bluuebunny/crossref_metadata_2025 huggingface dataset:
Debonds and water-filled defects detection in honeycomb sandwich composites based on pulse infrared thermography ndt technique
Authors: Liu Guozeng , Gao Weicheng , Liu Wei , Zou Xionghui , Xu Jianxun , Liu Tao
Published: April 2024

Honeycomb Sandwich Composites (HSCs) have been extensively used in aerospace, automotive and shipbuilding industries due to their light weight, high temperature resistance, high strength and fatigue resistance. In this study, the infrared thermography was used to detect debonds and water-filled defects in HSCs specimens under pulsed thermal stimulation. To improve the efficiency of defects detection, dynamic thermal tomography (DTT), principal component analysis (PCA) and total harmonic distortion (THD) techniques were applied to the raw infrared image sequences. The results show that, in the inspection of HSCs, the defect identification results can be improved by using the image processing techniques mentioned above, while the signal-to-noise ratio (SNR) can be significantly improved by means of the THD technique. It is confirmed that debonds and water-filled defects in the HSCs can reliably be detected and identified by using the technique of pulse infrared thermography nondestructive testing.
Using a magnetic flux leakage method to estimate railway track bolted joint gaps
Authors: Antipov A. G , Markov A. A , Maksimova E. A
Published: April 2024

The periodic estimation of the rail joint gap values allows evaluating the reliability of the continuous welded railway track and preventing its temperature deformations. The purpose of this study is to search for a simple and reliable way to evaluate the rail joint gap, which allows you to determine the desired values during high-speed inspection in automatic mode in a wide range of temperatures. A brief overview of existing techniques for evaluating rail joint gaps based on different physical principles is given. In the proposed technique, a magnetic flux leakage (MFL) method with the placement of electromagnets on the wheel axes of a car bogie is used. Such magnetization systems are applied recently on flaw-detector cars and provide a stable magnetic flux in the tested rails. Using a three-dimensional model of the rail segment with a bolt joint, we studied the characteristics of the magnetic flux leakage fields when changing the size of the rail gap in the entire practical range. The characteristics are selected that are most sensitive to a change in the gap and by which its value can be determined. With small values of the gaps the amplitude of the magnetic sensor signal is proposed as a main informative parameter, and with large gaps the estimation based on the distance between the signal extremums is more preferred. The results of computer modeling of the influence of the joint gap on the parameters of the magnetic signal qualitatively coincide with the results of field measurements made at inspection speeds up to 60 km/h.
Analysis of the destruction processes of carbon fiber samples using acoustic emission and tensometry
Authors: Stepanova L. N , Chernova V. V , Kabanov S. I
Published: April 2024

With samples made of carbon fiber, static tests were carried out to failure. Defects were controlled using acoustic emission and tensometry. Four wire strain gauges were glued to each sample in the area of the hole, and four piezoelectric gauges were installed along its edges, forming the working zone of control. Registration of signals associated with the destruction of the composite material of the samples, and their location was carried out by the acoustic emission system. In the process of testing, the tensometric system recorded loads and deformations, at which the process of destruction of carbon plastics began. The types of destruction were determined during the analysis of micro-glyphs, which were made from location zones. The main informative parameters (amplitude, dominant frequency, MARSE, structural coefficient) of acoustic emission signals were associated with the type of failure of carbon fiber reinforced plastics.
Estimation of the segregation in a high carbon cast steel by thermoelectric power means
Authors: Hernandez L. , Carreon H. , Bedolla A.
Published: April 2024

This research study proposes the hot-cold tip thermoelectric power (TEP) method to estimate alloying elements segregation and the microstructure variation of high carbon steel cast in a mold. Optical Emission Spectrometry (OES) showed a higher concentration of carbon, nickel, chromium and aluminum at the ingot center. That elemental saturation produced an increase in perlite content as well as hardness. The non-destructive technique of thermoelectric power was applied varying the hot tip temperature (40 oC, 50 oC, 60 oC, 70 oC), where higher temperature values showed to be more sensitive to segregation and microstructural changes. The statistical analysis showed that the thermoelectric power technique is more sensitive to detect the nickel and chromium concentration changes.
Efficiency of using different types of infrared imagers in active thermal nondestructive testing of delaminations in non-metals
Authors: Kladov D. Yu , Chulkov A. O , Vavilov V. P , Stasevskiy V. I , Yurkina V. A
Published: April 2024

Six types of infrared imagers characterized by different technical performance (arrays from 160×120 to 640×512 and temperature sensitivity from 25 до 110 mK) and cost were used in active thermal nondestructive testing of delaminations with size from от 5×5 to 45×45 mm located at the depth of 3,1 mm in a reference sample made of polymethylmetacrilat. The efficiency of TNDT was evaluated by 9 thermographers to demonstrate that reasonable inspection results can be achieved by using IR imagers and modules of an economic cost segment.
Methodological issues of increasing the reliability of ultrasonic testing of railways
Authors: Bobrov A. L , Goncharov K. I
Published: April 2024

The paper considers the factor of temperature influence on the sensitivity of ultrasonic testing and the detection of cracks in rails. Research have shown that the sensitivity of control and the detectability of defects significantly depend on the temperature of the test object and the transducer. The results of the experiments should be taken into account in order to increase the reliability of detection of real fatigue cracks.
Some aspects of optical monitoring of pile foundations under the conditions of the far north
Authors: Fedotov M. Yu
Published: April 2024

This article describes the practical aspects of creating an effective fiber-optic system of monitoring the load-bearing constructions of engineering structures operating in the Far North. Taking into account the actual operating conditions on a real object, the design of the measuring device was developed; fiber Bragg gratings were used as sensitive elements of fiber-optic strain sensors and a temperature compensator. Taking into account the design parameters of the researched pile foundation, a spatial topology and a switching circuit for measuring devices were developed, and the monitoring process was launched. It is shown that the developed system is an effective tool for monitoring the stress-strain state of the monitored object online.
Detection of echo signals from discontinuities due to the use of super-resolution procedures for the control of concrete piles by the impact method
Authors: Bazulin E. G
Published: April 2024

To control concrete piles, an impact method is used, which allows recording echo signals from the sole of the pile and from reflectors in it. However, the resolution of the measured echo signal is not high enough to confidently separate the reflected pulses and determine their phase. The use of the maximum entropy (ME) method allowed to increase the resolution of the echo signals obtained by the impact method in a concrete pile with a length of 3000 mm by about three times and confidently identify echo signals from artificial reflectors, both in the form of a disk with a thickness of 100 mm and in the form of a parallelepiped with a height of 300 mm. The use of the method of Compressive Sensing (CS) made it possible to increase the resolution of the same echo signals by about ten times. The main problem of the successful application of the ME and CS methods is the determination of the impulse response of a concrete pile upon impact. A method for estimating the pulse response from the processed echo signal is proposed.
Increasing the structural sensitivity of the residual magnetization and coercive force of steels
Authors: Sandomirski S. G
Published: April 2024

The statistical analysis of measurement results of residual magnetization Mr and magnetization Ms of technical saturation of structural steels shows that ratio KS = Мr/Мs is much less sensitive to changes in phase composition of steels than Mr. Taking into account and more precise measurement of KS than Mr, it is offered to use the parameter KS for magnetic structuroscopy of medium-carbon steels in practically important range of variation of tempering temperature instead of Mr and coercive force Нс. It is shown, that the magnetic parameter ξ = Нс /Мs , at heat treatments, changing phase composition and structure of steels, in some cases has less sensitivity, than parameter Нс, to the phase composition of steel. To improve the reliability of interpolation by analytical function of the experimental dependence between the magnetic parameter and steel hardness, it is proposed to use a logical function "if" - different functional dependence between the magnetic parameter and steel hardness, depending on the measured value of the magnetic parameter.
Features of propagation of lateral transverse ultrasonic wave in a flat layer of material
Authors: Shevaldykin V. G , Samokrutov A. A.
Published: April 2024

The features of propagation of ultrasonic pulses of a lateral transverse wave from a point source of vibrations on the surface of the layer are considered. The mechanism of transformation of this wave during reflections from the boundaries of the layer into a transverse wave beam directed to the surface of the layer at an angle close to 45° is described. Experimental confirmation of the excess of the amplitudes of the lateral wave signals over the signals of other waves propagating in the layer is presented.
Theoretical investigations of temperature compensation of the results of the diagnosis of polymer composites by the method of two optical fiber
Authors: Fedotov M. Yu.
Published: April 2024

The paper considers the advantages and disadvantages of existing methods for temperature compensation of data from fiber-optic sensors based on fiber Bragg gratings as part of an embedded system for simultaneous testing of deformation and temperature of polymer composite materials. It is shown that when external temperature testing is impossible, it is most expedient to implement the method of two optical fibers with different sensitivity to at least one of these parameters due to different dopants. Technological issues related to the formation of a spatial topology and the provision of an effective interrogation of the embedded optical system for monitoring polymer composite materials by the two-fiber method are considered. The results of theoretical researches of a linear model of temperature compensation, a model that takes into account the influence of cross sensitivity, as well as a quadratic model of temperature compensation of optical testing data are presented. It has been established that the linear model is the simplest, however, when using it, one should take into account the error associated with the inaccuracy of the approximation of optical inspection data by a linear function. At the same time, it is shown that in order to improve the quality and reliability of the results of optical testing, it is advisable to use a quadratic model of temperature compensation, which provides an error level comparable to the error of the fiber-optic sensor interrogator. The results obtained can be used to develop methods for the simultaneous testing of samples, as well as monolithic and three-layer structures from structural layered of polymer composite materials with limiting molding conditions (temperature not more than 180 °C, specific pressure not more than 0,7 MPa), as in the process of bench and other tests, and, in the future, in real operating conditions.
Application of acoustic emission and digital image correlation for detecting diffusion interlayers in dissimilar welded joints
Authors: Barat V. A , Marchenkov A. Yu. , Poroykov A. Yu , Karpova M. V , Bardakov V. V
Published: April 2024

The paper investigates the possibility of using the acoustic emission (AE) method to detect carbide and decarburized interlayers formed in dissimilar welded joints of austenitic and pearlitic steels during welding and subsequent operation.
A new look at the controllability of parts with complex configuration in penetrant testing
Authors: Kudinov I. I , Golovkov A. N , Vakhov V. V , Skorobogatko D. S , Generalov A. S
Published: April 2024

A method is proposed to determine uncontrolled areas of aircraft engine parts in penetrant testing, taking into account the specifics of applying developers of different types (all forms according to ISO 3452-3). The main technological factors affecting the testability of surfaces of parts of complex geometry are presented. A method has been experimentally tested, which makes it possible to determine the uncontrolled zones of engine parts in penetrant testing, due to the specifics of applying different forms of developers. It has been established that when carrying out penetrant testing of parts, especially with complex configurations/geometry, the existing technologies for applying developers may not ensure its high-quality application to all controlled surfaces of parts, as was previously assumed based on the results of an expert assessment. It has been experimentally proven that such structural elements of parts as holes are controlled to a depth much less than the diameter.
Automated crack detection and a web tool using image processing techniques in concrete structures
Authors: Kumar Chandan , Sinha Ajay Kumar
Published: April 2024

Cracks indicates the real time deformity in concrete structures. It is characterized as discontinuity in terms of shape and size of the concrete structures. To ensure the structural health and safety, crack detection is an important task. The traditional methods of crack detection include visual introspection, ultrasonic and hand-held testing of crack. These methods require a high human intervention along with an experienced and skilled inspector. Moreover, these methods are subjective and time-consuming process which fails to identify the crack of the complex concrete structures properly. To overcome these issues, a grab-cut with improved Sobel has been proposed for automatic crack detection from the concrete structures. The proposed method works as a two-step model where cracks regions are segmented in the first step and a precise crack assessment is performed in the second step. Furthermore, to improve the efficacy of Sobel, the mask is modified with the aid of local variance of the image instead of using conventional mask of the filter. For the experimentation study, the images of self-prepared concrete sample have been acquired. The effectiveness of the proposed method has been compared with respect to various pre-existing methods like Sobel, Prewitt, Robert, LoG, Zero Cross and Canny. The comparative qualitative result exhibits that the proposed method surpasses the outcomes of the other pre-existing methods. Additionally, for easy implementation and application point of view a web tool of the proposed method has been developed. The web tool can be utilised by the civil infrastructure maintenance agency and construction engineers in the task of structure maintenance.
Tangential eddy current probe for testing of soldered joints of busbars in electrical machines
Authors: Gorbunov A. E , Ivkin A. E , Solomenchuk P. V
Published: April 2024

The article considers nondestructive testing of soldered lap joints of electric machines by means of a two-element eddy current tangential probe, excitation and measuring windings of which are placed on both sides of the test object. To ensure shielding from closely located current-conducting elements two active shielding windings are used. Using the tangential probe and reference blocks, replicating the shape and dimensions of the tested joint and imitating 0% and 100% soldering, allows measurement of soldering of busbar lap joints.
Parametric study of anomaly detection models for defect detection in infrared thermography
Authors: Vesala G. T , Ghali V. S , Naga prasanthi Y. , Suresh B.
Published: April 2024

In the current NDT 4.0 revolution, machine learning and artificial intelligence have emerged as the major enablers for non-destructive testing and evaluation (NDT&E) of industrial components. However, recent developments in active thermal NDT (TNDT) support its use as a practical method for checking a range of industrial components. Additionally, recent post-processing research in TNDT has developed several machine learning models to replace human interaction and offer automatic defect detection. However, the smaller area of the flaws and their related few thermal profiles than the wide sound area, leading to imbalanced datasets, make it difficult to train a supervised deep neural. Recently added to TNDT are anomaly detection models and one-class classifiers, both of which are commonly applied machine learning models to real-world issues. The accuracy and other important metrics in autonomous defect detection are influenced by the hyper-parameters of these models, such as contamination factor, volume of training data, and initialization parameter of the relevant model. The current paper investigates how initialization parameters affect these models’ TNDT capabilities for automated flaw detection. Using quadratic frequency modulated thermal wave imaging (QFMTWI), a carbon fiber-reinforced polymer specimen with variously sized artificially produced back-holes at different depths is examined. A good hyper-parameter for automatic flaw identification is chosen after qualitatively comparing testing accuracy, precision, recall, F-score, and probability.
Automatic segmentation by the method of interval fusion with preference aggregation when recognizing weld defects
Authors: Muravyov S. V , Nguyen D. C
Published: April 2024

Quality control of welding is usually carried out during the visual inspection process and is highly dependent on an operator experience. In the paper, it is proposed an approach to automatic detection and classification of a defective region, where segmentation of the analyzed photographic image of a weld (i.e., its division into defective and defect-free regions) is performed using the region growing procedure. The starting points for this procedure are selected by the authors' robust method of interval fusion with preference aggregation (IF&PA) on the base of image histogram analysis. Testing of the proposed approach for real life photographic images showed its ability to detect different types of weld defects with higher accuracy compared to traditional methods such as Otsu method and k-means.
TO THE BIRMAN–KREIN–VISHIK THEORY
Authors: Malamud M. M.
Published: April 2024

Let A ≥ mA 0 be a closed positive definite symmetric operator in a Hilbert space ℌ, let \({{\hat {A}}_{F}}\) and \({{\hat {A}}_{K}}\) be its Friedrichs and Krein extensions, and let ∞ be the ideal of compact operators in ℌ. The following problem has been posed by M.S. Birman: Is the implication A–1 ∈ G∞ ⇒ (\({{\hat {A}}_{F}}\) )–1 ∈ G∞(ℌ) holds true or not? It turns out that under condition A–1 ∈ G∞ the spectrum of Friedrichs extension \({{\hat {A}}_{F}}\) might be of arbitrary nature. This gives a complete negative solution to the Birman problem.Let \(\hat {A}_{K}^{'}\) be the reduced Krein extension. It is shown that certain spectral properties of the operators (\({{I}_{{{{\mathfrak{M}}_{0}}}}}\) + \(\hat {A}_{K}^{'}\))–1 and P1(I + A)–1 are close. For instance, these operators belong to a symmetrically normed ideal G, say are compact, only simultaneously. Moreover, it turns out that under a certain additional condition the eigenvalues of these operators have the same asymptotic.Besides we complete certain investigations by Birman and Grubb regarding the equivalence of semiboubdedness property of selfadjoint extensions of A and the corresponding boundary operators.
ON THE CONCENTRATION OF VALUES OF j-CHROMATIC NUMBERS OF RANDOM HYPERGRAPHS
Authors: Denisov I. O. , Shabanov D. A.
Published: April 2024

The paper deals with the study of the limit distribution of the \(j\)-chromatic numbers of a random k-uniform hypergraph in the binomial model \(H(n,k,p)\). We consider the sparse case when the expected number of edges is a linear function of the number of vertices \(n\), i.e. is equal to \(cn\) for \(c 0\) not depending on \(n\). We prove that for all large enough values of \(c\), the \(j\)-chromatic number of \(H(n,k,p)\) is concentrated in one or two consecutive numbers with probability tending to 1.
NONLOCAL PROBLEMS WITH GENERALIZED SAMARSKY-IONKIN CONDITION FOR SOME CLASSES OF NONSTATIONARY DIFFERENTIAL EQUATIONS
Authors: Kozhanov A. I.
Published: April 2024

In this paper, we study the solvability of boundary value problems that are nonlocal with respect to the spatial variable for one-dimensional parabolic equations, as well as for some equations of the Sobolev type. Existence and uniqueness theorems are proved regular solutions – namely, solutions having all the derivatives generalized in the sense of S.L. Sobolev entering the corresponding equation.
IDENTIFICATION OF NODAL POINTS OF ELASTIC INCLUSION IN ELASTIC PLANE
Authors: Shifrin E. I. , Kaptsov A. V.
Published: April 2024

A geometric inverse problem of identifying an isotropic, linearly elastic inclusion in an isotropic, linearly elastic plane is considered. It is assumed that constant stresses are given at infinity, and the displacements and acting loads are known on some closed curve enclosing the inclusion. In the case when the inclusion is a quadrature domain, a method for identifying its nodal points has been developed. A numerical example is considered.
Training Mediated by Organizational Culture and Moderated by Organizational Commitment and Leadership as Control Variables
Authors: Sjarifudin Didin , Wahdiniawati Siti Annisa , Untari Dewi , Sidjabat Sonya , Basuki Carola
Published: April 2024

The purpose of this research article is to find out whether there is an influence between variables in this study. This study used a quantitative research approach. The population consisted of 65 supervisors, whose online questionnaire was distributed to several manufacturing companies in Jababeka in January – February 2024, resulting in 65 responses. The sample size remains 65 supervisors. The collected data was analyzed through multiple regression analysis using SEM PLS series 4. Before conducting data analysis, several tests were carried out to determine the significance between variables both individually and simultaneously. Leadership is more instrumental in shaping organizational commitment than training. Therefore, companies need to pay attention to leadership development as one of the strategies to increase the level of employee commitment to the organization.
Determinants of Corporate Performance in One of Indonesia's Foreign Banks
Authors: Nurfalaq Dedi , Christian Michael
Published: April 2024

This research aims to assess the impact of organizational learning and leadership style on corporate performance (CP), with organizational culture acting as a moderator. The study was carried out at an Indonesian bank that is owned by the South Korean government. Therefore, this research will examine the impact of South Korean business culture, which is unfamiliar territory. This study employs a quantitative methodology. The findings of this study demonstrate that organizational learning significantly impacts business performance. Moreover, the leadership style also has an impact on the overall functioning of the company. Similar outcomes are also demonstrated in the case of organizational culture, which has an impact on corporate performance. Organizational culture plays a role in influencing organizational learning and corporate performance. Organizational culture does not have a moderating effect on the relationship between leadership style and business performance, as evidenced by many findings.
Pengaruh Return On Asset, Return On Equity, dan Earning Per Share Terhadap Harga Saham Pada Perusahaan Manufaktur Sektor Farmasi di Bursa Efek Indonesia
Authors: Irmansyah Irmansyah , Fitria Nita , Nofrivul Nofrivul , Saleh Sri Madona
Published: April 2024

This research aims to determine the effect of Return On Assets (ROA), Return On Equity (ROE), and Earning Per Share (EPS) on share prices in pharmaceutical sector manufacturing companies listed on the Indonesia Stock Exchange from 2018 to 2022. This research uses the method quantitative with secondary data sources. This research uses the analysis method T Test (partial), F Test (simultaneous), and company multiple linear regression. The analysis tool used is Eviews 10. The results of this research are that the variables Return On Assets (ROA) and Return On Equity (ROE) have no influence on share prices in pharmaceutical sector manufacturing companies on the Indonesian Stock Exchange in 2018-2022. The Earning Per Share (EPS) variable has an influence on share prices in pharmaceutical sector manufacturing companies on the Indonesian Stock Exchange in 2018-2022. The variables Return On Assets (ROA), Return On Equity (ROE), and Earning Per Share (EPS) influence share prices in pharmaceutical sector manufacturing companies on the Indonesian Stock Exchange in 2018-2022
Analisis Strategi Pengembangan Usaha Batiah Anis Baduih di Nagari Simawang Kecamatan Rambatan Kabupaten Tanah Datar
Authors: Sari Fauziah Elna Novita , Pasrizal Himyar
Published: April 2024

The aim of this research is to determine the internal and external factors in developing the Anis Baduih batiah business in Nagari Simawang, Rangkat District, Tanah Datar Regency and to explain the strategy for developing the Anis Baduih batiah business in Nagari Simawang, Rangkat District, Tanah Datar Regency. The research method uses a qualitative approach. Data collection techniques through observation, interviews and documentation. The research results show that Batiah Anis Baduih Business has tried to carry out development activities. The results of this research show that Anis Baduih's batiah business has internal factors in developing the business, especially the experience and expertise possessed by Mrs. Anis. Meanwhile, external factors in Anis Baduih's batiah business have not been maximized because the promotion process is only through word of mouth and has not used social media properly, so the market share is relatively small. The lack of collaborative partners in Anis Baduih's batiah business has had an impact on the business. It would be better if Anis Baduih's batiah business development strategy uses communication channels in the form of social media to promote Anis Baduih's batiah business, as well as establishing key partnerships to the maximum
Pengaruh Orientasi Pasar,Orientasi Kewirausahaan,dan Kreativitas Strategi Pemasaran yang Diintervening Inovasi Terhadap Kinerja Bisnis di Dama Group
Authors: Putri Meagika Surya , Nofrivul Nofrivul , Mirawati Mirawati , Marlin Khairul
Published: April 2024

The aim of this research is to determine the influence of market orientation, entrepreneurial orientation and marketing strategy creativity intervening with innovation on business performance in the Dama Group. The research was conducted using a quantitative approach. The data analysis technique uses Structural Equation Modeling (SEM) analysis with smartPLS version 4.1.0.0. Based on the research results, it was found that market orientation variables, entrepreneurial orientation and marketing strategy creativity had an influence on business performance variables in the Dama Group. The variables market orientation, entrepreneurial orientation and marketing strategy creativity influence the innovation variable at Dama Group. The innovation variable has no effect on the business performance variable at Dama Group. The market orientation variable has no effect on business performance where innovation intervenes at Dama Group. The entrepreneurial orientation variable has no effect on business performance where innovation intervenes at the Dama Group. The marketing strategy creativity variable has no effect on business performance where innovation intervenes at Dama Group.
Book 2. Startup projects and their scientific and technical support.
Authors: Shishlyannikov Oleg
Published: April 2024

Стартап проекты и их виртуальное научно-техническое сопровождение в целях акселерации процесса разработки Книга в 4 частях Часть 2 – Особенности организации , проведения и контроля инновационных работ в условиях стартапа и в технологическом инкубаторе ; Использование ТРИЗ и АРИЗ и их старых и новых методов и приёмов достижения идеального конечного результата
Innovative Composite Materials Based on Graphite
Authors: Kolesnikova Olga
Published: April 2024

В наиболее эффективных электрохимических реакторах , разработанных в рамках программ по созданию систем очистки и регенерации технологической воды без применения химических реагентов , ткани из углеродных композитов , обеспечивают практически все преимущества перед другими альтернативными технологиями. Название этих тканей Этан и Хортица и они являются инновационным продуктом предприятия УКРУГЛЕКОМПОЗИТ из города Запорожье. Учитывая тот необычный эффект , который приобретает электрохимический реактор при использования этих композитных тканей в качестве электродов и контактных систем для электродов, можно сделать предварительный вывод о том , что возможно эти материалы в своё время не были достаточно исследованы и квалифицированы на предмет их соответствия критериям нано – композитного материала Эти материалы применяются уже более 10 лет и постоянно открываются всё более интересные свойства и качества и , при этом в научных публикациях появляется всё больше сообщений о работах по развитию композитных материалов их углерода и его модификаций. Практический опыт в непроизводственных областях показывает , что и здесь имеется громадный резерв в целевом и эффективном применении такого рода материалов , как например в технике золочения при реставрации Применение этих материалов позволяет избавиться от многих застаревших проблем , в частности , - проблем , связанных с краевым эффектом Учитывая исключительный эффект от комплексного применения этих материалов , учёные и исследователи продолжают поиски
Analyzing the Effects of Mobile Assisted Language Learning on Learner Autonomy: A Quasi-Experimental Study
Authors: Estrella Felix
Published: April 2024

The advent of mobile technology has led to a significant shift in language learning, with an increasing number of learners now using mobile devices to enhance their learning experience. However, little is known about the impact of mobile-assisted language learning (MALL) on learner autonomy, a key indicator of successful language learning in the Ecuadorian context. This study aims to bridge this gap. A mixed-methods quasi-experimental research design was chosen to achieve this aim. A survey and semi-structured interviews were the chosen data collection tools. Ninety Ecuadorian undergraduate polytechnic students, divided equally into control and experimental groups, participated in this investigation. The quantitative results were not statistically significant in identifying a positive change in learner autonomy after the intervention. Nonetheless, learners admitted having had a change in their autonomy levels during the interviews.
Tumor Lesions in the Caspian White Fish (Rutilus kutum)
Authors:   Inland Waters Aquaculture Research Center, Iranian Fisheries Science Research Institute (IFSRI), Agriculture Research Education and Extension Organization (AREEO), Bandar-e Anzali, Iran., Ghasemi Mohaddes , Sharifpour Issa ,   Iranian Fisheries Sciences Research Institute (IFSRI), Agricultural Research, Education and Extension Organization, Tehran, Iran., Haghighi Karsidani Somayeh ,   Department of Fishery, Faculty of Natural Resources, Bandar Anzali Branch, Islamic Azad University, Bandar-e Anzali, Iran., Eynizadeh Zahra ,   Department of Animal Sciences and Marine Biology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran., Azarabad Hasti ,   Department of Pathology, Hamidreza Fattahian Pet Hospital, Tehran, Iran.
Published: April 2024

Background: Due to the multifactorial etiology, tumor manifestation in any vertebrate species may become a critical issue. This topic requires more consideration for species in aquatic ecosystems as an enclosed habitat. In addition, knowledge about oncogenesis in the aquaculture industry enhances the quality of products and its earned benefits. Objectives: This study investigated the tumor lesions, their characteristics, and probable causes, in the most commercially important fish in the southern Caspian Sea: Caspian white fish (Rutilus kutum). Methods: To accomplish this goal, after gross pathology of more than 20 cases, histopathological examinations and electron microscopic assays were employed. Results: The findings confirmed squamous cell carcinoma and squamous cell papilloma in the examined cases. Furthermore, the virus-like particles were clearly observed in the transmission electron microscopy results, indicating the probable viral etiology for these neoplastic lesions in Caspian Kutum. Conclusion: This study is the first to report the tumor prevalence in fish species of the southern Caspian Sea, which could be an alert for the mentioned ecosystem’s health and the whole aquaculture industry.
Is The Idiosyncratic Volatility Puzzle Driven By A Missing Factor?
Authors:   The Institute of Management and Economy Research, Kim Hanjun , Sohn Bumjean
Published: April 2024

Purpose - We investigate whether a potential missing pricing factor plays a significant role in the idiosyncratic volatility puzzle. Design/methodology/approach - We theoretically show how a missing pricing factor can affect the idiosyncratic volatility puzzle, and also show how to get around the problem empirically. We adopt the Fama-French five factor model for the estimation of the idiosyncratic risk and use randomly constructed portfolios as test assets. Findings - We find that a missing factor does not drive the idiosyncratic volatility puzzle. Thus, we conclude that the idiosyncratic volatility does affect the risk premium of its stock. Research implications or Originality - The Fama-French five factor model does a pretty good job in explaining the risk premiums of stocks, and it can be used to reliably estimate idiosyncratic risk of stocks.
The Productivity Impact of Working from Home and the Moderating Effect of Task Characteristics: An Empirical Investigation of Field Data
Authors:   The Institute of Management and Economy Research, Kim Jae-Young , Lee Dong-Joo
Published: April 2024

Purpose - This study aims to empirically identify the quantitative effects of work from home (WFH) on employee productivity using field data. Design/methodology/approach - Based on large-scale field data from a South Korean company which introduced the WFH arrangement in 2020, we conducted fixed effect and moderating effect analyses using individual-level panel data over sixty-three weeks. Findings - The empirical analysis generated several findings. It was found that overall, WFH has a positive effect on productivity. However, the productivity impact of WFH was found to vary depending on task characteristics. Specifically, WFH led to over 20% increase in productivity for simple and repetitive tasks. On the other hand, no significant productivity impact was observed for professional and knowledge-based tasks. Research implications or Originality - As the first study based on field data from South Korea, this study offers convincing causal evidence of the moderating impact of task characteristics on the relationship between WFH and productivity. Further, the above findings provide managers with practical insights concerning their work arrangement decisions.
A Study on Big Data-Driven Business in the Financial Industry: Focus on the Organization and Process of Using Big Data in Banking Industry
Authors:   The Institute of Management and Economy Research, Kim Gyu-Bae , Kim Yong Cheol , Kim Moon Seop
Published: April 2024

Purpose - The purpose of this study was to analyze cases of big data-driven business in the financial industry, focusing on organizational structure and business processes using big data in banking industry. Design/methodology/approach - This study used a case study approach. To this end, cases of two banks implementing big data-driven business were collected and analyzed. Findings - There are two things in common between the two cases. One is that the central tasks for big data-driven business are performed by a centralized organization. The other is that the role distribution and work collaboration between the headquarters and business departments are well established. On the other hand, there are two differences between the two banks. One marketing campaign is led by the headquarters and the other marketing campaign is led by the business departments. The two banks differ in how they carry out marketing campaigns and how they carry out big data-related tasks. Research implications or Originality - When banks plan and implement big data-driven business, the common aspects of the two banks analyzed through this case study can be fully referenced when creating an organization and process. In addition, it will be necessary to create an organizational structure and work process that best fit the special situation considering the company's environment or capabilities.
Why Do We Make Impulse Purchases in Live-streaming E-commerce?
Authors:   The Institute of Management and Economy Research, Jiang Wenyan , Bang Youngsok
Published: April 2024

Purpose - This study explores the causes behind the high rate of impulse purchases in live streaming e-commerce. Design/methodology/approach - The research model is empirically validated with survey data collected from 324 respondents in China, using the Partial Least Squares (PLS) methodology. Findings - We found that the interactivity and visibility of live streaming are key in creating para-social relationships and perceived presence, leading to customers' impulse purchases. Research implications or Originality - This study deepens the understanding of consumers' impulse purchases in live-streaming e-commerce, revealing that para-social relationships and perceived presence developed through real-time interactions can increase impulse buying. It also highlights the differences between relationship-oriented and task-oriented interactions in fostering customers' perceived presence and para-social relationships in live streaming.
Study on the Influencing Factors of Business Performance and Loyalty in O2O Industry: Focusing on the Food Delivery Apps
Authors:   The Institute of Management and Economy Research, Hyun Dae Yong , Kim Sun-Young , Lee Byungheon
Published: April 2024

Purpose - With the increase of non-face-to-face activities due to the spread of COVID-19, O2O industry has grown rapidly which reduces contact points between suppliers and consumers. O2O platform is now recognized as an indispensable channel of distribution, but the voice is getting louder that it is necessary to check how it contributes to the performance of suppliers or how its fee system or contract terms affects the expansion of O2O industry as the leading companies tend to monopolize the market. Design/methodology/approach - In this study, the scope was limited to the restaurant industry in which transactions are the most active among the O2O industry and a regression analysis was done on 775 businesses that had used guarantor service from the Seoul Credit Guarantee Foundation. Findings - Analysis on the impact of O2O platform system, information, and service quality on the business performance of the sole proprietors revealed that the system quality represented by ease of use and the information quality determined by level of timely, accurate and reliable information provided to the consumers have a statistically significant effect on the improvement of business performance. In addition, the effect of business performance on the loyalty measured by the likelihood of users continuing to use the service as well as recommending it to others was moderated by the satisfaction with contract terms, not by the fee system. Research implications or Originality - Although the number of O2O platform providers has increased manyfold, the membership rate is no more than 20%, which means that the small business owners are still struggling with digital transformation. In order for the O2O industry, which is now commonplace, to form a healthy ecosystem that satisfies both suppliers and consumers, the standard contract guidelines that are acceptable to both parties must be established and the O2O providers must offer services that help suppliers to improve performance.
The Impact of Chinese Land Supply Policies on the Real Estate Market
Authors:   The Institute of Management and Economy Research, Liu Yi-bo , Lee Yeon-jae , Shin Seung-woo
Published: April 2024

Purpose - This study aims to explore the relationship between housing and land prices, with a specific emphasis on the impact of government policies on these factors such as land supply quantity and the ratio of residential land to total land supplied. The goal is to identify the most effective government intervention strategies for controlling both housing and land prices. Design/methodology/approach - Data from 70 primary and medium-sized cities in China spanning from 2003 to 2017 are utilized in this research. The analysis employs a panel vector autoregressive (PVAR) model, with a primary focus on examining the relationships among housing prices, land prices, and government intervention policies. Findings - Housing and land prices are influenced by various factors. Through impulse response analysis and variance decomposition, it is observed that both housing and land prices are predominantly influenced by their internal dynamics, with comparatively weaker effects attributed to policy interventions. Research implications or Originality - By investigating the impact of government policies on housing and land prices, This study establishes a foundation for effective price control measures. Our study advocates for a comprehensive examination of China's land supply mechanism to enhance understanding of the pathways through which government policies influence the markets.
Foreign Tourists’ Experience Structure Visiting Cultural Tourism Resources in Jeju using Co-occurrence Network Analysis: Focused on Online Review and Grade of Global OTA
Authors:   The Institute of Management and Economy Research, Yun Hee-Jeong
Published: April 2024

Purpose - This study conducts the co-occurrence analysis, one of the social network analysis using global OTA’s online reviews and grades in order to understand the experience structure of foreign tourists visiting cutural tourism resources in Jeju, Korea. Design/methodology/approach - For this purpose, this study selects 6 cultural tourism resources in Jeju as the study sites, and collects qualitative review data (noun, adjectives, and verb) and quantitative grade data. Findings - The co-occurrence network analysis between words and grade of market and street shows that the grade of 5 appears the most simultaneous with pork, buy, lot, try, fresh, black, food, price, seafood, local, market, good, street, etc. and the grade of 1 connects with small, dish, better, taste, etc. And the co-occurrence network analysis between words and grade of tradition and folklore shows that the grade of 5 appears the most simultaneous with village, place, museum, visit, time, life, culture, women, diver, use, lot, etc. and the grade of 1 connects with minute, spend, room, recommend, honey, etc. Research implications or originality - The above research results are relevant in order to find out the core experience of foreign tourists using online review and grade generated by foreign tourists and use as the important information to develop the strategies related to the planning and management of cultural tourism resources.
An Understanding of Keyword Networks on Research Trends on Jeju Tourism and Sports Tourism
Authors:   The Institute of Management and Economy Research, Kim Joonhyeong Joseph , Choi Sung-Hun
Published: April 2024

Purpose - The purpose of this study was to conduct a preliminary study to identify key trends on research articles indexed in KCI in relation to tourism in Jeju and sports tourism. Design/methodology/approach - Information regarding research articles focused on Jeju tourism and sports tourism indexed in KCI (145 and 120 articles respectively) were collected and finally abstract written in Korean of 100 and 91 articles on sports tourism and Jeju tourism respectively were chosen for the further analysis after removing redundant articles. R program was used to analyze keyword frequencies, co-occurring terms, and degree/betweeness centrality measures and visualize the keyword network results. Findings - Event, marketing, content, program, implication, service, stadium, and tourism destination have been identified as keywords with highest frequencies among research on sport tourism, whereas tourism destination, image, brand, content, data, Chinese, satisfaction, eco-tourism service, place of arrival were highly appearing terms among research on Jeju tourism. Research implications or Originality - This study highlighted that Jeju has been interlinked with a range of terms such as programs influencing Jeju tourism, natural environment, tourism-related resources (e.g., museums, dramas, etc.), whereas sports has been closely related to sports event and vaiours types of sports (e.g., bicycle, staking, and scuber), but not to Jeju-do.
An Empirical Analysis on Performance Inconsistency among Environmental, Social and Governance Components of ESG Ratings
Authors:   The Institute of Management and Economy Research, Park Minjung
Published: April 2024

Purpose - The purpose of this study is to empirically investigate the degree of performance inconsistency among the Environmental, Social and Governance ratings. Design/methodology/approach - This study performs regression analysis using the widely used ESG ratings published by the Korea Institute of Corporate Governance and Sustainability. Findings - The results show that firms often do not show consistent performance across the Environmental, Social and Governance aspects, with excellent performance on one aspect but mediocre or poor performance on another. The paper also finds some degree of firm-level persistence in such performance inconsistency, suggesting that the traits of the firm and the industry the firm belongs to might influence whether a firm shows inconsistent performance across the three aspects. Research implications or Originality - This paper highlights the need for researchers and practitioners to understand the underlying behavior of the individual E, S and G ratings, instead of taking them as given, in order to properly design their analyses.