• 유통과학연구
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• 제12권5호
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• pp.61-69
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• 2014

Purpose - Many studies report that returns on hedge portfolios that eliminate particular risk types are abnormal from traditional asset pricing models' perspectives. This study examines the pervasiveness of anomalous returns conditioned on business cycle and group size. Research design, data, and methodology - Using KOSPI and KOSDAQ market data from July 1991 to December 2013, we categorize stocks into appropriately sized groups, and dichotomize our sample periods into expansion and recession periods then, we construct hedge portfolios by sorting stocks by anomaly variables and calculate their returns. Results - Four anomalies, including earnings yield, net stock issue, total asset growth, and liquidity appear pervasive across all groups for the entire sample period. However, only the hedge returns of net stock issues are significant across all group sizes during both expansion and recession. Conclusions - A net stock issue can be an appropriate proxy for expected growth of book equity for all group sizes in recessions. This finding could provide insights to investment industry participants and to researchers interested in the relationship between expected growth of book equity and business cycle risk.

• Advances in Computational Design
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• 제7권1호
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• pp.81-98
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• 2022

This study presents the application of two indices for the locating of cracks in Reinforced Concrete (RC) structures, as well as the development of their modified forms to overcome limitations. The first index is based on mode shape curvature and the second index is based on the fourth derivative of the mode shape. In order to confirm the indices' effectiveness, both eigenvalues coupled with nonlinear static analyses were carried out and the eigenvectors for two different damage locations and intensities of load were obtained from the finite element model of RC beams. The values of the damage-locating indices derived using both indices were then compared. Generally, the mode shape curvature-based index suffered from insensitivity when attempting to detect the damage location; this also applied to the mode shape fourth derivative-based index at lower modes. However, at higher modes, the mode shape fourth derivative-based index gave an acceptable indication of the damage location. Both the indices showed inconsistencies and anomalies at the supports. This study proposed modification to both indices to overcome identified flaws. The results proved that modified forms exhibited better sensitivity for identifying the damage location. In addition, anomalies at the supports were eliminated.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.475-478
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• 2007

A solution for carbon nanotube based field emission displays has been designed and built. The solution makes use of structure layout to control electron beam trajectories, uniformity by use of ballasting, emission anomalies eliminated by selective carbon nanotube growth and invisible spacers to maintain the vacuum gap.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제5권6호
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• pp.283-288
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• 2016

최근 빅데이터 처리를 위한 연구들이 활발히 진행 중이며, 관련된 다양한 제품들이 개발되고 있다. 이에 따라, 기존 환경에서는 처리가 어려웠던 대용량 로그 데이터의 저장 및 분석이 가능해졌다. 본 논문은 다수의 서버에서 빠르게 생성되는 대량의 로그 데이터를 Apache Hive에서 분석할 수 있는 데이터 저장 구조를 제안한다. 그리고 저장된 로그 데이터로부터 특정 서버의 이상 유무를 판단하기 위해, 이동 평균 및 3-시그마 기반의 이상 탐지 기술을 설계 및 구현한다. 또한, 실험을 통해 로그 데이터의 급격한 증가폭을 나타내는 구간을 이상으로 판단하여, 제안한 이상 탐지 기술의 유효성을 보인다. 이 같은 결과를 볼 때, 본 연구는 하둡 기반으로 로그 데이터를 분석하여 이상치를 바르게 탐지할 수 있는 우수한 결과라 사료된다.

• 한국추진공학회지
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• 제26권6호
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• pp.10-20
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• 2022

본 연구에서는 케로신 다단연소사이클 엔진용 예연소기를 설계하기 위해, 고압의 산화제 과잉 조건에서 예연소가스를 계산하고 냉각유로에서 극저온 유체의 복합열전달 및 수력 특성을 해석할 수 있는 설계코드를 개발하였다. 사용자 편의성과 범용성을 가진 오픈 소스 라이브러리 Cantera를 활용하였으며, 실제유체의 열역학/전달 상태량을 정확히 계산하기 위해 관련 소스 코드들을 새로 작성하여 Cantera에 추가하였다. 현재 예비설계 중인 100톤급 부스터 엔진용 예연소기에 적용하였으며, CFD 해석결과와 비교를 통해 설계코드로서의 예측 정확도와 활용성을 확인하였다.

• 전자통신동향분석
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• 제35권1호
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• pp.60-70
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• 2020

Artificial intelligence (AI) is expected to bring about a wide range of changes in the industry, based on the assessment that it is the most innovative technology in the last three decades. The manufacturing field is an area in which various artificial intelligence technologies are being applied, and through accumulated data analysis, an optimal operation method can be presented to improve the productivity of manufacturing processes. In addition, AI technologies are being used throughout all areas of manufacturing, including product design, engineering, improvement of working environments, detection of anomalies in facilities, and quality control. This makes it possible to easily design and engineer products with a fast pace and provides an efficient working and training environment for workers. Also, abnormal situations related to quality deterioration can be identified, and autonomous operation of facilities without human intervention is made possible. In this paper, AI technologies used in smart factories, such as the trends in generative product design, smart workbench and real-sense interaction guide technology for work and training, anomaly detection technology for quality control, and intelligent manufacturing facility technology for autonomous production, are analyzed.

• 한국위성정보통신학회논문지
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• 제6권2호
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• pp.112-116
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• 2011

우주 인프라 영향분석 툴은 태양폭발이 지구 궤도 상의 위성에 미치는 영향 분석과 통계 모델 도출 연구에 필요한 데이터의 체게적인 제공과 위성에 장애를 주는 핵심 요인에 대한 통계적 분석을 수행하는데 필요한 정보를 제공한다. 또한 위성장애와 관련된 우주전파환경 국내외 연구 자료를 종합적으로 검색할 수 있는 기능을 함께 제공함으로써 외국의 연구결과와 비교할 수 있는 환경을 제공한다. 본 논문은 DB 설계를 포함한 우주 인프라 영향분석 툴 설계 연구 결과를 제시한다.

• Smart Structures and Systems
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• 제29권4호
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• pp.561-576
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• 2022

Heritage timber structures represent the history and culture of a nation. These structures have been inherited from previous generations; however, they inevitably exhibit deterioration over time, potentially leading to structural deficiencies. Structural Health Monitoring (SHM) offers the potential to assess operational anomalies, deterioration, and damage through processing and analysis of data collected from transducers and sensors mounted on the structure. This paper reports on the design and implementation of a long-term SHM system on the Feiyun Wooden Pavilion in China, a three-story timber building built more than 500 years ago. The principles and features of the design and implementation of SHM systems for heritage timber buildings are systematically discussed. In total, 104 sensors of 6 different types are deployed on the structure to monitor the environmental effects and structural responses, including air temperature and humidity, wind speed and direction, structural temperatures, strain, inclination, and acceleration. In addition, integrated data acquisition and transmission subsystem using a newly developed software platform are implemented. Selected preliminary statistical and correlation analysis using one year of monitoring data are presented to demonstrate the condition assessment capability of the system based on the monitoring data.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2008년도 공동학술대회
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• pp.27-32
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• 2008

Mariana 해령 후열도 분지내에 위치하고 있는 Esmeralda Bank의 지형 및 자력 특성을 연구하고 열수분출대의 위치를 추정하기 위하여 2007년 9월에 한국해양연구원 온누리호를 이용하여 획득한 정밀해저지형자료 및 해상자력탐사자료를 함께 분석하였다. Esmeralda Bank의 전체적인 모양은 서쪽 방향이 열린 칼데라의 형태를 띠고 있다. Esmeralda Bank의 정상부의 수심은 약 50 m로 매우 얕고 기저부의 수심은 약 1300m이다. Esmeralda Bank의 서쪽부분은 동쪽부분보다 경사가 더 급하고 지형의 기복이 심하게 나타나며, Bank 생성 후 무너져 내렸거나 침식에 의해 형성된 것으로 보이는 계곡이 관찰된다. Esmeralda Bank의 자기이상분포는 두 지역 모두 북쪽에 저이상이 나타나고 남쪽에 고이상이 분포하며 정상부에서는 급격한 자기변화를 보이고 수심이 깊은 기저부에서는 완만한 자기변화가 나타난다. Esmeralda Bank는 정상부와 서쪽에 저자화이상대가 분포하고 있다. Esmeralda Bank 정상부의 저자화 이상대에서 열수분출대가 존재할 가능성이 있다.

• Archives of Plastic Surgery
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• 제46권1호
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• pp.16-22
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• 2019

Background Various surgical techniques have been used to correct Tessier number 7 craniofacial cleft, which involves macrostomia, ear deformity, and hemifacial microsomia. To achieve symmetrical and satisfactory results in patients with macrostomia, the authors performed a 1-mm medial overcorrection on the cleft side and evaluated the results of this procedure. Methods A retrospective medical record review of patients diagnosed with Tessier number 7 craniofacial cleft from March 1999 to February 2017 was performed. Using clinical photographs, outpatient clinic records, and operative records, information was recorded regarding concurrent congenital anomalies, postoperative complications, and follow-up. Using Photoshop CS2, the length of both sides of the lip was compared. The ratio of these lengths was calculated to evaluate lip symmetry. Results Of the patients treated at the Department of Plastic and Reconstructive Surgery at Kyungpook National University Chilgok Hospital, 11 (male-to-female sex ratio, 7:4) were diagnosed with Tessier number 7 craniofacial cleft. Concurrent congenital anomalies included skin tag, hemifacial microsomia, and cleft palate. The mean duration of follow-up was $78.273{\pm}72.219$ months and the mean ratio of the lengths of both sides of the lip was $1.048{\pm}0.071$. Scar widening occurred as a postoperative complication in some patients. No cases of wound infection, bleeding, or wound dehiscence occurred. Conclusions For the successful correction of macrostomia, plastic surgeons should consider both functional and aesthetic problems of the lip. Adequate repair of the orbicularis oris muscle, skin closure with Z-plasty, and medial overcorrection of the neo-oral commissure led to good results in our patients.