• 한국컴퓨터정보학회논문지
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• 제28권1호
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• pp.93-101
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• 2023

이 논문은 영상 카메라를 이용하여 교통 객체를 인식하고자 하는 경우, 영상 내 객체 인식 정확도를 높이기 위해 소실점을 이용하여 객체에 대한 3D 바운딩 박스를 생성하는 방법이다. 최근 인공지능을 이용하여 교통 영상 카메라로 촬영된 차량을 검출하고자 하는 경우 이 3D 바운딩 박스 생성 알고리즘을 적용하고자 한다. 카메라 설치 각도와 카메라가 촬영한 영상의 방향성을 분석하여 종 방향 소실점(VP1)과 횡 방향 소실점(VP2)을 도출하고 이를 기반으로 분석 대상 동영상에서 이동하는 객체를 특정하게 된다. 이 알고리즘을 적용하면 감지된 객체의 위치, 종류, 크기 등 객체 정보 검출이 용이하고, 이를 자동차와 같은 이동류에 적용하는 경우 이를 트래킹하여 각 객체가 이동한 위치와 좌표, 이동속도 및 방향 등을 알 수 있다. 실제 도로에 적용한 결과 트래킹이 10% 향상되었으며 특히 음영지역(큰 차에 가려진 극히 적은 차량 부위)의 인식율과 트래킹이 100% 개선되는 등 교통 데이터 분석 정확성을 향상시킬 수 있었다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.379-395
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• 2021

For the complicated structural details in ships and offshore structures, the traditional hotspot stress approaches are known to be sensitive to the element variables of element topologies, sizes, and integration schemes. This motivated to develop a new approach for predicting reasonable hotspot stresses, which is less sensitive to the element variables and easy to be implemented the real marine structures. The three-point bending tests were conducted for the longitudinal attachments with the round and rectangular weld toes. The tests were reproduced in the numerical simulations using the solid and shell element models, and the simulation technique was validated by comparing the experimental stresses with the simulated ones. This paper considered three hotspot stress approaches: the ESM method based on surface stress extrapolation, the Dong's method based on nodal forces along a weld toe, and the proposed method based on nodal forces perpendicular to an imaginary vertical plane at a weld toe. In order to study the element sensitivities of each method, 16 solid element models and 8 shell element models were generated under the bending and tension loads, respectively. The element sensitivity was analyzed in terms of Stress Concentration Factors (SCFs) in viewpoints of two statistical quantities of mean and bias with respect to the reference SCFs. The average SCFs predicted by the proposed method were remarkably in good agreement with the reference SCFs based on the experiments and the ship rules. Negligibly small Coefficients of Variation (CVs) of the SCFs, which is measure of statistical bias, were drawn by the proposed method.

• 국제초고층학회논문집
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• 제12권1호
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• pp.93-105
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• 2023

Seismic isolation and vibration control techniques have been developed and put into practical use by challenging researchers and engineers worldwide since the latter half of the 20th century, and after more than 40 years, they are now used in thousands of buildings, private residences, highways in many seismic areas in the world. Seismic isolation and vibration control structures can keep the structures undamaged even in a major earthquake and realize continuous occupancy. This performance has come to be recognized not only by engineers but also by ordinary people, becoming indispensable for the formation of a resilient society. However, the dynamic characteristics of seismically isolated bearings, the key elements, are highly dependent on the size effect and rate-of-loading, especially under extreme loading conditions. Therefore, confirming the actual properties and performance of these bearings with full-scale specimens under prescribed dynamic loading protocols is essential. The number of testing facilities with such capacity is still limited and even though the existing labs in the US, China, Taiwan, Italy, etc. are conducting these tests, their dynamic loading test setups are subjected to friction generated by the large vertical loads and inertial force of the heavy table which affect the accuracy of measured forces. To solve this problem, the authors have proposed a direct reaction force measuring system that can eliminate the effects of friction and inertia forces, and a seismic isolation testing facility with the proposed system (E-isolation) will be completed on March 2023 in Japan. This test facility is designed to conduct not only dynamic loading tests of seismic isolation bearings and dampers but also to perform hybrid simulations of seismically isolated structures. In this paper, design details and the realization of this system into an actual dynamic testing facility are presented and the outcomes are discussed.

• Archives of Plastic Surgery
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• 제50권1호
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• pp.10-16
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• 2023

Background The chest wall defects can be caused by various reasons. In the case of malignant tumor resection of the chest wall, it is essential to reconstruct the chest wall to cover the vital tissue and restore the pulmonary function with prevention of paradoxical motion. With our experience, we analyzed and evaluated the results and complications of the chest wall reconstructions followed by malignant tumor resection. Methods From 2013 to 2022, we reviewed a medical record of patients who received chest reconstruction due to chest wall malignant tumor resection. The following data were retrieved: patients' demographic data, tumor type, type of operation, method of chest wall reconstruction of the soft and skeletal tissue and complications. Results There were seven males and six female patients. The causes of reconstruction were 12 primary tumors and one metastatic carcinoma. The pathological types were seven sarcomas, three invasive breast carcinoma, and three squamous cell carcinomas. The skeletal reconstruction was performed in six patients. The series of the flap were eight pedicled latissimus dorsi (LD) myocutaneous flaps, two pectoralis major myocutaneous flap, two vertical rectus abdominis myocutaneous free flap, and one LD free flap. Among all the cases, only one staged reconstruction and successful reconstruction without flail chest. Most of the complications were atelectasis. Conclusion In the case of accompanying multiple ribs and sternal defect, skeletal reconstruction would need skeletal reconstruction to prevent paradoxical chest wall motion. The flap for soft tissue defect be selected according to defect size and location of chest wall. With our experience, we recommend the reconstruction algorithm for chest wall defect due to malignant tumor resection.

• 한국추진공학회지
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• 제26권5호
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• pp.52-62
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• 2022

우주발사체는 가장 거대한 시스템 중의 하나로, 이처럼 장대한 발사체를 발사운용시 안전하고 신속하게 발사대로 이송하고 발사자세인 수직상태로 전환하는 것은 매우 중요한 요소이다. 이에따라, 발사체를 전기체로 총조립하고 발사대에서 발사자세인 수직자세로 만들기위한 과정은 매우 정밀한 운용방법, 절차 및 관련장치들을 필요로 한다. 이러한 이송 기립 운용 개념은 세계 각국의 우주 발사체 개발 과정 중 각각의 요구조건 및 당시의 기술수준에 맞도록 발전되어 왔다. 본 논문에서는 세계 발사체들의 이송 기립 운용 개념을 소개하고 한국의 나로호 및 누리호의 운용개념에 대해 소개한다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.508-510
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• 2021

5G버티컬들뿐만 아니라 자율운항서비스에서도 요구되는 5G요소기술들(예: 5G버티컬 위성, 5G NR(New Radio) 기반 기기 간 직접통신 기능 등)에 대한 국제표준화가 현재 진행 중임으로 자율운항선박 관련 해양통신서비스에 대한 3GPP 국제표준화를 통해 국제표준 기반 솔루션이 갖는 규모의 경제 크기 이점을 활용하면서 자율운항서비스에 활용 가능할 것으로 기대된다. 제 4차 해양산업혁명시대에 출현할 자율운항선박 관련 ICT융합시장 생태계 구축 및 국제표준 기반 핵심통신기술을 선점하기 위해 (1) 글로벌 호환성을 갖는 디지털 통신시스템 및 게이트웨이 개발, (2) 차세대통신 기반 핵심요소기술 확보, (3) 연관기술의 국제화를 위한 국제표준화 추진이 필요하다고 판단된다. 이를 위해 거리별 통신별 서비스 분석을 통한 데이터 분석 및 표준기술이 개발되어야 할 것이다. 현재 자율운항 선박 운영을 위한 요구 조건들은 주로 3가지 항목으로 분류할 수 있다.

• Composites Research
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• 제36권3호
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• pp.224-229
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• 2023

최근 각종 전자기기의 소형화와 웨어러블 디바이스의 수요가 증가함에 따라 IT 기기들의 나노화가 진행되는 추세이며, 이에 따른 배터리의 크기 및 용량 등의 한계를 극복하기 위하여 에너지 하베스팅 기술인 마찰 대전에 대한 연구가 많은 관심을 받고 있다. 불소계 코팅을 진행한 양극산화 알루미늄은 대전 서열에서 음극 성향이 높은 대전층과 대전된 전하가 전극으로 손실없이 전달되도록 도와주는 절연층 그리고 전극을 모두 포함하고 있는 구조로서 마찰 대전 나노발전기의 적용에 있어 많은 연구가 진행되어 왔다. 본 연구에서는 마찰대전 나노발전기 적용에 유리한 양극산화 알루미늄을 활용하여 마찰대전 나노발전기에 영향을 미치는 표면 형상 및 절연층의 두께를 조절하여 발전량과의 상관관계에 대하여 분석하였다. 이러한 분석을 통하여 추후 마찰대전 나노발전기 제작에 있어 면적 대비 발전량을 증가시킬 수 있는 방향을 제시할 수 있었다.

• 대한원격탐사학회지
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• 제40권1호
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• pp.1-8
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• 2024

Busan is the 6th largest port city in the world, where nitrogen dioxide (NO₂) emissions from transportation and port industries are significant. This study aims to assess the NO₂ products of the Geostationary Environment Monitoring Spectrometer (GEMS) over Busan using ground-based instruments (i.e., surface in-situ network and Pandora). The GEMS vertical column densities of NO₂ showed reasonable consistency in the spatiotemporal variations, comparable to the previous studies. The GEMS data showed a consistent seasonal trend of NO₂ with the Korea Ministry of Environment network and Pandora in 2022, which is higher in winter and lower in summer. These agreements prove the capability of the GEMS data to monitor the air quality in Busan. The correlation coefficient and the mean bias error between the GEMS and Pandora NO₂ over Busan in 2022 were 0.53 and 0.023 DU, respectively. The GEMS NO₂ data were also positively correlated with the ground-based in-situ network with a correlation coefficient of 0.42. However, due to the significant spatiotemporal variabilities of the NO₂, the GEMS footprint size can hardly resolve small-scale variabilities such as the emissions from the road and point sources. In addition, relative biases of the GEMS NO₂ retrievals to the Pandora data showed seasonal variabilities, which is attributable to the air mass factor estimation of the GEMS. Further studies with more measurement locations for longer periods of data can better contribute to assessing the GEMS NO₂ data. Reliable GEMS data can further help us understand the Asian air quality with the diurnal variabilities.

• Hip & pelvis
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• 제35권1호
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• pp.24-31
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• 2023

Purpose: A response to conservative treatment is usually obtained in cases of ischiogluteal bursitis. However, the time required to achieve relief of symptoms can vary from days to weeks, and there is a high recurrence rate, thus invasive treatment in addition to conservative treatment can occasionally be effective. Therefore, the aim of this study was to examine surgical excision in cases of refractory ischiogluteal bursitis and to evaluate patients' progression and outcome. Materials and Methods: A review of 21 patients who underwent surgical excision for treatment of ischiogluteal bursitis between February 2009 and July 2020 was conducted. Of these patients, seven patients were male, and 14 patients were female. Injection of steroid and local anesthetic into the ischial bursa was administered at outpatient clinics in all patients, who and they were refractory to conservative treatment, including aspiration and prescription drugs. Therefore, surgery was considered necessary. Excisions were performed by two orthopedic specialists using a direct vertical incision on the ischial area. A review of each patient was performed after excision, and quantification of the outcomes recorded using clinical scoring systems was performed. Results: The results of radiologic evaluation showed that the mean lesion size was 6.2 cm×4.5 cm×3.6 cm. The average disease course after excision was 21.6 days (range, 15-48 days). Measurement of clinical scores, including the visual analog scale and Harris hip scores, was performed during periodic visits, with scores of 0.7 (range, 0-2) and 98.1 (range, 96-100) at one postoperative month, respectively. Conclusion: Surgical excision, with an expectation of favorable results, could be considered for treatment of ischiogluteal bursitis that is refractory to therapeutic injections, aspirations, and medical prescriptions, particularly in moderate-to-severe cases.

• 농업과학연구
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• 제50권3호
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• pp.395-406
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• 2023

The large amount of energy required for successful crop production is the main challenge in greenhouse cropping systems. As a response to this challenge a comprehensive evaluation of greenhouse energy consumption was carried out in two structurally similar single-span greenhouses with different thermal curtain positions, with particular attention to energy productivity, specific energy, net energy, and energy ratio. The greenhouses are used for strawberry production. In the R-greenhouse (RGH), the thermal curtain hanged directly at the roof ridge, whereas in the Q-greenhouse (QGH), the thermal curtain was placed 5° from an imaginary vertical axis, from the middle of the roof ridge downwards to the north side of the greenhouse roof. The relevant data were recorded using standard methods. The results indicated that the energy expended in the RGH and QGH systems was 2,186.48 and 2,189.26 MJ/m², respectively. Electricity and nitrogen fertilizer contributed the highest energy input in both greenhouses and in all seasons. The output energy was 3.12 and 3.82 MJ/m², respectively, in RGH and QGH in season I and 4.40 and 4.87 MJ/m² in season II. In terms of energy expended, there was no significant difference between the two greenhouses, nor between the two seasons. These results indicate that greenhouses of the size used in this investigation are not viable in terms of energy productivity, energy-use efficiency, and subsequent economic performance. However, further studies should be conducted to scale-up the information obtained from this investigation.