• Journal of Cadastre & Land InformatiX
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• v.52 no.2
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• pp.53-65
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• 2022

According to the advancement of the GNSS satellite positioning system, the module of hardware and operation software reflecting accuracy and economical efficiency is implemented in the user sector including the multi-channel GNSS receiver, the multi-frequency external antenna and the mobile app (App) base public positioning analysis software etc., and the multichannel GNSS RTK positioning of the active configuration method (DIY, Do it yourself) is possible according to the purpose of user. Especially, as the infrastructure of multi-GNSS satellite is expanded and the potential of expansion of utilization according to various modules is highlighted, interest in the utilization of multi-channel low-cost GNSS receiver module is gradually increasing. The purpose of this study is to review the multi-channel low-cost GNSS receivers that are appearing in the mass market in various forms and to analyze the utilization plan of the "address information facility investigation project" of the Ministry of Public Administration and Security by constructing the multi-channel low-cost GNSS positioning module based RTK survey system (hereinafter referred to as "multi-channel GNSS RTK module positioning system"). For this purpose, we constructed a low-cost "multi-channel GNSS RTK module positioning system" by combining related modules such as U-blox's F9P chipset, antenna, Ntrip transmission of GNSS observation data and RTK positioning analysis app through smartphone. Kinematic positioning was performed for circular trajectories, and static positioning was performed for address information facilities. The results of comparative analysis with the Static positioning performance of the geodetic receivers were obtained with 5 fixed points in the experimental site, and the good static surveying performance was obtained with the standard deviation of average ±1.2cm. In addition, the results of the test point for the outline of the circular structure in the orthogonal image composed of the drone image analysis and the Kinematic positioning trajectory of the low cost RTK GNSS receiver showed that the trajectory was very close to the standard deviation of average ±2.5cm. Especially, as a result of applying it to address information facilities, it was possible to verify the utility of spatial information construction at low cost compared to expensive commercial geodetic receivers, so it is expected that various utilization of "multi-channel GNSS RTK module positioning system"

• Journal of the Korean Orthopaedic Association
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• v.54 no.1
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• pp.45-51
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• 2019

Purpose: The clinical and radiological results of patients with type 3 talar neck fractures treated with the anteromedial approach using medial malleolar osteotomy and large distractor were analyzed retrospectively. Materials and Methods: From March 2009 to August 2016, 12 patients with a type 3 talar neck fracture, who underwent the anteromedial approach using a medial malleolar osteotomy and large distractor and who could be followed-up for more than 12 months after the operation, were examined. The patients were examined for the presence of Hawkins signs by anteroposterior and lateral radiographs and osteonecrosis by magnetic resonance imaging (MRI) on the postoperative 3 months. Subsequently, every 3 months, radiographic union was assessed by a simple radiograph and clinical symptoms. Twelve months postoperatively, posttraumatic arthritis was assessed and the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score was analyzed. Results: In 7 cases, osteonecrosis was found on MRI performed 3 months after surgery. On the other hand, at the 12 months follow-up, all of them obtained AOFAS scores of 83.86±4.53 without surgical treatment. Radiographic union was achieved in all cases. The mean union period was 5.3 months. In 10 cases, traumatic arthritis was found after the radiographical and clinical evaluation. In addition, all of them could carry on everyday life by conservative treatment. The AOFAS ankle-hindfoot score was measured to be 85.17 on average. Other complications included superficial wound infection in 2 cases. Conclusion: An anteromedial approach using a medial malleolar osteotomy and a large distractor in the surgical treatment of patients with type 3 talar neck fractures can achieve anatomical reduction of the displaced fragment without a lateral dissection. This is considered to be another good surgical option.

• Journal of the Korean Orthopaedic Association
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• v.54 no.4
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• pp.327-335
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• 2019

Purpose: To investigate the radiological efficacy of polymethylmethacrylate (PMMA) augmentation of pedicle screw operation in osteoporotic vertebral compression fractures (OVCF) patients. Materials and Methods: Twenty OVCF patients, who underwent only posterior fusion using pedicle screws with PMMA augmentation, were included in the study. The mean follow-up period was 15.6 months. The demographic data, bone mineral density (BMD), fusion segments, number of pedicle screws, and amount of PMMA were reviewed as medical records. To analyze the radiological outcomes, the radiologic parameters were measured as the time serial follow-up (preoperation, immediately postoperation, postoperation 6 weeks, 3, 6 months, and 1 year follow-up). Results: A total of 20 patients were examined (16 females [80.0%]; mean age, 69.1±8.9 years). The average BMD was -2.5±0.9 g/cm². The average cement volume per vertebral body was 6.3 ml. The mean preoperative Cobb angle of focal kyphosis was 32.7°±7.0° and was improved significantly to 8.7°±6.9° postoperatively (p<0.001), with maintenance of the correction at the serial follow-up, postoperatively. The Cobb angle of instrumented kyphosis, wedge angle, and sagittal index showed similar patterns. In addition, the anterior part of fractured vertebral body height averaged 11.0±5.0 mm and was improved to 18.5±5.7 mm postoperatively (p=0.006), with maintenance of the improvement at the 3-month, 6-month, and 1-year follow-up. Conclusion: The reinforcement of pedicle screws using PMMA augmentation may be a feasible surgical technique for OVCF. Moreover, it appears to be appropriate for improving the focal thoracolumbar/lumbar kyphosis and is maintained well after surgery.

• Journal of the Korean Orthopaedic Association
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• v.54 no.4
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• pp.336-342
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• 2019

Purpose: To examine the relationship between the progression of a kyphotic deformity and the magnetic resonance imaging (MRI) findings in conservatively treated osteoporotic thoracolumbar compression fracture patients. Materials and Methods: This study categorized the patients who underwent conservative treatment among those patients who underwent treatment under the suspicion of a thoracolumbar compression fracture from January 2007 to March 2016. Among them, this retrospective study included eighty-nine patients with osteoporosis and osteopenia with a bone density of less than -2.0 and single vertebral body fracture. This study examined the MRI of anterior longitudinal ligament or posterior longitudinal ligament injury, superior or inferior endplate disruption, superior of inferior intravertebral disc injury, the presence of low signal intensity on T2-weighted images, and bone edema of intravertebral bodies in fractured intravertebral bodies. Results: In cases where the superior endplate was disrupted or the level of bone edema of the intravertebral bodies was high, the kyphotic angle, wedge angle, and anterior vertebral compression showed remarkably progression. In the case of damage to the anterior longitudinal ligament or the superior disc, only the kyphotic angle was markedly prominent. On the T2-weighted images, low signal intensity lesions showed a high wedge angle and high anterior vertebral compression. On the other hand, there were no significant correlations among the posterior longitudinal ligament injury, inferior endplate disruption, inferior disc injury, and the progression of kyphotic deformity and vertebral compression. The risk factors that increase the kyphotic angle by more than 5° include the presence of injuries to the anterior longitudinal ligament, superior endplate disruption, and superior disc injury, and the risk factors were 21.3, 5.1, and 8.5 times higher than those of the uninjured case, and the risk differed according to the level of bone edema. Conclusion: An osteoporotic thoracolumbar compression fracture in osteoporotic or osteopenic patients, anterior longitudinal ligament injury, superior endplate and intravertebral disc injury, and high level of edema in the MRI were critical factors that increases the risk of kyphotic deformity.

• Korean small business review
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• v.41 no.4
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• pp.1-36
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• 2019

The purpose of this study is to identify the relationships among purposes and contents of smart factory building and continuous utilization of smart factory. Specifically, this study identifies two types of purposes of smart factory building as follows: (1) improving productivity, (2) increasing flexibility. In this study, three aspects of smart factory building contents were suggested like this: (1) automation area (facility automation vs. work automation), (2) big data system focus (radical transformation vs. incremental improvement), and (3) value chain integration area (internal value chain integration vs. external value chain integration). In addition, we looked at how firm size moderates the purposes - contents - continuous utilization of smart factory relationship. A questionnaire survey was conducted on 151 manufacturing companies. More specifically, out of 151 companies, 100 are small-and-medium-sized enterprises and 51 large-sized enterprises. All questionnaires were targeted at companies with Smart Factory level above level 2. The analysis results of this study using Smart PLS statistical programs are as follows. First, the purposes of smart factory building including increasing productivity and flexibility had positive impacts on all of the contents of smart factory building. Second, all of smart factory building contents had positive impacts on the continuous use of smart factory except big data system for incremental improvement of manufacturing process. Third, the impacts of smart factory building purposes implementation on smart factory building contents varied depending on whether the purpose is productivity improvement or flexibility. Fourth, it was founded that firm size moderated the relationships of purposes - contents - continuous utilization of smart factory in such a way that large-sized firms tend to empathize the link between flexibility and smart factory building contents for continuous use of smart factory, while small-and-medium-sized-firms emphasizing the link between productivity and smart factory building contents. Most of the previous studies have focused on presenting current smart factory deployment cases. However, it is believed that this research has made a theoretical contribution in this field in that it established and verified a research model for the smart factory building strategy. Based on the findings from a working-level perspective, corporate practitioners also need to have a different approach to smart factory building, which should be emphasized depending on whether their purpose of building smart factory is to increase productivity or flexibility. In particular, since the results of this study identify the moderating effect of firm size, it is deemed necessary for firms to implement a smart factory building strategy suitable for their firm size.

• Korean Journal of Remote Sensing
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• v.39 no.3
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• pp.325-338
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• 2023

Korean fir (Abies koreana Wilson) is one of the most important environmental indicator tree species for assessing climate change impacts on coniferous forests in the Korean Peninsula. However, due to the nature of alpine and subalpine regions, it is difficult to conduct regular field surveys of Korean fir, which is mainly distributed in regions with altitudes greater than 1,000 m. Therefore, this study analyzed the vegetation change trend of Korean fir using regularly observed remote sensing data. Specifically, normalized difference vegetation index (NDVI) from Moderate Resolution Imaging Spectroradiometer (MODIS), land surface temperature (LST), and precipitation data from Global Precipitation Measurement (GPM) Integrated Multi-satellitE Retrievalsfor GPM from September 2003 to 2020 for Hallasan and Jirisan were used to analyze vegetation changes and their association with environmental variables. We identified a decrease in NDVI in 2020 compared to 2003 for both sites. Based on the NDVI difference maps, areas for healthy vegetation and high mortality of Korean fir were selected. Long-term NDVI time-series analysis demonstrated that both Hallasan and Jirisan had a decrease in NDVI at the high mortality areas (Hallasan: -0.46, Jirisan: -0.43). Furthermore, when analyzing the long-term fluctuations of Korean fir vegetation through the Hodrick-Prescott filter-applied NDVI, LST, and precipitation, the NDVI difference between the Korean fir healthy vegetation and high mortality sitesincreased with the increasing LST and decreasing precipitation in Hallasan. Thissuggests that the increase in LST and the decrease in precipitation contribute to the decline of Korean fir in Hallasan. In contrast, Jirisan confirmed a long-term trend of declining NDVI in the areas of Korean fir mortality but did not find a significant correlation between the changes in NDVI and environmental variables (LST and precipitation). Further analyses of environmental factors, such as soil moisture, insolation, and wind that have been identified to be related to Korean fir habitats in previous studies should be conducted. This study demonstrated the feasibility of using satellite data for long-term monitoring of Korean fir ecosystems and investigating their changes in conjunction with environmental conditions. Thisstudy provided the potential forsatellite-based monitoring to improve our understanding of the ecology of Korean fir.

• Journal of Life Science
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• v.33 no.6
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• pp.498-505
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• 2023

Solanum tuberosum Linnaeus cv Hongyoung, which represents red potato, was developed in Korea. Hongyoung is known to have anti-oxidant, anti-inflammatory, anti-viral, and anti-tumor properties, but no research has been conducted on the growth inhibition and apoptosis effects of hongyoung in YD-10B oral cancer cells. In this study, the combined treatment of hongyoung ethanol extract (HEE) and cisplatin were examined to determine its ability to inhibit cancer cell growth, induce apoptosis, and inhibit matrix metalloproteinases (MMP)-2 and MMP-9 cancer metastasis. The cell viability was investigated using a 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H- tetrazolium monosodium salt (MTS) assay, and the ability to induce apoptosis was analyzed using an FACS analyzer. The mRNA expression and protein activity of MMP-2 and MMP-9 were measured via RT-PCR and zymography. The YD-10B oral cancer cells showed an increase in growth inhibition as the concentration of HEE increased. The combination of 200 µM cisplatin and 500 ㎍/ml HEE reduced the growth of the YD-10B oral cancer cells by more than 50% compared to cisplatin alone. When phorbol 12-myristate 13-acetate (PMA)-treated YD-10B oral cancer cells were co-treated with 200 µM cisplatin and 500 ㎍/ml HEE, both the mRNA expression and protein activity of the MMP-2 and MMP-9 decreased. In addition, the percentage of the sub-G1 phase, which indicates apoptosis ability, more than doubled when treated in combination with 200 µM cisplatin and 500 ㎍/ml HEE than when cisplatin alone was used. The results of this study therefore suggest the possibility of using a combination of HEE and cisplatin in the development of effective drugs to treat oral cancer.

• Resources Recycling
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• v.32 no.1
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• pp.50-59
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• 2023

The amount of dust generated during the dissolution of scrap in an electric arc furnace is approximately 1.5% of the scrap metal input, and it is primarily collected in a bag filter. Electric arc furnace dust primarily consists of zinc and ion. The processing of zinc starts with its conversion into pellet form by the addition of a carbon-based reducing agent(coke, anthracite) and limestone (C/S control). These pellets then undergo reduction, volatilization, and re-oxidation in rotary kiln or RHF reactor to recover crude zinc oxide (60%w/w). Next, iron is discharged from the electric arc furnace dust as a solid called Fe clinker (secondary by-product of the Fe-base). Several methods are then used to treat the Fe clinker, which vary depending on the country, including landfilling and recycling (e.g., subbase course material, aggregate for concrete, Fe-source for cement manufacturing). However, landfilling has several drawbacks, including environmental pollution due to leaching, high landfill costs, and wastage of iron resources. To improve Fe recovery in the clinker, we pulverized it into optimal -sized particles and employed specific gravity and magnetic force selection methods to isolate this metal. A carbon-based reducing agent and a binding material were added to the separated coarse powder (>10㎛) to prepare briquette clinker. A small amount (1-3%w/w) of the briquette clinker was charged with the scrap in an electric arc furnace to evaluate its feasibility as an additives (carbonaceous material, heat-generating material, and Fe source).

• Journal of The Korean Association For Science Education
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• v.43 no.3
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• pp.265-276
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• 2023

The purpose of this study was to develop a plan to ensure that students lacking basic science skills acquire the minimum needed science learning ability while completing the common curriculum. We surveyed 27 elementary and secondary science teachers with experience in research and teaching related to basic skills support to investigate their perceptions of the criteria for minimum achievement standards using Consensual Qualitative Research (CQR) and Analytic Hierarchy Process (AHP). The results indicated that the science teachers tended to describe low achievers as lacking science learning competency, accumulating a science learning deficit, and lacking prerequisite knowledge. However, there were some differences in the characteristics that the elementary and secondary teachers paid attention to in students with insufficient science and basic academic skills. Specifically, the secondary teachers demonstrated greater sensitivity towards low learning motivation and difficulties in using scientific symbols, whereas the elementary teachers were more sensitive towards students' attitudes towards science or lack of experience. Furthermore, it has been observed that the prioritization of items, categorized by school level, differs in terms of setting minimum achievement standards to ensure basic skill support. This implies the need to develop minimum achievement standards considering various variables based on the school level. As there are diverse opinions among science teachers, depending on their expertise, regarding the factors to be considered when developing these standards to guarantee science and basic skill support. Based on the findings of the study, policy support is required to enhance teachers' professionalism in developing students' basic skills while considering the individual context and diversity of low achievers. Additionally, it is crucial to establish a shared vision for students lacking basic skills to reduce the gap between national policy and the practices of science teachers in ensuring support for basic skills.

• Informatization Policy
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• v.30 no.2
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• pp.22-45
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• 2023

In research on the use of AI-based voice assistant services, problems related to the user's trust and privacy protection arising from the experience of service use are constantly being raised. The purpose of this study was to investigate empirically the effects of individual trust in AI and online privacy concerns on the continued use of AI-based voice assistants, specifically the impact of their interaction. In this study, question items were constructed based on previous studies, with an online survey conducted among 405 respondents. The effect of the user's trust in AI and privacy concerns on the adoption and continuous use intention of AI-based voice assistant services was analyzed using the Heckman selection model. As the main findings of the study, first, AI-based voice assistant service usage behavior was positively influenced by factors that promote technology acceptance, such as perceived usefulness, perceived ease of use, and social influence. Second, trust in AI had no statistically significant effect on AI-based voice assistant service usage behavior but had a positive effect on continuous use intention. Third, the privacy concern level was confirmed to have the effect of suppressing continuous use intention through interaction with trust in AI. These research results suggest the need to strengthen user experience through user opinion collection and action to improve trust in technology and alleviate users' concerns about privacy as governance for realizing digital government. When introducing artificial intelligence-based policy services, it is necessary to disclose transparently the scope of application of artificial intelligence technology through a public deliberation process, and the development of a system that can track and evaluate privacy issues ex-post and an algorithm that considers privacy protection is required.