31 research outputs found

    Estimating the shadow economy in Jordan: causes, consequences, and policy implications

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    2011 Fall.Includes bibliographical references.Economists have been paying increasing attention to the study of the shadow economy in many developed and developing countries in recent years. This attention is due to the consequences and the policy implications related to the shadow economy. Due to the unobserved and hidden nature of the shadow economy, it is difficult to get accurate estimates of its size. However, there are some techniques that have been used by economists to indirectly estimate the size of the shadow economy. This dissertation estimates the annual size of the shadow economy in Jordan during the period 1976-2010 using two methodologies: the currency approach and the multiple indicators multiple causes (MIMIC) approach. It also analyzes the economic consequences and the policy implications of the shadow economy, estimating the amount of tax evasion in Jordan during the aforementioned time period. This is the first study that differentiates the effect of taxes on imports (custom duties) on the shadow economy from the effect of other taxes (income and sales taxes). It hypothesizes, unlike other studies, that taxes on imports negatively affect the size of the shadow economy. The currency approach results are consistent with this hypothesis. This study is also the first one to take into consideration religious factors as one of the determinants of the demand for money in circulation which is used in the currency approach to estimating the shadow economy. It is hypothesizes that the number of Islamic banks in Jordan negatively affects the demand for money in circulation. The coefficient of this variable has a negative sign, which is consistent with this hypothesis; however, this variable is insignificant at the 10 percent level. The other determinants of the demand for money in circulation in Jordan are: the effective tax rate on sales, the effective income tax rate, the effective tax rate on imports, the weighted average of interest rates on savings, and a dummy variable for the depreciation of the Jordanian dinar in 1988. According to the MIMIC approach, the causal variables for the shadow economy in Jordan are found to be: the total effective tax rate (tax revenues/GDP), the unemployment rate, the extent of government regulation (government intervention in the economy), and depreciation of the Jordanian dinar in 1988. The growth rate of real GDP and the growth rate of real private consumption are found to be indicators of the shadow economy in Jordan. The MIMIC approach results are consistent with previous studies that have found taxes and regulations to be the main causes of the shadow economy. The results also support the hypothesis that the depreciation of the Jordanian dinar in 1988 has a positive effect on the shadow economy in Jordan. The unemployment rate is found to have a negative effect on the shadow economy in Jordan. This indicates that the income effect of unemployment is greater than the substitution effect. In this dissertation, the main consequences and the policy implications of the shadow economy are analyzed. Tax evasion in Jordan is estimated for the period of study based on the results of the currency demand and the MIMIC approaches. It has been shown that the shadow economy has a distorting effect on the accuracy of a country's national accounts statistics. In addition, some policy recommendations are presented to reduce the distorting impact of the shadow economy. Taking into consideration the existence of the shadow economy when conducting the economic policy will increase the efficiency of this policy. There is a need for further research into the impact of the shadow economy on some economic policy issues in Jordan

    Controlling stress state of a hoisting shaft frame in the context of specific freezing process

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    Purpose is to obtain regularities of a stress state of such multilayer system as neighbourhood rock mass – frozen soil – hoisting shaft frame in the process of numerical analysis to control a frame state with the selection of efficient parameters; thickness depending upon a specific frozen process specifically. Methods. Numerical analysis on the basis of a finite-element method has been implemented relying upon Pro Complex Structure CAD for Windows (SCAD) which made it possible to obtain stress state of a hoisting shaft frame and its interaction with ice-soil blocking as well as with neighbourhood rock mass soil. Findings. Hoisting shaft model has been developed. The model is based upon actual geometry and results of laboratory studies. Three blocking types (i.e. reinforced-concrete blocks, gray cast-iron tubbings, and modified gray cast-iron tubbings) and two soil types (i.e. sand and clayish soil at +8°С temperature) in terms of different freezing temperatures (i.e. (–2, –6 and –10°С) were analyzed numerically with the use of the SCAD. Results of the research have helped identify dependences concerning formation of a stress state of the multilayer neighbourhood rock mass – frozen soil – hoisting shaft frame system while varying properties of the listed types of a frame, neighbourhood rock mass, and ice-soil blocking. Regularities of the stressed state components deepening upon the frozen soil elasticity modulus, corresponding to its certain temperature, and elasticity modulus of a hoisting shaft frame have been obtained. The regularities connect changes in the stress of a hoisting shaft blocking in the context of specific freezing process. Originality. The obtained dependences of the stressed state of a hoisting shaft frame on the soil elasticity modulus and the material are composite spatial surfaces reflecting representatively the stressed state of such multilayer systems as neighbourhood rock mass – frozen soil – hoisting shaft frame. Practical implications. The regularities of the stressed state, determined for such multilayer systems as neighbourhood rock mass – frozen soil – hoisting shaft frame, make it possible to control stress components selecting rational geometry of a frame and its material or temperature cycle to freeze soils while applying the specific method.Мета. Отримання в ході чисельного аналізу закономірностей зміни напруженого стану багатошарової системи “ґрунт оточуючого масиву – заморожений ґрунт – оправа шахтного стовбуру” для управління напруженим станом оправи із підбором ефективних параметрів (наприклад, товщини) в залежності від параметрів спеціального способу заморожування. Методика. Застосовано чисельний аналіз на основі методу скінченних елементів, реалізований на базі професійного комплексу Structure CAD for Windows (SCAD), що дозволив отримати напружений стан оправи шахтного стовбуру із його взаємодією із льодоґрунтовим огородженням та ґрунтом оточуючого масиву. Результати. Створено модель шахтного стовбура, що побудована на основі реальних геометричних розмірів і результатів лабораторних досліджень. В ході чисельного аналізу із застосуванням SCAD досліджено три типи оправи (залізобетонні блоки, тюбінги з сірого чавуну та тюбінги з модифікованого сірого чавуну), два типи ґрунтів (пісок та суглинок при температурі +8°С) при різних температурах заморожування (–2, –6 і –10°С). Результати досліджень дозволили відшукати залежності формування напруженого стану багатошарової системи “ґрунт оточуючого масиву – заморожений ґрунт – оправа шахтного стовбуру” при варіації властивостей вказаних типів оправи, ґрунту оточуючого масиву та льодоґрунтового огородження. Отримано закономірності компонент напруженого стану від модуля пружності замороженого ґрунту, що відповідає певній його температурі, та модуля пружності оправи шахтного стовбуру. Дані закономірності пов’язують зміну напружень оправи шахтного стовбуру при спеціальному способі заморожування. Наукова новизна. Отримані залежності компонент напруженого стану оправи шахтного стовбуру від модулю пружності ґрунту та матеріалу є складними просторовими поверхнями, що репрезентативно відображають напружений стан багатошарової системи “ґрунт оточуючого масиву – заморожений ґрунт – оправа шахтного стовбуру”. Практична значимість. Закономірності напруженого стану, визначені для багатошарової системи “ґрунт оточуючого масиву – заморожений ґрунт – оправа шахтного стовбуру”, дозволяють управляти компонентами напружень, підбираючи раціональні геометричних параметри та матеріал оправи, або температуру циклу заморожування ґрунтів при застосуванні цього спеціального способу.Цель. Получение в ходе численного анализа закономерностей изменения напряженного состояния многослойной системы “ґрунт окружающего массива – замороженный грунт – оправа шахтного ствола” для управления напряженным состоянием оправы с подбором эффективных параметров (например, толщины) в зависимости от параметров специального способа замораживания. Методика. Применен численный анализ на основе метода конечных элементов, реализованный на базе про-профессионального комплекса Structure CAD for Windows (SCAD), позволивший получить напряженное состояние оправы шахтного ствола с его взаимодействием с льодоґрунтовым ограждением и грунтом окружающего массива. Результаты. Создана модель шахтного ствола, построенная на основе реальных геометрических размеров и результатов лабораторных исследований. В ходе численного анализа с применением SCAD исследованы три типа оправы (железобетонные блоки, тюбинги из серого чугуна и тюбинги из модифицированного серого чугуна), два типа грунтов (песок и суглинок при температуре +8°С) при различных температурах замораживания (–2, –6 и –10°С). Результаты исследований позволили отыскать зависимости формирования напряженного состояния многослойной системы “грунт окружающего массива – замороженный грунт – оправа шахтного ствола” при вариации свойств указанных типов оправы, грунта окружающей массива и льодоґрунтового ограждения. Получены закономерности компонент напряженного состояния от модуля упругости замороженного грунта, что соответствует определенной его температуре, и модуля упругости оправы шахтного ствола. Данные закономерности связывают изменение напряжений оправы шахтного ствола при специальном способе замораживания. Научная новизна. Полученные зависимости компонент напряженного состояния оправы шахтного ствола от модуля упругости грунта и материала являются сложными пространственными поверхностями, репрезентативно отражающие напряженное состояние многослойной системы “грунт окружающей массива – замороженный грунт – оправа шахтного ствола”. Практическая значимость. Закономерности напряженного состояния, определенные для многослойной системы “грунт окружающей массива – замороженный грунт – оправа шахтного ствола”, позволяют управлять компонентами напряжений, подбирая рациональные геометрические параметры и материал оправы, или температуру цикла замораживания грунтов при применении этого специального способа.The results of the study were obtained in the process of implementing the state-financed research Analytical regularities of a stress-strain state of frame of hoisting shafts while specific operation performing (official registration No. 0117U006810). The authors express thanks to S.M. Likhman, Chief Engineer of Kyivmetrobud PJSC, and M.V. Bilous, Candidate of Science and Director of a Ukrheodezmark being a subsidiary company of Kyivmetrobud PJSC for their counseling as for the specific method of soil freezing and selection of rational designs of a hoisting shaft

    Measuring institutions’ adoption of artificial intelligence applications in online learning environments: integrating the innovation diffusion theory with technology adoption rate

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    Artificial intelligence applications (AIA) increase innovative interaction, allowing for a more interactive environment in governmental institutions. Artificial intelligence is user-friendly and embraces an effective number of features among the different services it offers. This study aims to investigate users’ experiences with AIA for governmental purposes in the Gulf area. The conceptual model comprises the adoption properties (namely trialability, observability, compatibility, and complexity), relative advantage, ease of doing business, and technology export. The novelty of the paper lies in its conceptual model that correlates with both personal characteristics and technology-based features. The results show that the variables of diffusion theory have a positive impact on the two variables of ease of doing business and technology export. The practical implications of the current study are significant. We urge the concerned authorities in the governmental sector to understand the significance of each factor and encourage them to make plans, according to the order of significance of the factors. The managerial implications provide insights into the implementation of AIA in governmental systems to enhance the development of the services they offer and to facilitate their use by all users

    Examining the impact of artificial intelligence and social and computer anxiety in e-learning settings: students’ perceptions at the university level

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    The learning environment usually raises various types of anxiety based on the student’s abilities to use technology and their abilities to overcome the negative feelings of an individual being watched all the time and criticized. Hence, learners still feel anxious while using computers and socializing in an e-learning environment. Learners who are faced with computer and AI tools are confused and frustrated. The uneasiness stems from anxiety or uneasiness, which is highly evident in daily interaction with computers and artificial intelligence tools or devices in e-learning contexts. The uneasiness stems from anxiety or uneasiness, which is highly evident in the daily interaction with computers and artificial intelligence tools or devices in e-learning contexts. To investigate this phenomenon empirically, a questionnaire was distributed among a group of undergraduate students who are studying different majors. This study aims to investigate the role of social anxiety and computer anxiety in an e-learning environment at the university level. Universities in the Gulf area are among those implementing e-learning systems. In spite of this, recent studies have shown that most students at Gulf universities are still resistant to using online systems; hence, it is necessary to determine the type of anxiety that creates such resistance and their relationship with other external variables such as motivation, satisfaction and self-efficacy. Students would be more likely to use e-learning tools and participate more effectively in their courses using the accessible electronic channels when the degree of anxiety is low. In this study, we have proposed a theoretical framework to investigate the role of social anxiety and computer anxiety in e-learning environments in the Gulf region. We examined how different variables such as satisfaction, motivation and self-efficacy can negatively or positively affect these two types of anxiety

    Ultraestructura de la retina externa de Aphanius sirhani (Villwock, Scholl & Krupp, 1983) (Cyprinodontidae, Teleostei)

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    The ultrastructure of the outer retina in the endangered killifish, Aphanius sirhani was studied. The retina shows all eight layers and two membranes typical of vertebrates. The retinal pigment epithelium (RPE) consists of a single layer of closely packed, polygonal, low columnar cells. These cells have large, vesicular nuclei, well developed smooth endoplasmic reticulum, and well developed mitochondria. Phagosomes, lipid droplets and myeloid bodies are also evident. The cells bear numerous apical processes that, in light-adapted fish, interdigitate with the photoreceptor outer segments. The retina is of the duplex type, i.e. contains rods and cones. A variety of cones have been recorded in the present species. These include short, intermediate and long single cones, double and triangular, triple cones. Rod spherules each with a single synaptic ribbon and cone pedicles, each with several synaptic ribbons have been recorded in the outer plexiform layer

    Prediction of the stress-strain state of circular workings in a layered massif by scaling

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    The scientific and technical task for determining the stress-strain state of mine workings is complicated by the presence of a layered massif. This task assumes particular importance in the case of circular tunneling. During its operation, it is important to predict the change of the stressstrain state for the massif or to carry out the prompt determination in the change of stresses and displacements for the unsupported working. The solution of this geomechanical task allows performing geometrical matching of the working, ensuring its strength and stability in the layered massif. A numerical finite element method based on StructureCAD (SCAD) software package was used to solve it. Four geomechanical systems were calculated: “unsupported working – layered massif”. Owing to the obtained results, graphs of stresses and displacements were constructed, which allow to determine these parameters for workings with different geometric parameters and X-parameter characterizing the ratio of the elasticity modulus of the matrix and the layer. Obtained regularities of change of stresses and displacements for the unsupported working when zooming made it possible to introduce scaling-parameters, which are a dimensionless ratio of the radii for a real system and a system with a unit diameter

    Regularities of stress state of unsupported working occurring in a layered massif

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    The paper defines the regularities of stress state of unsupported working occurring in a layered massif. The relevance of the performed research is substantiated by the importance of determining the stresses of the contour of unsupported working when the elastic modulus of the matrix and the layer is varied. Since the application of analytic methods for this case is complex, we used a numerical finite element method, implemented in the SCAD. We developed a finite-element model of the above working, where the elastic moduli of the matrix and the layer varied greatly, while its position was unchanged (the layer laying in the middle of the working). The results of the numerical analysis allowed us to build the regularities of three stress components. In order to normalize cases of elastic modulus variation, a dimensionless χ -parameter is introduced which characterizes the relation between the elastic modulus of the matrix and the layer. The obtained regularities of the stress state of the χ-parameter have a functional character and allow to determine the stresses on the contour of the unsupportedworking, depending on the relation between the elastic moduli of the matrix and the layer for all possible spectrum of these parameters

    THE STUDY OF THE INFLUENCE OF THE DEFORMATION CHARACTERISTICS OF THE LAYER OF REINFORCEMENT ON VAT RAILWAY EMBANKMENT AT THE ENTRANCE TO THE BRIDGE CROSSING

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    In the article the results of influence of deformation descriptions of strengthening layer on the tensed-anddeformed state of railway embankment are presented. The comparative FEM analysis has allowed finding out that such type of strengthening has no positive effect

    Nonuniform stress state of a hoisting shaft lining as a result of disturbance of the ground freezing technology

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    The paper deal with the defining stress state of a hoisting shaft lining, lying in the sandy loam, when performing and disturbing the ground freezing technology. The relevance of the performed research lies in the fact that at nonuniform freezing or defrosting, nonuniform stress state is formed, which causes a significant over-stresses of the lining. To research the nonuniform stress state, a spatial finite element model of a hoisting shaft was developed, in which the case of nonuniform ground freezing was simulated. The calculation by the finite-element technique was carried out on the basis of the computational professional complex Structure CAD for Windows. In the course of the analysis, the values of stress state for linings made of reinforced-concrete blocks, B30 concrete, gray and modified cast-iron tubbings. A comparison of the components of stress state for sandy loam at a temperature of -2 °C (freezing), nonuniform freezing and at a temperature of + 8 °C (defrosting) was carried out. It was found that for the proposed geotechnical conditions in the form of soft, water-saturated sandy loam, it is recommended to use a lining made of gray and modified cast-iron tubbings
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