Complexity and maintenance : a comparative study of object-oriented and structured methodologies : a thesis presented in partial fulfilment of the requirements for the degree of Master of Business Studies in Information Systems at Massey University

Maintenance has been found to be one of the most expensive phases in the life of an information system. It has been suggested that the use of object-oriented methods instead of traditional structured methods may be one way of reducing the cost of maintenance required for an information system. This thesis is an attempt to determine whether the object-oriented approach does in fact undergo a relatively smaller increase in complexity when subjected to a change in specifications than a similar system that is developed using a "structured methodology", and is therefore easier to maintain. The methodologies used in this study were Yourdon's (1989) Modern Structured Methodology and Booch's (1994) Object-Oriented methodology. The analysis phase of both methodologies were applied to the same case study twice in order to evaluate the effects of a change in the system's specifications. Once the two models for each methodology were complete, various metrics were applied to the structured system and a separate set of metrics were applied to the object-oriented system. The results of the models and the metrics were then analysed and validated in order to determine which system suffered a smaller proportional increase in complexity as a result of the changes to the system. It was found that overall, the object-oriented system proved to undergo a smaller increase in complexity, and it was therefore easier to maintain as a result of the changes than the structured system

A limnological assessment of Russell Pond, Woodstock, New Hampshire

A limnological survey was conducted during 17-18 September, 1998 to characterize the trophic state of Russell Pond, a 15.8 Ha natural Lake located in Woodstock, Grafton County, New Hampshire. Physical, biological and chemical parameters were measured to assess the health of the lake and changes from previous studies. Russell Pond is oligotrophic with high Secchi disk depths (13.8 m), low phosphorus levels (3.8 µg L1) and low Chlorophyll a concentration (0.5 µg L-1). Peridinium (Dinophyceae) dominated (64%) the net phytoplankton. Calanoid copepods (Diaptomidae) constituted 87.5% of the crustacean zooplankton. The lake is at risk for acidification because of low acid neutralizing capacity (1.2 mg CaCO3 L-1) and low pH (5.6) in the deep water. Russell Pond has exceptionally high water clarity due to the low phytoplankton density and low water color (6.9 CPU). Water quality of the lake has been stable over the past few years. Compared to data from four other New Hampshire lakes, Russell Pond is the most oligotrophic of the lakes, followed by Pleasant Lake and Stonehouse Pond. Great Pond and Townhouse Pond were the most mesotrophic of the lakes

From locally conformally K\"ahler to bi-Hermitian structures on non-K\"ahler complex surfaces

We prove that locally conformally K\"ahler metrics on certain compact complex surfaces with odd first Betti number can be deformed to new examples of bi-Hermitian metrics.Comment: minor revision, final versio

Who visits World Heritage? A comparative analysis of three cultural sites

Heritage tourism is a growing segment of the modern tourism industry, and several studies have been undertaken to identify the individuals who participate in this type of tourism. These have indicated that heritage tourists, generally, are middle class, middle age, and well educated. However, despite their iconic role, there has been relatively little attention paid to profile of visitors to World Heritage Sites. This study aims to better understand the demography of this specific tourism segment through the use of survey-based research at three geographically diverse World Heritage Sites: Independence Hall in the USA, Studenica Monastery in Serbia, and the Archaeological Site of Volubilis in Morocco. Through the use of descriptive statistics, several over-arching trends were noted among the three sites. World Heritage Site visitors were found to be very well educated, but they did not have any similarities in relation to age, income, or residence, which contrasts the “general” heritage tourist typology. However, there were several World Heritage specific trends. While this work is a snapshot of the three sites under study and thus is difficult to generalize, it provides the basis for more comprehensive demographic research on visitors to World Heritage Sites

Portal Venous Thrombosis Associated with Use of Etonogestrel/ethinyl Estradiol Vaginal Ring

Introduction: Portal venous thrombosis is a life-threatening cause of abdominal pain. In younger patients, heritable thrombophilias, pregnancy, tobacco use, and oral contraceptives are associated.Case Report: A 26-year-old woman prescribed contraceptive vaginal ring presented with abdominal pain and was diagnosed with an extensive portal venous thrombosis. Management included heparin and later an oral anticoagulant with good short-term outcome.Discussion: Women using hormonal contraception are approximately four times more likely to develop thromboembolism. Risk of thromboembolism is similar between users of intravaginal and oral contraceptives.Conclusion: Portal venous thrombosis must be considered in women presenting with abdominal pain who are prescribed hormonal contraceptives, including intravaginal forms

Multiple differences in calling songs and other traits between solitary and gregarious Mormon crickets from allopatric mtDNA clades

The Linnaean Society, The British Ecological Society, The Russell Trust (St. Andrews), The Orthopterists' Society and an NSERC (Canada) grant to DTG. Gordon S. Brown provided assistance with digital imaging and morphological measurements.Background: In acoustic species, traits such as male calling song are likely to diverge quickly between allopatric populations due to sexual selection, and divergence in parameters such as carrier frequency, chirp structure, and other important song characters can influence sexual isolation. Here we make use of two forms of Mormon crickets to examine differences in a broad suite of traits that have the potential to influence speciation via sexual isolation. Mormon crickets in "gregarious" populations aggregate into dense migratory bands, and females are the sexually competitive Fsex ( sex- role reversal). There is also a non-outbreak "solitary" form. These two forms are largely but not perfectly correlated with a significant mtDNA subdivision within the species that is thought to have arisen in allopatry. Combined information about multiple, independently evolving traits, such as morphology and structural and behavioural differences in calling song, provides greater resolution of the overall differences between these allopatric populations, and allows us to assess their stage of divergence. We test two predictions, first that the forms differ in song and second that gregarious males are more reluctant to sing than solitary males due to sex role reversal. We also tested for a difference in the relationship between the size of the forewing resonator, the mirror, and carrier frequency, as most models of sound production in crickets indicate that mirror size should predict carrier frequency. Results: Multivariate analyses showed that solitary and gregarious individuals from different populations representing the two mtDNA clades had almost non-overlapping distributions based on multiple song and morphological measurements. Carrier frequency differed between the two, and gregarious males were more reluctant to sing overall. Mirror size predicted carrier frequency; however, the relationship between mirror size and surface area varied between solitary and gregarious forms, suggesting that factors above and beyond mirror size contribute to carrier frequency. Conclusion: The two clades of Mormon crickets differ in a broad suite of independent traits that probably justify subspecies status ( the two can successfully mate so may not be reproductively isolated). However, our results emphasize the importance of carefully distinguishing the ultimate causation of differences between traits used to delineate species or subspecies boundaries.Publisher PDFPeer reviewe

Solar Obliquity Induced by Planet Nine

The six-degree obliquity of the sun suggests that either an asymmetry was present in the solar system's formation environment, or an external torque has misaligned the angular momentum vectors of the sun and the planets. However, the exact origin of this obliquity remains an open question. Batygin & Brown (2016) have recently shown that the physical alignment of distant Kuiper Belt orbits can be explained by a 5-20 Earth-mass planet on a distant, eccentric, and inclined orbit, with an approximate perihelion distance of ~250 AU. Using an analytic model for secular interactions between Planet Nine and the remaining giant planets, here we show that a planet with similar parameters can naturally generate the observed obliquity as well as the specific pole position of the sun's spin axis, from a nearly aligned initial state. Thus, Planet Nine offers a testable explanation for the otherwise mysterious spin-orbit misalignment of the solar system.Comment: 8 pages, 4 figures, manuscript #: AAS01477, submitted on June 24, 201