Academic literature on the topic 'NPD DETECTOR'

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Journal articles on the topic "NPD DETECTOR"

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Rao, Yuan, and Arno de Klerk. "Nitrogen-containing aromatic compounds: quantitative analysis using gas chromatography with nitrogen phosphorus detector." Applied Petrochemical Research 11, no. 2 (March 6, 2021): 129–36. http://dx.doi.org/10.1007/s13203-021-00265-z.

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AbstractThe nitrogen-containing aromatic compounds found in the petrochemical industry are varied and extend beyond classes such as the anilines, pyrroles and pyridines. Quantification of these nitrogen-containing compounds that may occur in complex mixtures has practical application for quality assurance, process development and the evaluation of conversion processes. Selective detection of nitrogen-containing species in complex mixtures is possible by making use of gas chromatography coupled with a nitrogen phosphorous detector (GC-NPD), which is also called a thermionic detector. Despite the linearity of the NPD response to individual nitrogen-containing compounds, the response factor is different for different compounds and even isomers of the same species. Quantitative analysis using an NPD requires species-specific calibration. The reason for the sensitivity of the NPD to structure is related to the ease of forming the cyano-radical that is ionized to the cyanide anion, which is detected. The operation of the NPD was related to the processes of pyrolysis and subsequent ionization. It was possible to offer plausible explanations for differences in response factors for isomers based on pyrolysis chemistry. Due to this relationship, the NPD response can in the same way be used to provide information of practical relevance beyond its analytical value and a few possible applications were outlined.
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Satto, Isao, Sadaji Yamada, Harumi Oshtma, Yoshttomo Ikai, Hisao Oka, and Junko Hayakawa. "Analysis of Methyl Isothiocyanate in Wine by Gas Chromatography with Dual Detection." Journal of AOAC INTERNATIONAL 77, no. 5 (September 1, 1994): 1296–99. http://dx.doi.org/10.1093/jaoac/77.5.1296.

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Abstract Methyl isothiocyanate (MITC) was extracted from a 5 mL wine sample with 2 mL dichloromethane, and the extract was washed with 5% sodium chloride solution. MITC was determined by gas chromatography with a dual nitrogen-phosphorus detector (NPD) and a flame photometric detector (FPD, S mode) (DB-210 column, 30 m × 0.53 mm id, column temperature, 70°C). The limit of detection and quantitation of MITC with NPD–GC were 0.003 and 0.01 ppm, respectively. Average recoveries of MITC added to wine at 1 and 0.1 ppm were over 95%. This method is simple and rapid for routine analysis of MITC in wine.
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Frenich, Antonia Garrido, Maria Del Carmen Pablos Espada, Jose Luis Martínez Vidal, and Luis Molina. "Broad-Spectrum Determination of Pesticides in Groundwater by Gas Chromatography with Electron Capture Detection, Nitrogen–Phosphorus Detection, and Tandem Mass Spectrometry." Journal of AOAC INTERNATIONAL 84, no. 6 (November 1, 2001): 1751–62. http://dx.doi.org/10.1093/jaoac/84.6.1751.

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Abstract Gas chromatography with electron capture detector (ECD), nitrogen–phosphorus detector (NPD), and tandem mass spectrometry (MS/MS) was used to identify 36 pesticides, widely used to control various pest and diseases in vegetables, in water after a preconcentration step on C18 cartridges. The recoveries obtained ranged from 70 to 135% at a fortification level of 100 ng/L with relative standard deviations of <36.2%. The limits of detection and quantitation were ≤48 and ≤160 ng/L, respectively. Important advantages of MS/MS over ECD and NPD in the determination of pesticides are also presented. The proposed analytical methodology was applied to the determination of pesticides in groundwater samples from an agricultural area, the Campo de Dalías (Almería, Spain). The most frequently encountered pesticides were endosulfan sulfate and metalaxyl, whereas the pesticide found at the highest concentration was fenamiphos.
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Paulsdorf, Jürgen, Hans-Dieter Wiemhöfer, Andrej Orinák, Petr Zámostný, Zdeněk Bělohlav, and David Baxter. "Application of pyrolysis-capillary gas chromatography with NPD detection in thermal degradation of polyphosphazenes study." Open Chemistry 5, no. 1 (March 1, 2007): 271–90. http://dx.doi.org/10.2478/s11532-006-0047-8.

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AbstractPolyphosphazenes represent a unique class of polymers with a backbone composed of alternating phosphorous and nitrogen atoms. The thermal behaviour and decomposition of a variety of polyphosphazenes depends on the type of side groups present. Especially those that bear aryloxy side groups, possess a high temperature stability as well as excellent flame resistance. Pyrolysis-capillary gas chromatography has been used in a study of three polyphosphazene samples for thermal stability characterisation. Degradation products were detected with three single detectors for flame ionisation (FID), nitrogen-phosphorous sensitivity (NPD) and mass spectrometry (MSD) at different pyrolysis temperatures ranging from 300°C up to 800°C. The NPD responses for phosphorous or nitrogen fragments of polyphosphazenes have been used for the construction of degradation product schemes and the examination of the thermal stability of the polyphosphazene’s backbone. Partial identification of the degradation products present in the gaseous phase was achieved by MSD. The polyphosphazenes thermal degradation conversion rates were at a maximum at 450–500°C. At various pyrolysis temperatures, the calculated N/P peak area ratio is a function of the degree of polyphosphazene-N=P-chain degradation, and reflective of the nitrogen — phosphorous detector sensitivity. NPD proved to be suitable tool for characterization of polyphospazene thermal stability.
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Kim, Sim Hae, Jun-Ho Hwang, and Kwang-Geun Lee. "Analysis of acrylamide using gas chromatography-nitrogen phosphorus detector (GC-NPD)." Food Science and Biotechnology 20, no. 3 (June 2011): 835–39. http://dx.doi.org/10.1007/s10068-011-0116-4.

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Abdel-Rehim, Mohamed, and Moustapha Hassan. "Effect of ammonia on the response of the nitrogen phosphorus detector (NPD)." Journal of Microcolumn Separations 6, no. 4 (July 1994): 369–72. http://dx.doi.org/10.1002/mcs.1220060405.

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Soo, V. A., R. J. Bergert, and D. G. Deutsch. "Screening and quantification of hypnotic sedatives in serum by capillary gas chromatography with a nitrogen-phosphorus detector, and confirmation by capillary gas chromatography-mass spectrometry." Clinical Chemistry 32, no. 2 (February 1, 1986): 325–28. http://dx.doi.org/10.1093/clinchem/32.2.325.

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Abstract We describe a quantitative screen for hypnotic-sedative drugs in which we use capillary gas chromatography with a nitrogen-phosphorus detector (GC/NPD) as the primary method and capillary gas chromatography-mass spectrometry (GC-MS) for confirmation. GC retention times of the acid-extracted underivatized drugs were stable (CVs less than 1%), and the detector response varied linearly over a 20-fold concentration range with a mean correlation coefficient for 11 drugs of 0.989. The limits of detection were satisfactory (0.5 mg/L in a 0.5-mL serum sample and 1-microL injection volume), as were precision (average CV 5.2% within day, 6.4% between day). The complementary use of capillary GC-MS not only unambiguously confirms presumptive peaks identified by GC, but also prevents reports of false positives and identifies compounds not included in the quantitative GC screen that may be listed in the GC-MS library.
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Alnedhary, Anass A., Abdualqawi A. Numan, Mahfoudh M. AL - Hammadi, and Taiseer H. Al - Hoded. "Optimization, Validation and Application of Quantitative Method for the Determination of Acrylamide in Potato Chips Samples in Yemen Using GC-NPD." Pakistan Journal of Analytical and Environmental Chemistry 24, no. 1 (June 27, 2023): 63–73. http://dx.doi.org/10.21743/pjaec/2023.06.06.

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Over the last two decades, numerous analytical methods for determining acrylamide concentration in a wide range of food products have been developed. Some studies focused on the methods of extracting acrylamide from complex food matrices. In the present study, solid Phase Extraction (SPE) and Gas Chromatography-Nitrogen Phosphorus Detector (GC-NPD) analysis were employed to develop a simple and cost-effective acrylamide determination method. Method validation and optimization steps were carried out and used to determine acrylamide concentrations in potato chips purchased from Yemeni markets. In the concentration range of 0.1- 5 ppm, the validated method demonstrated good sensitivity within a 0.012 ppm limit of detection (LOD) and an excellent linearity of 0.996 correlation coefficient. Eighteen samples of potato chips purchased from local markets in Sana'a, Yemen, were analyzed using this method. Three of the 18 samples of interest contained various acrylamide concentration levels of 879.4, 795.6, and 754.7 ppb. These were higher than the EU Commission's indicative value for the acrylamide in potato chips (750 ppb). As a result, the optimized GC-NPD protocol proved to be useful for the acrylamide analysis, paving the way for the development of an acrylamide quantification prescreening tool in the food industry.
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Wang, Shiyu, Zhaohui Ma, Junnan Zhang, Wentao Jiao, Zhirui Qin, Qianhui Yuan, Chengcheng Xie, Wenyong Wu, and Patrick Christopher Wilson. "Structure–Biodegradability Relationship of Nonylphenol Isomers in Two Soils with Long-Term Reclaimed Water Irrigation." Water 14, no. 8 (April 13, 2022): 1258. http://dx.doi.org/10.3390/w14081258.

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Nonylphenol (NP), as one of the typical endocrine disrupter chemicals (EDCs), has a high detection concentration and frequency in reclaimed water. This research focused on the degradation of NP isomers in two typical reclaimed water irrigation fields in Daxing, China, and Florida, USA. The results showed that the half-lives of NP isomer degradation in the soil of China and Florida were 2.03–8.66 d and 5.16–11.83 d, respectively. The degradation of NP isomers was structure-specific. Isomers of NP5, NP2, NP11, and NP3 had the highest degradation rates in the two soils; NP12, NP7, and NP6 were the isomers with medium degradation rates; and NP4, NP1, NP10, NP9, and NP8 had the slowest degradation rates. Steric hindrance and mean information index for the magnitude of distance (IDWbar) were found to be the better indexes for measuring the degradation of NP isomers compared with the length of the side chain, the type of the substitute, and the molecular connectivity. This study offers insights into the characteristics of NP isomers and two reliable indicators for measuring the degradation of NP isomers, which could provide data support for the environmental fate and the health risk assessment of NP in the future.
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Christen, Philippe, Stefan Bieri, and Orlando Muñoz. "Characterization of Positional and Configurational Tropane Alkaloid Isomers by Combining GC with NPD, MS and FTIR." Natural Product Communications 4, no. 10 (October 2009): 1934578X0900401. http://dx.doi.org/10.1177/1934578x0900401006.

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A purified stem bark extract from Schizanthus grahamii was analyzed by combining capillary gas chromatography with a selective nitrogen phosphorus detector, mass spectrometry and Fourier transform infrared spectroscopy. Several positional and configurational tropane isomers were detected and their structural elucidation was tentatively determined based on mass spectra and confirmed by vapor phase infrared spectra. Electron impact mass spectra of the isomeric alkaloids were virtually superimposable, whereas the corresponding infrared spectra differed markedly. Retention indices were established under isothermal and temperature program conditions for further peak assignment and identification. In order to point out possible artifacts in the hot and surface-active injection port, different sample introduction techniques were evaluated, namely split, splitless and on-column injections.
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Dissertations / Theses on the topic "NPD DETECTOR"

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Vojáček, Cyril. "Rozpoznání obličeje." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2014. http://www.nusl.cz/ntk/nusl-236143.

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This thesis is about face detection and recognition from video. Main emphasis is on computational speed, so it can be used for a real-time processing. Begining of this work focus on different approaches for detection and object recognition. Afterwards is explained the main principle of methods used for the final application. Next part is about design and implementation of this methods and conclusion is about the testing results of designed application.
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Ru, Jifeng. "Adaptive estimation and detection techniques with applications." ScholarWorks@UNO, 2005. http://louisdl.louislibraries.org/u?/NOD,285.

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Thesis (Ph. D.)--University of New Orleans, 2005.
Title from electronic submission form. "A dissertation ... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Engineering and Applied Science"--Dissertation t.p. Vita. Includes bibliographical references.
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Maschio, Maria Celeste. "Performance evaluation of detector for digital radiography." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8317/.

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Lo scopo di questo lavoro è la caratterizzazione fisica del flat panel PaxScan4030CB Varian, rivelatore di raggi X impiegato in un ampio spettro di applicazioni cliniche, dalla radiografia generale alla radiologia interventistica. Nell’ambito clinico, al fine di una diagnosi accurata, è necessario avere una buona qualità dell’immagine radiologica mantenendo il più basso livello di dose rilasciata al paziente. Elemento fondamentale per ottenere questo risultato è la scelta del rivelatore di radiazione X, che deve garantire prestazioni fisiche (contrasto, risoluzione spaziale e rumore) adeguati alla specifica procedura. Le metriche oggettive che misurano queste caratteristiche sono SNR (Signal-to-Noise Ratio), MTF (Modulation Transfer Function) ed NPS (Noise Power Spectrum), che insieme contribuiscono alla misura della DQE (Detective Quantum Efficiency), il parametro più completo e adatto a stabilire le performance di un sistema di imaging. L’oggettività di queste misure consente anche di mettere a confronto tra loro diversi sistemi di rivelazione. La misura di questi parametri deve essere effettuata seguendo precisi protocolli di fisica medica, che sono stati applicati al rivelatore PaxScan4030CB presente nel laboratorio del Centro di Coordinamento di Fisica Medica, Policlinico S.Orsola. I risultati ottenuti, conformi a quelli dichiarati dal costruttore, sono stati confrontati con successo con alcuni lavori presenti in letteratura e costituiscono la base necessaria per la verifica di procedure di ottimizzazione dell’immagine radiologica attraverso interventi sul processo di emissione dei raggi X e sul trattamento informatico dell’immagine (Digital Subtraction Angiography).
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Falco, Tony. "MTF, NPS and DQE analysis of portal metal-platefilm detectors." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23885.

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Previous studies of modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) of metal-plate/film portal detectors have been performed on limited combinations of front and back metal-plates. We report on these parameters for an extensive set of forty-nine front-back metal-plate combinations. The portal detector consists of a double emulsion RP (Kodak localization therapy) film placed between metal-plates: Al, Cu, brass and Pb of thicknesses varying from 0.30 to 4.80 mm. Radiation sources included a Theratron Co-60 unit, and a Varian Clinac-18 linear accelerator delivering a polyenergetic 10 MV X-ray spectrum. In terms of the absolute efficiency of the detectors, the best DQE is obtained with the detector consisting of a 1.75 mm Cu front plate and a 1.62 mm Al back plate for the Clinac-18, and with the detector consisting of a 0.95 mm Cu front plate and a 0.80 mm Cu or a 1.62 mm Al back plate for the Co-60 gamma ray source.
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Dias, Pedro Carvalhaes 1983. "Um novo sensor de umidade de solo de pulso de calor de alta sensibilidade, baseado em um único transistor bipolar de junção npn = A novel high sensitivity single probe heat pulse soil moisture sensor based on a single npn bipolar junction transistor = A novel high sensitivity single probe heat pulse soil moisture sensor based on a single npn bipolar junction transistor." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261867.

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Orientador: Elnatan Chagas Ferreira
Texto em inglês
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
Made available in DSpace on 2018-08-20T11:54:01Z (GMT). No. of bitstreams: 1 Dias_PedroCarvalhaes_M.pdf: 7362254 bytes, checksum: dd839cf652cbbda17a2a5d9b6cecbdc3 (MD5) Previous issue date: 2012
Resumo: A constante preocupação em aumentar a produtividade das plantações de uma forma sustentável e otimizando o uso dos insumos agrícolas (água, fertilizantes, pesticidas e produtos para correção do PH) levou ao desenvolvimento da agricultura de precisão, que permite determinar a quantidade correta de insumos para cada região do solo (tipicamente um hectare), evitando o desperdício. Sensores de umidade de solo de baixo custo e fácil aplicação no campo são fundamentais para permitir um controle preciso da atividade de irrigação, sendo que os sensores que melhor atendem estes requisitos são os chamados sensores de dissipação de calor ou sensores de transferência de calor. Estes sensores, entretanto, apresentam um problema de baixa sensibilidade na faixa de umidade mais importante para as plantas (umidade de solo 'teta'v variando entre 5% e 35%), pois, para cobrir esta variação de 30% em 'teta'v com resolução de 1%, é necessário medir variações de temperatura de aproximadamente 0,026 ºC nos sensores de pulso de calor a duas pontas e 0,05 ºC para os sensores de pulso de calor de ponta simples. Neste trabalho foi desenvolvido um novo sensor de umidade de solo do tipo pulso de calor de ponta simples, baseado em um único elemento: um transistor bipolar de junção npn, que é usado tanto como aquecedor e como sensor de temperatura de alta precisão. Resultados experimentais, obtidos em medidas realizadas através de uma técnica de interrogação especialmente desenvolvida para este novo sensor mostram que neste trabalho foi possível obter uma sensibilidade cerca de uma ordem de grandeza maior do que nos sensores de pulso de calor com uma ponta e cerca de 20 vezes maior do que nos sensores de pulso de calor de duas pontas. Outra vantagem da técnica desenvolvida é que o aumento da sensibilidade não é obtido às custas do aumento da corrente drenada da bateria para aquecer o sensor. No sensor desenvolvido é utilizada uma corrente de apenas 6 mA para gerar o aquecimento (com energia dissipada de 1,5 J), enquanto que que os sensores de pulso de calor com ponta simples requerem cerca de 50 mA (com 2,4 J de energia dissipada) para operar. Os sensores de pulso de calor de ponta dupla também são fabricados com resistores que requerem cerca de 50 mA para o aquecimento (0.8 J de energia dissipada) para operar corretamente
Abstract: The concern regarding sustainable development and crop inputs optimization (such as water, fertilizers, pesticides and soil PH correction products) has led to the development of the precision agriculture concept, that allows to determine the exact amount of each input required on each ground section (typically one hectare), avoiding waste of inputs. Low-cost and easily handled soil moisture sensors are very important for allowing a precise irrigation control. The class of sensors which fulfill those requirements are the heat transfer sensors, where there are basically two types of devices: dual (or multi) probe heat pulse sensors and single probe heat pulse sensors. However, these sensors have a low sensitivity in the most important range of soil humidity 'teta'v for plants (usually from 5% ? 'teta'v ? 35%). To cover this 30% soil humidity range with 1% resolution it is necessary to measure temperature with a resolution of 0,026 ºC in the dual/multi probe heat pulse sensors and 0,05 ºC in the single probe heat pulse sensor. In this work it was developed a new type of single probe heat pulse sensor, comprised of a single element: an npn junction bipolar transistor, that plays the role of both the heating element and a high accuracy temperature sensor. Experimental results, obtained through an interrogation technique especially developed for this sensor, show sensitivity about one order of magnitude greater than the typical sensitivity of the single probe heat pulse sensors and 20 times greater than dual probe heat pulse sensors. Another great advantage of the developed interrogation technique is that the increase in sensibility is not obtained through a higher current being drained from the batteries that power the sensor. The developed sensor operates at a much lower current level than the other sensors, draining only 6 mA from the battery (with an energy of 150 mW). The single probe heat pulse sensor requires 50 mA and 1.5 J of energy to operate, whilst the dual probe heat pulse sensors are manufactured with resistors which also drain 50 mA from the battery with 0.8 J of dissipated energy
Mestrado
Eletrônica, Microeletrônica e Optoeletrônica
Mestre em Engenharia Elétrica
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Rosek, Alyssa. "Expression of Epstein-Barr virus proteins and their detection by IgG antibodies." OpenSIUC, 2018. https://opensiuc.lib.siu.edu/theses/2460.

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Epstein-Barr virus, or EBV, is a human herpesvirus that is nearly universally present in most of the human population. The infection rate in adults is quickly approaching an astonishing 95% worldwide. While the most common clinical manifestation of EBV infection is infectious mononucleosis, there are multiple malignancies strongly associated with the virus, such as nasopharyngeal carcinoma (NPC). A contemporary problem in public health is the scarcity of markers to predict the development of EBV-associated malignancies, which prevents a possible cure or a suitable treatment. Of the approximately 85 proteins that the virus expresses, EBV serological tests rely on detection of antibodies against only three antigens: BFRF3 (viral capsid antigen or VCA), BMRF1 (early antigen or EA), and BKRF1 (nuclear antigen or NA). Antibodies against two of these antigens, VCA and NA, are produced by almost all EBV carriers for their entire lifetime, and so detection of these antibodies can make it difficult to differentiate between non-cancerous EBV carriers and EBV-associated cancer patients. To address this problem, the project aimed to identify a set of markers to diagnose NPC and treat it. To test this, 3 EBV genes were cloned with a 3X FLAG-tag into a mammalian expression vector, then expressed and detected by immunoblotting with a monoclonal FLAG antibody and each of the 9 human serum samples used in this study. Our results were generally inconclusive, and further studies are warranted to explore possible diagnostic and prognostic biomarkers.
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Melvin, James E. "AUV fault detection using model based observer residuals." Thesis, Monterey, Calif. : Naval Postgraduate School, 1998. http://bosun.nps.edu/uhtbin/hyperion-image.exe/NPS-ME-98-004.pdf.

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Thesis (M.S. in Mechanical Engineering and Mechanical Engineer) Naval Postgraduate School, June 1998.
Title from cover. Thesis advisor(s): Anthony J. Healey. "June 1998."--Cover. "NPS-ME-98-004"--Cover. Includes bibliographical references (p. 117-118). Also available online.
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Ellison, Aaron S. "Simulation of a radar detection model using the NPS platform foundation." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1996. http://handle.dtic.mil/100.2/ADA311143.

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Surovič, Marek. "Statická detekce malware nad LLVM IR." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2016. http://www.nusl.cz/ntk/nusl-255427.

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Tato práce se zabývá metodami pro behaviorální detekci malware, které využívají techniky formální analýzy a verifikace. Základem je odvozování stromových automatů z grafů závislostí systémových volání, které jsou získány pomocí statické analýzy LLVM IR. V rámci práce je implementován prototyp detektoru, který využívá překladačovou infrastrukturu LLVM. Pro experimentální ověření detektoru je použit překladač jazyka C/C++, který je schopen generovat mutace malware za pomoci obfuskujících transformací. Výsledky předběžných experimentů a případná budoucí rozšíření detektoru jsou diskutovány v závěru práce.
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Li, Qiongzhu. "Study of Single and Ensemble Machine Learning Models on Credit Data to Detect Underlying Non-performing Loans." Thesis, Uppsala universitet, Statistiska institutionen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-297080.

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In this paper, we try to compare the performance of two feature dimension reduction methods, the LASSO and PCA. Both simulation study and empirical study show that the LASSO is superior to PCA when selecting significant variables. We apply Logistics Regression (LR), Artificial Neural Network (ANN), Support Vector Machine (SVM), Decision Tree (DT) and their corresponding ensemble machines constructed by bagging and adaptive boosting (adaboost) in our study. Three experiments are conducted to explore the impact of class-unbalanced data set on all models. Empirical study indicates that when the percentage of performing loans exceeds 83.3%, the training models shall be carefully applied. When we have class-balanced data set, ensemble machines indeed have a better performance over single machines. The weaker the single machine, the more obvious the improvement we can observe.
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Books on the topic "NPD DETECTOR"

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Marino, Stephen A. Operation and calibration of the NPS Ultraviolet Imaging Spectrometer (NUVIS) in the detection of sulfur dioxide plumes. Monterey, Calif: Naval Postgraduate School, 1999.

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Simulation of a Radar Detection Model Using the NPS Platform Foundation. Storming Media, 1996.

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Operational and Calibration of the NPS Ultraviolet Imaging Spectrometer (NUVIS) in the Detection of Sulfur Dioxide Plumes. Storming Media, 1999.

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Book chapters on the topic "NPD DETECTOR"

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Krzysztoń, Mateusz, Marcin Lew, and Michał Marks. "NAD: Machine Learning Based Component for Unknown Attack Detection in Network Traffic." In Cybersecurity of Digital Service Chains, 83–102. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-04036-8_4.

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AbstractDetection of unknown attacks is challenging due to the lack of exemplary attack vectors. However, previously unknown attacks are a significant danger for systems due to a lack of tools for protecting systems against them, especially in fast-evolving Internet of Things (IoT) technology. The most widely used approach for malicious behaviour of the monitored system is detecting anomalies. The vicious behaviour might result from an attack (both known and unknown) or accidental breakdown. We present a Net Anomaly Detector (NAD) system that uses one-class classification Machine Learning techniques to detect anomalies in the network traffic. The highly modular architecture allows the system to be expanded with adapters for various types of networks. We propose and discuss multiple approaches for increasing detection quality and easing the component deployment in unknown networks by known attacks emulation, exhaustive feature extraction, hyperparameter tuning, detection threshold adaptation and ensemble models strategies. Furthermore, we present both centralized and decentralized deployment schemes and present preliminary results of experiments for the TCP/IP network traffic conducted on the CIC-IDS2017 dataset.
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Herrero, Álvaro, and Emilio Corchado. "Previous Work on NID." In Mobile Hybrid Intrusion Detection, 41–70. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-18299-0_3.

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Holland, Patrick T. "Capillary GC with Selective Detectors (ECD, NPD, FPD)." In Chemistry of Plant Protection, 67–112. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-662-03156-8_4.

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Kang, Yeon Gu, Hyun Jea Joo, and Phill Kyu Rhee. "Real Time Head Nod and Shake Detection Using HMMs." In Lecture Notes in Computer Science, 707–14. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/11893011_90.

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Rana, Kailash, and Dheeraj Joshi. "Open-Switch Fault Detection in NPC Voltage Source Inverter." In Studies in Infrastructure and Control, 203–11. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-8963-6_19.

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Jahagirdar, Padmashri, and Suneeta V. Budihal. "Framework to Detect NPK Deficiency in Maize Plants Using CNN." In Advances in Intelligent Systems and Computing, 366–76. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-6353-9_33.

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Mehdi, Itrat, Abdul Aziz Al Farsi, Bassim Al Bahrani, and Shadha S. Al-Raisi. "General Oncology Care in Oman." In Cancer in the Arab World, 175–93. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-7945-2_12.

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AbstractThe Sultanate of Oman is located on the Arabian Peninsula and is part of Western Asia. Oman has a relatively young population. The economy is based on oil, agriculture, fishing, and overseas trading. Oman spends around 3% of its GDP on health care. Omani nationals have free access to public healthcare. Due to increased incomes and changing lifestyles, the rate of Non-Communicable Diseases (NCD) including cancer is rising. This is slowly saturating the system and increasing health care costs. Cancer is now the third leading cause of mortality. The age-adjusted annual incidence of cancer ranges from 70 to 110 per 100,000 population. Oman has an operational national NCD action plan. This multi-sectoral plan was launched in 2018 and focuses on the government approach in addressing NCDs including cancer, highlighting the prevention and control strategies. There is an integrated cancer care service, cancer registry, and cancer control program; under the auspices of the Directorate general of Non-communicable diseases—Ministry of Health. Oman has envisioned an ambitious long-term health care plan called “Health care Vision 2050”, which includes the development and progression of cancer care services as well. This plan has an emphasis on development, patient empowerment, public awareness, health education, integration and accessibility of services, screening, and early detection, public–private partnership, indulgence for NGOs, research, and capacity building.
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Lalitha, R. V. Satya, Rayudu Srinivas, Ch V. Raghavendran, K. Kavitha, Pullela S. V. V. S. R. Kumar, and P. S. L. Sravanthi. "Real Time Nitrogen, Phosphorus, Potassium (NPK) Detection in Soil Using IoT." In Advanced Techniques for IoT Applications, 408–16. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-4435-1_39.

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Chen, Jen-Yang, Yueh-Hsing Ou, Tswey-Ying Hsu, Mei-Ying Liu, Teh-Shiou Huang, Lei-Ron Jan, Sheau-Wei Jang, Chun-Huey Chang, and Czau-Siung Yang. "Detection of EBV DNA in Nude Mouse Passaged Nasopharyngeal Carcinoma (NPC) Tissues." In Epstein-Barr Virus and Human Disease, 183–87. Totowa, NJ: Humana Press, 1987. http://dx.doi.org/10.1007/978-1-4612-4590-2_40.

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Zeng, Yi, and Guy de The. "Nasopharyngeal Carcinoma : Early Detection and IGA-Related Pre-NPC Condition.Achievements and Prospectives." In Epstein-Barr Virus and Associated Diseases, 151–63. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4613-2625-0_13.

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Conference papers on the topic "NPD DETECTOR"

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"PV-086 - EL RETO DE LAS NUEVAS DROGAS PSICOACTIVAS EN TRASTORNO MENTAL GRAVE." In 24 CONGRESO DE LA SOCIEDAD ESPAÑOLA DE PATOLOGÍA DUAL. SEPD, 2022. http://dx.doi.org/10.17579/abstractbooksepd2022.pv086.

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OBJETIVOS Explorar la información disponible hasta el momento sobre el consumo de Nuevas Drogas Psicoactivas (NDP) en personas con Trastorno Mental Grave (TMG), así como detectar los retos de cara a mejorar el conocimiento en este campo. MATERIAL Y MÉTODOS Se ha realizado una revisión de estudios científicos hasta 2022 sobre el tema a tratar en PubMed y MedLine, incluyendo estudios en inglés que indagasen sobre el uso de NDP en adultos con TMG. Palabras clave: “Novel/New Psychoactive Substances/NPS”, “Schizophrenia”, “bipolar disorder”, “Severe Mental Illness/SMI”. También se han consultado revisiones previas relevantes y referencias bibliográficas de algunos estudios. RESULTADOS Y CONCLUSIONES Se ha sugerido que el uso de NDP podría ser más común en personas con patología psiquiátrica que en sanos, y que los pacientes con patología dual presentan peor evolución clínica. Por ello, sería conveniente conocer mejor la repercusión de NDP en TMG. Algunos estudios sostienen que el empleo de NDP en TMG desembocó en alteración conductual más grave y síntomas psicóticos de características clínicas diferentes a las exacerbaciones previas, aunque se requiere mayor evidencia. Algunas limitaciones que impiden un mayor conocimiento en este campo son: - escasos estudios sobre el tema, siendo la mayoría series de casos o casos únicos - constante incremento de NDP (se vigilan más de 830 NDP) - las NDP no se detectan en los controles rutinarios de Urgencias, quedando supeditados a la anamnesis y exploración física, pudiendo derivar en una subestimación del uso de NDP y en un manejo inadecuado. Es esencial que los psiquiatras se mantengan actualizados en la sospecha y manejo del consumo de NDP. Son necesarios más estudios para establecer la interacción entre NDP y TMG para un mejor abordaje del paciente. Un mejor registro del uso de drogas y herramientas más objetivas para detectar NDP ayudarían en futuras investigaciones.
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Zvorykina, Anastasiia, Georgij Sharayevskiy, Nataliya Fialko, and Nina Sharayevskaya. "Methodology for Verification of the Heat Transfer Crisis in the Nuclear Fuel Assemblies." In 2013 21st International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icone21-15424.

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The present-day stage of nuclear-power engineering development raises sharply a number of complicated questions regarding the guarantee of safety operation of nuclear power-generating units of operating and designed Nuclear Power Plant (NPP). The most important of these unsolved technological problems were considered in [1] on the base of analysis of ways of operation reliability improvement for Nuclear Power Installations (NPI) with WWER and RBMK reactors. In connection with the priorities formulated in [1], in papers [2–6] the main aspects of approaches available for solution of most complex problem are considered: the development of methods of early identification of initial phases of emergency operation regimes in such nuclear power-generating units which are critically important for NPI trouble-free operation. It is necessary to stress, that reliable identification of the anomalies mentioned, especially of thermal-hydraulic nature ones in core region of nuclear reactor, must be provided under conditions when such operating troubles can not yet be detected by the issued supervisory instruments of NPI. Taking into account the requirement to prospective diagnostic provision of NPP equipment, in papers [2–5] are underlined that at present time the development of effective methods of anomalies identification in NPI equipment and development of mathematical software support on base of these methods for computer-aided diagnostic systems on base of AI conceptions in structure of hardware of operator support tools of new generation NPP are considered as the main condition which determine the development of diagnostic means with mentioned functional possibilities.
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Cannarile, Francesco, Stefano Montoli, Giuseppe Giliberto, Mauro Suardi, Benedetta Di Bari, Gaetano Formato, Daniele Farina, et al. "A Change Point Detection Approach for Intelligent Real-Time Identification of Lost Circulation Events During Drilling Operations." In Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/207643-ms.

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Abstract Lost circulation is a challenging aspect during drilling operations as uncontrolled flow of wellbore fluids into formation can expose rig personnel and environment to risks. Further, the time required to regain the circulation of drilling fluid typically results in unplanned Non-Productive Time (NPT) causing undesired amplified drilling cost. Thus, it is of primary importance to support drilling supervisors with accurate and effective detection tools for safe and economic drilling operations. In this framework, a novel lost circulation intelligent detection system is proposed which relies on the simultaneous identification of decreasing trends in the paddle mud flow-out and standpipe pressure signals, at constant mud flow-in rate. First, mud flow-out and standpipe pressure signals underlie cubic-spline-based smoothing step to remove background noise caused by the measurement instrument and the intrinsic variability of the drilling environment. To identify structural changes in the considered signals, a nonparametric kernel-based change point detection algorithm is employed. Finally, an alarm is raised if flow-out and standpipe pressure decreasing trends have been detected and their negative variations are below prefixed threshold values. The proposed intelligent lost circulation detection system has been verified with respect to historical field data recorded from several Eni wells located in different countries. Results show that the proposed system satisfactorily and reliably detects both partial and total lost circulation events. Further, its integration with already existing Eni NPT prediction models has led to a significant improvement in terms of events correctly triggered.
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Kolodziej, Joanna, Mateusz Krzyszton, and Pawel Szynkiewicz. "Anomaly Detection In TCP/IP Networks." In 37th ECMS International Conference on Modelling and Simulation. ECMS, 2023. http://dx.doi.org/10.7148/2023-0542.

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Intrusion Detection Systems (IDS) should be capable of quickly detecting attacks and network traffic anomalies to reduce the damage to the network components. They may efficiently detect threats based on prior knowledge of attack characteristics and the potential threat impact ('known attacks'). However, IDS cannot recognize threats, and attacks ('unknown attacks') usually occur when using brand-new technologies for system damage. This paper presents two security services -- Net Anomaly Detector (NAD) and a signature-based PGA Filter for detecting attacks and anomalies in TCP/IP networks. Both services are modules of the cloud-based GUARD platform developed in the H2020 GUARD project. Such a platform was the main component of the simulation environment in the work presented in this paper. The provided experiments show that both modules achieved satisfactory results in detecting an unknown type of DoS attacks and signatures of DDoS attacks.
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Zhai, Ya-Hong, Ping Li, Wei Li, Guo-Jun Zhang, Yu-Xiang Luo, Bin Hu, and Xue Fan. "Total-dose hardened of a bipolar NPN differential pair." In International Symposium on Photoelectronic Detection and Imaging 2011, edited by John C. Zarnecki, Carl A. Nardell, Rong Shu, Jianfeng Yang, and Yunhua Zhang. SPIE, 2011. http://dx.doi.org/10.1117/12.900652.

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Yang, Tan Ping, and Vijanth Sagayan Asirvadam. "Optimizing detector placement and mapping using imaging techniques." In 2011 National Postgraduate Conference (NPC). IEEE, 2011. http://dx.doi.org/10.1109/natpc.2011.6136387.

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Ma, Jianping, and Jin Jiang. "Fault Detection and Identification in NPP Instruments Using Kernel Principal Component Analysis." In 18th International Conference on Nuclear Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/icone18-29777.

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In this paper, kernel principal component analysis (KPCA) is studied for fault detection and identification in the instruments of nuclear power plants. We propose to use mean values of the sensor reconstruction errors of a KPCA model for fault isolation and identification. They provide useful information about the directions and magnitudes of detected faults, which are usually not available from other fault isolation techniques. The performance of the method is demonstrated by applications to real NPP measurements.
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Fan, Hongkang, Shanhong Jiang, XianHai Zhou, Guo Wang, Haobo Zhou, and Hongning Zhang. "A Comprehensive Model for Gas Influx Detection and Control While Managed Pressure Drilling and Its Application." In IADC/SPE Asia Pacific Drilling Technology Conference. SPE, 2021. http://dx.doi.org/10.2118/201001-ms.

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Abstract The equipment commonly used in managed pressure drilling (MPD) allows alternative responses to kicks that do not need to stop the pump or shut in the well. The pivotal issue of kick control for MPD is the early gas influx detection and the optimal initial response when the kick was detected during drilling. The careful research on gas influx detection and the corresponding control method is very important. Firstly, the valve opening, bottom hole and well head pressure variation characteristics were analyzed based on the real-time measured data, and then the valve opening and pressure signature of gas influx for different MPD modes (CBHP, CWHP, MFC) was obtained based on the theoretical and model analysis, in which the pressure variation caused by the tripping, ROP and flow rate variation were taken into account, through which the gas kick can accurately detected as soon as quickly. Secondly, the influence factors for initial response selection of kick control was analyzed, and then the comprehensive optimization schedule of response for kick control was established, in which several factors were took into account, such as formation characteristics, drilling conditions, influx intensity and so on, through which the best mode for kick control can be obtained easily. Moreover, integrated software that combined kick detection and gas kick control simulation was developed based on which the best pressure control procedure and kick initial response can be obtained easily. The gas influx detection and control technique has been applied in Fuling shale gas field of SINOPEC, which is the first large-scale commercial development shale gas field of China. The results show that we can make precisely gas detection based on the new early gas influx detection method and the kick can also be control very well based on the optimization method. Based on the proposed method for kick detection and control, the NPT have been reduced more than 60%. This study will presented a novel gas kick detection theoretical model for all common MPD modes, and the gas influx control optimal procedure. Through the field application in shale gas drilling, the results show that the NPT has been reduced obviously, and the optimal kick control was designed has successfully prevented the serious kick and reduced the drilling cost.
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Reis, Vinícius, and Gustavo Vieira. "Eleição de Líder com Qualidade de Serviço para o Modelo Falha-e-Recuperação." In XXXVI Simpósio Brasileiro de Redes de Computadores e Sistemas Distribuídos. Sociedade Brasileira de Computação - SBC, 2021. http://dx.doi.org/10.5753/sbrc_estendido.2018.14176.

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Um dos objetivos de um sistema distribuído é prover poder computacional e persistência de dados mesmo na presença de falhas de um subconjunto de enlaces e processos. Para determinar quais são os processos defeituosos deste sistema e abstrair o conceito de tempo, estes sistemas utilizam os serviços de um detector de falhas não confiável, encapsulado em um algoritmo de eleição de líder. Embora a literatura sobre a qualidade de serviço (QoS) oferecida por detectores de falhas seja abundante, ela é escassa quando se trata da QoS oferecida por algoritmos de eleição de líder. Nesta dissertação propomos um algoritmo de eleição de líder para o modelo falha-e-recuperação denominado NFD-L, que segue as especificações de QoS originalmente apresentadas em [Chen et al. 2002]. Utilizamos NFD-L em uma aplicação para replicação, como mecanismo de eleição de coordenador para Paxos e apresentamos uma análise da QoS observada, comparando o seu comportamento com um algoritmo de eleição de líder que não foi projetado explicitamente para prover garantias de QoS.
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Ali, Syeda Qurat-ul-Ain, and Varun Jeoti. "DWPT based sleep apnea detection." In 2011 National Postgraduate Conference (NPC). IEEE, 2011. http://dx.doi.org/10.1109/natpc.2011.6136432.

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Reports on the topic "NPD DETECTOR"

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Palasek, R. Network intrusion detector: NID user`s guide V 1.0. Office of Scientific and Technical Information (OSTI), April 1994. http://dx.doi.org/10.2172/10176285.

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Admas, C., and et al. LAr1-ND: Testing Neutrino Anomalies with Multiple LAr TPC Detectors at Fermilab. Office of Scientific and Technical Information (OSTI), December 2013. http://dx.doi.org/10.2172/1156551.

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Haines and Rosenfeld. L52125 Physical Performance and Inspection Objectives to Inspect Currently Non Piggable Pipelines. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), January 2004. http://dx.doi.org/10.55274/r0011137.

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A significant portion of the pipeline infrastructure cannot be assessed for integrity using in-line inspection. There may also be reasons why some segments cannot be readily assessed by hydrostatic testing or by direct assessment. New standards and regulations for integrity management provide for using other technology that can be demonstrated to be as effective in assessing for the presence of integrity threats as the standard techniques. The first part of the report discusses a survey of PRCI member pipeline operating companies investigating the reasons why their systems are not piggable. The results are intended to be an aid to determining the direction of future PRCI research and development efforts. The results revealed that 62% of the pipe surveyed is presently piggable, and those members answering the survey plan to make another 21% of the system piggable. The survey further indicated that members plan to use direct assessment as the primary choice for inspecting nonpiggable segments. Consequently, the survey suggests that the primary goal of the Committee in addressing nonpiggable lines should be to validate direct assessment, followed by developing new above ground direct assessment and metal loss detection tools. The second part of the report discusses an analysis to establish suitable detection criteria for alternative assessment methods. Criteria for metal loss due to corrosion were established for 2 NPS to 24 NPS pipe of Grades B, X42, and X52 in all standard class locations so as to assure the same margin of safety afforded by the minimum hydrostatic test required per class. Criteria were also proposed for stress-corrosion cracking, selective corrosion in ERW seams, and mechanical damage.
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Roberts, Samuel, Elizabeth Tymkiw, Zachary Ladin, and Greg Shriver. Status and trends of landbird populations in the Northern Colorado Plateau Network: 2022 field season. Edited by Alice Wondrak Biel. National Park Service, June 2023. http://dx.doi.org/10.36967/2299435.

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In 2022, the University of Delaware, in cooperation with the National Park Service (NPS), completed the seventeenth year of a habitat-based landbird monitoring program in park units of the Northern Colorado Plateau Network (NCPN). This program is designed to provide rigorous population trend data for most diurnal, regularly occurring breeding landbird spe-cies throughout the network. This population information is useful for land managers and supports the National Park Service’s goal of long-term monitoring of biological indicators for network parks. In 2022, university biologists surveyed all 45 survey locations within 11 NPS units. Fifteen transects were located in each of the three habitats of interest: low-elevation riparian, pin-yon-juniper, and sagebrush shrubland. Each location was surveyed once. In addition to the habitat-based surveys, four point counts and an area search were conducted at Pipe Spring National Monument using a modified monitoring design. Over 17 years of data collection, 15,777 point-count surveys have been conducted in 11 NCPN units, detecting 179 unique species. During the 2022 field season, 638 point-count surveys were conducted, detecting 117 unique species. A total of 6,245 individual birds of 117 unique species were recorded. One new species was detected for this monitoring pro-gram: a Lewis’s woodpecker (Melanerpes lewis) in Black Canyon of the Gunnison National Park. In addition, the following birds were detected in the following parks for the first time in this monitoring program: lazuli bunting (Passerina amoena), Black Canyon of the Gun-nison National Park; summer tanager (Piranga rubra), Arches National Park; MacGillivray’s warbler (Geothlypis tolmiei), Bryce Canyon National Park; red-naped sapsucker (Sphyrapicus nuchalis), Curecanti National Recreation Area, and Lincoln’s sparrow (Melospiza lincolnii), Zion National Park.
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DeSaix, Matthew. Bird community monitoring at New River Gorge National River, Gauley River National Recreation Area, and Bluestone National Scenic River, 1997 - 2018. National Park Service, January 2022. http://dx.doi.org/10.36967/nrr-2289846.

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Birds are prominent features of National Park Service lands and are effective indicators for monitoring ecosystem health. Assessing the temporal change of avian species abundance depends on long-term monitoring of bird communities and trends, however long-term monitoring programs are generally uncommon. In this report, we summarize 22 years (1997-2018) of point count data across five sites on West Virginia National Park Service lands (three in New River Gorge National River, one in Gauley River National Recreation Area, and one in Bluestone National Scenic River) and compare these results to our analysis of Breeding Bird Survey data for the same time period across all of West Virginia. The objectives of this analysis are two-fold: 1) describe the biotic integrity of the National Park Service lands in West Virginia and 2) Quantify trends in guilds and species abundance. During the 20-year period of this survey, 85 breeding resident species were detected. The West Virginia National Park Service lands are home to stable populations of Wood Thrush and Yellow-billed Cuckoo, both species of continental concern by Partners in Flight. Seven species have declined precipitously on NPS lands during this time period. Three of these species are also experiencing declines across the rest of West Virginia (Blue-gray Gnatcatcher, Carolina Chickadee, Kentucky Warbler), but the other 4 species are stable across West Virginia (Acadian Flycatcher, Black-throated Green Warbler, Northern Parula, Swainson’s Warbler). Four species that are declining across West Virginia (Great Crested Flycatcher, Indigo Bunting, Red-eyed Vireo, and Worm-eating Warbler) are stable on southern West Virginia NPS lands. Additionally, the upper-canopy foraging guild of species has decreased significantly on NPS lands in southern West Virginia. An analysis of community biotic integrity revealed that the southern West Virginia NPS lands have been stable at a rating of high biotic integrity every year for the duration of this survey. Future research should delve into the underlying factors that may be driving the trends in abundance at different scales.
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Baader, Franz, Stefan Borgwardt, and Barbara Morawska. SAT Encoding of Unification in ELHR+ w.r.t. Cycle-Restricted Ontologies. Technische Universität Dresden, 2012. http://dx.doi.org/10.25368/2022.186.

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Unification in Description Logics has been proposed as an inference service that can, for example, be used to detect redundancies in ontologies. For the Description Logic EL, which is used to define several large biomedical ontologies, unification is NP-complete. An NP unification algorithm for EL based on a translation into propositional satisfiability (SAT) has recently been presented. In this report, we extend this SAT encoding in two directions: on the one hand, we add general concept inclusion axioms, and on the other hand, we add role hierarchies (H) and transitive roles (R+). For the translation to be complete, however, the ontology needs to satisfy a certain cycle restriction. The SAT translation depends on a new rewriting-based characterization of subsumption w.r.t. ELHR+-ontologies.
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Baader, Franz, Stefan Borgwardt, and Barbara Morawska. A Goal-Oriented Algorithm for Unification in ELHR+ w.r.t. Cycle-Restricted Ontologies. Technische Universität Dresden, 2012. http://dx.doi.org/10.25368/2022.189.

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Unification in Description Logics (DLs) has been proposed as an inference service that can, for example, be used to detect redundancies in ontologies. For the DL EL, which is used to define several large biomedical ontologies, unification is NP-complete. A goal-oriented NP unification algorithm for EL that uses nondeterministic rules to transform a given unification problem into solved form has recently been presented. In this report, we extend this goal-oriented algorithm in two directions: on the one hand, we add general concept inclusion axioms (GCIs), and on the other hand, we add role hierarchies (H) and transitive roles (R+). For the algorithm to be complete, however, the ontology consisting of the GCIs and role axioms needs to satisfy a certain cycle restriction.
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Baader, Franz, Stefan Borgwardt, and Barbara Morawska. Dismatching and Local Disunification in EL. Technische Universität Dresden, 2014. http://dx.doi.org/10.25368/2022.210.

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Unification in Description Logics has been introduced as a means to detect redundancies in ontologies. We try to extend the known decidability results for unification in the Description Logic EL to disunification since negative constraints on unifiers can be used to avoid unwanted unifiers. While decidability of the solvability of general EL-disunification problems remains an open problem, we obtain NP-completeness results for two interesting special cases: dismatching problems, where one side of each negative constraint must be ground, and local solvability of disunification problems, where we restrict the attention to solutions that are built from so-called atoms occurring in the input problem. More precisely, we first show that dismatching can be reduced to local disunification, and then provide two complementary NP-algorithms for finding local solutions of (general) disunification problems.
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Baader, Franz, and Barbara Morawska. SAT Encoding of Unification in EL. Technische Universität Dresden, 2010. http://dx.doi.org/10.25368/2022.177.

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The Description Logic EL is an inexpressive knowledge representation language, which nevertheless has recently drawn considerable attention in the knowledge representation and the ontology community since, on the one hand, important inference problems such as the subsumption problem are polynomial. On the other hand, EL is used to define large biomedical ontologies. Unification in Description Logics has been proposed as a novel inference service that can, for example, be used to detect redundancies in ontologies. In a recent paper, we have shown that unification in EL is NP-complete, and thus of a complexity that is considerably lower than in other Description Logics of comparably restricted expressive power. In this paper, we introduce a new NP-algorithm for solving unification problem in EL, which is based on a reduction to satisfiability in propositional logic (SAT). The advantage of this new algorithm is, on the one hand, that it allows us to employ highly optimized state of the art SAT solverswhen implementing an EL-unification algorithm. On the other hand, this reduction provides us with a proof of the fact that EL-unification is in NP that is much simpler than the one given in our previous paper on EL-unification.
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Baader, Franz, Oliver Fernández Gil, and Barbara Morawska. Hybrid Unification in the Description Logic EL. Technische Universität Dresden, 2013. http://dx.doi.org/10.25368/2022.197.

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Unification in Description Logics (DLs) has been proposed as an inference service that can, for example, be used to detect redundancies in ontologies. For the DL EL, which is used to define several large biomedical ontologies, unification is NP-complete. However, the unification algorithms for EL developed until recently could not deal with ontologies containing general concept inclusions (GCIs). In a series of recent papers we have made some progress towards addressing this problem, but the ontologies the developed unification algorithms can deal with need to satisfy a certain cycle restriction. In the present paper, we follow a different approach. Instead of restricting the input ontologies, we generalize the notion of unifiers to so-called hybrid unifiers. Whereas classical unifiers can be viewed as acyclic TBoxes, hybrid unifiers are cyclic TBoxes, which are interpreted together with the ontology of the input using a hybrid semantics that combines fixpoint and descriptive semantics. We show that hybrid unification in EL is NP-complete and introduce a goal-oriented algorithm for computing hybrid unifiers.
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