Computation of Smooth Optical Flow in a Feedback Connected Analog Network

In 1986, Tanner and Mead \cite{Tanner_Mead86} implemented an interesting constraint satisfaction circuit for global motion sensing in aVLSI. We report here a new and improved aVLSI implementation that provides smooth optical flow as well as global motion in a two dimensional visual field. The computation of optical flow is an ill-posed problem, which expresses itself as the aperture problem. However, the optical flow can be estimated by the use of regularization methods, in which additional constraints are introduced in terms of a global energy functional that must be minimized. We show how the algorithmic constraints of Horn and Schunck \cite{Horn_Schunck81} on computing smooth optical flow can be mapped onto the physical constraints of an equivalent electronic network

Touch Typing Tutor for visually impaired children and young people

Touch Typing Tutor is a software programme which was designed to assist teaching touch typing skills to visually impaired children. It was first designed and written in the 1990s by Graeme Douglas and Alan Gamble and then updated in 2000 and is now available as freeware. The programme was specially designed to meet the needs of visually impaired people (in particular children and young people). For example, it provides the means to set up different colours, dimensions and fonts for the exercise text displayed, and has speech capability. These features make it possible for Touch Typing Tutor to be operated independently by the learner. This program is easy to use, with a full set of touch typing exercises supplied. Additional exercises can easily be created using any text editor which is capable of writing plain ASCII files (e.g. the Windows 'Notepad'), and organised into lessons. This means that you are able to use Touch Typing Tutor to teach according to the scheme of your choice - no particular approach is built into the program itself - even replacing the entire suite of lessons with your own if you wish. The software has been used extensively in the UK as well as other parts of the world (particularly Africa)

Antony van Leeuwenhoek: Creation “Magnified” Through His Magnificent Microscopes

Although van Leeuwenhoek was not the inventor of the microscope, he advanced it more than anyone else for seeing living things. Antony van Leeuwenhoek1 (Fig. 1) found great joy in God’s smallest creatures. He first discovered protozoans in his youth. The Dutch haberdasher retained a child-like joy of discovery from his youth until his death at age 90. He lived to see tiny microbes though his homemade microscopes. He loved to grind and focus a new lens in order to see the unseen world. Leeuwenhoek spent countless hours grinding tiny lenses and looking through them. This Christian lay biologist even used candlelight to see specimens at night. For Leeuwenhoek, the amazing diversity of tiny life forms revealed under his homemade microscopes glorified God as much as looking at stars through a telescope. Leeuwenhoek was born in South Holland in 1632. As a young adult, he became a cloth merchant (also called a draper, or haberdasher). In 1668, he started his biological study as a hobby after seeing beautiful microscopic pictures while making a visit to London. After years of careful study, Leeuwenhoek (Fig. 2) made the microscope famous. In his lifetime, he became the father of microbiology and opened mankind to the world of microorganisms

Robert Koch, Creation, and the Specificity of Germs

Microbiology is dominated by evolution today. Just look at any text, journal article, or the topics presented at professional scientific meetings. Darwin is dominant. Microbiology is dominated by evolution today. Just look at any text, journal article, or the topics presented at professional scientific meetings. Darwin is dominant. Many argue that “nothing in biology makes sense except in the light of evolution” (Dobzhansky 1973). But it was not always this way. In fact, a review of the major founders of microbiology has shown that they were creationists.1 We would argue that a better idea thanevolution and one of much more practical importance is the germ theory of disease, originally put forth primarily by non-Darwinian biologists (Gillen and Oliver 2009). In our previous article (Gillen and Oliver 2009), we documented these and many other creation and Christian contributions to germ theory. But only recently has it become known that another important microbiology founder, Robert Koch (Fig. 1) and his co-workers were Linnaean creationists in their classification.2 This is due, in part, to additional works of Robert Koch that were translated from German to English. The year 2010 marks the 100thanniversary of his death (died: May 27, 1910). Although Koch and other German microbiologists were fairly secular in their thinking, their acceptance of Darwinian evolution was minimal

"Public Infrastructure Investment: A Bridge to Productivity Growth? Public Capital and Economic Growth, ; New Federal Spending for Infrastructure: Should We Let This Genie Out of the Bottle?

This brief presents contrasting views on the effects of public infrastructure investment on private sector productivity. Aschauer states that the slower rate of productivity growth since the early 1970s--coupled with an aging population, the declining proportion of workers to the total population, and other demographic factors--poses a dilemma for policymakers interested in strengthening the long-term relative position of the United States in an increasingly competitive global economic environment. He considers public infrastructure to be a factor in production and the decline in public capital to be responsible for part of the productivity slowdown. In contrast, Holtz-Eakin dismisses the conventional arguments for a federal infrastructure program by asserting that a large-scale public infrastructure program has no appreciable effect on productivity growth; in the current fiscal climate of scarce federal resources, a federal infrastructure program is not consistent with the goal of deficit reduction; there are better infrastructure strategies than new spending and massive construction programs; and policies aimed at increasing private rather than public investment will have a more positive impact on U.S. competitiveness.

Inventory Fluctuations in the United States Since 1929

It has been known for a long time that inventory fluctuations are of great importance in business cycles. But inventory fluctuations are fundamentally a short-period phenomenon. Consequently, annual data may shed relatively little light on the nature of inventory fluctuations; most of the "action" may be played out within the year. For this reason, economists know precious little about inventory behavior before World War II. This paper seeks to lift this veil of ignorance in two ways. First,we create -- from some admittedly incomplete and imperfect data -- monthly time series on inventory holdings in manufacturing, durable manufacturing,and nondurable manufacturing. To our knowledge, these are the first such series ever made available.(The data are available on request.) Second,we apply to the prewar data certain statistical procedures and models that are in common use with postwar data. In this way, we can address the central issue of the paper: Has inventory behavior changed? While we do not wish to overstate the case, we were struck more by the similarities in inventory behavior between the prewar and postwar periods than by the differences. But the relevant stylized facts and regressing are displayed below, and each reader can make up his or her own mind.

Agitation, mixing and mass transfer in simulated high viscosity fermentation broths

Gas-liquid mass transfer, agitator power consumption, rheology, gas-liquid mixing and gas hold-up have been studied in an agitated, sparged vessel of diameter, T = 0.3 m, with a liquid capacity of 0.02 m$^3$, unaerated liquid height = 0.3 m. The solutions of sodium carboxymethylcellulose used exhibit moderate viscoelasticity and shear thinning behaviour, obeying the power law over the range of shear rates studied. The gas-liquid mass transfer was studied using a steady state technique. This involves monitoring the gas and liquid phase oxygen concentrations when a microorganism (yeast) is cultured in the solutions of interest. Agitator power consumption was measured using strain gauges mounted on the impeller shaft. Various agitator geometries were used. These were: Rushton turbines ( D = T/3 and D = T/2 ), used singly and in pairs; Intermig impellers ( D = 0.58T ), used as a pair; and a 45° pitched blade turbine ( D = T/2 ), used in combination with a Rushton turbine. Gas hold-up and gas-liquid flow patterns were visually observed. In addition, the state of the culture variables, (oxygen uptake rate and carbon dioxide production rate), were used to provide a respiratory quotient, the value of which can be linked to the degree of gas-liquid mixing in the vessel. Measurement of point values of the liquid phase oxygen concentration is also used to indicate the degree of liquid mixing attained. The volumetric mass transfer coefficient, k$_L$a, was found to be dependent on the conditions in which the yeast was cultivated, as well as being a function of time. These variations were associated with variations in solution composition seen over the course of each experiment. Steps were taken to ensure that further k$_L$a values were measured under identical conditions of the culture variables, in order to determine the effect on k$_L$a of varying viscosity, agitator speed and type and air flow rate. Increasing solution viscosity results in poorer gas-liquid mixing and a reduction in k$_L$a, as has been found by earlier workers. Thus high agitator speeds and power inputs are required to maintain adequate mass transfer rates. In the more viscous solutions used, large diameter dual impeller systems were required, to mix the gas and liquid phases. Of these a pair of Rushton turbines ( D = T/2 ) gave the highest k$_L$a values at a given power input. In these solutions the dependence of k$_L$a on the gassing rate, which is seen in intermediate and low viscosity solutions, virtually disappears, with k$_L$a highly dependent on the power input and the apparent viscosity. At intermediate viscosities a smaller pair of Rushton turbines showed the most efficient mass transfer characteristics, here k$_L$a is dependent on the power input and the gassing rate, but independent of viscosity. This is linked to the flow regime force in the vessel, which at intermediate viscosities lies in the transition region between the laminar and turbulent flow regimes. Variations in gas hold-up, rising then falling with increasing impeller speed, were linked to variations in the gassed power number, falling then rising with increasing impeller speed. These effects are considered to be due to variations in the size of the gas filled cavities behind the impeller blades

ENVIRONMENTAL REGULATORY POLICY: POLITICAL ECONOMY, INDUSTRIAL GEOGRAPHY, AND INTERGOVERNMENTAL FISCAL EFFECTS

Environmental regulatory policy in the U.S. is a mixture of federal, state, and local activity and impacts. This is true of air quality regulations, which are governed at the federal level by the Clean Air Act. This dissertation analyzes both the political economy of federal environmental regulations and the empirical effects of ozone regulations under the Clean Air Act.A political economy model is developed that offers a motivation for political support of national environmental policy that regulates strictly local pollution. Altering local environmental policies in other jurisdictions will cause capital migration, which may increase local welfare. Thus, individuals have an incentive to influence local policies in other jurisdictions. National environmental policy then becomes a potential tool for inter-jurisdictional competition.The empirical impacts of ground-level ozone regulations under the Clean Air Act are also analyzed. The Clean Air Act established minimum air quality standards; localities failing to meet the established standards are classified as nonattainment areas and are subject to additional environmental regulations. These new regulations have a direct impact on polluting industries, and therefore also an indirect impact on the revenues and expenditures of local governments.First, nonattainment status is seen to alter regional industrial geography. Overall economic activity declines in both nonattainment areas and the surrounding jurisdictions. Gaining attainment status partially mitigates these impacts, although to some extent theeconomic impacts in both nonattainment areas and the surrounding jurisdictions do permanently persist. I also find evidence that manufacturing activity relocates from nonattainment areas to surrounding areas that face more lenient air quality regulations.Ozone nonattainment status is also seen to produce fiscal effects for local governments as changes in industrial geography alter local tax bases. Revenues and expenditures decline in regulated population centers, while they increase in surrounding areas. These increases diminish with distance from the urban center. Also, the fiscal impacts persist even after attainment status has been gained