Physical Sciences and Mathematics Commons^™

Squeak By Example, Andrew P. Black, Stéphane Ducasse, Oscar Nierstrasz, Damien Pollet, Damien Cassou, Marcus Denker

Computer Science Faculty Publications and Presentations

Squeak is a modern open-source development environment for the classic Smalltalk-80 programming language. This book, intended for both students and developers, will guide you gently through the language and tools by means of a series of examples and exercises.

Additional material is available from the book's web page at SqueakByExample.org.

Climate Change And Submerged Aquatic Vegetation In Virginia, Kenneth A. Moore, Robert J. Orth, Virginia Institute Of Marine Science. Initiative For Coastal Climate Change Research

Reports

VIMS climate change white paper: Climate change and submerged aquatic vegetation in Virginia

Vanishing And Emerging Ecosystems Of Coastal Virginia : Climate Change Impacts And Adaptation, Emmett J. Duffy, Virginia Institute Of Marine Science. Initiative For Coastal Climate Change Research

Reports

VIMS climate change white papers: Vanishing and emerging ecosystems of coastal Virginia : climate change impacts and adaptation

Climate Change And Aquatic Animal Health In Virginia : Effects And Responses, Wolfgang K. Vogelbein, Eugene M. Burreson, Ryan Carnegie, Jeffrey D. Shields, Virginia Institute Of Marine Science. Initiative For Coastal Climate Change Reseach

Reports

Climate change, with concomitant increases in sea level, temperature, greenhouse gases and alterations in precipitation, is a major environmental challenge for the future management of Virginia’s valuable marine resources.

Computing Medoids In Large Spatial Datasets, Kyriakos Mouratidis, Dimitris Papadias, Spiros Papadimitriou

Research Collection School Of Computing and Information Systems

In this chapter, we consider a class of queries that arise in spatial decision making and resource allocation applications. Assume that a company wants to open a number of warehouses in a city. Let P be the set of residential blocks in the city. P represents customer locations to be potentially served by the company. At the same time, P also comprises the candidate warehouse locations because the warehouses themselves must be opened in some residential blocks.

Efficient Valid Scope Computation For Location-Dependent Spatial Queries In Mobile And Wireless Environments, Ken C. K. Lee, Wang-Chien Lee, Hong Va Leong, Brandon Unger, Baihua Zheng

Research Collection School Of Computing and Information Systems

In mobile and wireless environments, mobile clients can access information with respect to their locations by submitting Location-Dependent Spatial Queries (LDSQs) to Location-Based Service (LBS) servers. Owing to scarce wireless channel bandwidth and limited client battery life, frequent LDSQ submission from clients must be avoided. Observing that LDSQs issued from similar client positions would normally return the same results, we explore the idea of valid scope, that represents a spatial area in which a set of LDSQs will retrieve exactly the same query results. With a valid scope derived and an LDSQ result cached at the client side, a client …

Offering Rss Feeds: Does It Help To Gain Competitive Advantage?, Dan Ma

Research Collection School Of Computing and Information Systems

Nowadays, many Websites have adopted the really simple syndication (RSS) technology to deliver online content to visitors. In this paper, I build an analytical model to examine how the offering of RSS feeds impact the number of visitors, total traffic load, and profit of Websites in a competitive setting. I show that although RSS can always attract more visitors, it may reduce the Website's profit. Interestingly, in a competitive market there are cases that the RSS feeds hurt the offering Website but benefit the competing Website instead. The conditions under which these will happen are derived. I also study the …

Partially Materialized Digest Scheme: An Efficient Verification Method For Outsourced Databases, Kyriakos Mouratidis, Dimitris Sacharidis, Hwee Hwa Pang

Research Collection School Of Computing and Information Systems

In the outsourced database model, a data owner publishes her database through a third-party server; i.e., the server hosts the data and answers user queries on behalf of the owner. Since the server may not be trusted, or may be compromised, users need a means to verify that answers received are both authentic and complete, i.e., that the returned data have not been tampered with, and that no qualifying results have been omitted. We propose a result verification approach for one-dimensional queries, called Partially Materialized Digest scheme (PMD), that applies to both static and dynamic databases. PMD uses separate indexes …

A Novel Ep Approach For Multi-Area Economic Dispatch With Multiple Fuel Options, P. S. Manoharan, P. S. Kannan, V. Ramanathan

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a novel approach to multi-area economic dispatch problems with multiple fuel options using a hybrid evolutionary programming method. The objective is to minimize the operation cost of the entire system while satisfying the tie line constraints. In this paper, EP-LMO (Evolutionary Programming with Levenberg-Marquardt Optimization) technique is proposed to solve multi-area economic dispatch problems with multiple fuel options. The EP-LMO is developed in such a way that a simple evolutionary programming (EP) is applied as a base level search to find the direction of the optimal global region. And Levenberg-Marquardt Optimization (LMO) method is used as a …

Accurate Prediction Of Crosstalk For Rc Interconnects, Selahatti̇n Sayil, Merlyn Rudrapati

Turkish Journal of Electrical Engineering and Computer Sciences

This work proposes an accurate crosstalk noise estimation method in the presence of multiple RC lines for use in design automation tools. The method correctly models the loading effects of non switching aggressors and aggressor tree branches using resistive shielding effect and realistic exponential input waveform. Noise peak and width expressions derived show very good results in comparison to HSPICE results. Results show that average error for noise peak is 4.1% and for the width is 6.8% while allowing for very fast analysis.

Softcomputing Identification Techniques Of Asynchronous Machine Parameters: Evolutionary Strategy And Chemotaxis Algorithm, Nouri Benaïdja

Turkish Journal of Electrical Engineering and Computer Sciences

Softcomputing techniques are receiving attention as optimisation techniques for many industrial applications. Although these techniques eliminate the need for derivatives computation, they require much work to adjust their parameters at the stage of research and development. Issues such as speed, stability, and parameters convergence remain much to be investigated. This paper discusses the application of the method of reference model to determine parameters of asynchronous machines using two optimisation techniques. Softcomputing techniques used in this paper are evolutionary strategy and the chemotaxis algorithm. Identification results using the two techniques are presented and compared with respect to the conventional simplex technique …

Analytical Regularization Method For Electromagnetic Wave Diffraction By Axially Symmetrical Thin Annular Strips, Fati̇h Di̇kmen, Yury Alexanderovich Tuchkin

Turkish Journal of Electrical Engineering and Computer Sciences

A new mathematically rigorous and numerically efficient method based on the combination of Orthogonal Polynomials Method, and Analytical Regularization Method, for electromagnetic wave diffraction by a model structure for various antennae such as Fresnel zone plates is proposed. It can be used as validation tool for the other (more general or less accurate) numerical methods and physical approaches. The initial boundary value problem is equivalently reduced to the infinite system of the linear algebraic equations of the second kind, i.e. to an equation of the type (I+H) x=b in the space l_2 with compact operator H. This equation can be …

Pca Based Protection Algorithm For Transformer Internal Faults, Erdal Kiliç, Okan Özgönenel, Ömer Usta, Dave Thomas

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper a new protection scheme is introduced to detect and identify transformer winding faults. The new approach is based on artificial neural networks (ANNs) using radial basis functions (RBFs) and the principal component analysis (PCA). The nonlinear system's input and output data is manipulated without considering any model of the system. This approach is used to detect and identify internal short circuit faults of a three phase custom built transformer. The suggested technique is also able to distinguish between the fault and magnetizing inrush current. The test studies carried out shows that the proposed method leads to satisfactory …

Cdm Based Controller Design For Nonlinear Heat Exchanger Process, Erkan İmal

Turkish Journal of Electrical Engineering and Computer Sciences

Most processes are nonlinear, and their control is a difficult yet important problem. The heat exchanger is an example onesuch nonlinear process. In the present paper, the effect of process nonlinearity on the performance of set point tracking and disturbance rejection in two controller methods is investigated. Initially, afirst order plus dead time (FOPDT) model of the process is obtainedvia a software known as Loop-Pro Trainer. Then, the PI-controller tuning values are computed using the internal model control (IMC) correlations based on truncated (first-order) Taylor series approximation. Next, another controller is designed using the coefficient diagram method (CDM). Finally, the …

Polymorphic Worm Detection Using Strong Token-Pair Signatures, Burak Bayoğlu, İbrahi̇m Soğukpinar

Turkish Journal of Electrical Engineering and Computer Sciences

Malicious software has become a big threat to information systems, which are widely used to store, transfer and process information for many critical assets. Worms are one of the most harmful network-enabled malicious software that can threaten networks and applications. Two main characteristics of worms distinguish them from the well-known virus programs and as a result are much more dangerous than the virus programs. First, they do not need to attach themselves to an existing program. Second, worms do not require end-user interaction to realize the intended attack. Therefore, a large number of victims can be infected in a short …

Construction And Applications Of The Dirichlet-To-Neumann Operator In Transmission Line Modeling, Thomas Demeester, Daniel De Zutter

Turkish Journal of Electrical Engineering and Computer Sciences

The Dirichlet-to-Neumann (DtN) operator is a useful tool in the characterization of interconnect structures. In combination with the Method of Moments, it can be used for the calculation of the per-unit length transmission line parameters of multi-conductor interconnections, or to directly determine the internal impedance of conductors. This paper presents a new and fast calculation method for the DtN boundary operator in the important case of rectangular structures, based on the superposition of parallel-plate waveguide modes. Especially for its non-differential form, some numerical issues need to be addressed. It is further explained how the DtN operator can be determined for …

Weak Penetration And Radiation Through Apertures In Conducting Bodies Of Revolution, Korkut Yeği̇n

Turkish Journal of Electrical Engineering and Computer Sciences

The simplest way to solve for penetration through small apertures in conducting surfaces is to treat the body as a scatterer and determine the interior field as the sum of the incident field and the scattered field contributed by the current induced on the surface of the body. However, it is well known that, if the aperture is very small or if the penetrated field is very weak this method yields very inaccurate results, which, in turn, prohibits proper design of electronic systems, especially for electromagnetic compatibility and interference. Previously, alternative integral equations formulations were proposed to remedy this problem …

Experimantal Characterization And Equivalent Circuit Extraction Of Nanowires For Signal Integrity Applications, Giulio Antonini, Marco Di Clerico, Antonio Orlandi, Vittorio Ricchiuti, Maurizio Passacantando, Sandro Santucci

Turkish Journal of Electrical Engineering and Computer Sciences

This paper illustrates the design steps of a printed circuit board used as test vehicles for the measurement of the electrical properties of carbon nanotube's deposit. The board has been built and used for the measurements. The measured data are post-processed in order to extract the required properties of the only nanotubes. An equivalent circuit is extracted for further use in EDA simulators and the IEEE P1597 Standard is used to compare the results.

Emc Education At The University Of Technology Zurich, Gökhan Apaydin, Ni̇yazi̇ Ari

Turkish Journal of Electrical Engineering and Computer Sciences

This paper illustrates educational issues in electromagnetic compatibility (EMC) engineering in Switzerland and presents the contents of courses and practical materials for EMC education at the University of Technology Zurich. After giving the fundamentals of theoretical part, practical applications have been given to make students and engineers aware of EMC issues and its problems.

Electromagnetic Compatibility Engineering Education: Problems, Challenges And Perspectives, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

Education and training problems and challenges in EMC Engineering are discussed. The necessity of physics-based modeling (theory) and hands-on training (practice) are emphasized. An introductory level EMC lecture and a short course outline are given for modern EMC education.

Two Dimensional Ebg Structures For Multiband Noise Mitigation, Antonio Orlandi, Antonio Ciccomancini

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper a two dimensional (2D) electromagnetic Bandgap (EBG) structure is proposed for multi band noise mitigation in PWR/GND plane pairs. Excellent noise suppression (-60 dB) is achieved in multiple bands within the range 0--8 GHz with a low start frequency. Because of the 2D EBG, no additional metal layer is required. Signal Integrity analysis is also studied by modelling a microstrip to stripline transition (both single ended and differential) and by evaluating insertion loss, TDR as well as eye diagram.

Development Of A Magnetic Field Model And Insertion~Into A Commercial Electromagnetic Simulator, Priscila Fernandez Lopez, Christian Arcambal, Yolanda Vives Gilabert, Abhishek Ramanujan, David Baudry, Anne Louis, Belahcene Mazari

Turkish Journal of Electrical Engineering and Computer Sciences

To take into account~certain ElectroMagnetic Compatibility (EMC) aspects~and especially to evaluate the magnetic fields radiated by electronic components, different radiated emission models have been created. Within IRSEEM, a magnetic field model based on equivalent sources (electric dipoles) placed on a plane has been developed. Thus, this paper presents the modelling procedure that requires~magnetic near-field measurements and matrix inversion methods. Concerning the measurements of the field radiated by the component under test,~a near-field test bench with a loop antenna is used to~quantify the tangential components of the magnetic field in amplitude and phase. Then, these data are used as input to …

Electromagnetic Radiation From Multilayer Printed Circuit Boards: A 3d Fdtd-Based Virtual Emission Predictor, Gonca Çakir, Mustafa Çakir, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

A novel FDTD-based virtual electromagnetic compatibility tool for the prediction of electromagnetic emissions from a multilayer printed circuit board is introduced. Tests are performed with characteristic structures and sample simulation results are presented.

Vlsi-Cell Placement Technique For Architecture Of Field Programmable Gate Array (Fpga) Design, Avnesh Verma, Sunil Dhingra, M. K. Soni

Turkish Journal of Electrical Engineering and Computer Sciences

The Field Programmable Gate Array (FPGA) is an on field programmable device which can be designed for different applications. Various types of software are available for its synthesis. The cell placement depends upon the designing and programming languages used for FPGA. In this paper cell placement technique of FPGA architecture is analyzed for the application of Space Vector Pulse Width Modulation (SVPWM) technique used in speed control of an induction motor. The modulation pulses are produced due to the various components activated and their interconnection in Configurable Logic Blocks (CLBs). Few of its components are so analyzed to find out …

New Esd Standard And Influence On Test Equipment Requirements, Nicholas Wright

Turkish Journal of Electrical Engineering and Computer Sciences

The IEC61000-4 series of standards form a basic framework for the immunity and emissions testing of electrical and electronic equipment. They are the basis for EN standards used to test CE compliance of electrical and electronic products sold within the European Union. After a period of relative stability, changes are being introduced, designed to improve reliable application of the basic standards and ensure that the same results are obtained no matter where the tests are performed. Many changes relate to the calibration procedures for the test equipment. The surge standard, IEC61000-4-5, was revised at Edition 2 to amend impulse performance …

Potential Export Of Unattached Benthic Macroalgae To The Deep Sea Through Wind Driven Langmuir Circulation, H. M. Dierssen, Richard C. Zimmerman, Lisa A. Drake, David J. Burdige

OES Faculty Publications

Carbon export to the deep sea is conventionally attributed to the sinking of open ocean phytoplankton. Here, we report a Langmuir supercell event driven by high winds across the shallow Great Bahama Bank that organized benthic non-attached macroalgae, Colpomenia sp., into visible windrows on the seafloor. Ocean color satellite imagery obtained before and after the windrows revealed a 588 km² patch that rapidly shifted from highly productive macroalgae to bare sand. We assess a number of possible fates for this macroalgae and contend that this event potentially transported negatively buoyant macroalgae to the deep Tongue of the Ocean …

Anthropogenic Osmium In Rain And Snow Reveals Global-Scale Atmospheric Contamination, Cynthia Chen, Peter N. Sedwick, Mukul Sharma

OES Faculty Publications

Osmium is one of the rarer elements in seawater, with typical concentration of ≈10 x 10^-15 g g^-1 ( 5.3 x 10^-14 mol kg^-1. The osmium isotope composition (¹⁸⁷Os/¹⁸⁸Os ratio) of deep oceans is 1.05, reflecting a balance between inputs from continental crust (≈ 1.3) and mantle/cosmic dust (≈ 0.13). Here, we show that the ¹⁸⁷Os/¹⁸⁸Os ratios measured in rain and snow collected around the world range from 0.16 to 0.48, much lower than expected (>1), but similar to the isotope composition of ores (approximate to 0.2) …

Spatial Variation In Otolith Chemistry Of Atlantic Croaker Larvae In The Mid-Atlantic Bight, Jason J. Schaffler, Christian S. Reiss, Cynthia M. Jones

OES Faculty Publications

Larval Atlantic croaker Micropogonias undulatus (1 to 7 mm in standard length) were collected on the east coast of the United States from North Carolina to Delaware during 2000. We defined 3 water-mass boundaries for potential groups of spawning Atlantic croaker using temperature and salinity measured at each sampling station. We tested the hypothesis that distinct otolith chemistries existed among 3 groups of larval Atlantic croaker collected from these water masses using solution-based inductively coupled plasma-mass spectrometry. Multivariate analysis of variance indicated that otolith chemistry differed significantly among water masses. Using a quadratic discriminant function, we were able to correctly …

Synergistic Effects Of Iron And Temperature On Antarctic Phytoplankton And Microzooplankton Assemblages, J. M. Rose, Y. Feng, G. R. Ditullio, R. B. Dunbar, C. E. Hare, P. A. Lee, M. Lohan, M. Long, W. O. Smith Jr., B. Sohst, S. Tozzi, Y. Zhang, D. A. Hutchins

OES Faculty Publications

Iron availability and temperature are important limiting factors for the biota in many areas of the world ocean, and both have been predicted to change in future climate scenarios. However, the impacts of combined changes in these two key factors on microbial trophic dynamics and nutrient cycling are unknown. We examined the relative effects of iron addition (+1 nM) and increased temperature (+4° C) on plankton assemblages of the Ross Sea, Antarctica, a region characterized by annual algal blooms and an active microbial community. Increased iron and temperature individually had consistently significant but relatively minor positive effects on total phytoplankton …

A Robust, Multisite Holocene History Of Drift Ice Off Northern Iceland: Implications For North Atlantic Climate, John T. Andrews, Dennis A. Darby, Dennis Eberle, Anne E. Jennings, Matthias Moros, Astrid Ogilvie

OES Faculty Publications

An important indicator of Holocene climate change is provided by evidence for variations in the extent of drift ice. A proxy for drift ice in Iceland waters is provided by the presence of quartz. Quantitative xray diffraction analysis of the < 2 mm sediment fraction was undertaken on 16 cores from around Iceland. The quartz weight (wt.)% estimates from each core were integrated into 250-yr intervals between −0.05 and 11.7 cal. ka BP. Median quartz wt.% varied between 0.2 and 3.4 and maximum values ranged between 2.8 and 11.8 wt.%. High values were attained in the early Holocene and minimum values were reached 6–7 cal. ka BP. Quartz wt.% then rose steadily during the late Holocene. Our data exhibit no correlation with counts on haematite-stained quartz (HSQ) grains from VM129-191 west of Ireland casting doubt on the ice-transport origin. A pilot study on the provenance of Fe oxide grains in two cores that cover the last 1.3 and 6.1 cal. ka BP indicated a large fraction of the grains between 1 and 6 cal. ka BP were from either Icelandic or presently unsampled sources. However, there was a dramatic increase in Canadian and Russian sources from the Arctic Ocean ~1 cal. ka BP. These data may indicate the beginning of an Arctic Oscillation-like climate mode.