Deformable Shape Completion with Graph Convolutional Autoencoders

The availability of affordable and portable depth sensors has made scanning objects and people simpler than ever. However, dealing with occlusions and missing parts is still a significant challenge. The problem of reconstructing a (possibly non-rigidly moving) 3D object from a single or multiple partial scans has received increasing attention in recent years. In this work, we propose a novel learning-based method for the completion of partial shapes. Unlike the majority of existing approaches, our method focuses on objects that can undergo non-rigid deformations. The core of our method is a variational autoencoder with graph convolutional operations that learns a latent space for complete realistic shapes. At inference, we optimize to find the representation in this latent space that best fits the generated shape to the known partial input. The completed shape exhibits a realistic appearance on the unknown part. We show promising results towards the completion of synthetic and real scans of human body and face meshes exhibiting different styles of articulation and partiality.Comment: CVPR 201

A template description framework for services as a utility for cloud brokerage

Integration and mediation are two core functions that a cloud service broker needs to perform. The description of services involved plays a central role in this endeavour to enable services to be considered as commoditised utilities. We propose a conceptual framework for a cloud service broker based on two parts: a reference architecture for cloud brokers and a service description template that describes the mediated and integrated cloud services. Structural aspects of that template will be identified, formalised in an ontology and mapped onto a set of sublanguages that can be aligned to the cloud development and deployment process

Towards precise completion of deformable shapes

According to Aristotle, “the whole is greater than the sum of its parts”. This statement was adopted to explain human perception by the Gestalt psychology school of thought in the twentieth century. Here, we claim that when observing a part of an object which was previously acquired as a whole, one could deal with both partial correspondence and shape completion in a holistic manner. More specifically, given the geometry of a full, articulated object in a given pose, as well as a partial scan of the same object in a different pose, we address the new problem of matching the part to the whole while simultaneously reconstructing the new pose from its partial observation. Our approach is data-driven and takes the form of a Siamese autoencoder without the requirement of a consistent vertex labeling at inference time; as such, it can be used on unorganized point clouds as well as on triangle meshes. We demonstrate the practical effectiveness of our model in the applications of single-view deformable shape completion and dense shape correspondence, both on synthetic and real-world geometric data, where we outperform prior work by a large margin

Object representation and recognition

One of the primary functions of the human visual system is object recognition, an ability that allows us to relate the visual stimuli falling on our retinas to our knowledge of the world. For example, object recognition allows you to use knowledge of what an apple looks like to find it in the supermarket, to use knowledge of what a shark looks like to swim in th

A computing origami: Optimized code generation for emerging parallel platforms

Ph.DDOCTOR OF PHILOSOPH

Cloud service brokerage: a conceptual ontology-based service description framework

Cloud service brokerage has been identified as a key concern for future Cloud technology research and development. Integration, customization and aggregation are core functions of a Cloud service broker. The need to cater to horizontal and vertical integration in service description languages, horizontally between different providers and vertically across the different Cloud layers, has been well recognized. In this chapter, we propose a conceptual framework for a Cloud service broker in two parts: first, a reference architecture for Cloud service brokers; and second, a rich ontology-based template manipulation framework and operator calculus that describes the mediated and integrated Cloud services, facilitates manipulating their descriptions, and allows both horizontal and vertical dimensions to be covered. Structural aspects of that template will be identified, formalized in an ontology and aligned with the Cloud development and deployment process

On-line Handwritten Signature Verification using Machine Learning Techniques with a Deep Learning Approach

The problem to be solved in this project is to distinguish two signatures from each other, with help of machine learning techniques. The main technique used is the comparison between two signatures and classifying if they are written by the same person (match) or not (no-match). The binary classication problem is then tackled with a few alternatives to better understand it. First by a simple engineered feature, then by the machine learning techniques as logistic regression, multi-layer perceptron and nally a deep learning approach with a convolutional neural network. The evaluation method for the dierent algorithms was a plot of true positive rate (sensitivity) versus false positive rate (fall-out). The results of the alternative algorithms gave a dierent understanding of the problem. The engineered feature performed unexpectedly well. The logistic regression and multi-layer perceptron performed similarly. The main results from the nal model, which was a max-pooling, convolutional neural network, were a true positive rate of 96.7 % and a false positive rate of 0.6 %. The deep learning approach on the signature verication problem shows promising results but there is still room for improvement

Perceiving is Believing. Authentication with Behavioural and Cognitive Factors

Most computer users have experienced login problems such as, forgetting passwords, loosing token cards and authentication dongles, failing that complicated screen pattern once again, as well as, interaction difficulties in usability. Facing the difficulties of non-flexible strong authentication solutions, users tend to react with poor acceptance or to relax the assumed correct use of authentication procedures and devices, rendering the intended security useless. Biometrics can, sort of, solve some of those problems. However, despite the vast research, there is no perfect solution into designing a secure strong authentication procedure, falling into a trade off between intrusiveness, effectiveness, contextual adequacy and security guarantees. Taking advantage of new technology, recent research onmulti-modal, behavioural and cognitive oriented authentication proposals have sought to optimize trade off towards precision and convenience, reducing intrusiveness for the same amount of security. But these solutions also fall short with respect to different scenarios. Users perform currently multiple authentications everyday, through multiple devices, in panoply of different situations, involving different resources and diverse usage contexts, with no "better authentication solution" for all possible purposes. The proposed framework enhances the recent research in user authentication services with a broader view on the problems involving each solution, towards an usable secure authentication methodology combining and exploring the strengths of each method. It will than be used to prototype instances of new dynamic multifactor models (including novel models of behavioural and cognitive biometrics), materializing the PiB (perceiving is believing) authentication. Ultimately we show how the proposed framework can be smoothly integrated in applications and other authentication services and protocols, namely in the context of SSO Authentication Services and OAuth