Notre travail de thèse porte sur les usages du tableau numérique interactif (TNI) en milieu scolaire. Nous étudions plus particulièrement les effets cognitifs des trois potentiels pédagogiques du TNI sur l’enseignement-apprentissage d’une discipline scolaire au cycle III de l’école primaire en France. L’étude est conduite en classes de CM1 et de CM2 et porte sur l’enseignement-apprentissage de la notion de fraction. La relation entre l’utilisation du TNI et les effets de ces usages sur l’apprentissage des élèves apparait complexe et soulève beaucoup de questions. Cette complexité provient avant tout de la pluralité des facteurs participant plus ou moins au processus d’enseignement et d’apprentissage. Pour mieux appréhender cette problématique, notre recherche s’est centrée sur l’influence des trois thématiques du TNI : 1. L’interactivité technico-pédagogique supportée par l’usage du TNI ; 2. Les modalités et l’ergonomie de travail impliqué par l’usage du TNI ; 3. Les supports multimodaux visuels et manipulables utilisé sur cet instrument numérique.Cette étude s’appuie sur des éléments théoriques mis en oeuvre dans les recherches dans les domaines de la pédagogie et des didactiques disciplinaires permettant de traiter cette problématique. Nous avons porté notre réflexion, dans un premier temps, sur la notion de médiation en nous appuyant sur l’approche instrumentale selon Rabardel (1995). Les tâches réalisées en classe se font dans un cadre collectif. Nous les analysons, dans un deuxième temps, selon la théorie de l’activité d’Engeström (1987). Nous nous inspirons, enfin, des travaux de Piaget (1948) afin de comprendre le développement et la construction de la notion de fraction chez l’enfant. En outre, dans cette recherche, le TNI n’est pas un instrument isolé des autres éléments existant en classe mais il est un dispositif techno-sémio-pragmatique (Peraya, 1999). De ce point de vue, le TNI réunit trois entités : la technique, la sémiotique et le social. Le TNI est donc vu comme l’ensemble des interactions entre ces trois domaines : technologique, technosocial et système de représentations de l’ordre du sémiocognitif. Les trois champs d’investigation du TNI ont été menés auprès d’un échantillon composé d’élèves et d’enseignants du département du Rhône et Lyon intra-muros à travers des questionnaires, des observations directes sur le terrain, des entretiens et des pré et post tests. L’objectif de pluralité des outils de construction des données était de confronter les avis obtenus afin de s’interroger sur les effets des trois potentiels pédagogiques du TNI sur l’enseignement et l’apprentissage de la notion de fraction.Cette recherche montre que le TNI est un instrument très utile pour l’enseignement-apprentissage des fractions. En particulier, nous avons constaté que le TNI favorise les interactions entre les différents acteurs dans la classe et la construction collective des connaissances. Les enseignants ont insisté particulièrement sur l’aide que le TNI apportait au développement relationnel des élèves et facilitait singulièrement la conceptualisation de la notion de fraction. Les supports multimodaux visuels et manipulables du TNI constituent également une aide cognitive pour les élèves dans leur apprentissage. / Our work deals with the use of interactive whiteboard (IWB) in schools. We are particularly interested in the cognitive effects of three pedagogical potentials of the IWB on the teaching and learning in Cycle III of primary school in France. The study is conducted in primary classes 4 (CM1) and primary 5 (CM2) and focuses on the teaching and learning of the concept of fractions.The relationship between the use of IWB and the effects of these practices on student learning appears complex and raises many questions. This complexity comes primarily from the plurality of factors more or less involved in the teaching and learning process. To better understand this issue, our research focuses on the influence of the three themes of the IWB: 1. the technical educational interactivity supported by the use of IWB; 2. the terms and working ergonomics involved by the use of IWB; 3. Visual and manipulated multimodal media used on this digital instrument.This study focuses on theoretical elements used in research in the fields of education and disciplinary teaching to address this problem. We based our thinking, initially, on the notion of mediation by drawing on the instrumental approach according to Rabardel (1995). The tasks done in the classroom are in a collective framework. Secondly, we analyze, according to the theory of activity of Engeström (1987). Finally, we are inspired by the works of Piaget (1948) in order to understand the development and construction of the notion of fractions in children. Besides, in this research, the IWB is not isolated from other existing elements in the class but it is a techno-semiotic-pragmatic device (Peraya, 1999). From this point of view, the IWB meets three entities: the technic, the semiotics and the social. The IWB is seen as the set of interactions between these three areas: technological, technosocial and system of representations of the order of semiocognitif.The three fields of investigation of the IWB were conducted with a sample composed of students and teachers from the department of Rhone through questionnaires, direct field observations, interviews and pre and post testing. The objective of plurality of data construction tools was to confront the opinions obtained in order to consider the effects of three pedagogical potentials of the IWB on the teaching and learning of the concept of fractions.This research shows that IWB is a very useful tool for the teaching and learning of fractions. In particular, we found that the IWB promotes interactions between different actors in the classroom and the collective construction of knowledge. Teachers have particularlyemphasized the assistance the IWB has brought to the relational development of students and the singular facilitation the conceptualization of the concept of fractions. Visual and multimodal media manipulation of the IWB is also a cognitive aid for students in their learning.

Thesis (M. Ed. (Curriculum Studies)) -- University of Limpopo, 2021 / The purpose of the research was to explore challenges encountered by teachers when teaching fractions to learners in grade 2 at schools in the Koloti Circuit. A qualitative approach including other research techniques, such as observation, document analysis and interviews, were mutually employed to collect data during the study. A pluralistic approach was employed when gathering data to enhance triangulation and further intensify the merits of the probed facts. Purposive sampling was employed to choose three grade 2 teachers from various schools to serve as participants in this study. The following challenges were uncovered as a result of the research: learners are from child-headed families; there is a high rate of learner absenteeism; parents do not attend consultative meetings; there is a high rate of teacher time-offs; there is a lack of teacher pedagogical content knowledge in mathematics; teachers have to teach in multi-grade classroom; teachers lacking background knowledge on implementation of inclusive classrooms resulting in inadequate support to learners with learning barriers; classrooms are over-crowded; uneven partitioning of circular representations was discovered, and there is lack of content-related workshops. The following were some of the recommendations that were established to counteract the challenges uncovered during the research study, namely: establishment of after-care centres with qualified tutors; provision of state paid security services in schools; teachers should create learner support materials to aid in the teaching of fractions to the learners; teachers should notify parents when their children are absenting themselves from school on regular basis without valid reasons; teachers should notify parents about the benefits of attending consultative meetings; memorial services for teachers should be conducted after learner contact time, competent and/or qualified teachers in arithmetic should be assigned to educate the subject; small schools should be merged to curb multi-grate teaching at schools; more classrooms should be provided to avoid over-crowding in the classrooms, and more content workshops should be organised in order to assist teachers who experience challenges with the teaching of fractions. In conclusion, the outcomes of this study could aid grade 2 teachers in instilling knowledge of fractions into their learners, crafted on the suggested recommendations that are drawn subsequent the challenges facing teachers were singled out, in order to improve learner performance in fractions. This could result in better performance by learners in mathematics at various schools.

No description available.

Thesis (MEd)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Research shows that misconceptions about calculations develop in many classrooms without being noticed and these are not corrected by repeated routine exercises. The misconceptions formed are at times the result of inappropriate models used to solve problems. An even bigger concern is that these particular models sometimes provide the correct answers by accident. This may result in the learner's belief in the models being reinforced, as described by Swan (n.d.). The aim of this study is to identify the misconceptions related to the use of decimal fractions by Grade 8 and 9 learners and then, through the use of an intervention program, to address the learners' misconceptions and attempt to correct them. Two schools were involved in this study. The group of learners from school A served as a control group to determine the success of the intervention in learners from school B. The results of school A, the frequency and nature of errors were compared with the test results of school B as well as described by interviews with learners from school B. After the diagnostic tests and interview, the learners' answers were compared with those already described in literature. The learners from school B participated voluntarily in the intervention program. Learners from both schools wrote a post-test and the results were compared with those of a pre-test. The conclusion of this study is that there are misconceptions concerning calculations with decimal fractions at Grade 8 and 9 level. These misconceptions are formed during the intermediate phase and are not suitably corrected. The intervention program, for various reasons, had limited success. These reasons are discussed and recommendations are made for future intervention programs. / AFRIKAANSE OPSOMMING: Navorsing toon dat wanbegrippe ten opsigte van berekeninge in baie klaskamers onopgemerk verbygaan en dat dit nie reggestel word deur herhaalde roetine oefeninge nie. Wanbegrippe wat kinders vorm is onder andere die gevolg van onvanpaste modelle wat gebruik word vir die oplos van probleme. 'n Groter gevaar is dat hierdie onvanpaste modelle toevallig die regte antwoord lewer. Dit kan dan veroorsaak dat die leerder se vertroue op die modelle net versterk word, soos Swan (s.j.) dit beskryf. Die doel van hierdie studie is om wanbegrippe ten opsigte van bewerkings met desimale breuke by Graad 8 en 9 leerders te identifiseer en dan deur middel van 'n intervensieprogram die leerders se wanbegrippe aan te spreek en te probeer regstel. Twee skole is by hierdie studie betrek. Die groep leerders van skool A sou dien as 'n kontrolegroep om die intervensie-sukses van die leerders van skool B te bepaal. Die skool A resultate en frekwensie van foute asook die aard daarvan is vergelyk met die toetse van skool B en beskryf op grond van onderhoude met die leerders van skool B. Ná die diagnostiese toets en onderhoud is die leerders se antwoorde vergelyk met dié wat reeds in die literatuur beskryf is. Die leerders van skool B is op vrywillige basis by 'n intervensieprogram betrek. Beide skole se leerders het daarna 'n natoets geskryf en die resultate is vergelyk met dié van die voortoets. Die gevolgtrekking wat uit hierdie studie gemaak word, is dat daar wanbegrippe ten opsigte van bewerkings met desimale breuke op graad 8 en 9 vlak aanwesig is. Hierdie wanbegrippe is in die intermediêre fase gevorm en nie reggestel nie. Die intervensieprogram het om verskeie redes slegs beperkte sukses gehad. Hierdie redes word bespreek en aanbevelings word gemaak vir toekomstige intervensieprogramme.

Στην εργασία αυτή παρουσιάζονται τα βασικά στοιχεία της θεωρίας των συνεχιζόμενων κλασμάτων και στη συνέχεια αναπτύσσονται οι αλγόριθμοι που επιτρέπουν την εκτέλεση πράξεων μεταξύ συνεχιζόμενων κλασμάτων και ρητών αριθμώ,αλλά και μεταξύ συνεχιζόμενων κλασμάτων. / In this thesis we describe the basic theory of continued fractions and describe the algorithms that enable us to perform arithmetic operations with continued fractions and rational numbers,as well as with continued fractions.

Water, sediments, floodplain soils, and fish from Big and Little Bayou creeks were assessed for polychlorinated biphenyls (PCBs) and metals in 1987-2005. The streams were impacted by effluents from the Paducah Gaseous Diffusion Plant (PGDP). PCBs were rarely detected in water samples. Aroclor 1248 detections in sediments and floodplains were sporadic, but 1254 and 1260 were consistent. Seasonal variations were only observed for Aroclor 1248. Detection of PCBs in floodplains indicated recent influx of contaminated sediments. Species-specific PCB residues patterns were studied for Lepomis cyanellus, L. megalotis, L. macrochirus, and Campostoma anomalum. Highest PCB concentrations were found in stoneroller minnows. PCBs decreased over time in sunfish species, but retained a baseline level. No relationships were found between sunfish age and PCB concentrations. At low PCB levels, green sunfish body burden (BB) did not correlate with lipid content. A certain PCB concentration must be exceeded before PCB BB correlates with lipid content. Stream flows differed by season, and fish PCB BB differed by season, but stream flow did not correlate with fish BB. Congener groups corresponded to Aroclor concentrations. Higher chlorinated biphenyls peaked in the spring for sport fish. PCBs remobilized in the spring resulted in higher summer BB for the stoneroller minnows, whereas sunfish eliminated PCBs by summer. This variability was due to the sunfishs ability to regulate PCBs. Metal concentrations did not display the seasonal variability evident in the PCB data. Water metals may have peaked during storm events and decreased rapidly. Water Pb increased with time, but the source could not determined. Zinc in Little Bayou creek likely originated from the PGDP. Except for Cu and Zn, stoneroller minnow metal BB decreased with time. Metal BB were used to determine bioavailable fractions. Less than half of the water column Cd, Cr, Fe, and Pb in impacted areas were bioavailable to stoneroller minnows, whereas 59% of Ag, 73% of Cu, and 64% of Zn were bioavailable. Cumulative criterion units were calculated to determine additive metal impacts, and proved useful in locating sectors with possible ecological impact. In-situ monitors proved valuable in studying PCB and metal behavior under real-world conditions.

<p>This thesis work was made for Södra Cell Mörrums bruk in Blekinge. The purpose of the work was to develop a computer model in the simulation program Extend for the removal and balance of organic oxygen consuming substances, measured as COD (Chemical Oxygen Demand), in the new biological treatment plant in the mill. The plant produces two different pulp products, TCF- (Totally Chlorine Free) pulp and ECF- (Elementary Chlorine Free) pulp, for sale. The different bleaching procedures affect the characteristic of the wastewater and thus the effectiveness of the biological treatment plant.</p><p>In the model that was developed the COD in the wastewater was divided into five different COD-fractions: soluble easily degradable (SS), soluble hardly degradable (SR), soluble inert (SI), particulate inert (XI) and particulate biomass (XB). To create the model FlowMac™ was used as a base. FlowMac™ is a library module in Extend adapted for pulp and paper mills. Some of the blocks only needed a slight modification while others, for example the sedimentation basin and the bioblocks, had to be done from scratch. The calibration of the model was made from data from a period of eleven weeks and a validation was made from data that differed as much as possible from the calibration data. Then the model was used to find out in what way an increase in production to 480 000 annual tons should affect the discharge of organic oxygen consumption substances.</p><p>Results from the model indicates that the goals for the total COD-discharge will be hard to achieve with an increase in production to 480 000 annual tons. Despite the fact that production of TCF-pulp generates more COD than ECF-production the total discharge of COD is lower at TCF-production. The reason is that easier degradable COD is generated in TCF-bleaching. One of the major problems is that the torrent of water that is bypassed the biological treatment plant contains a large amount of COD and the efficiency of the treatment plant must be very high if the goals for the total COD-discharge shouldn’t be exceeded.</p> / <p>Det här examensarbetet gjordes för Södra Cell på Mörrums Bruk i Blekinge. Arbetet bestod i att göra en modell i simuleringsprogrammet Extend över nedbrytningen och massbalansen av organiska syreförbrukande ämnen, mätt som COD (Chemical Oxygen Demand), i den nybyggda biologiska reningsanläggningen på bruket. Mörrums bruk är en sulfatmassafabrik som producerar både TCF- (Totally Chlorine Free) och ECF- (Elementary Chlorine Free) massa för avsalu. De olika blekningsmetoderna påverkar sammansättningen på avloppsvattnet och därmed också den biologiska reningsanläggningens reduktion av COD.</p><p>I modellen som utvecklades delades inkommande COD i obehandlat vatten upp i fem olika COD-fraktioner: löst lättnedbrytbart (SS), löst svårnedbrytbart (SR), löst inert (SI), partikulärt inert (XI) och partikulärt nedbrytbart COD i form av biomassa (XB). För att bygga modellen användes FlowMac™ som utgångspunkt. FlowMac™ är en biblioteksmodul i Extend avpassad för pappersbruk. En del block behövde bara modifieras medan andra block, t.ex. sedimenteringen och bioblocken, fick byggas till. Modellen kalibrerades med medelvärden från en elvaveckorsperiod och en validering gjordes med data från några veckor med mer extrema värden på inkommande vatten. Med modellen gjordes en simulering för att undersöka vad en produktionsökning till 480 000 årston skulle innebära med avseende på utsläppen av organiska syreförbrukande ämnen.</p><p>Resultat från modellen tyder på att det vid en ökning av produktionen till 480 000 årston blir svårt att nå de uppställda totala utsläppsmålen för COD. Vid produktion av TCF-massa bildas mer COD men utsläppsmängderna är lägre än vid ECF-produktion. Anledningen är att den COD som bildas ut vid TCF-blekning innehåller en större mängd lättnedbrytbart COD. En bidragande orsak till att det blir svårt att hålla utsläppsmålen för COD är att de flöden som leds förbi reningsanläggningen innehåller mycket COD vilket gör att verkningsgraden över reningsanläggningen måste vara hög för att klara målen för totala COD-utsläppet.</p>

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Les objets étudiés dans cette thèse sont des algorithmes de calcul de pgcd. Nous effectuons dans cette thèse des analyses probabilistes de plusieurs de ces algorithmes : les algorithmes alpha-euclidiens, l'algorithme LSB et l'algorithme de Lehmer-Euclide. Nous obtenons des résultats précis sur le comportement moyen de toute une gamme de paramètres, entre autres le nombre d'itérations et la complexité en bits. Les techniques employées sont celles de l'analyse dynamique d'algorithmes, et les analyses effectuées dans cette thèse permettent d'élargir le champ d'application de cette méthodologie. En particulier, nous étudions des systèmes dynamiques à branches non surjectives, des systèmes dynamiques définis sur l'ensemble des nombres p-adiques ou encore des systèmes de fonctions itérées. Ces analyses impliquent une étude très précise des opérateurs de Perron-Frobenius et des opérateurs de transfert associés à ces systèmes. En particulier, le comportement probabiliste des algorithmes est relié aux propriétés spectrales de ces opérateurs. Nous analysons également l'évolution des principaux paramètres des algorithmes au cours de leur execution.

Tirtas kukurūzų frakcijų kiekio pasiskirstymo priklausomybė nuo atstumų dydžio tarp trupintuvo valcų. Tyrimai atlikti 2013-2014 metais Aleksandro Stulginskio universitete. Tyrimo objektas – diskinių valcų trupintuvas-traiškytuvas, kurio našumas iki 15 t.h-1. Valcai – apvalūs, dantyti, sukimosi dažnis ns = 4000 min-1. Trupintuvą-traiškytuvą sudaro keturi valcai, dvi poros – pakopos. Trupintuvo diskiniams valcams sukti, reikalinga aktyvioji galia, matuota elektros energijos tinklo analizavimo prietaisu ME-MI2492 („Metrel“). Frakcijų atskyrimui buvo naudojami penki sietai: 3,5 mm; 3 mm; 2,4 mm; 2 mm; 1 mm. Iš viso gautos šešios frakcijos. Valcų atstumas kito nuo 4,5 iki 6 mm pirmos pakopos ir nuo 1,5 iki 3 mm antrosios pakopos. Tyrimais nustatytas žymus, frakcijų didesnių nei 3,5 mm, kiekio didėjimas. Grūdų drėgniui sumažėjus pastebėtas galios poreikio padidėjimas esant minimaliems atstumams tarp valcų. Apdorojus duomenis nustatytas esminis skirtumas tarp frakcijų didesnių nei 3,5 mm kiekio procentinės dalies, esant santykiniam grūdų drėgniui ωg1=37,77±0,5% ir frakcijų kiekio kai drėgnis ωg3=33,25±0,88%. / Studied corn fraction pattern on the cracker rolls gap wide. Investigations were carried out in 2013-2014 at Aleksandras Stulginskis University. Research object was a disc roller crusher, with a capacity of up to 15 t.h-1. Rollers - rounded, toothed, rotation speed n = 4000 min -1. Crusher consists of four rolls, two pairs in all. Crusher disc rolls turn required active power, measured electricity network analysis device ME- MI2492 ( Metrel ) sievs was used in five screens: 3.5 mm; 3 mm; 2.4 mm; 2 mm; 1 mm. A total of six groups. The results demonstrated significant groups larger than 3.5 mm, the increase in volume. Grain moisture decreased observed a increase in power consumption at the minimum roller distance. After processing the data a fundamental difference been set between the groups of larger than 3,5 mm the percentage of grain moisture ωg1 = 37.77 ± 0.5% and the volume fraction when humidity ωg3 = 33.25 ± 0.88 %.