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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
431

E-cosmic: A Business Process Model Based Functional Size Estimation Approach

Kaya, Mahir 01 February 2010 (has links) (PDF)
The cost and effort estimation of projects depend on software size. A software product size is needed at as early a phase of the project as possible. Conventional Early Functional Size Estimation methods generate size at the early phase but result in subjectivity and unrepeatability due to manual calculation. On the other hand, automated Functional Size Measurement calculation approaches require constructs which are available in considerably late software development phases. In this study we developed an approach called e-Cosmic to calculate and automate the functional size measurement based on the business processes. Functions and input and output relationship types of each function are identified in the business process model. The size of each relationship type is determined by assigning appropriate data movements based on the COSMIC Measurement Manual. Then, relationship type size is aggregated to produce the size of each function. The size of the software product is the sum of the size of these functions. Automation of this process based on business process model is performed by developing a script in the ARIS tool concept. Three case studies were conducted to validate the proposed functional size estimation method (e-Cosmic). The size of the products in the case studies are measured manually with COSMIC FSM (Abran et al, 2007) as well as using a conventional early estimation method, called Early and Quick COSMIC FFP. We compared the results of different approaches and discussed the usability of e-Cosmic based on the findings.
432

Ultraschalldämpfungsspektroskopie grobdisperser Systeme

Richter, Andreas 09 August 2008 (has links) (PDF)
Die Charakterisierung von Nanopartikeln erfordert eine Messung des Dispersitätszustandes bei allen Schritten der Herstellung - von der Synthese bis zum fertigen Produkt. Dafür ist eine leistungsfähige Partikelmesstechnik notwendig, deren Methoden bei der Beschreibung des komplexen Materialverhaltens helfen können. Die Ultraschalldämpfungsspektroskopie ist eine Messmethode, die zur prozessbegleitenden Charakterisierung hochdisperser Pulver und Suspensionen geeignet ist. Mit Vergleichen von Messungen und Modellrechungen wurde festgestellt, dass für die Ultraschalldämpfungs-Modellierung in Dispersionen homogener Partikel ein auf dem Phänomen der elastischen Streuung basierendes Modell praktisch relevant ist. Dies betrifft sowohl die Anwendung zur Messung in Suspensionen als auch in Emulsionen homogener Partikel. Bei einem Vergleich von Modellrechungen und Messungen für ein System poröser Partikel bzw. Aggregate wurde das Modell der Streuung an poroelastischen Kugeln als geeignet zur Beschreibung der Dämpfung disperser Systeme identifiziert. Bei Vorhandensein grober Partikel in Suspensionen nanoskaliger Systeme ist somit eine korrekte Auswertung der Partikelgröße möglich; der bislang übliche Messbereich wurde erweitert. Sekundärer Schwerpunkt der Arbeit ist die Diskussion der numerischen Modellanwendung. Es werden weiterhin Lösungsmöglichkeiten zur Dämpfungsberechnung und zur Berechnung der Größenverteilungen beschrieben. Des Weiteren wurden Anregungen für Entwickler von Ultraschallspektrometern abgeleitet.
433

Reproductive Biology of the Southern Dwarf Siren, Pseudobranchus axanthus, in Southern Florida

Adcock, Zachary Cole 01 January 2012 (has links)
The salamander family Sirenidae is composed of two extant genera, Siren and Pseudobranchus, each with two known species. Several questions regarding Sirenidae life history persist, and much of the available life history data for Pseudobranchus are attributed to studies of P. axanthus in northern Florida. Information on the reproductive biology of P. axanthus is limited, and historical references often suggest contradictory results. This study was undertaken to clarify information and expand on the limited data regarding P. axanthus reproductive biology, specifically for southern Florida populations. The study population was most likely the P. a. belli subspecies. P. axanthus in southern Florida exhibited year round, continuous reproduction with oviposition documented in nine months. Potential clutch size was positively correlated to female size. The largest observed potential clutch was a female with 58 pre-ovulatory oocytes. The largest observed bout was a female with 15 oviductal eggs. Female P. axanthus in southern Florida oviposited eggs singly and at total densities of 3-4 eggs/m2. Developmental time to egg hatching lasted about 30 days, larvae hatched at 16mm TL, and minimum size at female sexual maturity was 115mm TL and 72mm SVL. The reproductive biology of P. axanthus was distinctly contrasting to other members of the family Sirenidae, S. intermedia and S. lacertina, that occupy the same habitat at the same study location.
434

An analytical approach to computing step sizes for finite-difference derivatives

Mathur, Ravishankar 29 June 2012 (has links)
Finite-difference methods for computing the derivative of a function with respect to an independent variable require knowledge of the perturbation step size for that variable. Although rules of thumb exist for determining the magnitude of the step size, their effectiveness diminishes for complicated functions or when numerically solving difficult optimization problems. This dissertation investigates the problem of determining the step size that minimizes the total error associated with finite-difference derivative approximations. The total error is defined as the sum of errors from numerical sources (roundoff error) and mathematical approximations (truncation error). Several finite-difference approximations are considered, and expressions are derived for the errors associated with each approximation. Analysis of these errors leads to an algorithm that determines the optimal perturbation step size that minimizes the total error. A benefit of this algorithm is that the computed optimal step size, when used with neighboring values of the independent variable, results in approximately the same magnitude of error in the derivative. This allows the same step size to be used for several successive iterations of the independent variable in an optimization loop. A range of independent variable values for which the optimal step size can safely remain constant is also computed. In addition to roundoff and truncation errors within the finite-difference method, numerical errors within the actual function implementation are also considered. It is shown that the optimal step size can be used to compute an upper bound for these condition errors, without any prior knowledge of the function implementation. Knowledge of a function's condition error is of great assistance during the debugging stages of simulation design. Although the fundamental analysis assumes a scalar function of a scalar independent variable, it is later extended to the general case of a vector function of a vector independent variable. Several numerical examples are shown, ranging from simple polynomial and trigonometric functions to complex trajectory optimization problems. In each example, the step size is computed using the algorithm developed herein, a rule-of-thumb method, and an alternative statistical algorithm, and the resulting finite-difference derivatives are compared to the true derivative where available. / text
435

Assessment of sterol metabolism in sitosterolemia

Othman, Rgia Ali 11 1900 (has links)
Sitosterolemia (STSL) is a sterol storage disorder characterized by very high plasma plant sterol (PS) and 5α-stanol levels, and leads to premature atherosclerosis, xanthomas, macrothrombocytopenia and endocrine disruption. Ezetimibe (EZE), a sterol absorption inhibitor, reduces plasma PS levels in STSL but its effect on tissue pool of sterols has not been investigated yet. The research objectives were to assess if EZE reduces whole body sitosterol and cholesterol pool sizes, improves cholesterol homeostasis, enhance hematologic profile and reduce endocrine disruption in STSL. EZE effects on circulating levels of cholestanol and its precursors (cholesterol and bile acid derivative 7α-hydroxy-4-cholesten-3-one, 7α-H-C4) relative to exogenous stanols (sitostanol) were also studied. Eight STSL patients were taken off EZE for 14 wks. After 4 wks off EZE they received intravenous doses of D7-sitosterol and 18O-cholesterol for sterol pool sizes assessments, and oral doses of 13C-cholesterol and deuterium oxide to measure fractional cholesterol absorption and synthesis rates. EZE (10 mg/d) was resumed and stable isotopes testing repeated. Measurement parameters included isotopic sterol enrichments, blood cell count, plasma and red blood cell (RBC) PS, cholesterol and its precursor (lathosterol), 5α-stanols and plasma 7α-H-C4, and thyroid hormones levels. EZE reduced plasma levels of sitosterol and total cholesterol, whole body sitosterol and cholesterol pool sizes and fractional cholesterol absorption rate while increasing cholesterol synthesis, production and clearance rates. EZE increased platelet count and decreased platelet size without affecting RBC indices of size or mass. A substantial decrease in circulating sitostanol but moderate decrease of cholestanol was noted with EZE. EZE increased lathosterol but not 7α-H-C4, suggesting increases in cholesterol biosynthesis and thus precursor availability for synthesis of cholestanol. In summary, EZE reduces body stores of PS and cholesterol, and increases cholesterol turnover by reducing cholesterol absorption and enhancing its synthesis and clearance. EZE reduces circulating PS and 5α-stanol levels, and improves macrothrombocytopenia and thyroid disruption. Endogenous cholestanol in STSL is mainly derived from cholesterol but not bile acid synthesis pathway. These data suggest that EZE may reduce the risks of developing premature atherosclerosis, bleeding and hormone disruption, thereby reinforcing the rationale for the use of EZE in treatment of STSL. / February 2015
436

An analysis of changing official policies on class size in Hong Kong primary schools and their implications

Chan, Fu-man., 陳輔民. January 1994 (has links)
published_or_final_version / Education / Master / Master of Education
437

CRITERIA FOR CHANGING SCHOOL ATTENDANCE BOUNDARIES

DiGregori, George William, 1925- January 1974 (has links)
No description available.
438

Genome Size Diversity and Patterns within the Annelida

Forde, Alison Christine 24 January 2013 (has links)
This thesis concerns genomic variation within the Annelida, for which genome size studies are few and provide data for only a handful of groups. Genome size estimates were generated using Feulgen image analysis densitometry for 35 species of leeches and 61 polychaete species. Relationships were explored utilizing collection location and supplementary biological data from external sources. A novel, inverse correlation between genome size and maximum adult body size was found across all leeches. Leeches that provide parental care had significantly larger genome sizes than leeches that do not. Additionally, specimens identified as Nephelopsis obscura exhibited geographic genome size variation. Within the Polychaeta, Polar region polychaete genomes were significantly larger than those of Atlantic and Pacific polychaetes. These studies represent the first exploration of leech genome sizes, and provide base evidence for numerous future studies to examine relationships between genome size and life history traits across and within different annelid groups.
439

Life-history traits and potential causes of clutch-size decline in the introduced song thrush (Turdus philomelos) in New Zealand

Congdon, Nicola Maree January 2010 (has links)
The song thrush (Turdus philomelos) was introduced to New Zealand from Britain during the mid 19th century and has become one of the most common terrestrial bird species in New Zealand. In this study, I surveyed a range of life-history traits in New Zealand song thrushes for comparison with traits of British thrushes. Clutch size, egg size and nest size have decreased, while the nestling period is shorter and the incubation period longer. This combination of changes suggests birds are investing less energy into each reproductive bout. Birds also appear unable to raise large broods, as nestling starvation is common in New Zealand, which suggests that food is limiting. I experimentally tested the ability of song thrushes to incubate enlarged clutches and broods, but productivity was not higher for enlarged broods and natural 3- and 4-egg clutches produced similar numbers of fledglings. Thus reduced clutch size may be an adaptation to the local environment. Differences in female incubation behaviour, with 3- and 4-egg clutches receiving higher levels of incubation and more visits per hour than 5-egg clutches, also suggest New Zealand thrushes have difficulty coping with clutches as large as those in Britain. The decrease in clutch size between New Zealand and Britain is in the direction and magnitude expected based on the change in latitude, which supports the hypothesis that factors affecting foraging time and food availability, such as daylength, temperature and rainfall, may be selecting for smaller clutches. Egg size was also found to have decreased in New Zealand, though this may be the result of smaller adult size. Hatchling mass was related to egg volume, but I found no effect of egg volume or clutch size on hatching success. However, nests containing more pointed eggs (i.e., abnormally-shaped eggs), had lower survival and hatching/fledgling success. Data from the national nest record database and my study both suggest that differences in song thrush productivity are the result of differential survival of nestlings. Nestling mortality due to starvation was common at Kowhai Bush, but rare in Britain, so either adult condition or food availability may be lowering reproductive success in New Zealand. High rates of nest failure (>65%) could also affect clutch size, but the strong directional selection imposed by food limitation during the nestling period suggests that increases in food supply would result in increased reproductive success even with the same levels of nest failure. When comparing clutch size throughout New Zealand, I found a significant, positive relationship with rainfall, which further suggests that food limitation may be the main factor driving changes in life-history traits of song thrushes in New Zealand.
440

An Architectural Dimensions Based Software Functional Size Measurement Method

Gencel, Cigdem 01 July 2005 (has links) (PDF)
This thesis study aims to examine the conceptual and theoretical differences of Functional Size Measurement (FSM) methods, to identify the improvement opportunities of these methods and to develop a new FSM method. A comprehensive literature review is performed and two multiple-case studies are conducted as a research strategy. In the light of the results obtained, some improvement suggestions on two of the most challenging improvement opportunities identified for FSM methods are made &ndash / improvement opportunities which are related to the conceptual and theoretical basis of FSM and the extension of the applicability of these methods to different software functional domain types. The work behind these suggestions involves the critical examination of the concepts &ldquo / functionality&rdquo / and &ldquo / functional size&rdquo / and the depiction of &ldquo / types of functionality&rdquo / considering the components of software architecture and the forms of information processing logic performed in different software functional domain types. Based on the suggestions made, a new FSM method, called ARCHItectural DIMensions Based FSM (ARCHI-DIM) is developed conforming to the ISO/IEC 14143-1 standard. A third multiple-case study is conducted in order to evaluate the new method and to identify future directions for FSM methods.

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