The ways that physics students’ conceptualize – the way they experience – the use of algebraic signs in vector-kinematics has not been extensively studied. The most comprehensive of these few studies was carried out in South Africa 15 years ago. This study found that the variation in the ways that students experience the use of algebraic signs could be characterized by five qualitatively different categories. The consistency of the nature of this experience across either the same or different educational settings has never given further consideration. This project sets out to do this using two educational settings; one similar to the original South African one, and one at the natural science preparatory programme known as basåret at Uppsala University in Sweden. The study was carried out under the auspices of the Division of Physics Education Research at the Department of Physics and Astronomy at Uppsala University in collaboration with Nadaraj Govender, University of KwaZulu-Natal, who performed the original study while completing his PhD at the University of the Western Cape, South Africa. This study is situated in the kinematics section of introductory physics with participants drawn from the natural science preparatory programme at Uppsala University and physical science preservice teachers’ programme at the University of KwaZulu-Natal, South Africa. The participating students completed a specially designed questionnaire on the use of signs in kinematics problem solving. A sub-group of these students was also purposefully selected to take part in semi-structured interviews that aimed at further exploring their experiences of algebraic signs. The students’ descriptions and answers were categorized using Nadaraj Govender’s set of categories, which had been constructed using the phenomenographic research approach. This approach is designed to enable finding the variation of ways people experience a phenomenon. The process of sorting the data was grounded in this phenomenographic perspective. From this categorization it was possible to identify four of the original five categories amongst the participating students. The results suggest that these four categories remain educationally relevant today even if the context is not the same as the one for the original findings. Although one of the original five categories was not found, the analysis cannot be taken to definitely eliminate this from the original outcome space of results. A more extensive study would be needed for this and thus a proposal is made that further studies be undertaken around this issue. The study ends by suggesting that physics teachers at the introductory level need to obtain a broader understanding of their students’ difficulties and develop their teaching to better deal with the challenges that become more visible in this broader understanding. / På vilka sätt fysikstudenter föreställer sig och förstår användandet av algebraiska tecken i vektorkinematik har endast studerats i mindre utsträckning. Den mest omfattande av dessa få studier genomfördes i Sydafrika för 15 år sedan. Denna studie upptäckte att variationen av de sätt studenter upplever användandet av algebraiska tecken på kunde karaktäriseras genom fem kvalitativt olika kategorier. Hur solida dessa upplevelser är i en liknande eller helt annan utbildningsmiljö har däremot inte studerats vidare. Detta projekt ämnar till att göra detta genom att använda två olika studentgrupper; en liknande den ursprungliga gruppen i Sydafrika, samt det tekniskt-naturvetenskapliga basåret vid Uppsala universitet, Sverige. Studien har genomförts med stöd från avdelningen för fysikens didaktik vid institutionen för fysik och astronomi vid Uppsala universitet i samarbete med Nadaraj Govender, University of KwaZulu-Natal, Sydafrika, som genomförde den ursprungliga studien under sin doktorandutbildning vid University of the Westen Cape, Sydafrika. Denna studie är begränsad till den del av den grundläggande fysiken som behandlar kinematik och innefattade deltagare från det tekniskt-naturvetenskapliga basåret vid Uppsala universitet samt tredje års studenter vid physical science preservice teachers’ programme, University of KwaZulu-Natal, Sydafrika. De deltagande studenterna genomförde ett specialdesignat frågeformulär kring användandet av algebraiska tecken för att lösa kinematiska problem. En del av dessa studenter valdes sedan ut för att delta i semi-strukturerade intervjuer som syftade till att vidare utforska deras upplevelser kring algebraiska tecken. Studenternas beskrivningar och svar kategoriserades med hjälp av Nadaraj Govenders fem kategorier som tagits fram genom ett fenomenografiskt tillvägagångssätt. Detta tillvägagångssätt är framtaget för att kunna hitta variationen av hur människor upplever ett fenomen. Sorteringsprocessen grundades i detta fenomenografiska perspektiv. Från denna kategorisering var det möjligt att identifiera fyra av de fem ursprungliga kategorierna bland de deltagande studenterna. Fyra av de fem ursprungliga kategorierna som föreslagits av Govender återfanns genom denna studie varför dessa kategorier föreslås förbli relevanta idag även om utbildningsmiljön skiljer sig från den ursprungliga. Trots att den femte kategorin inte hittades kan denna inte definitivt exkluderas från det outcome space som beskriver studenters upplevelser för algebraiska tecken. Det föreslås att vidare studier undersöker förekomsten av denna kategori. Studien avslutas med att föreslå att fysik lärare på grundnivå behöver få en bättre förståelse för sina studenters svårigheter samt att de behöver utveckla sin undervisning för att bättre kunna hantera dessa svårigheter och på så sätt göra undervisningen mer anpassad för mångfalden av studenterna.

陸錦儀. / 複本為複印本. / Thesis (M.A.)--香港中文大學硏究院哲學學部. / Fu ben wei fu yin ben. / Includes bibliographical references (leaves 165-169). / Lu Jinyi. / Thesis (M.A.)--Xianggang Zhong wen da xue yan jiu yuan zhe xue xue bu. / 序 --- p.I-V / Chapter [0] --- 前言 --- p.1-16 / 註釋 --- p.17-18 / Chapter [1] --- SIGN/SR－ALabyimtr? --- p.19-30 / 註譯 --- p.31-37 / Chapter [2] --- 符號的反面──所指──概念抑思維？ --- p.38-77 / 註釋 --- p.78-100 / Chapter [3] --- 意義／符號的流動（circulation of sign）：關係的關係 --- p.101-141 / 註釋 --- p.142-146 / Chapter [4] --- 結語 --- p.147-157 / Chapter [5] --- 書目 --- p.158-162

No description available.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Thesis (Ph. D.)--University of Rhode Island, 2005. / Typescript. Includes bibliographical references (leaves 143-146).

The purpose of this paper is to analyze the performance of the Histograms of Oriented Gradients (HOG) as descriptors for traffic signs recognition. The test dataset consists of speed limit traffic signs because of their high inter-class similarities.   HOG features of speed limit signs, which were extracted from different traffic scenes, were computed and a Gentle AdaBoost classifier was invoked to evaluate the different features. The performance of HOG was tested with a dataset consisting of 1727 Swedish speed signs images. Different numbers of HOG features per descriptor, ranging from 36 features up 396 features, were computed for each traffic sign in the benchmark testing. The results show that HOG features perform high classification rate as the Gentle AdaBoost classification rate was 99.42%, and they are suitable to real time traffic sign recognition. However, it is found that changing the number of orientation bins has insignificant effect on the classification rate. In addition to this, HOG descriptors are not robust with respect to sign orientation.

A standardized color code is used to aid the driver in the prompt recognition of highway signs. At night, these signs are illuminated by various light sources including the headlights and other fixed light sources. These light sources may distort the appearance of the colors of the signs at night. The first objective of this study was to provide information about human capabilities with respect to the recognition of different colors under daytime and nighttime lighting. The second objective was to examine the effect of changing the specifications for highway colors from the Federal Highway Administration (FHWA) standards to the American National Standards (ANSI) safety color specifications. A laboratory experiment was conducted in which subjects named the perceived colors of retroreflective signs viewed under daytime and nighttime lighting. Forty subjects from four different age groups representing the driving population participated in the study. Three color samples (red, orange, and yellow) in three different grades (engineering grade, high intensity grade, and diamond grade), and two different color specifications (FHWA and ANSI) were used. Four different fixed light sources (clear mercury, coated mercury, coated metal halide, and high pressure sodium) were used for illuminating the signs. For the nighttime condition, two headlights were used (metal halide and tungsten halogen). Daytime lighting was simulated using a fluorescent D-65 light source. Response times as well as correct responses for naming the colors were collected for each subject. Significant differences were found for nighttime versus daytime viewing of the signing materials. In general, for nighttime viewing, red and orange colors were identified faster than yellow color samples. In most cases, FHWA colors were identified significantly more accurately and faster than the ANSI colors. The coated metal halide headlight performed better than the other fixed light sources. There was no significant difference found between the tungsten halogen and the metal halide headlights. / Graduation date: 1991

In this thesis, the author developed a retroreflective sheeting selection technique for traffic signs. Previous research was used to determine the luminance needed by drivers (demand luminance). The author used roadways scenarios to determine the amount of luminance the retroreflective sheeting on a sign would produce (supply luminance). A spreadsheet was developed to determine the performance of different retroreflective sheeting types by comparing the demand and supply luminance for specific roadway scenarios. Using the results of previous studies, three demand luminance levels were created: replacement, adequate, and desirable. The replacement level represents the level of luminance when a sign needs to be replaced and is 2.5 cd/m2. The adequate level is the recommended amount of luminance when installing new traffic signs and is 10 cd/m2. The desirable level is the approximate level when additional luminance has diminishing returns and is 30 cd/m2. Supply luminance on a specific traffic sign was determined by evaluating roadway geometries, sign placement, retroreflective sheeting type and vehicle data. The author reviewed roadway geometries in Texas to estimate typical number of lanes, shoulder widths and horizontal curvature in the US. Sign placement from the MUTCD determined the typical lateral placements, sign heights, and sign twists. Vehicle data included vehicle dimensions and headlamp type. Both the supply and demand luminance were determined for a specific viewing distance for a given scenario. The viewing distance is the distance a driver needs to read or recognize a sign to respond properly. In addition, the type of sign, alphanumeric or symbol, determined how this distance was calculated. The author developed four sign groups to calculate the distance required to read and respond to a traffic sign, including 1) Stop required, 2) Reduction in speed required, 3) Read the message provided, and 4) Change of lane required. For symbol signs, the minimum required visibility distance (MRVD) was determined for the sign group and for text signs, the viewing distance at a legibility index (LI) of 30 ft/in was found. At these distances, the author calculated the supply luminance and then compared it to the demand luminance levels to determine the performance level. The author developed the Retroreflective Sheeting Selection Spreadsheet (RSSS) to allow others to use the methodology presented in this thesis. RSSS allows users to input the roadway data, vehicle data, and sign data. RSSS takes this information and looks up the supply luminance for the scenario. RSSS then compares the supply luminance to the demand luminance levels and outputs the retroreflective sheeting performance level for the scenario.

Thesis (M.S.)--University of Wyoming, 2008. / Title from PDF title page (viewed on Dec. 23, 2009). Includes bibliographical references (p. 125-126).

Thesis (M.S.)--California Polytechnic State University, 2009. / Mode of access: Internet. Title from PDF title page; viewed on Jan. 7, 2010. Major professor: Helen Yu. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Electrical Engineering." "2009." Includes bibliographical references (p. 82-83).