on their drawing pedagogy. Artist teachers are both critical and optimistic about the influence of computer technology.

Temporalité et surveillance dans l'art de David Rokeby

Pour respecter les droits d'auteur, la version électronique de ce mémoire à été dépouillée de ses documents visuels et audio-visuels. La version intégrale du mémoire a été déposée au Service de la gestion des documents et des archives de l'Université de Montréal.

Le cinéma omnistéréo ou l'art d'avoir des yeux tout le tour de la tête

Cette thèse s'intéresse à des aspects du tournage, de la projection et de la perception du cinéma stéréo panoramique, appelé aussi cinéma omnistéréo. Elle s'inscrit en grande partie dans le domaine de la vision par ordinateur, mais elle touche aussi aux domaines de l'infographie et de la perception visuelle humaine. Le cinéma omnistéréo projette sur des écrans immersifs des vidéos qui fournissent de l'information sur la profondeur de la scène tout autour des spectateurs. Ce type de cinéma comporte des défis liés notamment au tournage de vidéos omnistéréo de scènes dynamiques, à la projection polarisée sur écrans très réfléchissants rendant difficile l'estimation de leur forme par reconstruction active, aux distorsions introduites par l'omnistéréo pouvant fausser la perception des profondeurs de la scène. Notre thèse a tenté de relever ces défis en apportant trois contributions majeures. Premièrement, nous avons développé la toute première méthode de création de vidéos omnistéréo par assemblage d'images pour des mouvements stochastiques et localisés. Nous avons mis au point une expérience psychophysique qui montre l'efficacité de la méthode pour des scènes sans structure isolée, comme des courants d'eau. Nous proposons aussi une méthode de tournage qui ajoute à ces vidéos des mouvements moins contraints, comme ceux d'acteurs. Deuxièmement, nous avons introduit de nouveaux motifs lumineux qui permettent à une caméra et un projecteur de retrouver la forme d'objets susceptibles de produire des interréflexions. Ces motifs sont assez généraux pour reconstruire non seulement les écrans omnistéréo, mais aussi des objets très complexes qui comportent des discontinuités de profondeur du point de vue de la caméra. Troisièmement, nous avons montré que les distorsions omnistéréo sont négligeables pour un spectateur placé au centre d'un écran cylindrique, puisqu'elles se situent à la périphérie du champ visuel où l'acuité devient moins précise.

An Alternative Approach To Computer System Security Monitoring And Enhancement Through System Call Sequence Analysis

Modern computer systems are plagued with stability and security problems: applications lose data, web servers are hacked, and systems crash under heavy load. Many of these problems or anomalies arise from rare program behavior caused by attacks or errors. A substantial percentage of the web-based attacks are due to buffer overflows. Many methods have been devised to detect and prevent anomalous situations that arise from buffer overflows. The current state-of-art of anomaly detection systems is relatively primitive and mainly depend on static code checking to take care of buffer overflow attacks. For protection, Stack Guards and I-leap Guards are also used in wide varieties.This dissertation proposes an anomaly detection system, based on frequencies of system calls in the system call trace. System call traces represented as frequency sequences are profiled using sequence sets. A sequence set is identified by the starting sequence and frequencies of specific system calls. The deviations of the current input sequence from the corresponding normal profile in the frequency pattern of system calls is computed and expressed as an anomaly score. A simple Bayesian model is used for an accurate detection.Experimental results are reported which show that frequency of system calls represented using sequence sets, captures the normal behavior of programs under normal conditions of usage. This captured behavior allows the system to detect anomalies with a low rate of false positives. Data are presented which show that Bayesian Network on frequency variations responds effectively to induced buffer overflows. It can also help administrators to detect deviations in program flow introduced due to errors.

State-of-the-Art: Transformation Invariant Descriptors

As the popularity of digital videos increases, a large number illegal videos are being generated and getting published. Video copies are generated by performing various sorts of transformations on the original video data. For effectively identifying such illegal videos, the image features that are invariant to various transformations must be extracted for performing similarity matching. An image feature can be its local feature or global feature. Among them, local features are powerful and have been applied in a wide variety of computer vision aplications .This paper focuses on various recently proposed local detectors and descriptors that are invariant to a number of image transformations.

Evaluating the state of the art of parallel programming systems

This paper describes our plans to evaluate the present state of affairs concerning parallel programming and its systems. Three subprojects are proposed: a survey among programmers and scientists, a comparison of parallel programming systems using a standard set of test programs, and a wiki resource for the parallel programming community - the Parawiki. We would like to invite you to participate and turn these subprojects into true community efforts.

Computer-mediated communication and time pressure induce higher cardiovascular responses in the preparatory and execution phases of cooperative tasks

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