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Статті в журналах з теми "PQ PROBLEMS"

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Öhnell, Richard F. "Some PQ problems." Acta Medica Scandinavica 130, S206 (April 24, 2009): 17–19. http://dx.doi.org/10.1111/j.0954-6820.1948.tb12015.x.

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Arov, D. Z., B. Fritzsche, and B. Kirstein. "Completion problems forj pq-inner functions. II." Integral Equations and Operator Theory 16, no. 4 (December 1993): 453–95. http://dx.doi.org/10.1007/bf01205289.

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Arov, D. Z., B. Fritzsche, and B. Kirstein. "Completion problems forj pq-inner functions. I." Integral Equations and Operator Theory 16, no. 2 (June 1993): 155–85. http://dx.doi.org/10.1007/bf01358952.

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Bjerring, Jens Christian, and Wolfgang Schwarz. "Granularity Problems." Philosophical Quarterly 67, no. 266 (April 4, 2016): 22–37. http://dx.doi.org/10.1093/pq/pqw028.

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Goud, B. Srikanth, Ch Rami Reddy, Mohit Bajaj, Ehab E. Elattar, and Salah Kamel. "Power Quality Improvement Using Distributed Power Flow Controller with BWO-Based FOPID Controller." Sustainability 13, no. 20 (October 11, 2021): 11194. http://dx.doi.org/10.3390/su132011194.

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Анотація:
The integration of hybrid renewable energy sources (HRESs) into the grid is currently being encouraged to meet the increasing demand for electric power and reduce fossil fuels which are causing environmental-related problems. Integration of HRESs into the grid can create some power quality (PQ) problems. To mitigate PQ problems and improve the performance of grid-connected HRESs some flexible devices should be used. This paper presents a distributed power flow controller (DPFC), as a type of flexible device to mitigate some PQ problems, including voltage sag, swell, disruptions, and eliminating the harmonics in a hybrid power system (HPS). The HPS presented in this work comprises a photo voltaic (PV) system, wind turbine (WT) and battery energy storage system (BESS). As a result, black widow optimization (BWO) with DPFC with real and reactive power (DPFC-PQ) is built in this paper to solve the PQ issues in HRES systems. The main aim of the work is to mitigate PQ problems and compensate for load demand in the HRES scheme. The controller used to drive this DPFC-PQ is a fractional-order PID (FOPID) controller optimized by the black widow optimization (BWO) technique. To assess the capability of BWO in fine-tuning the FOPID controller parameters, twelve optimization techniques were presented: P&O, PSO, Cuckoo, GA, GSA, BBO, Whale, ESA, RFA, ASO, and EVORFA. Additionally, a comparison between the FOPID controller and the classical PI controller is introduced. The results showed that the proposed BWO-FOPID controller for DFPC had mitigated the PQ problems in grid-connected HRESs. The system’s performance with the presented BWO-FOPID controller is compared with eleven optimization techniques used to optimize the FOPID controller and also compared with the conventional PI controller. The design of the proposed system is implemented in the MATLAB/Simulink platform and performances were analyzed.
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Bhende, C. N., A. Kalam, and S. G. Malla. "Mitigation of Power Quality Problems in Grid-Interactive Distributed Generation System." International Journal of Emerging Electric Power Systems 17, no. 2 (April 1, 2016): 165–72. http://dx.doi.org/10.1515/ijeeps-2015-0163.

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Abstract Having an inter-tie between low/medium voltage grid and distributed generation (DG), both exposes to power quality (PQ) problems created by each other. This paper addresses various PQ problems arise due to integration of DG with grid. The major PQ problems are due to unbalanced and non-linear load connected at DG, unbalanced voltage variations on transmission line and unbalanced grid voltages which severely affect the performance of the system. To mitigate the above mentioned PQ problems, a novel integrated control of distribution static shunt compensator (DSTATCOM) is presented in this paper. DSTATCOM control helps in reducing the unbalance factor of PCC voltage. It also eliminates harmonics from line currents and makes them balanced. Moreover, DSTATCOM supplies the reactive power required by the load locally and hence, grid need not to supply the reactive power. To show the efficacy of the proposed controller, several operating conditions are considered and verified through simulation using MATLAB/SIMULINK.
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Karthik, N., Shaik Abdul Gafoor, and M. Surya Kalavathi. "Classification of Power Quality Problems by Wavelet Fuzzy Expert System." Advanced Materials Research 463-464 (February 2012): 1573–78. http://dx.doi.org/10.4028/www.scientific.net/amr.463-464.1573.

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Анотація:
Electric power quality, which is a current interest to several power utilities all over the world, is often severely affected by harmonics and transient disturbances. There is no unique model which can assess the power quality problem and to identify and classify them properly. Existing automatic recognition methods need improvement in terms of their versatility, reliability, and accuracy. The FUZZY LOGIC based tools have been applied for the PQ classification. This paper addresses Power quality problem classification by wavelet and fuzzy expert system. Major Key issues and challenges related to these advanced techniques in automatic classification of PQ problems are highlighted. New intelligent system technologies using DSP, expert systems, AI and machine learning provide some unique advantages in intelligent classification of PQ distortions
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Dhanakodi.V, N.Balachandar, and M.Gayathri. "Power Quality Monitoring and Feedback Control for Hybrid Renewal Energy System using Meta Heuristic Optimization Technique." International Journal of Scientific Methods in Intelligence Engineering Networks 01, no. 04 (2023): 33–44. http://dx.doi.org/10.58599/ijsmien.2023.1404.

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Анотація:
Solar and wind energy are becoming more popular. Hybrid Renewable Energy System (HRES) is a fast-growing power industry segment. Power quality (PQ) issues have increased as renewable energy has increased in the electricity supply. This study will help electrical engineers identify power quality (PQ) disruptions from hybrid renewable power sources like solar and wind. The investigation will predict powergeneration-induced PQ problems. A self-contained Hybrid Renewable Energy System (HRES) is the project’s main goal. We will collect and analyses energy system data using Grey Wolf Optimization to improve mitigation and reduce PQ interruptions. The suggested technique analyses live data from several sources and historical data in many formats. To prevent problems, the hardware’s controllers will receive the data. Algorithms and designers will improve system efficiency and design ability. The monitoring system will predict PQ disturbances caused by electricity generation from different energy sources. The suggested device labels PQ disturbances by impact.
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Mewes, Ricarda, Boris Friele, and Evert Bloemen. "Validation of the Protect Questionnaire: A tool to detect mental health problems in asylum seekers by non-health professionals." Torture Journal 28, no. 2 (July 28, 2018): 56–71. http://dx.doi.org/10.7146/torture.v28i2.106884.

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Introduction: Prevalence rates of trauma-related mental disorders such as posttraumatic stress disorder (PTSD) or major depression (MD) are high in asylum seekers. The PROTECT Questionnaire (PQ) was designed to detect indications of those disorders in asylum seekers. Empirical data are needed to evaluate the PQ psychometrically. The objective of this study is to investigate the reliability, validity, sensitivity, and specificity of the PQ. Method: The PQ and validated questionnaires for PTSD (Posttraumatic Diagnostic Scale, PDS) and depression (Patient Health Questionnaire-9, PHQ- 9) were filled in by a sample of recently arrived asylum seekers in Germany (n=141). A sub-sample of 91 asylum seekers took part in a structured clinical interview to diagnose PTSD or MD (SCID-I). Results: The PQ showed a one-factor structure and good reliability (Cronbach’s ⍺= .82). It correlated highly with the PDS and the PHQ-9 (rs=.53-.77; ps≤.001). Diagnostic accuracy with regard to PTSD (AUC=.74; SE=.06; p<.001; 95%-CI=.63-.84) and MD (AUC=.72; SE=.06; p<.001; 95%-CI=.61- .83) was adequate, suggesting an optimal cut-off of 8 or 9. By categorizing participants into a low- and high-risk category, the PQ differentiated well between asylum seekers who fulfilled a PTSD or MD diagnosis and those who did not. Discussion: The results support the use of the PQ as a reliable and valid instrument for the purpose of detecting signs and symptoms of the two most common mental disorders in asylum seekers. Persons found to be at risk of mental disorders should be referred to a clinical diagnostic procedure.
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Jiang, Shulun, Jian Yang, and Di-an Fang. "Transcriptome changes of Takifugu obscurus liver after acute exposure to the oxygenated-PAH 9,10-phenanthrenequione." Physiological Genomics 52, no. 8 (August 1, 2020): 305–13. http://dx.doi.org/10.1152/physiolgenomics.00022.2020.

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Анотація:
Contamination with polycyclic aromatic hydrocarbons (PAHs) causes noticeable ecological problems in aquatic ecosystems. 9,10-Phenanthrenequione (9,10-PQ) is an oxidized PAH and is highly toxic to aquatic animals. However, the effects of 9,10-PQ on the molecular metabolism of fish remain largely unknown. In this study, Takifugu obscurus juveniles were acutely exposed to 44.30 µg/L 9,10-PQ for 3 days. The transcriptome profile changes in their livers were compared between the 9,10-PQ treatment group and the control using T. rubripes as the reference genome. The results identified 22,414 genes in our transcriptome. Among them, 767 genes were differentially expressed after exposure to 9,10-PQ, which enriched 16 KEGG pathways. Among them, the glycolysis, phagosome, and FOXO signaling pathways were significantly activated in 9,10-PQ treatment compared with the control. These data indicate that 9,10-PQ increased the glycolysis capacity to produce more energy for resistance and harmed immune function. Moreover, several genes related to tumorigenesis were significantly upregulated in response to 9,10-PQ, displaying the carcinogenic toxicity of 9,10-PQ to T. obscurus. Genes in steroid biosynthesis pathways were downregulated in the 9,10-PQ treatment group, suggesting interference with the endocrine system. Overall, these findings provide information to help evaluate the environmental risks that oxygenated-PAHs present to T. obscurus.
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Дисертації з теми "PQ PROBLEMS"

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Nintai, Moses Nunyi. "Mapping transference : problems of African literature and translation from French into English." Thesis, University of Warwick, 1993. http://wrap.warwick.ac.uk/36074/.

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Анотація:
Although a number of African literary works have been translated from French into English since the middle of this century, research and debate on their translation has remained scanty, fragmentary, and scattered in diverse learned journals and other short publications. This thesis seeks to broaden the scope of research by mapping out aspects of transference in translation in terms of analysis and transfer strategies that have been, or could be, used. A selection of major translated works have been compared with their originals, to give textual examples indicative of transfer strategies. Current issues in African literature as well as typical features of the literature in French and English have been explored in order to examine differences between them and English and French literatures. The implications of these differences (at the levels of content, cultural setting, peculiar use of English and French, and the target audience) for translation are considered, and a brief historical survey of the translation of African literature provides insights into how translators have approached, and continue to approach, literary texts as well as cope with their target readership. Furthermore, dominant trends in literary translation studies (mainly in the West) are explored to determine if, and in what ways, they relate to translation studies in Africa. The analysis of transfer strategies focuses on the distinctive features of francophone African literary texts, drawing on relevant Western literary translation theories and models, on African literary theory and criticism, as well as on other disciplines likely contribute to an informed understanding of the texts. Finally, a case study applies the analysis to a text which is translated, and transfer strategies discussed.
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CHITTORA, PRAKASH. "ANALYSIS AND CONTROL OF SHUNT COMPENSATOR IN DISTRIBUTION SYSTEM." Thesis, 2018. http://dspace.dtu.ac.in:8080/jspui/handle/repository/16436.

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Анотація:
Electrical Power distribution systems suffer from power quality (PQ) problems such as poor power factor, load unbalancing, harmonics, distortion in voltage etc. The contribution of non linear loads incorporating power electronics devices viz. switch mode power supply, variable frequency drive (VFD), lighting loads (CFL, LED) etc. in power distribution systems is high. This leads to higher PQ problems into the system such as harmonics injection in voltage and current, high neutral current etc. Since the continued presence of PQ problems deteriorates the quality of power at the end user level, hence it becomes important to find solutions to overcome power quality problems. Conventional methods to improve PQ in distribution system include the installation of capacitors, tap changing transformers, reactors, capacitor banks etc. However, these are slow compensation techniques and do not provide active load compensation, so new custom power devices have been designed. Shunt Active Power Filter (SAPF) is one such solution aimed to provide load compensation. The SAPF can mitigate several PQ problems such as load unbalancing, current harmonics, poor power factor of load etc. A SAPF can be realized using Voltage Source Converter (VSC) with a DC link capacitor. Three leg VSC for three-phase, three wire (TPTW) and four leg VSC for three-phase, four wire (TPFW) configuration are conventionally used VSC configurations. TPFW systems may have additional requirement of neutral current compensation due to the presence of unbalanced loads. The SAPF with four legs can be realized for TPFW system, however, the system cost increases. A low cost solution is to use zigzag transformer configuration to mitigate excess neutral current and the conventional TPTW SAPF configuration. v The proposed work has been divided into four parts and deals with compensation in TPTW and TPFW distribution systems, distorted three-phase grid systems and single –phase systems without/ with PV integration. Detailed system design, development and analysis of new control algorithms have been investigated. Simulation as well as experimental results have been analyzed and tabulated with linear as well as non-linear loads. Conventional control techniques viz Synchronous Reference frame Theory (SRFT), Power Balance Theory (PBT) and Instantaneous Reactive Power Theory (IRPT) have been initially tested on the prototype system developed in the laboratory. Three new control algorithms have been developed on TPTW distribution system which include Notch Filter, Kalman-LMS and Hopfield neural network based algorithm. These have been developed and implemented using dSPACE 1104 as Digital Signal Processor (DSP). Various PQ issues such as load unbalancing, current harmonics and supply current power factor have been considered. Detailed simulation results are recorded and verification of these results on the experimental setup is performed. Simulation has been performed in MATLAB/SIMULINK environment. PQ problems in TPFW distribution system have been studied. The control algorithms developed for this system are Self Tuning Filter (STF), Modified Recursive Gauss Newton (MRGN) and Chebyshev polynomial based algorithms. A conventional three leg configuration of VSC has been used as SAPF; however zigzag transformer has been designed and used for neutral current compensation. The experimental setup has been controlled using dSPACE 1104. PQ issues such as load unbalancing, current harmonics, supply current power factor and neutral current compensation have been considered with different loads. Experimental results of all techniques have been analyzed in details. vi In electrical power distribution system, the presence of distortion in the grid voltages is also a major PQ problem. The supply voltages may have high distortion due to presence of large source impedance. The TPFW experimental setup with distorted grid and unbalanced linear and non linear loads has been investigated. PQ issues such as load unbalancing, current harmonics, supply current power factor and neutral current compensation have been mitigated successfully for distorted Point of Common Connection (PCC) voltages. Both simulation and hardware results using Multiple Complex Coefficient Filter (MCCF) and Second Order Generalized Integrator (SOGI) control algorithms have been analyzed and compared. Next, PQ problems in a single phase grid connected system have been analyzed and the system has been developed in the laboratory. Two aspects discussed in this chapter are the integration of PV and mitigation of PQ problems. Three control algorithms viz SRFT, Notch Filter and second order generalized integrator (SOGI) based algorithm have been developed to mitigate PQ problems. Solution of PQ problems in single-phase, TPTW, TPFW distribution systems using different SAPF configurations and new control techniques is the highlight of this thesis work.
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Частини книг з теми "PQ PROBLEMS"

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Paracha, Zahir Javed, and Akhtar Kalam. "Intelligent Techniques for the Analysis of Power Quality Data in Electrical Power Distribution System." In Handbook of Research on Industrial Informatics and Manufacturing Intelligence, 563–75. IGI Global, 2012. http://dx.doi.org/10.4018/978-1-4666-0294-6.ch024.

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Анотація:
This chapter is about the intelligent techniques for the analysis of power quality problems in electrical power distribution system. The problems related with electrical power industry are becoming more widespread, complex, and diversified. The behaviour of power distribution systems can be monitored effectively using artificial intelligence techniques and methodologies. There is a need of understanding the power system operations from power utility perspectives and application of computational intelligence methods to solve the problems of the power industry. The real power quality (PQ) data is taken from a power utility in Victoria Australia. Principal Component Analysis Technique (PCAT) is used to reduce the large number of PQ data attributes of the power distribution system. After the pre-processing of PQ data using PCAT, intelligent computational techniques will be used for the analysis of power quality data. Neural network techniques will be employed to estimate the values of PQ parameters of the power distribution system. The Feed Forward Back Propagation (FFBP) neural network and Recurrent Neural Networks (RNN) are used for intelligent estimation of PQ data. The results obtained through these intelligent techniques are compared with the real data of power utility in Victoria, Australia for stability, reliability and enhanced power systems performance.
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Dekhandji, Fatma Zohra, and Mohamed Cherif Rais. "A Comparative Study of Power Quality Monitoring Using Various Techniques." In Advances in Computer and Electrical Engineering, 259–88. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4027-5.ch011.

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Анотація:
In recent years, power quality (PQ) has become an increasingly major concern for both electric utilities and the end users. Accordingly, the electrical engineering community has to deal with the analysis, diagnosis, and solution of PQ issues using system approach rather than handling these issues as individual problems. This chapter describes the analysis of PQ using advanced signal processing tools represented in Hilbert and wavelet transforms (HT-WT) and artificial intelligence tools represented in artificial neural network and support vector machine (ANN-SVM) for detection and classification of power quality disturbances, respectively. These techniques were successfully simulated using LABVIEW software capabilities. The results of simulation indicate that the signal processing techniques are effective mechanisms to detect and classify power quality disturbances. At the end, the combination of WT as a tool of detection and features extraction with SVM as a classifier tool resulted as the best combination for PQ monitoring system.
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Hasan, Mashhood. "Application of Power Electronics in Power Systems." In Handbook of Research on Power and Energy System Optimization, 322–52. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-3935-3.ch010.

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Анотація:
This chapter introduces the custom power device to solve the various kinds of power quality (PQ) problems. It is generally known as flexible AC transmission system (FACTS) and D-FACTS (FACTs used for low voltage and low current rating in AC distribution system). The D-FACTS are various types like dynamic voltage restore (DVR), static compensator in distribution system (D-STATCOM), and unified power quality conditioner (UPQC). The third one is combination of DVR and D-STATCOM, which is known as UPQC. The UPQC can compensate all the PQ problems. Comprehensive knowledge of UPQC is presented here to understand the trade value of this device. This chapter is organized as follows: The evaluation of power electronic based devices is presented in the background part of this chapter where custom power devices (CPDs) are also discussed. And operating principle with the Matlab model of UPQC and results are presented in the section titled “Working Principle of Unified Power Quality Conditioner (UPQC).” The scope of the one of the functional power electronic based devices are presented in section titled “Scope of UPQC.” At the end, this chapter is concluded.
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Zhang, Ying, Chaopeng Li, Na Chen, Shaowen Liu, Liming Du, Zhuxiao Wang, and Miaomiao Ma. "Semantic-Based Geospatial Data Integration With Unique Features." In Geospatial Intelligence, 254–77. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-8054-6.ch012.

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Анотація:
Since large amount of geospatial data are produced by various sources, geospatial data integration is difficult because of the shortage of semantics. Despite standardised data format and data access protocols, such as Web Feature Service (WFS), can enable end-users with access to heterogeneous data stored in different formats from various sources, it is still time-consuming and ineffective due to the lack of semantics. To solve this problem, a prototype to implement the geospatial data integration is proposed by addressing the following four problems, i.e., geospatial data retrieving, modeling, linking and integrating. We mainly adopt four kinds of geospatial data sources to evaluate the performance of the proposed approach. The experimental results illustrate that the proposed linking method can get high performance in generating the matched candidate record pairs in terms of Reduction Ratio(RR), Pairs Completeness(PC), Pairs Quality(PQ) and F-score. The integrating results denote that each data source can get much Complementary Completeness(CC) and Increased Completeness(IC).
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Zhang, Ying, Chaopeng Li, Na Chen, Shaowen Liu, Liming Du, Zhuxiao Wang, and Miaomiao Ma. "Semantic-Based Geospatial Data Integration With Unique Features." In Innovations, Developments, and Applications of Semantic Web and Information Systems, 393–416. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-5042-6.ch015.

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Анотація:
Since large amount of geospatial data are produced by various sources, geospatial data integration is difficult because of the shortage of semantics. Despite standardised data format and data access protocols, such as Web Feature Service (WFS), can enable end-users with access to heterogeneous data stored in different formats from various sources, it is still time-consuming and ineffective due to the lack of semantics. To solve this problem, a prototype to implement the geospatial data integration is proposed by addressing the following four problems, i.e., geospatial data retrieving, modeling, linking and integrating. We mainly adopt four kinds of geospatial data sources to evaluate the performance of the proposed approach. The experimental results illustrate that the proposed linking method can get high performance in generating the matched candidate record pairs in terms of Reduction Ratio(RR), Pairs Completeness(PC), Pairs Quality(PQ) and F-score. The integrating results denote that each data source can get much Complementary Completeness(CC) and Increased Completeness(IC).
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"Chapter 6. Subtour Cuts and PQ-Trees." In The Traveling Salesman Problem, 159–84. Princeton: Princeton University Press, 2011. http://dx.doi.org/10.1515/9781400841103.159.

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Zhang, Ying, Chaopeng Li, Na Chen, Shaowen Liu, Liming Du, Zhuxiao Wang, and Miaomiao Ma. "Semantic Web and Geospatial Unique Features Based Geospatial Data Integration." In Geospatial Intelligence, 230–53. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-8054-6.ch011.

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Анотація:
Since large amount of geospatial data are produced by various sources and stored in incompatible formats, geospatial data integration is difficult because of the shortage of semantics. Despite standardised data format and data access protocols, such as Web Feature Service (WFS), can enable end-users with access to heterogeneous data stored in different formats from various sources, it is still time-consuming and ineffective due to the lack of semantics. To solve this problem, a prototype to implement the geospatial data integration is proposed by addressing the following four problems, i.e., geospatial data retrieving, modeling, linking and integrating. First, we provide a uniform integration paradigm for users to retrieve geospatial data. Then, we align the retrieved geospatial data in the modeling process to eliminate heterogeneity with the help of Karma. Our main contribution focuses on addressing the third problem. Previous work has been done by defining a set of semantic rules for performing the linking process. However, the geospatial data has some specific geospatial relationships, which is significant for linking but cannot be solved by the Semantic Web techniques directly. We take advantage of such unique features about geospatial data to implement the linking process. In addition, the previous work will meet a complicated problem when the geospatial data sources are in different languages. In contrast, our proposed linking algorithms are endowed with translation function, which can save the translating cost among all the geospatial sources with different languages. Finally, the geospatial data is integrated by eliminating data redundancy and combining the complementary properties from the linked records. We mainly adopt four kinds of geospatial data sources, namely, OpenStreetMap(OSM), Wikmapia, USGS and EPA, to evaluate the performance of the proposed approach. The experimental results illustrate that the proposed linking method can get high performance in generating the matched candidate record pairs in terms of Reduction Ratio(RR), Pairs Completeness(PC), Pairs Quality(PQ) and F-score. The integrating results denote that each data source can get much Complementary Completeness(CC) and Increased Completeness(IC).
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Farid Abidin, Ahmad, and Mohd Abdul Talib Mat Yusoh. "LabVIEW as Power Disturbances Classification Tools." In LabVIEW - A Flexible Environment for Modeling and Daily Laboratory Use. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96079.

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Анотація:
Power disturbances monitoring is one of the important aspects on dealing power quality issue in electrical system. The aims of conducting monitoring process are to identify the real culprit which contribute to the Power Quality (PQ) problem. One of the vital steps during monitoring process is the classifying various type of power disturbance. This classification process is very important to give a right direction towards proposing the correct mitigation technique. In order to produce reliable classification technique, the devices which has a flexibility on accommodating the software and hardware part need to be deployed. The software is need for algorithm development such as signal processing, Artificial Intelligent (AI) as well as statistical analysis. On the hardware part, the device’s ability to acquire the electrical parameter within the electrical system operation is very important. The data acquisition based on the voltage and current is essential to be feed in the classification algorithm in software side. On the other hand, the interfacing devices and data acquisition module need to be developed at the hardware side, LabVIEW manage to accommodate both software and hardware need and further development of the LabVIEW for this purpose will be elaborated in this chapter.
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Tennant, Neil. "Mereology and Fraction Abstraction." In The Logic of Number, 177–94. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780192846679.003.0016.

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Анотація:
The chapter seeks to show how rational numbers—fractions—are entities to which ra tional thinkers are logically entitled. It begins by introducing mereology as part of our conceptual and methodological framework for eventually attaining a grasp of fractions. The basic concepts of mereology are laid out, with their formal notations. The treatment of identity is discussed. Mereology is the theory of the part-whole relation, and is of very low consistency strength; indeed, it is arguably analytically true. Mereological fusion is treated here as an abstraction operator, in this study’s preferred single-barreled fashion, with introduction and elimination rules in free Core Logic. The notion of a dimensional magnitude(such as length) is introduced, along with the correlative notion of dimensional equality (such as line-segment congruence). One can define whole-number multiples of dimensional magnitudes (such as lengths of line segments; or ‘identical’ pizzas). This enables one to address the problem of characterizing what constitutes an equal share of p dimensionally equal items when these are to be divvied up into q dimensionally equal shares. An easy application of fractional abstraction then delivers the rational number pq. The introduction and elimination rules for fractional abstraction furnish easy proof of all instances of Schema Q. One learns too why q cannot be 0, and why the rational number n1is the natural number n.
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Тези доповідей конференцій з теми "PQ PROBLEMS"

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Bläsius, Thomas, and Ignaz Rutter. "Simultaneous PQ-Ordering with Applications to Constrained Embedding Problems." In Proceedings of the Twenty-Fourth Annual ACM-SIAM Symposium on Discrete Algorithms. Philadelphia, PA: Society for Industrial and Applied Mathematics, 2013. http://dx.doi.org/10.1137/1.9781611973105.74.

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Janson, K., J. Jarvik, L. Kutt, and A. Soosalu. "Improvement of voltage transformers overvoltage problems in MV networks." In 2008 Power Quality and Supply Reliability Conference (PQ). IEEE, 2008. http://dx.doi.org/10.1109/pq.2008.4653769.

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Jalakas, T., H. Molder, and M. Egorov. "EMI reduction problems in power converters with 6.5 kV IGBTs." In 2008 Power Quality and Supply Reliability Conference (PQ). IEEE, 2008. http://dx.doi.org/10.1109/pq.2008.4653766.

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Nicolae, Petre-Marian, Dinut-Lucian Popa, and Marian-Stefan Nicolae. "PQ versus EMC problems at a static excitation system in a power group." In 2014 International Symposium on Electromagnetic Compatibility - EMC EUROPE. IEEE, 2014. http://dx.doi.org/10.1109/emceurope.2014.6930983.

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5

Korovkin, Nikolay, George Greshnyakov, and Simon Dubitsky. "Multiphysics approach to the boundary problems of power engineering and their application to the analysis of load-carrying capacity of power cable line." In 2014 Electric Power Quality and Supply Reliability Conference (PQ). IEEE, 2014. http://dx.doi.org/10.1109/pq.2014.6866837.

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6

Bhavani, R., and N. Rathina Prabha. "A hybrid classifier for power quality (PQ) problems using wavelets packet transform (WPT) and artificial neural networks (ANN)." In 2017 IEEE International Conference on Intelligent Techniques in Control, Optimization and Signal Processing (INCOS). IEEE, 2017. http://dx.doi.org/10.1109/itcosp.2017.8303073.

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7

Nicolae, Petre-Marian, Dinut-Lucian Popa, Marian-Stefan Nicolae, and Ileana-Diana Nicolae. "PQ and EMC problems from the connection at the supplying network induced by an AC-DC-AC converter." In 2014 16th International Conference on Harmonics and Quality of Power (ICHQP). IEEE, 2014. http://dx.doi.org/10.1109/ichqp.2014.6842819.

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8

Yilmaz, Ilker, Emre Durna, and Muammer Ermis. "Design and implementation of a hybrid system for the mitigation of PQ problems of medium-frequency induction steel-melting furnaces." In 2015 IEEE Industry Applications Society Annual Meeting. IEEE, 2015. http://dx.doi.org/10.1109/ias.2015.7356883.

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9

S. Salles, Rafael, Gabriel C. S. Almeida, Leandro R. M. Silva, Carlos A. Duque, and Paulo F. Ribeiro. "Visualization of Quality PerformanceParameters Using Wavelet Scalograms Images for Power Systems." In Congresso Brasileiro de Automática - 2020. sbabra, 2020. http://dx.doi.org/10.48011/asba.v2i1.1497.

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Анотація:
Power quality problems are not new to power systems, but they cannot be overlooked. In the context of Smart Grids, power systems are undergoing a transformation characterized by the high penetration of renewable sources and electronic devices in the grids, in addition to greater computerization of operations. Thus, alternatives in the representation and visualization of these integrated quality parameters become more and more necessary, both for a better understanding of these phenomena and for advanced applications with the use of images.With this in mind, this paper aims to present an alternative for visualizing PQ disturbances through 2-D images from scalograms based on the continuous wavelet transform (CWT) and multiresolution analysis. For this, signals from three dierent sources, mathematical equations, models of transmission anddistribution of energy in MATLAB / Simulink, and real signals from a database were used. For the creation of the scalogram images, the signal processing technique, and the use of a color map were used to show the performance. The results showed the eciency of the method for visualization and characterization of addressed disturbances. The enkaptics phenomena were also highlighted, which show the simultaneity and relationship between dierent types of signal variation. The work contributes to using signals from dierent sources, synthetic, from simulation or real signals, to oer a methodology that describes tools for a method of visualization.
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Dmitriev, N. I., V. I. Burkov, and G. R. Lokshin. "Possibility of phase problem solution via a programmable optical signal processor." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/oam.1989.thll3.

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Анотація:
We have considered an original and a simple phase retrieval method using a programmable optical signal processor. The simplest processor allowing one to measure the phase ϕ(x, y) consists of a controlled spatial light modulator (CSLM), lens, photodetector, ADC, and computer. The spatial modulator (for example, liquid crystal modulator) is set immediately in front of the lens. In its focal plane there is a point photodetector which, by means of an ADC, is connected with the computer intended for handling the information obtained and controlling the CSLM. Complex field E(x, y) = |e(x, y)| expiϕ(x, y) belongs to the function class represented by the Fourier series where { mn (y)} is the orthogonal basis. If the CSLM is programmed for generation transmission according to {ψ mn (x, y)}, {ψ pq (x, y) + ψ mn (x, y)} m ≠ p, n ≠ q and {iψ pq (x, y) + ψ mn (x, y)} m ≠ p, n ≠ q [where ψpq(x, y) is a reference function], then, via the point photodetector, exhaustive information about complex array {c mn } can be obtained. In this case the phase retrieval is performed by the computer.
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