• Smart Structures and Systems
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• 제21권5호
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• pp.687-694
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• 2018

The problem of wheel tread defects has become a major challenge for the health management of high-speed rail as a wheel defect with small radius deviation may suffice to give rise to severe damage on both the train bogie components and the track structure when a train runs at high speeds. It is thus highly desirable to detect the defects soon after their occurrences and then conduct wheel turning for the defective wheelsets. Online wheel condition monitoring using wheel impact load detector (WILD) can be an effective solution, since it can assess the wheel condition and detect potential defects during train passage. This study aims to develop an FBG-based track-side wheel condition monitoring method for the detection of wheel tread defects. The track-side sensing system uses two FBG strain gauge arrays mounted on the rail foot, measuring the dynamic strains of the paired rails excited by passing wheelsets. Each FBG array has a length of about 3 m, slightly longer than the wheel circumference to ensure a full coverage for the detection of any potential defect on the tread. A defect detection algorithm is developed for using the online-monitored rail responses to identify the potential wheel tread defects. This algorithm consists of three steps: 1) strain data pre-processing by using a data smoothing technique to remove the trends; 2) diagnosis of novel responses by outlier analysis for the normalized data; and 3) local defect identification by a refined analysis on the novel responses extracted in Step 2. To verify the proposed method, a field test was conducted using a test train incorporating defective wheels. The train ran at different speeds on an instrumented track with the purpose of wheel condition monitoring. By using the proposed method to process the monitoring data, all the defects were identified and the results agreed well with those from the static inspection of the wheelsets in the depot. A comparison is also drawn for the detection accuracy under different running speeds of the test train, and the results show that the proposed method can achieve a satisfactory accuracy in wheel defect detection when the train runs at a speed higher than 30 kph. Some minor defects with a depth of 0.05 mm~0.06 mm are also successfully detected.

• Nuclear Engineering and Technology
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• 제47권4호
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• pp.454-460
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• 2015

Acoustic emission (AE) is one of the promising methods for detecting the formation of stress corrosion cracks (SCCs) in laboratory tests. This method has the advantage of online inspection. Some studies have been conducted to investigate the characteristics of AE parameters during SCC propagation. However, it is difficult to classify the distinct features of SCC behavior. Because the previous studies were performed on slow strain rate test or compact tension specimens, it is difficult to make certain correlations between AE signals and actual SCC behavior in real tube-type specimens. In this study, the specimen was a AISI 304 stainless steel tube widely applied in the nuclear industry, and an accelerated test was conducted at high temperature and pressure with a corrosive environmental condition. The study result indicated that intense AE signals were mainly detected in the elastic deformation region, and a good correlation was observed between AE activity and crack growth. By contrast, the behavior of accumulated counts was divided into four regions. According to the waveform analysis, a specific waveform pattern was observed during SCC development. It is suggested that AE can be used to detect and monitor SCC initiation and propagation in actual tubes.

• 중소기업융합학회논문지
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• 제5권3호
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• pp.9-13
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• 2015

ICT 발달로 인해 면대면이 아닌 온라인 상에서 상대방의 신원을 확인하는 사용자인증 필요성이 증가하고 있다. 사용자인증은 보안의 기본으로 여러 분야에서 사용되고 있다. ID기반의 인증은 안전성과 분실 가능성이 많아 보안이 요구되어지는 곳에서는 2개 이상의 인증도구를 사용하게 된다. 최근에 ID나 OTP, SMS 인증보다 생체인증이 신뢰성 등에서 효과적인 측면으로 많이 고려되고 있다. 최근 생체인식 기술을 응용하여 적용되는 분야들이 다양하게 증가함에 따라 생체인식에 대한 적용도 모바일 결제 시스템, 지능형 CCTV, 출입국심사, 출입통제 등 다양한 분야에서 사용되고 있다. 생체인식으로는 지문, 홍체, 망막, 정맥 등에 이어 얼굴인식에 대한 연구가 활발히 이루어지고 있다. 본 논문에서는 얼굴인식 기술의 이해와 기술 동향를 비롯한 국내외 표준화 현황에 대해 알아보고 한다.

• Journal of Biosystems Engineering
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• 제39권2호
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• pp.142-149
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• 2014

Purpose: A multispectral algorithm for detection and differentiation of defective (defects on apple skin) and normal Red Delicious apples was developed from analysis of a series of hyperspectral line-scan images. Methods: A fast line-scan hyperspectral imaging system mounted on a conventional apple sorting machine was used to capture hyperspectral images of apples moving approximately 4 apples per second on a conveyor belt. The detection algorithm included an apple segmentation method and a threshold function, and was developed using three wavebands at 676 nm, 714 nm and 779 nm. The algorithm was executed on line-by-line image analysis, simulating online real-time line-scan imaging inspection during fruit processing. Results: The rapid multispectral algorithm detected over 95% of defective apples and 91% of normal apples investigated. Conclusions: The multispectral defect detection algorithm can potentially be used in commercial apple processing lines.

• 대한한방소아과학회지
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• 제35권3호
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• pp.100-117
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• 2021

Objectives The purpose of this study is to investigate the satisfaction and improvement points of the current health checkup in infants and children, and recognition of parents about introduction of health examinations for infants and children by Korean medicine. Methods We conducted an online survey through the website of Dongguk University Bundang Korean medicine hospital for the parent of infants and children between 4 and 71 months age who received at least one health checkup. Statistical processing was performed using the SPSS Version 23.0 program. Results As a result of correlation analysis between the degree of necessary improvement point of current health checkup for infants and children and the degree of strength of health examinations for infants and children by Korean medicine, there was a statistically significant positive correlation (r=0.957). With the participation of Korean medical doctors, it can be expected that the number of health examinations centers for infants and children will be expanded, screening services will be increased, and oriental medicine childcare and education to prevention of major pediatrics disease can be provided. Conclusions These results show that health examinations for infants and children by Korean medicine can increase the satisfaction of the parent and the inspection rate.

• 한국의류산업학회지
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• 제23권1호
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• pp.129-141
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• 2021

This study investigated fabrics, washing and cares, design, pattern, subsidiary materials, and sewing methods with a focus on the functional outers using moisture-permeable waterproof fabric as a shell; in addition, each element was analyzed for differences depending on fabric type. The characteristics of 34 outers were investigated through labels, online product introductions, visual inspection, observations from two experts with more than 30 years experience and wear tests. Moisture-permeable waterproof fabrics used for the outer were classified into two types; in addition, the shell of the high-density fabric and the 2 & 3-layer fabrics had different characteristics. Various fabrics, detailed designs, and three-dimensional patterns suitable for each part of the human body were used to improve functionality. In addition, various subsidiary materials and sewing methods were used to form an organic relationship. The same washing and cares, patterns and subsidiary materials were used regardless of fabric type; however, the fabric type influenced the detailed design and sewing. The outers with high-density fabric had a loose fit, short placket, e-banded cuffs, lock-stitch, and lock-stitch+binding. However, the outer with 2 & 3 layer fabric had a slim fit, hood width adjustment, zippered pockets, cuffs with tab, seamless adhesive sewing such as laminating, lock-stitch+ seam-sealing, and welding.

• 창의정보문화연구
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• 제7권3호
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• pp.117-128
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• 2021

이 연구는 중고등학생들의 비대면 수업적응력을 알아보고자 하는 검사 도구를 개발하는 데 목적을 두고 있다. 연구대상은 충북지역 중고등학교 4개교 학생들을 대상으로 2개월에 걸쳐 이루어졌다. 추출 결과, 도구 활용, 책임감, 집중력, 자신감, 적응력, 협력성의 6개 요인 24문항의 비대면 수업적응력 검사지가 만들어졌다. 검사의 양호도 분석 결과는 다음과 같다. 첫째, 문항 내적 일관성의 신뢰도 계수는 전체 Chronbach's α는 .888로 나타났으며, 영역별 신뢰도 범위는 .621~.854로 나타나 충분히 신뢰할 수 있다. 둘째, 확인적 요인분석에 의한 구인타당도 검증 결과는 CFA 모델에서 절대적합도 지수인 RMSEA=.0108, SRMR=.0794로 양호한 범주에 들고 있어 각 영역에 속하는 문항들이 중고등학생들의 비대면 수업적응력을 알아보고자 하는 특성을 적절하게 포함하고 있는 것을 확인해 주었다.

• 대한암한의학회지
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• 제27권1호
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• pp.13-23
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• 2022

Objective: The purpose of this review is to analyze the clinical studies on tongue diagnosis in cancer patients. Methods: Domestic and foreign databases were used, such as Pubmed, google scholar, Wanfang med online, Scopus, and OASIS. Searching keywords were tongue diagnosis, tongue color, tongue fur, tongue inspection, cancer, tumor, neoplasm, carcinoma, etc. Studies on tongue diagnosis in cancer patients were included. The published year was limited from 2000 to June 2022. Results: Thirteen studies were enrolled. All selected studies were cross-sectional studies. Cancer patients tend to have a dark and blue-purple tongue, thick fur, yellow fur, fissure tongue, and red dots on the tongue compared with non-cancer patients. With the aggravation of cancer, the rate of patients having dark or blue, or purple tongues increased, and the patients' sublingual veins became wide and tortuous. Conclusion: This study suggests that cancer patients tend to have distinct features of tongue diagnosis. Further researches are warranted.

• 한국안전학회지
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• 제39권1호
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• pp.55-61
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• 2024

In response to the COVID-19 pandemic, the logistics industry in Korea has rapidly been expanding, with offline demand concentrating on online platforms owing to the development of digital infrastructure. This has increased the workload of courier drivers considerably, along with labor intensity. A delivery driver died recently from overwork due to the continuous increase in delivery volume, which raises social concerns. Delivery drivers work long hours, (over 12 hours) and are greatly affected by weather conditions, such as snow, rain, heat waves, and cold waves. In addition, they lack a fixed workplace; perform atypical work handling workpieces of various sizes, weights, and shapes; and spend a large amount of time driving as part of their work. This work involves a high level of tension and requires attention and concentration. Despite the frequency of industrial accidents in the courier industry, studies on safety and health to quantitatively analyze and systematize the work of courier workers are very scarce. Therefore, to define the work process necessary for investigating the harmful factors in delivery service and the work analysis, this study conducted interviews and on-site surveys to analyze the unit work of the delivery service by targeting delivery workers. In other words, a framework of unit work for work analysis was presented to enable research and analysis by considering the aforementioned characteristics of the courier industry. The process was broadly divided into work, transport, storage, delay, and inspection. Work was divided into loading, sorting, unloading, and door subcategories, and transportation was divided into vehicle, cart, and walking subcategories as well as 10 small processes. Moreover, 22 unit works were again drawn by conducting field surveys and interviews. The risk of unit work derived from this study was ergonomically evaluated, and the ergonomic analysis revealed that uploading and transportation were the most dangerous. The results of this study could be used as basic data for preventing industrial accidents among courier workers, whose work has increased with the logistics volume and the development of the logistics industry.

• 인지과학
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• 제21권2호
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• pp.309-338
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• 2010

본 논문에서는 사지가 마비되어 신체를 움직이지 못하지만 뇌의 기능은 살아있는 장애인들을 위하여, 생각만으로 외부의 장치를 제어할 수 있도록 하는 뇌-컴퓨터 인터페이스(BCI: Brain-Computer Interface) 기술을 연구하였다. 신경생리학 분야에서의 연구 결과에 의하면, 신체를 움직이는 상상을 할 경우, 뇌의 운동/감각 피질 영역에서는 $\beta$파(14-26 Hz)와 $\mu$파(8-12 Hz)가 억제/증가되는 ERD/ERS(Event-Related Desynchronization / Synchronization) 현상이 발생한다고 알려져 있다. 본 연구에서는 이를 기반으로 혀, 발, 왼손, 오른손의 동작 상상을 자극으로 이용하여 변화하는 뇌 신호 패턴을 실시간으로 분석하여 피험자의 생각을 읽을 수 있도록 하였으며, 상 하 좌 우의 네 방향으로 이동할 수 있도록 하는 마우스 제어 인터페이스를 구현하였다. 동작 상상 시 발생하는 뇌 신경 활동의 변화를 관측하기 위해서 뇌에 손상을 주지 않으면서도 높은 시간 해상도로 측정이 가능한 비침습적 뇌전도(EEG: ElectroEncephaloGraphy)를 이용하였다. 그러나 뇌전도 신호는 특성상 신호의 크기가 미약하고, 잡음의 영향을 많아 분석이 어렵다. 따라서 이를 극복하기 위해 통계적 방법을 기반으로 한 기계학습 기법인 CSP(Common Spatial Pattern)와 선형판별 분석(Linear Discriminant Analysis)을 이용하여 서로 다른 동작 상상에 의해 발생하는 뇌 신호들 간의 분산이 최대가 되도록 신호를 변환하여 인식 성능을 높일 수 있었다. 또한 분석된 뇌 신호의 시각화를 통해, 기존에 알려진 뇌의 해부학적, 신경생리학적 지식과 일치하는 ERD/ERS 현상이 발생하는 것을 확인할 수 있었다.