INVESTIGATION OF MEASUREMENT PRECISION OF LATENT VARIABLES DEPENDING ON THE NOISE TEST RESULTS

Measurement precision is an important aspect of experimental studies because it affects the effectiveness of decisions. The precision of measurements is influenced by many factors, including the quality of the original data or how the data was obtained. When measuring a latent variable, one of these factors is the precision of the indicators. For example, there may be situations in which, for various reasons, the subject gave the wrong answer instead of the correct answer and vice versa. This fully applies to conducting surveys. In general, we are talking about the noise of the original data. The aim of the work is to analyze the precision of measurement of the latent variable depending on the degree of noise of the original data. The results of the simulation experiment are used as initial data, which allows to simulate the necessary experimental situations. The analysis is conducted within the framework of the theory of latent variables, which allows to obtain estimates of the latent variable on a linear scale. The measurement precision of the latent variable is determined on the basis of absolute error. The noise level of the original data varies from 0 to 0.10%. It is shown that even minor noise of the original data significantly reduces the precision of the measurement of the latent variable.

CHARACTERISTIC VALUE OF THE RANDOM FIRE LOAD DENSITY, Probability-based specification depending on the way how the building compartment is used

The algorithm that allows to specify the characteristic value of the random fire load density, depending on the way how the considered building compartment is used, is presented and discussed in detail. The proposed computational procedure is based on a probabilistic approach, the alternative in relation to the traditional methodology according to which the results obtained from the inventory of such a compartment are a basis for the evaluation. It is assumed that the sought value is estimated as the upper quantile of a Gumbel probability distribution which is set at an appropriate level of the probability of its up-crossing. The formal model described in the paper is referred to the two selected and qualitatively different design techniques which are used in practice. The first one is based on the recommendations contained in the Eurocode EN 1991-1-2, whereas the second - on the rules specified in the standard NFPA 557

ANALYSIS OF THE QUESTIONNAIRE FOR ASSESSING THE LEADERSHIP QUALITIES OF STUDENTS

The quality of the questionnaire as a measuring tool largely determines the relevance of the results. The aim of the work is to analyze the quality of the questionnaire as a measuring tool used to evaluate the latent variable "leadership qualities of students". The study was conducted within the framework of the theory of measurement of latent variables, which has important advantages. First of all, the latent variable is determined operationally, through a set of indicators (questionnaire items), the more indicators, the higher the accuracy of the latent variable measurement. The latent variable and indicators are measured on the same interval scale in logits. This allows the use of a wide range of statistical procedures for the analysis of measurement results. The analysis of the following aspects of the quality of the questionnaire as a measuring tool: the presence of extreme indicators in the test, the compatibility of a set of indicators, the compliance of the questionnaire to the level of students on the measured latent variable, the uniformity of the distribution of indicators on the interval scale. The indicators that differentiate students with high and low levels of leadership qualities better than others are highlighted. Recommendations on the adjustment of the questionnaire as a measuring tool for assessing the leadership qualities of students are given.

Effect of Instructional Consultation on Academic Achievement in Third Through Fifth Grade

The present study evaluated the effect of Instructional Consultation (Rosenfield, 1995) on the academic achievement of third through fifth grade students. Students whom teachers did (n = 201) and did not (n = 8119) select as the focus of consultation were balanced on their estimated propensity to be selected using logistic regression of observed covariates. Multilevel modeling compared students in the two treatment conditions on teacher assigned grades and standardized measures of reading and math, net of prior achievement. A small, but statistically significant negative effect of the program (d = -.13) was found for standardized measures of math. No significant differences were found on the other outcome measures. Limitations include model misspecification, missing data, and treatment diffusion

Head-associated lymphoid tissue [HALT] of the chicken: characterization of lymphocytes

The head-associated lymphoid tissues (HALT) of the chicken are composed of the Harderian gland and the conjunctiva-associated lymphoid tissue (CALT). Since these lymphoid tissues are potential immunological sites to be exposed to respiratory disease agents and intraocular and aerosol vaccines, lymphocytes of the HALT were studied. Methods employing in vitro and in situ techniques were used to examine the lymphocytes of the HALT. An in vitro lymphoproliferative assay was optimized to measure mitogenic responses of lymphocytes isolated from the spleen, peripheral blood, and Harderian gland. Harderian gland lymphocytes responded to T and B cell mitogens as did the lymphocytes from the spleen and blood. Mitogenic responses of the lymphocytes isolated from CALT could not be measured by the described methodology. An in situ immunocytochemical technique was used to identify lymphocyte subpopulations of the HALT as the chicken aged. The concentration of T cells, particularly T cells expressing pan T cell and T helper cell epitopes, within the Harderian gland increased with age; while the B lymphocyte population remained unchanged. Aggregates of B lymphocytes within the CALT appeared more frequently as the chicken aged and as the germinal centers developed. All T lymphocyte subsets stained within the CALT surrounded the germinal centers and increased in concentration between 1 and 4 weeks of age;Both of these techniques were used to evaluate lymphocytes from the HALTs of chicks intraocularly inoculated with Newcastle disease virus (NDV). Velogenic and lentogenic strains of NDV were used. In the in vitro lymphoproliferation assay, Harderian gland T cells isolated from the NDV inoculated chicks had a significantly higher lymphoproliferative response to in vitro NDV antigen compared with the T cells isolated from phosphate buffered saline control hatch mates. A significant increase in all T lymphocyte subsets was observed in the in situ analysis of the Harderian glands from chicks inoculated with either lentogenic or velogenic NDV when compared with chicks inoculated with phosphate buffered saline solution. No differences in the lymphocyte subsets were observed from the CALT collected from any of the three treatment groups. The results presented could contribute to vaccine program development against respiratory diseases

Thermal energy use in three Swedish greenhouses – the outdoor temperature-dependent variation and the influence of wind speed under no-sunlight conditions

Thermal energy is used in greenhouses for the temperature and humidity control.  In the North of Europe, energy expenditures have a significant share in the total greenhouse production cost.  A study was performed to quantify and analyze the use of thermal energy in three Swedish commercial greenhouses (two with tomatoes and one with ornamental plants), to test the hypothesis that substantial amounts of heat are used at higher outdoor temperatures, and to investigate the influence of the wind speed on the energy use under no-sunlight conditions.  Hourly climate data were registered by means of Priva control systems.  The use of thermal energy was computed based on the readings from the flowmeters and the temperature of the inlet/outlet water to/from the boilers.  In the study, seven different ranges of outdoor temperatures for studying energy use at various outdoor temperatures were considered.  The use of thermal energy in Greenhouse A amounted to 793 MJ/m2 (April-October).  The yearly use of thermal energy in Greenhouse B with tomatoes was 1529 MJ/m2 and in Greenhouse C with ornamental plants 873 MJ/m2.  The results showed a positive relation between the wind speed and the use of thermal energy.  Under no-sunlight conditions, correlation coefficients between the wind speed and the use of thermal energy obtained for the various outdoor temperature ranges being considered were in the range of 0.017 to 0.470.  Calculations suggested that a reduction of the wind speed, e.g. by a fence or trees, by 50% may result in a 4% to 10% decrease of thermal energy use.  In one of the greenhouses (A) the magnitude of thermal energy use at higher outdoor temperatures (15°C to 20°C) was similar to the use in the same greenhouse at outdoor temperatures of 10°C to 15°C.  It was noted that the use of thermal energy is dependent on more factors than the wind speed and the outdoor temperature and that the importance of energy efficient dehumidification should be studied in future work.   Keywords: Thermal energy use; greenhouses; tomatoes; ornamental plants; wind spee

Практика використання інтерактивних мультимедіа інсталяцій у сфері музейної справи

The purpose of the study is to analyze modern interactive multimedia installations that function in the museum environment in the process of working on artistic interactive and educational media projects. The research is devoted to the theoretical and methodological principles of use of interactive multimedia installations in the activities of museum institutions. Methodology. The selection of the actual material was based on the general scientific methods of visualization, analysis and synthesis, comparison and generalization; methods of system analysis, comprehensiveness, objectivity and retrospective were used precisely, when studying innovative systems that function within museum institutions. In the process of presenting the main provisions of the article system-structural and statistical- analytical, comparative and descriptive methods were used. Scientific novelty. For a thorough research of the modern activity of the museum industry through the prism of introduction of interactive installations, the authors have studied the conceptual approaches to hardware and software design of interactive multimedia projects in museums. They have developed their own interactive and educational multimedia project "The Pantheon of Prominent Ukrainians". Conclusions. The factors of using innovative multimedia installations were determined. The importance of information technologies for the development of modern museum expositions wasemphasized.Целью исследования является анализ современных интерактивных мультимедийных инсталляций, функционирующих в музейной среде в процессе работы над художественными интерактивно-образовательным медиа проектами. Исследование посвящено теоретико-методологическим основам использования интерактив-ных мультимедийных инсталляций в деятельности музейных учреждений. Методология исследования. Отбор фактического материала основывался на общенаучных методах визуализации анализа и синтеза, сравнения и обобщения; метод системного анализа, всесторонности, объективности и ретроспективы, были использованы именно при изучении инновационных систем, функционирующих в сфере музейных учреждений. В процессе из-ложения основных положений статьи использовались системно-структурный, статистическо-аналитический, сра-внительный и описательный методы. Научная новизна. Для исследования современной деятельности музейной отрасли сквозь призму введения интерактивных инсталляций были изучены концептуальные подходы к аппарат-но-программному оформления интерактивных мультимедиа проектов в музеях. Разработан собственный интера-ктивно-образовательный мультимедиа проект "Пантеон выдающихся украинцев". Выводы. Определены факторы использования инновационных мультимедийных инсталляций. Подчеркнуто значение информационных тех-нологий для развития современных музейных экспозицийМетою дослідження є аналіз сучасних інтерактивних мультимедійних інсталяцій, що функціонують у музейному середовищі у процесі роботи над художніми інтерактивно-освітніми медіа-проектами. Дослідження присвячено теоретико-методологічним засадам використання інтерактивних мультимедійних інсталяцій в діяльності музейних установ. Методологія дослідження. Добір фактичного матеріалу ґрунтувався на основі загальнонаукових методів візуалізації, аналізу і синтезу, порівняння та узагальнення ; метод системного аналізу, всебічності, об’єктивності та ретроспективи, було використано саме під час вивчення інноваційних систем, що функціонують в середовищі музейних установ. У процесі викладу основних положень статті використовувалися системно-структурний, статистично-аналітичний, порівняльний та описовий методи. Наукова новизна. Для ґрунтовного дослідження сучасної діяльності музейної галузі через призму запровадження інтерактивних інсталяцій були вивчені концептуальні підходи до апаратно-програмного оформлення інтерактивних мультимедіа проектів в музеях. Розроблено власний інтерактивно-освітній мультимедіа проект "Пантеон визначних українців ". Висновки. Визна-чено фактори використання інноваційних мультимедійних інсталяцій. Підкреслено значення інформаційних тех-нологій для розвитку сучасних музейних експозицій

Design value of a headed stud shear resistance in composite steel – concrete beams – probability-based approach to evaluation

[EN] Conventional standard procedure used to determine the design value of a headed stud shear resistance in composite steel-concrete beams is very simple but, in fact, mathematically incorrect, particularly in the case when such connector is automatically welded and when it is working in a solid slab. According to this approach the considered value is specified as a minimum of two separate design values. One of them is related to the resistance of the stud itself while the other is associated with the failure of the surrounding concrete. In the paper presented by the authors a new algorithm which allow to evaluate this value is recommended and discussed in detail. It seems to be more accurate because it is based on the fully probabilistic inference. In such approach a new random variable is introduced, being a minimum of two other, statistically independent, random variables. Analogously as it is in the concept previously mentioned, the first random variable quantifies now the steel stud shear resistance whereas the second one – the resistance of the adjacent concrete. Consequently, the sought design value is determined as a suitable quantile of this new random variable, characterized by log-normal probability distribution. It is shown that the design value of a headed stud shear resistance, calculated in this manner, strongly depends on the variability of strength parameters, relating both to the steel of which the connecting stud is made and to the concrete of the slab. In addition, it is found that in the case when the variability of concrete strength is too high, the safety factor recommended to use in European standards is not able to provide the required safety level, acceptable by the building users. The considerations presented in the article are illustrated by a detailed computational example.Maslak, M.; Domanski, T. (2018). Design value of a headed stud shear resistance in composite steel – concrete beams – probability-based approach to evaluation. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 237-242. https://doi.org/10.4995/ASCCS2018.2018.6950OCS23724

MEASUREMENT AND ANALYSIS OF TEACHERS’ PROFESSIONAL PERFORMANCE

The relevance of the measurement and analysis of teachers’ professional performance is based on the fact that teachers largely determine the quality of education at schools. The measurement of the latent variable "teacher’s professional performance" is done within the framework of the theory of latent variables based on the Rasch model. It was shown that the set of indicators has a high differentiating ability. The results of the measurement of this latent variable are used to compare the quality of professional activities of teachers of mathematics, history, Russian language, and literature as well as primary school teachers. No statistically significant differences were found between the professional performance of teachers of mathematics, history, and primary school teachers. The quality of professional activity of teachers of Russian language and literature is lower. The results of the measurement of teachers’ professional performance were used for comparison of schools. As one would expect, the highest quality of professional performance of teachers is in high schools and lowest in the primary schools; secondary schools occupy an intermediate position. Teachers’ professional performance is defined operationally, using a set of indicators. This set of indicators can be adjusted to clarify the content of the latent variable "teacher’s professional performance"

Interactive shear resistance of corrugated web in steel beam exposed to fire

The design approach to shear buckling resistance evaluation for corrugated web being a part of a steel beam exposed to fire is presented and discussed in detail. It is based on the experimentally confirmed interaction between the local and global elastic instability failure modes as well as on the possible yielding of the whole web cross – section during fire. Conclusively, the new formulae, adequate for specification of the suitable shear buckling coefficients depend not only on the web slenderness but also on the temperature of structural steel. The methodology proposed by the authors can be added to the current European standard recommendations given in EN 1993-1-2 as a well-justified design algorithm helpful in reliable evaluation of safety level for steel beams with slender corrugated webs subject to fire exposure. It seems to be highly desirable, because at present there are no detailed instructions in this field