Wireless local area network planning: an overview

When planning a wireless local area network, there are design issues that need to be considered. In this paper, the fundamentals of planning a wireless local area network are introduced and discussed to highlight the requirements involved. Network constraints, as their relevance to wireless network design is investigated. The paper concludes with an overview of wireless network planning solutions including commercial and free software, and an introduction to the author’s research

Design of a processor to support the teaching of computer systems

Teaching computer systems, including computer architecture, assembly language programming and operating system implementation, is a challenging occupation. At the University of Waikato this is made doubly true because we require all computer science and information systems students study this material at second year. The challenges of teaching difficult material to a wide range of students have driven us to find ways of making the material more accessible. The corner stone of our strategy for delivering this material is the design and implementation of a custom CPU that meets the needs of teaching. This paper describes our motivation and these needs. We present the CPU and board design and describe the implementation of the CPU in an FPGA. The paper also includes some reflections on the use of a real CPU rather than a simulation environment. We conclude with a discussion of how the CPU can be used for advanced classes in computer architecture and a description of the current status of the project

Improving the performance of HTTP over high bandwidth-delay product circuits

As the WWW continues to grow, providing adequate bandwidth to countries remote from the geographic and topological center of the network, such as those in the Asia/Pacific, becomes more and more difficult. To meet the growing traffic needs of the Internet some Network Service Providers are deploying satellite connections. Through discrete event simulation of a real HTTP workload with differing international architectures this paper is able to give guidance on the architecture that should be deployed for long distance, high capacity Internet links. We show that a significant increase in the time taken to fetch HTTP requests can be expected when traffic is moved from a long distance international terrestrial link to a satellite link. We then show several modifications to the network architecture that can be used to greatly improve the performance of a satellite link. These modifications include the use of an asymmetric satellite link, the multiplexing of multiple HTTP requests onto a single TCP connection and the use of HTTP1.1

The interaction of metal ions at the hydrous manganese dioxide-solution interface

Submitted in partial fulfillment of the requirements of the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June, 1973An experimental study of the interaction of metal ions with the surface of hydrous manganese dioxide has been completed. The results of these experiments have greatly improved our qualitative understanding of the adsorption mechanism and have also provided a means of testing quantitatively the proposal that the concentration of cobalt in manganese rich marine samples is due to adsorption of cobalt from sea water by hydrous manganese dioxide. This study has shown that there are two reasons why manganese dioxide is an efficient scavenger of metal ions from sea water. These are coulombic attraction and specific adsorption. The coulombic attraction is in response to the surface charge that originates because of acid-base reactions at the surface. The surface charge is pH dependent, and the pH of zero point of charge for the hydrous manganese dioxide used in this study was 2.25. The surface charge increases rapidly for pH values greater than the pH of zero point of charge and reaches values of -100 μcoul/cm2 by pH 8.0. However, the high surface charge cannot explain all the adsorption. This is because some metal ions exhibìt a strong specific adsorption on the surface. This specific adsorption is a direct reaction of the metal ions with the surface, releasing one proton from the surface for each metal ion adsorbed. The energy of this specific interaction is frequently greater than the energy of electrostatic attraction. Adsorption on hydrous manganese dioxide and the magnitude of the specific adsorption both increased in the order: Na = K < Mn < Ca < Sr < Ba < Ni < Zn < Mn ≤ Co This suggests that the specific adsorption potential controls the adsorption selectivity of δMn02. An adsorption isotherm was constructed for cobalt, and these data were used to test the hypothesis that the enrichment of cobalt in the suspended matter of the Black Sea and in ferromanganoan sediments from the East Pacific Rise is due to adsorption of cobalt from sea water by manganese dioxide. The calculations indicate that adsorption is a feasible explanation for these examples.This research has been supported for various periods by funds granted by the National Science Foundation (GA-l3574) and U. S. Atomic Energy Commission Contract AT-(30-1)3566 and Graduate Fellowships provided by the Pan American Petroleum Foundation and by the Woods Hole Oceanographic Institution

Natural Enemies of Cranberry Fruitworm, \u3ci\u3eAcrobasis Vaccinii\u3c/i\u3e, (Lepidoptera: Pyraudae) in Michigan Highbush Blueberries

A two-year study was conducted in Michigan highbush blueberries to determine the complex of parasitoids attacking cranberry fruitworm, Acrobasis vaccinii. Eight parasitoid species and one fungal pathogen were collected. Parasitism of collected hosts ranged from 6.6% to 28.1%. The more common larval parasitoid encountered was Campoletis patsuiketorum (Hymenoptera: Ichneumonidae). The more common parasitoid recovered from fruitworm hibernacula was Villa lateralis (Diptera: Bombyliidae). This study documented six unreported natural enemies of cranberry fruitworm, including C. patsuiketorum; V. lateralis; Diadegma compressum (Hymenoptera: Ichneumonidae); Compsilura concinnata (Diptera: Tachinidae); Memorilla pyste (Diptera: Tachinidae); an undescribed Microtypus species (Hymenoptera: Braconidae); and a fungal pathogen, Paecilomyces near farinosus. This is the first known host association for the undescribed Microtypus species, and increases the known parasitoid complex of cranberry fruitworm to 17 species

Mappa mundi : mapping culture, mapping the world

Humanities Research Group Working Papers 9https://scholar.uwindsor.ca/hrg-working-papers/1008/thumbnail.jp

Income Tax Evasion

Jamaica\u27s 1986 personal income tax reform moved the nation well along toward tax simplification, a more uniform and fair treatment of taxpayers, removal of disincentives to in­creased work effort and to work effort allocation across sectors and a more level playing field for investment. The major elements of the reform are a flat rate income tax, a higher income exemption level, and the elimination of all tax credits and most nontaxable perquisites. While the impact of the reform on revenues and on the burden of various types of taxpayers has been carefully analyzed, much less has been done in terms of studying the impact on those who do not pay -- ­those who evade the income tax by either under­reporting or not filing. This paper presents estimates of the amount, structure and deter­minants of evasion by Jamaica\u27s hard-to-tax sec­tor, the self-employed. It should be emphasized at the outset that Jamaica\u27s problems with income tax evasion are not solved by the flat tax. While the new system lessens the rewards for evasion and through simplification makes compliance and monitoring easier, it will not automatically draw the self­-employed into the tax net. Why would a person who is successful at evading tax at a 57 1/2 percent marginal rate voluntarily come forward to pay because the rate has been dropped to 33 1/3 per­cent? The structural reform must be accompanied by a vigorous program of administrative im­provements. This is all the more reason to conduct a careful analysis of the amount and structure of income tax evasion. How much additional tax revenue could be captured in an effective pro­gram of enforcement, and what income groups, occupations, etc., should be targeted for increased coverage, examination and audit? The next section of this chapter summarizes the results of analyses of the national income accounts and the taxpaying characteristics of a random sample of six professional occupations. Both approaches are meant to infer the total amount of self-employed income tax evasion. The methodology used in drawing and analyzing a much larger and more representative sample of self-employed individuals is discussed in the fol­lowing section. Then we turn in the next three sections to the heart of this work: an analysis of filing rates and of the characteristics of self-­employed filers, an analysis of the revenue loss that results from those who do not file, and an analysis of audit/examination reports to estimate and explain the degree of underreporting by self­-employed filers. The final section of the paper is concerned with how tax policy and tax administration might be altered to draw the self­-employed into the tax net