Search results for " Computer Science"
showing 10 items of 3983 documents
Iterative Learning Applied to Hydraulic Pressure Control
2018
This paper addresses a performance limiting phenomenon that may occur in the pressure control of hydraulic actuators subjected to external velocity disturbances. It is demonstrated that under certain conditions a severe peaking of the control error may be observed that significantly degrades the performance of the system due to the presence of nonlinearities. The phenomenon is investigated numerically and experimentally using a system that requires pressure control of two hydraulic cylinders. It is demonstrated that the common solution of feed forwarding the velocity disturbance is not effective in reducing the peaking that occurs as a result of this phenomenon. To improve the system perfor…
Evaluation de la pertinence dans un système de recommandation sémantique de nouvelles économiques
2014
Today in the commercial and financial sectors, staying informed about economic news is crucial and involves targeting good articles to read, because the huge amount of information. To address this problem, we propose an innovative article recommendation system, based on the integration of a semantic description of articles and on a knowledge ontological model. We support our recommendation system on an intrinsically efficient vector model that we have perfected to overcome the confusion existing in models between the concepts of similarity and relevancy that does not take into account the effects of the difference in the accuracy of the semantic descriptions precision between profiles and a…
Kohn-Sham Decomposition in Real-Time Time-Dependent Density-Functional Theory An Efficient Tool for Analyzing Plasmonic Excitations
2017
The real-time-propagation formulation of time-dependent density-functional theory (RT-TDDFT) is an efficient method for modeling the optical response of molecules and nanoparticles. Compared to the widely adopted linear-response TDDFT approaches based on, e.g., the Casida equations, RT-TDDFT appears, however, lacking efficient analysis methods. This applies in particular to a decomposition of the response in the basis of the underlying single-electron states. In this work, we overcome this limitation by developing an analysis method for obtaining the Kohn-Sham electron-hole decomposition in RT-TDDFT. We demonstrate the equivalence between the developed method and the Casida approach by a be…
Active lighting applied to three-dimensional reconstruction of specular metallic surfaces by polarization imaging
2006
International audience; In the field of industrial vision, the three-dimensional inspection of highly reflective metallic objects is still a delicate task. We deal with a new automated three-dimensional inspection system based on polarization analysis. We first present an extension of the shape-from-polarization method for dielectric surfaces to metallic surfaces. Then, we describe what we believe to be a new way of solving the ambiguity concerning the normal orientation with an active lighting system. Finally, applications to shape-defect detection are discussed, and the efficiency of the system to discriminate defects on specular metallic objects made by stamping and polishing is presente…
Toward Quaternary QCA : Novel Majority and XOR Fuzzy Gates
2022
As an emerging nanotechnology, quantum-dot cellular automata (QCA) has been considered an alternative to CMOS technology that suffers from problems such as leakage current. Moreover, QCA is suitable for multi-valued logic due to the simplicity of implementing fuzzy logic in a way much easier than CMOS technology. In this paper, a quaternary cell is proposed with two isolated layers because of requiring three particles to design this quaternary cell. Moreover, due to the instability of the basic gates, the three particles cannot be placed in one layer. The first layer of the proposed two-layer cell includes a ternary cell and the second one includes a binary cell. It is assumed that the over…
Information Security Risk Assessments following Cybersecurity Breaches : The Mediating Role of Top Management Attention to Cybersecurity
2023
Information Systems (IS) research on managerial response to cybersecurity breaches has largely focused on externally oriented actions such as customer redressal and crisis response. Within the firm itself, a breach may be a symptom of systematic problems, and a narrow, siloed focus on only fixing immediate issues through technical fixes and controls might preclude other managerial actions to ensure future cybersecurity. Towards this end, Information Security Risk Assessments (ISRA) can help surface other vulnerabilities following a breach. While the role of governance in such exercises is emphasized in standards, it is undertheorized in IS research and lacks empirical evidence. We draw on t…
Energie informatique et choix de matériel
1995
The choice of computers been made according to a minimax: one chooses the most powerful computer in the less powerful category. We show here that, in a simple case, if one takes into account the time of equipment utilization, this rule can be given in cause. We study then a case more complicated including some technical parameters like the case of multiprocessor machine and including other human parameters like the intensity of task submission.
Numerical and Experimental Study of a Novel Concept for Hydraulically Controlled Negative Loads
2016
This paper presents a numerical and experimental investigation of a novel concept that eliminates oscillations in hydraulic systems containing a counterbalance valve in series with a pressure compensated flow supply. The concept utilizes a secondary circuit where a low-pass filtered value of the load pressure is generated and fed back to the compensator of the flow supply valve. The novel concept has been implemented on a single boom actuated by a cylinder. A nonlinear model of the system has been developed and an experimental verification shows good correspondence between the model and the real system. The model is used for a parameter study on the novel concept. From the study it is found…
Linear Types for Higher Order Processes with First Class Directed Channels
1995
Abstract We present a small programming language for distributed systems based on message passing processes. In contrast to similar languages, channels are one-to-one connections between a unique sender and a unique receiver process. Process definitions and channels are first class values and the topology of process systems can change dynamically. The operational semantics of the language is defined by means of graph rewriting rules. A static type system based on the notion of linear types ensures that channels are always used as one-to-one connections.
Modal Consequence Relations Extending S4.3: An Application of Projective Unification
2016
We characterize all finitary consequence relations over $\mathbf{S4.3}$ , both syntactically, by exhibiting so-called (admissible) passive rules that extend the given logic, and semantically, by providing suitable strongly adequate classes of algebras. This is achieved by applying an earlier result stating that a modal logic $L$ extending $\mathbf{S4}$ has projective unification if and only if $L$ contains $\mathbf{S4.3}$ . In particular, we show that these consequence relations enjoy the strong finite model property, and are finitely based. In this way, we extend the known results by Bull and Fine, from logics, to consequence relations. We also show that the lattice of consequence relation…