On the Implementation of GNU Prolog

GNU Prolog is a general-purpose implementation of the Prolog language, which distinguishes itself from most other systems by being, above all else, a native-code compiler which produces standalone executables which don't rely on any byte-code emulator or meta-interpreter. Other aspects which stand out include the explicit organization of the Prolog system as a multipass compiler, where intermediate representations are materialized, in Unix compiler tradition. GNU Prolog also includes an extensible and high-performance finite domain constraint solver, integrated with the Prolog language but implemented using independent lower-level mechanisms. This article discusses the main issues involved in designing and implementing GNU Prolog: requirements, system organization, performance and portability issues as well as its position with respect to other Prolog system implementations and the ISO standardization initiative.Comment: 30 pages, 3 figures, To appear in Theory and Practice of Logic Programming (TPLP); Keywords: Prolog, logic programming system, GNU, ISO, WAM, native code compilation, Finite Domain constraint

Design and validation of a platform for electromagnetic fault injection

Security is acknowledged as one of the main challenges in the design and deployment of embedded circuits. Devices need to operate on-the-field safely and correctly, even when at physical reach of potential adversaries. One of the most powerful techniques to compromise the correct functioning of a device are fault injection attacks. They enable an active adversary to trigger errors on a circuit in order to bypass security features or to gain knowledge of security-sensitive information. There are several methods to induce such errors. In this work we focus on the injection of faults through the electromagnetic (EM) channel. In particular, we document our efforts towards building a suitable platform for EM pulse injection. We design a pulse injection circuit that can provide currents over 20 A to an EM injector in order to generate abrupt variations of the EM field on the vicinity of a circuit. We validate the suitability of our platform by applying a well-know attack on an embedded 8-bit microcontroller implementing the AES block cipher. In particular, we show how to extract the AES secret cryptographic keys stored in the device by careful injection of faults during the encryption operations and simple analysis of the erroneous outputs.Peer ReviewedPostprint (published version

A Study of Conductance for a Random, Hierarchically-Structured Material

I consider a mathematical model for the conductance of a system formed by a hi- erarchical network of random bonds. My simulations show that the net conductance converges to a fixed number γ ≈ 0.35337 when the conductances of the bonds are num- bers selected uniformly at random from the interval (0,1). By linearly approximating the model around γ, I derive a new simplified model which I then study in rigorous mathematical detail. I prove a generalized central limit theorem for the new linearized system

Diseño de una plataforma portacoches

La plataforma porta-cotxes dissenyada en aquest treball final de grau es un prototip que permet transportar vehicles avariats de fins a 3500kg. La càrrega es fa mitjançant la part posterior. Aquest disseny es basa bàsicament en dos subestructures. Una primera tipus bolquet accionada per acció d'un cilindre hidràulic telescòpic el qual s'encarrega de donar la inclinació necessària al conjunt per poder carregar el vehicle. La segona estructura es la plataforma que llisca per damunt de l'estructura del bolquet mitjançant un cilindre hidràulic de carrera llarga fins arribar al terra per a que el vehicle pugui ser carregat. Aquesta és la part més important de l'estructura ja que és sobre la qual hi ha contacte directe entre la nostra estructura i el vehicle. Aquesta sofreix grans càrregues ja que un vehicle transmet el seu pes d'una manera molt concentrada. Una vegada la plataforma ja es troba posicionada per a la càrrega del vehicle aquest es puja a la plataforma mitjançant un cabrestant hidràulic que s'acciona mitjançant un control remot, el que permet que l'operari pugui estar a la zona de càrrega sense necessitats de haver d'estar als comandaments de funcionament

球面調和解析に基づくバイノーラル音空間合成法

要約のみTohoku University鈴木陽一課

Binaural synthesis based on the spherical harmonic analysis with compact microphone arrays

Tohoku University鈴木陽

球面調和解析に基づくバイノーラル音空間合成法

要約のみTohoku University鈴木陽一課

Cultural Event Recognition with Visual ConvNets and Temporal Models

This paper presents our contribution to the ChaLearn Challenge 2015 on Cultural Event Classification. The challenge in this task is to automatically classify images from 50 different cultural events. Our solution is based on the combination of visual features extracted from convolutional neural networks with temporal information using a hierarchical classifier scheme. We extract visual features from the last three fully connected layers of both CaffeNet (pretrained with ImageNet) and our fine tuned version for the ChaLearn challenge. We propose a late fusion strategy that trains a separate low-level SVM on each of the extracted neural codes. The class predictions of the low-level SVMs form the input to a higher level SVM, which gives the final event scores. We achieve our best result by adding a temporal refinement step into our classification scheme, which is applied directly to the output of each low-level SVM. Our approach penalizes high classification scores based on visual features when their time stamp does not match well an event-specific temporal distribution learned from the training and validation data. Our system achieved the second best result in the ChaLearn Challenge 2015 on Cultural Event Classification with a mean average precision of 0.767 on the test set.Comment: Initial version of the paper accepted at the CVPR Workshop ChaLearn Looking at People 201