The Multifactor Nature of the Volatility of Futures Markets

This paper estimates a model of interest rate dynamics containing multi-factor Wiener and single-factor Poisson jump volatility components. Data from the highly liquid but short term futures markets are used. The difficult numerical problem of estimating such multi-factor models is resolved by using a genetic algorithm to carry out the optimization procedure. It is established that the multi-factor Wiener volatility components are adequate to model the interest rate dynamics without the need to incorporate Poisson jump components, the existence of which would create difficulties in the practical use of interest rate models. Jel Classification No: C51, C61, E43     

Optimizing Grid-Based Workflow Execution

Large-scale applications can be expressed as a set of tasks with data dependencies between them, also known as application workflows. Due to the scale and data processing requirements of these applications, they require Grid computing and storage resources. So far, the focus has been on developing easy to use interfaces for composing these workflows and finding an optimal mapping of tasks in the workflow to the Grid resources in order to minimize the completion time of the application. After this mapping is done, a workflow execution engine is required to run the workflow over the mapped resources. In this paper, we show that the performance of the workflow execution engine in executing the workflow can also be a critical factor in determining the workflow completion time. Using Condor as the workflow execution engine, we examine the various factors that affect the completion time of a fine granularity astronomy workflow. We show that changing the system parameters that influence these factors and restructuring the workflow can drastically reduce the completion time of this class of workflows. We also examine the effect on the optimizations developed for the astronomy application on a coarser granularity biology application. We were able to reduce the completion time of the Montage and the Tomography application workflows by 90% and 50%, respectively.     

Accessing the spoken word

Spoken-word audio collections cover many domains, including radio and television broadcasts, oral narratives, governmental proceedings, lectures, and telephone conversations. The collection, access, and preservation of such data is stimulated by political, economic, cultural, and educational needs. This paper outlines the major issues in the field, reviews the current state of technology, examines the rapidly changing policy issues relating to privacy and copyright, and presents issues relating to the collection and preservation of spoken audio content .     

Surface Analysis of Chesapeake Bay Water Quality Response to Different Nutrient and Sediment Loads

Based on a set of Chesapeake Bay Estuarine Model (CBEM) scenarios, a three-dimensional response surface of a water quality index, such as chlorophyll concentration, versus a pair of loading constituents, e.g., nitrogen and phosphorus, is constructed. The responses of water quality, such as dissolved oxygen, chlorophyll, and water clarity, to nitrogen, phosphorus, and sediment loads are analyzed. From the response surface, a water quality response is estimated under loading conditions beyond that of a limited set of scenarios. Response surfaces may be used to determine the possible universe of nutrient and sediment load reductions needed to obtain a particular water quality standard and to examine the tradeoffs among nutrient and sediment load reductions that achieve the same water quality objective.     

Loose Coupling and Healthcare Organizations: Deployment Strategies for Groupware

Healthcare organizations are often organized in a modular, loosely coupled fashion where separate and semi-autonomous work units specialize in different areas of care delivery. This partitioning allows each unit to adapt to emerging practice standards in its area of expertise and to adjust to its local work environment. However, organizational loose coupling can limit the flow of information within organizations and can make it difficult to coordinate services when patients’ care is dependent on professionals from more than one unit. Groupware systems have the potential to improve coordination and information access in healthcare organizations. However, modularity and loose coupling make it difficult to introduce new systems when they span more than one unit, since authority is not always centralized and since perceptions and frames of reference on new deployments differ across units. In this paper, we define a groupware deployment framework for loosely coupled healthcare organizations that has two parts: a set of deployment challenges and a set of deployment strategies. The deployment challenges include: difficulties centralizing deployments, perceptions of inequity, role conflicts, and problems achieving critical mass. The deployment strategies outline a preliminary set of approaches for addressing the difficulties of deploying CSCW systems in loosely coupled healthcare organizations. We illustrate the framework by presenting a case study of a groupware deployment in a home care setting.     

Activation of acyl-CoA cholesterol acyltransferase: Redistribution in microsomal fragments of cholesterol and its facilitated movement by methyl-β-cyclodextrin

Acyl-CoA cholesterol acyltransferase (ACAT) (EC 2,3,1.26) in the yolk sac membrane of chicken eggs plays an important role in the transport of lipids, which serve as both structural components and as an energy source during embryogenesis. ACAT from the yolk sac membrane of chicken eggs 16 d after fertilization has higher activity and better stability than its mammalian liver counterpart. During our study of the avian enzyme, ACAI was found to be activated up to twofold during storage at 4°C. The activation was investigated, and data suggest that redistribution of cholesterol within microsomal vesicles leads to the increase. Methyl-β-cyclodextrin (MβCD) increases activation an additional twofold, possibly by facilitating the movement of cholesterol within microsomal fragments and allowing redistribution of cholesterol in lipid bilayers to a greater extent. Treatment of microsomes with MβCD removes cholesterol from the membranes. Controlled amounts of cholesterol can be restored to the membranes by mixing them with cholesterol-phosphatidylcholine liposomes in the presence of MβCD. Under these conditions, the plot of ACAT vs. cholesterol mole fraction in the liposomes is sigmoidal. The finding that MβCD can enhance cholesterol transfer between liposomes and microsomes and reduce the limitation of slow movement et nonpolar molecules in aqueous media should make cyclodextrins more useful in in vitro studies of apolar molecule transport between membrane vesicles.     

Size constancy in infants: 4-month-olds' responses to physical versus retinal image size.

This study tested whether 4-month-old infants respond primarily to objects' physical or retinal image sizes. In the study's main experiment, infants were habituated to either a 6-cm-diameter disk at a distance of 18 cm or a 10-cm disk at 50 cm. They were then given 2 test trials in which the 6- and 10-cm disks were presented side by side at a distance of 30 cm. For each infant, one test object had a novel physical size but a familiar retinal image size, and the other had a familiar physical size but a novel retinal image size. The infants exhibited a significant looking preference for the object that had a novel physical size. A preliminary experiment found that 4-month-olds' looking preferences are based on novelty, not familiarity, under the conditions of this study. Given this finding, the results suggest that 4-month-old infants attend and respond primarily to physical size, not to retinal image size. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the design of on-chip instruction caches

Cache memories reduce memory latency and traffic in computing systems. Most existing caches are implemented as board-based systems. Advancing VLSI technology will soon permit significant caches to be integrated on chip with the processors they support. In designing on-chip caches, the constraints of VLSI become significant. The primary constraints are economic limitations on circuit area and off-chip communications. The paper explores the design of on-chip instruction-only caches in terms of these constraints. The primary contribution of this work is the development of a unified economic model of on-chip instruction-only cache design which integrates the points of view of the cache designer and of the floorplan architect. With suitable data, this model permits the rational allocation of constrained resources to the achievement of a desired cache performance. Specific conclusions are that random line replacement is superior to LRU replacement, due to an increased flexibility in VLSI floorplan design; that variable set associativity can be an effective tool in regulating a chip's floorplan; and that sectoring permits area efficient caches while avoiding high transfer widths. Results are reported on economic functionality, from chip area and transfer width to miss ratio. These results, or the underlying analysis, can be used by microprocessor architects to make intelligent decisions regarding appropriate cache organizations and resource allocations.     

The ALFALFA Entomology Pest Identification System

Rule groups with preconditions,posteonditions,and termination conditions were added tothe ADVISE Meta-Expert System.Multiple,varying goals are also an attribute of the new rulegroups.By treating the data collection process as separating from the rule inference engine,techniques for enhanced data acquisition were developed using semantic networks to describerelations among variables and to restructure value sets for variables dynamically.Having thusextended the ADVISE tools,an automated key to alfalfa field pest identification was selected as atest application and found to be particularly well suited by the new features.A need fordisjunctive(“OR”)constructs in the right hand side of rules is discussed,and directions forfuture applications are given.