Research into the usefulness of scientific diagrams as teaching and learning tools has revealed their great effectiveness in reinforcing and replacing text; summarizing, clarifying, grouping and comparing information; illustrating abstract concepts and spatial relations between concepts; and aiding understanding and integration of knowledge. However, these advantages are not always realised as diagram effectiveness depends on the student's cognitive ability, visual literacy and prior knowledge. In biochemistry, flow diagrams are used as tools for the visualisation of biochemical processes, the abstract nature of which presents problems to students, probably because the depicted content is beyond their perceptual experience. In this study, we define visualisation as the entire process from the perception of an external representation (e.g. diagram), its internal processing, and the expression of a mental model of the represented content. Therefore, visualisation incorporates reasoning processes and interactions with a student's conceptual knowledge, in their construction of a mental model. Students' visualisation difficulties, in terms of conceptual and reasoning difficulties, have been well researched in areas such as physics and chemistry, but neglected in biochemistry, especially with respect to the use of diagrams as visualisation tools. Thus the aim of this study was to investigate students' use of diagrams for the visualisation of biochemical processes, and to identify the nature, and potential sources of students' conceptual, reasoning and diagram-related difficulties revealed during the visualisation process. The study groups ranged from 27 to 95 biochemistry students from the University of Natal and 2 to 13 local and international experts. Propositional knowledge was obtained from textbooks and from a questionnaire to experts. Data on student visualisation of biochemical processes was obtained from their responses to written and interview probes as well as student-generated diagrams. All data was subjected to inductive analysis according to McMillan and Schumacher (1993) and any difficulties that emerged were classified at levels 1- 3 on the framework of Grayson et al. (2001). The possible sources of difficulties were considered in terms of a model by Schonborn et al. (2003 & 2002). The results revealed the following major findings. The meaning of linear, cyclic and cascade biochemical processes was partially resolved by means of an extensive list of generic and distinguishing functional features obtained from experts. Attempts to clarify propositional knowledge of the complement system revealed a deficiency in our understanding of the functional relationship between the complement pathways and highlighted the need for further experimental laboratory work. Several students literally interpreted diagrams of the functional characteristics of biochemical processes (e.g. cyclic) as the spatial arrangement of the intermediates within cells (e.g. occur in "circles"), although in some cases, their verbal responses revealed that they did not hold this difficulty suggesting that they might hold more than one internal model of the process. Some students also showed difficulty using textbook diagrams to visualise the chemistry of glycolytic and complement reactions. In this regard, besides students' conceptual knowledge and reasoning ability, a major source of these difficulties included misleading symbolism and visiospatial characteristics in the diagrams, suggesting the need for improvement of diagram design through the use of clearer symbolism, the standardization of conventions, and improvement of visiospatial properties of diagrams. The results constituted further empirical evidence for the model of Schonbom et al. (2003 & 2002) and led to the proposal of a model of visualisation aimed at clarifying the highly complex and cognitive processes involved in individuals' visualisation of biochemical processes in living systems. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.

Call number: LD2668 .T4 1950 W4 / Master of Science

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Thesis (M. S.)--Psychology, Georgia Institute of Technology, 2009. / Committee Chair: Rogers, Wendy; Committee Member: Fisk, Arthur; Committee Member: Walker, Bruce

Thesis (M.S. in Engineering Science)--Naval Postgraduate School, December 1990. / Thesis Advisor: Lum, Vincent Y. Second Reader: Wu, Thamas C. "December 1990." Description based on title screen as viewed on March 30, 2010. DTIC Identifier(s): Data base management systems, data management, multimedia data bases, data bases, data processing, tables(data), computer files, MDBMS (multimedia data base management system), Ingres data bases, abstract data types, catalog management, integrated systems, theses. Author(s) subject terms: Multimedia Database Management System, Multimedia, DBMS, MDBMS, media database. Includes bibliographical references (p. 186-187). Also available in print.

This study is concerned with how children interpret the slope of a line graph. Today with the vast accumulations of data which are available from computers, people are being faced with an ever increasing amount of pictorial representation of this data. Therefore it is of the utmost importance that children understand pictorial representation. Yet in spite of the popularity of graphs as tools of communication, studies show that many adults experience difficulty in reading information presented in a graphical form. The slope of the graph was chosen for this investigation because it is in this aspect of graphing (as shown by the results of the 1981 B.C. Assessment) that children in British Columbia seem to have the greatest difficulty when they reach Grade 8. The study dealt with positive, negative, zero and infinite slopes, combinations of these slopes, curvilinear graphs and qualitative graphs, that is, graphs that have no numerical data shown on the axes. The researcher chose to use a structured individual interview as a means of collecting data about how the students interpreted the slope of a line graph. Graphs used in the interviews dealt with temperature, height, weight and distance. Twenty-two students were chosen for this study. The students were found to have problems mainly with graphs dealing with distance related to time. This problem may be due to the fact that many students read only one axis and when interpreting distance seem to include direction as an added dimension of the graph. Infinite slope graphs were misinterpreted by every student, which may be due to the fact that they ignore the time axis. In general students used two methods of interpreting graphs. In some cases they observed the direction of the graph from left to right, that is, whether the slope went up or down from left to right. In other cases they examined the end points on the graph and drew their conclusions from them. The choice of method varied with the contextual material shown on the graph, which may be due to the children's concept of the parameter in the physical world and whether they see the parameter as being able to increase and decrease over time. From the study the investigator feels that more discussion of graphing by teachers and students is needed if the misconceptions are to be cleared up. Discussion of the parameters of both axes by teachers might help clear up the misconceptions students have about distance travelled over a period of time when this is expressed as a graph. There would be less chance of a graph being read as a map if the relationships between the two axes were demonstrated to students. Teachers also need to be aware of both methods used by students in interpreting graphs. / Education, Faculty of / Graduate

In statistical process control, it is usually assumed that observations on the process output at different times are lID. However, for many processes the observations are correlated and control charts for monitoring these processes have recently received much attention. For monitoring the process level, this study evaluates the properties of control charts, such as the EWMA chart and the CUSUM chart, based on the residuals from the forecast values of an ARMA model. It is assumed that the process mean is a ftrst order autoregressive (AR(l)) model and the observations are the mean plus a random error. Properties of these charts are evaluated using a Markov chain approach or an integral equation approach. The performance of control charts based on the residuals is compared to the performance of control charts based on the original observations. A combined chart using forecasts and residuals as the control statistics as well as a combined chart using the EWMA of observations and the EWMA of residuals as the control statistics are also studied by simulation. It is found that no universally "good" chart exists among all the charts investigated in this study. In addition, for monitoring the process variance, two kinds of EWMA chart based on residuals are studied and compared. / Ph. D.

A control chart that simultaneously tracks the mean and variance of a normally distributed variable with no compensation effect is defined in this work. This joint control chart is compared to five other charts: an Χ chart, an s² chart, a Reynolds and Ghosh chart, a Repko process capability plot, and a t-statistic chart. The criterion for comparison is the probability of a Type II sampling error. Several out-of-control cases are examined. In the case of Repko, an equation is defined to compute the Type II error probability. The results indicate that the Reynolds and Ghosh statistic is powerful for cases when the variance shifts out of control. The Χ chart is powerful when the mean shifts with moderate changes in the variance. The joint chart is powerful for moderate changes in the mean and variance. / Master of Science