Simple Series Research Articles

Design of a Fuzzy Time Series Forecasting Model for Hydro Power Generation

paper mainly deals with the design of forecasting model for Hydro power generation using Fuzzy time series. The fuzzy time series has recently received an increasing attention because of its capability of dealing with vague and incomplete data. There have been a variety of models developed either to improve forecasting accuracy or reduce computation overhead. This technique has been applied to forecast various fields and have been shown to forecast better than other models. Hence, in this paper fuzzy time series forecasting technique has been applied on hydro power generation data set. An algorithm is designed and based on the numerical calculations and graphical representations it reveals that Hydro Power generation can be forecasted by using Fuzzy Time Series. Singh (2008, 2009) presented the computational method of forecasting based on fuzzy time series have been developed to provide improved forecasting results to deal with the situation containing higher uncertainty due to large fluctuations in consecutive year's values in the time series data and having no visualization of trend or periodicity. He has developed the order three and higher order difference to use a time variant difference parameter on current state to forecast the next state. Ruey-Chyn Tsaur,(2012) developed the fuzzy time series-Markov chain approach for analyzing the linguistic or a small sample time series data is proposed to further enhance the predictive accuracy. In this method to transferred fuzzy time series data into fuzzy logic group, and using the obtained fuzzy logic group to derive a Markov chain transition matrix. Wangren Qiu et al., (2011) presented ensemble technique an effective method for improving the classification accuracy in data mining area. The ensemble technique was applied to fuzzy time series and improves that Song's and Chissom (1993a, b), Chen (1996) and Lee et al. (2009) models can be approximated by the proposed model via the limitation of the fuzzy weights. The impact on the performance of the proposal model is discussed. Both university enrollment and Shanghai stock index are chosen as the forecasting targets. The empirical results not only testify the above assertion, but also show that the proposed model can provide better overall forecasting results than the previous models with appropriate parameters. Enjian Bai (2011) presented a simple heuristic time-invariant fuzzy time series forecasting model, which was used to prediction accuracy of model observations to train the trend predictor in the training phase, and uses this trend predictor to generate forecasting values in the testing phase.

Analytical evaluation of the Marcus–Hush–Chidsey function using binomial expansion theorem and Error functions

A simple and straightforward analytical method is presented for calculating the Marcus–Hush–Chidsey function. We present here an alternative derivation method which leads to a simpler series analytical formula, based on the use of the binomial expansion theorem. The convergence of the series is tested by calculating concrete cases for arbitrary values of parameters. Comparison with available analytical results validates the accuracy and efficiency of this method.

Term Structure Forecasting of Government Bond Yields with Latent and Macroeconomic Factors: Do Macroeconomic Factors Imply Better Out‐of‐Sample Forecasts?

ABSTRACTThis study empirically examines the role of macroeconomic and stock market variables in the dynamic Nelson–Siegel framework with the purpose of fitting and forecasting the term structure of interest rate on the Japanese government bond market. The Nelson–Siegel type models in state‐space framework considerably outperform the benchmark simple time series forecast models such as an AR(1) and a random walk. The yields‐macro model incorporating macroeconomic factors leads to a better in‐sample fit of the term structure than the yields‐only model. The out‐of‐sample predictability of the former for short‐horizon forecasts is superior to the latter for all maturities examined in this study, and for longer horizons the former is still compatible to the latter. Inclusion of macroeconomic factors can dramatically reduce the autocorrelation of forecast errors, which has been a common phenomenon of statistical analysis in previous term structure models. Copyright © 2013 John Wiley & Sons, Ltd.

A simple but accurate method for study of radial variation of pump and signal intensities in single-mode erbium-doped dispersion-shifted as well as dispersion-flattened fiber amplifier

The doped fiber amplifier provides broadband amplification in case of multi-channel optical signals in long-haul communication systems. In this context, single-mode dispersion-shifted and dispersion-flattened fibers have emerged as potential candidates for the purpose of communication of information through fundamental mode. Consequently accurate but simple expression for the fundamental modal field in the doped fiber, both for the pump and the signal as well, is important for investigation of their variations with radial distance. Employing the simple but accurate power series expression of fundamental modal field for dispersion-shifted trapezoidal and dispersion-flattened step and graded W fibers, we estimate how the modal intensity changes with change of radial distance from the axis of such type of fiber in case of both the pump and signal intensities. Using some typical fibers of the said kind as examples, we show that our estimations by this simple formalism agree excellently with the numerical exact results. Our method requires little computations for the concerned calculations. Prescription of such simple but accurate formalism will benefit the system engineers who are working in the field of all optical technology.

A Run Length Transformation for Discriminating Between Auto Regressive Time Series

We describe a simple time series transformation to detect differences in series that can be accurately modelled as stationary autoregressive (AR) processes. The transformation involves forming the ...

Fractional modal power inside the core and excitation of fundamental mode by uniform light source in case of single-mode dispersion-shifted and dispersion-flattened fibers: Prediction by a simple technique

Employing the simple series expression for fundamental mode based on Chebyshev technique, we report simple but accurate formalism for the evaluation of the fractional modal power guided inside the core and the excitation efficiency of the mode by uniform light source in case of single-mode dispersion-shifted trapezoidal and dispersion-flattened graded and step W fibers. The values of these propagation parameters for such kind of fibers are not available in literature till date to the best of our knowledge. The formalism involves application of least square fitting method in order to formulate a linear relationship of the ratio of first and zero order modified Bessel functions with reciprocal of cladding decay parameter over a wide and practical range of its values, appropriate for single-mode guidance in such fibers. Analytical expressions for the concerned propagation characteristics are prescribed and the concerned estimations require little computations. Our results are found to match excellently with the available exact results. This accurate and user friendly formalism will benefit the system engineers working in the area of all optical technology.

The Making Evidence-Based Medicine Simple Series — Therapy Module

OPEN ACCESSJuly 15, 2013The Making Evidence-Based Medicine Simple Series — Therapy Module Michael Mojica, MD Michael Mojica, MD New York University School of Medicine Google Scholar More articles by this author https://doi.org/10.15766/mep_2374-8265.9478 SectionsAboutAbstract ToolsDownload Citations ShareFacebookTwitterEmail AbstractAbstract Introduction: The Making Evidence Based Medicine Simple Series is an evidence-based clinical practice curriculum. It consists of six modules that review the articles types addressing the most common clinical questions (i.e., diagnosis, therapy, harm, prognosis, meta-analysis, and clinical decision rules). Each module reviews an article from the medical literature using the Users Guide to Medical Literature criteria for validity, results, and applicability. Each modules includes a PowerPoint presentation with a script, a video of the presentation with narration, a quiz with answers, tips for teaching the module, a blank review form, and a completed critical article review for the article reviewed in the module. Methods: The Therapy Module reviews the appraisal of the validity, results, and applicability of a randomized clinical trial of steroid therapy for mild croup. The study addresses the following clinical question: In children with mild croup in the emergency department, will oral dexamethasone when compared to placebo result in a reduction in unscheduled return visits? In addition, this module reviews the following critical appraisal skills: (1) differentiating between a superiority, non-inferiority, and equivalence analysis, (2) identifying the role of randomization, allocation concealment, and blinding in reducing bias, (3) distinguishing between an intention to treat and per protocol analysis, (4) calculating absolute risk, absolute risk reduction, and relative risk from a 2 × 2 table, (5) distinguishing between clinical and statistical significance, and (6) calculating/interpreting a number needed to treat. Results: Evaluations by course participants have been extremely positive. Participants often comment that they have finally grasped important content that they have previously struggled with. The materials have been particularly useful to those who are leading a teaching session. Feedback from a 2013 course for pediatric emergency medicine fellows indicated that 92% of participants felt the Therapy Module was “extremely helpful.” In addition, 100% of participants agreed or strongly agreed that the modules improved their ability to appraise an article, and their ability to conduct evidence-based clinical practice. One-hundred percent also agreed or strongly agreed that the precourse materials were useful. Discussion: The Making Evidence Based Medicine Simple Series is a well-received evidence based clinical practice curriculum and the Therapy Module is an effective component of the series that can be used independently or with the other modules. Educational Objectives By the end of this session, learners will be able to: Evaluate the validity, results, and applicability of a therapy article.Develop a “clinical bottom line” for a therapy article.Describe the steps in a randomized controlled trial.Differentiate analysis types (i.e., superiority, non-inferiority, and equivalence studies).Outline a therapy question in population/patient, intervention/indicator, comparator/control, and outcome format.Understand the validity criteria for a therapy study.Define randomization, allocation concealment, and blinding.Identify the effects of randomization, allocation concealment, and blinding on bias.Distinguish between an intention to treat and per protocol analysis.Calculate absolute risk, absolute risk reduction, and relative risk from a 2 × 2 table.Calculate relative risk reduction and understand its limitation.Distinguish between clinical and statistical significance.Interpret statistical significance from a confidence interval of an absolute risk reduction and relative risk.Understand the applicability criteria for a therapy study.Calculate and interpret a number needed to treat and number needed to harm.Create a clinical bottom line for a therapy study. Sign up for the latest publications from MedEdPORTAL Add your email below FILES INCLUDEDReferencesRelatedDetails FILES INCLUDED Included in this publication: Critical Appraisal Form - Therapy - Blank.doc Critical Appraisal From - Dexamethasone for Mild Croup.pdf EBM Teaching Tips - General Approach to the Modules.pdf EBM Teaching Tips - Therapy.pdf Instructor's Guide - MESS Curriculum - Overview.pdf Instructor's Guide - MESS Curriculum - Therapy Module.pdf Lecture Notes - Therapy.pdf Lecture Slides - Therapy.pdf Lecture Slides - Therapy.ppt QUIZ ANSWERS Therapy.pdf QUIZ Therapy.pdf Video Screencast - Therapy.mp4 To view all publication components, extract (i.e., unzip) them from the downloaded .zip file. Download editor’s noteThis publication may contain technology or a display format that is no longer in use. Related The Making Evidence-Based Medicine Simple Series — Diagnostic Testing Module The Making Evidence-Based Medicine Simple Series — Therapy Module The Making Evidence-Based Medicine Simple Series — Harm Module The Making Evidence-Based Medicine Simple Series — Prognosis Module The Making Evidence-Based Medicine Simple Series — Meta-analysis Module The Making Evidence-Based Medicine Simple Series - Clinical Decision Rule Module Copyright & Permissions© 2013 Mojica. This is an open-access publication distributed under the terms of the Creative Commons Attribution-NonCommercial license.KeywordsEvidence-Based Clinical PracticeMeta-AnalysisJournal ClubDiagnostic TestingClinical Prediction RuleHarmPrognosisClinical Decision RuleTherapyEvidence-Based Medicine Disclosures None to report. Funding/Support None to report. Loading ...

The Making Evidence-Based Medicine Simple Series — Meta-analysis Module

Abstract Introduction The Making Evidence Based Medicine Simple Series is an evidence-based clinical practice curriculum. It consists of six modules that review the article types addressing the mos...

An extended singular spectrum transformation (SST) for the investigation of Kenyan precipitation data

Abstract. In this paper a change-point detection method is proposed by extending the singular spectrum transformation (SST) developed as one of the capabilities of singular spectrum analysis (SSA). The method uncovers change points related with trends and periodicities. The potential of the proposed method is demonstrated by analysing simple model time series including linear functions and sine functions as well as real world data (precipitation data in Kenya). A statistical test of the results is proposed based on a Monte Carlo simulation with surrogate methods. As a result, the successful estimation of change points as inherent properties in the representative time series of both trend and harmonics is shown. With regards to the application, we find change points in the precipitation data of Kenyan towns (Nakuru, Naivasha, Narok, and Kisumu) which coincide with the variability of the Indian Ocean Dipole (IOD) suggesting its impact of extreme climate in East Africa.

The Making Evidence-Based Medicine Simple Series — Diagnostic Testing Module

Abstract Introduction The Making Evidence Based Medicine Simple Series is an evidence-based clinical practice curriculum. It consists of six modules that review the articles types addressing the mo...

The Making Evidence-Based Medicine Simple Series - Clinical Decision Rule Module

Abstract Introduction The Making Evidence Based Medicine Simple Series is an evidence-based clinical practice curriculum. It consists of six modules that review the articles types addressing the mo...

Fourier Analysis of the Effect of Momentum Interpolation on the SIMPLE Series Formulated on a Collocated Grid

The error amplification matrices of three SIMPLE series formulated on a staggered grid and a collocated grid using three momentum interpolation methods are derived. The effects of grid layout and momentum interpolation methods on convergence properties of SIMPLE series are checked. The results indicate that the convergence conditions are available by damping out the highest and lowest errors. The SIMPLE series show almost identical convergence rates under a wide range of useful velocity relaxation factors, regardless of grid layout and interpolation method. However, the high-frequency reduction shows significant variation with grid layout and interpolation method, which maybe referred to in multigrid application.

Comparing the impact of time displaced and biased precipitation estimates for online updated urban runoff models

When an online runoff model is updated from system measurements, the requirements of the precipitation input change. Using rain gauge data as precipitation input there will be a displacement between the time when the rain hits the gauge and the time where the rain hits the actual catchment, due to the time it takes for the rain cell to travel from the rain gauge to the catchment. Since this time displacement is not present for system measurements the data assimilation scheme might already have updated the model to include the impact from the particular rain cell when the rain data is forced upon the model, which therefore will end up including the same rain twice in the model run. This paper compares forecast accuracy of updated models when using time displaced rain input to that of rain input with constant biases. This is done using a simple time-area model and historic rain series that are either displaced in time or affected with a bias. The results show that for a 10 minute forecast, time displacements of 5 and 10 minutes compare to biases of 60 and 100%, respectively, independent of the catchments time of concentration.

Maximum Reduction in Peak Voltage Using Stepped Currents to Deliver Charge to $RC$ Circuits

This brief analyzes the performance achievable by regularly sampled piecewise constant current waveforms in reducing the peak voltage across the driving terminals of an RC circuit when delivering a given charge over a given time duration into the terminals, as compared with using a fixed current. It is shown analytically for two and three current steps and numerically for more steps that the biggest achievable peak voltage reduction obtained with a simple series RC circuit cannot be exceeded with a more complicated RC circuit. Then the biggest peak voltage reduction that can be obtained is approximately 22.98% using either an infinite number of current steps of infinitesimal duration or a constant voltage drive. These are new basic results on RC circuits and have application to the design of neurostimulators.

The Making Evidence-Based Medicine Simple Series — Prognosis Module

OPEN ACCESSJune 6, 2013The Making Evidence-Based Medicine Simple Series — Prognosis Module Michael Mojica, MD Michael Mojica, MD New York University School of Medicine Google Scholar More articles by this author https://doi.org/10.15766/mep_2374-8265.9440 SectionsAbout ToolsDownload Citations ShareFacebookTwitterEmail AbstractAbstractThe Making Evidence-Based Medicine Simple Series is an evidence-based clinical practice curriculum. It consists of six modules reviewing the articles types addressing the most common clinical questions (i.e., diagnosis, therapy, harm, prognosis, meta-analysis, and clinical decision rules). Each module reviews an article using the Users Guide to Medical Literature criteria for validity, results, and applicability. Each modules includes a PowerPoint presentation with a script, a video of the presentation with narration, a quiz with answers, tips for teaching the module, a blank review form, and a completed critical article review for the article reviewed in the module.The prognosis module reviews the appraisal of the validity, results, and applicability of a prospective cohort study of an Australian population with osteoporotic fractures. The study addresses the following clinical question: Do patients over 60 years of age with an osteoporotic fracture, when compared to age and gender matched controls and followed over time, have in increased risk of all-cause mortality? In addition, this module reviews the following critical appraisal skills: (1) determining the difference between a prognostic and risk factor, (2) distinguishing between prevalence and incidence, (3) defining and interpreting standardized mortality ratios, (4) interpreting Kaplan-Meier survival curves, and (5) identifying factors suggestive of causality versus association. Educational Objectives By the end of this session, learners will be able to: Differentiate between prognostic factors and risk factors.Identify study designs applicable to prognosis studies.Outline a prognosis question in population/patient, intervention/indicator, comparator/control, and outcome format.Understand the validity criteria for a prognosis study.Distinguish between measures of frequency (i.e., prevalence and incidence).Define and calculate person-years.Interpret absolute mortality rates and life years lost.Define and interpret standardized mortality ratios.Interpret Kaplan-Meier survival curves.Understand the principles and utility of univariable and multivariable analyses.Interpret confidence intervals for precision and statistical significance.Identify factors suggestive of causality versus association.Understand the applicability criteria for a prognosis study.Develop a clinical bottom line for a prognosis study. Sign up for the latest publications from MedEdPORTAL Add your email below FILES INCLUDEDReferencesRelatedDetails FILES INCLUDED Included in this publication: Authors Instructions - MESS Curriculum - Overview.pdf Authors Instructions - MESS Curriculum - Prognosis Module.pdf Critical Article Review - Mortality after Osteoporotic Fracture - JAMA - 2009.pdf Critical Article Review Form - Prognosis.doc EBM Teaching Tips - General Approach to the Modules.pdf EBM Teaching Tips - Prognosis.pdf Lecture Script - Prognosis Studies.pdf Lecture Slides - Prognosis Studies.pdf Lecture Slides - Prognosis Studies.ppt Quiz - Prognosis.pdf Quiz Answers - Prognosis.pdf Video Screencast - Prognosis.mp4 To view all publication components, extract (i.e., unzip) them from the downloaded .zip file. Download editor’s noteThis publication may contain technology or a display format that is no longer in use. Related The Making Evidence-Based Medicine Simple Series — Diagnostic Testing Module The Making Evidence-Based Medicine Simple Series — Therapy Module The Making Evidence-Based Medicine Simple Series — Harm Module The Making Evidence-Based Medicine Simple Series — Prognosis Module The Making Evidence-Based Medicine Simple Series — Meta-analysis Module The Making Evidence-Based Medicine Simple Series - Clinical Decision Rule Module Copyright & Permissions© 2013 Mojica. This is an open-access publication distributed under the terms of the Creative Commons Attribution-NonCommercial license.KeywordsClinical Decision RuleJournal ClubEvidence-Based MedicineHarmEvidence-Based PracticePrognosisMolecular Diagnostic TestingMeta-AnalysisTherapy Disclosures None to report. Funding/Support None to report. Loading ...

Applying econometric techniques to hydrological problems in a large basin: Quantifying the rainfall–discharge relationship in the Burdekin, Queensland, Australia

• Studies rainfall–river discharge relationship within a large tropical river basin. • Compares different approaches to measuring areal rainfall and different models. • Finds no evidence of climate change having altered rainfall or river discharge. • Finds best models have coarse geographic and temporal scale. • Finds statistical selection and weighting of stations better than Thiessen Polygons. This study seeks to explore the relationship between rainfall and river discharge within a large river basin flowing into the waters surrounding the Great Barrier Reef (GBR), and to investigate the best method of measuring the relationship. This aim is addressed by focusing on three specific research questions: (A) Has there been any evidence that global climate change has impacted on either rainfall or river discharge resulting in any change to the relationship between these variables over time? (B) What is the best measure of rainfall to be used to quantify the rainfall–discharge relationship, including the optimal number of rain stations to be included in the sample? (C) What is the optimal temporal scale for measuring the relationship (ranging from fine scale monthly data, medium scale quarterly data, and coarse scale annual data)? Modern econometric time series techniques are utilised, and compared with results using an alternate technique developed by researchers from the bio-physical sciences; the widely used Thiessen Polygon method. Firstly, stationarity testing, using econometric unit root tests, did not find evidence to suggest that the data are non-stationary. Evidently, climate change has not had a measurable impact on rainfall or river discharge in the region during the period covered by this study. Secondly, the analysis shows that the when dealing with fairly simple models with a fairly small number of explanatory variables, those which best represent the river–discharge relationship are those using the coarser scales (both geographic and temporal). In other words, stronger and more robust results are derived from models using fewer rain stations, and annual data (rather than quarterly or monthly data). This approach provides a viable alternative that may be very useful in data-poor environments when it is not possible to use other more data-hungry modelling approaches. The econometric models provided a better explanation of the relationship than the Thiessen Polygon approach, whilst utilising data from a smaller number of rain stations. The most appropriate functional form was that using the natural logs of discharge as the dependent variable, and the relationship appears to be a fairly simple one, with the inclusion of lagged data from previous years not significantly improving the explanation provided by current year models. The approach demonstrates that simple time series models can be enriched by the incorporation of additional variables beyond rainfall levels; both temperatures and rainfall concentration were considered with the inclusion of a rainfall concentration index proving to significantly improve the explanatory power of the model for this study region.

Effect of glycosylation on the partition behavior of a human antibody in aqueous two‐phase systems

Human proteins are expressed in some hosts wrongly glycosylated or nonglycosylated. Although it is accepted that glycosylation contributes to the stability of the protein in solution, the effect of glycosylation on the stability of human antibodies is not fully understood. In this work, we present solubility studies of two human antibodies that have the same primary structure but different glycosylation pattern. The studies were done by monitoring the partitioning behavior of both proteins in a series of aqueous two-phase systems at and away the isoelectric point of the proteins and at different temperatures. Our studies show that in the absence of direct electrostatic forces, the partitioning behavior of the antibodies depends on the presence or absence of the polysaccharide chains. Overall, the nonglycosylated protein is less soluble than the glycosylated one. The potential of aqueous two-phase systems for the separation of the glycosylated and nonglycosylated proteins was also explored. A simple series of extractions seems to be enough to separate the glycosylated variety from the nonglycosylated one at high purity but low yields.

Dissolution Kinetics of Nanocrystals

A simple series of test-tube experiments is all it takes to quantify a largely neglected nano-effect responsible for a dramatic increase-by orders of magnitude-in the surface-area-normalized rate of dissolution of nanocrystals. Though the observed variation in this specific rate as a function of size is unprecedented, the effect may be rationalized in terms of the classic atomistic theory of crystal growth and dissolution.

Electroacoustic metamaterials: Achieving negative acoustic properties with shunt loudspeakers

Acoustic metamaterials constitute a new class of structures that exhibit acoustic properties not readily available in nature. These properties can be a negative mass density, expressing the opposition of the acceleration of a particle to the application of pressure, or a negative bulk modulus, signifying the rarefaction of the particle in reaction to a compression (resp. a condensation in reaction to a depression). However, these artificial behaviors result from a periodic arrangement of passive unit-cells (such as membranes and side holes), and not from individual “meta-properties” of each unit-cell. It is however possible to observe such intrinsic metamaterial properties out of a passive electroacoustic resonator. This concept encompasses a loudspeaker, connected to a specific electric load, thus altering the acoustic dynamics of the loudspeaker diaphragm when subject to an exogenous sound source. It is especially possible to achieve negative acoustic impedance at its diaphragm, thanks to the connection of passive electric shunt circuits, such as simple RLC series resonators. This paper aims at highlighting the metamaterial nature of such electroacoustic resonators through computational and experimental results, followed by discussions on ongoing developments.

Structure–activity relationships for ferriprotoporphyrin IX association and β-hematin inhibition by 4-aminoquinolines using experimental and ab initio methods

In order to probe structure–activity relationships of association with ferriprotoporphyrin IX (logK) and inhibition of β-hematin formation, a series of 4-aminoquinolines with varying substituents at the 7-position (X) have been synthesized. These have been further elaborated by introduction of two different R groups on the 4-amino nitrogen atom in the form of methyl (R=Me) and ethylamine (R=EtNH2) side chains. Data for a previously investigated series containing an N,N-diethyl-ethylamine side chain were also compared with the findings of this study. Experimentally, logK values for the simple 4-aminoquinoline series (R=H) were found to correlate with the hydrophobicity constant (π) of the group X. The logK values for the series with R=Me and EtNH2 were found to correlate with those of the series with R=H. The log of the 50% β-hematin inhibitory activity (logBHIA50) was found to correlate with logK and either meta (σm) or para (σp) Hammett constants for the series with R=Me and EtNH2, but not the simple series with R=H. To further improve predictability, correlations with ab initio electrostatic parameters, namely Mulliken and CHelpG charges were investigated. The best correlations were found with CHelpG charges which indicated that logK values can be predicted from the charges on atom H-8 and the group X in the quinolinium species computed in vacuum, while logBHIA50 values can be predicted from the CHelpG charges on C-7, C-8 and N-1 for the neutral species in vacuum. These correlations indicate that association and inhibition of β-hematin formation are separately determined. They also suggest that electron withdrawing groups at the 7-position, but not necessarily hydrophobic groups are required for hemozoin inhibition. The upshot is that the correlations imply that considerably more hydrophilic hemozoin inhibitors are feasible.