Mental models for scientific learning are often defined as, "cognitive tools situated between experiments and theories" (Duschl & Grandy, 2012). In learning, these cognitive tools are used to not only take in new information, but to help problem solve in new contexts. Nancy Nersessian (2008) describes a mental model as being [loosely] characterized as a representation of a system with interactive parts with representations of those interactions. Models can be qualitative, quantitative, and/or simulative (mental, physical, computational)" (p. 63). If conceptual parts used by the students in science education are inaccurate, then the resulting model will not be useful. Students in college general chemistry courses are presented with multiple abstract topics and often struggle to fit these parts into complete models. This is especially true for topics that are founded on quantum concepts, such as atomic structure and molecular bonding taught in college general chemistry. The objectives of this study were focused on how students use visual tools introduced during instruction to reason with atomic and molecular structure, what misconceptions may be associated with these visual tools, and how visual modeling skills may be taught to support students' use of visual tools for reasoning. The research questions for this study follow from Gilbert's (2008) theory that experts use multiple representations when reasoning and modeling a system, and Kozma and Russell's (2005) theory of representational competence levels. This study finds that as students developed greater command of their understanding of abstract quantum concepts, they spontaneously provided additional representations to describe their more sophisticated models of atomic and molecular structure during interviews. This suggests that when visual modeling with multiple representations is taught, along with the limitations of the representations, it can assist students in the development of models for reasoning about abstract topics such as atomic and molecular structure. There is further gain if students’ difficulties with these representations are targeted through the use additional instruction such as a workbook that requires the students to exercise their visual modeling skills.

This dissertation examines the substantive representation of ethnoracial minorities at the national level, the inter-minority dynamics of descriptive representation at the state level, and the effects of ethnoracial cues on White public opinion regarding policies that disproportionately affect minorities. Taken together, the three chapters offer evidence to support the claim that race not only shapes mass opinion, but also elites' responses to it. The expectation in a representative democracy is that the preferences of the public should influence the voting behavior of elected officials in Congress. Most scholars agree that this is indeed the case, but they have recently begun to ask whose opinions are most influential. Members of Congress seem to disproportionately represent the interests of copartisans and affluent Americans. The literature speaks less to the nature of the relationship between the political preferences of ethnoracial minorities and the voting behavior of members of Congress. Is there also a racial disparity in representation, even after accounting for partisanship and income? Are White Americans better represented in government decisions than are African Americans and Latinos? Chapter 1 explores the relationship between congressional district-level public opinion on proposed bills (estimated using multilevel regression and poststratification), broken down by racial, partisan, and income group, and the roll call votes of House members on those same bills. I find strong evidence of overresponsiveness by members of Congress to copartisan and high-income constituents, and some evidence of underresponsiveness to Blacks. In some cases, minorities' preferences are underrepresented even by representatives of their own parties, on race-targeted policies, and in majority-minority districts. Chapter 2 examines how legislators respond to coethnic and cominority constituents. I conduct an audit study of all state legislators to explore how they respond to constituents of different ethnoracial groups, and to assess whether Black and Latino state legislators in particular are as responsive to cominority constituents (i.e., non-White individuals from a different ethnic minority group) as they are to coethnics (i.e., individuals from the legislator's own ethnic group). Blacks and Latinos currently make up about one-third of the overall U.S. population, and an even larger share of some state populations. In light of this growing diversification of the American electorate, elected officials have incentives to appeal to a broad racial constituency. I conduct an experiment in which state legislators are randomly assigned to receive an email from a coethnic, cominority, or non-coethnic constituent. My findings suggest that Latino constituents are consistently disadvantaged. White and Republican legislators respond to Latino constituents the least, and Black legislators do not show any cominority solidarity toward them. Latino legislators, on the other hand, do exhibit cominority solidarity toward Black constituents by favoring them over White (non-coethnic) constituents. These results have important implications for the prospect of "black-brown" coalitions and for the descriptive representation of ethnoracial minorities. Finally, understanding the factors that shape White Americans' preferences over policies that disproportionately affect racial and linguistic minorities is increasingly important in a diversifying society. Chapter 3 focuses on the effects of racialized stereotypes on the formation of White public opinion regarding Hurricane Maria relief in Puerto Rico. Due to the ongoing fiscal crisis and the damage caused by the hurricane in 2017, the case of Puerto Rico has figured prominently in American media coverage as of late, but we know little about how the attitudes that shape U.S. policy toward Puerto Rico are formed. I conduct a nationally representative survey experiment in which I have two actors---roughly identical in all features except skin complexion---portray hurricane victims and give general information about the damage Maria caused. By varying the skin tone (light or dark) and language (Spanish or English) in the videos, I am able to assess the ways in which racial and linguistic markers shape Americans' preferences about a putatively race-neutral policy (disaster relief). I find that the Spanish language treatment decreases respondents' support for Puerto Rico, but not by much. The effects of race, on the other hand, are contingent on respondents' partisanship, race, and prior knowledge about Puerto Ricans' American citizenship.

Internet är en plats där alla kan lära sig. Vem som helst kan publicera vilket digitalt läromaterial som helst. För att säkerställa att ett publicerat material är lämpligt är det viktigt att materialet är utformat på ett pedagogiskt sätt. Det är dessutom viktigt att nyttja de fördelar ett digitalt läromedel har som en konventionell bok inte har. Detta arbete undersöker hur Matteboken presenterar tröskelbegrepp i kursen Matematik 1. I arbetet har tröskelbegreppen på Matteboken analyserats med hjälp utav två didaktiska teorier. Den ena är variationsteorin, vilken handlar om att variera aspekter av ett innehåll för att göra uppenbart vad lärandeobjektet är. Den andra är att använda sig av olika representationer, vilket handlar om att representera ett material på olika sätt för att öka förståelsen av lärandeobjektet. Innehållet har även analyserats utifrån det faktum att det är konstruerat för att läsas på en skärm. Arbetets resultat är att det existerar två tröskelbegrepp inom kursen Matematik 1. Dessa två är funktionsbegreppet och bråkbegreppet. Ett centralt resultat i arbetet är att presentationen av dessa tröskelbegrepp på Matteboken kan förbättras med hjälp utav interaktiva moment, variation och olika representationer. / The Internet is a place where everyone can learn and anyone can publish any digital educational material. To make sure that the published material is adequate, it is important that the material is written with pedagogical support. It is also important to utilize the advantages a digital educational material has over conventional educational material. This paper examines and analyses how Matteboken is presenting threshold concepts in the course Matematik 1. This work is done by conducting literature studies and by analyzing Matteboken's presentation of threshold concepts. The analysis is done using two pedagogical theories. One of them is the theory of variation, explaining how varying certain critical features of a critical aspect is a good way to learn. The other one has to do with representations, utilizing different representations of a learning object to increase the understanding of the object of learning. The material at Matteboken has also been analyzed from the fact that the material is supposed to be read on a screen. The result of the paper is that there exists two threshold concepts in Matematik 1. The concept of a function and the concept of a fraction. The result of the paper indicates that Mattebokens’ presentation of the threshold concepts may be improved using interactive tools, variation and different representations.

SpyDrNet is an open-source structural netlist representation framework written in Python that allows users to create, analyze, and manipulate structural netlists. The internal format was designed to hold generic source structural netlists. Verilog and EDIF netlists generated by Vivado were read and written by SpyDrNet. Additional API functionality was built around the netlist representation. An application applying triple modular redundancy and duplication with compare was created and successfully used.

In representation learning we are interested in how data is represented by different models. Representations from different models are often compared by training a new model on a downstream task using the representations and testing their performance. However, this method is not always applicable and it gives limited insight into the representations. In this thesis, we compare natural image representations from classification models and the generative model BigGAN using two other approaches. The first approach compares the geometric clustering of the representations and the second approach compares if the pairwise similarity between images is similar between different models. All models are large pre-trained models trained on ImageNet and the representations are taken as middle layers of the neural networks. A variety of experiments are performed using these approaches. One of the main results of this thesis shows that the representations of different classes are geometrically separated in all models. The experiments also show that there is no significant geometric difference between representations from training data and representations from validation data. Additionally, it was found that the similarity of representations between different models was approximately the same between the classification models AlexNet and ResNet as well as between the classification models and the BigGAN generator. They were also approximately equally similar to each other as they were to the class embedding of the BigGAN generator. Along with the experiment results, this thesis also provide several suggestions for future work in representation learning since a large number of research questions were explored. / Detta verk studerar representationer från artificiella neuronnät. Representationerna tas som värdena på ett lager i mittendelen av neuronnätet. Eftersom dessa representationer har flera olika användningsområden är syftet att jämföra dem från olika modeller. Ofta jämförs representationer genom att testa hur bra de är som input till en ny modell med ett nytt mål; alltså hur bra representationerna är att använda inom “transfer learning”. Denna metod ger begränsad information om representationerna och är inte alltid applicerbar. Detta verk använder därför två andra tillvägagångssätt för att jämföra representationer. Den första är att jämföra geometriska grupperingar hos olika representationer. Den andra använder ett mått av hur lika olika representationer är. Flera olika experiment utförs med hjälp av dessa tillvägagångssätt. Representationerna kommer frånmodeller som redan tränats på ImageNet. Både klassifikationsmodeller och en generativa modell används med syfte att också jämföra dem med varandra. Det första huvudresultatet från experimenten är att det finns en tydlig geometrisk separation av representationer från olika klasser i modellerna. Experimenten visar också att det inte fanns en tydlig geometrisk separation av representationer från träningsdata och valideringsdata. Ett annat resultat är att representationerna från de olika klassifikationsmodellerna AlexNet och ResNet är ungefär lika lika varandra som mellan klassifikationsmodellerna och generatorn hos den generativa modellen BigGAN. Resultaten visar också att de har en liknande likhet till BigGANs “class embedding”. Fler forskningsfrågor undersöks i andra experiment. Utöver experimenten kommer detta verk med många idéer till framtida forskning.

This study investigated the relationship between teachers' pedagogical content knowledge (PCK) about electrostatics and learners' performance in the topic. Two in-service and two pre-service physical science teachers, together with their learners, agreed to participate in the study. The PCK of the teachers was viewed as two manifestations; the personal PCK, which is static in nature and the enacted PCK, which is dynamic. A content representation (CoRe) tool and lesson plans were used to collect data that reflected the personal PCK of the teachers. The data for the enacted PCK was collected using classroom observations, and video stimulated recall (VSR) interviews. A topic specific PCK model was adopted as the framework for this study. The model asserts that specific content is transformed for instruction through five components, namely; learners' prior knowledge, curricular saliency, what is difficult to teach, representations including analogies, and conceptual teaching strategies. Guided by the model, I developed two rubrics to assess and quantify the quality of the teachers' personal and enacted PCK on a four-point scale. Learners, on the other hand, wrote a test developed specifically for this study which explored their performance in the fundamental concepts chosen for this study. The performance of the learners was then related to the personal and the enacted PCK of the teachers separately. The results revealed that the personal and the enacted PCK of the teachers, as well as the performance of the learners, varied across fundamental concepts of electrostatics. The variations in the personal and enacted PCK provided empirical evidence that supports the notion that PCK has a concept specific nature. The results also showed that the performance of the learners was better related to the enacted PCK of the teachers compared to the personal PCK. These results imply that it is important to make teaching practice the centre of pre-service teacher education given the direct impact of enacted PCK on learning. Furthermore, exploring PCK at concept level reveals the strengths and weaknesses of the concepts. As such, pre-service teacher education and in-service teacher professional development may be tailored in a manner that addresses the concepts that require intervention. / Thesis (PhD)--University of Pretoria, 2020. / Science, Mathematics and Technology Education / PhD / Unrestricted

Visual representations are frequently used in teaching as well as in social and science studiesin order to capture and explain complex and abstract phenomena. However, they can bechallenging, complex and difficult to understand. This study, which is carried out within theframework of a research project, aims to investigate how a visual representation can be usedin teaching in order to qualify elementary pupils’ comprehension about democracy, moreclosely by using a flowchart to describe the legislative process. Before this study wasconducted the research group analysed phenomenographically the conceptual understandingof a flowchart of the legislative process of students in the 5th, 8th and 10th grade andidentified the critical aspects of this phenomenon. The method chosen for this study wasorganizing and conducting a lesson based on those identified critical aspects of the flowchartof the legislative process. A pre- and post-test on it were written by the participants whoseresults have been analysed phenomenographically based on the outcome space of thephenomenographic analysis of the research group. The analysis of the pre- and post-testaimed to investigate the pupils’ conceptions of the phenomenon before and after the lessonwhich therefore indicated which of the two critical aspects were discerned during the lesson.Parts of the conducted lesson and discussions between the pupils were analysed, too. Thisanalysis intended to identify elements during the lesson where the critical aspects seemed tobe possible for the pupils to discern. The results of the study showed that although the lessondid not facilitate for the pupils to discern both critical aspects simultaneously, many of themqualified their conception of the phenomenon from before the lesson to after, by havingdiscerned one of the critical aspects. Thus, using visual representations by focusing ondiscerning critical aspects can facilitate a qualified comprehension/conception of complexphenomena.

This thesis explores how children perceive extreme manifestations of social inequalities - poverty and wealth, and what role do media and media representations play in this process. Based on the literature, it is focusing on media construction of reality, media representations, and social inequalities in general, at the same time it deals with poverty and wealth in the context of perception and media representations, and it also explores the relationship between children and media. Furthermore, by analyzing the results of interviews with children the thesis directly examines how they perceive poverty and wealth and what role do media play in this process. The main finding concerning the social inequalities is that most children perceive them as legitimate and to justify them they use the method of naturalization or/and romanticization of poverty. The main finding concerning the media influence is that media affect children subconsciously and that their thoughts and attitudes to poverty and wealth correspond with media representations of the same in the media production for children.

It's known that advanced technologies with their own artificial intelligence (AI) are gaining a bigger part in our daily lives. This AI can be found in phones, in smart homes, and in cars. Furthermore, it can be found in anthropomorphic robots seen in healthcare and in the entertainment industry as two of many examples. These advanced robots have also taken their steps into our friendships, and our romantic and/or sexual lives, in which humans develop parasocial relationships to the robot, creating human-robot relationships. The media has taken a great interest in those relationships, which I’ll call “technosexual relationships”, in which a human is romantically and/or sexually involved with an artificial individual. Oftentimes the artificial individual takes the shape of a so called “sex doll/robot”, which makes the phenomenon of technosexual relationships somewhat controversial to many. Media representations of those relationships are of growing interest, as there’s public curiosity regarding the subject. By also observing how the artificial individual has been framed throughout its history in myths and popular culture in the form of tv-series and films, it becomes obvious that the idea of the artificial individual as a partner and/or lover is viewed as something negative and sometimes even dangerous, a view that has proven difficult to let go off.  In this thesis, by asking three research questions and doing a media content analysis, I’m looking to answer how technosexuality “is being allowed” to exist in and by filmed media - focusing on five previously filmed interviews with technosexual persons and their artificial partner(s). The questions, inspired by Stuart Hall’s representation theory, are as follows: (1) How does the technosexual person speak about themselves?, (2)  How does the media frame the technosexual person and the relationship during the interview?, (3) Does the conversation change from being about artificial sexuality as an individual phenomenon, to whether society's view on relationships and sexuality are going through a reformation?  Results indicate that the technosexual person speaks of themselves as someone who simply prefers a partner that’s predictable and safe, and they usually speak of how they are happier now, in being together with their artificial partner. Furthermore, we can see that the media, to a certain extent, is allowing for the technosexual person and their artificial partner to tell their own story, but that some media producers are trying to manipulate the story being told by editing the story into angled contexts. Finally, we can see that technosexuality is an individual phenomenon that, much by the help of globalized media representation, has begun disrupting and challenges what earlier has been known as “the normal” human sexuality, splitting society into groups of “for” or “against” artificial relationships and their possible part in our understanding of what relationships and sexuality can be.

In the following essay, I focus on the representations of bodily "difference" in the Prague's freakshow culture, particulary on the displays of the so called "Lilliputians", which were popular among the public from the beginning of the 19th Century to the 40's of the 20th Century. Firstly, I introduce the Prague's curiosity exhibitions as a specific social praxis and I compare them with similar displays in Europe and the United States. In the second part of this essay, I try to analyse those exhibitions critically, using the concepts from the present disability studies discourse. I deal with the bodily "otherness" as a category of difference, which arises from the intersection of different ideologies. According to the point of view, this category shaped the individual and collective identities and fostered the social hierarchies of the time. Throughout the essay, I focus on the dis/continuities in the imagination of bodily "difference" and I try to describe the specificity of the Czech freakshow tradition. Key words: 19th Century, body, representations, bodily difference, abnormality, ideology