• Communications for Statistical Applications and Methods
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• v.30 no.5
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• pp.485-499
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• 2023

This study aimed to predict the number of meals served in a group cafeteria using machine learning methodology. Features of the menu were created through the Word2Vec methodology and clustering, and a stacking ensemble model was constructed using Random Forest, Gradient Boosting, and CatBoost as sub-models. Results showed that CatBoost had the best performance with the ensemble model showing an 8% improvement in performance. The study also found that the date variable had the greatest influence on the number of diners in a cafeteria, followed by menu characteristics and other variables. The implications of the study include the potential for machine learning methodology to improve predictive performance and reduce food waste, as well as the removal of subjective elements in menu classification. Limitations of the research include limited data cases and a weak model structure when new menus or foreign words are not included in the learning data. Future studies should aim to address these limitations.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.16 no.3
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• pp.151-167
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• 2012

In this paper, we investigate the dynamic behaviors of a one-prey and two-predator system with Holling-type II functional response and defensive ability by introducing a proportion that is periodic impulsive harvesting for all species and a constant periodic releasing, or immigrating, for predators at different fixed time. We establish conditions for the local stability and global asymptotic stability of prey-free periodic solutions by using Floquet theory for the impulsive equation, small amplitude perturbation skills. Also, we prove that the system is uniformly bounded and is permanent under some conditions via comparison techniques. By displaying bifurcation diagrams, we show that the system has complex dynamical aspects.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.215-222
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• 2020

Metformin is a recommended first-line therapy drug for type 2 diabetes patients. However, compared to other oral antidiabetic drugs (OAD), metformin has a large unit dosage, with bioavailability of 40-60%. This limiting bioavailability is because metformin is absorbed only in the upper gastrointestinal tract as a BCS class 3 drug. Hence, we propose that applying the Gastroretentive Drug Delivery System (GRDDS) and extending drug release time in the stomach will result in improved bioavailability. We selected the swelling type delivery system, as it is considered the most stable gastroretention technology compared to other GRDDSs. We modified the swelling excipient by using a natural swelling excipient to form a swelling tablet made of carrageenan and hydroxypropyl methylcellulose (HPMC). Our results indicate that the swelling complex tablet made of carrageenan and HPMC has a good swelling ability and shows required sustained release in a dissolution pattern. In addition, the carrageenan complex has a better swelling ability than the marketed metformin tablet, as determined by the ratio, (swelling ability)/(excipient weight). Taken together, our results indicate that the carrageenan complex can be developed as a good swelling excipient. Further optimizations are required for the commercialization of the carrageenan complex.

• Applied Chemistry
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• v.15 no.1
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• pp.25-28
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• 2011

A highly sensitive spectrofluorimetric method was developed for the determination of levodopa based on the formation of a ternary complex with Eu³⁺ in the presence of ethylenediaminetetraacetic acid. It was found that this complex manifests intense fluorescence at 591 and 613 nm with excitation at 372 nm and maximum intensity was obtained at 613 nm. Under the optimum conditions, the enhanced fluorescence intensity was proportional to the concentration of levodopa over the range of 3×10^-9-2.5×10^-7 mol L^-1 with limit of detection (LOD) of 4.37×10^-10 mol L^-1. The method offers higher sensitivity and selectivity which could be effectively applied for the determination of levodopa in pharmaceutical and biological samples.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.3
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• pp.380-391
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• 2015

Objectives: The objective of this study is to assess airborne particulate matter pollution and its effect on health of residents living near Ansim Briquette Fuel Complex and its vicinities. Also, this study measured and analyzed the concentration of TSP, $PM_{10}$, $PM_{2.5}$, and heavy metals which influences on the environmental and respiratory disease in Ansim Briquette Fuel Complex, Daegu, Korea. Methods: In this study, we analyzed various environmental pollutants such as particulate matter and heavy metals from Ansim Briquette Fuel Complex that adversely affected local residents's health. In particular, we verified the concentration distribution and characteristics of exposure for TSP, $PM_{10}$, and $PM_{2.5}$ among particulate matters, and heavy metals(Cd, Cr, Cu, Mn, Ni, Pb, Fe, Zn, and Mg). In that regard, the official test method on air pollution in Korea for analysis of particulate matter and heavy metal in atmosphere were conducted. The large capacity air sampling method by the official test method on air pollution in Korea were applied for sampling of heavy metals in atmosphere. In addition, we evaluated the concentration of seasonal environmental pollutants for each point of residence in Ansim Briquette Fuel Complex and surrounding area. The sampling measured periods for air pollutants were from August 11, 2013 to February 21, 2014. Furthermore, we measured and analyzed the seasonal concentrations(summer, autumn and winter). Results: The average concentration for TSP, $PM_{10}$, and $PM_{2.5}$ by direct influence area at Ansim Briquette Fuel Complex were 1.7, 1.4 and 1.9 times higher than reference region. In analysis results of seasonal concentrations for particulate matter in four direct influence and reference area, concentration levels for winter were generally somewhat higher than concentrations for summer and autumn. The average concentrations for Cd, Cr, Mn, Ni, Pb, Fe, and Zn in direct influence area at Ansim Briquette Fuel Complex were $0.0008{\pm}0.0004{\mu}g/Sm^3$, $0.0141{\pm}0.0163{\mu}g/Sm^3$, $0.0248{\pm}0.0059{\mu}g/Sm^3$, $0.0026{\pm}0.0011{\mu}g/Sm^3$, $0.0272{\pm}0.0084{\mu}g/Sm^3$, $0.4855{\pm}0.1862{\mu}g/Sm^3$, and $0.3068{\pm}0.0631{\mu}g/Sm^3$, respectively. In particularly, the average concentrations for Cd, Cr, Mn, Ni, Pb, Fe, and Zn in direct influence area at Ansim Briquette Fuel Complex were 1.9, 3.6, 2.1, 1.9, 1.4, 2.6, and 1.2 times higher than reference area, respectively. The continuous monitoring and management were required for some heavy metals such as Cr and Ni. Moreover, the average concentration in winter for particulate matter in direct influence area at Ansim Briquette Fuel Complex were generally higher than concentrations in summer and autumn. Also, average concentrations for TSP, $PM_{10}$, and $PM_{2.5}$ were from 1.5 to 2.0 times, 1.2 to 1.8 times, and 1.1 to 2.3 times higher than reference area, respectively. In results for seasonal atmospheric environment, TSP, $PM_{10}$, $PM_{2.5}$, and heavy metal concentrations in direct influence area were higher than reference area. Especially, the concentrations in C station were a high level in comparison with other area. Conclusions: In the results, some particulate matters and heavy metals were relatively high concentration, in order to understand the environmental pollution level and health effect in surrounding area at Ansim Briquette Fuel Complex. The concentration of some heavy metals emitted from direct influence area at Ansim Briquette Fuel Complex were relatively higher than reference area. In particular, average concentration for heavy metals in this study were higher than average concentrations in air quality monitoring station for heavy metal for 7 years in Deagu metropolitan region. Especially, the residents near Ansim Briquette Fuel Complex may be exposed to the pollutants(TSP, $PM_{10}$, $PM_{2.5}$, and heavy metals, etc) emitted from the factories in Ansim Briquette Fuel Complex.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.6
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• pp.128-140
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• 2003

The purpose of this research was to present characteristics for the classification of biotopes and classification method of biotopes as basic data for ecological landscape planning in Metropolitan Daegu. The results of this study were as follows. 1) The study identified fifteen characteristics for classification of biotopes. Ecological landscape characteristics were divided into structural and functional factors. There are six structural factors such an inclination, and nine functional factors such as temperature. 2) The study area was separated into sixty eight biotope types. For example, an industrial district was divided into two biotope types: a biotope type of an industrial district with abundant green space, and a biotope type of an industrial district with scarce green space. 3) In the result of cluster analysis using the average linkage method between groups, biotope groups were divided into fifteen clusters and biotope groups were divided into seven clusters. Each cluster was named according to the features of a descriptive statistics analysis. For example, cluster 8 was identified as a biotope type with an impermeable pavement rate of more than 90 percent and an afforestation rate under 10 percent. 4) Fifteen biotope groups were converted to land use patterns for remote application and utilization of urban biotope in city planning. Biotope groups of a building area beyond an intermediate floor with an afforestation rate under 20-30 percent was converted to a land use pattern such as a tall apartment complex or commercial district. When examining the characteristics that were established in this research, there was a limit to achieve the objective of grade-classification because of a lack of related basic data. The research of landscape ecological characteristics for the classification of biotopes could not be completed due to a lack of time and resources, thus the study of ecological landscape characteristics will be accomplished over time.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.3
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• pp.182-194
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• 2009

This study was conducted to evaluate health status and to propose health protection measures of irregular plant construction workers in Yoesu National Industrial Complex (YNIC). The status of safety and health management was examined in five areas including safety and health education, work environment monitoring, health examination, health management record, and personal protective equipment (PPE) for plant construction workers. The safety training rate for plant construction workers was reached high at 91%, The training was mostly consisted of safety accident related things, but training on hazardous materials was found to be insufficient. Workplace monitoring results showed that the compliance rate for work environment for irregular construction workers was 54% and workplace monitoring during turnaround (TA) period with high risk of exposure to hazardous agents has not been implemented. While 61.4% of irregular workers received the general health examination but only 36.8% received the special health examination. The special health examination was found to be conducted only upon welders from 2-3 years ago. The issue of health management record upon irregular construction workers was not being implemented. In case of PPE, basic safety protective equipments such as safety shoes, safety belt, safety helmet were being supplied well while the supply rate of respirator for organic vapor was relatively low at 40%. Based on this study, two suggestions to maximize the utilization of the current safety and health program were made while boosting its effectiveness in protecting workers' health. First, the role of owners (petrochemical plant) related to safety and health should be strengthened. Second, in consideration of the characteristics of construction workers who usually engage in short term employment and frequent movement, community based health management organization is suggested that can overcome such structural problem and carry out the implementation of health examination and sustained health management.

• Journal of the Korean association of regional geographers
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• v.14 no.4
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• pp.290-308
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• 2008

The industrial development of Goryeong County was started by the operation of the Ssangrym Agro￢industrial complex in the 1980s. As of 2m3, there are 6 industrial complexes in Goryeong County which account for 80 percent of total employment and 67 percent of total production outPuts in local manufacturing. The local manufacturing industries grew steadily before the 1997 financial crisis which resulted in industrial decline and have shown again a growing tendency since 2000. In this period of growth, manufacturing outPuts are increased and the industrial structure are improved, while employment and value added are in stagnation. The major industrial agglomerations are based in Gaejin-Myun, Dasan-Myun and Ssangrym-Myun, all of which are those in which the agro-industrial complex is operated. More than half of local manufacturing finns are those which came to move in from other regions, looking for cheap labour forces, agglomeration of the related finns and the easy accessibility to transport and communication. However, such local advantages are increasingly losing due to the shortage of labour forces and the lack of industrial networks. Some policy agendas can be suggested as follows. First of all, industrial policy should attempt links with the building-up of the Daegu Technopolis and the up-grading of the local industrial structure towards the knowledge-based industries. Secondly, the local government should make efforts to establish the innovation supporting system for local firms and the industrial and residential basis.

• Journal of agriculture & life science
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• v.43 no.6
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• pp.105-109
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• 2009

Kyungsan nursery complex which has a vast area for the production of various species of fruit tree stocks is in a high demand of virus-free saplings. Apple tree stocks, the most important products, urgently need more rapid and reliable viral diagnosis. In this study, a bead beater was tested because of convenience in dealing with large number of samples. Also, industrial glass bead abrasive (0.4 mm in diameter) at very low cost was used in a disposable way. For bead beater-aided RNA extraction from apple stem tissues, the guanidine thiocyanate method was confirmed to be very reliable. Silca membrane filter tube in connection to vacuum filtering device was strongly suggested for simplifying RNA capture and washing steps. Apple virus detection was confirmed by RT-PCR.

• Journal of Microbiology and Biotechnology
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• v.28 no.9
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• pp.1547-1553
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• 2018

Hyaluronidases are a family of enzymes that catalyse the breakdown of hyaluronic acid, which is abundant in the extracellular matrix and cumulus oocyte complex. To investigate the activity of recombinant bovine sperm hyaluronidase 1 (SPAM1) and determine the effect of the Asn-X-Ser/Thr motif on its activity, the bovine SPAM1 open reading frame was cloned into the mammalian expression vector pCXN2 and then transfected to the HEK293 cell line. Expression of recombinant bovine hyaluronidase was estimated using a hyaluronidase activity assay with gel electrophoresis. Recombinant hyaluronidase could resolve highly polymeric hyaluronic acid and also caused dispersal of the cumulus cell layer. Comparative analysis with respect to enzyme activity was carried out for the glycosylated and deglycosylated bovine sperm hyaluronidase by N-glycosidase F treatment. Finally, mutagenesis analysis revealed that among the five potential N-linked glycosylation sites, only three contributed to significant inhibition of hyaluronic activity. Recombinant bovine SPAM1 has hyaluronan degradation and cumulus oocyte complex dispersion ability, and the N-linked oligosaccharides are important for enzyme activity, providing a foundation for the commercialization of hyaluronidase.