• 한국측량학회지
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• 제38권6호
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• pp.553-559
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• 2020

노후화된 지하시설물의 손상이 주요 원인이 되어 발생하는 도심지 지반침하를 예방하기 위해 지하시설물의 체계적 관리를 위해 지하공간 통합지도가 제작되고 있다. 그러나, 지하공간 통합지도를 갱신하는 과정에 갱신되지 않은 지하시설물 객체가 포함되어 갱신 시간을 지연시키는 문제가 있다. 본 논문에서는 지하시설물의 중심점을 기반으로 지하공간 통합지도의 갱신 과정에 필요한 갱신된 객체만을 선별함으로써 통합지도의 갱신 시간을 단축하는 방법에 대해 제안하였다. 중심점 비교를 통해 검색 대상을 대폭 감소시켜 검색 속도를 단축하고, 동일 객체 여부는 두 객체의 실제 위치를 이용한 거리를 계산하여 판정하였다. 제안된 방법은 데이터의 수량이 많을수록 빠른 성능을 나타내고, 기존의 방법에 비해 약 4배 정도 빠르게 갱신된 객체를 지하공간 통합지도에 반영할 수 있다.

• 한국정보통신학회논문지
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• 제24권9호
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• pp.1231-1240
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• 2020

상수도 배관은 땅속에 매설되어 있어서 배관의 노후화에 따른 누수를 맨눈으로 탐지하기가 불가능하며, 누수음을 감지함으로써 배관의 누수를 탐지하는 기술이 주로 사용된다. 본 논문에서는 상수도 배관의 양단에 두 개의 가속도계를 부착·취득한 데이터 간의 도달 시간 차이를 계산하여 누수 지점을 탐지하는 알고리즘을 개발하였다. 배관의 누수 시험은 17.2m의 배관에 4.3m, 8.6m, 12.9m 지점에 밸브를 설치하고, 밸브의 개도율을 30%, 70%로 변경해 가면서 누수 지점을 분석하였으며, 밸브가 30%, 70%씩 개방된 정도의 배관 내 압력 강하에 대해서는 누수를 탐지할 수 있는 것으로 확인되었다. 초기 단계의 누수를 탐지하는 것이 매우 중요하며, 본 연구에서 적용한 알고리즘으로부터 초기의 누수 지점의 탐지가 가능할 것으로 판단된다.

• Safety and Health at Work
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• 제11권4호
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• pp.405-417
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• 2020

Background: Electrical socket outlets are used continuously until a failure occurs because they have no indication of manufacturing date or exchange specifications. For this reason, 659 electrical fires related to electrical socket outlets broke out in the Republic of Korea at 2018 only, an increase year on year. To reduce electrical fires from electrical socket outlets, it is necessary to perform an accelerated test and analyze the thermal, insulation resistance, and material properties of electrical socket outlets by installation years. Methods: Thermal characteristics were investigated by measured the temperature increase of electrical socket outlets classified according to year with variation of the current level. Insulation resistance characteristics was measured according to temperature for an electrical socket outlets by their years of use. Finally, to investigate the thermal and insulation resistance characteristics in relation to outlet aging, this study analyzed electrical socket outlets' conductor surface and content, insulator weight, and thermal deformation temperature. Results: Analysis showed, regarding the thermal characteristics, that electrical socket outlet temperature rose when the current value increased. Moreover, the longer the time that had elapsed since an accelerated test and installation, the higher the electrical socket outlet temperature was. With respect to the insulation resistance properties, the accelerated test (30 years) showed that insulation resistance decreased from 110 ℃. In relation to the installation year (30 years), insulation resistance decreased from 70 ℃, which is as much as 40 ℃ lower than the result found by the accelerated test. Regarding the material properties, the longer the elapsed time since installation, the rougher the surface of conductor contact point was, and cracks increased. Conclusion: The 30-year-old electrical socket outlet exceeded the allowable temperature which is 65 ℃ of the electrical contacts at 10 A, and the insulation resistance began to decrease at 70 ℃. It is necessary to manage electrical socket outlets that have been installed for a long time.

• Structural Engineering and Mechanics
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• 제83권5호
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• pp.693-707
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• 2022

Bonded joints have proven their performance against conventional joining processes such as welding, riveting and bolting. The single-lap joint is the most widely used to characterize adhesive joints in tensile-shear loadings. However, the high stress concentrations in the adhesive joint due to the non-linearity of the applied loads generate a bending moment in the joint, resulting in high stresses at the adhesive edges. Geometric optimization of the bonded joint to reduce this high stress concentration prompted various researchers to perform geometric modifications of the adhesive and adherends at their free edges. Modifying both edges of the adhesive (spew) and the adherends (bevel) has proven to be an effective solution to reduce stresses at both edges and improve stress transfer at the inner part of the adhesive layer. The majority of research aimed at improving the geometry of the plate and adhesive edges has not considered the effect of temperature and water absorption in evaluating the strength of the joint. The objective of this work is to analyze, by the finite element method, the stress distribution in an adhesive joint between two 2024-T3 aluminum plates. The effects of the adhesive fillet and adherend bevel on the bonded joint stresses were taken into account. On the other hand, degradation of the mechanical properties of the adhesive following its exposure to moisture and temperature was found. The results clearly showed that the modification of the edges of the adhesive and of the bonding agent have an important role in the durability of the bond. Although the modification of the adhesive and bonding edges significantly improves the joint strength, the simultaneous exposure of the joint to temperature and moisture generates high stress concentrations in the adhesive joint that, in most cases, can easily reach the failure point of the material even at low applied stresses.

• 한국방재안전학회논문집
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• 제15권3호
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• pp.1-14
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• 2022

최근 기후변화와 하천 제방의 노후화로 인해 수재해 위험이 가중되고 있으나 기존의 재래적인 하천 제방의 점검은 많은 인력과 예산 소모로 많은 한계점들이 존재하다. 이에 따라 효과적인 홍수 대응을 위해 새로운 모니터링과 예/경보 시스템 구축이 필요한 상황이다. 본 연구는 인공위성(Sentinel-1)을 이용한 하천 제방 변위 산출, 수문학적 요인과의 관계 분석 항목들을 결합한 하천 제방 건강상태 모니터링 방법을 제안한다. 본 연구에서 산정한 변동성 지수를 계산하여 4등급으로 구분하였고, 토양 수분의 급증한 결과를 토대로 제방 붕괴 구간이 변동성이 급증한 취약지점 상태로 판단하였다. 향후에는 원격 기술과 분석 항목들을 결합한 포렌식 기법을 통해 기존 제방관리 시스템의 고도화가 가능할 것으로 기대한다.

• 대한지역사회영양학회지
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• 제28권4호
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• pp.317-328
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• 2023

Objectives: This study aimed to investigate the correlation between adolescents' dietary safety management competency, value recognition, efficacy, and competency of convergence using the dietary area (CUDA). Methods: Data were collected from 480 middle and high school students in Daegu, Gyeongbuk and Seoul, Gyeonggi using a self-administered five-point Likert scale questionnaire from May to July 2021. A questionnaire was used to investigate dietary safety management competency, awareness of convergence, recognition of the benefits, efficacy, and competency of CUDA. Results: We conducted factor, reliability, correlation, and regression analyses using SPSS 25. The average scores for each factor were: dietary significance (3.68); dietary safety management knowledge (3.34); food selection and cooking (3.72); nutrition management (3.38); weight management (3.28); risk dietary management (3.13); CUDA interest (2.98); convergence necessity (3.50); benefits in specialized areas (3.31); benefits in everyday life (3.48); efficacy of science and technology convergence (3.35); convergence efficacy with humanities, social science, and arts (3.31); and CUDA competency (3.41). The score for interest in CUDA was lower than that for the recognition of CUDA benefits. Significant positive correlations were observed between all factors except between risk dietary management and both nutrition and weight management (P < 0.01). Interest in CUDA and recognition of the need for convergence exhibited a positive and significant effect on all factors of the perception of CUDA benefits and efficacy. The subgroup factors of dietary safety management competency and the recognition of CUDA had a positive effect on the CUDA competency (P < 0.001, R²= 0.58). Conclusions: Strengthening dietary safety management competency and increasing the awareness of CUDA can enhance adolescents' convergence competency. Therefore, CUDA and targeted education must be actively promoted among adolescents.

• Medical Lasers
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• 제8권1호
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• pp.13-18
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• 2019

Background and Objectives High-intensity focused ultrasound (HIFU) can produce small zones of thermal damage. A HIFU procedure is non-invasive and it can achieve rejuvenation of facial skin. Fractional CO₂ laser resurfacing delivers thermal damage to the pixilated columnar zone of the skin and so evoke collagen remodeling, the same as HIFU. In many cases, the patients who want rejuvenation with HIFU are also good candidates for cutaneous photorejuvenation such as can be accomplished via fractional CO₂ resurfacing. If patients are treated in a single session by remodeling both the superficial and deep compartments of skin by using both modalities, then improvement in rhytides and tightening of sagging skin will optimize the aesthetic result. Materials and Methods Between May 2014 and January 2018, a total of 44 patients were treated with combination HIFU and fractional CO₂ laser resurfacing according to our protocol. First, the HIFU was applied to the entire face with an average of 300 treatment lines. Immediately after HIFU treatment, the ultrasound gel was washed off and then fractional CO₂ laser resurfacing was performed. We evaluated the patients using 4-point grading scales. The clinician examined the skin for evidence of complications after the completion of treatment. Results All the patients' skin quality showed improvement. Further. the clinical results after duel modality treatment were substantially better than that after the use of either modality alone. The recovery times and the incidence of adverse events when quickly and consecutively performing both treatments were similar as compared to those with employing stepwise treatment. We encountered no complications whatsoever. Conclusion When compared with stepwise therapy, combination therapy with HIFU and fractional CO₂ resurfacing offers better, safer and more effective clinical results. Thus, for targeting multiple layers of aging facial skin, this combination therapy can be safely performed in a single treatment session.

• 실천공학교육논문지
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• 제15권3호
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• pp.771-777
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• 2023

본 연구는 우리나라 수산업의 회계정보시스템 교육과 활용에 대하여 연구하였다. 연구의 목적을 달성하기 위하여 수산업체를 대상으로 설문을 조사하였다. 그리고 설문 내용을 다양한 통계 방법을 적용하여 분석하였다. 연구의 시사점은 다음과 같다. 첫째, 오늘날 정보화시대의 수산업 경영은 회계정보시스템을 통한 효율적인 경영기법의 활용이 필요하다고 판단된다. 둘째, 수산업체는 정보시스템을 적극적으로 경영에 도입하여 자금의 운용과 조달 그리고 경영비 관리, 경영분석 등을 활용하여 효율성을 높이는 것이 중요한 과제라 사료된다. 끝으로, 수산업체는 정보시스템을 통한 회계관리와 원가계산을 실시하여 합리적인 의사결정에 활용할 중요한 시점이라 판단된다.

• Computers and Concrete
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• 제33권5호
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• pp.595-603
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• 2024

In the construction industry, there has been a surge in the implementation of high-tech equipment in recent years. Various technologies are being considered as potential solutions for future construction projects. Building information modeling (BIM), which utilizes advanced equipment, is a promising solution among these technologies. The need for safety inspection has also increased with the aging structures. Nevertheless, traditional safety inspection technology falls short of meeting this demand as it heavily relies on the subjective opinions of workers. This inadequacy highlights the need for advancements in existing maintenance technology. Research on building safety inspection using 3D laser scanners has notably increased. Laser scanners that use light detection and ranging (LiDAR) can quickly and accurately acquire producing information, which can be realized through reverse engineering by modeling point cloud data. This study introduces an innovative evaluation system for building safety using a 3D laser scanner. The system was used to assess the safety of an existing three-story building by implementing a reverse engineering technique. The 3D digital data are obtained from the scanner to detect defects and deflections in and outside the building and to create an as-built BIM. Subsequently, the as-built structural model of the building was generated using the reverse engineering approach and used for structural analysis. The acquired information, including deformations and dimensions, is compared with the expected values to evaluate the effectiveness of the proposed technique.

• The Korean Journal of Pain
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• 제37권1호
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• pp.51-58
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• 2024

Background: The rise in national health care costs has emerged as a global problem given the ever-aging population and rapid development of medical technology. The utilization of interventional pain management has, similarly, shown a continued rise worldwide. This study evaluates the differences in the medical costs in the field of interventional pain treatment (IPT) between two countries: Korea and Japan. Methods: Korean medical insurance costs for 2019 related to pain management focused on IPT were compared to those of Japan. Purchasing power parity (PPP) was used to adjust the exchange rate differences and to compare prices in consideration of the respective societies' economic power. Results: The cost of trigger point injections in Japan was 1.06 times higher than that of Korea, whereas the perineural and intraarticular injection prices were lower in Japan. The cost of epidural blocks was higher in Japan compared to Korea in both cervical/thoracic and lumbar regions. As for blocks of peripheral branches of spinal nerves, the cost of scapular nerve blocks in Japan was lower than that in Korea, given a PPP ratio 0.09. For nerve blocks in which fluoroscopy guidance is mandatory, the costs of epidurography in Japan were greater than those in Korea, given a PPP ratio 1.04. Conclusions: This is the first comparative study focusing on the medical costs related to IPT between Korea and Japan, which reveals that the costs differed along various categories. Further comparisons reflecting more diverse countries and socio-economic aspects will be required.