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Articles 5371 - 5400 of 5573
Full-Text Articles in Physical Sciences and Mathematics
Development Of The Maryland Shoreline Inventory Methods And Guidelines For Kent County - Gis Data, Marcia Berman, Harry Berquist, Sharon Killeen, Karinna Nunez, Karen Reay, Tamia Rudnicky, Daniel E. Schatt, David Weiss
Development Of The Maryland Shoreline Inventory Methods And Guidelines For Kent County - Gis Data, Marcia Berman, Harry Berquist, Sharon Killeen, Karinna Nunez, Karen Reay, Tamia Rudnicky, Daniel E. Schatt, David Weiss
Data
The Center for Coastal Resources Management (CCRM) at the Virginia Institute of Marine Science (VIMS) has generated Shoreline Situation Reports (SSRs) for coastal localities in the state of Maryland. This effort compliments a parallel effort in Virginia by the same group. SSRs were developed by VIMS in the 1970s for Virginia and have been the foundation for shoreline management planning in Tidewater Virginia ever since. CCRM has developed new protocols for collecting, disseminating, and reporting data relevant to shoreline management issues using state of the art mapping and remote sensing techniques. New SSRs are being generated on a county by …
Development Of The Maryland Shoreline Inventory Methods And Guidelines For Prince Georges County - Gis Data, Marcia Berman, Harry Berquist, Sharon Killeen, Karinna Nunez, Karen Reay, Tamia Rudnicky, Daniel E. Schatt, David Weiss
Development Of The Maryland Shoreline Inventory Methods And Guidelines For Prince Georges County - Gis Data, Marcia Berman, Harry Berquist, Sharon Killeen, Karinna Nunez, Karen Reay, Tamia Rudnicky, Daniel E. Schatt, David Weiss
Data
The Center for Coastal Resources Management (CCRM) at the Virginia Institute of Marine Science (VIMS) has generated Shoreline Situation Reports (SSRs) for coastal localities in the state of Maryland. This effort compliments a parallel effort in Virginia by the same group. SSRs were developed by VIMS in the 1970s for Virginia and have been the foundation for shoreline management planning in Tidewater Virginia ever since. CCRM has developed new protocols for collecting, disseminating, and reporting data relevant to shoreline management issues using state of the art mapping and remote sensing techniques. New SSRs are being generated on a county by …
Development Of The Maryland Shoreline Inventory Methods And Guidelines For Talbot County - Gis Data, Marcia Berman, Harry B, Sharon Killeen, Karinna Nunez, Karen Reay, Tamia Rudnicky, Daniel Schatt, David Weiss
Development Of The Maryland Shoreline Inventory Methods And Guidelines For Talbot County - Gis Data, Marcia Berman, Harry B, Sharon Killeen, Karinna Nunez, Karen Reay, Tamia Rudnicky, Daniel Schatt, David Weiss
Data
The Center for Coastal Resources Management (CCRM) at the Virginia Institute of Marine Science (VIMS) has generated Shoreline Situation Reports (SSRs) for coastal localities in the state of Maryland. This effort compliments a parallel effort in Virginia by the same group. SSRs were developed by VIMS in the 1970s for Virginia and have been the foundation for shoreline management planning in Tidewater Virginia ever since. CCRM has developed new protocols for collecting, disseminating, and reporting data relevant to shoreline management issues using state of the art mapping and remote sensing techniques. New SSRs are being generated on a county by …
Symptoms Of Gastro-Oesophageal Reflux Disease And The Severity Of Obstructive Sleep Apnoea Syndrome Are Not Related In Sleep Disorders Center Patients, H.-N. Kim, R. D. Vorona, M. P. Winn, M. Doviak, D. A. Johnson, J. Catesby Ware
Symptoms Of Gastro-Oesophageal Reflux Disease And The Severity Of Obstructive Sleep Apnoea Syndrome Are Not Related In Sleep Disorders Center Patients, H.-N. Kim, R. D. Vorona, M. P. Winn, M. Doviak, D. A. Johnson, J. Catesby Ware
Mathematics & Statistics Faculty Publications
Background: Studies suggest obstructive sleep apnea syndrome (OSAS) frequently manifests in patients with gastroesophageal reflux disease (GERD) and that there may be a causal relationship.
Aim: To determine the relationship between OSAS and symptoms of GERD.
Methods: Consecutive patients referred to the Sleep Disorders Center (SDC) 18 years and older with polysomnographically defined OSAS were evaluated prospectively for GERD using a validated symptoms questionnaire. The GERD and OSAS relationship was assessed by 1) determining frequency of GERD in patients with and without OSAS; 2) ascertaining the relationship between OSAS severity categories and presence of GERD; 3) examining GERD score in …
The Convergence Of Difference Boxes, Christopher Kribs, Antonio Behn, Vadim Ponomarenko
The Convergence Of Difference Boxes, Christopher Kribs, Antonio Behn, Vadim Ponomarenko
Mathematics Faculty Publications
We consider an elementary mathematical puzzle known as a "difference box" in terms of a discrete map from R⁴ to R⁴ or , canonically, from a subset of the first R² into itself. We identify the map's unique canonical fixed point and answer more generally the question of how many interactions a given "difference box" takes to reach zero. (The number is finite except for boxes corresponding to the fixed point.)
Minimal Modules Over Valuation Domains, Brendan Goldsmith, P. Zanardo
Minimal Modules Over Valuation Domains, Brendan Goldsmith, P. Zanardo
Articles
Let R be a valuation domain. We say that a torsion-free R-module is minimal if it is isomorphic to all its submodules of finite index. Here, the usual concept of finite index for groups is replaced by the more appropriate (for module theory) definition: a submodule H of the module G is said to be of finite index in G if the quotient G/H is a finitely presented torsion module. We investigate minimality in various settings and show inter alia that over a maximal valuation domain, all torsion-free modules are minimal. Constructions of non-minimal modules are given by utilizing realization …
Conformal Properties And Baecklund Transform For The Associated Camassa-Holm Equation, Rossen Ivanov
Conformal Properties And Baecklund Transform For The Associated Camassa-Holm Equation, Rossen Ivanov
Articles
Integrable equations exhibit interesting conformal properties and can be written in terms of the so-called conformal invariants. The most basic and important example is the KdV equation and the corresponding Schwarz-KdV equation. Other examples, including the Camassa-Holm equation and the associated Camassa-Holm equation are investigated in this paper. It is shown that the B¨acklund transform is related to the conformal properties of these equations. Some particular solutions of the Associated Camassa-Holm Equation are discussed also.
Software Development Project Risk Management: A Literature Review, Kevin Macg. Adams, C. Ariel Pinto
Software Development Project Risk Management: A Literature Review, Kevin Macg. Adams, C. Ariel Pinto
Engineering Management & Systems Engineering Faculty Publications
The rapid and unprecedented growth in software has brought with it some of the most spectacular and costly project failures in modern history. How risk management is presented in the scholarly journals may give insight into the risk management methods and techniques in use on software development projects. This paper provides a glimpse into the risk management methods, methodologies and techniques available to those who are responsible for software development projects by conducting a non-experimental content analysis. The findings reveal that risk management has not received sufficient attention and does not appear to be widely accepted within the software engineering …
U.S. Forest Ownership: Historic And Global Perspective, Lloyd C. Irland
U.S. Forest Ownership: Historic And Global Perspective, Lloyd C. Irland
Maine Policy Review
Mainers once enjoyed the sense that the state’s vast forested lands would forevermore be a feature of the state’s landscape and cultural heritage. However, this sensibility has been threatened by fragmentation and sprawl and rapid changes in ownership. According to Lloyd Irland, Maine is not unique. The U.S. is facing a crisis of sustainability in forests and rural communities. Irland provides a brief history of forest ownership in the U.S. and analyzes some global trends to help to explain this crisis. He suggests Mainers look to experiences elsewhere in the nation and world to come up with a new mix …
Intentional Embodied Agents, Alan Martin, Gregory M.P. O'Hare, Brian R. Duffy, John F. Bradley, Bianca Schoen-Phelan
Intentional Embodied Agents, Alan Martin, Gregory M.P. O'Hare, Brian R. Duffy, John F. Bradley, Bianca Schoen-Phelan
Conference papers
The notion of embodiment within a virtual environment and an intelligent agent could be intimately linked, in order to form a single Agent Chameleon. This paper presents an architecture for achieving this, while allowing agents freedom to chose an embodiment suitable to the task at hand..
Upper Limits From The Ligo And Tama Detectors On The Rate Of Gravitational-Wave Bursts, B. P. Abbott, R. Abbott, W. G. Anderson, Mario C. Diaz, Wm. R. Johnston, Soumya Mohanty, Cristina V. Torres
Upper Limits From The Ligo And Tama Detectors On The Rate Of Gravitational-Wave Bursts, B. P. Abbott, R. Abbott, W. G. Anderson, Mario C. Diaz, Wm. R. Johnston, Soumya Mohanty, Cristina V. Torres
Physics and Astronomy Faculty Publications and Presentations
We report on the first joint search for gravitational waves by the TAMA and LIGO collaborations. We looked for millisecond-duration unmodeled gravitational-wave bursts in 473 hr of coincident data collected during early 2003. No candidate signals were found. We set an upper limit of 0.12 events per day on the rate of detectable gravitational-wave bursts, at 90% confidence level. From software simulations, we estimate that our detector network was sensitive to bursts with root-sum-square strain amplitude above approximately 1–3×10−19 Hz−1/2 in the frequency band 700-2000 Hz. We describe the details of this collaborative search, with particular emphasis on its advantages …
New Standards For Reducing Gravity Data: The North American Gravity Database, William J. Hinze, Carlos Aiken, John Brozena, Bernard Coakley, David Dater, Guy Flanagan, Rene Forsberg, Thomas Hildenbrand, G. Randy Keller, James N. Kellogg, Robert Kucks, Xiong Li, Andre Mainville, Robert Morin, Mark Pilkington, Donald Plouff, Dhananjay Ravat, Daniel Roman, Jamie Urrutia-Fucugauchi, Marc Veronneau, Michael Webring, Daniel Winester
New Standards For Reducing Gravity Data: The North American Gravity Database, William J. Hinze, Carlos Aiken, John Brozena, Bernard Coakley, David Dater, Guy Flanagan, Rene Forsberg, Thomas Hildenbrand, G. Randy Keller, James N. Kellogg, Robert Kucks, Xiong Li, Andre Mainville, Robert Morin, Mark Pilkington, Donald Plouff, Dhananjay Ravat, Daniel Roman, Jamie Urrutia-Fucugauchi, Marc Veronneau, Michael Webring, Daniel Winester
Faculty Publications
The North American gravity database as well as databases from Canada, Mexico, and the United States are being revised to improve their coverage, versatility, and accuracy. An important part of this effort is revising procedures for calculating gravity anomalies, taking into account our enhanced computational power, improved terrain databases and datums, and increased interest in more accurately defining long-wavelength anomaly components. Users of the databases may note minor differences between previous and revised database values as a result of these procedures. Generally, the differences do not impact the interpretation of local anomalies but do improve regional anomaly studies. The most …
Polar Measurements Of Mesospheric Co, Susannah Burrows
Polar Measurements Of Mesospheric Co, Susannah Burrows
Honors Papers
An optically thin layer of carbon monoxide in the Earth's mesosphere results in strong, sharp emission peaks at CO's rotational transition frequencies. The J = 2 → 1 and J = 4 → 3 transitions were observed by the Antarctic Sub-millimeter Telescope / Remote Observatory (AST/RO), located at the Amundsen-Scott South Pole station. Mesospheric wind speeds were calculated from the Doppler shifts in emission spectra, as determined by least-squares fitting.
Rcu Semantics: A First Attempt, Paul E. Mckenney, Jonathan Walpole
Rcu Semantics: A First Attempt, Paul E. Mckenney, Jonathan Walpole
Computer Science Faculty Publications and Presentations
There is not yet a formal statement of RCU (read-copy update) semantics. While this lack has thus far not been an impediment to adoption and use of RCU, it is quite possible that formal semantics would point the way towards tools that automatically validate uses of RCU or that permit RCU algorithms to be automatically generated by a parallel compiler. This paper is a first attempt to supply a formal definition of RCU. Or at least a semi-formal definition: although RCU does not yet wear a tux (though it does run in Linux), at least it might yet wear some …
Locality, Network Control And Anomaly Detection, Jim Binkley
Locality, Network Control And Anomaly Detection, Jim Binkley
Computer Science Faculty Publications and Presentations
Ourmon is a near real-time network monitoring and anomaly detection system that captures packets using port-mirroring on Ethernet switches. It primarily displays data via web graphics using either RRDTOOL stripcharts or via histograms for top talker style graphs. We have developed a theory that network scanning launched primarily by worm programs including TCP and UDP scanners may be caught by monitoring network control data including TCP control packets (SYNS, FINS, RESETS) and ICMP errors, or by monitoring certain carefully chosen metadata such as the flow count itself. In this paper we concentrate on TCP and present a ”flow tuple” focused …
Yorktown Beach 2003-2005, With Hurricane Isabel Impacts, Donna A. Milligan, C. Scott Hardaway Jr., Linda M. Meneghini, George R. Thomas, Christine A. Wilcox
Yorktown Beach 2003-2005, With Hurricane Isabel Impacts, Donna A. Milligan, C. Scott Hardaway Jr., Linda M. Meneghini, George R. Thomas, Christine A. Wilcox
Reports
The Yorktown Public Beach is located on the south side of the York River at Yorktown, Virginia (Figure 1). It is approximately 1,200 feet in length. Historically, the beach was a product of erosion of nearby sandy upland banks and the littoral transport system. Over the years, the beaches along the waterfront began to narrow as the natural sediment supply was depleted by hardening of the updrift shorelines and were easily overwashed in storms and had continually eroded. Since 1978, various projects have taken place along Yorktown’s shoreline in order to abate erosion, provide a recreational beach, and minimize damage …
The Tide Next Time, John D. Boon
The Tide Next Time, John D. Boon
Reports
Will sea level be higher the next time Virginia encounters a hurricane? The most likely answer is ‘yes’. See https://scholarworks.wm.edu/reports/2803 for my article titled The three Faces of Isabel describing the role of changing sea level in shaping the storm tide produced by Hurricane Isabel on 18 September 2003. As explained in that article, a storm tide is the extreme water level that results when storm surge, the short-term change in water level due to the effects of the storm, is superposed on the everyday rise and fall of the astronomical tide that happens to be in place as the …
Ontology-Assisted Mining Of Rdf Documents, Tao Jiang, Ah-Hwee Tan
Ontology-Assisted Mining Of Rdf Documents, Tao Jiang, Ah-Hwee Tan
Research Collection School Of Computing and Information Systems
Resource description framework (RDF) is becoming a popular encoding language for describing and interchanging metadata of web resources. In this paper, we propose an Apriori-based algorithm for mining association rules (AR) from RDF documents. We treat relations (RDF statements) as items in traditional AR mining to mine associations among relations. The algorithm further makes use of a domain ontology to provide generalization of relations. To obtain compact rule sets, we present a generalized pruning method for removing uninteresting rules. We illustrate a potential usage of AR mining on RDF documents for detecting patterns of terrorist activities. Experiments conducted based on …
Robust Temporal Constraint Networks, Hoong Chuin Lau, Thomas Ou, Melvyn Sim
Robust Temporal Constraint Networks, Hoong Chuin Lau, Thomas Ou, Melvyn Sim
Research Collection School Of Computing and Information Systems
In this paper, we propose the Robust Temporal Constraint Network (RTCN) model for simple temporal constraint networks where activity durations are bounded by random variables. The problem is to determine whether such temporal network can be executed with failure probability less than a given 0 ≤ E ≤ 1 for each possible instantiation of the random variables, and if so. how one might find a feasible schedule with each given instantiation. The advantage of our model is that one can vary the value of ∊ to control the level of conservativeness of the solution. We present a computationally tractable and …
Partnering For Perfection: An Economics Perspective On B2b Electronic Market Strategic Alliances, Qizhi Dai, Robert J. Kauffman
Partnering For Perfection: An Economics Perspective On B2b Electronic Market Strategic Alliances, Qizhi Dai, Robert J. Kauffman
Research Collection School Of Computing and Information Systems
New technological innovations have made it possible for new intermediaries to create value in business processes that involve the procurement of manufacturing and services supplies. Associated with these innovations is the emergence of business-to-business (B2B) electronic markets. These act as digital intermediaries that aim to reduce the transaction costs and mitigate the risks inherent in procurement. They improve buyers’ capabilities to search for attractive prices and also serve to increase the liquidity of sellers’ products. In this chapter, the authors explore the evolution of B2B e-market firms in terms of the strategies they employ to “perfect” their value propositions and …
Ultra Wide-Band : State Of The Art; Implementation Of A Performance-Controllable Low-Noise Amplifier, Serigne Dia, Balwant Godora, Frederic Alicalapa, Alain Fabre
Ultra Wide-Band : State Of The Art; Implementation Of A Performance-Controllable Low-Noise Amplifier, Serigne Dia, Balwant Godora, Frederic Alicalapa, Alain Fabre
Turkish Journal of Electrical Engineering and Computer Sciences
Ultra Wide-Band (UWB) transmissions exhibit performances vastly superior to existing wireless systems - superlative data-rate capacity, high security, low cost, low power consumption - and are emerging as the hottest topic of research for upcoming wireless generations. This communication protocol is studied in detail, with mention of the history and estimates for the near future; the present and possible applications are mentioned; the advantages and unresolved issues are detailed; a typical UWB transceiver architecture is studied; the modulation and coding schemes are enumerated; and the possibility of long-range communication is touched upon. Finally, a new performance-controllable low-noise amplifier (LNA) destined …
A Realization Of Sc-Cnn-Based Circuit Using Ftfn, Eni̇s Günay, Esma Uzunhi̇sarcikli, Recai̇ Kiliç, Mustafa Alçi
A Realization Of Sc-Cnn-Based Circuit Using Ftfn, Eni̇s Günay, Esma Uzunhi̇sarcikli, Recai̇ Kiliç, Mustafa Alçi
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a realization of the State Controlled Cellular Neural Network (SC-CNN)-based circuit using Four Terminal Floating Nullor (FTFN) as active element is presented. In this realization, a new version of autonomous Chua's circuit has been considered using FTFN realization of SC-CNN-based circuit. The performance of the proposed SC-CNN-based circuit is demonstrated by PSpice simulations.
Sigma-Delta Voltage To Frequency Converter With Phase Modulation Possibility, Milan Stork
Sigma-Delta Voltage To Frequency Converter With Phase Modulation Possibility, Milan Stork
Turkish Journal of Electrical Engineering and Computer Sciences
Voltage to frequency converter (VFC) is an oscillator whose frequency is linearly proportional to control voltage. There are two common VFC architectures: the current steering multivibrator and the charge-balance VFC. For higher linearity, the charge-balancing method is preferred. The charge balanced VFC may be made in asynchronous or synchronous (clocked) forms. The synchronous charge balanced VFC or "sigma delta" (\Sigma-\Delta) VFC is used when output pulses are synchronized to a clock. The charge balance VFC is more complex, more demanding in its supply voltage and current requirements, and more accurate. It is capable of 16 to18 bit linearity. In this …
An Algorithm For Image Clustering And Compression, Meti̇n Kaya
An Algorithm For Image Clustering And Compression, Meti̇n Kaya
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a new approach to image compression based on fuzzy clustering. This new approach includes pre-filtering, and fuzzy logic image enhancing to reduce undesirable noise effects on segmentation result; separation of image into 4x4 blocks and two dimensional discrete cosine transform; obtaining of peak values of cosine membership functions by combining of performing the zig-zag method with discrete cosine transform coefficients; obtaining of membership values and cluster centroids; and finally, creation of segmented image and compression. After applying the new method on sample images at different number of clusters, better compression ratio, performing time and good validity measure …
Transformer Protection Using The Wavelet Transform, Okan Özgönenel, Güven Önbi̇lgi̇n, Çağri Kocaman
Transformer Protection Using The Wavelet Transform, Okan Özgönenel, Güven Önbi̇lgi̇n, Çağri Kocaman
Turkish Journal of Electrical Engineering and Computer Sciences
This paper introduces a novel approach for power transformer protection algorithm. Power system signals such as current and voltage have traditionally been analysed by the Fast Fourier Transform. This paper aims to prove that the Wavelet Transform is a reliable and computationally efficient tool for distinguishing between the inrush currents and fault currents. The simulated results presented clearly show that the proposed technique for power transformer protection facilitates the accurate discrimination between magnetizing inrush and fault currents in transformer protection.
Soft Computing Methods In Microwave Active Device Modeling, Yavuz Cengi̇z, Fi̇li̇z Güneş, Mehmet Fati̇h Çağlar
Soft Computing Methods In Microwave Active Device Modeling, Yavuz Cengi̇z, Fi̇li̇z Güneş, Mehmet Fati̇h Çağlar
Turkish Journal of Electrical Engineering and Computer Sciences
In this work, the signal and noise behaviors of a microwave transistor within its operation domain (CT,V_{DS}, I_{DS}, f) are modeled by the Artificial Neural Network (ANN) and Fuzzy Logic System (FLS) without using any information on the microwave circuit theory . A worked example is presented where the same data is employed for both models selected from the manufacturer's data sheets. Performances of the FLS and ANN models are compared and conclusions are drawn.
Impacts Of Distributed Generators On The Oscillatory Stability Of Interconnected Power Systems, İstemi̇han Genç, Ömer Usta
Impacts Of Distributed Generators On The Oscillatory Stability Of Interconnected Power Systems, İstemi̇han Genç, Ömer Usta
Turkish Journal of Electrical Engineering and Computer Sciences
Integration of distributed generation is continually and gradually affecting the stability of interconnected power systems. In this paper, the impacts of distributed synchronous generators on oscillatory stability are studied. In various parameter sub-spaces of interest, feasibility regions can be calculated to determine the conditions to sustain the stable operation of an interconnected power system. Through computations of the feasibility boundaries corresponding to Hopf bifurcations of electromechanical oscillatory modes, we determine the operating limits for a stable operation of the system under small and continual disturbances such as predictable changes in loading conditions of generators. Thus, with the case studies given …
Multilayer Capacitor Model Of The Earth's Upper Crust, Berk Üstündağ, Özcan Kalenderli̇, Haluk Eyi̇doğan
Multilayer Capacitor Model Of The Earth's Upper Crust, Berk Üstündağ, Özcan Kalenderli̇, Haluk Eyi̇doğan
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, an equivalent electric circuit model of Earth's upper crust is proposed to explain the behavior of measurement patterns acquired from network of the earthquake forecast project. A multi-layer capacitor model having active components that couples with the monopolar probe close to the surface is used to determine earthquake precursory patterns due to structural changes in time. Equivalent circuit model was developed for a) dilatency process that is assumed to be a stress weakening reason and b) external force source that increases shear stress over the fault until sudden decrement before the earthquake. A data acquisition system consisting …
Fault Tolerant Control With Re-Configuring Sliding-Mode Schemes, Ufuk Demi̇rci̇, Feza Kerestecioğlu
Fault Tolerant Control With Re-Configuring Sliding-Mode Schemes, Ufuk Demi̇rci̇, Feza Kerestecioğlu
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a controller design method for linear MIMO systems is presented which a sliding mode controller is reconfigured in case of system faults. Faults are detected with the residual vector generated from a standard linear observer. Once a fault has been detected the fault distribution matrix can be obtained and used to update the corrective or equivalent control parts of the sliding mode controller. As a result, fault tolerant adaptive controllers keep the system performance within acceptable limits or at least avoids the system to wind-up.
Turbo Codes: The Issue Of Average Union Upper Bound Under Imperfect Channel State Information In Rayleigh Fading Channels, Erhan A. İnce, Syed Amjad Ali
Turbo Codes: The Issue Of Average Union Upper Bound Under Imperfect Channel State Information In Rayleigh Fading Channels, Erhan A. İnce, Syed Amjad Ali
Turkish Journal of Electrical Engineering and Computer Sciences
The potential of turbo codes to demonstrate excellent performance in the region of low signal to noise ratio is now a familiar fact. The idea of turbo codes was first introduced by Berrou and was based on the clever utilization of the existing decoding mechanism of BCJR with a change in the encoder by introducing feedback and an interleaver in the overall scheme. Since then, these powerful forward error correcting codes have attained a significant attention and have either replaced or have become a sturdy candidate for many applications in this era of modern communication systems. So far, a lot …