Academic literature on the topic 'Qh 244'
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Journal articles on the topic "Qh 244"
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Hirota-Mamoto, Rie, Ryoko Nagai, Shinjiro Tachibana, Masaaki Yasuda, Akio Tani, Kazuhide Kimbara, and Fusako Kawai. "Cloning and expression of the gene for periplasmic poly(vinyl alcohol) dehydrogenase from Sphingomonas sp. strain 113P3, a novel-type quinohaemoprotein alcohol dehydrogenase." Microbiology 152, no. 7 (July 1, 2006): 1941–49. http://dx.doi.org/10.1099/mic.0.28848-0.
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A gene for periplasmic poly(vinyl alcohol) (PVA) dehydrogenase (PVADH) was cloned, based on the N-terminal amino acid sequence of the purified PVADH from Sphingomonas sp. 113P3 and the sequence of the gene for PVADH (pvaA, GenBank accession no. AB190288). The recombinant PVADH tagged with hexahistidine was expressed in Escherichia coli and purified to homogeneity. The recombinant enzyme had the same characteristics as the purified enzyme from Sphingomonas sp. strain 113P. In addition to PVA, the recombinant PVADH could oxidize glycols such as polypropylene glycols and 1,3-butane/cyclohexanediol and 2,4-pentanediol, but neither primary nor secondary alcohols. The amino acid sequence of the recombinant PVADH showed similarity with those of PVADH from Pseudomonas sp. strain VM15C, putative PVADHs from Azoarcus sp. EbN1, and Xanthomonas species (54–25 % identity), and the quinohaemoprotein alcohol dehydrogenases (QH-ADHs) from Comamonas testosteroni, Ralstonia eutropha and Pseudomonas putida (25–29 % identity). PVADHs from strains 113P3 and VM15C have a conserved superbarrel domain (SD), probable PQQ-binding amino acids in the SD and a haem-binding domain (HBD) (they should be designated QH-PVADHs), but the positions of the amino acid sequences for the HBD and SD are the reverse of those of QH-ADHs. A protein structure of QH-PVADHs is proposed. Results of dot-blot hybridization and RT-PCR indicated that the three genes encoding oxidized PVA hydrolase, PVADH and cytochrome c are expressed constitutively and form an operon.
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Gawlik, Anna, George Lee, Michael D. Feldman, Guangjing Zhu, Robert W. Veltri, and Anant Madabhushi. "Computer extracted nuclear features from tumor and benign regions of Feulgen and H&E images to help predict recurrence in prostate cancer patients following radical prostatectomy." Journal of Clinical Oncology 35, no. 15_suppl (May 20, 2017): e16556-e16556. http://dx.doi.org/10.1200/jco.2017.35.15_suppl.e16556.
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e16556 Background: Following radical prostatectomy, around 30% of prostate cancer (PCa) patients experience biochemical recurrence (BCR). H&E highlights nuclear morphology and Feulgen reflects nuclear DNA content, a feature linked to PCa presence and aggressiveness. In this work we sought to explore whether computer extracted measurements of tumor morphology and tumor adjacent benign regions on H&E and Feulgen tissue images could predict BCR. Methods: We used 108 patients (59 BCR and 49 non-recurrence (NR)) and each patient had 242 QH features calculated from both the tumor and benign region of stained TMA core images. Feature selection was performed on a training set (30 BCR, 24 NR) to select the 10 most discriminating tumor and tumor adjacent benign features of each stain. A random forest classifier was trained with features so identified and validated on a test set (29 BCR, 25 NR) to predict BCR. Predictions were displayed using Kaplan-Meier analysis and area under the ROC curve (AUC). Results: The most discriminating feature from the tumor regions of the H&E stain was Fourier descriptors of nuclear shape and from the Feulgen stain was texture intensity while from the benign regions it was invariant moments of nuclear shape and texture contrast energy. Combining the significant features from tumor and tumor adjacent benign regions from H&E and Feulgen resulted in the highest accuracy and a statistically significant difference (p < 0.05) via a log-rank test (Table 1). Gleason score did not show statistically significant differences and had the lowest AUC. Conclusions: Combining nuclear morphology and DNA related features of the tumor and tumor adjacent benign regions enabled accurate prediction of BCR. With additional multi-site validation, the combined H&E + Feulgen classifier could allow better risk stratification and post-surgical patient management. [Table: see text]
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Röhr, Susanne, Alexander Pabst, Steffi G. Riedel-Heller, Frank Jessen, Yuda Turana, Yvonne S. Handajani, Carol Brayne, et al. "Estimating prevalence of subjective cognitive decline in and across international cohort studies of aging: a COSMIC study." Alzheimer's Research & Therapy 12, no. 1 (December 2020). http://dx.doi.org/10.1186/s13195-020-00734-y.
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Abstract Background Subjective cognitive decline (SCD) is recognized as a risk stage for Alzheimer’s disease (AD) and other dementias, but its prevalence is not well known. We aimed to use uniform criteria to better estimate SCD prevalence across international cohorts. Methods We combined individual participant data for 16 cohorts from 15 countries (members of the COSMIC consortium) and used qualitative and quantitative (Item Response Theory/IRT) harmonization techniques to estimate SCD prevalence. Results The sample comprised 39,387 cognitively unimpaired individuals above age 60. The prevalence of SCD across studies was around one quarter with both qualitative harmonization/QH (23.8%, 95%CI = 23.3–24.4%) and IRT (25.6%, 95%CI = 25.1–26.1%); however, prevalence estimates varied largely between studies (QH 6.1%, 95%CI = 5.1–7.0%, to 52.7%, 95%CI = 47.4–58.0%; IRT: 7.8%, 95%CI = 6.8–8.9%, to 52.7%, 95%CI = 47.4–58.0%). Across studies, SCD prevalence was higher in men than women, in lower levels of education, in Asian and Black African people compared to White people, in lower- and middle-income countries compared to high-income countries, and in studies conducted in later decades. Conclusions SCD is frequent in old age. Having a quarter of older individuals with SCD warrants further investigation of its significance, as a risk stage for AD and other dementias, and of ways to help individuals with SCD who seek medical advice. Moreover, a standardized instrument to measure SCD is needed to overcome the measurement variability currently dominant in the field.
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Hien, Nguyen Dinh. "KẾT QUẢ KHẢO SÁT BƯỚC ĐẦU VỀ TÌNH HÌNH VIẾT SAI, VIẾT NHẦM CHỮ HÁN CỦA SINH VIÊN VIỆT NAM." VNU Journal of Foreign Studies 33, no. 1 (January 24, 2017). http://dx.doi.org/10.25073/2525-2445/vnufs.4124.
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Chữ Hán là một trong những khó khăn lớn nhất của sinh viên Việt Nam khi học tiếng Hán. Hiện tượng viết sai, viết nhầm diễn ra rất phổ biến, song những thành tựu nghiên cứu về lĩnh vực này còn tương đối hạn chế. Bài viết tiến hành khảo sát những chữ Hán viết sai, viết nhầm của sinh viên Việt Nam dựa trên việc phân tích ngữ liệu 150 bài thi tốt nghiệp môn viết của sinh viên khóa QH 2011, Khoa Ngôn ngữ và Văn hóa Trung Quốc, Trường Đại học Ngoại ngữ, Đại học Quốc gia Hà Nội (ĐHQGHN). Tiếp đó, bài viết đi sâu vào phân loại các chữ viết sai, viết nhầm, trên cơ sở đó đưa ra những kiến nghị đối với việc dạy và học chữ Hán cho sinh viên chuyên ngành tiếng Trung Quốc của Việt Nam.
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Aad, G., B. Abbott, K. Abeling, N. J. Abicht, S. H. Abidi, A. Aboulhorma, H. Abramowicz, et al. "Search for flavour-changing neutral tqH interactions with H → γγ in pp collisions at $$ \sqrt{s} $$ = 13 TeV using the ATLAS detector." Journal of High Energy Physics 2023, no. 12 (December 28, 2023). http://dx.doi.org/10.1007/jhep12(2023)195.
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Abstract A search for flavour-changing neutral interactions involving the top quark, the Higgs boson and an up-type quark q (q = c, u) is presented. The proton-proton collision data set used, with an integrated luminosity of 139 fb−1, was collected at $$ \sqrt{s} $$ s = 13 TeV by the ATLAS experiment at the Large Hadron Collider. Both the decay process t → qH in $$ t\overline{t} $$ t t ¯ production and the production process pp → tH, with the Higgs boson decaying into two photons, are investigated. No significant excess is observed and upper limits are set on the t → cH and the t → uH branching ratios of 4.3 × 10−4 and 3.8 × 10−4, respectively, at the 95% confidence level, while the expected limits in the absence of signal are 4.7 × 10−4 and 3.9 × 10−4. Combining this search with ATLAS searches in the H → τ+τ− and H → $$ b\overline{b} $$ b b ¯ final states yields observed (expected) upper limits on the t → cH branching ratio of 5.8 × 10−4 (3.0 × 10−4) at the 95% confidence level. The corresponding observed (expected) upper limit on the t → uH branching ratio is 4.0 × 10−4 (2.4 × 10−4).
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Ye, Shenglan, Yang Zhang, and Xiaoxiao Shu. "Effects of microbial-phytoremediation on plant diversity and soil physico-chemical properties in northern shaanxi coal mining area, china." Bangladesh Journal of Botany, August 31, 2023, 495–502. http://dx.doi.org/10.3329/bjb.v52i2.68290.
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Effects of different microorganisms-plant combination on the diversity of plant and soil physics in the mining area were studied. Results showed that the number of species, total number and coverage of Soil Remediation + Vetiver + Sea-buckthorn (AH) treatment were 13, 298 and 89.8%, respectively, which were significantly higher than other treatments. Soil water content in different treatments was the highest at 20 cm. The pH value of the different treatments decreased significantly, and the pH value of AH was the lowest (7.14). The total nitrogen (TN) content of GH and GS were the highest, which were 0.54 and 0.51 g/kg, respectively. The contents of phosphorus (P) and available potassium (K) were the highest in AX treatment, reaching 57.1 and 194 mg/kg. Treatment with different inoculants significantly increased soil enzyme activity. The urease activity of GH was the highest, which was 0.872 mg/g. The sucrase activity and catalase content of AH and AX were the highest, which were 8.99, 8.53 mg/g and 2.145 ml/g, 1.872 ml/g, respectively. The phosphatase activities of QH and AH treatments were the highest at 234 and 229 mg/g, which were 6 times and 5.9 times than that of CK. Comprehensive analysis showed that microbial inoculum + mixed seeding mode can effectively improve soil fertility and enzyme activity, and the effect of AH was the best. Bangladesh J. Bot. 52(2): 495-502, 2023 (June) Special
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Ye, Shenglan, Yang Zhang, and Xiaoxiao Shu. "Effects of microbial-phytoremediation on plant diversity and soil physico-chemical properties in northern shaanxi coal mining area, china." Bangladesh Journal of Botany, August 31, 2023, 495–502. http://dx.doi.org/10.3329/bjb.v52i20.68290.
Full textAbstract:
Effects of different microorganisms-plant combination on the diversity of plant and soil physics in the mining area were studied. Results showed that the number of species, total number and coverage of Soil Remediation + Vetiver + Sea-buckthorn (AH) treatment were 13, 298 and 89.8%, respectively, which were significantly higher than other treatments. Soil water content in different treatments was the highest at 20 cm. The pH value of the different treatments decreased significantly, and the pH value of AH was the lowest (7.14). The total nitrogen (TN) content of GH and GS were the highest, which were 0.54 and 0.51 g/kg, respectively. The contents of phosphorus (P) and available potassium (K) were the highest in AX treatment, reaching 57.1 and 194 mg/kg. Treatment with different inoculants significantly increased soil enzyme activity. The urease activity of GH was the highest, which was 0.872 mg/g. The sucrase activity and catalase content of AH and AX were the highest, which were 8.99, 8.53 mg/g and 2.145 ml/g, 1.872 ml/g, respectively. The phosphatase activities of QH and AH treatments were the highest at 234 and 229 mg/g, which were 6 times and 5.9 times than that of CK. Comprehensive analysis showed that microbial inoculum + mixed seeding mode can effectively improve soil fertility and enzyme activity, and the effect of AH was the best. Bangladesh J. Bot. 52(2): 495-502, 2023 (June) Special
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Agyemang, Victor Ofori. "Geophysical investigation of groundwater potential and aquifer protective capability in selected communities within Cape Coast municipality, Ghana." Applied Water Science 12, no. 2 (January 28, 2022). http://dx.doi.org/10.1007/s13201-021-01558-3.
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AbstractApplication of VES geophysical technique to investigate the groundwater potential and the aquifer protective capability has been carried at Cape Coast Municipality, Ghana. The geology of Cape Coast is mainly made of the Secondian formation and the Eburnean Plutonic Suite. Twenty (20) VES points were selected after the profiling, and Schlumberger array was applied for the conduction of the VES. The PASI Resistivity Terrameter was used, and the maximum current electrode spacing (AB/2) was 100 m. Partial curve matching technique and computer iteration technique were applied in the interpretation data using WINRESIST software. The thematic maps of the parameters were generated to display their spatial variations using Surfer Golden software by the application of appropriate variograms depending on their range of values. The study revealed the presence of three to six layers curve types which include HKH (45%), QH (20%), HA (10%), KH (5%), QHKH (5%), A (5%), AKH (5%) and KHKH (5%) in the study area. The layers include topsoil (31.00–9135.00 Ω m), weathered layer (2.35–60,801.00 Ω m), fractured basement (4.39–32,431.00 Ω m), and fresh basement (59.40–22,521.00 Ω m). About 70% of the resistivities are less than 600 Ω m indicating the possibility of a fractured formation with high potential groundwater storage. The other 30% recorded high bedrock resistivities values of possible massive crystalline granitic rock with a limited fracture. Reflection coefficient and longitudinal conductance were calculated using appropriate equations and parameters. The values of the reflection coefficient ranged from 0.215606 to 0.997049. The study revealed that 20% of the total VES points have high groundwater potential, 65% showed medium potential, 5% showed low potential, while 10% showed very low potential. The study revealed poor (20%), moderate (35%), good (30%), and very good (15%) protective capacity ratings in the area. The technique has been effective in revealing the groundwater potential and the aquifer protective capability of the area. The aquiferous zone of the Secondian formation falls within the range of 17–43 m of depth with a borehole yield of 210–240 l/m. The successful borehole in the granitic rocks shows a low yield of 10 l/m with a water-saturated zone within 20–48 m of depth.
Dissertations / Theses on the topic "Qh 244"
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Rusch, Thomas, Patrick Mair, and Reinhold Hatzinger. "Psychometrics With R: A Review Of CRAN Packages For Item Response Theory." WU Vienna University of Economics and Business, 2013. http://epub.wu.ac.at/4010/1/resrepIRThandbook.pdf.
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In this paper we review the current state of R packages for Item Response Theory (IRT).
We group the available packages based on their purpose and provide an overview of each
package's main functionality. Each of the packages we describe has a peer-reviewed publication
associated with it. We also provide a tutorial analysis of data from the 1990
Workplace Industrial Relation Survey to show how the breadth and
exibility of IRT
packages in R can be leveraged to conduct even challenging item analyses with versatility
and ease. These items relate to the type of consultations that are carried out in a firm
when major changes are implemented. We first use unidimensional IRT models just to
discover that they fit do not fit well. We then use nonparametric IRT to explore the
possible causes for the scaling problem. Based on the results from the exploration, we
finally use a two-dimensional model on a subset of the original items to achieve a good
fit with a sensible interpretation, namely that there are two types of consultations a firm
may engage in: consultations with workers/representatives from the firm and with official
union representatives. The different items relate mostly to one of these dimensions and
firms can be scaled well along these two dimensions.Series: Discussion Paper Series / Center for Empirical Research Methods
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Zeileis, Achim, and Christian Kleiber. "Approximate replication of high-breakdown robust regression techniques." Department of Statistics and Mathematics, WU Vienna University of Economics and Business, 2008. http://epub.wu.ac.at/422/1/document.pdf.
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This paper demonstrates that even regression results obtained by techniques close to the standard ordinary least squares (OLS) method can be difficult to replicate if a stochastic model fitting algorithm is employed.Series: Research Report Series / Department of Statistics and Mathematics
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Zeileis, Achim, Ajay Shah, and Ila Patnaik. "Exchange Rate Regime Analysis Using Structural Change Methods." Department of Statistics and Mathematics, WU Vienna University of Economics and Business, 2007. http://epub.wu.ac.at/386/1/document.pdf.
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Regression models for de facto currency regime classification are complemented by inferential techniques for tracking the stability of exchange rate regimes. Several structural change methods are adapted to these regressions: tools for assessing the stability of exchange rate regressions in historical data (testing), in incoming data (monitoring) and for determining the breakpoints of shifts in the exchange rate regime (dating). The tools are illustrated by investigating the Chinese exchange rate regime after China gave up on a fixed exchange rate to the US dollar in 2005 and to track the evolution of the Indian exchange rate regime since 1993.Series: Research Report Series / Department of Statistics and Mathematics
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Zeileis, Achim, Christian Kleiber, and Simon Jackman. "Regression Models for Count Data in R." Department of Statistics and Mathematics, WU Vienna University of Economics and Business, 2007. http://epub.wu.ac.at/1168/1/document.pdf.
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The classical Poisson, geometric and negative binomial regression models for count data belong to the family of generalized linear models and are available at the core of the statistics toolbox in the R system for statistical computing. After reviewing the conceptual and computational features of these methods, a new implementation of zero-inflated and hurdle regression models in the functions zeroinfl() and hurdle() from the package pscl is introduced. It re-uses design and functionality of the basic R functions just as the underlying conceptual tools extend the classical models. Both model classes are able to incorporate over-dispersion and excess zeros - two problems that typically occur in count data sets in economics and the social and political sciences - better than their classical counterparts. Using cross-section data on the demand for medical care, it is illustrated how the classical as well as the zero-augmented models can be fitted, inspected and tested in practice. (author's abstract)Series: Research Report Series / Department of Statistics and Mathematics
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Yang, Congcong, Alfred Taudes, and Guozhi Dong. "Efficiency Analysis of European Freight Villages-Three Peers for Benchmarking." Department für Informationsverarbeitung und Prozessmanagement, WU Vienna University of Economics and Business, 2015. http://epub.wu.ac.at/4517/1/Efficiency_analysis_of_European_FVs%2Dthree_peers_for_benchmarking.pdf.
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Measuring the performance of Freight Villages (FVs) has important implications for logistics companies and other related companies as well as governments. In this paper we apply Data Envelopment Analysis (DEA) to measure the performance of European FVs in a purely data-driven way incorporating the nature of FVs as complex operations that use multiple inputs and produce several outputs. We employ several DEA models and perform a complete sensitivity analysis of the appropriateness of the chosen input and output variables, and an assessment of the robustness of the efficiency score. It turns out that about half of the 20 FVs analyzed are inefficient, with utilization of the intermodal area and warehouse capacity and level of goods handed the being the most important areas of improvement. While we find no significant differences in efficiency between FVs of different sizes and in different countries, it turns out that the FVs Eurocentre Toulouse, Interporto Quadrante Europa and GVZ Nürnberg constitute more than 90% of the benchmark share.Series: Working Papers on Information Systems, Information Business and Operations
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Yildirim, Evrim. "Development Of In Vitro Micropropagation Techniques For Saffron (crocus Sativus L.)." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608730/index.pdf.
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In vitro micropropagation of saffron (Crocus sativus L.) by using direct and indirect organogenesis was the aim of this study. Also, the effect of plant growth regulators on growth parameters, such as corm production, sprouting time and germination ratio were investigated in ex vitro conditions.
For in vitro regeneration of saffron, the effects of 2,4-D (2,4-dichlorophenoxyacetic acid) and BAP (6-benzylaminopurine) were tested initially. It was observed that 0,25 mg/L 2,4-D and 1 mg/L BAP combination was superior for indirect organogenesis while 1 mg/L 2,4-D and 1 mg/L BAP combination was favorable for direct organogenesis. During the improvement of direct organogenesis experiments, BAP (1 mg/L) without 2,4-D stimulated further shoot development.
For adventitious corm and root induction, NAA (naphthaleneacetic acid) and BAP combinations were tested. Although a few corm formations were achieved, root development was not observed with these treatments. Further experiments with the culture medium supplemented with 1 mg/L IBA (indole-3-butyric acid) and 5% sucrose was effective on obtaining contractile root formation and increasing corm number. As a result, the overall efficiency was calculated as 59.26% for contractile root formation, 35.19% for corm formation and 100% for shoot development.
In ex vitro studies, 50 mg/L IAA (indole-3-acetic acid) , 50 mg/L kinetin and 200 mg/L GA3 (gibberellic acid) were used. These applications were not as efficient as expected on assessed growth parameters.
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Benko, Michal. "Functional data analysis with applications in finance." Doctoral thesis, Humboldt-Universität zu Berlin, Wirtschaftswissenschaftliche Fakultät, 2007. http://dx.doi.org/10.18452/15585.
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An vielen verschiedenen Stellen der angewandten Statistik sind die zu untersuchenden Objekte abhängig von stetigen Parametern. Typische Beispiele in Finanzmarktapplikationen sind implizierte Volatilitäten, risikoneutrale Dichten oder Zinskurven. Aufgrund der Marktkonventionen sowie weiteren technisch bedingten Gründen sind diese Objekte nur an diskreten Punkten, wie zum Beispiel an Ausübungspreise und Maturitäten, für die ein Geschäft in einem bestimmten Zeitraum abgeschlossen wurde, beobachtbar. Ein funktionaler Datensatz ist dann vorhanden, wenn diese Funktionen für verschiedene Zeitpunkte (z.B. Tage) oder verschiedene zugrundeliegende Aktiva gesammelt werden. Das erste Thema, das in dieser Dissertation betrachtet wird, behandelt die nichtparametrischen Methoden der Schätzung dieser Objekte (wie z.B. implizierte Volatilitäten) aus den beobachteten Daten. Neben den bekannten Glättungsmethoden wird eine Prozedur für die Glättung der implizierten Volatilitäten vorgeschlagen, die auf einer Kombination von nichtparametrischer Glättung und den Ergebnissen der arbitragefreien Theorie basiert. Der zweite Teil der Dissertation ist der funktionalen Datenanalyse (FDA), speziell im Zusammenhang mit den Problemen, der empirischen Finanzmarktanalyse gewidmet. Der theoretische Teil der Arbeit konzentriert sich auf die funktionale Hauptkomponentenanalyse -- das funktionale Ebenbild der bekannten Dimensionsreduktionstechnik. Ein umfangreicher überblick der existierenden Methoden wird gegeben, eine Schätzmethode, die von der Lösung des dualen Problems motiviert ist und die Zwei-Stichproben-Inferenz basierend auf der funktionalen Hauptkomponentenanalyse werden behandelt. Die FDA-Techniken sind auf die Analyse der implizierten Volatilitäten- und Zinskurvendynamik angewandt worden. Darüber hinaus, wird die Implementation der FDA-Techniken zusammen mit einer FDA-Bibliothek für die statistische Software Xplore behandelt.In many different fields of applied statistics an object of interest is depending on some continuous parameter. Typical examples in finance are implied volatility functions, yield curves or risk-neutral densities. Due to the different market conventions and further technical reasons, these objects are observable only on a discrete grid, e.g. for a grid of strikes and maturities for which the trade has been settled at a given time-point. By collecting these functions for several time points (e.g. days) or for different underlyings, a bunch (sample) of functions is obtained - a functional data set. The first topic considered in this thesis concerns the strategies of recovering the functional objects (e.g. implied volatilities function) from the observed data based on the nonparametric smoothing methods. Besides the standard smoothing methods, a procedure based on a combination of nonparametric smoothing and the no-arbitrage-theory results is proposed for implied volatility smoothing. The second part of the thesis is devoted to the functional data analysis (FDA) and its connection to the problems present in the empirical analysis of the financial markets. The theoretical part of the thesis focuses on the functional principal components analysis -- functional counterpart of the well known multivariate dimension-reduction-technique. A comprehensive overview of the existing methods is given, an estimation method based on the dual problem as well as the two-sample inference based on the functional principal component analysis are discussed. The FDA techniques are applied to the analysis of the implied volatility and yield curve dynamics. In addition, the implementation of the FDA techniques together with a FDA library for the statistical environment XploRe are presented.
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Maier, Marco J. "DirichletReg: Dirichlet Regression for Compositional Data in R." WU Vienna University of Economics and Business, 2014. http://epub.wu.ac.at/4077/1/Report125.pdf.
Full textAbstract:
Dirichlet regression models can be used to analyze a set of variables lying
in a bounded interval that sum up to a constant (e.g., proportions, rates,
compositions, etc.) exhibiting skewness and heteroscedasticity, without
having to transform the data.
There are two parametrization for the presented model, one using the common
Dirichlet distribution's alpha parameters, and a reparametrization of the
alpha's to set up a mean-and-dispersion-like model.
By applying appropriate link-functions, a GLM-like framework is set up that
allows for the analysis of such data in a straightforward and familiar way,
because interpretation is similar to multinomial logistic regression.
This paper gives a brief theoretical foundation and describes the
implementation as well as application (including worked examples) of
Dirichlet regression methods implemented in the package DirichletReg (Maier,
2013) in the R language (R Core Team, 2013). (author's abstract)Series: Research Report Series / Department of Statistics and Mathematics
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Chao, Shih-Kang. "Quantile regression in risk calibration." Doctoral thesis, Humboldt-Universität zu Berlin, Wirtschaftswissenschaftliche Fakultät, 2015. http://dx.doi.org/10.18452/17223.
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Die Quantilsregression untersucht die Quantilfunktion QY |X (τ ), sodass ∀τ ∈ (0, 1), FY |X [QY |X (τ )] = τ erfu ̈llt ist, wobei FY |X die bedingte Verteilungsfunktion von Y gegeben X ist. Die Quantilsregression ermo ̈glicht eine genauere Betrachtung der bedingten Verteilung u ̈ber die bedingten Momente hinaus. Diese Technik ist in vielerlei Hinsicht nu ̈tzlich: beispielsweise fu ̈r das Risikomaß Value-at-Risk (VaR), welches nach dem Basler Akkord (2011) von allen Banken angegeben werden muss, fu ̈r ”Quantil treatment-effects” und die ”bedingte stochastische Dominanz (CSD)”, welches wirtschaftliche Konzepte zur Messung der Effektivit ̈at einer Regierungspoli- tik oder einer medizinischen Behandlung sind. Die Entwicklung eines Verfahrens zur Quantilsregression stellt jedoch eine gro ̈ßere Herausforderung dar, als die Regression zur Mitte. Allgemeine Regressionsprobleme und M-Scha ̈tzer erfordern einen versierten Umgang und es muss sich mit nicht- glatten Verlustfunktionen besch ̈aftigt werden. Kapitel 2 behandelt den Einsatz der Quantilsregression im empirischen Risikomanagement w ̈ahrend einer Finanzkrise. Kapitel 3 und 4 befassen sich mit dem Problem der h ̈oheren Dimensionalit ̈at und nichtparametrischen Techniken der Quantilsregression.Quantile regression studies the conditional quantile function QY|X(τ) on X at level τ which satisfies FY |X QY |X (τ ) = τ , where FY |X is the conditional CDF of Y given X, ∀τ ∈ (0,1). Quantile regression allows for a closer inspection of the conditional distribution beyond the conditional moments. This technique is par- ticularly useful in, for example, the Value-at-Risk (VaR) which the Basel accords (2011) require all banks to report, or the ”quantile treatment effect” and ”condi- tional stochastic dominance (CSD)” which are economic concepts in measuring the effectiveness of a government policy or a medical treatment. Given its value of applicability, to develop the technique of quantile regression is, however, more challenging than mean regression. It is necessary to be adept with general regression problems and M-estimators; additionally one needs to deal with non-smooth loss functions. In this dissertation, chapter 2 is devoted to empirical risk management during financial crises using quantile regression. Chapter 3 and 4 address the issue of high-dimensionality and the nonparametric technique of quantile regression.
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Burda, Maike M. "Testing for causality with Wald tests under nonregular conditions." Doctoral thesis, [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=968852432.
Full textBooks on the topic "Qh 244"
1
Constructing Grounded Theory. SAGE Publications, Limited, 2024.
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