Dissertations / Theses on the topic 'Area measurement'
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1
McPhail, Diane. "Area : the big cover-up." Thesis, View thesis, 2007. http://handle.uws.edu.au:8081/1959.7/27435.
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The research problem reported in this thesis is an investigation of the teaching and learning of area measurement in the early years of school. Research indicates that children confuse the measurement of area and perimeter and also the use of linear and two-dimensional units of measure. The first phase of the study investigated the knowledge and skills which underpin an understanding of the L x B formula for calculating rectangular area. Those factors were used to plan a teaching program of four lessons for Year 1 and Year 2 children, focusing on: establishing the attribute of area; making, describing and drawing the spatial structure of arrays of repeated informal units to measure areas; and methods of counting to determine the total number of units. The effectiveness of the program was evaluated by implementing the lessons in four classes. Lessons planned from the then current syllabus were implemented in another four classes. Comparison of student learning outcomes from all classes indicated that the research lessons were more effective in assisting children to develop an understanding of a grid pattern or array of repeated informal units. The second phase of this study described the researcher’s investigation, design and trial of teacher professional learning strategies which would assist teachers to adopt successful methods of teaching young children to measure area. Seventeen volunteer teachers in seven school teams participated in one of three models of professional learning, based on varying levels of consultancy support. The models were based on the provision of lesson notes and teaching materials, facilitation of team meetings to discuss the implementation, and the provision of additional time to interview individual children following each lesson. Participation in the project assisted all of the participating teachers to develop their content knowledge and to modify their teacher-centred teaching practices. The key strategies and factors which contributed to this success included ongoing school based professional dialogue and support, the provision of a teaching program which emphasised students’ conceptual development within a sequence of activities, the role played by teacher leaders within each team, opportunities to develop questioning techniques and the motivation and disposition of the participating teachers.ABSTRACT
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McPhail, Diane. "Area the big cover-up /." View thesis, 2007. http://handle.uws.edu.au:8081/1959.7/27435.
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Thesis (Ph.D.)--University of Western Sydney, 2007."A thesis submitted to the University of Western Sydney, College of Arts, School of Education in fulfilment of the requirements for the degree of Doctor of Philosophy." Includes bibliography.
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Freeman, Matthew A. "Multi-area power system state estimation utilizing boundary measurements and phasor measurement units ( PMUs)." Thesis, Texas A&M University, 2006. http://hdl.handle.net/1969.1/4178.
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The objective of this thesis is to prove the validity of a multi-area state estimator and investigate the advantages it provides over a serial state estimator. This is done utilizing the IEEE 118 Bus Test System as a sample system. This thesis investigates the benefits that stem from utilizing a multi-area state estimator instead of a serial state estimator. These benefits are largely in the form of increased accuracy and decreased processing time. First, the theory behind power system state estimation is explained for a simple serial estimator. Then the thesis shows how conventional measurements and newer, more accurate PMU measurements work within the framework of weighted least squares estimation. Next, the multi-area state estimator is examined closely and the additional measurements provided by PMUs are used to increase accuracy and computational efficiency. Finally, the multi-area state estimator is tested for accuracy, its ability to detect bad data, and computation time.
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Jones, Paul. "Electrical measurement of large area substation earth grids." Thesis, Swansea University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367883.
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Huang, Jiarui M. Eng Massachusetts Institute of Technology. "Automatic 3D surface area measurement for vitiligo lesions." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113733.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 62-64).
Vitiligo is a long term skin depigmentation disease that may result in psychological stress. Monitoring changes in vitiligo lesion area allows assessment of treatment efficacy and aids in clinical decision making. Currently existing approaches for vitiligo lesion measurement are either inefficient or inaccurate. Using a RGB-D camera (Kinect) and imaging processing techniques, we develop an automated skin lesion screening system (VLAMS) that can be widely adopted in clinics. VLAMS is tested using clinical medical data. Results show VLAMS can consistently segment target lesion region and accurately measure lesion area of any skin surface.
by Jiarui Huang.
M. Eng.
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Lehmann, Timothy H. "Teaching area measurement and subgoals through problem solving." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/117668/1/Timothy_Lehmann_Thesis.pdf.
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This thesis examined the teaching and learning of area measurement and the subgoals strategy through problem solving. A pedagogical model was developed to show how students' conceptual understanding of a mathematical concept and their strategic competence can develop simultaneously through problem solving.
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Hurtgen, Michaël. "Wide-area state estimation using synchronized phasor measurement units." Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209924.
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State estimation is an important tool for power system monitoring and the present study involves integrating phasor measurement units in the state estimation process. Based on measurements taken throughout the network, the role of a state estimator is to estimate the state variables of the power system while checking that these estimates are consistent with the measurement set. In the case of power system state estimation, the state variables are the voltage phasors at each network bus.\\The classical state estimator currently used is based on SCADA (Supervisory Control and Data Acquisition) measurements. Weaknesses of the SCADA measurement system are the asynchronicity of the measurements, which introduce errors in the state estimation results during dynamic events on the electrical network.\\
Wide-area monitoring systems, consisting of a network of Phasor Measurement Units (PMU) provide synchronized phasor measurements, which give an accurate snapshot of the monitored part of the network at a given time. The objective of this thesis is to integrate PMU measurements in the state estimator. The proposed state estimators use PMU measurements exclusively, or both classical and PMU measurements.\\
State estimation is particularly useful to filter out measurement noise, detect and eliminate bad data. A sensitivity analysis to measurement errors is carried out for a state estimator using only PMU measurements and a classical state estimator. Measurement errors considered are Gaussian noise, systematic errors and asynchronicity errors. Constraints such as zero injection buses are also integrated in the state estimator. Bad data detection and elimination can be done before the state estimation, as in pre-estimation methods, or after, as in post-estimation methods. For pre-estimation methods, consistency tests are used. Another proposed method is validation of classical measurements by PMU measurements. Post-estimation is applied to a measurement set which has asynchronicity errors. Detection of a systematic error on one measurement in the presence of Gaussian noise is also analysed. \\
The state estimation problem can only be solved if the measurements are well distributed over the network and make the network observable. Observability is crucial when trying to solve the state estimation problem. A PMU placement method based on metaheuristics is proposed and compared to an integer programming method. The PMU placement depends on the chosen objective. A given PMU placement can provide full observability or redundancy. The PMU configuration can also take into account the zero injection nodes which further reduce the number of PMUs needed to observe the network. Finally, a method is proposed to determine the order of the PMU placement to gradually extend the observable island. \\
State estimation errors can be caused by erroneous line parameter or bad calibration of the measurement transformers. The problem in both cases is to filter out the measurement noise when estimating the line parameters or calibration coefficients and state variables. The proposed method uses many measurement samples which are all integrated in an augmented state estimator which estimates the voltage phasors and the additional parameters or calibration coefficients.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
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Liu, Di. "Integral Measurement of Atmospheric Particulate Matter (PM)." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5573.
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Atmospheric aerosol particles also known as atmospheric particulate matter or particulate matter (PM) are microscopic particles (solid or liquid) suspended in air, which is one of six air pollutants in US air quality standard. PM is classified as coarse particles with diameters between 2.5 to 10 mm, fine particles with a diameter less than 2.5 mm (PM2.5), and ultrafine particles with the diameter less than 0.1 mm (PM0.1). Epidemiological studies have already showed the adverse health effects (such as asthma, lung cancer and respiratory and cardiovascular disease) resulted from exposure to the fine and ultrafine particles. Monitoring the PM concentration (i.e., either mass or surface area concentration of PM) is critical for the protection of public health and environment and for the regulatory control. Various PM sensors are now available in market. A majority of these PM sensors are optical sensors, whose readouts are highly depended on the physical property and composition of PM. Several PM monitors based on the measurement principle of electrical charging are also available. However, the empirical calibration of the readout of these electrical PM monitors via the use of standard dust particles makes it difficult to obtain the true mass concentration of PM when PM size distribution is different from that of standard dust.
The overall objective of this dissertation is to advance our scientific knowledge on the performance of cost-effective PM monitors for measuring either mass or surface area concentration of fine and ultrafine PM. This thesis includes two parts: (1) is on the evaluation of existing PM sensor for PM mass concentration measurement; (2) is on the development of new PM monitor for PM surface area concentration measurement. For the first part of this dissertation, four low-cost optical sensors, one Personal Dust Monitor (PDM) and DustrakTM were experimentally evaluated. Particles in the size distribution having different mean size, standard deviation value and material were used as test aerosol particles. The readouts of these low-cost and portable sensors are compared to that of a standard TEOM (Tapered Element Oscillation Microbalance). For the second part of this dissertation, a new electrical PM monitor, consisting of a corona-based aerosol charger, a precipitator and high sensitive current meter, has been proposed for measuring surface area concentration of fine and ultrafine PM. Particles are electrically charged upon entering an electrical PM monitor. Instead of using Faraday cage and current meter to measure the charges carried by particles in existed electrical PM sensors, the new PM monitor measures the current carried by particles deposited directly on the wall of the precipitator. A thorough evaluation has been carried out to evaluate the fundamental performance of this new PM monitor. In addition, small cyclones (i.e., quadru-inlet and tapered-body cyclones) were also evaluated as the size-selective inlet of these PM sensors/monitors to minimize the potential interface from the presence of PM with large sizes in the air. The small quadru-inlet cyclone is to resolve the issue of directional sampling; and the tapered-body cyclones is to reduce the cyclone pressure drop while having small cyclone cutoff particle size. Each cyclone has been evaluated via the measurement of particle penetration curve and pressure drop. Semi-empirical models have been obtained for the prediction of cyclone performance.
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Antoine, Olivier. "Wide area measurement-based approach for assessing the power flow influence on inter-area oscillations." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209368.
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Power systems have been historically designed at a time when the production wascentralized and the electricity had to be transmitted to the loads from the closest power
plant. Nowadays, there is an increasing integration of decentralized and intermittent pro-
duction. Moreover, the energy market coupling has enabled the transfer of electric power
for economical purposes. Also, former isolated power systems are now interconnected for
reliability and financial reasons.
All of these changes make difficult to predict the future behavior of the grid. Studies
are done in order to plan for the future needs of the system. However, building new in-
frastructures takes time and it is expected that these needs will not be completely fulfilled
in all the parts of the grid. Therefore, transmission of active power could be limited by
the existing infrastructure. For example, the presence of inter-area oscillations is often
the limiting factor when a high active power is transmitted on a long transmission line
between two groups of generators. Since higher levels of active power are exchanged on
longer distances, problems of inter-area oscillations may arise in power systems previously
not affected by this phenomenon.
In this work, a measurement-based approach, able to predict in the short-term the
future behavior of oscillations, is presented. This approach is complementary to the
long-term planning of the grid.
The mandatory first step towards a measurement-based approach is to have the ability
to extract useful information among a huge quantity of data. To face this issue, some
comparisons of data mining algorithms are performed. The proposed method combines
two decision tree algorithms to obtain both prediction accuracy and comprehensibility.
The second required step for building a measurement-based model is to take into
account the limitations of the measurements. Two types of wide area measurements are
used, synchronized measurements from PMUs and traditional unsynchronized data from
the SCADA/EMS system. Oscillation monitoring using PMUs is especially of interest
and an approach is presented to post-process damping estimates. This post-processing
method consists in a noise reduction technique followed by a damping change detection
algorithm.
Finally, the method, combining these two steps, is implemented to analyze the Con-
tinental European grid. This implementation takes place in the context of the European
project Twenties. The results, using several months of measurements, are described in
detail before being discussed.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
10
McKean, Greg. "An investigation into year seven students' knowledge and understanding of area." Thesis, Queensland University of Technology, 1989. https://eprints.qut.edu.au/36697/1/36697_McKean_1989.pdf.
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A review of area teaching sequences indicated general agreement about
what concepts need to be taught, the sequence in which to develop
these concepts and the sorts of teaching strategj es that need to be
employed.
Existing research seemed to indicate a disparity between recommended
teaching practices and what is actually happening in classrooms,
however, actual research into children's understanding of key area
concepts and information about the process and strategies children
employ in solving area problems was limited .
This s tudy was designed to address this deficiency . The study was
designed ito provide i nsights into upper primary students' knowledge
and understanding of important area concepts. The study had three
areas of focus; pre-formula area concepts, the formula for the area of
a rectangle and the formulas A = S x S and A = b x h -t 2, both of
which can be derived from the formula for the area of a rectangle.
Nine area tasks were developed . The tasks were designed to give
students the opportunity to display behaviour from which mental
mechanisms can be inferred. The tasks formed the basis of a clinical
interview . All students were initially presented with the same
tasks, however, subsequent questioning varied according to the 11Jay
children responded to the initial questions. The interviews were
conducted using twenty year seven students. The i nterviews were of
approximately twenty mi nutes duration.
t ape recorded for later analysis. The information collected from the i nterviews indicated that
child1ren' s understandi ng varied quite significantly from one concept
to another . On the whole, children's understanding of pre-formula
area concepts was quite good . The one aspect of pre-formula area
concepts that caused difficulties was s tandard uni ts. Chi.ldren 's
knowledge and understanding of standard units was noticeably
inadequate.
A majority of students had a sound understanding of the formulas for
finding the areas of rectangles , squares and triangles . Most
students recognized that the formula A = b x h + 2 was similar to
halving the area of a rectangle; however, students were initially
reluctant to accept that the rules A = 1 x b and A = S x S were
relatEid.
The study identified several common gaps and misconceptions . It was
doubtful whether these gaps and misconceptions could be attributed to
students' inability to come to terms with overly difficult ma t e r ial.
It seHmed more likely that the gaps and misconceptions were linked
with a t eaching sequence that tends to rush i nto formulas , teachers'
inability to identify and diagnose students' errors and
misconceptions, students needlessly fragmenting and compartmentalizing
similar i deas and students having only limited opportunities in which
to test, extend and apply their knowledge and understanding
meaningfully.
The study concluded with a list of recommendations that were i ntended
to help overcome some of the gaps and misconceptions that this study
identified .
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Petriccione, Gregory James. "Design and integration of a large area warpage measurement system." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/18207.
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Khatib, Abdel Rahman Amin. "Internet-based Wide Area Measurement Applications in Deregulated Power Systems." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/28579.
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Since the deregulation of power systems was started in 1989 in the UK, many countries have been motivated to undergo deregulation. The United State started deregulation in the energy sector in California back in 1996. Since that time many other states have also started the deregulation procedures in different utilities. Most of the deregulation market in the United States now is in the wholesale market area, however, the retail market is still undergoing changes.
Deregulation has many impacts on power system network operation and control. The number of power transactions among the utilities has increased and many Independent Power Producers (IPPs) now have a rich market for competition especially in the green power market. The Federal Energy Regulatory Commission (FERC) called upon utilities to develop the Regional Transmission Organization (RTO). The RTO is a step toward the national transmission grid. RTO is an independent entity that will operate the transmission system in a large region. The main goal of forming RTOs is to increase the operation efficiency of the power network under the impact of the deregulated market.
The objective of this work is to study Internet based Wide Area Information Sharing (WAIS) applications in the deregulated power system. The study is the first step toward building a national transmission grid picture using information sharing among utilities. Two main topics are covered as applications for the WAIS in the deregulated power system, state estimation and Total Transfer Capability (TTC) calculations. As a first step for building this national transmission grid picture, WAIS and the level of information sharing of the state estimation calculations have been discussed. WAIS impacts to the TTC calculations are also covered. A new technique to update the TTC using on line measurements based on WAIS created by sharing state estimation is presented.Ph. D.
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Tania, Mutmainna. "Wide Area Measurement Applications for Improvement of Power System Protection." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/19241.
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The increasing demand for electricity over the last few decades has not been followed by adequate growth in electric infrastructure. As a result, the reliability and safety of the electric grids are facing tremendously growing pressure. Large blackouts in the recent past indicate that sustaining system reliability and integrity turns out to be more and more difficult due to reduced transmission capacity margins and increased stress on the system. Due to the heavy loading conditions that occur when the system is under stress, the protection systems are susceptible to mis-operation. It is under such severe situations that the network cannot afford to lose its critical elements like the main generation units and transmission corridors.In addition to the slow but steady variations in the network structure over a long term, the grid also experiences drastic changes during the occurrence of a disturbance. One of the main reasons why protection relays mis-operate is due to the inability of the relays to adjust to the evolving network scenario. Such failures greatly compound the severity of the disturbance, while diminishing network integrity leading to catastrophic system-wide outages. With the advancement of Wide Area Measurement Systems (WAMS), it is now possible to redesign network protection schemes to make them more adaptive and thus improve the security of the system.
Often flagged for exacerbating the events leading to a blackout, the back-up distance protection relay scheme for transmission line protection and the loss-of-field relay scheme for generator unit protection can be greatly improved from an adaptability-oriented redesign. Protection schemes in general would benefit from a power re-distribution technique that helps predict generator outputs immediately after the occurrence of a contingency.
Ph. D.
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Nivens, Ryan Andrew. "Dilating Triangles: Using Measurement and Scale Factors to Investigate Area." Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etsu-works/218.
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Ghalambor, Afrooz, and Madeleine Latifi. "Designing a Process Measurement Program as a part of Measurement & Analysis Process Area of CMMI Level 2." Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-19577.
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This master’s dissertation stands as a guideline for defining a measurement program for GEEE that can be piloted at the Gothenburg site EEEG. The measurement program is based on the “CMMI process area Measurements and Analysis, Level 2”. The proposed measurement program is designed in such a way that is applicable for repeatable process measurement with potential minor alters depending on the nature of the process being examined. Major effort has been made on creating a program that not only collects the numerical data but also delivers substantial results in terms of goal setting, data analysis and decision making. Designing a process for measurement facilitate organizational strategy toward process improvements. This measurement program is designed with the help of some well-known methods such as: GQM (Goal-Question-Metric), PDCA (Plan-Do-Check-Act) and ETVX (Entry-Task-Validation- Exit) where five major phases are resulted, namely; Identify, Define, Collect data, Analysis, Evolve, thereafter embedded in a template-shaped tool. The whole template, after a complete fulfillment, would provide the organization with a guideline to achieve the organizational objectives. It is vital to mention that this template itself does not improve the processes. It only shows the status of the chosen project/process after having the filled template executed. What this template generates is to provide the stakeholders with necessary information and basis to make informed decision afterwards in order to improve the chosen processes/projects. Since the processes in “Maturity Level 2 of CMMI” are project based, it is important the status of processes can be measured and communicated. This procedure plays a crucial role in creating a platform for moving to the next maturity level.
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Hackett, Joshua Andrew. "Hydrogeology of the McKinney Butte Area: Sisters, Oregon." PDXScholar, 2011. https://pdxscholar.library.pdx.edu/open_access_etds/371.
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McKinney Butte, a late Tertiary andesite vent and flow complex, is located near the town of Sisters, Oregon, in the upper Deschutes Basin, and is situated along the structural trend that forms the eastern margin of the High Cascades graben (Sisters fault zone and Green Ridge). Rapid development and over appropriated surface water resources in this area have led to an increased dependence upon groundwater resources. A primary concern of resource managers is the potential impact of expanding groundwater use on stream flows and spring discharge. Two sets of springs (McKinney Butte Springs and Camp Polk Springs) discharge to Whychus Creek along the east flank of McKinney Butte, and during low-flow conditions supply a substantial component of the total flow in the creek. Despite their contribution to Whychus Creek, the springs along McKinney Butte are small-scale features and have received less attention than larger volume (> 2 m³/s) springs that occur in the basin (i.e., Metolius Spring and Lower Opal Springs). This study used discharge measurements in Whychus Creek upstream and downstream of the springs, and mixing models using measurements of electrical conductivity and temperature in the springs and Whychus Creek to determine the contribution of the springs to the creek. Isotopic, thermal, and geochemical signatures for the McKinney Butte and Camp Polk Springs, and local streams (Whychus Creek and Indian Ford Creek) and springs (Metolius Spring, Paulina Spring, Alder Springs, and Lower Opal Spring) were assessed to determine the source(s) of the McKinney Butte and Camp Polk Springs. The discharge and hydrochemical data along with hydraulic head data from local wells were used in the development of a conceptual model of groundwater flow for the McKinney Butte area. Discharge from the McKinney Butte Springs supplies the majority of water to Whychus Creek on the east flank of McKinney Butte (~0.20 m³/s), provides up to 46% of the flow in the creek, and is relatively stable throughout the year. Discharge from the Camp Polk Springs is less than 0.05 m³/s. Isotopic, thermal, and geochemical signatures indicate distinct sources for the McKinney Butte and Camp Polk Springs. Groundwater discharged at the McKinney Butte Springs is depleted in heavy stable isotopes (δD and δ¹⁸O) relative to the Camp Polk Springs. Recharge elevations inferred from stable isotope concentrations are 1800-1900 m for the McKinney Butte Springs and 950-1300 m for the Camp Polk Springs. Elevated water temperature in the McKinney Butte Springs relative to the average air temperature at the inferred recharge elevation indicates the presence of geothermal heat and implies deep circulation in the flow system. The temperature in the Camp Polk Springs is not elevated. The Camp Polk Springs, though not the McKinney Butte Springs, contain elevated concentrations of ions Cl, SO₄, and NO₃ that are indicative of contamination. The study results indicate the source of the Camp Polk Springs is shallow groundwater whereas the McKinney Butte Springs discharge water that has circulated deep in the groundwater flow system. Additionally, the hydrochemical traits of the McKinney Butte Springs are similar to Metolius Spring, suggesting discharge from the McKinney Butte Springs is controlled by the structural trend that forms the eastern margin of the High Cascades graben. The significant difference in discharge between the McKinney Butte Springs and Metolius spring may be related to the size of faults that occur locally.
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Jones, Timothy David. "Improving the precision of leg ulcer area measurement with active contour models." Thesis, University of South Wales, 1999. https://pure.southwales.ac.uk/en/studentthesis/improving-the-precision-of-leg-ulcer-area-measurement-with-active-contour-models(b365998c-1ae3-44b1-8232-c5f4a8121f97).html.
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A leg ulcer is a chronic wound of the skin that, at best, takes many months to fully heal and causes great distress to the patient. Treating leg ulcers places a large financial burden upon the National Health Service in the United Kingdom, estimated to be in excess of £300M annually. Measurement of the size of leg ulcers is a guide to assessing the progress of wound healing, and the use of non-invasive measurement techniques avoids damaging or infecting the wound. The area of a leg ulcer is currently measured by presenting a human observer with a captured video image of a wound, who then uses a mouse or pointing device to delineate the wounded region. Typically, the standard deviation of area measurements taken this way is approximately 5% of the wound area. In addition, different observers can show a bias difference in their area measurements from 3% to 25% of the wound area. It is proposed to reduce the incidence of such errors by using an active contour model to improve the delineation. Four different models are developed by adapting and applying several contributions made to the active contour model paradigm. Novel features include an external force that acts normally, but not tangentially, to the boundary, a new external energy term that promotes homogeneity of the gray level at the edge of the wound and the application of the minimax principle for setting the parameters of an active contour model with piecewise b-spline curves. The algorithms provide the physician with a new and practical tool for producing area measurements with improved precision and are semi-automatic, requiring only a manual delineation to start the algorithm. In most cases, measurement precision is improved by application of the algorithms. Many wounds give rise to measurable bias differences between average manual area measurements and the corresponding algorithmic area measurements, typically averaging 3% to 4% of wound area. With some wounds the bias magnitude can exceed 10% as a result of the contour partly deviating from the true edge of the wound and following a false edge.
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Babu, Srinivas Bandi Ramesh. "A measurement-based admission control mechanism for wireless local area networks." [Tampa, Fla] : University of South Florida, 2005. http://purl.fcla.edu/usf/dc/et/SFE0001403.
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BARIZON, BEN-HUR MONTEIRO. "PROPAGATION MEASUREMENT IN 2.4 GHZ FOR WIRELESS LOCAL AREA NETWORK PLANNING." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=5688@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORAs Redes locais sem fio (WirelessLAN ou WLAN) surgiram como uma alternativa as redes convencionais com fio (LAN), de uma forma mais flexível, de fácil configuração e boa conectividade em áreas fechadas (prediais) ou abertas (campus). Elas combinam a mobilidade do usuário com sua conexão a rede com taxas de comunicação de até 20 Mbps ou mais, empregando técnicas de espalhamento espectral (salto em frequência - FHSS ou sequência direta - DSSS) ou acesso por modulação de frequências ortogonais - OFDM, nas faixas de frequência de 900 MHz, 2.4 Ghz e 5.7 Ghz. Dependendo da tecnologia, faixa de frequência e ambiente de utilização, o alcance das WLAN pode variar de 30 a 250 metros, ou maiores distâncias com as evoluções deste padrão. O seu projeto requer o modelamento do canal de propagação em ambientes internos . Os métodos de previsão de perda de transmissão mais utilizados são de natureza semi-empírica, devido à complexidade do problema em que envolve múltiplos mecanismos de propagação como reflexão em paredes, pisos e tetos, difração em obstáculos e transmissão através de paredes e pisos. Além da perda de propagação deve ser considerado o problema do multipercursos que produz em espalhamento de retardos, o sinal recebido afetando a qualidade do sistema.
The Wireless Local Area Network (WirelessLAN or WLAN) appeared as an alternative the conventio nal Local Area Network (LAN), in a more flexible way, of easy configuration and good conectividade in closed areas (property) or open areas (campus). They combine user s mobility , his/her network connection with communication taxes of up to 20 Mbps or plus, using spread spectrum techniques (Frequency Hopping - FHSS or Direct Sequence - DSSS) or access for Orthogonais Frequency Division Modulation - OFDM, in frequency range of 900 MHz, 2.4 Ghz and 5.7 Ghz. Depending on the technology, frequency range and us e atmosphere, the reach of WLAN can vary from 30 to 250 meters, or larger distances with the evolutions of this pattern. This project requests the model of the propagation channel in internal atmospheres. The methods of forecast of transmission loss more used are of semi-empiric nature, due to the complexity of the problem in that it involves multiple propagation mechanisms as reflection in walls, floors and roofs, diffraction in obstacles and transmission through walls and floors. Besides the propagation loss it should be considered the problem of the multipath that produces in dispersal of retards, the received sign affecting the quality of the system.
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Prasad, N. G. Narasimha Carleton University Dissertation Mathematics. "Small area estimation and measurement of response error variance in surveys." Ottawa, 1985.
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McCarthy, Michael. "A rectilinear and area position calibration facility of sub-micrometre accuracy in the range 100-200mm." Thesis, Cranfield University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364758.
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Marshall, L. "Year 7 students' understanding of the relationship between area and perimeter." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 1997. https://ro.ecu.edu.au/theses/900.
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The aim of this study was to determine Year 7 students' understanding of the relationship between area and perimeter. This is an important part of the measurement strand of mathematics. Two methods of collecting data were used: a multiple-choice pencil-and-paper test item; and clinical interviews with a class of Year 7 students. Two Perth metropolitan government primary schools allowed access for the research to take place: one was used for the trial of the test item with eleven students; the students at the other school were given the validated test item followed, one week later, by clinical interviews. Analysis of the data suggested that students of this year level have a sound understanding of the concept of perimeter, but that their understanding of the area concept was not as well developed. There also did not appear to be a widespread understanding of the relationship between area and perimeter. Several categories of understandings and misunderstandings were identified, as were other areas of concern. The research highlights some interesting implications for teachers. A better understanding of their students' beliefs about the concepts of area, perimeter, and the relationship between the two, may influence teachers' decisions when planning for the teaching of these attributes of measurement
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Alsafih, Hamza A. "Transmission stability enhancement using Wide Area Measurement Systems (WAMS) and critical clusters." Thesis, University of Bath, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607141.
Full textAbstract:
Due to the on-going worldwide trend towards investment in de-regulated electricity markets driven by political, economic and environmental issues, increasing interconnection between modern power systems has made power system dynamic studies much more complex. The continuous load growth without a corresponding increase in transmission network capacities has stressed power systems further and forced them to operate closer to their stability limits. Large power transfers between utilities across the interconnections stress these interconnections. As a result, stability of such power systems becomes a serious issue as operational security and reliability standards can be violated. On the other hand, the evolving technology of Wide-Area Measurement Systems (WAMS) has led to advanced applications in Wide-Area Monitoring, Protection and Control (WAMPAC) systems, which offer a cost-effective solutions to tackle these challenging issues. The main focus of this research project was to develop a wide-area based stability enhancement control scheme for large interconnected power systems. A new method to identify coherent clusters of synchronous generators involved in wide area system oscillations was the initial part of the work. The coherent clusters identification method was developed to utilise measurements of generators speed deviation signals combined with measurements of generators active power outputs to extract coherency property between system's generators. The obtained coherency property was then used by an agglomerative clustering algorithm to group system's generators into coherent clusters. The identification of coherent clusters was then taken as a base to propose a new structure of a WAMS based stability control scheme. The concept of WAMS and a nonlinear control design approach (fuzzy logic theory) was used to provide a comprehensive new control algorithm. The objectives of the developed control scheme were to enhance and improve the control performance of modern power systems. Thus, allowing improved dynamic performance under severe operation conditions. These objectives were achieved by means of enhanced damping of power system oscillations, enhanced system stability and improved transfer capabilities of the power system allowing the stability limit to be approached without threatening the system security and reliability.
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Chiow, Sheng-wey. "A precision measurement of the photon recoil using large area atom interferometry /." May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Zand, Emad Dolatshahi. "Measurement of TOA using frequency domain techniques for indoor geolocation." Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-0428103-130325.
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Zographos, A. N. "A line-scan system for the inspection and measurement of cylindrical surfaces." Thesis, Nottingham Trent University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245636.
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O'Flynn, Alexander W. "Testing of Phasor Measurement Units (PMUs) for Distribution Network Applications." Thesis, Queensland University of Technology, 2020.
Find full textAbstract:
Enabling islanded operation of power distribution networks will greatly improve the reliability of supply for customers. Measurement devices such as Phasor Measurement Units (PMUs) are required to protect and control the islanded network. PMUs are widely used in transmission network. This thesis examines whether existing PMUs meet the performance requirements to enable islanded distribution network operation.
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Yoon, Yeo Jun. "Study of the utilization and benefits of phasor measurement units for large scale power system state estimation." Texas A&M University, 2005. http://hdl.handle.net/1969.1/3345.
Full textAbstract:
This thesis will investigate the impact of the use of the Phasor Measurement Units
(PMU) on the state estimation problem. First, incorporation of the PMU measurements in a
conventional state estimation program will be discussed. Then, the effect of adding PMU
measurements on the state estimation solution accuracy will be studied. Bad data
processing in the presence of PMU measurements will also be presented. Finally, a multiarea
state estimation method will be developed. This method involves a two level
estimation scheme, where the first level estimation is carried out by each area
independently. The second level estimation is required in order to coordinate the solutions
obtained by each area and also to detect and identify errors in the boundary measurements.
The first objective of this thesis is to formulate the full weighted least square state
estimation method using PMUs. The second objective is to derive the linear formulation of
the state estimation problem when using only PMUs. The final objective is to formulate a
two level multi-area state estimation scheme and illlustrate its performance via simulation
examples.
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Retty, Hema A. "Evaluation and Standardizing of Phasor Data Concentrators." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/32064.
Full textAbstract:
The power grid is interconnected in many ways; so that when disturbances occur in a small region, their effects can be seen across large areas causing major blackouts. In order to isolate the fault, measurements taken at different times throughout the blackout need to be collected and analyzed. With each measurement device having its own time source, time alignment can be a quite tedious and lengthy process. The need for a new time synchronized measurement device has arrived. The Phasor Measurement Units (PMU) is not only GPS time synchronized, but it also takes measurements as voltage and current phasors.
PMUs are becoming an integral part in many power system applications from load flow analysis and state estimation to analyzing blackout causes. Phasor Data Concentrators (PDC) collect and process PMU data. As such, it is important that PMU and PDC communication is seamless. PDCs are set up at multiple utilities and power authorities and also need to be able to communicate and send data to one another seamlessly to encompass analysis of large measurement systems. If these devices are not working similarly when processing and sending/receiving data, unnecessary problems may arise. Therefore it is important that there is an expectation as to how they should work. However, what is expected from these devices is not entirely clear. For this reason, standards such as IEEE C37.118.2-2011 [5] have been proposed to help make operation as uniform as possible. Unfortunately, the standards for PDCs are lacking and tend to only set up communication protocols. To help normalize PDCs, these standards need to be expanded to include all PDC operations and give little room for discrepancy as to what a PDC should do in any given situation. Tests have been performed on PDCs not only to see how they match up to current standards but on how they act outside of the standards.Master of Science
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Zora, Leydi Tatiana. "Thesis PMU Applications Prioritization Based in Wide Area Disturbance Events." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/71829.
Full textAbstract:
Synchrophasor Measurement Units (PMUs) are devices that can not only measure but also time stamp voltage, current, frequency, among others. PMUs take these synchronized measurements as fast as 60 times per second; compared with the traditional 2-4 second SCADA measurements, PMUs bring a much clear and real-time picture of what is happening in the power system. PMUs have been increasingly deployed across transmission power grids worldwide. In the USA this is primarily done by utilities through projects sponsored mainly by SIGS and Smart Grid grants. There are different applications that synchrophasors can provide, including off-line and real-time applications. However, due to budget constraints, technology development and characteristics specific to each system, not all applications are equally suitable and essential for all electric power systems. This thesis provides a method for PMU applications prioritization based on the analysis and results of wide area disturbance events.Master of Science
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Mascolo, Rosario, C. Bruno, Rosa-Giglio P. De, G. Zorzi, F. Pepe, and G. Calvanese. "Measurement of leather surface - 308: variability in the measurement using electronic and pin wheel devices on different kind of leathers." Verein für Gerberei-Chemie und -Technik e. V, 2019. https://slub.qucosa.de/id/qucosa%3A34264.
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Content:
Finished leather is a material purchased by surface measurement. Compared to other goods, which value is defined by a measure, for leather there is no certified reference material able to represent the numerous types of articles present on the market. Moreover, there is not a single type of machine, with the consequent difficulties in comparison of data obtained by different devices on different kind of leather.
As far as the devices available are concerned, the pin-wheels machine was the most used device until the sixties, period after which the increasingly massive diffusion of electronic machines began. With regard to the tolerance allowed, in late nineties an agreement between the ICT and ICHSLTA was reached (International Contract N. 7): 2% and 3% for soft and elastic leathers. These limits were fixed
without considering the possible deviation of results using different devices and without considering the reproducibility of measures in function of the effective flexibility and physical characteristics of leathers.
Over the years, however, the pin-wheel machines have been completely substituted and, due to the high costs of maintenance and management of the pin-wheel machines, only a few of the institutes recognized by ICT, including the SSIP, are equipped with a fully functional pin-wheel machine. Despite this evidence, the Contract continues to consider pin-wheel machine as the reference one for disputes.
For the above, an extensive data collection campaign has been carried out involving all the industrial chain of leather: tanneries, brands, users, laboratories, research institutes and devices manufacturers.
16 different kind of leather articles, representative different leather uses (gloves, apparel, footwear, leather goods, furniture, automotive), were measured using all the machines currently available on the
market (roller, conveyor, scanner and digital image acquisition devices) and considering ISO 19076 and ISO 11646 measurement procedures as the reference ones. Thousands of data are now available to qualify the behaviour of the leather for each type of machine with its specific characteristics. This was done by statistical robust analysis of the data and by the comparison of the values obtained with the pin machine.
The leather used were also mechanically characterized in order to be able to identify any correlations with the reproducibility of the measurements and with the imposed tolerances.
Take-Away:
The purpose is the possibility to overcome all the restrictions connected with the pin-wheel machine, the improvement of actual EN ISO methods of leather measurement and a better instrument to define
tolerances considering the couple leather-machine.
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Guenet, Frederique S. A. "Quantification of valvular regurgitation by proximal isovelocity surface area and magnetic resonance imaging." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/11207.
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Zandieh, Behdis. "Indoor Wireless Local Area Network (WLAN) : Measurement and Modeling from a user perspective." Thesis, KTH, Kommunikationssystem, CoS, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-92012.
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If we had detailed wireless local area network (WLAN) coverage maps, both staff and equipment could be used more efficiently, for example, less time would be spent searching for connectivity. In addition, system administrators could understand their WLAN's utilization better, thus enabling better planning for where to install new access points, where to remove access points, where to change the type of antenna, etc. This thesis concerns creating detailed indoor coverage models by using measured network performance - in order to enable both users and administrators to visualize the network coverage. Today a user can only easily know about the access points that they currently hear – in the location where they currently are. Giving the users and administrators access to a model of the entire campus coverage will allow them to understand not only the _local_ coverage, but the patterns of coverage (or lack there of). However, no efficient modeling techniques are currently available for those deploying and operating indoor WLANs. The thesis begins with some general background information and then examines a number of WLAN survey tools; in terms of both their performance and cost. Following this a number of related projects are presented. This background provides the motivation for why a new tool is needed and what functions such a tool should have. Next a site survey of the KTH campus in Kista was conducted using a newly developed survey application. This application was developed to better meet the requirements derived from the missing functionality of existing tools. In addition, developing this application gave the author an opportunity to learn a new objectoriented programming language, i.e. C# and the .NET environment. Learning to use this new environment was essential to building both an easy to use application and collecting the data from the system - the later was often not straight-forward. ne of the key issues after data collection is how to present the collected data to the user and how this varies depending upon the user’s interests and task. An initial representation of the experimental data is presented as a manually painted coverage map overlayed onto a map. Next the thesis examines how to integrate the experimental data using Google’s SketchUp in order to build a 3D model of the WLAN coverage on this campus. Future work related to this thesis should focus on how to automate the collection of data and how to automate the presentation of the resulting experimental data.Om vi hade tillgång till detaljerade täckningskartor över lokala nätverk (WLAN), skulle både personal och utrustning kunna användas mer ändamålsenligt. Till exempel skulle mindre tid gå åt till att söka täckning. Dessutom skulle systemadministratörer förstå användningen av deras WLAN:s på ett bättre sätt, vilket skulle möjliggöra bättre planering av var nya accesspunkter ska installeras, var accesspunkter ska tas bort, var man ska byta antenntyp, osv. Detta examensarbete handlar om skapande av detaljerade täckningsmodeller för användning inomhus vilka genererats genom att mäta nätverkets styrka – detta för att göra det möjligt för båda användare och administratörer att visualisera nätverkstäckning. Idag kan en användare endast känna till accesspunkter som de just för tillfället hör – på den plats där de för tillfället befinner sig. Att ge användarna och administratörerna tillgång till en modell av täckningen över hela Campus skulle inte bara göra att de uppfattade den lokala täckningen utan hela täckningsmönster (eller avsaknaden därav). Dock finns för tillfället inga ändamålsenliga modelleringstekniker för de som utvecklar och sköter WLAN:s inomhus. Examensarbetet inleds med en del bakgrundsinformation och går därefter in på ett antal metoder för att kartlägga WLAN, både vad gäller prestanda och kostnad. Härefter presenteras ett antal relaterade projekt. Denna bakgrund är till för att motivera varför ett nytt verktyg behövs och vilka funktion ett sådant verktyg borde ha. Efter denna litteratur- och bakgrundsstudie gjordes en kartläggning av KTH Campus i Kista med användning av en nyligen utvecklad applikation. Applikationen togs fram för att på ett bättre sätt uppfylla kraven som följde av saknade funktioner i existerande verktyg. Dessutom gav utvecklingen av applikationen författaren en möjlighet att lära sig objektorienterad programmering med t ex C# och .NET-miljön. Att lära sig att använda denna nya programmeringsmiljö var en nödvändighet för att kunna bygga både en lättanvänd applikation och samla in data från systemet – de senare var oftast inte helt lätt. En av de största svårigheterna efter datainsamlingen var att hitta ett sätta att presentera den insamlade informationen samt hur presentationen ska variera beroende på användaren behov och uppgift. En första presentation av experimentdata presenteras som en manuellt ritad täckningskarta lagd ovanpå en vanlig karta. Nästa steg i examensarbetet är att undersöka hur man ska integrera experimentdata genom att använda Google:s SketchUp för att bygga en 3D-modell av WLAN-täckning på Campus i Kista. Framtida utveckling relaterad till detta examensarbete borde fokusera på hur man ska kunna automatisera datainsamlingen och presentationen av resulterande experimentdata.
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Almutairi, Abdulaziz. "Enhancement of power system stability using wide area measurement system based damping controller." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/enhancement-of-power-system-stability-using-wide-area-measurement-system-based-damping-controller(7d98d164-8051-4662-ad18-374620d28a00).html.
Full textAbstract:
Contemporary power networks are gradually expanding incorporating new sources of electrical energy and power electronic based devices. The major stability issue in large interconnected power systems is the lightly damped interarea oscillations. In the light of growth of their incidents there are increased concerns about the effectiveness of current control devices and control systems in maintaining power system stability. This thesis presents a Wide Area Measurement System (WAMS) based control scheme to enhance power system stability. The control scheme has a hierarchical (two-level) structure comprising a Supplementary Wide-Area Controller (SWAC) built on top of existing Power System Stabilisers (PSSs). The SWAC's focus is on stabilising the critical interarea oscillations in the system while leaving local modes to be controlled entirely by local PSSs. Both control systems in the two levels work together to maintain system stability. The scheme relies on synchronised measurements supplied by Phasor Measurement Units (PMUs) through the WAMS and the only cost requirement is for the communication infrastructure which is already available, or it will be in the near future. A novel linear quadratic Gaussian (LQG) control design approach which targets the interarea modes directly is introduced in this thesis. Its features are demonstrated through a comparison with the conventional method commonly used in power system damping applications. The modal LQG approach offers simplicity and flexibility when targeting multiple interarea modes without affecting local modes and local controllers, thus making it highly suitable to hierarchical WAMS based control schemes. Applicability of the approach to large power systems is demonstrated using different scenarios of model order reduction. The design approach incorporates time delays experienced in the transmission of the SWAC's input/output signals. Issues regarding values of time delays and required level of detail in modelling time delays are thoroughly discussed. Three methods for selection of input/output signals for WAMS based damping controllers are presented and reviewed. The first method uses modal observability/controllability factors. The second method is based on the Sequential Orthogonalisation (SO) algorithm, a tool for the optimal placement of measurement devices. Its application is extended and generalised in this thesis to handle the problem of input/output signal selection. The third method combines clustering techniques and modal factor analysis. The clustering method uses advanced Principal Component Analysis (PCA) where its draw backs and limitations, in the context of power system dynamics' applications, are overcome. The methods for signal selection are compared using both small signal and transient stability analysis to determine the best optimal set of signals. Enhancement of power system stability is demonstrated by applying the proposed WAMS based control scheme on the New England test system. The multi-input multi-output (MIMO) WAMS based damping controller uses a reduced set of input/output signals and is designed using the modal LQG approach. Effectiveness of the control scheme is comprehensively assessed using both small signal and transient stability analysis for different case studies including small and large disturbances, changes in network topology and operating condition, variations in time delays, and failure of communication links.
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Slama, Jens. "Evaluation of a new measurement method for tire/road noise." Thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-100770.
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Noise is a growing health concern as urban residents increases rapidly and more reports of noise causing sleep disturbances and increasing the risk of cardiovascular health problems are published. Noise has a negative influence on life quality. This life quality deficiency also shows in housing and office pricing in noisy environments. Housing and office prices are often higher in quiet areas than in noisy areas. Therefore noise is both a health issue and has big economic consequences. The biggest contributor to the road traffic noise is the tire/road noise at speeds above 50km/h. Therefore this is an important aspect to monitor and the problem has to be alleviated. In this thesis the client Ramböll has gotten many contracts concerning the state of the roads from governmental institutes. As a part of the evaluation of the roads they want to implement the noise emission as a factor. This gives the government institutions another parameter that helps in the decision of which part of the road network to refurbish first. In the effort to decide what is best way for Ramböll to measure noise a new setup for measuring noise has been developed. The most used ways of measuring tire/road-noise is the close proximity (CPX) -method and the statistical pass-by (SPB) -method. These methods both give accurate results but they have drawbacks. The SPB measurements are time consuming and only give noise levels for a small patch of a road. CPX measurement on the other hand require costly and time consuming development of a measurement trailer. Certifying the trailer and maintenance work of it is expensive. So this report shows a first step in how to build a measurement setup and what aspects were taken into consideration when it was designed. A close proximity measurement setup in the form of a tube with a microphone placed inside it was built and installed underneath the measurement vehicle. The measurement setup designed and built was named the Tube-CPX measurement setup in this report. The measurements performed with this Tube-CPX measurement setup show promising results. Similarities between CPX measurement setup and the Tube-CPX setup have been found both in the frequency spectrum as well as in the relation with pass-by measurement noise levels. The repeatability of the Tube-CPX measurements is even better than the compared CPX measurements. Although results are promising more work is required before the Tube-CPX setup can be seen in operation at Ramböll. In particular the question which source causes which sound pressure is required to understand the measured levels. And also more controlled pass-by measurements have to be performed to determine the relation of the absolute values measured at the tire/road impact spot to the values that are most interesting, namely the sound pressure levels that the human at the side of the road depicts.
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Yang, Xue Jiao. "Supervisory wide-area control for multi-machine power system." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/supervisory-widearea-control-for-multimachine-power-system(6c0575f9-7b20-4751-9d67-276aaaa4c7b2).html.
Full textAbstract:
With the increasing demand for electrical power and the growing need for the restructuring of the power industry, electric power systems have become highly complex with inherent complicated dynamics. Therefore, the study of power system stability has continued to receive significant attention from both academic researchers and industrial practitioners. This thesis focuses on supervisory wide-area control for rotor angle stability of multi-machine power systems using Linear Quadratic Gaussian/Loop Transfer Recovery (LQG/LTR) control theory with guaranteed robustness. The supervisory controllers are developed in both continuous-time and discrete-time framework and their performances and robustness are assessed using both frequency-domain tools, and time-domain simulation results. The impact of the communication time-delays that commonly exist in wide-area power system control on the performance and robustness of the closed-loop system is investigated. In particular, different methods of incorporating such time-delays into the design of the supervisory LQG controller are considered. This thesis proposes a modified supervisory LQG controller that utilizes the Extended Kalman Filter to estimate the unknown/varying time-delays. Simulation results obtained using numerical examples involving non-linear power system models demonstrate the benefits of the proposed scheme for both time-invariant and time-varying delays. The resulting supervisory control scheme is well suited for maintaining power system stability in the presence of communication time-delays.
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Quint, Ryan David. "Practical Implementation of a Security-Dependability Adaptive Voting Scheme Using Decision Trees." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/35667.
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Todayâ s electric power system is operated under increasingly stressed conditions. As electrical demand increases, the existing grid is operated closer to its stable operating limits while maintaining high reliability of electric power delivery to its customers. Protective schemes are designed to account for pressures towards unstable operation, but there is always a tradeoff between security and dependability of this protection.
Adaptive relaying schemes that can change or modify their operation based on prevailing system conditions are an example of a protective scheme increasing reliability of the power system. The purpose of this thesis is to validate and analyze implementation of the Security-Dependability Adaptive Voting Scheme. It is demonstrated that this scheme can be implemented with a select few Phasor Measurement Units (PMUs) reporting positive sequence currents to a Phasor Data Concentrator (PDC). At the PDC, the state of the power system is defined as Stressed or Safe and a set of relays either vote or perform normal operation, respectively.
The Adaptive Voting Scheme was implemented using two configurations: hardware- and software-based PDC solutions. Each was shown to be functional, effective, and practical for implementation. Practicality was based on the latency of Wide Area Measurement (WAM) devices and the added latency of relay voting operation during Stressed conditions. Phasor Measurement Units (PMUs), Phasor Data Concentrators (PDCs), and relay operation delays were quantified to determine the benefits and limitations of WAMS protection and implementation of the voting scheme. It is proposed that the delays injected into the existing protection schemes would have minimal effect on the voting scheme but must be accounted for when implementing power system controls due to the real-time requirements of the data.Master of Science
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Ashton, Phillip Michael. "Exploiting phasor measurement units for enhanced transmission network operation and control." Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/9063.
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In order to achieve binding Government targets towards the decarbonisation of the electricity network, the GB power system is undergoing an unprecedented amount of change. A series of new technologies designed to integrate massive volumes of renewable generation, predominantly in the form of offshore wind, asynchronously connecting to the periphery of the transmission system, are transforming the requirements of the network. This displacement of traditional thermal generation is leading to a significant reduction in system inertia, thus making the task of system operation more challenging. It is therefore deemed necessary to develop tools and technologies that provide far greater insight into the state of the power system in real-time and give rise to methods for improving offline modelling practices through an enhanced understanding of the systems performance. To that extent PMUs are seen as one of the key enablers of the Smart Grid, providing accurate time-synchronised measurements on the state of the power system, allowing the true dynamics of the power system to be captured and analysed. This thesis provides an analysis of the existing PMU deployment on the GB transmission system with a view to the future system monitoring requirements. A critical evaluation and comparison is also provided on the suitability of a University based Low Voltage PMU network to further enhance the visibility of the GB system. In addition a novel event detection algorithm based on Detrended Fluctuation Analysis is developed and demonstrated, designed to determine the exact start time of a transmission event, as well as the suitability of such an event for additional transmission system analysis, namely inertia estimation. Finally, a reliable method for the estimation of total system inertia is proposed that includes an estimate of the contribution from residual sources, of which there is currently no visibility. The proposed method identifies the importance of regional inertia and its impact to the operation of the GB transmission system.
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Youngman, Elizabeth Anne. "The Development of Curriculum-based Measurement Local Norms in the Area of Written Expression." TopSCHOLAR®, 2010. http://digitalcommons.wku.edu/theses/174.
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This project used Curriculum-Based Measurement (CBM) in the area of Written Expression to establish district norms for Bowling Green City Schools. CBM uses brief fluency measures as indicators of students' academic performance. With the use of CBM, it is possible to identify students who are considered to be at-risk for educational performance. AIMSweb probes were used to assess 1,565 first through fifth grade students from five elementary schools within the Bowling Green Independent School District. Performance was scored using the three most common scoring indices: Total Words Written (TWW), Words Spelled Correctly (WSC), and Correct Word Sequence (CWS). Data collected from this study are presented as norms at the building and district-wide levels. Each table (see Tables 2 -16) indicates student performance from each school on TWW, WSC, or CWS for a specific grade level. The tables illustrate what raw score corresponds to percentile ranks at the 10th,16th, 25th, 50th, 75th, 84th, and 90th percentiles. The 50th percentile would be considered typical performance for an "average" student at that particular time of year and grade level. Findings from this study will be beneficial in making educational decisions regarding students potentially at risk for difficulties in the area of written expression.
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Remmen, Krystle D. "A REACTIVE TRACER METHOD FOR THE MEASUREMENT OF SPECIFIC SURFACE AREA IN EGS RESERVOIRS." Thesis, California State University, Long Beach, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1527408.
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Early thermal breakthrough is an issue of concern in the geothermal industry, especially with regard to engineered geothermal systems (EGS). Determination of the specific surface area (SSA) of the fluid/rock interface in an EGS is vital to predicting early thermal breakthrough. An approach to this problem involving the application of tracers with different sorption properties (lithium, bromide, and deuterium) is presented. Upon injection into a reservoir, these tracers react along the fluid/rock interface to varying degrees. The resulting breakthrough separation at the extraction well can be used to derive SSA by applying a modified form of the advection-dispersion equation. For proof of concept, field tests were conducted in a sandstone bedding-plane fracture near Chazy, New York. Results showed minimal breakthrough separation, indicating insufficient sweep of the fracture area, and that lithium was not an ideal tracer in this medium. However, a relative measure of SSA can still be derived.
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McPhail, Diane, University of Western Sydney, College of Arts, and School of Education. "Area : the big cover-up." 2007. http://handle.uws.edu.au:8081/1959.7/27435.
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The research problem reported in this thesis is an investigation of the teaching and learning of area measurement in the early years of school. Research indicates that children confuse the measurement of area and perimeter and also the use of linear and two-dimensional units of measure. The first phase of the study investigated the knowledge and skills which underpin an understanding of the L x B formula for calculating rectangular area. Those factors were used to plan a teaching program of four lessons for Year 1 and Year 2 children, focusing on: establishing the attribute of area; making, describing and drawing the spatial structure of arrays of repeated informal units to measure areas; and methods of counting to determine the total number of units. The effectiveness of the program was evaluated by implementing the lessons in four classes. Lessons planned from the then current syllabus were implemented in another four classes. Comparison of student learning outcomes from all classes indicated that the research lessons were more effective in assisting children to develop an understanding of a grid pattern or array of repeated informal units. The second phase of this study described the researcher’s investigation, design and trial of teacher professional learning strategies which would assist teachers to adopt successful methods of teaching young children to measure area. Seventeen volunteer teachers in seven school teams participated in one of three models of professional learning, based on varying levels of consultancy support. The models were based on the provision of lesson notes and teaching materials, facilitation of team meetings to discuss the implementation, and the provision of additional time to interview individual children following each lesson. Participation in the project assisted all of the participating teachers to develop their content knowledge and to modify their teacher-centred teaching practices. The key strategies and factors which contributed to this success included ongoing school based professional dialogue and support, the provision of a teaching program which emphasised students’ conceptual development within a sequence of activities, the role played by teacher leaders within each team, opportunities to develop questioning techniques and the motivation and disposition of the participating teachers.ABSTRACTDoctor of Philosophy (PhD)
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Yang, Cheng-Han, and 楊承翰. "Area-Efficient One-Period Delay Jitter Measurement." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/55031029915294714988.
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碩士國立彰化師範大學
電子工程學系
97
In this thesis, a true one-period delay circuit is proved to be actually a synchronous mirror delay. An area-efficient all-digital synchronous mirror delay is thus developed as a true one-period delayline for cycle-to-cycle jitter measurement. In our preliminary work we develop an area-efficient SMD. The power dissipation can thus be also reduced. A VDL is designed for the testability of the SMD [11]. In the comparison pervious work, the author in [10] first develop a one period delay circuit. They add some control gates to a long VDL and generate the postponed signal and a one-period delayed signal with the same latency TD. It seems that they expected to measure the ith jitter T(i+1)-Ti via the second VERNIER DELAYLINE, however they actually capture the jitters, that is not the jitter compared to the previous period but the intrinsic jitter generated by their ONE PERIOD DELAY itself. In this thesis, the SMD is implanted to be a True One Period delayline. From measured results of implementation, the proposed true one-period delay jitter measurement circuit suffers low resolution but saves 75% of area overhead and the associated power dissipation.
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SilviaJocunda and 岑宛珊. "Field Measurement and Analysis of Green Area Cooling Effect on Surrounding Area." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/9z7ks9.
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Chen, Lang. "Wide-Area Measurement Application and Power System Dynamics." 2011. http://trace.tennessee.edu/utk_graddiss/1174.
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Frequency monitoring network (FNET) is a GPS-synchronized distribution-level phasor measurement system. It is a powerful synchronized monitoring network for large-area power systems that provides significant information and data for power system situational awareness, real time and post-event analysis, and other important aspects of bulk systems. This work explored FNET measurements and utilized them for different applications and power system analysis.
An island system was built and validated with FNET measurements to study the stability of the OTEC integration. FNET measurements were also used to validate a large system model like the U.S. Eastern Interconnection. It tries to match the simulation result and frequency measurement of a real event by adjusting the simulation model. The system model is tuned with the combination of different impact factors for different confirmed actual events, and some general rules and specific tuning quantities were concluded from the model validation process.
This work also investigated the behavior of the power system frequency during large-scale, synchronous societal events, like the World Cup, Super Bowl and Royal Wedding. It is apparent that large groups of people engaging in the same event at roughly the same time can have significant impacts on the power grid frequency. The systematic analysis of the accumulating and statistical FNET frequency data presents an incisive point of view on the power grid frequency behavior during such events.
To better understanding of system events recorded by FNET, a visualization tool was developed to visualize major events that occurred in the North American power grid. The measurement plot combined with the geographical contour map provides intuitive visualization of the event.
Finally, the EI system was simplified and clustered into four groups based on FNET measurements and simulation results of generator trip cases. The generation and load capacity of each cluster was calculated based on the clustering result and simulation model, and a flow diagram of this simplified EI system was demonstrated with clusters and power flow between them.
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Lin, Chia-Ying, and 林佳瑩. "Intrusion Detection Based on Triangle Area Similarity Measurement." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/94727948405971840697.
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碩士國立中正大學
會計與資訊科技研究所
96
Intrusion detection is a very important research issue in network security nowadays. Intrusion detection can be approached by data mining and machine learning techniques. In literature, advanced techniques by hybrid learning or ensemble methods have been considered, and they are superior to the models using single machine learning techniques. This thesis proposes a triangle area similarity measure combining the hybrid method, namely Triangle Area based Nearest Neighbors (TANN), in order to detect attacks more effectively. In TANN, we use k-means to obtain five cluster centers and transform data for k-NN classification by triangle area similarity measurement. By using KDDCup 99’ as the dataset and considering 10-fold cross validation, the experimental results show that TANN can effectively detect intrusion attacks and achieve higher detection and lower error rates than three baseline models based on support vector machines, k-NN, and the hybrid model combining k-means and k-NN.
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Hsu, Yao-Wen, and 許耀文. "The Measurement and Database of Hand Surface Area." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/66256970144618224194.
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博士國立清華大學
工業工程與工程管理學系
96
This study is to measure hand surface area (HSA) and palm surface area (PSA) using 3-D scan, and establish the database and estimation formulae. The hand surface area is a very important reference in many applications. Nevertheless, the measurement methods of hand surface area were inaccuracy and the resultant data are significantly varied among different researches in the past. Thus there were wrong data and confused in practical application. Due to the advent of 3-D measurement technology, we intend to use the high resolution 3-D hand scanner to measure the hand of 270 samples, 135 for each gender. The samples will be proportionally drawn among 5 statures and 3 body weights based on population distribution. The precision and accuracy of the scanner is within 0.67%. We will apply the Anthro 3-D computing software to compute the two kind of hand surface area and the percentages of total body surface area to establish a hand surface area database. First, the results of HSA and PSA are tabulated on 15 strata for the male, the female and the Total (two genders combined). A comparison between this study and previous textbook values (such as the Lund and Browder chart and the UK teaching text) show that previous textbooks over estimated HSA 8.0 % and PSA 10.7% for the total. Gender, body weight group and stature group were significant factors. The mean %HSA/BSA and mean %PSA/BSA were found to be 2.29% (0.24%) and 0.89% (0.09%), respectively. Gender and body weight group were significant factors. Then 6 1-D measurements were extracted semi-automatically to be used as candidate estimators for HSA and PSA estimation formulae. Stepwise regressions on these 6 1-D measurements and variable dependency test were performed. The results show that with a pair of measurements -- hand length and hand breadth -- is able to account 96% of HSA variance and up to 98% of PSA variance. Finally, the accuracy of this study is better than previous studies.
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YAN, LIANG-YU, and 顏良宇. "Study on wide-area dynamic frequency measurement technology." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/69632683386010634434.
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碩士長榮大學
資訊管理學系(所)
102
The system frequency is an important parameter to observe the dynamics for a power system. The operation information of power systems, such as dynamic changes between supply and load, system operation conditions etc., can be observed through wide-area frequency measurement. In this thesis, a study on the core technologies of wide-area frequency measurement, synchronous sampling pulse generator and frequency calculation method, is conducted. A digital synchronous sampling pulse generator is developed with Hardware Description Language(VHDL) and synthesized into the FPGA. Its synchronization error can be maintained within 60 ns. For calculating values of frequency, a method, combining the reference model in IEEEC37.118.1-2011 standard and moving average approach, is developed. The accuracy of frequency calculation meets P-class requirements for steady-state and dynamic conditions in the IEEE standard.
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Hou, Bo-Wen, and 侯博文. "Large Power System Stabilization by Wide Area Measurement." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/65155882173493563041.
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碩士國立臺灣海洋大學
電機工程學系
93
Wide area measurements in large-scale power systems have become feasible due to the technology of GPS-based Synchronized Phasor Measurement Units. Synchronized phasor measurements have been proven useful for many control and monitoring applications in power system. The purpose of this thesis is to study the improvement for system damping in Taipower system by installing power system stabilizers with wide area measurement. Furthermore, this thesis also includes the criteria of realistic application of the stabilizer such as: installation location, the selection of signals, and the impact to the whole system stability due to the signals transmission delay. In addition, the thesis analyzed the Inter-area mode in Taipower system, and verified the feasibility of installing such stabilizers in large power system.
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Huang, Hsin-Mei. "Children's understanding of the concepts of area measurement /." 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3337796.
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Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008.Source: Dissertation Abstracts International, Volume: 69-11, Section: A, page: 4228. Adviser: Klaus G. Witz. Includes bibliographical references (leaves 172-180) Available on microfilm from Pro Quest Information and Learning.
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LIN, CHI-TUN, and 林奇暾. "Motor Performance Measurement with Controller Area Network Communication." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/5k636r.
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碩士國立臺灣科技大學
電機工程系
106
This thesis is concerned with the development of motor performance measurement with controller area network (CAN) communication interface. The CAN protocol is the basis of communication network for the proposed method. Communication network connects motor power converters and its performance measurement scheme so that the monitor interface can be conducted by graph and chart control software called Labview. That is, the supervisor can monitor the performance of motor instantly. The CAN to universal serial bus (USB) converter with the CAN module in digital signal processor is used to implement the examination and scheduling for CAN. The high-performance and low-cost digital signal processor, TMS320F28069, is adopted as the system core. The power and efficiency calculations are conducted by the feedback signals of voltage, current, speed, and torque. When the speed of the three-phase induction motor(IM) is 2000 rpm, and the load torque is 5 N-m, the experimental results show that the input and output powers of the IM input power inverter are 1673.54 W and 1524.67 W, respectively, yielding an efficiency of 91.1%. The output power of IM is 1237.16 W and its efficiency is 81.14%. The three-phase permanent magnet synchronous generator(PMSG) operates in constant torque control for 5 N-m, so the electromagnetic torque of three-phase IM should be more than 5 N-m. Thus, the measured torque values of three-phase IM are larger than the commanded ones of three-phase PMSG. Comparing the results from the proposed method with power meter measurements, the differences of the input and output powers are 0.78% and 1.04%, respectively. The accuracy from the proposed measurements can match up with commercial instruments. The experimental results verify the implementation of both accurate data transfer from CAN to remote computer and its simultaneous control for the power converter. In conclusion, the experimental results verify the feasibility of the proposed method.