Terms Of Arithmetic Means Research Articles

Factors Affecting Indoor Radon Levels in Buildings Located in a Karst Area: A Statistical Analysis

In this paper, the averages annual radon concentrations in buildings placed in a karst area are analyzed in order to understand which factors may affect the occurrence of high levels of radon indoor. Statistical analysis on the radon dataset is performed using analytical factors described by two or three levels according to the characteristic of the measured buildings. The factors that determine higher radon levels in terms of arithmetic mean (AM) at ground floor (GF) are mainly the presence of sedimentary calcareous rock (SCR) in walls and the direct attack or crawl space as type of foundation. At first floors (FF), the presence of walls of only SCR showed radon levels higher (in terms of AM) than the one found for walls of mixed typology. These outcomes suggest that in karstic area buildings with SCR as the main construction material and direct attack or crawl space as the type of foundation, can be considered as radon-prone buildings. Moreover, this study confirms the need to measure radon levels not only at below ground floor and at GF, but also at FF and above for buildings in karst areas with construction materials including SCR blocks.

Virtual Commerce Management Using Design Thinking Process to Promote Digital Entrepreneurship for Education Studies

The objectives of this research were to (1) develop virtual commerce using the design thinking process to promote modern entrepreneurship, (2) carry out a suitability assessment of this process, and (3) evaluate digital entrepreneurship competency (DEC). The research process was therefore divided into 3 phases in accordance with these aims. The evaluation of the developed model was carried out by 7 experts in related fields, and the implementation of the model was carried using a sample of 50 users. Evaluation was measured on a Likert scale and implementation on a scoring rubric from the data in terms of arithmetic means and standard deviations. The results showed that: (1) the DEC model consists of 6 dimensions: 1. design thinking process, 2. entrepreneurship skills, 3. digital platform, 4. eCommerce Platform, 5. 7Cs, 6. Digital User Citizenship; (2) the DEC model was evaluated as being highly appropriate (X=4.80, S.D.=0.21) and (3) the DEC was rated as being at the highest appropriate level.

Radon levels in dwellings and workplaces: a comparison with data from some European countries

Background: According to 2013 European Basic Safety Standards (EU BSS), legal and administrative consequences of having an area declared as radon priority area (RPA) concern workplaces (WP) and public buildings, as well as dwellings (DW). However, RPAs in many cases are defined as higher levels of indoor radon in DW. The reason is that most data are available for DW. So far, indoor radon data for WP (except for schools) and public buildings are scarce.
 Objective: The objective of this study was to compare indoor radon levels in DW and WP in a given area and to evaluate whether they have different distributions and different average levels.
 Design: Austria, Finland, Germany, and Italy provided indoor radon data on DW and WP.
 Data related to WP were aggregated in the same grid, as already done for data on DW, to update the European Indoor Radon Map. Based on 10 km × 10 km grid cells, the same statistics are computed for both datasets. Thus, two structurally equal datasets for each country were generated to be statistically compared.
 Results and conclusions: Generally, there are numerous indoor radon data on DW than data on WP. Statistical analysis suggests that in all the countries, indoor radon levels – in terms of arithmetic mean (AM) of the natural logarithm-transformed data – in WP and DW are statistically different (P < 0.05), as well as from those referring to schools. The difference in distributions is neither attributable to the effect of geology nor to the effect of different sample sizes.
 The correlation between aggregated data is positive in the sense that if the mean (over grid cells) radon concentration increases in DW, it increases in WP as well. Compared with DW, in all countries indoor radon levels in WP seem to be statistically different, but the results are not enough to draw final conclusions: on-purpose designed surveys could be a useful tool to better understand this phenomenon.

Radon Spatial Variations in University’s Buildings Located in an Italian Karst Region

In the framework of a collaboration between INAIL and University of Salento, an indoor radon survey in 54 buildings belonging to the UniSalento University (Southeast Italy) was carried out. The monitored buildings differ by type, construction period, materials, etc., and are located in an area with a morphology characterized mainly by marls, calcareous marls, and calcarenites (karst area). The sample of the survey includes 963 rooms at different floors: it consists in rooms mainly located at ground floor (67%), first floor (12%), and below ground (12%). SSNTD passive dosimeters measured the average radon activity concentration for two consecutive semesters (spring/summer and autumn/winter) from which annual radon averages were estimated for each room. The spatial variability within buildings was investigated in terms of variation between floors and among rooms at the same floor. Data analysis provides evidence that the distributions (in terms of arithmetic mean, standard deviation, median, and geometric mean) of indoor radon annual averages at ground floor and at first floor within building are very similar. This highlights that the karstic characteristics of soil and building materials affect radon levels not only below ground and at ground floor, but also at first floor. Moreover, to evaluate the spatial variability of radon among buildings or floors, the analysis of the distribution of coefficient of variation (CV) was carried out: the results show a low spatial variability with median and average values of CVs ≤ 30% both for the whole building and at different floor levels.

A validity and reliability study of the Basic STEM Skill Levels Perception Scale

The aim of this study is to develop a perception scale related to the possible basic skills that can be gained through STEM. Participants of this study were 723 university students. In this study, descriptive survey study was conducted. To identify validity of the scale exploratory factor analysis, cumulative item factor, corrected correlations and item discrimination were calculated. For reliability internal consistency and stability level were calculated. Collected data were analyzed in terms of arithmetic mean, standard deviation, t and ANOVA. The scale is a 7-point likert-type scale which consists of 43 items under 3 factors. Data analysis results showed that this scale is valid and reliable for measuring students’ STEM skills according to their perceptions.

Ant inspired Monte Carlo algorithm for minimum feedback arc set

It is well known that Minimum Feedback Arc Set is in a general case NP-complete. There are different kinds of exact, heuristic and approximation algorithms for solving this problem, but currently there is only one published Monte Carlo algorithm which solves Minimum Feedback Arc Set in polynomial time with arbitrary probability. To further advance the state of the art we have devised new and improved ant inspired Monte Carlo algorithm which on average has 20% faster empirical running time. Due to a learning mechanism the new algorithm also achieved 511% faster convergence in terms of median and 158% improvement in terms of arithmetic mean. This has been done while at the same time maintaining the ability of the algorithm to find optimal solution with arbitrary probability. In addition, the new and improved ant inspired algorithm has substantially improved convergence consistency. A tighter probability bound has also been calculated for the Monte Carlo algorithm. The aforementioned contributions have their significance in a design and implementation of expert and intelligent system. Considering a wide presence of MFAS in a variety of areas the obtained results are significant in other applications as well.

English

In this study, 200 volunteer students who were in Faculty of Education printed free essay compositions and the compositions were evaluated by descriptive statistics and content analysis. Content analysis is to interpret similar data within specific contexts and themes. The students were free to choose their own writing topic. The reason for this is the possibility that the person writing in freelance writing is feeling freer and thus able to collect more data. Thus, written expression errors will be examined in more detail. The data have been examined and themed. In this process, collected data were evaluated according to written expression evaluation scale. The results of this study indicated that 200 data points collected from education faculty students regarding written expression skills were found between acceptable “DC” in terms of arithmetic mean. Research is important in terms of revealing the mistakes that are often found in written expressions of teacher candidates. This research is also important for lecturers in terms of assessing the participant teacher candidates’ attitudes towards writing. According to the findings of this research, it is expected that the mistakes of teacher candidates’ in their written expressions are made clear, and that contributions of the recommendations and the studies related to the field are expected to be provided. It is expected that the comparison of the study with the previous studies reveal the changes and developments in the historical process related to the subject. Key words: Language skills, Turkish education, teacher candidates, writing skills.

The effect of material selection and manufacturing process on the surface finish of carbon fibre composites

Using a design of experiment (DOE) approach, this work investigated the surface finish of as-moulded and painted carbon fibre composite laminates manufactured by two alternative methods, autoclave and a rapid curing process—Quickstep™. The effect of two fibre architectures on the surface finish of unidirectional and 2 × 2 twill laminates combined with a surfacing film was studied using surface profilometry and wave-scan distinctness of image (DOI) techniques. Investigation of the as-moulded surface finish showed that the autoclave cured laminates had lower surface roughness than the Quickstep laminates in terms of arithmetic mean ( Ra), maximum peak to valley height ( Rt), skewness ( Rsk) and kurtosis ( Rku). Interaction effects showed that the surfacing film reduced the Rsk and Rku when combined with the unidirectional fibre architecture but increased with the twill material. The autoclave manufactured panels combined with the unidirectional material improved the painted surface finish as identified by the DOI and long-term waviness main effect plots. Surface roughness results could not detect the influence of manufacturing and material variables on the painted surface finish. The painting process caused the microsurface defects to be concealed, resulting in defects of larger structure sizes to remain as observed using the wave-scan DOI technique.

Effect of diamond burs on process and damage involving in vitro dental resurfacing of a restorative porcelain

This work reports on the effect of diamond burs with coarse, medium and fine grit sizes and nickel or chromium coatings on in vitro dental resurfacing of a restorative porcelain. Process parameters such as tangential and normal forces, surface roughness, surface damage and morphology were studied as a function of removal rate using the different burs. At the lower removal rate, the differences for both the tangential and the normal forces were not significant among the coarse, medium and fine burs. However, when the porcelain was removed at the higher removal rate, both the tangential and the normal forces were markedly higher using the fine bur than those using the medium and coarse burs. Surface roughness values in terms of arithmetic mean and maximum roughness decreased significantly with a decrease in diamond grit size. The scale of surface damage in the form of brittle fracture decreased, and more transitions from brittle removal to ductile flow were observed when using finer grit diamond burs. In a comparison of the diamond bur topographies before and after dental finishing, it was found that minimal wear occurred on the nickel-coated coarse diamond bur, while minor abrasive wear occurred on the nickel-coated medium and chromium-coated fine burs.

Traces, ideals, and arithmetic means.

This article grew out of recent work of Dykema, Figiel, Weiss, and Wodzicki (Commutator structure of operator ideals) which inter alia characterizes commutator ideals in terms of arithmetic means. In this paper we study ideals that are arithmetically mean (am) stable, am-closed, am-open, soft-edged and soft-complemented. We show that many of the ideals in the literature possess such properties. We apply these notions to prove that for all the ideals considered, the linear codimension of their commutator space (the "number of traces on the ideal") is either 0, 1, or infinity. We identify the largest ideal which supports a unique nonsingular trace as the intersection of certain Lorentz ideals. An application to elementary operators is given. We study properties of arithmetic mean operations on ideals, e.g., we prove that the am-closure of a sum of ideals is the sum of their am-closures. We obtain cancellation properties for arithmetic means: for principal ideals, a necessary and sufficient condition for first order cancellations is the regularity of the generator; for second order cancellations, sufficient conditions are that the generator satisfies the exponential Delta(2)-condition or is regular. We construct an example where second order cancellation fails, thus settling an open question. We also consider cancellation properties for inclusions. And we find and use lattice properties of ideals associated with the existence of "gaps."