Evaluation of the Impact of Selected Weighting Methods on the Results of the TOPSIS Technique

2019 ◽  
Vol 18 (06) ◽  
pp. 1821-1843 ◽  
Author(s):  
Roman Vavrek
Keyword(s):  
Standard Deviation ◽  
Comprehensive Evaluation ◽  
Weight Method ◽  
The Mean ◽  
Topsis Technique ◽  
The Impact ◽  
Weighting Methods ◽  
Adequate Method ◽  
Deviation Method

The present research deals with selected multi-criteria methods identified according to available literature sources as a suitable instrument for the comprehensive evaluation of a set of alternatives. Further, it focuses on a group of methods including Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), which is often associated in practice with the use of several subjective and objective methods for the determination of the weights of selected indicators. Accordingly, five of these objective methods are used in this research. The main contribution consists in emphasizing the differences between the results achieved through various methods for the determination of the weights of input indicators. Moreover, we restate the fact that the choice of an adequate method to weigh indicators significantly affects the overall results of the TOPSIS technique. The Coefficient of Variance method clearly identifies subjects in prominent positions. Subsequently, the Mean Weight method does not consider the structure of data and their variability, while focusing on all the indicators being equal. The results obtained via the Standard Deviation and the Statistical Variance Procedure methods are comparable with the results obtained for the identical weights of individual indicators, i.e., the Mean Weight method. Therefore, based on the overall results of our research for the determination of the weights of input indicators for the purposes of the TOPSIS technique, we recommend the use of the Standard Deviation method.

scholarly journals Development and Validation of an ICP-MS Method for Simultaneous Determination of Selected Metals in Electronic Cigarette Aerosol

2018 ◽  
Vol 28 (1) ◽  
pp. 2-13
Author(s):  
Shintaro Ohashi
Keyword(s):  
Standard Deviation ◽  
Nitric Acid ◽  
Simultaneous Determination ◽  
Propylene Glycol ◽  
Relative Standard Deviation ◽  
Icp Ms ◽  
Relative Standard ◽  
The Mean ◽  
The Impact

SummarySafety and quality standards for electronic cigarettes (e-cigarettes) have been introduced regionally. In 2016, the U.S. Food and Drug Administration (FDA) issued a rule to regulate e-cigarettes, requiring to report harmful and potentially harmful constituents (HPHCs). In the United Kingdom, the British Standards Institution (BSI) specified the metals to be monitored for e-cigarettes. In this study, a method was developed and validated for the simultaneous determination of 13 metals (Be, Al, Cr, Fe, Co, Ni, Cu, As, Se, Ag, Cd, Sn and Pb) in e-cigarette aerosol. Furthermore, matrix effects of major constituents in the aerosol were investigated using glycerol or 1,2-propylene glycol solutions. E-cigarette aerosol was generated by a rotary smoking machine according to CORESTA Recommended Method N° 81 and collected by an electrostatic precipitator coupled to an impinger containing nitric acid. The collected aerosol was dissolved in nitric acid and an aliquot of this solution was analyzed by inductively coupled plasma mass spectrometry (ICP-MS) equipped with a collision/reaction cell.The linearity of the calibration curve was observed in the range of 0.2 to 100 ng/mL for each analyte; the correlation coefficients were 0.998 or larger, the mean recovery of each standard level ranged from 92.6 to 104.5% and the relative standard deviation amounted to max. 9.5%. Accuracy, repeatability and specificity were validated by spiking three different amounts of analytes into e-cigarette aerosol; the mean recovery of each spiking level ranged from 88.7 to 110.3% with a relative standard deviation amounting to max. 9.2% for all analytes. Background contamination from aerosol generation and collection system existed for some analytes, especially for Al, Fe, Cu and Sn. The potential sources of contamination should be identified and controlled to reduce the impact of contamination on quantification. In addition, the actual values for samples should be reported with method blank statistics. Increase of the concentrations of glycerol and 1,2-propylene glycol in the prepared sample led to the overestimation of As and Se. The amount of polyols in the collected aerosol should be monitored and controlled for the accurate quantification of As and Se.

scholarly journals Management of Chipping Operations in Polish Forests

2020 ◽  
Vol 3 (1) ◽  
pp. 56
Author(s):  
Arkadiusz Gendek ◽  
Monika Aniszewska ◽  
Witold Zychowicz ◽  
Tadeusz Moskalik ◽  
Jan Malaťák ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Travel Distance ◽  
Operating Efficiency ◽  
Site Location ◽  
Work Shift ◽  
Work Site ◽  
The Mean ◽  
The Impact ◽  
Machine Base

The aim of the research was to verify the impact of selected parameters on the efficiency and organization of chipper operations. The paper analyzes chipping operations in Polish forests with a focus on work site location, overnight chipper location, chipper workload per site, fuel consumption, and work shift duration, as all of these factors may affect operating efficiency. The mean chipper travel distance between sites during a shift ranged from 4.74 km to 9.5 km (chippers moved on average every other day). The mean work shift duration was 12.4 h. At the end of a shift, the chippers traveled on average from 4.2 km to 6.3 km to an overnight location. At the beginning of a workday, the chippers were dispatched to sites at a distance of 2.5 km to 4.0 km. The average fuel consumption of the forwarder-mounted chippers was 16 L/h and that of the truck-mounted chipper was 7.7 L/h. It was found that the following actions have a decisive influence on the effectiveness of the operation of the chippers: determination of the size of individual tasks and the deployment of successive forest areas, indication of the proper location of the machine base, and the method of accessing the forest area.

Factors associated with mobility apprehension in persons with lower limb amputation

2020 ◽  
Vol 44 (4) ◽  
pp. 208-214
Author(s):  
Shannon L Mathis
Keyword(s):  
Standard Deviation ◽  
Lower Limb ◽  
Avoidance Behavior ◽  
Pain Catastrophizing ◽  
Lower Limb Amputation ◽  
Limb Amputation ◽  
Walking Ability ◽  
Factors Associated ◽  
The Mean ◽  
The Impact

Background: Factors that are related to mobility apprehension were measured in a sample of persons with lower-limb amputation. Objectives: The purpose was to determine whether intensity, interference, or catastrophizing are associated with mobility apprehension. Study design: Cross-sectional study. Methods: Persons with amputation of a lower limb who were attending a national limb loss conference were recruited to complete a survey. Subjects were administered the Tampa Scale for Kinesiophobia to measure mobility apprehension. The Brief Pain Inventory was administered to quantify the affect of pain on general activity, walking ability, and enjoyment of life. The Pain Catastrophizing Scale was administered to assess the tendency to ruminate and magnify pain sensations. A multivariable linear regression was performed to determine factors associated with mobility apprehension. Results: Fifty-three people with lower-limb amputation participated in the study. The mean (standard deviation) score for mobility apprehension was 34.2 (6.0). Mean (standard deviation) pain intensity and interference scores were 1.6 (1.7) and 2.5 (2.6), respectively. The mean (standard deviation) pain catastrophizing score was 9.1 (10). Pain catastrophizing was the only variable associated with higher mobility apprehension ( β = 0.31, p < 0.001, R2 = 0.32). Results suggest that for every one-point increase in the pain catastrophizing score, mobility apprehension will increase by 0.3 of a point. Conclusion: These preliminary results suggest that pain catastrophizing was related to mobility apprehension in this cohort of persons with lower-limb amputation. This relationship indicates that the exploration of avoidance behaviors, such as pain catastrophizing, may be useful when developing a program for physical rehabilitation. Clinical relevance Pain catastrophizing, an avoidance behavior, may be associated with higher levels of mobility apprehension in persons with major lower-limb amputation. Understanding the impact of fear-avoidance behavior will allow clinicians to identify individuals at risk for poor outcomes following amputation surgery and to develop psychological strategies to complement treatment.

Determination of Maleic Hydrazide Residues in Tobacco and Vegetables

1973 ◽  
Vol 56 (5) ◽  
pp. 1164-1172
Author(s):  
Milan Ihnat ◽  
Robert J Westerby ◽  
Israel Hoffman
Keyword(s):  
Standard Deviation ◽  
Present Method ◽  
Maleic Hydrazide ◽  
Collaborative Study ◽  
Official Method ◽  
Sample Weight ◽  
Relative Standard ◽  
The Mean ◽  
Pipe Tobacco

Abstract The distillation-spectrophotometric method of Hoffman for determining maleic hydrazide has been modified to include a double distillation and was applied to the determination of 1–30 ppm maleic hydrazide residues in tobacco and vegetables. Recoveries of 1–23 μg added maleic hydrazide were independent of weight of maleic hydrazide, but did depend on sample and sample weight. The following recoveries were obtained from 0.5 g sample: pipe tobacco, 84%; commercially dehydrated potato, 83%; cigar tobacco, 81%; dried potato, 76%; fluecured tobacco, 73%; dried carrot, 71%. In the absence of sample, the recovery was 82%. When appropriate standard curves were used, maleic hydrazide levels determined in tobacco samples were essentially independent of sample weight in the range 0.1–3 g. The mean relative standard deviation for a variety of field-treated and fortified tobacco samples containing 1–28 ppm maleic hydrazide was 3%. The precision and sensitivity of this procedure seem to be substantial improvements over official method 29.111–29.117. It is recommended that the present method be subjected to a collaborative study.

Fluorometric Determination of Selenium in Foods

1974 ◽  
Vol 57 (2) ◽  
pp. 368-372 ◽  
Author(s):  
Milan Ihnat
Keyword(s):  
Standard Deviation ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Food Samples ◽  
Fluorometric Method ◽  
Fluorometric Determination ◽  
Relative Standard ◽  
The Mean

Abstract A fluorometric method using 2,3-diaminonaphthalene for estimating selenium has been evaluated with regard to its applicability to food samples. Charring of the sample during digestion appeared to result in losses of native and added selenium from some samples, so a modified wet digestion procedure was introduced. Digestion first in nitric acid followed by a mixture of nitric-perchloric-sulfuric acids substantially reduced the incidence of sample charring for a variety of foods. The mean apparent recovery of selenium added as selenite or selenate at 100 and 500 ng levels to 0.1 and 1.0 g corn cereal, skim milk powder, and meat and 0.1 g fish was 101.0%; the actual recovery of the same levels of selenium from standard solutions was 96.6%. For a variety of samples containing 5—750 ng native or added selenium, the standard deviation as 4.7 + 1.95 X 10-2W ng, where W = ng selenium in the sample taken for analysis. The relative standard deviation (RSD) as a function of selenium weight (ng) was 50% (10), 6.7% (100), 4.3% (200), 3.1% (400), 2.7% (600), and 2.5% (800). The detection limit (weight of selenium at which RSD = 50%) was 10 ng at a mean blank level of 25 ng.

Radioisotope Dilution Technique for Determination of Vitamin B12 in Foods

1982 ◽  
Vol 65 (1) ◽  
pp. 85-88 ◽  
Author(s):  
Patrick J Casey ◽  
Keevin R Speckman ◽  
Frank J Ebert ◽  
William E Hobbs
Keyword(s):  
Standard Deviation ◽  
Vitamin B12 ◽  
Relative Standard Deviation ◽  
Extraction Procedure ◽  
Dilution Technique ◽  
Microbiological Method ◽  
Relative Standard ◽  
Wide Range ◽  
The Mean

Abstract A radioisotope dilution (RID) method for the determination of vitamin B12 is presented. The method combines a standard extraction procedure (AOAC 43.108,12th ed.) with a commercially available RID assay kit. The method was evaluated on a wide range of fortified and unfortified food products. Recovery studies on both groups yielded average recoveries of 98.1 and 95.8%, respectively. Reproducibility data generated from replicate analyses on both groups gave a relative standard deviation of 6.9% for the fortified group and 9.2% for the unfortified group. For the samples studied, the mean vitamin B12 content determined by the RID method was 8.01 μg/100 g vs imean of 7.54 μg/100 g by the AOAC microbiological method; the correlation coefficient was r = 0.983.

A simple spectroturbidimetric method for the determination of the fat content of homogenized ice-cream mixes

1962 ◽  
Vol 29 (1) ◽  
pp. 47-53 ◽  
Author(s):  
J. D. S. Goulden ◽  
P. Sherman
Keyword(s):  
Standard Deviation ◽  
Ice Cream ◽  
Fat Content ◽  
Fat Globule ◽  
The Mean ◽  
Simple Filter

SummaryA rapid spectroturbidimetric method for the determination of the fat content of homogenized ice-cream mixes using a simple filter absorptiometer has been devised. Turbidities are measured at two different wavelengths to allow for changes in the degree of homogenization. The standard deviation of the differences from the values obtained by the Werner-Schmid method was found to be 2·5% of the mean fat content value. The method also enables the mean fat globule diameter to be determined.

Ion Exchange Separations and Atomic Absorption Determination of Trace Metals in Ores after Basic Fusion

1972 ◽  
Vol 26 (2) ◽  
pp. 302-305 ◽  
Author(s):  
T. W. Freudiger ◽  
C. T. Kenner
Keyword(s):  
Standard Deviation ◽  
Ion Exchange ◽  
Metal Ions ◽  
Atomic Absorption ◽  
Strong Acid ◽  
Ion Exchange Resin ◽  
High Concentration ◽  
The Mean ◽  
Trace Constituents

The determination of trace constituents in ores by atomic absorption after basic fusion and solution in strong acid is erratic due to the light scattering and aspirator clogging of the high concentration of sodium salts. The sodium is separated from the trace constituents using a column procedure and an iminodiacetate chelating ion exchange resin which will retain di- and trivalent metal ions at pH values above 6.0 but will not retain alkali metal ions. The trace constituents are determined by atomic absorption after elution with HCl. The precision (standard deviation of the mean) of the atomic absorption method is increased at least fivefold by the resin separation and the method is applicable to concentrations in the low ppm range. The standard deviation of the mean for an NBS sample containing 0.007% Cu is 0.0004%.

scholarly journals Validation of SCIAMACHY HDO/H<sub>2</sub>O measurements using the TCCON and NDACC-MUSICA networks

2015 ◽  
Vol 8 (4) ◽  
pp. 1799-1818 ◽  
Author(s):  
R. A. Scheepmaker ◽  
C. Frankenberg ◽  
N. M. Deutscher ◽  
M. Schneider ◽  
S. Barthlott ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Hydrological Cycle ◽  
Source Region ◽  
Total Carbon ◽  
Atmospheric Composition ◽  
The Tibetan Plateau ◽  
Wet Season ◽  
Data Set ◽  
The Mean ◽  
The Impact

Abstract. Measurements of the atmospheric HDO/H2O ratio help us to better understand the hydrological cycle and improve models to correctly simulate tropospheric humidity and therefore climate change. We present an updated version of the column-averaged HDO/H2O ratio data set from the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY). The data set is extended with 2 additional years, now covering 2003–2007, and is validated against co-located ground-based total column δD measurements from Fourier transform spectrometers (FTS) of the Total Carbon Column Observing Network (TCCON) and the Network for the Detection of Atmospheric Composition Change (NDACC, produced within the framework of the MUSICA project). Even though the time overlap among the available data is not yet ideal, we determined a mean negative bias in SCIAMACHY δD of −35 ± 30‰ compared to TCCON and −69 ± 15‰ compared to MUSICA (the uncertainty indicating the station-to-station standard deviation). The bias shows a latitudinal dependency, being largest (∼ −60 to −80‰) at the highest latitudes and smallest (∼ −20 to −30‰) at the lowest latitudes. We have tested the impact of an offset correction to the SCIAMACHY HDO and H2O columns. This correction leads to a humidity- and latitude-dependent shift in δD and an improvement of the bias by 27‰, although it does not lead to an improved correlation with the FTS measurements nor to a strong reduction of the latitudinal dependency of the bias. The correction might be an improvement for dry, high-altitude areas, such as the Tibetan Plateau and the Andes region. For these areas, however, validation is currently impossible due to a lack of ground stations. The mean standard deviation of single-sounding SCIAMACHY–FTS differences is ∼ 115‰, which is reduced by a factor ∼ 2 when we consider monthly means. When we relax the strict matching of individual measurements and focus on the mean seasonalities using all available FTS data, we find that the correlation coefficients between SCIAMACHY and the FTS networks improve from 0.2 to 0.7–0.8. Certain ground stations show a clear asymmetry in δD during the transition from the dry to the wet season and back, which is also detected by SCIAMACHY. This asymmetry points to a transition in the source region temperature or location of the water vapour and shows the added information that HDO/H2O measurements provide when used in combination with variations in humidity.

scholarly journals DOES CASSINI ALLOW ONE TO MEASURE RELATIVISTIC ORBITAL EFFECTS IN THE SATURNIAN SYSTEM OF SATELLITES?

2007 ◽  
Vol 16 (01) ◽  
pp. 11-17 ◽  
Author(s):  
LORENZO IORIO
Keyword(s):  
Data Sets ◽  
Zonal Harmonics ◽  
Low Degree ◽  
Saturnian System ◽  
Order Of Magnitude ◽  
General Relativistic ◽  
The Mean ◽  
Natural Satellites ◽  
The Impact

In this paper we address the following question: do the recent advances in the orbit determination of the major natural satellites of Saturn obtained with the analysis of the first data sets from the Cassini spacecraft allow to detect the general relativistic gravitoelectric orbital precessions of the mean longitudes of such moons? The answer is still negative. The present-day down-track accuracy is adequate for Mimas, Enceladus, Thetys, Dione, Rhea and Titan and inadequate for Hyperion, Iapetus and Phoebe. Instead, the size of the systematic errors induced by the mismodeling in the key parameters of the Saturnian gravitational field like the even zonal harmonics Jℓ are larger than the relativistic down-track shifts by about one order of magnitude, mainly for the inner satellites like Mimas, Enceladus, Thetys, Dione, Rhea, Titan and Hyperion. Instead, Iapetus and Phoebe are not notably affected by such kind of perturbations. Moreover, the bias due to the uncertainty in Saturn's GM is larger than the relativistic down-track effects for all such moons up to two orders of magnitude (Phoebe). Thus, it would be impossible to separately analyze the mean longitudes of each satellite. Proposed linear combinations of the satellites' mean longitudes would allow to cancel out the impact of the mismodeling in the low-degree even zonal harmonics and GM, but the combined down-track errors would be larger than the combined relativistic signatures by a factor 103.

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