• Advances in nano research
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• v.16 no.4
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• pp.325-340
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• 2024

There are several novel uses for dispersing many nanoparticles into a conventional fluid, including dynamic sealing, damping, heat dissipation, microfluidics, and more. Therefore, melting heat and mass transfer characteristics of a 3-D MHD Hybrid Nanofluid flow over a rotating disc with presenting dufour and soret effects are assessed numerically in this study. In this instance, we investigated both ferric sulfate and molybdenum disulfide as nanoparticles suspended within base fluid water. The governing partial differential equations are transformed into linked higher-order non-linear ordinary differential equations by the local similarity transformation. The collection of these deduced equations is then resolved using a Chebyshev spectral collocation-based algorithm built into the Mathematica software. To demonstrate how different instances of hybrid/ nanofluid are impacted by changes in temperature, velocity, and the distribution of nanoparticle concentration, examples of graphical and numerical data are given. For many values of the material parameters, the computational findings are shown. Simulations conducted for different physical parameters in the model show that adding hybrid nanoparticle to the fluid mixture increases heat transfer in comparison to simple nanofluids. It has been identified that hybrid nanoparticles, as opposed to single-type nanoparticles, need to be taken into consideration to create an effective thermal system. Furthermore, porosity lowers the velocities of simple and hybrid nanofluids in both cases. Additionally, results show that the drag force from skin friction causes the nanoparticle fluid to travel more slowly than the hybrid nanoparticle fluid. The findings also demonstrate that suction factors like magnetic and porosity parameters, as well as nanoparticles, raise the skin friction coefficient. Furthermore, It indicates that the outcomes from different flow scenarios correlate and are in strong agreement with the findings from the published literature. Bar chart depictions are altered by changes in flow rates. Moreover, the results confirm doctors' views to prescribe hybrid nanoparticle and particle nanoparticle contents for achalasia patients and also those who suffer from esophageal stricture and tumors. The results of this study can also be applied to the energy generated by the melting disc surface, which has a variety of industrial uses. These include, but are not limited to, the preparation of semiconductor materials, the solidification of magma, the melting of permafrost, and the refreezing of frozen land.

• Smart Media Journal
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• v.13 no.5
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• pp.33-44
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• 2024

Chungbuk has various regional characteristics in terms of population composition by region, industrial facilities, and distribution of emergency medical institutions. However, there are no studies yet that have analyzed regional characteristic factors related to the occurrence characteristics of cardiac arrest patients. Therefore, this study provided basic data to establish a response system for OHCA patients suitable for the characteristics of the Chungcheongbuk-do region by analyzing the characteristics of OHCA patients and the transfer status of 119 paramedics in Chungcheongbuk-do. This study is a retrospective study that analyzed 1,188 cardiac arrest patients transferred by ambulance based on raw data from the survey on acute cardiac arrest in Chungbuk (2020). There are a total of 11 emergency medical institutions in Chungbuk-do, which are concentrated in city-level areas, so the transfer time of patients to hospitals in county-level areas was delayed. In the county-level area, the frequency of dispatch of special paramedics was relatively small, and the frequency of administration of cardiac arrest drugs to help resuscitate cardiac arrest patients was also low. In conclusion, efforts should be made to improve accessibility of emergency medical services (deployment of emergency vehicles in marginal areas, proper placement of emergency medical institutions, etc.), to promote prevention of traumatic cardiac arrest patients, and to expand the scope of work to strengthen the first aid expertise of paramedics.

• Industry Promotion Research
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• v.9 no.2
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• pp.13-22
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• 2024

The purpose of this study is to derive passenger trends and change rates for each airline and identify directionality and synchronization phenomenon. Data by each airlines was collected from the National Statistics Forum of Statistics Korea, and we used a total of 156 monthly data from January 2011 to December 2023. In this study, the rate of change was calculated for domestic Full Service Carriers (Korean Air, Asiana Airlines) and Low Cost Carriers (Jeju Air, Jin Air, T'way, foreign airlines). As a result of the analysis, the correlation was found to be high for KOREA in that order: Asiana, Korean Air, Jeju Air, T'way, Jin Air, foreign airlines. The rate of increase was highest in that order: T'way, Jin Air, Jeju Air, foreign airlines, Asiana, Korean Air. In the Scatter analysis, Asiana and Korean Air showed a very strong synchronization with KOREA. In addition, Jeju Air, T'way, Jin Air and foreign airlines also showed the same direction toward KOREA to a certain degree. In the Box-Box Plot analysis, it was determined that each airline experienced a number of unusual sudden fluctuations due to the outbreak of COVID-19. Passengers have a wider range of choices due to the emergence of Low Cost Carriers, and as a result, expectations for airline service are increasing. Airlines will need to make appropriate environmental improvements to satisfy these needs for corporate development.

• Information Systems Review
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• v.22 no.3
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• pp.99-118
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• 2020

At present, our society is developing into the intelligent information society in the wave of the 4th industrial revolution, and this change will have the positive effect of innovating all industry fields. However, due to the duality of technology, there will be positive and negative effects. With intelligence, threats to cyber dysfunction such as hacking, terrorism, privacy infringement, and illegal content distribution will become more serious. Until now, the security system of the Internet has been a proactive security system, but in recent years, a proposal for a trust network, a preventive security system, has been introduced. Therefore, this study aims to analyze the possibility of resolving cyber dysfunction of intelligent information society about Bright Internet, one of trust network technologies. This study defines the cyber dysfunction of the intelligent information society and analyzes the perceptions of changes in the cyber dysfunction of the intelligent information society on the introduction of the five principles of the Bright Internet. The change of cyber dysfunction severity of the intelligent information society due to the introduction of the trust network is analyzed to reflect the technical and social demands. This work will guide the structure of the trust network and the direction of practical technological introduction and its influence.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.1
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• pp.85-97
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• 2024

Objectives: This study was intended to investigate the revision status of the occupational exposure standards for aluminum at home and abroad; to investigate worker exposure at domestic aluminum manufacturing and handling workplaces; to conduct social and economic evaluation for the revision of domestic aluminum exposure limits. Methods: We investigated the current status of occupational exposure limits for aluminum at home and abroad, and analyzed supporting data. An exposure survey was conducted targeting domestic aluminum manufacturing and handling workplaces. Based on these, revised aluminum occupational exposure limits were proposed. Results: The major aluminum exposure limits at home and abroad show a notable difference. The toxicity of aluminum, which was revealed through animal experiments and epidemiological investigations. The average concentration of aluminum in the air at 12 workplaces was 0.016 mg/m³, and the maximum was 0.0776 mg/m³. When total dust and respiratory dust were measured side by side and simultaneously for the same process, 12.1% of the total mass concentration of aluminum dust was respiratory dust. As a result of measuring and comparing the size distribution of dust with an optical particle counter in real time, 48.1% of the total dust in the form of welding fume and pyro-powder was respiratory dust. Based on the literature review and workplace survey, three proposals for changing the aluminum exposure limit were proposed. Proposal (1): For all types, 10 mg/m³ is unified as the exposure limit except for soluble salts and alkyls. Proposal (2): 1(R) mg/m³ as the exposure limit for all forms except soluble salts and alkyl. Proposal (3): 1(R) mg/m³ for pyro-powder and welding fume, and 10 mg/m³ for metal dust, aluminum oxide, and insoluble compounds as exposure standards. A pyro-powder was defined as dry aluminum powder of 200 mesh size (74 ㎛) or smaller (larger size classified as metal dust). Reason for setting: In the workplace survey, the ratio of respiratory dust to total dust was analyzed to be about 1:10, so it was judged that the domestic standard and the ACGIH standard were compatible. Conclusions: In all scenarios according to the revision of the exposure standard, the B/C ratio was greater than 1 or only benefits existed, so it was evaluated as sufficiently reasonable as a result of the socio-economic evaluation.

• Journal of Practical Agriculture & Fisheries Research
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• v.26 no.1
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• pp.22-29
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• 2024

In this study, we summarized the definition of smart vegetable seedling production technology, analysis of smart seedling production system, a hardware and software configuration model for smart seedling production system, research and development trends in smart seedling production system, and proposed future research and development plans for smart seedling production technology. Smart vegetable seedling production is a data-based seedling production, management, and distribution system that utilizes 4th Industrial Revolution technology to improve seedling productivity and quality. The production of vegetable seedlings using smart seedling production technology can be efficiently managed by collecting, analyzing, and managing information on seedlings, environment, and tasks at each stage of production by linking with the smart seedling integrated management system. However, there is still a lack of standardization of seedling standards and quality for each vegetable crop to establish smart seeding production technology, as well as development of smart seedling production element technology, which requires national wide R&D support.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.471-479
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• 2023

In In-situ radioactivity measurement techniques, efficiency calibration models use predefined models to simulate a sample's geometry and radioactivity distribution. However, simplified efficiency calibration models lead to uncertainties in the efficiency curves, which in turn affect the radioactivity concentration results. This study aims to develop an efficiency calibration optimization methodology to improve the accuracy of in-situ gamma radiation measurements for byproducts from industrial facilities. To accomplish the objective, a drive mechanism for rotational measurement of an byproduct simulator and a sample was constructed. Using ISOCS, an efficiency calibration model of the designed object was generated. Then, the sensitivity analysis of the efficiency calibration model was performed, and the efficiency curve of the efficiency calibration model was optimized using the sensitivity analysis results. Finally, the radiation concentration of the simulated subject was estimated, compared, and evaluated with the designed certification value. For the sensitivity assessment of the influencing factors of the efficiency calibration model, the ISOCS Uncertainty Estimator was used for the horizontal and vertical size and density of the measured object. The standard deviation of the measurement efficiency as a function of the longitudinal size and density of the efficiency calibration model decreased with increasing energy region. When using the optimized efficiency calibration model, the measurement efficiency using IUE was improved compared to the measurement efficiency using ISOCS at the energy of ²²⁸Ac (911 keV) for the nuclide under analysis. Using the ISOCS efficiency calibration method, the difference between the measured radiation concentration and the design value for each simulated subject measurement direction was 4.1% (1% to 10%) on average. The difference between the estimated radioactivity concentration and the design value was 3.6% (1~8%) on average when using the ISOCS IUE efficiency calibration method, which was closer to the design value than the efficiency calibration method using ISOCS. In other words, the estimated radioactivity concentration using the optimized efficiency curve was similar to the designed radioactivity concentration. The results of this study can be utilized as the main basis for the development of regulatory technologies for the treatment and disposal of waste generated during the operation, maintenance, and facility replacement of domestic byproduct generation facilities.

• Journal of Service Research and Studies
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• v.14 no.3
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• pp.153-171
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• 2024

Recently, domestic universities have become more competitive among universities due to the Fourth Industrial Revolution and the rapid decline of population. As a result, universities are making great efforts to improve university service quality to enhance university competitiveness as they change from supplier-centered thinking to consumer-centered thinking. Despite the increasing importance of university service quality, research on service quality is mainly focused on companies, and research on service quality in the university education environment is insufficient. Therefore, this study aims to examine the influence relationship between university service quality, trust, reputation, and behavior intention. The results of this study are as follows. First, among the service quality of university, tangibility, assurance, and empathy were found to have a positive (+) effect on the trust of the university, but reliability was found to have no significant effect on the trust of the university. Second, among the service quality of university, tangibility, reliability, and empathy were found to have a positive (+) effect on the reputation of the university, but assurance was found to have no significant effect on the reputation of the university. Third, it was found that the trust of the university had a positive (+) effect on the behavior intention. Fourth, it was found that the university's reputation had a positive (+) effect on the behavior intention. Through the above research results, this study aims to derive an effective management plan for university service quality and to present a plan for establishing a differentiated operating strategy for universities that can respond to students' learning needs and changes in the times in the rapidly changing university education environment.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.19 no.4
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• pp.161-182
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• 2024

The study analyzed the rapidly growing food tech startup in South Korea, focusing on industry classification, core technological domains, investment stages, and growth trajectories. Utilizing the ERIS model, two innovative food tech startups, MyChef and CatchTable, were examined as case studies. Results revealed food tech startups are focusing on information technology and smart distribution technology-oriented solutions rather than traditional food production. This study also found that robotics and AI integration were key technology areas. Analyzing the emergence of food tech startups, investment stages, and cumulative investment amounts based on founding years revealed a trend of scaling operations through rounds of funding, especially after securing SERIES A and B funding. The period between 2014 and 2018 saw a dense concentration of food tech startup establishments, likely influenced by favorable conditions for technological innovation amid the Fourth Industrial Revolution. The high rate of strategic mergers and acquisitions and bankruptcy can be interpreted as the complexity inherent in the food tech industry. The case study of MyChef, which grew into HMR manufacturing, and Wad(CatchTable), which expanded into a restaurant reservation platform, derived the entrepreneurs, resources, industry, and strategic factors that served as success factors for food tech startups. This study has practical implications in that it provides entrepreneurs, investors, and policymakers in the food tech industry with insight and direction to develop strategies in line with market trends and technological changes and promote sustainable growth.

• Applied Chemistry for Engineering
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• v.35 no.5
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• pp.468-472
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• 2024

This study experimentally examined the separation performance of indole (IN) contained in crude methyl naphthalene oil (CMNO) by methanol extraction and then compared these results with formamide extraction. CMNO containing about 4.36% IN, which is attracting attention as an intermediate raw material such as medicine, essential amino acids, and perfumes, was used as a raw material, and methanol aqueous solution was used as a solvent, respectively. The increase in the initial volume fraction of water in the solvent (y_w,0) sharply decreased the distribution coefficient (m_IN) and yield (Y_IN) of IN, but conversely increased the selectivity of IN in reference to 2-methylnaphthalene (2MNA). An increase in the initial volume ratio of solvent to feed (E₀/R₀) increased m_IN, Y_IN, and 𝛽_IN,2MNA. In the range of 0.1 ≤ y_w,0 ≤ 0.3, m_IN and Y_IN of methanol extraction were approximately 1.9~5.9 times and 1.8~3.6 times greater than those of formamide extraction, respectively, whereas 𝛽_IN,2MNA of formamide extraction were 4.6~8.2 times greater than those of methanol extraction.