76 research outputs found
Genetic Micro-Programs for Automated Software Testing with Large Path Coverage
Ongoing progress in computational intelligence (CI) has led to an increased
desire to apply CI techniques for the purpose of improving software engineering
processes, particularly software testing. Existing state-of-the-art automated
software testing techniques focus on utilising search algorithms to discover
input values that achieve high execution path coverage. These algorithms are
trained on the same code that they intend to test, requiring instrumentation
and lengthy search times to test each software component. This paper outlines a
novel genetic programming framework, where the evolved solutions are not input
values, but micro-programs that can repeatedly generate input values to
efficiently explore a software component's input parameter domain. We also
argue that our approach can be generalised such as to be applied to many
different software systems, and is thus not specific to merely the particular
software component on which it was trained.Comment: A version of this paper has been accepted for publication in CEC'2
Biogeochemical and ecological impacts of boundary currents in the Indian Ocean
Monsoon forcing and the unique geomorphology of the Indian Ocean basin result in complex boundary currents, which are unique in many respects. In the northern Indian Ocean, several boundary current systems reverse seasonally. For example, upwelling coincident with northward-flowing currents along the coast of Oman during the Southwest Monsoon gives rise to high productivity which also alters nutrient stoichiometry and therefore, the species composition of the resulting phytoplankton blooms. During the Northeast Monsoon most of the northern Indian Ocean boundary currents reverse and favor downwelling. Higher trophic level species have evolved behavioral responses to these seasonally changing conditions. Examples from the western Arabian Sea include vertical feeding migrations of a copepod (Calanoides carinatus) and the reproductive cycle of a large pelagic fish (Scomberomorus commerson). The impacts of these seasonal current reversals and changes in upwelling and downwelling circulations are also manifested in West Indian coastal waters, where they influence dissolved oxygen concentrations and have been implicated in massive fish kills. The winds and boundary currents reverse seasonally in the Bay of Bengal, though the associated changes in upwelling and productivity are less pronounced. Nonetheless, their effects are observed on the East Indian shelf as, for example, seasonal changes in copepod abundance and zooplankton community structure. In contrast, south of Sri Lanka seasonal reversals in the boundary currents are associated with dramatic changes in the intensity of coastal upwelling, chlorophyll concentration, and catch per unit effort of fishes. Off the coast of Java, monsoon-driven changes in the currents and upwelling strongly impact chlorophyll concentrations, seasonal vertical migrations of zooplankton, and sardine catch in Bali Strait.
In the southern hemisphere the Leeuwin is a downwelling-favorable current that flows southward along western Australia, though local wind forcing can lead to transient near shore current reversals and localized coastal upwelling. The poleward direction of this eastern boundary current is unique. Due to its high kinetic energy the Leeuwin Current sheds anomalous, relatively high chlorophyll, warm-core, downwelling eddies that transport coastal diatom communities westward into open ocean waters. Variations in the Leeuwin transport and eddy generation impact many higher trophic level species including the recruitment and fate of rock lobster (Panulirus cygnus) larvae. In contrast, the transport of the Agulhas Current is very large, with sources derived from the Mozambique Channel, the East Madagascar Current and the southwest Indian Ocean sub-gyre. Dynamically, the Agulhas Current is upwelling favorable; however, the spatial distribution of prominent surface manifestations of upwelling is controlled by local wind and topographic forcing. Meanders and eddies in the Agulhas Current propagate alongshore and interact with seasonal changes in the winds and topographic features. These give rise to seasonally variable localized upwelling and downwelling circulations with commensurate changes in primary production and higher trophic level responses. Due to the strong influence of the Agulhas Current, many neritic fish species in southeast Africa coastal waters have evolved highly selective behaviors and reproductive patterns for successful retention of planktonic eggs and larvae. For example, part of the Southern African sardine (Sardinops sagax) stock undergoes a remarkable northward migration enhanced by transient cyclonic eddies in the shoreward boundary of the Agulhas Current.
There is evidence from the paleoceanographic record that these currents and their biogeochemical and ecological impacts have changed significantly over glacial to interglacial timescales. These changes are explored as a means of providing insight into the potential impacts of climate change in the Indian Ocean
The theory of the foreign exchanges.
First edition.Mode of access: Internet
The cultivation and use of imagination.
Mode of access: Internet
Essays and addresses on economic questions (1865-1893)
Mode of access: Internet
Die lehre vom weehselkurs ["The theory of the foreign exchanges"
Mode of access: Internet
Incompatibility of lognormal forward-Libor and Swap market models
Includes bibliographical references (p. 156-160).The lognormal forward-Libor and Swap market models were formulated to price caps and swaptions. However, the prices computed by these two models, under equivalent measures, are reported to be unequal. This study investigates this incompatibility by computing the prices of caps and swaptions under both the forward Libor measure and the forward Swap measure, in both the Libor and Swap market models. This was done by building a computer program that implements the Monte Carlo versions of the models, using data from caps and swaptions traded in the South African market. It was found that the actual price of caps, using the same implied volatility, were simulated accurately in both the Libor and Swap market models under both the forward Libor measure and the forward Swap measure. On the other hand, although the actual swaption prices were also simulated accurately in both the Libor and Swap market models under both the forward Libor measure and the forward Swap measure, a different implied volatility was used for each model. Therefore, the swaption price computed by the Libor market model was inconsistent with the price generated by the Swap market model; the two models are indeed incompatible. In order to price interest rate derivatives consistently, either the Libor market model or the Swap market model must be chosen. Since the Libor market model priced consistently under the two forward measures, and the time taken to simulate a price in the Libor market model was much less than in the Swap market model, the practice in the market to use the Libor market model in favour of the Swap market model is justified
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