Simple Difference Method Research Articles

Detected and projected temperature changes in the area of Mediterranean Montenegro

AbstractThe goal of this research is to present the results of a detailed analysis of detected and projected temperature changes in Montenegro. A total of 10 temperature parameters from 18 meteorological stations were used. Initially, an analysis of temperature changes during the instrumental period (1961–2020) was conducted, followed by the results of high‐resolution (12.5 km) bias‐corrected projections from the regional ALADIN, REMO and CCLM4 models for the period 2021–2100, according to the RCP4.5 and RCP8.5 scenarios (representative concentration pathways). The simple difference method and trend method were employed for research purposes. Compared with the period 1961–1990, the highest temperature increase during 1991–2020 is observed in summer (TSu), while the rates of increase were slower in spring, winter and autumn (TSp, TW and TA). The average annual maximum temperature (TYx) registered a higher increase compared with the average minimum (TYn). Frosty days (FD) decreased, while the number of summer and tropical days (SU and TD) increased. The projection results indicate that the period 2021–2050 is expected to be warmer, the period 2051–2080 even warmer, and the period 2081–2100 is expected to be the warmest. In the last analysed period (2081–2100), according to the RCP8.5 scenario, the average TSu is expected to be higher by 3.7–4.6°C (CCLM4), 4.1–4.7°C (ALADIN) and 4.7–5.8°C (REMO), with an anticipated increase in TW ranging between 3.3–4.5°C (ALADIN), 3.6–5.4°C (CCLM4) and 3.4–5.6°C (REMO). In the period 2021–2100, according to the RCP4.5 scenario, the expected average trend values for TYx (TYn) are expected to be (°C/decade) 0.24 (0.26), 0.16 (0.12) and 0.20 (0.23) for the ALADIN, REMO and CCLM4 models, respectively, and according to the RCP8.5 scenario, 0.47 (0.52), 0.63 (0.57) and 0.51 (0.53), respectively. These findings have implications for planning mitigation and adaptation measures to address climate change, particularly in strategic economic sectors such as tourism, agriculture and water management in Montenegro.

An efficient variance-based global sensitivity index based on C-DRM and Taylor expansion

Sensitivity analysis plays an important role in quantifying the impact of input uncertainty on model response uncertainty. Through sensitivity analysis, we can grasp the crucial parameters and gain a deeper understanding of the model behavior. In this paper, an effective analytical solution for solving the variance-based global sensitivity index is proposed. Firstly, the original performance function is approximated as the sum of a series of univariate functions using the conventional dimensional reduction method (C-DRM). Then, the Taylor series expansion is used to expand the univariate function as unary linear function and unary quadratic functions. Finally, the analytical solutions of the variance-based global sensitivity index based on unary linear function and unary quadratic functions are derived respectively. The computational cost of the proposed method is completely concentrated on the calculation of the partial derivative information of the performance function with respect to each variable. As long as the partial derivative information is obtained, the variance-based global sensitivity index can be obtained directly by the proposed method without any additional computational cost. For simple explicit performance functions, the derivative information can be directly derived analytically. For complex explicit or implicit performance functions, the derivative information can be estimated by some simple numerical difference methods. Five examples are studied to investigate the accuracy and efficiency of the proposed method.

Estimación del exceso de muertes reportadas total en el año 2020 versus el reporte de fallecidos por COVID-19 (SARS-CoV-2) en el Perú durante los meses de marzo, abril y mayo del 2020

Methods: We compared the gap between the National Death System (SINADEF) with the oficial reported deaths from COVID -19 from march 1st to  may 31th, 2020; Violent deaths (homicide, suicide, traffic accident; other accidents and unknown deaths) were excluded. To estimate the deaths baseline was used a seasonal linear regression,  from January 1st, 2017 to December 31th, 2019 with a 95% confidence intervals. The deaths reported in the National Death System was compared with the baseline deaths. The excess of deaths reported was estimated by “Simple Difference method”. Results: The research outcomes showed that the excess of total deaths, from 1st March to 31th may, 2020 is 2.24 times greater than the oficial number of deaths reported by COVID-19. Conclusions: The finded differences may be associated directly with a unregistered deaths by COVID-19 and another general death causes related with failures in our Public Health Sistem during the Pandemic period.

Individual changes in visual performance in non-demented Parkinson's disease patients: a 1-year follow-up study.

Cognitive deficits in Parkinson's disease (PD) are heterogeneous entities, and the cognitive status fluctuates over time. However, individual changes in longitudinal cognitive performance in PD are not fully understood. We evaluated three visual indices (visuoperception, visuoconstruction, and visuospatial ability) and four cognitive domains (attention/working memory, executive function, memory, and language) at baseline (Time1) and at 1-year follow-up (Time2) in 36 patients with PD and 32 healthy controls (HCs). To explore the magnitude and frequency of cognitive changes, we analyzed data using the simple difference method and the standardized regression-based method. We also explored the correlations between changes in test scores and several clinical predictors, using logistic regression analysis. At 1 year, patients with PD showed higher rates of change in scores on several cognitive tests, especially the Incomplete Letters test of visuoperception, compared to HCs. After adjusting for demographic variables, the visuoperceptual change was 61.1% overall, with the largest effect size. The changes in scores of visuoperception correlated with those of memory (r = 0.672, p < 0.001), language (r = 0.389, p < 0.05), and visuospatial ability (r = 0.379, p < 0.05). The severity of olfactory disturbance, the MDS-UPDRS Part I score, and younger PD onset predicted the significant changes observed in the Incomplete Letters test scores. Visuoperception changed more in non-demented PD patients than in HCs at 1-year follow-up. The changes in visuoperception could relate to involvement of the ventral occipitotemporal pathway, the more widespread temporal lobe, and brain reserve in PD.

Credible Methods for Evaluating the Impacts of Amil Programs

Existing studies on the impacts of amil programs are still rare and potentially contain bias in their impact estimates. This paper explains the selection problem common to simple difference method employed by these studies. Then this paper introduces two evaluation designs, difference-indifferences and randomized experiment, that can more credibly estimate program impacts, and still simple enough to be independently conducted by amil institutions.

A simple difference method for lattice Boltzmann algorithm to simulate conjugate heat transfer

In the present paper, a simple difference method for lattice Boltzmann algorithm is proposed to simulate conjugate heat transfer problems. In the conventional lattice Boltzmann method (LBM), the informations including temperature and heat flux exchange directly between two different media through distribution function during the streaming process, however, the continuity of heat flux at the interface between two different media cannot be guaranteed in this process. Different with the conventional LBM, we consider that the nodes near the interface get the distribution functions from the interface during the streaming process across the interface. The distribution functions at the interface can be obtained by coupling the interface conditions of temperature and heat flux with non-equilibrium extrapolation. Four test cases are used to validate the present method, including both steady and transient conjugate heat transfer with flat or curved interfaces. The results show that the present method is very easy to implement, and feasible for both steady and transient heat transfer problems. In addition, for simplicity, by approximating the real interface with a staircase shaped line, the present method can deal with curved interface easily and the results show the approximation will not contribute obvious error to the final results.

Rendimiento menor al esperado en Educación Secundaria Obligatoria: comparación de métodos estadísticos para su identificación en España

El presente estudio realiza una comparación de los métodos estadísticos más empleados en la detección del alumnado con rendimiento menor al esperado; concretamente el método de diferencias estandarizadas, el método de residuales de regresión y el método Rasch. Se empleó una muestra de 1182 alumnos de primer y segundo curso de Enseñanza Secundaria Obligatoria de 8 centros educativos de la provincia de Alicante. Los resultados muestran un porcentaje que oscila entre el 14.55% y el 30.37% de alumnos con rendimiento menor al esperado detectados en función del método estadístico empleado, siendo el método Rasch el que más alumnos identifica. Asimismo, se detectaron diferencias estadísticamente significativas entre el género y el tipo de alumnado (con rendimiento normal y con rendimiento menor al esperado), mientras que no se detectaron diferencias en función del curso y el tipo de alumnado. Este estudio confirma la importancia de conocer cómo afectan las propiedades de distintos métodos estadísticos en la detección del alumnado con rendimiento menor al esperado, así como sus principales implicaciones educativas.

Underachievement in Compulsory Secondary Education: a comparison of statistical methods for identification in Spain

This study compares the statistical methods employed for detecting underachievement, specifically the simple difference method, the regression method and the Rasch method. A sample of 1182 first- and second-year secondary students from 8 high schools in the province of Alicante participated in the study. The results showed a percentage of underachieving students that varies from 14.55% to 30.37%, depending on the statistical method employed. The Rasch method identified the highest number of underachieving students. Statistically significant differences were found between gender and type of student-underachieving and non-underachieving; however, no significant differences were detected between the course and type of student. This study confirms the importance of knowing the measurement properties of the statistical methods, how they affect the detection of underachieving students, and the main educational implications.

Underachievement in Compulsory Secondary Education: a comparison of statistical methods for identification in Spain

This study compares the statistical methods employed for detecting underachievement, specifically the simple difference method, the regression method and the Rasch method. A sample of 1182 first- and second-year secondary students from 8 high schools in the province of Alicante participated in the study. The results showed a percentage of underachieving students that varies from 14.55% to 30.37%, depending on the statistical method employed. The Rasch method identified the highest number of underachieving students. Statistically significant differences were found between gender and type of student-underachieving and non-underachieving; however, no significant differences were detected between the course and type of student. This study confirms the importance of knowing the measurement properties of the statistical methods, how they affect the detection of underachieving students, and the main educational implications.

Dynamic simulation and 2D multiple scales and multiple sources within basin geothermal field

In order to accurately describe the geothermal field within a basin, it is necessary to divide it into the normal geothermal field and additional geothermal field. For the accuracy by describing of the additional geothermal field, grids need to be increased. Traditional unequal interval difference method can be used to solve this problem, which has to increase grids within the unnecessary area, so as to make the calculated amount larger. Moreover, the calculation cannot be operated by the computer when there are several anomalous areas. This paper has solved simple difference method by focusing on local grids increased by introducing the method of virtual points. The comparison and analysis of the method show clearly that its precision is within a reasonable error range, whereas the calculation amount decreases obviously. The application of this method into the paleo-thermal field simulation in Dongying Depression, Shandong Province, China is effective in the hybrid simulation of the multiple scales geothermal field model within this area successfully.

Effects of Practice on the Wechsler Adult Intelligence Scale-IV Across 3- and 6-Month Intervals

A total of 54 participants (age M = 20.9; education M = 14.9; initial Full Scale IQ M = 111.6) were administered the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) at baseline and again either 3 or 6 months later. Scores on the Full Scale IQ, Verbal Comprehension, Working Memory, Perceptual Reasoning, Processing Speed, and General Ability Indices improved approximately 7, 5, 4, 5, 9, and 6 points, respectively, and increases were similar regardless of whether the re-examination occurred over 3- or 6-month intervals. Reliable change indices (RCI) were computed using the simple difference and bivariate regression methods, providing estimated base rates of change across time. The regression method provided more accurate estimates of reliable change than did the simple difference between baseline and follow-up scores. These findings suggest that prior exposure to the WAIS-IV results in significant score increments. These gains reflect practice effects instead of genuine intellectual changes, which may lead to errors in clinical judgment.

Frequency-difference electrical impedance tomography: Phantom imaging experiments

Frequency-difference electrical impedance tomography (fdEIT) using a weighted voltage difference has been proposed as a means to provide images of admittivity changes at different frequencies. This weighted difference method is an effective way to extract anomaly information while eliminating background effects by unknown boundary geometry, uncertainty in electrode positions and other systematic measurement artefacts. It also properly handles the interplay between conductivity and permittivity in measured boundary voltage data. Though the proposed fdEIT algorithm is promising for applications such as detection of hemorrhagic stroke and breast cancer, more validation studies are needed. In this paper, we performed two-and three-dimensional numerical simulations and phantom experiments. Backgrounds of imaging objects were either saline or carrot pieces suspended in saline. We used carrot pieces to simulate a more realistic frequency-dependent admittivity distribution. Test objects were banana, potato or conductive gel with known admittivity spectra. When the background was saline, both simple and weighted difference approaches produced reasonably accurate images. The weighted difference method yielded better images from two-dimensional imaging objects with background of carrot pieces. For the three-dimensional head-shaped phantom, the advantage of the weighted frequency difference method over the simple difference method is not as obvious as in the case of the two-dimensional phantom. It is unclear if this is due to measurement errors or limitations in the linear algorithm. Further refinement and validation of the frequency difference image reconstructions are currently in progress.

Independent Component Analysis-Based Background Subtraction for Indoor Surveillance

In video surveillance, detection of moving objects from an image sequence is very important for target tracking, activity recognition, and behavior understanding. Background subtraction is a very popular approach for foreground segmentation in a still scene image. In order to compensate for illumination changes, a background model updating process is generally adopted, and leads to extra computation time. In this paper, we propose a fast background subtraction scheme using independent component analysis (ICA) and, particularly, aims at indoor surveillance for possible applications in home-care and health-care monitoring, where moving and motionless persons must be reliably detected. The proposed method is as computationally fast as the simple image difference method, and yet is highly tolerable to changes in room lighting. The proposed background subtraction scheme involves two stages, one for training and the other for detection. In the training stage, an ICA model that directly measures the statistical independency based on the estimations of joint and marginal probability density functions from relative frequency distributions is first proposed. The proposed ICA model can well separate two highly-correlated images. In the detection stage, the trained de-mixing vector is used to separate the foreground in a scene image with respect to the reference background image. Two sets of indoor examples that involve switching on/off room lights and opening/closing a door are demonstrated in the experiments. The performance of the proposed ICA model for background subtraction is also compared with that of the well-known FastICA algorithm.

Discovering patterns of achievement in Hong Kong students: An application of the Rasch measurement model

Researchers have warned of the need to identify accurately students who are underachieving in Hong Kong, particularly among the gifted group. When comparing the relative effectiveness of three methods for estimating the proportion of underachievement, the absolute split method, using an arbitrary upper and lower limits for estimates of both performance and ability, is more useful for identifying gifted underachievers than the simple difference method (where standardized performance scores are subtracted from standardized ability scores) or the regression method. In contrast, the latter two methods are more useful for identifying underachievers at all levels of ability. All three methods, however, depend on measurements that are invariant, unidimensional and additive. With the advent of modern measurement theory using Rasch measurement models, it is now possible to satisfy these requirements. In this study, a sample of Primary 5 students in Hong Kong (n = 957) were asked to complete a test of mathematical achievement and the Ravens Progressive Matrices test in order to estimate the proportion of students who are underachieving at all levels of ability. Measurement scales were created using Rasch models for partial credit and dichotomous responses for each variable, respectively, and students placed on each scale according to their responses. Because the results are based on measurement scales that are invariant between persons, the identification of underachievement in these students across all levels of ability can be regarded as objective rather than sample dependent.

A Multispectral Technique for Detecting Low-Level Cloudiness near Sunrise

Abstract A technique using the Geostationary Operational Environmental Satellite (GOES) sounder radiance data has been developed to improve detection of low clouds and fog just after sunrise. The technique is based on a simple difference method using the shortwave (3.7 μm) and longwave (11.0 μm) window bands in the infrared range of the spectrum. The time period just after sunrise is noted for the difficulty in being able to correctly identify low clouds and fog over land. For the GOES sounder cloud product this difficulty is a result of the visible reflectance of the low clouds falling below the “cloud” threshold over land. By requiring the difference between the 3.7- and the 11.0-μm bands to be greater than 5.0 K, successful discrimination of low clouds and fog is found 85% of the time for 21 cases from 14 September 2005 to 6 March 2006 over the GOES-12 sounder domain. For these 21 clear and cloudy cases the solar zenith angle ranged from 87° to 77°; however, the range of solar zenith angles for cloudy cases was from 85° to 77°. The success rate further improved to 95% (20 out of 21 cases) by including a difference threshold of 5.0 K between the 3.7- and 4.0-μm bands, requiring that the 11.0-μm band be greater than 260 K, and limiting the test to fields of view where the surface elevation is below 999 m. These final three limitations were needed to more successfully deal with cases involving snow cover and dead vegetation. To ensure that only the time period immediately after sunrise is included the solar zenith angle threshold for application of these tests is between 89° and 70°.

Development of WAIS-III General Ability Index Minus WMS-III Memory Discrepancy Scores

Analysis of the discrepancy between intellectual functioning and memory ability has received some support as a useful means for evaluating memory impairment. In recent additions to Wechlser scale interpretation, the WAIS-III General Ability Index (GAI) and the WMS-III Delayed Memory Index (DMI) were developed. The purpose of this investigation is to develop base rate data for GAI-IMI, GAI-GMI, and GAI-DMI discrepancy scores using data from the WAIS-III/WMS-III standardization sample (weighted N = 1250). Base rate tables were developed using the predicted-difference method and two simple-difference methods (i.e., stratified and non-stratified). These tables provide valuable data for clinical reference purposes to determine the frequency of GAI-IMI, GAI-GMI, and GAI-DMI discrepancy scores in the WAIS-III/WMS-III standardization sample.

Free volume and mechanical properties of Palacos R bone cement.

The free volume and the mechanical properties of Palacos R bone cement were determined from positron annihilation lifetime spectroscopy (PALS) and from dynamic mechanical thermal analysis (DMA) in the temperature ranges 24-220 degrees C and 30-120 degrees C, respectively. The heating of bone cement caused an appreciable reduction of the free volume, measured as a decrease in the ortho-positronium lifetime tau(3) from 2.04 to 1.91 ns, as well as a clear increase in the storage modulus from 2.3 to 3.0 GPa. The changes in free volume and storage modulus after the heat treatment were interpreted as an effect of elimination of residual monomer from the bone cement. The free volume of the bulk-polymerized phase of bone cement was estimated from a simple difference method, suggesting that the residual monomer was eliminated from the bone cement between 60 and 90 degrees C, thus implying a glass transition temperature of only 60 degrees C for the bulk-polymerized phase. The spherical free volume cavity size estimated from the ortho-positronium lifetime V(tau(3)), and the storage modulus E'(storage) from DMA measurements were found to correlate by a linear relationship throughout the studied temperature range, and the correlation appeared to be independent of the presence of residual monomer.

One Size Still Does Not Fit All in Specific Learning Disability Assessment Across Ethnic Groups

The use of IQ scores and discrepancy formulas for identifying specific learning disabilities (SLD) has been widely discredited by prominent researchers for more than a decade. Nevertheless, the overwhelming majority of state policies still specify the use of discrepancy formulas, including the simple difference method, which is psychometrically inferior to regression-based methods. This study compares the use of a minimum IQ cutoff score and a simple difference method versus a regression-based method for identifying SLD in a sample of African American and European American full-time college students (N = 117). Replicating the findings from previous studies using typically achieving children, typically achieving adults, and school-age children with SLD, this study adds to the chorus of voices criticizing the use of outdated assessment practices that can have deleterious effects for individuals with SLD. The implications for legislative policy are discussed in the context of the historical overrepresentation of African Americans in all special education categories except SLD and the increased access to higher education that students with SLD have gained during the past decade.

Using Simple and Relative Difference to Interpret Changes in Health-Related Quality-of-Life Scores for Salmeterol, Ipratropium, and Placebo

OBJECTIVE: To illustrate how simple difference and relative difference methods can be used to interpret health-related quality-of-life (HRQL) benefits from a treatment, using the proportion of patients achieving a meaningful improvement in HRQl. DESIGN: The data used in this analysis were from two identical randomized clinical trials which compared, chronic obstructive pulmonary disease (COPD}- related quality-of-life benefits of salmeterol, ipratropium, and placebo. MAIN OUTCOME MEASURES: Simple and relative difference equations were applied to the proportion of patients who experienced a meaningful improvement in COPD-related quality of life. RESULTS: Simple difference showed that for 100 patients receiving placebo, an additional 14 (95% C15, 23) would have a meaningful HRQL improvement if given salmeterol, while an additional a (95% CI-1, 17) would have a meaningful improvement if given ipratropium. Using relative difference, for every 100 subjects who fail to respond to placebo, 21 (95% Cia, 31) would...

Changes in Ability and Achievement Scores Over Time: Implications for Children Classified as Learning Disabled

This study examined the effects of WISC-III IQ changes on the IQ-achievement discrepancy required for special education eligibility in the area of Specific Learning Disabled. Within a sample of 224 students with learning disabilities, WISG-III scores were significantly lower when compared to WISC-R scores. No significant changes occurred in achievement scores as measured by the Woodcock-Johnson Revised and the Wechsler Individual Achievement Test. As a result, fewer children retested with the WISC-III qualified for LD services. This drop in eligibility rates was evidenced by both the simple difference and regression methods. The possibility that a significant number of students no longer qualify for LD services should raise concern among psychologists and educators alike. In response to these results, emphasis should be placed upon consultation and pre-assessment intervention designed to serve those students who may no longer qualify for services.