• Computers and Concrete
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• v.27 no.3
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• pp.283-295
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• 2021

Existing meso-scale models of concrete need to refine the mesh grids of aggregate and cement mortar, which may greatly reduce the computational efficiency. To overcome this problem, a novel meso-scale modeling strategy, which is based on rigid body spring method and Voronoi diagram, is proposed in this study to establish the meso-scale model of concrete. Firstly, establish numerical aggregate models according to user-defined programs. Circle aggregates are adopted due to their high efficiency in generation and packing process, and the grading of aggregate are determined according to the distribution curve proposed by Full and Thompson; Secondly, extract the centroids of aggregates, and then develop the Voronoi diagram in which aggregate centroids are defined as initial scatters; Finally, establish the rigid body spring model for concrete based on the Voronoi diagram. Aggregates are represented by rigid blocks, and assumed to be unbreakable. Cement mortar is concentrated into the interface between adjacent blocks and represented by two uniform springs. The number of grids is consistent with that of aggregates in specimens, and no mesh-refinement of aggregates and cement mortar is required. The accuracy and efficiency of the proposed modeling strategy are firstly identified by comparing the numerical results with the experimental ones, and then the applicability of the proposed strategy with different volume percentage occupied by aggregates is investigated.

• Journal of Korean Neurosurgical Society
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• v.66 no.3
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• pp.324-331
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• 2023

Objective : We aimed to analyze the effectiveness of external neurolysis on the common peroneal nerve (CPN) in patients with posture-induced compressive peroneal neuropathy (PICPNe). Further, we aimed to examine the utility of magnetic resonance imaging (MRI) in assessing the severity of denervation status and predicting the postoperative prognosis. Methods : We included 13 patients (eight males and five females) with foot drop who underwent CPN decompression between 2018 and 2020. We designed a grading system for assessing the postoperative functional outcome. Additionally, we performed MRI to evaluate the denervation status of the affected musculature and its effect on postoperative recovery. Results : The median time to surgery was 3 months. The median preoperative ankle dorsiflexion and eversion grades were both 3, while the average functional grade was 1. Posterior crural intermuscular septum was the most common cause of nerve compression, followed by deep tendinous fascia and anterior crural intermuscular septum. There was a significant postoperative improvement in the median postoperative ankle dorsiflexion and eversion grades and average postoperative functional (4, 5, and 2.38, respectively). Preoperative ankle eversion was significantly correlated with denervation status. Additionally, the devernation status on MRI was positively correlated with the outcome favorability. However, denervation atrophy led to a less favorable outcome. Conclusion : Among patients with intractable PICPNe despite conservative management, surgical intervention could clinically improve motor function and functional ability. Additionally, MRI examination of the affected muscle could help diagnose CPNe and assess the postoperative prognosis.

• Journal of the Korea Safety Management & Science
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• v.25 no.4
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• pp.57-65
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• 2023

The public safety management guidelines were introduced in 2019 and continue to be dedicated to advancing comprehensive measures for public safety management, with a primary focus on prioritizing the safety and well-being of the public within governmental institutions. To achieve this goal, our previous study developed a establishment procedure of risk assessment-based safety inspection system for public institutions that order construction projects and applied it to highway construction projects to evaluate its effectiveness. To enhance the practicality of the establishment procedure, it is essential to collect and analyze feedback from stakeholders regarding its performance and suitability. This study conducted a survey involving 200 participants who had experience with the establishment procedure, and performed statistical analyses to evaluate its performance and applicability. The survey results indicated that the participants reported a high level of satisfaction (scoring 4 and above on a 5-point Likert scale) in several areas: specialization of safety inspection items for different types of work (with a satisfaction rate of 65%), the evaluation process for safety ratings (64.5%), and their willingness to recommend the procedure to other institutions (75.5%). In the factor analysis with Varimax rotation, two factors emerged: (1) a specialization factor related to safety inspection items, and (2) a grading factor associated with safety evaluation results. Regression analyses of these factors unveiled significant positive relationships with improvements in safety and health performance, including the prevention of fatal accidents, heightened safety responsibility, and raised safety inspection standards. The establishment procedure of safety inspection system developed in our previous study can play a crucial role in reducing accidents resulting in fatalities and injuries at construction sites, ultimately contributing to a safer working environment for all involved parties.

• Clinical Endoscopy
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• v.57 no.2
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• pp.141-157
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• 2024

Antithrombotic agents, including antiplatelet agents and anticoagulants, are widely used in Korea because of the increasing incidence of cardiocerebrovascular disease and the aging population. The management of patients using antithrombotic agents during endoscopic procedures is an important clinical challenge. The clinical practice guidelines for this issue, developed by the Korean Society of Gastrointestinal Endoscopy, were published in 2020. However, new evidence on the use of dual antiplatelet therapy and direct anticoagulant management has emerged, and revised guidelines have been issued in the United States and Europe. Accordingly, the previous guidelines were revised. Cardiologists were part of the group that developed the guideline, and the recommendations went through a consensus-reaching process among international experts. This guideline presents 14 recommendations made based on the Grading of Recommendations, Assessment, Development, and Evaluation methodology and was reviewed by multidisciplinary experts. These guidelines provide useful information that can assist endoscopists in the management of patients receiving antithrombotic agents who require diagnostic and elective therapeutic endoscopy. It will be revised as necessary to cover changes in technology, evidence, or other aspects of clinical practice.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.2
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• pp.82-89
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• 2009

According to the great city development and the rapid growth of redevelopment project, waste concrete emission has been increased. Waste concrete powder is one of the by-product originated from the recycling of the waste concrete. The more making high quality recycled aggregate to use aggregate for concrete, the more waste concrete powder is producted relatively. Therefore, to realize the total recycling of waste concrete, development of recycling technology for waste concrete powder need very much. This technical note present the discharged process and the various properties of waste concrete powder. As the results, on the average, the maximum particle-size of waste concrete powder is less than $600{\mu}m$, and oven-dry density is less than $2.5g/cm^3$. And waste concrete powder contains more than 50% of $SiO_2$, 30% of CaO and 10% of $Al_2O_3$. Thus qualities of waste concrete powder is lower than those of high quality raw material for concrete. However, if it is processed by grading to the purpose, it will be used as resource of raw materials for construction field.

• Journal of Korean Society of Forest Science
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• v.106 no.1
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• pp.70-76
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• 2017

Among the forest road pavement methods, the majority of current constructions utilize concrete pavements but it has disadvantages as follows: many cracked concrete pavements generated by the erosion of underlying soil layers, could not be used as forest roads in steep slope during winter, and cement contains hazardous chemicals (hexavalent chromium, etc.). In order to supplement the limitations of the use of concrete pavement, this study was conducted to investigate the operation process and cost, the strength and compaction of the experimental forest road pavement(85 m) utilizing eco-friendly solidification material at Goryeong-gun, Gyeongsangbuk-do. The work elements of experimental forest road paving were classified into: preparation, Roadbed excavation, Roadbed grading, subgrade compaction, form work, collection and selection of site soil, mixing site soil and eco-friendly solidification material, paving by eco-friendly solidification material, compaction by vibrating roller and curing. The result of economic analysis using construction cost shows that for concrete costs total to $38,681won/m^3$ while for the eco-friendly paving material it is $38,245won/m^3$. Thus the construction costs for concrete and the eco-friendly paving material are similar. And the results of the Schmidt Hammer test for strength analysis by curing period are 10.5-13.5 MPa for 7 days, 18.1-22.7 MPa for 14 days, and 20.8-23.0 MPa for 28 days.

• Korean Security Journal
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• no.40
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• pp.175-207
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• 2014

This paper focuses on the study of a development direction of the industrial security Expert system. First of all, in order to manage Industrial security system, we need to have law, criminology, business and engineering professionals as well as IT experts, which are the multi-dimensional convergence professionals. Secondly, industrial organizations need to have workforce who can perform security strategy; security plan; security training; security services; or security system management and operations. Industrial security certification system can contribute to cultivate above mentioned professional workforce. Currently Industrial Security Expert(ISE) is a private qualification. However, the author argued that it have to be changed to national qualification. In addition, it is necessary that the system should be given credibility with verifying the personnel whether they are proper or not in the their field. In terms of quality innovation, it is also necessary that distinguish the levels of utilization of rating system of the industrial security coordinator through a long-term examination. With respect to grading criteria, we could consider the requirements as following: whether they must hold the degree of the industrial security-related areas of undergraduate or postgraduate (or to be); what or how many industrial security-related courses they should complete through a credit bank system. If the plan of completing certain industrial security-related credits simply through the credit bank system, without establishing a new industrial security-related department, has established, then industrial security study would be spreaded and advanced. For private certification holders, the problem of the qualification succeeding process is important matter. Additionally, it is necessary to introduce the certifying system of ISMS(Industrial Security Management System) which is a specialized system for protecting industrial technology. To sum up, when the industrial security management system links the industrial security management certification, industrial security would realize in the companies and research institutions dealing with national key technology. Then, a group synergy effect would occurs.

• Korean Journal of Head & Neck Oncology
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• v.12 no.1
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• pp.16-21
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• 1996

Lymphomatoid granulomatosis, polymorphic reticulosis, midline malignant reticulosis, or lethal midline granuloma have similar histologic features of an angiocentric and angiodestructive lymphoreticular proliferation representing the same nosologic entity. The term 'angiocentric immunoproliferative lesion' (AIL) was proposed by Jaffe, Costa, and Martin. The malignant potential of AILs is originally uncertain, but the facts that AILs have a relatively short survival, and most of them usually progress to an overt malignant lymphoma and survival is inversely proportional to the large, atypical lymphoreticular cells suggest that AILs are malignane. We experienced 17 AILs in nose during 16-year period and retrogradely analized them to recognize the problems in the diagnosis and to establish the further therapeutic strategies. The results were as follows; Twelve of total 17 patients who had diagnosed as histologic grade 1 and 2 had received radiation therapy as an initial treatment and the complete response rate was 91.7%(11/12), but 6 out of 11 had local recurrence and 5 had progress to overt maligant lymphoma within 2years. Three patients with the histologic grade 3 and 2 with unclear histologic grade had received CHOP chemotherapy and there was 1 case with complete response. Two patients with unclear histologic grade had been proved to be malignant histiocytosis by bone marrow biopsy during the clinical course. The overall duration of survival was 2 - 119 months and the 5-year survival rate was 71.9%. And the achievement of initial complete response was the most important prognostic factor of overall survival(P=0.006). Our results suggest that the treatment strategy according to the histologic grading scheme is efficient and more aggressive combination chemotherapy may be necessary to achieve complete response in patients with histologic grade III and II, because most of them progress to overt malignant lymphoma during its process.

• Korean Journal of Cognitive Science
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• v.26 no.2
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• pp.147-165
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• 2015

Through short-answer questions, we can reflect the depth of students' understanding and higher-order thinking skills. Scoring for short-answer questions may take long time and may be an issue on consistency of grading. To alleviate such the suffering, automated scoring systems are widely used in Europe and America, but are in the initial stage in research in Korea. In this paper, we propose a semi-automatic scoring system for short Korean free-text responses using semi-supervised learning. First of all, based on the similarity score between students' answers and model answers, the proposed system grades students' answers and the scored answers with high reliability have been included in the model answers through the thorough test. This process repeats until all answers are scored. The proposed system is used experimentally in Korean and social studies in Nationwide Scholastic Achievement Test. We have confirmed that the processing time and the consistency of grades are promisingly improved. Using the system, various assessment methods have got to be developed and comparative studies need to be performed before applying to school fields.

• Journal of Preventive Medicine and Public Health
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• v.42 no.4
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• pp.237-242
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• 2009

Objectives : The incidence of zoonoses in Korea has increased recently. However, the study of high risk groups for zoonoses has not been conducted to date in Korea. Thus, we did this study to obtain data on brucellosis among slaughterhouse workers in Korea. Methods : We evaluated the structure of slaughterhouses and the process of slaughtering by reviewing the relevant literature and doing field studies. We visited 73 slaughterhouses and 62 residual products handle houses across the country. In addition, we conducted a questionnaire survey of the work activities, and obtained blood samples in order to determine the seroprevalence and risk factors of brucellosis. The titers of brucellosis antibodies were measured using the standard tube agglutination test SAT). We diagnosed subjects as seropositive for Brucellosis if the titers were more than 1:160. The data collected was evaluated using SPSS ver. 17.0. Results : We included 1,503 subjects and obtained 1,482 blood samples among them: 849 workers involved in slaughtering, 351 handlers of residual products, 190 inspectors and their assistants, and 92 grading testers and their assistants. The seroprevalence of brucellosis among the slaughterhouse workers was 0.8% (95% CI=0.4-1.5). Broken down, the seroprevalence of brucellosis among the workers involved in slaughtering was 0.7% (95% CI=0.3-1.6), the handlers of residual products was 1.7% (95% CI=0.7-3.9) respectively. Risk factors for contracting brucellosis among slaughterhouse workers were being splashed with cattle blood around the mouth, cattle secretions around the body and not putting on protective apron while at work. Conclusions : An educational program is needed for high risk groups on zoonoses about the prevention of infection. Thus, effective working guidelines for workers who participate in the slaughter of animals must be developed in order to protect them from zoonoses.