The role of symmetry in neural networks and their Laplacian spectra

Human and animal nervous systems constitute complexly wired networks that form the infrastructure for neural processing and integration of information. The organization of these neural networks can be analyzed using the so-called Laplacian spectrum, providing a mathematical tool to produce systems-level network fingerprints. In this article, we examine a characteristic central peak in the spectrum of neural networks, including anatomical brain network maps of the mouse, cat and macaque, as well as anatomical and functional network maps of human brain connectivity. We link the occurrence of this central peak to the level of symmetry in neural networks, an intriguing aspect of network organization resulting from network elements that exhibit similar wiring patterns. Specifically, we propose a measure to capture the global level of symmetry of a network and show that, for both empirical networks and network models, the height of the main peak in the Laplacian spectrum is strongly related to node symmetry in the underlying network. Moreover, examination of spectra of duplication-based model networks shows that neural spectra are best approximated using a trade-off between duplication and diversification. Taken together, our results facilitate a better understanding of neural network spectra and the importance of symmetry in neural networks

Vehicle license plate detection and recognition

"December 2013.""A Thesis presented to the Faculty of the Graduate School at the University of Missouri In Partial Fulfillment of the Requirements for the Degree Master of Science."Thesis supervisor: Dr. Zhihai He.In this work, we develop a license plate detection method using a SVM (Support Vector Machine) classifier with HOG (Histogram of Oriented Gradients) features. The system performs window searching at different scales and analyzes the HOG feature using a SVM and locates their bounding boxes using a Mean Shift method. Edge information is used to accelerate the time consuming scanning process. Our license plate detection results show that this method is relatively insensitive to variations in illumination, license plate patterns, camera perspective and background variations. We tested our method on 200 real life images, captured on Chinese highways under different weather conditions and lighting conditions. And we achieved a detection rate of 100%. After detecting license plates, alignment is then performed on the plate candidates. Conceptually, this alignment method searches neighbors of the bounding box detected, and finds the optimum edge position where the outside regions are very different from the inside regions of the license plate, from color's perspective in RGB space. This method accurately aligns the bounding box to the edges of the plate so that the subsequent license plate segmentation and recognition can be performed accurately and reliably. The system performs license plate segmentation using global alignment on the binary license plate. A global model depending on the layout of license plates is proposed to segment the plates. This model searches for the optimum position where the characters are all segmented but not chopped into pieces. At last, the characters are recognized by another SVM classifier, with a feature size of 576, including raw features, vertical and horizontal scanning features. Our character recognition results show that 99% of the digits are successfully recognized, while the letters achieve an recognition rate of 95%. The license plate recognition system was then incorporated into an embedded system for parallel computing. Several TS7250 and an auxiliary board are used to simulIncludes bibliographical references (pages 67-73)

Indexing Techniques for Image and Video Databases: an approach based on Animate Vision Paradigm

[ITALIANO]In questo lavoro di tesi vengono presentate e discusse delle innovative tecniche di indicizzazione per database video e di immagini basate sul paradigma della “Animate Vision” (Visione Animata). Da un lato, sarà mostrato come utilizzando, quali algoritmi di analisi di una data immagine, alcuni meccanismi di visione biologica, come i movimenti saccadici e le fissazioni dell'occhio umano, sia possibile ottenere un query processing in database di immagini più efficace ed efficiente. In particolare, verranno discussi, la metodologia grazie alla quale risulta possibile generare due sequenze di fissazioni, a partire rispettivamente, da un'immagine di query I_q ed una di test I_t del data set, e, come confrontare tali sequenze al fine di determinare una possibile misura della similarità (consistenza) tra le due immagini. Contemporaneamente, verrà discusso come tale approccio unito a tecniche classiche di clustering possa essere usato per scoprire le associazioni semantiche nascoste tra immagini, in termini di categorie, che, di contro, permettono un'automatica pre-classificazione (indicizzazione) delle immagini e possono essere usate per guidare e migliorare il processo di query. Saranno presentati, infine, dei risultati preliminari e l'approccio proposto sarà confrontato con le più recenti tecniche per il recupero di immagini descritte in letteratura. Dall'altro lato, sarà mostrato come utilizzando la precedente rappresentazione “foveata” di un'immagine, risulti possibile partizionare un video in shot. Più precisamente, il metodo per il rilevamento dei cambiamenti di shot si baserà sulla computazione, in ogni istante di tempo, della misura di consistenza tra le sequenze di fissazioni generate da un osservatore ideale che guarda il video. Lo schema proposto permette l'individuazione, attraverso l'utilizzo di un'unica tecnica anziché di più metodi dedicati, sia delle transizioni brusche sia di quelle graduali. Vengono infine mostrati i risultati ottenuti su varie tipologie di video e, come questi, validano l'approccio proposto. / [INGLESE]In this dissertation some novel indexing techniques for video and image database based on “Animate Vision” Paradigm are presented and discussed. From one hand, it will be shown how, by embedding within image inspection algorithms active mechanisms of biological vision such as saccadic eye movements and fixations, a more effective query processing in image database can be achieved. In particular, it will be discussed the way to generate two fixation sequences from a query image I_q and a test image I_t of the data set, respectively, and how to compare the two sequences in order to compute a possible similarity (consistency) measure between the two images. Meanwhile, it will be shown how the approach can be used with classical clustering techniques to discover and represent the hidden semantic associations among images, in terms of categories, which, in turn, allow an automatic pre-classification (indexing), and can be used to drive and improve the query processing. Eventually, preliminary results will be presented and the proposed approach compared with the most recent techniques for image retrieval described in the literature. From the other one, it will be discussed how by taking advantage of such foveated representation of an image, it is possible to partitioning of a video into shots. More precisely, the shot-change detection method will be based on the computation, at each time instant, of the consistency measure of the fixation sequences generated by an ideal observer looking at the video. The proposed scheme aims at detecting both abrupt and gradual transitions between shots using a single technique, rather than a set of dedicated methods. Results on videos of various content types are reported and validate the proposed approach

A generic framework for process execution and secure multi-party transaction authorization

Process execution engines are not only an integral part of workflow and business process management systems but are increasingly used to build process-driven applications. In other words, they are potentially used in all kinds of software across all application domains. However, contemporary process engines and workflow systems are unsuitable for use in such diverse application scenarios for several reasons. The main shortcomings can be observed in the areas of interoperability, versatility, and programmability. Therefore, this thesis makes a step away from domain specific, monolithic workflow engines towards generic and versatile process runtime frameworks, which enable integration of process technology into all kinds of software. To achieve this, the idea and corresponding architecture of a generic and embeddable process virtual machine (ePVM), which supports defining process flows along the theoretical foundation of communicating extended finite state machines, are presented. The architecture focuses on the core process functionality such as control flow and state management, monitoring, persistence, and communication, while using JavaScript as a process definition language. This approach leads to a very generic yet easily programmable process framework. A fully functional prototype implementation of the proposed framework is provided along with multiple example applications. Despite the fact that business processes are increasingly automated and controlled by information systems, humans are still involved, directly or indirectly, in many of them. Thus, for process flows involving sensitive transactions, a highly secure authorization scheme supporting asynchronous multi-party transaction authorization must be available within process management systems. Therefore, along with the ePVM framework, this thesis presents a novel approach for secure remote multi-party transaction authentication - the zone trusted information channel (ZTIC). The ZTIC approach uniquely combines multiple desirable properties such as the highest level of security, ease-of-use, mobility, remote administration, and smooth integration with existing infrastructures into one device and method. Extensively evaluating both, the ePVM framework and the ZTIC, this thesis shows that ePVM in combination with the ZTIC approach represents a unique and very powerful framework for building workflow systems and process-driven applications including support for secure multi-party transaction authorization

Interaction for creative applications with the Kinect v2 device

Human-Computer Interaction (HCI) is a multidisciplinary field of research that designs, evaluates and implements interactive ways of communication between computer systems and people. The evolution of different technologies in the last decades has contributed to the expansion of HCI into other fields of study as computer vision, cognitive science, psychology, industrial design, and also into interactive art. The present document contains a case of HCI in the context of interactive art. In a first step we analyse what kind of interaction can be achieved with the available equipment: a range imaging camera, a computer and a video projector. Then, three range imaging techniques capable of fulfilling our objective are studied and some devices available for purchasing and based on these techniques are compared. Thereafter, we study and compare the two acquired range imaging devices: the Kinect for Windows v1 and the Kinect for Windows v2. In a later step we build our interaction system with the Kinect for Windows v2 and we test it. We use Processing as a programming environment in order to apply creative coding and to try the different types of interaction that this device allows. Finally, with the experience gained in the previous studies and in these test, we present three final interactive programs

Wireless Underwater Broadband and Long Range Communications using Underwater Drones as Data Mules

The underwater communications are essential for the operation and collect large amounts of data (video and images) obtained by Autonomous Underwater Vehicles (AUVs) and remotely controlled underwater vehicles (ROVs) in inspection and monitoring missions at sea. Acoustic waves, despite the high range, allow only narrowband communications, which prevents quick and effective transfer of data. On the other hand, aquatic environment, in particular salt water, severely limits the scope of networks based on electromagnetic waves, having such a range of radius of a few meters. This thesis aims to study and evaluate the use of small vehicles (underwater drones - date mules) capable of transporting data across networks with tolerance to delay (Delay-Tolerant Networks - DTN) between a transmitter and an underwater receiver, taking advantage of high transfer rates at close range. The student must implement a file transfer application that can tolerate high delays in the delivery of information packages. The application will be tested in the underwater environment using the large tank available at INESC TEC and tight cylinder, and compared with simulation results for this scenario. 163/5000 This thesis also presupposes the elaboration of a scientific article for publication in a conference or magazine to disseminate the relevant results of the work.As comunicações subaquáticas são essenciais para a operação e recolha de grandes quantidades de dados (vídeo e imagens) obtidas por Veículos Autónomos Subaquáticos (AUVs) e por veículos subaquáticos controlados remotamente (ROVs) em missões de inspeção e monitorização no mar. As ondas acústicas, apesar do elevado alcance, permitem apenas comunicações de banda estreita, o que inviabiliza a transferência desses dados de forma rápida e eficiente. Por outro lado, o meio aquático, em especial a água salgada, limita severamente o alcance das redes baseadas em ondas eletromagnéticas, tendo estas um raio de alcance de apenas alguns metros. Nesta tese pretende-se estudar e avaliar a utilização de pequenos veículos (drones subaquáticos - data mules) capazes de transportar dados através de redes tolerantes ao atraso (Delay-Tolerant Networks - DTN) entre um emissor e um recetor subaquático, tirando partido das elevadas taxas de transferência a curto alcance. O estudante deverá implementar uma aplicação de transferência de ficheiros capaz de tolerar elevados atrasos na entrega de pacotes de informação. A aplicação será testada em ambiente subaquático recorrendo ao tanque de grandes dimensões disponível no INESC TEC e a cilindros estanques, e comparada com resultados de simulação para esse cenário. Esta tese pressupõe também a elaboração de um artigo científico para publicação em conferência ou revista para disseminação dos resultados relevantes do trabalho

Model-driven generative programming for BIS mobile applications

The burst on the availability of smart phones based on the Android platform calls for cost-effective techniques to generate mobile apps for general purpose, distributed business information systems (BIS). To mitigate this problem our research aims at applying model-driven techniques to automatically generate usable prototypes with a sound, maintainable, architecture. Following three base principles: model-based generation, separation of concerns, paradigm seamlessness, we try to answer the main guiding question – how to reduce development time and cost by transforming a given domain model into an Android application? To answer this question we propose to develop an application that follows a generative approach for mobile BIS apps that will mitigate the identified problems. Its input is a platform independent model (PIM), with business rules specified in OCL (Object Constraint Language). We adopted the Design Science Research methodology, that helps gaining problem understanding, identifying systemically appropriate solutions, and in effectively evaluating new and innovative solutions. To better evaluate our solution, besides resorting to third party tools to test specific components integration, we demonstrated its usage and evaluated how well it mitigates a subset of the identified problems in an observational study (we presented our generated apps to an outside audience in a controlled environment to study our model-based centered and, general apps understandability) and communicated its effectiveness to researchers and practitioners.O grande surto de disponibilidade de dispositivos móveis para a plataforma Android requer, técnicas generativas de desenvolvimento de aplicações para sistemas comuns e/ou distribuídos de informação empresariais/negócio, que otimizem a relação custo-benefício. Para mitigar este problema, esta investigação visa aplicar técnicas orientadas a modelos para, automaticamente, gerar protótipos funcionais de aplicações com uma arquitetura robusta e fácil de manter. Seguindo para tal três princípios base: geração baseada no modelo, separação de aspetos, desenvolvimento sem soturas (sem mudança de paradigma), tentamos dar resposta à pergunta orientadora – como reduzir o tempo e custo de desenvolvimento de uma aplicação Android por transformação de um dado modelo de domínio? De modo a responder a esta questão nós propomos desenvolver uma aplicação que segue uma abordagem generativa para aplicações de informação empresariais/negócio móveis de modo a mitigar os problemas identificados. Esta recebe modelos independentes de plataforma (PIM), com regras de negócio especificadas em OCL (Object Constraint Language). Seguimos a metodologia Design Science Research que ajuda a identificar e perceber o problema, a identificar sistematicamente soluções apropriadas aos problemas e a avaliar mais eficientemente soluções novas e inovadoras. Para melhor avaliar a nossa solução, apesar de recorrermos a ferramentas de terceiros para testar a integração de componentes específicos, também demonstramos a sua utilização, através de estudos experimentais (em um ambiente controlado, apresentamos as nossas aplicações geradas a uma audiência externa que nos permitiu estudar a compreensibilidade baseada e centrada em modelos e, de um modo geral, das aplicações) avaliamos o quanto esta mitiga um subconjunto de problemas identificados e comunicamos a sua eficácia para investigadores e profissionais