The Feedback Method. A System Dynamics Approach to Teaching Macroeconomics

This thesis documents a method for improving undergraduate instruction inmacroeconomics. Called the feedback method, it enables students to learn about dynamicbehavior in a market economy by using feedback loop diagrams and interactive computersimulation models instead of static graphs or differential equations. There are at least twotypes of pedagogical problems associated with graphical representation of the economy.First, students seem to have difficulty interpreting static graphs used to illustrate dynamics,which raises questions about the value added by graphs to student understanding. Secondly,the most prominent graph in modern macroeconomics principles textbooks—the aggregatesupply and demand (AS/AD) model—appears to misrepresent disequilibrium conditions inthe economy and cause students who understand the graph to misunderstand importantbehavior in the economy.The feedback method emphasizes dynamics rather than static equilibrium conditions.How the economy changes over time in different contexts is the behavioral question thatstudents repeatedly encounter. The structure of the economy is explained in terms ofreinforcing and counteracting feedback loops. Student understanding of the source ofdynamic economic behavior requires seeking, identifying, and explaining relevant feedbackstructure in an economic system. Interactive computer simulation activities reinforce theinsights gained from studying feedback loops. Even small-scale student participation inmodel-building seems to facilitate understanding of a larger model; moreover, suchparticipation may build respect for the scientific method and an appreciation for theory building by economists. The feedback method is a structural explanation of economic behavior, but it alsoprovides an improved learning structure for students, and the thesis reports on fourexperiments designed to test that claim. Two experiments examined student preferences formethods of learning macroeconomics; for example, using static graphs or a feedback loopdiagram. The experimental designs were quite different, but the results were the same—asignificant majority preferred the feedback method. The most commonly cited reason:feedback loops enable the students to visualize a process in the economy. The third andfourth experiments addressed the performance question. In the third experiment, studentsshowed more understanding of GDP when they had access to a stock-and-flow feedbackdiagram of the economy. In the final experiment, students using feedback loop diagramsdisplayed more understanding of business cycle dynamics than other students who had accessto an AS/AD graph. Teaching students to search for feedback structure in the economy andusing computer simulation to connect structure with behavior appears to be a promisingmethod for teaching macroeconomics

An investigation of an electronic ignition system for internal combustion engines

Many types of electric ignition systems have been developed, used, and discarded in favor of systems less expensive and more adaptable to internal combustion engines, Two types which might be classified as high-tension, jump-spark systems are in common use today. These two systems are (1) Battery-coil ignition used mainly on automobiles, and (2) Magneto-ignition used extensively on aircraft engines. A considerable amount of work has been done to determine the extent to which the character and intensity of the electric spark affect the ignition process. This work has revealed that a certain minimum amount of energy is required from the spark before combustion will occur. Any excess energy over and above that required for combustion appears to have no effect on engine performance. It has also been found that there are many factors which influence the voltage necessary at the spark plug to produce the required spark for combustion. Included in these factors are spark plug electrode temperature, engine speed, engine compression ratio, intake manifold pressure, fuel-air ratio, and amount and nature of lead-compound deposits on the electrodes. The function of the ignition system, therefore, is to provide a spark in the cylinder with sufficient energy to produces combustion under the maximum adverse conditions--Introduction, page 1-2

El temprano comercio de esclavos desde Angola hacia Hispanoamérica y Brasil, 1575-1595

In this essay we use new and overlooked sources to provide a chronology for the early slave trade from Angola to Spanish America, beginning with two voyages that sailed from Luanda Island soon after the arrival of the first governor of Portuguese Angola. Similar voyages to the Caribbean and Río de la Plata were common after 1595, but during the preceding decade, the traffic of enslaved Africans from Angola to Spanish America was largely an extension of an older, more intensive trade from Angola to Brazil.En este ensayo empleamos fuentes nuevas y subutilizadas para ofrecer una cronología del temprano comercio de esclavos desde Angola hacia Hispanoamérica, lo cual comenzó con dos navíos que zarparon de la Isla de Luanda justo después de la llegada del primer gobernador de la Angola portuguesa. Semejantes viajes al Caribe y al Río de la Plata eran comunes a partir de 1595, pero en la década anterior la trata de africanos esclavizados desde Angola hacia Hispanoamérica fue en gran medida una extensión de un tráfico más viejo y más intensivo desde Angola hacia Brasil

QUANTIFYING COORDINATION IN KINEMATIC DATA: A RUNNING EXAMPLE

To compare methods of quantifying coordination, one healthy male participant was filmed in three dimensions at 120 Hz whilst running at 3.8 m/s. The knee and hip angles and angular velocities of the left stride, normalised to 100 data points, were analysed using continuous relative phase (CRP) and cross correlations (CC). The phase planes were normalised to -1 and +1, and the component phase angles (I) for each segment calculated with the range O°<

Capturing the Dynamics of a Psychiatric Illness: A System Dynamics Translation of the Contemporary Biological and Psychological Conceptualization of Panic Disorder (PD)

[email protected] The present study undertakes a partial system dynamics (SD) translation of the contemporary biological and psychological conceptualizations of panic disorder (PD). It makes explicit the dynamic processes implicit in the narrative presentations in the literature. It serves as a facilitator for the discussion about PD for it provides an easy-to-understand and illustrative language for commoners to understand, and researchers of different fields to critically examine, the biological, psychological, social and cognitive aspects of PD

El Atlántico incierto. Transformaciones africanas y europeas de la isla de São Tomé, c. 1533

As the first European colony to specialize in sugar cultivation using a labor force comprised exclusively of enslaved Africans, São Tomé island in the Gulf of Guinea is often considered the birthplace of the sugar plantation complex. But the rise of sugar cultivation there took place amidst deep uncertainties. This essay examines a previously unstudied sixteenth-century São Tomé estate inventory from the vantage points of merchants and officials on São Tomé and in Portugal, and to the extent possible, of the Africans they exploited. Without disputing the economic importance of sugar or that of key sites such as São Tomé for later Atlantic histories, we call attention to contingencies that included the waning fortunes of certain planters and their implications for the enslaved; slave routes’ subordination to changing political dynamics on the African mainland; and evidence of African resistance ranging from litigation to escape to maroon wars that threatened sugar production, the slave trade, and the viability of Portuguese rule on the island. During the 1520s-1530s many parties had a stake in the island’s future, and the rise of sugar was by no means a foreordained outcome.Habiendo sido la primera colonia europea en especializarse en el cultivo de azúcar a base de una mano de obra compuesta por africanos esclavizados, la isla de São Tomé en el Golfo de Guinea se suele considerar la cuna del complejo azucarero-esclavista. Sin embargo, el auge del cultivo de azúcar tuvo lugar en medio de profundas incertidumbres. Este ensayo examina un inventario de haciendas são-tomenses del siglo XVI desde los puntos de vista de comerciantes y oficiales en São Tomé y Portugal y, en la medida que sea posible, de los africanos explotados. Sin cuestionar la importancia económica del azúcar o de puntos claves como São Tomé para historias subsiguientes, señalamos a las contingencias como las fortunas en declive de algunos dueños de plantaciones y sus consecuencias para los esclavizados; la dependencia de las rutas esclavistas de las cambiantes dinámicas políticas en costas africanas; e indicios de resistencia africana, desde la litigación y la fuga hasta las guerras de cimarrones, que perjudicaron la producción azucarera, el tráfico de esclavos y la viabilidad del dominio portugués sobre la isla. En las décadas de 1520 y 1530, muchas partes tenían interés en el futuro de la isla y el auge del azúcar no era predeterminado

Tangomâos en Tenerife y Sierra Leona a mediados del siglo XVI

Siguiendo los pasos de Alexandre Cioranescu, Avelino Teixeira da Mota y Manuel Lobo Cabrera, este ensayo trata de reconstruir aspectos del tráfico de esclavos hacia las islas Canarias que proporcionan nuevas pistas sobre la historia de Sierra Leona a mediados del siglo XVI, justo después de la supuesta invasión de los Manes. Los tangomãos, intermediarios que realmente llevaron a cabo las compras de cautivos africanos, figuran en la historia africana como personajes algo misteriosos. Resulta que algunos residían en Tenerife

Systems Education at Bergen

At the University of Bergen in Norway, educating students to use computer models and to think systemically about social and economic problems began in the 1970s. The International Masters Program in System Dynamics was established in 1995, and a Ph.D. program began a few years later. Student enrolment doubled in 2010 with the establishment of the European Master Program in System Dynamics. International diversity has been a hallmark of the Bergen program; each year, students come from about 30 different countries and more than 95% of the degrees have been awarded to students from outside of Norway. However, a Bergen systems education is not confined to a classroom in Norway. Projects in developing countries, emerging economies, and developed countries have taken the systems perspective and modeling tools on the road and, increasingly, online. Whatever the delivery mode, the goal is the same: capacity building among international students, planners and managers, and local stakeholders. This paper describes the Bergen program and its impact on systems thinking and modeling throughout the world

Systems Education at Bergen

At the University of Bergen in Norway, educating students to use computer models and to think systemically about social and economic problems began in the 1970s. The International Masters Program in System Dynamics was established in 1995, and a Ph.D. program began a few years later. Student enrolment doubled in 2010 with the establishment of the European Master Program in System Dynamics. International diversity has been a hallmark of the Bergen program; each year, students come from about 30 different countries and more than 95% of the degrees have been awarded to students from outside of Norway. However, a Bergen systems education is not confined to a classroom in Norway. Projects in developing countries, emerging economies, and developed countries have taken the systems perspective and modeling tools on the road and, increasingly, online. Whatever the delivery mode, the goal is the same: capacity building among international students, planners and managers, and local stakeholders. This paper describes the Bergen program and its impact on systems thinking and modeling throughout the world.publishedVersio