“Eyeballing” Trends in Climate Time Series: A Cautionary Note

2005 ◽  
Vol 18 (6) ◽  
pp. 886-891 ◽  
Author(s):  
Donald B. Percival ◽  
D. Andrew Rothrock
Keyword(s):  
Time Series ◽  
Linear Trend ◽  
Linear Regression Analysis ◽  
Incorrect Conclusion ◽  
Starting Point ◽  
Order Of Magnitude ◽  
Standard Linear ◽  
Climate Time Series ◽  
Level Of Significance

Abstract In examining a plot of a time series of a scalar climate variable for indications of climate change, an investigator might pick out what appears to be a linear trend commencing near the end of the record. Visual determination of the starting time of the trend can lead to an incorrect conclusion that the trend is significant when the assessment is based on standard linear regression analysis; in fact, a presumed level of significance of 5% can be smaller than the actual level by up to an order of magnitude. An alternative procedure is suggested that is more appropriate for assessing the significance of a trend in which the starting point is identified visually.

scholarly journals Determination of the Starting Point in Time Series for Trend Detection Based on Overlapping Trend

2016 ◽  
Vol 16 (6) ◽  
pp. 98-110
Author(s):  
Gao Xuedong ◽  
Gu Kan
Keyword(s):  
Time Series ◽  
Piecewise Linear ◽  
Negative Influence ◽  
Trend Detection ◽  
Computational Accuracy ◽  
Starting Point ◽  
Time Series Studies ◽  
Definition Of ◽  
Stage Characteristic

Abstract The traditional time series studies consider the time series as a whole while carrying on the trend detection; therefore not enough attention is paid to the stage characteristic. On the other hand, the piecewise linear fitting type methods for trend detection are lacking consideration of the possibility that the same node belongs to multiple trends. The above two methods are affected by the start position of the sequence. In this paper, the concept of overlapping trend is proposed, and the definition of milestone nodes is given on its base; these way not only the recognition of overlapping trend is realized, but also the negative influence of the starting point of sequence is effectively reduced. The experimental results show that the computational accuracy is not affected by the improved algorithm and the time cost is greatly reduced when dealing with the processing tasks on dynamic growing data sequence.

scholarly journals Analisis Pengaruh Faktor Kebutuhan Energi Listrik Tahun 2015 Terhadap Daya Yang Tersambung Dan Energi Yang Terjual Menggunakan Regresi Linear Sederhana (Studi Kasus Pada PT. PLN (Persero) Unit Area Pelayanan Dan Jaringan (APJ) Palembang)

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Nazori Suhandi ◽  
Irma Yuliawati ◽  
Indah Charista
Keyword(s):  
Data Mining ◽  
Time Series ◽  
Linear Regression ◽  
Linear Regression Analysis ◽  
Electric Energy ◽  
Electrical Energy ◽  
Regression Method ◽  
Linear Regression Method ◽  
Simple Linear Regression ◽  
Level Of Significance

<p class="SammaryHeader" align="center"><strong><em>Abstract</em></strong></p><p><em>The availability of electrical energy is a very important aspect and even become a parameter to support the successful development of a region. Proper management of electrical energy resources and directed clearly will make the potential possessed of an area developed and utilized optimally. Population growth and economic development of a region can be influenced by the use of electrical energy. The supply of electricity must be taken into account so that the electrical energy can be available in an amount that suits your needs. Demand for the use of electricity in Indonesia will always increase with economic growth in addition to the development of electrical energy is also influenced by the development of the population in terms of quantity of customers to be electricity. Predicting methods such as using time series method (Gustriansyah, 2017) or data mining methods. The purpose of this research is to know how to overcome the influence of electricity usage (VA) connected with electric energy sold (KWh). Research done by simple linear regression method to facilitate writer in processing data. Based on the calculation result using simple linear regression method can be concluded 99.2% of the variation of electric power connected can be explained by the variable amount of electrical energy sold. While the rest (100% - 99.2% = 0.8%) is explained by other causes. And the level of significance &lt;0.05 so that the regression model can be used to predict the electrical energy sold.</em></p><p><strong><em>Keywords : </em></strong><em>Linear regression, analysis, electrical energy</em></p><p class="SammaryHeader" align="center"> </p><p class="SammaryHeader" align="center"><strong><em>Abstrak</em></strong></p><p><em>Ketersediaan energi listrik merupakan aspek yang sangat penting dan bahkan menjadi suatu parameter untuk mendukung keberhasilan pembangunan suatu daerah. Pengelolaan sumber daya energi listrik yang tepat dan terarah dengan jelas akan menjadikan potensi yang dimiliki suatu wilayah berkembang dan termanfaatkan secara optimal. Pertumbuhan populasi dan perkembangan ekonomi suatu wilayah dapat dipengaruhi penggunaan energi listrik. Penyediaan listrik harus diperhitungkan sehingga energi listrik dapat tersedia dalam jumlah yang sesuai dengan kebutuhan Anda. Permintaan untuk penggunaan energi listrik di Indonesia akan selalu meningkat dengan pertumbuhan ekonomi disamping pengembangan energi listrik juga dipengaruhi oleh perkembangan populasi dalam hal kuantitas pelanggan yang akan dialiri listrik. </em><em>Metode untuk memprediksi seperti menggunakan metode time series (Gustriansyah, 2017) atau metode data mining.</em><em> Adapun tujuan dari penelitian ini adalah untuk mengetahui bagaimana cara mengatasi pengaruh penggunaan tenaga listrik (VA) yang terhubung dengan energi listrik yang terjual (KWh). Penelitian dilakukan dengan metode regresi linier sederhana agar memudahkan penulis dalam mengolah data. Berdasarkan hasil perhitungan menggunakan metode regresi linier sederhana dapat disimpulkan sebesar 99,2% dari variasi daya listrik yang terhubung dapat dijelaskan oleh variabel jumlah energi listrik yang terjual. Sedangkan sisanya (100% - 99,2% = 0,8%) dijelaskan oleh penyebab lain. Dan tingkat signifikansi &lt;0,05 sehingga model regresi dapat digunakan untuk memprediksi energi listrik yang terjual.</em></p><p align="left"><strong><em>Kata kunc</em></strong><em>i: Regresi linier, analisis, energi listrik</em></p>

scholarly journals Dynamical Analysis of Biological Signals with the 0–1 Test: A Case Study of the PhotoPlethysmoGraphic (PPG) Signal

2021 ◽  
Vol 11 (14) ◽  
pp. 6508
Author(s):  
Javier de Pedro-Carracedo ◽  
Ana María Ugena ◽  
Ana Pilar Gonzalez-Marcos
Keyword(s):  
Time Series ◽  
Dominant Frequency ◽  
Dynamical Analysis ◽  
Reconstruction Method ◽  
Deterministic System ◽  
Blood Oxygen Saturation ◽  
Starting Point ◽  
Biological Signals ◽  
Young Subjects

The 0–1 test distinguishes between regular and chaotic dynamics for a deterministic system using a time series as a starting point without appealing to any state space reconstruction method. A modification of the 0–1 test allows for the determination of a more comprehensive range of signal dynamic behaviors, particularly in the field of biological signals. We report the results of applying the test and study with more details the PhotoPlethysmoGraphic (PPG) signal behavior from different healthy young subjects, although its use is extensible to other biological signals. While mainly used for heart rate and blood oxygen saturation monitoring, the PPG signal contains extensive physiological dynamics information. We show that the PPG signal, on a healthy young individual, is predominantly quasi-periodic on small timescales (short span of time concerning the dominant frequency). However, on large timescales, PPG signals yield an aperiodic behavior that can be firmly chaotic or a prior transition via an SNA (Strange Nonchaotic Attractor). The results are based on the behavior of well-known time series that are random, chaotic, aperiodic, periodic, and quasi-periodic.

Development of Validated Stability Indicating HPTLC Method for Assay of Ozagrel and its Pharmaceutical Formulations

2018 ◽  
pp. 36-48 ◽  
Author(s):  
Vishal N Kushare ◽  
Sachin S Kushare
Keyword(s):  
High Performance ◽  
Linear Regression Analysis ◽  
Pharmaceutical Formulations ◽  
Base Hydrolysis ◽  
Assay Method ◽  
Related Substance ◽  
Stability Indicating ◽  
Regular Production ◽  
Hptlc Method

The present paper describes stability indicating high-performance thin-layer chromatography (HPTLC) assay method for Ozagrel in bulk drugs. The method employed TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of toluene: methanol: triethylamine (6.5: 4.0: 0.1 v/v/v). The system was found to give compact spot for Ozagrel (Rf value of 0.40 ± 0.010). Densitometric analysis of Ozagrel was carried out in the absorbance mode at 280 nm. The linear regression analysis data for the calibration plots showed good linear relationship with r2 = 0.999 with respect to peak area in the concentration range 30 - 120 ng/spot. The developed HPTLC method was validated with respect to accuracy, precision, recovery and robustness. Also to determine related substance and assay determination of Ozagrel that can be used to evaluate the quality of regular production samples. The developed method can also be conveniently used for the assay determination of Ozagrel in pharmaceutical formulations. The limits of detection and quantitation were 4.069 and 12.332 ng/spot, respectively by height. Ozagrel was subjected to acid and alkali hydrolysis, oxidation, photochemical and thermal degradation. The drug undergoes degradation under acidic, basic, oxidation and heat conditions. This indicates that the drug is susceptible to acid, base hydrolysis, oxidation and heat. Statistical analysis proves that the method is repeatable, selective and accurate for the estimation of said drug. The proposed developed HPTLC method can be applied for identification and quantitative determination of Ozagrel in bulk drug and tablet formulation.

Development of a method for multielemental determination in water by EDXRF with radioisotopic source of 238Pu.

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Camilo Fuentes Serrano ◽  
Juan Reinaldo Estevez Alvares ◽  
Alfredo Montero Alvarez ◽  
Ivan Pupo Gonzales ◽  
Zahily Herrero Fernandez ◽  
...  
Keyword(s):  
Thin Layer ◽  
Expanded Uncertainty ◽  
Considerable Decrease ◽  
X Ray ◽  
Precipitation Efficiency ◽  
Method Of Determination ◽  
Sensitivity Curves ◽  
Order Of Magnitude ◽  
Metrological Parameters

A method for determination of Cr, Fe, Co, Ni, Cu, Zn, Hg and Pb in waters by Energy Dispersive X Ray Fluorescence (EDXRF) was implemented, using a radioisotopic source of 238Pu. For previous concentration was employed a procedure including a coprecipitation step with ammonium pyrrolidinedithiocarbamate (APDC) as quelant agent, the separation of the phases by filtration, the measurement of filter by EDXRF and quantification by a thin layer absolute method. Sensitivity curves for K and L lines were obtained respectively. The sensitivity for most elements was greater by an order of magnitude in the case of measurement with a source of 238Pu instead of 109Cd, which means a considerable decrease in measurement times. The influence of the concentration in the precipitation efficiency was evaluated for each element. In all cases the recoveries are close to 100%, for this reason it can be affirmed that the method of determination of the studied elements is quantitative. Metrological parameters of the method such as trueness, precision, detection limit and uncertainty were calculated. A procedure to calculate the uncertainty of the method was elaborated; the most significant source of uncertainty for the thin layer EDXRF method is associated with the determination of instrumental sensitivities. The error associated with the determination, expressed as expanded uncertainty (in %), varied from 15.4% for low element concentrations (2.5-5 μg/L) to 5.4% for the higher concentration range (20-25 μg/L).

DETERMINASI PEMBIAYAAN MUSYARAKAH

Equity ◽  
2015 ◽  
Vol 18 (1) ◽  
pp. 19
Author(s):  
Regi Oktaviyori ◽  
Praptiningsih Praptiningsih
Keyword(s):  
Significant Influence ◽  
Hypothesis Test ◽  
Third Parties ◽  
Analysis Technique ◽  
Sample Amount ◽  
Level Of Significance ◽  
Fund Return

This study aims to examine the determination of musyarakah financing in Bank Syariah Mandiri (BSM) period March 2008-December 2011. The data is obtainedbased on bank finance reporting that at publication. It is gained sample amount of 44 months. The analysis technique used here is multiple linier regression and hypothesis test using t-statistic and F-statistic with level of significance 5%. The result of this research is Third Parties Fund (DPK) and return gives significantly on musyarakah financing. The return on asset is not significant to musyarakah financing. By simultaneous, musyarakah financing give significant influence on the level of Third Parties Fund, return and return on asset.

Identification of N-Substituted Triazolo-azetidines as Novel Antibacterials using pDualrep2 HTS Platform

2019 ◽  
Vol 22 (5) ◽  
pp. 346-354
Author(s):  
Yan A. Ivanenkov ◽  
Renat S. Yamidanov ◽  
Ilya A. Osterman ◽  
Petr V. Sergiev ◽  
Vladimir A. Aladinskiy ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Large Scale ◽  
Underlying Mechanism ◽  
Luciferase Assay ◽  
Reporter System ◽  
E Coli ◽  
Starting Point ◽  
High Concentrations ◽  
Mic Value

Aim and Objective: Antibiotic resistance is a serious constraint to the development of new effective antibacterials. Therefore, the discovery of the new antibacterials remains one of the main challenges in modern medicinal chemistry. This study was undertaken to identify novel molecules with antibacterial activity. Materials and Methods: Using our unique double-reporter system, in-house large-scale HTS campaign was conducted for the identification of antibacterial potency of small-molecule compounds. The construction allows us to visually assess the underlying mechanism of action. After the initial HTS and rescreen procedure, luciferase assay, C14-test, determination of MIC value and PrestoBlue test were carried out. Results: HTS rounds and rescreen campaign have revealed the antibacterial activity of a series of Nsubstituted triazolo-azetidines and their isosteric derivatives that has not been reported previously. Primary hit-molecule demonstrated a MIC value of 12.5 µg/mL against E. coli Δ tolC with signs of translation blockage and no SOS-response. Translation inhibition (26%, luciferase assay) was achieved at high concentrations up to 160 µg/mL, while no activity was found using C14-test. The compound did not demonstrate cytotoxicity in the PrestoBlue assay against a panel of eukaryotic cells. Within a series of direct structural analogues bearing the same or bioisosteric scaffold, compound 2 was found to have an improved antibacterial potency (MIC=6.25 µg/mL) close to Erythromycin (MIC=2.5-5 µg/mL) against the same strain. In contrast to the parent hit, this compound was more active and selective, and provided a robust IP position. Conclusion: N-substituted triazolo-azetidine scaffold may be used as a versatile starting point for the development of novel active and selective antibacterial compounds.

scholarly journals Non-Destructive Micromagnetic Determination of Hardness and Case Hardening Depth Using Linear Regression Analysis and Artificial Neural Networks

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 18
Author(s):  
Rahel Jedamski ◽  
Jérémy Epp
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Regression Analysis ◽  
Artificial Neural Networks ◽  
Linear Regression ◽  
Linear Regression Analysis ◽  
Case Hardening ◽  
Artificial Neural ◽  
Non Destructive

Non-destructive determination of workpiece properties after heat treatment is of great interest in the context of quality control in production but also for prevention of damage in subsequent grinding process. Micromagnetic methods offer good possibilities, but must first be calibrated with reference analyses on known states. This work compares the accuracy and reliability of different calibration methods for non-destructive evaluation of carburizing depth and surface hardness of carburized steel. Linear regression analysis is used in comparison with new methods based on artificial neural networks. The comparison shows a slight advantage of neural network method and potential for further optimization of both approaches. The quality of the results can be influenced, among others, by the number of teaching steps for the neural network, whereas more teaching steps does not always lead to an improvement of accuracy for conditions not included in the initial calibration.

New determinations of tides on the north-western Ross Ice Shelf

2020 ◽  
pp. 1-14
Author(s):  
Richard D. Ray ◽  
Kristine M. Larson ◽  
Bruce J. Haines
Keyword(s):  
Time Series ◽  
Tide Gauge ◽  
High Rate ◽  
Ice Shelf ◽  
Ross Ice Shelf ◽  
The North ◽  
Global Positioning ◽  
North Western

Abstract New determinations of ocean tides are extracted from high-rate Global Positioning System (GPS) solutions at nine stations sitting on the Ross Ice Shelf. Five are multi-year time series. Three older time series are only 2–3 weeks long. These are not ideal, but they are still useful because they provide the only in situ tide observations in that sector of the ice shelf. The long tide-gauge observations from Scott Base and Cape Roberts are also reanalysed. They allow determination of some previously neglected tidal phenomena in this region, such as third-degree tides, and they provide context for analysis of the shorter datasets. The semidiurnal tides are small at all sites, yet M2 undergoes a clear seasonal cycle, which was first noted by Sir George Darwin while studying measurements from the Discovery expedition. Darwin saw a much larger modulation than we observe, and we consider possible explanations - instrumental or climatic - for this difference.

scholarly journals Fluorescent Orthopalladated Complexes of 4-Aryliden-5(4H)-Oxazolones from the Kaede Protein: Synthesis and Characterization

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1238
Author(s):  
Eduardo Laga ◽  
David Dalmau ◽  
Sofía Arregui ◽  
Olga Crespo ◽  
Ana I. Jimenez ◽  
...  
Keyword(s):  
Intramolecular Interactions ◽  
Ortho Position ◽  
Fluorescent Properties ◽  
Ancillary Ligands ◽  
X Ray ◽  
Mononuclear Complexes ◽  
Fluorescence Measurements ◽  
Anionic Ligands ◽  
Order Of Magnitude

The goal of the work reported here was to amplify the fluorescent properties of 4-aryliden-5(4H)-oxazolones by suppression of the hula-twist non-radiative deactivation pathway. This aim was achieved by simultaneous bonding of a Pd center to the N atom of the heterocycle and the ortho carbon of the arylidene ring. Two different 4-((Z)-arylidene)-2-((E)-styryl)-5(4H)-oxazolones, the structures of which are closely related to the chromophore of the Kaede protein and substituted at the 2- and 4-positions of the arylidene ring (1a OMe; 1b F), were used as starting materials. Oxazolones 1a and 1b were reacted with Pd(OAc)2 to give the corresponding dinuclear orthometalated palladium derivates 2a and 2b by regioselective C–H activation of the ortho-position of the arylidene ring. Reaction of 2a (2b) with LiCl promoted the metathesis of the bridging carboxylate by chloride ligands to afford dinuclear 3a (3b). Mononuclear complexes containing the orthopalladated oxazolone and a variety of ancillary ligands (acetylacetonate (4a, 4b), hydroxyquinolinate (5a), aminoquinoline (6a), bipyridine (7a), phenanthroline (8a)) were prepared from 3a or 3b through metathesis of anionic ligands or substitution of neutral weakly bonded ligands. All species were fully characterized and the X-ray determination of the molecular structure of 7a was carried out. This structure has strongly distorted ligands due to intramolecular interactions. Fluorescence measurements showed an increase in the quantum yield (QY) by up to one order of magnitude on comparing the free oxazolone (QY < 1%) with the palladated oxazolone (QY = 12% for 6a). This fact shows that the coordination of the oxazolone to the palladium efficiently suppresses the hula-twist deactivation pathway.

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