1,907 research outputs found
Crash dieting: The effects of eating and drinking on driving performance
No full textPrevious research suggests that compared to mobile phone use, eating and drinking while driving is more common and is seen as lower risk by drivers. Nevertheless, snacking at the wheel can affect vehicle control to a similar extent as using a hands-free phone, and is actually a causal factor in more crashes. So far, though, there has not been a controlled empirical study of this problem. In an effort to fill this gap in the literature, we used the Brunel University Driving Simulator to test participants on a typical urban scenario. At designated points on the drive, which coincided with instructions to eat or drink, a critical incident was simulated by programming a pedestrian to walk in front of the car. Whilst the driving performance variables measured were relatively unaffected by eating and drinking, perceived driver workload was significantly higher and there were more crashes in the critical incident when compared to driving normally. Despite some methodological limitations of the study, when taken together with previous research, the evidence suggests that the physical demands of eating and drinking while driving can increase the risk of a crash
Interview with Mahfoud Nahnah
No full textلقاء مع زعيم حزب حركة مجتمع السلم بالجزائر محفوظ نحناح المرشح في الإنتخابات الجزائرية حول المرشحين في تلك الإنتخابات. أجرى هذا اللقاء إبراهيم عابدين.An interview with the leader of the Islamist party Movement of Society for Peace in Algeria Mahfoud Nahnah and who is a candidate in the Algerian elections, about the other candidates in these elections. Interview conducted by Ibrahim Abdeen
Mahfoud Bennoune (1936-2004) : un témoignage
No full text« Un homme bon. Ce qui est peut-être, encore mieux, un “dur”»: c’est en ces termes qu’un ami britannique, spécialiste du monde arabe, qui a été aussi un ami de longue date de Mahfoud Bennoune, a réagi à la nouvelle de sa mort. Je partage entièrement cette appréciation, tout en ayant des choses à y ajouter. Ayant commencé mes propres recherches sur l’Algérie en 1972, j’ai pris connaissance des premiers écrits de Mahfoud Bennoune assez tôt, mais j’ai dû attendre plus de vingt ans avant de faire..
Síria en primera persona: L'experiència d'un sirià molt català
No full textLa Dra. Àngels Ballarín, metgessa de família EAP Vic, entrevista a Ibrahim Mahfoud, metge de família ACUT Osona
Accueil de M. El Mahfoud Asmhri (Institut Royal de la Culture Amazighe, Rabat, Maroc)
No full textLe Centre Camille Jullian (CCJ, UMR 7299) a le plaisir d’accueillir du 27 novembre au 11 décembre 2023 : M. El Mahfoud Asmhri, directeur de recherche à l'Institut Royal de la Culture Amazighe à Rabat (Maroc). Durant son séjour, M. El Mahfoud Asmhri effectuera des recherches bibliographiques dans ses domaines d’intérêts, à savoir l’art rupestre de la période libyco-berbère et rencontrera les différents chercheurs spécialistes de l'histoire et l'archéologie du Maghreb antique. La mobili..
Metadata Management in Data Lake Environments: a Survey
No full textData lakes are storage repositories that contain large amounts of data in its native format; either structured ssemi-structured or unstructured, to be used when needed. Data lakes are open to a wide range of use cases such as carrying out advanced analytics, extracting knowledge patterns, etc. However, simply dumping all the data into a data lake would only lead to a so-called data swamp. To prevent such a situation, enterprises can adopt best practices among which to build and maintain metadata. In recent years there has been a growing body of research about managing metadata in data lake environments. Existing research efforts deal separately with different activities such as metadata modeling, metadata capture and extraction, metadata usage, etc. Nevertheless, despite its importance, a global view about the research landscape about metadata management for data lakes is still missing. This survey congre- gates different facets of metadata management in data lakes and presents a global view along with the technological impli- cations and the required features for building successful meta- data management systems. Besides, this survey summarizes and discusses research gaps, open problems and main chal- lenges facing both industrialists and academics. This survey pertains to the broader field of Big Data and especially to the data platforms that manage enterprise big data assets. Furthermore, considering the parallels between data lakes and digital libraries regarding their dependence on metadata for content management, this study could offer valuable insights to the digital library community, offering them a technological outlook on metadata management
Development of an eco-binder / geopolymer based on alternative materials : One-part-Geopolymer, optimization, durability, modeling
No full textAujourd’hui, un intérêt croissant dans les domaines de la construction est donné à la construction durable qui se doit d’être rationnelle et écologique. Une des pistes d’innovation et de recherche concerne la valorisation des matériaux alternatives et la substitution des ciments ordinaires par d’autres types de liants telles que les géopolymères. La combinaison de la valorisation des matériaux alternatifs et des liants géopolymères nous permettra dans le futur de proposer une nouvelle génération de matériaux bas carbone. Pour répondre à ce besoin d’innovation, l’objectif de notre travail de recherche est la valorisation de sédiments de dragage dans un liant géopolymère de type One-Part-Geopolymer. Ces travaux de recherches permettent à travers les formulations développées de substituer des cendres volantes par des sédiments de dragage considérés comme des matériaux locaux dont l’empreinte carbone est assez basse. De plus, nous avons simplifié la méthode de formulation, en utilisant la méthode Just-Add-Water qui facilitera l’utilisation des géopolymères à l’échelle industrielle.Dans nos travaux de recherche, une optimisation du pourcentage de sédiments et d’activateurs alcalins a été réalisée afin de choisir une formulation de mortier optimale pour chaque pourcentage de sédiments incorporés en substitution des cendres volantes (0, 15, 30 et 50%). Les caractérisations mécaniques et physicochimiques ont montré que les sédiments améliorent les performances mécaniques et les propriétés physicochimiques des géopolymères. Les résultats ainsi ont montré que les sédiments de dragage peuvent être utilisé comme source d’aluminosilicates dans un liant géopolymère.Afin de valider nos résultats, une étude de durabilité a été réalisée sur plusieurs formulations optimales. Ces matériaux étudiés ont montré de bonnes performances en termes de stabilité volumique (retrait endogène, retrait de séchage, gel/dégel), de stabilité chimique (carbonatation, attaque sulfatique externe, réaction sulfatique interne) et de stabilité environnementale (lixiviations). L’évolution de phénomènes physiques tel que le retrait a été davantage lié à la distribution porale qu'à la perte de masse. L’ajout de sédiments augmente en général le retrait des formulations mais avec des seuils moindres que ceux de la littérature. Aucun gonflement n’était détecté dans toutes les formulations après les cycles de gel/dégel. Il a été observé une augmentation de la résistance mécanique des formulations optimales contenant 0, 15% et 30% de sédiments et une diminution pour les formulations contenant 50% tout en restant au-dessus des exigences normatives. Pas de carbonatation totale n’est observée à 180 jours de carbonatation accélérée à 3% de CO2 avec une profondeur comprise entre 4,5 et 6 mm. De plus, après carbonatation accélérée, les formulations ont conservé un pH supérieur au seuil de dépassivation des aciers avec des pH plus élevés en carbonatation naturelle. Les produits de carbonatation identifiés sont la nahcolite, et le natron, avec des traces de la calcite dans les formulations contenant des sédiments. Une augmentation de la densité et une amélioration des performances mécaniques a été observée. Nous n’avons pas constaté de gonflement après les attaques sulfatiques externes mais une amélioration des performances mécaniques a été observée. En termes de réaction sulfatique interne, un gonflement léger et négligeable par rapport au seuil de la méthode LCPC no 66 a été observé. Concernant le potentiel de relargage de polluants vers le milieu naturel, la gépolymérisation a été efficace pour l'immobilisation chimique et physique d'un certain nombre d'éléments préoccupants pour l'environnement contenus dans les sources aluminosilicates.Enfin, un modèle thermodynamique, validé par comparaison aux résultats expérimentaux, a permis de prédire la composition des formulations de géopolymères en fonction de différents paramètres.Today, there is a growing interest in sustainable construction, which must be rational and ecological. One of the avenues of innovation and research concerns, the use of alternative materials and the substitution of ordinary cements by other types of binders such as geopolymers. The combination of alternative materials and geopolymer binders will enable us to offer a new generation of low-carbon materials in the future. To meet this need for innovation, the aim of our research work is to recover dredged sediments in a geopolymer binder of the One-Part-Geopolymer type. Through the formulations we have developed, this research makes it possible to replace fly ash with dredged sediments, which are considered to be local materials with a fairly low carbon footprint. In addition, we have simplified the formulation method, using the Just-Add-Water method, which facilitates the use of geopolymers on an industrial scale.In our research work, the percentages of sediment and alkaline activators were optimized in order to select an optimum mortar formulation for each percentage of sediment incorporated as a substitute for fly ash (0, 15, 30 and 50%). Mechanical and physicochemical characterizations showed that sediments improve the mechanical performance and physicochemical properties of geopolymers. The results showed that dredged sediments can be used as a source of aluminosilicates in a geopolymer binder.In order to validate our results, a durability study was carried out on several optimal formulations. These materials showed good performance in terms of volume stability (autogenous shrinkage, drying shrinkage, freezing/thawing), chemical stability (carbonation, external sulphate attack, internal sulphate reaction) and environmental stability (leaching). The evolution of physical phenomena such as shrinkage was linked more to pore distribution than to mass loss. The addition of sediments generally increased the shrinkage of the formulations, but with lower thresholds than those found in the literature. No swelling was detected in all formulations after freeze/thaw cycles. An increase in mechanical strength was observed for optimal formulations containing 0, 15% and 30% sediments, and a decrease for formulations containing 50%, while remaining above the normative requirements. No total carbonation was observed after 180 days of accelerated carbonation at 3% CO2 with a depth of between 4.5 and 6 mm. In addition, after accelerated carbonation, the formulations retained a pH above the depassivation threshold for steels, with higher pH values under natural carbonation. The carbonation products identified were nahcolite and natron, with traces of calcite in the formulations containing sediments. An increase in density and an improvement in mechanical performance was observed. No swelling was observed after external sulphate attack but an improvement in mechanical performance was observed. In terms of internal sulphate reaction, slight and negligible swelling in relation to the threshold of LCPC method No. 66 was observed. With regard to the potential for releasing pollutants into the natural environment, geopolymerization was effective for the chemical and physical immobilization of a number of elements of environmental concern contained in aluminosilicate sources.Finally, a thermodynamic model, validated by comparison with experimental results, was used to predict the composition of geopolymer formulations as a function of various parameters
A Comparison of Parallel and Sequential Niching Methods
No full textNiching methods extend genetic algorithms to domains that require the location of multiple solutions. This study examines and compares four niching methods --- sharing, crowding, sequential niching, and parallel hillclimbing. It focuses on the differences between parallel and sequential niching. The niching methods undergo rigorous testing on optimization and classification problems of increasing difficulty. A niching-based technique is introduced that extends genetic algorithms to classification problems. 1 INTRODUCTION Niching methods (Mahfoud, 1995) promote the formation and maintenance of stable subpopulations in genetic algorithms (GAs), allowing GAs to extend their problem-solving power to complex domains. This study examines four niching methods and compares their performances on problems in both classification and multimodal function optimization. The problems cover a wide range of difficulty levels. Classification problems are solved via a new niching-based technique. Paral..
The impact of the urban structure on the public squares uses: a syntactic analysis
No full textThis work is part of an ongoing research on the impact of urban structure on public squares in Bejaia city (Algeria). This paper will investigate the relationship between the configuration of the urban structure and the use and attractiveness of public squares in Bejaia city. Assuming, from space syntax theory, that urban space configuration extremely effects people’s movement patterns (through-movement space or to-movement space), this study is then carried out to find the correlation between the spatial use of squares and the syntactic properties of the urban structure in which they are embedded. To achieve this goal, the document relies on two approaches: qualitative and quantitative. The qualitative approach is based on the in-situ observation of two public squares by establishing behavioural maps, and on semi-structured interviews. While for the quantitative one, it is based on the method of space syntax concerning the syntactic and isovist properties. The study uses calculations using Depthmap. This paper will present the investigation process and the results of the case study, which show that the use of public squares in Bejaia city depends strongly on the syntactic properties of the urban structure in which each square is embedded, besides its functional properties
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