Physical Sciences and Mathematics Commons^™

Context-Aware Publish Subscribe In Mobile Ad Hoc Networks, Davide Frey, Gruia-Catalin Roman

All Computer Science and Engineering Research

The publish-subscribe communication paradigm is enjoying increasing popularity thanks to its ability to simplify the development of complex distributed applications. However, existing solutions in the publish-subscribe domain address only part of the challenges associated with the development of applications in dynamic scenarios such as mobile ad hoc networks. Mobile applications must be able to assist users in a variety of situations, responding not only to their inputs but also to the characteristics of the environment in which they operate. In this paper, we address these challenges by extending the publish-subscribe paradigm with the ability to manage and exploit context information …

Experimental Evaluation Of A Coarse-Grained Switch Scheduler, Charlie Wiseman, Jon Turner, Ken Wong, Brandon Heller

All Computer Science and Engineering Research

Modern high performance routers rely on sophisticated interconnection networks to meet ever increasing demands on capacity. Regulating the flow of packets through these interconnects is critical to providing good performance, particularly in the presence of extreme traffic patterns that result in sustained overload at output ports. Previous studies have used a combination of analysis and idealized simulations to show that coarse-grained scheduling of traffic flows can be effective in preventing congestion, while ensuring high utilization. In this paper, we study the performance of a coarse-grained scheduler in a real router with a scalable architecture similar to those found in high …

Improving Individual Flow Performance With Multiple Queue Fair Queuing, Manfred Georg, Christopher Jechlitschek, Sergey Gorinsky

All Computer Science and Engineering Research

Fair Queuing (FQ) algorithms provide isolation between packet flows, allowing max-min fair sharing of a link even when flows misbehave. However, fairness comes at the expense of per-flow state. To keep the memory requirement independent of the flow count, the router can isolate aggregates of flows, rather than individual flows. We investigate the feasibility of protecting individual flows under such aggregate isolation in the context of Multiple Queue Fair Queuing (MQFQ), where the router maintains a fixed number of queues and associates multiple queues with each flow. MQFQ places packets in the shortest queue associated with their flow. The redundancy …

Configurable Component Middleware For Distributed Real-Time Systems With Aperiodic And Periodic Tasks, Yuanfang Zhang, Christopher Gill, Chenyang Lu

All Computer Science and Engineering Research

Many distributed real-time applications must handle mixed periodic and aperiodic tasks with diverse requirements. However, existing middleware lacks flexible configuration mechanisms needed to manage end-to-end timing easily for a wide range of different applications with both periodic and aperiodic tasks. The primary contribution of this work is the design, implementation and performance evaluation of the first configurable component middleware services for admission control and load balancing of aperiodic and periodic tasks in distributed real-time systems. Empirical results demonstrate the need for and effectiveness of our configurable component middleware approach in supporting different applications with periodic and aperiodic tasks.

Optimal Discrete Rate Adaptation For Distributed Real-Time Systems, Yingming Chen, Chenyang Lu, Xenofon Kutsoukos

All Computer Science and Engineering Research

Many distributed real-time systems face the challenge of dynamically maximizing system utility in response to fluctuations in system workload. We present the MultiParametric Rate Adaptation (MPRA) algorithm for discrete rate adaptation in distributed real-time systems with end-to-end tasks. The key novelty and advantage of MPRA is that it can efficiently produce optimal solutions in response to workload variations such as dynamic task arrivals. Through offline preprocessing MPRA transforms an NP-hard utility optimization problem to the evaluation of a piecewise linear function of the CPU utilization. At run time MPRA produces optimal solutions by evaluating the function based on the CPU …

Scheduling Induced Bounds And The Verification Of Preemptive Real-Time Systems, Terry Tidwell, Christopher Gill, Venkita Subramonian

All Computer Science and Engineering Research

Distributed real-time and embedded (DRE) systems have stringent constraints on timeliness and other properties whose assurance is crucial to correct system behavior. Our previous research has shown that detailed models of essential middleware mechanisms can be developed, composed, and for constrained examples verified tractably, using state of the art timed automata model checkers. However, to apply model checking to a wider range of real-time systems, particularly those involving more general forms of preemptive concurrency, new techniques are needed to address decidability and tractability concerns. This paper makes three contributions to research on formal verification and validation of DRE systems. First, …

Combined Controllers That Follow Imperfect Input Motions For Humanoid Robots, Gazihan Alankus, Burchan O. Bayazit

All Computer Science and Engineering Research

Humanoid robots have the potential to become a part of everyday life as their hardware and software challenges are being solved. In this paper we present a system that gets as input a motion trajectory in the form of motion capture data, and produces a controller that controls a humanoid robot in real-time to achieve a motion trajectory that is similar to the input motion data. The controller expects the input motion data not to be dynamically feasible for the robot and employs a combined controller with corrective components to keep the robot balanced while following the motion. Since the …

The Crinoid Fauna (Echinodermata: Crinoidea) Of Palau, Charles G. Messing

Marine & Environmental Sciences Faculty Articles

Taxonomic revisions and a recent survey using scuba place the number of shallow-water (< 50 m) crinoid species known from Palau at 22. Five are new records: Clarkcomanthus littoralis, Comanthus suavia, Alloeocomatella pectinifera, Oxycomanthus comanthipinna, and O. exilis. A submersible survey (to 310 m) recovered five additional new records, four of which are the first representatives of their families from Palauan waters:Eudiocrinus venustulus (Eudiocrinidae), Glyptometra sp. (Charitometridae), Cosmiometra belsuchel Messing, n. sp. (Thalassometridae), and Porphyrocrinus verrucosus(Phrynocrinidae), the first stalked crinoid recorded from Palau. Two of the three specimens of the latter have regenerating crowns, suggesting that this species may be subject to substantial predation or an …

Laboratory Abrasion Of Crinoid Columnals And The Provenance Of The Chariton Conglomerate, South-Central Iowa, Justin C. Kraber, Steven H. Emerman, Matt R. Bennett, Lyndon R. Hawkins, Jewell E. Moore, Rebekah Ellenwood, Kristine L. Robson, Adam Finken

Journal of the Iowa Academy of Science: JIAS

The Chariton Conglomerate is a quartz limestone conglomerate of Pennsylvanian age found in six exposures in southern Iowa and three exposures in northern Missouri. Distinctive features of the exposures in Iowa include quartz granules and rounded crinoid columnals. The objective of this study was to determine whether the quartz clasts could have originated in the crystalline rocks of Minnesota or Wisconsin. The average paleocurrent direction measured in interbedded sandstones was 178° (S.D. = 35 °). The average roundness of 75 crinoid columnals extracted from four exposures in Iowa was 30% (S.D. = 14%), defined as

roundness(%) = (D-d)/D x 100, …

An Ozone-Modified Refractive Index For Vertically Propagating Planetary Waves, Terrence R. Nathan, Eugene C. Cordero

Eugene C. Cordero

[1] An ozone-modified refractive index (OMRI) is derived for vertically propagating planetary waves using a mechanistic model that couples quasigeostrophic potential vorticity and ozone volume mixing ratio. The OMRI clarifies how wave-induced heating due to ozone photochemistry, ozone transport, and Newtonian cooling (NC) combine to affect wave propagation, attenuation, and drag on the zonal mean flow. In the photochemically controlled upper stratosphere, the wave-induced ozone heating (OH) always augments the NC, whereas in the dynamically controlled lower stratosphere, the wave-induced OH may augment or reduce the NC depending on the detailed nature of the wave vertical structure and zonal mean …

Algorithm Refinement For Fluctuating Hydrodynamics, Alejandro Garcia, Sarah Williams, John B. Bell

Alejandro Garcia

This paper introduces an adaptive mesh and algorithm refinement method for fluctuating hydrodynamics. This particle-continuum hybrid simulates the dynamics of a compressible fluid with thermal fluctuations. The particle algorithm is direct simulation Monte Carlo (DSMC), a molecular-level scheme based on the Boltzmann equation. The continuum algorithm is based on the Landau–Lifshitz Navier–Stokes (LLNS) equations, which incorporate thermal fluctuations into macroscopic hydrodynamics by using stochastic fluxes. It uses a recently developed solver for the LLNS equations based on third-order Runge–Kutta. We present numerical tests of systems in and out of equilibrium, including time-dependent systems, and demonstrate dynamic adaptive refinement by the …

The Pn.S Elliptical Galaxy Survey: Data Reduction, Planetary Nebula Catalog, And Basic Dynamics For Ngc 3379, N. G. Douglas, N. R. Napolitano, Aaron J. Romanowsky, L. Coccato, K. Kuijken, M. R. Merrifield, M. Arnaboldi, O. Gerhard, K. C. Freeman, H. R. Merrett, E. Noordermeer, M. Capaccioli

Aaron J. Romanowsky

We present results from Planetary Nebula Spectrograph (PN.S) observations of the elliptical galaxy NGC 3379 and a description of the data reduction pipeline. We detected 214 planetary nebulae, of which 191 are ascribed to NGC 3379 and 23 to the companion galaxy NGC 3384. Comparison with data from the literature shows that the PN.S velocities have an internal error of lesssim20 km s-1 and a possible offset of similar magnitude. We present the results of kinematic modeling and show that the PN kinematics is consistent with absorption-line data in the region where they overlap. The resulting combined kinematic data set, …

Biogeography And The Cambrian Radiation Of Arachnomorph Arthropods, Jonathan R. Hendricks, Bruce S. Lieberman

Jonathan R. Hendricks

Biogeographic patterns in primarily Cambrian arachnomorph taxa are investigated using a recently constructed phylogenetic hypothesis in order to explore the biogeographic context of the Cambrian radiation. A modified version of Brooks Parsimony Analysis is employed to elucidate patterns of vicariance and geodispersal in taxa from six regions (Laurentia, Baltica, Siberia, Australia, Africa and China). Well resolved vicariance and geodispersal trees are very similar and reconstruct Laurentia and China as sister areas. This close area relationship between Laurentia and China provides extensive evidence for congruent vicariance and range expansion in Cambrian arachnomorphs, while data from trilobites do not show this pattern. …

Numerical Methods For The Stochastic Landau-Lifshitz Navier-Stokes Equations, Alejandro Garcia, John B. Bell, Sarah Williams

Alejandro Garcia

The Landau-Lifshitz Navier-Stokes (LLNS) equations incorporate thermal fluctuations into macroscopic hydrodynamics by using stochastic fluxes. This paper examines explicit Eulerian discretizations of the full LLNS equations. Several computational fluid dynamics approaches are considered (including MacCormack’s two-step Lax-Wendroff scheme and the piecewise parabolic method) and are found to give good results for the variance of momentum fluctuations. However, neither of these schemes accurately reproduces the fluctuations in energy or density. We introduce a conservative centered scheme with a third-order Runge-Kutta temporal integrator that does accurately produce fluctuations in density, energy, and momentum. A variety of numerical tests, including the random walk …

The Star Pile In Abell 545, R. Salinas, T. Richtler, M. J. West, Aaron J. Romanowsky, Y. Schuberth

Aaron J. Romanowsky

Context.Struble (1988, ApJ, 330, L25) found what appeared to be a cD halo without cD galaxy in the center of the galaxy cluster Abell 545. This remarkable feature has been passed almost unnoticed for nearly twenty years. Aims.Our goal is to review Struble's claim by providing a first (preliminary) photometric and spectroscopic analysis of this "star pile". Methods.Based on archival VLT-images and long-slit spectra obtained with Gemini-GMOS, we describe the photometric structure and measure the redshift of the star pile and of the central galaxy. Results.The star pile is indeed associated with Abell 545. Its velocity is higher by about …

Hydrophobic, Organically-Modified Silica Gels Enhance The Structure Of Encapsulated Apomyoglobin, Daryl K. Eggers, V. A. Rocha

Daryl K. Eggers

Insertion of hydrophobic groups in a silica matrix, by addition of propyl- or trifluoropropyltrimethoxysilane, leads to a surprising increase in the helical content of apomyoglobin following encapsulation by the sol–gel technique

Towards Collaborative Service Level Agreement Negotiation, Qiang He, Jun Yan, Yun Yang, Ryszard Kowalczyk, Hai Jin

Faculty of Informatics - Papers (Archive)

A critical issue in the Service Level Agreement management for service composition is to control the relationship between the composite service and the component services in the negotiation. However, existing approaches are inefficient. This paper presents a novel agent-based collaborative approach to address this problem. We introduce a negotiation protocol, under which the agents on the service providers’ side collaborate by exchanging information with each other to gain global knowledge of the negotiation. The collaboration can facilitate the progress of the negotiation. We also discuss the corresponding impact on the decision making strategies.

Newtonian Flow With Nonlinear Navier Boundary Condition, James M. Hill, Miccal T. Matthews

Faculty of Informatics - Papers (Archive)

The generalized nonlinear Navier boundary condition advocated by Thompson and Troian in the journal Nature, and motivated from molecular dynamical simulations, is applied to the conventional continuum mechanical description of fluid flow for three simple pressure-driven flows through a pipe, a channel and an annulus, with a view to examining possible non-uniqueness arising from the nonlinear nature of the boundary condition. For the pipe and the channel it is shown that the results with the nonlinear Navier boundary condition may be obtained from a pseudo linear Navier boundary condition but with a modified slip length. For the annulus, two sets …

Practical Compact E-Cash, Man Ho Au, Willy Susilo, Yi Mu

Faculty of Informatics - Papers (Archive)

Compact e-cash schemes allow a user to withdraw a wallet containing k coins in a single operation, each of which the user can spend unlinkably. One big open problem for compact e-cash is to allow multiple denominations of coins to be spent efficiently without executing the spend protocol a number of times. In this paper, we give a (partial) solution to this open problem by introducing two additional protocols, namely, compact spending and batch spending. Compact spending allows spending all the k coins in one operation while batch spending allows spending any number of coins in the wallet in a …

A Comparative Study Of The Direct Boundary Element Method And The Dual Reciprocity Boundary Element Method In Solving The Helmholtz Equation, Song-Ping Zhu, Yinglong Zhang

Faculty of Informatics - Papers (Archive)

In this paper, we compare the direct boundary element method (BEM) and the dual reciprocity boundary element method (DRBEM) for solving the direct interior Helmholtz problem, in terms of their numerical accuracy and efficiency, as well as their applicability and reliability in the frequency domain. For BEM formulation, there are two possible choices for fundamental solutions, which can lead to quite different conclusions in terms of their reliability in the frequency domain. For DRBEM formulation, it is shown that although the DBREM can correctly predict eigenfrequencies even for higher modes, it fails to yield a reasonably accurate numerical solution for …

Saidi Minimization Of A Remote Distribution Feeder, Kai Zou, Wickramaarachchi W. Keerthipala, Sarath Perera

Faculty of Informatics - Papers (Archive)

Distribution system reliability assessment is an important part of distribution system operation and planning. This paper presents some approaches taken to minimize the SAIDI (System Average Interruption Duration Index) for a remote distribution feeder in an 11kV distribution system. Resulting from unavailability of alternative backup supplies from the other adjacent feeders, distributed generators (DG) can be used as backup supplies in this case. Coordinating distribution automation (DA) system with DGs, the restoration area can be made larger and the outage time can be shorter, consequently, the distribution system reliability can be improved significantly. In this paper, factors affecting SAIDI are …

A Numerical Model For Multiphase Flow Based On The Gmpps Formulation, Part I Kinematics, Song-Ping Zhu, Frank Bierbrauer

Faculty of Informatics - Papers (Archive)

The CFD modeling of two dimensional multiphase ows is a useful tool in industry, although accurate modeling itself remains a difficult task. One of the difficulties is to track the complicated topological deformations of the interfaces between di erent phases. This paper describes a marker-particle method designed to track fluid interfaces for fluid ows of at least three phases. The interface-tracking scheme presented in this paper is the first part of a series of papers presenting our complete model based on a one-field Godunov marker-particle projection scheme (GMPPS). In this part, we shall focus on the presentation of the interface-tracking …

Application Of Semistructured Data Model To The Implementation Of Semantic Content-Based Video Retrieval System, Lilac A. E. Al-Safadi, Janusz R. Getta

Faculty of Informatics - Papers (Archive)

Semantic indexing of a video document is a process that performs the identification of elementary and complex semantic units in the indexed document in order to create a semantic index defined as a mapping of semantic units into the sequences of video frames. Semantic content-based video retrieval system is a software system that uses a semantic index built over a collection of video documents to retrieve the sequences of video frames that satisfy the given conditions. This work introduces a new multilevel view of data for the semantic content-based video retrieval systems. At the topmost level, we define an abstract …

Emotional States Control For On-Line Game Avatars, Ce Zhan, Wanqing Li, Farzad Safaei, Philip Ogunbona

Faculty of Informatics - Papers (Archive)

Although detailed animation has already been achieved in a number of Multi-player On-line Games (MOGs), players have to use text commands to control emotional states of avatars. Some systems have been proposed to implement a real-time automatic system facial expression recognition of players. Such systems can then be used to control avatars emotional states by driving the MOG's "animation engine" instead of text commands. Some of the challenges of such systems is the ability to detect and recognize facial components from low spatial resolution face images. In this paper a system based on an improved face detection method of Viola …

Nursing Information Systems: Applying Usability Testing To Assess The Training Needs For Nursing Students, Yiyu Qiu, Ping Yu

Faculty of Informatics - Papers (Archive)

Objective: In order to ensure the successful implementation of a nursing information system (NIS), nurses and nursing students must be adequately trained. In order to do this effectively, it is essential to understand their training needs. This study focuses on the training needs of nursing students in particular through the identification of the usage problems they encounter. Usability testing, which involves observing users' interaction with an NIS, overcomes the deficiencies of traditional approaches of training needs analysis such as interview and survey. The study applied usability test to assess training needs of nursing students to learn to use a specific …

Development Of A Specialist Medical Vocabulary For Radiation Oncology, Andrew Alexis Miller, Ping Yu

Faculty of Informatics - Papers (Archive)

Controlled medical terminologies that have been developed to describe terms utilized in the field of Radiation Oncology, include SNOMED-CT and DICOM-RT. However, a literature review has failed to provide evidence that the coverage and the level of granularity of these nomenclatures have satisfied the needs of radiation oncologists. Indeed most investigations conclude that the coverage is generally unsatisfactory. Fur-thermore, there is no evidence that an objective specification of the specialist medical terms used in Radiation Oncology has been developed. We report the development of a Specialist Medical Vocabu-lary for Radiation Oncology using an objective and systematic method of discovery of …

New Method Vulnerability Assessment Of Power System, Ahmed M. Haidar, Azah Mohamed, Aini Hussain

Faculty of Informatics - Papers (Archive)

Vulnerability assessment in power systems is to determine a power system`s ability to continue to provide service in case of an unforeseen catastrophic contingency. It combines information on the level of system security as well as information on a wide range of scenarios, events and contingencies. To assess the level of system strength or weakness relative to the occurrence of an undesired event, a quantitative measure based on vulnerability index is often considered. In this study, a new vulnerability assessment method is proposed based on total power system loss which considers power generation loss due to generation outage, power line …

Towards An Integrated Model Of Enterprise Systems, Grace A. Kennedy, C E. Siemieniuch, M A. Sinclair

SMART Infrastructure Facility - Papers

An enterprise system consists of a number of components or building blocks. It is common to use views or models of the enterprise that contain a selection of these components (dependent on the intended usage of the model). The premise is that if these views are considered systems in their own right then the total enterprise system is actually a system‐of‐systems. Difficulty arises however when the boundaries between the systems overlap ‐ it is therefore necessary to have an integrated model of the total enterprise that can cope with these overlaps and hence interactions between the systems. Within this paper …

Air-Drying Of Banana: Influence Of Experimental Parameters, Slab Thickness, Banana Maturity And Harvesting Season, Minh-Hue Nguyen, William E. Price

Faculty of Science - Papers (Archive)

Air-drying of banana slabs has been investigated and the influence of experimental parameters such as temperature, relative humidity and slab thickness has been studied. This was in part re-investigated because of inconsistencies in previous studies, particularly in relation to derived water diffusion coefficients. In addition, it is shown that harvest season and hence initial moisture content has a very marked influence on the drying kinetics. By contrast banana maturity (ripeness) has little influence on the kinetics despite there being significant differences in morphology and chemical composition between green and ripe bananas. The effect of these two variables on the drying …

The Importance Of Slime: Does Living In A Community Matrix Save Algal Cells From The Toxic Effects Of Copper?, Jacqueline Levy, Dianne F. Jolley, Jenny L. Stauber

Faculty of Science - Papers (Archive)

Microscopic algae are often used to assess the toxic effects of chemicals to the environment. They are good indicators of ecosystem health because they form the basis of the aquatic food chain and many algal species are sensitive to metals, like copper, at concentrations which occur naturally in the environment. Most toxicity tests with algae use planktonic species, that is, alga that live in the water as free-living species. To date, little research has been done on the toxicity of metals to attached algal species living in a community matrix known as biofilms, because of the difficulties in quantifying changes …