• 한국지능시스템학회논문지
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• 제24권3호
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• pp.316-322
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• 2014

본 논문은 TV를 이용한 영화시청 환경에서 해당 컨텐트에 대한 시청자의 암묵적 반응과 컨텐트의 멀티모달 피쳐를 실시간으로 측정 및 동기화하여 이를 기반으로 동영상 선호모델을 지속적으로 개선하고 필요시 영화추천을 수행하는 시스템을 제안한다. 제안한 시스템에선 이미지, 소리, 자막 스트림으로부터 실시간 추출되는 저수준 피쳐들과 동기화되어 측정된 얼굴표정, 자세 및 생체신호로부터 해당 동영상이 유발한 시청자의 감정상태를 추정하여 선호모델 학습에 사용한다. 제안한 컨텐트-시청자 연계 추천모델의 일례로서 컨텐트의 오디오 및 자막 정보를 이용하여 시청자의 피부전기활성도로 측정된 arousal반응을 예측할 수 있음을 보인다.

• 한국인터넷방송통신학회논문지
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• 제21권6호
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• pp.155-161
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• 2021

최근, 실시간으로 카메라를 통해 동작을 인식하는 기술의 연구가 많이 진행되고 있다. 기존의 연구들에서는 사람의 관절로부터 특징을 추출하는 개수가 적기 때문에 동작 분류의 정확도가 낮은 한계점들이 있다. 본 논문에서는 이러한 한계점들을 해결하기 위해 움직일 때 변하는 관절의 각도를 특징 추출하여 계산하는 알고리즘과 이미지 분류 시에 정확도가 높은 CBAM(Convolutional Block Attention Module)을 사용한 분류모델을 제안한다. AI Hub에서 제공하는 피트니스 자세 이미지로부터 5가지 운동 동작 이미지를 인용하여 분류 모델에 적용한다. 구글에서 제공하는 그래프 기반 프레임워크인 MediaPipe 기법을 사용하여, 이미지로부터 운동 동작 분류에 중요한 8가지 관절 각도 정보를 추가적으로 추출한다. 추출한 특징들을 모델의 입력으로 설정하여, 분류 모델을 학습시킨다. 시뮬레이션 결과로부터 제안한 모델은 높은 정확도로 운동 동작을 구분하는 것을 확인할 수 있다.

• 제어로봇시스템학회논문지
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• 제21권12호
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• pp.1100-1108
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• 2015

A camera-based real-time hand posture and gesture recognition system is proposed for controlling various devices inside automobiles. It uses an imaging system composed of a camera with a proper filter and an infrared lighting device to acquire images of hand-motion sequences. Several steps of pre-processing algorithms are applied, followed by a background normalization process before segmenting the hand from the background. The hand posture is determined by first separating the fingers from the main body of the hand and then by finding the relative position of the fingers from the center of the hand. The beginning and ending of the hand motion from the sequence of the acquired images are detected using pre-defined motion rules to start the hand gesture recognition. A set of carefully designed features is computed and extracted from the raw sequence and is fed into a decision tree-like decision rule for determining the hand gesture. Many experiments are performed to verify the system. In this paper, we show the performance results from tests on the 550 sequences of hand motion images collected from five different individuals to cover the variations among many users of the system in a real-time environment. Among them, 539 sequences are correctly recognized, showing a recognition rate of 98%.

• 대한의용생체공학회:의공학회지
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• 제41권4호
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• pp.165-171
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• 2020

In this study, it focuses on the development of radiographic devices for patellar imaging. On the previous X-ray examination of patella and patellofemoral joint, it analyzed the problems which could affect the results: unstable patients' pose, radiation exposure, and deterioration of image quality. The purpose of the research is to propose a future use of a developed device with an explanation of the process, function, and advantage of the device including the methods. The device is developed to focus on the diagnosis of the longitudinal and longitudinal fractures of the patella and patella/femoral joint, displacement such as dislocation, bone formation, stenosis of the patella/femorla joint, and cartilage wear. Due to the patient's anxious posture, it caused a shaking image, overlapping structures, and etcs, these factors challenge to diagnose accurately. In addition, the existing Settegast method and Hughston method, which are most frequently performed in the hospital field, are not suitable for the presence or absence of features or dislocation due to the heavy load on the patella of the patient. The developed device requires patients in a lying position and placing only their leg on the device, it increases the conveniences of the examination and decreases unnecessary radiation exposure of the patient except the patellar examination area. Moreover, one of the systems in the device fixes the detector, where the patients no longer need to hold the detector nor be in unstable posture, but describes the structure of the patella/femoral joint more clearly. Hoping the device will apply to more patients.

• Journal of Korean Neurosurgical Society
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• 제55권3호
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• pp.148-151
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• 2014

Objective : Posture-induced radial neuropathy, known as Saturday night palsy, occurs because of compression of the radial nerve. The clinical symptoms of radial neuropathy are similar to stroke or a herniated cervical disk, which makes it difficult to diagnose and sometimes leads to inappropriate evaluations. The purpose of our study was to establish the clinical characteristics and diagnostic assessment of compressive radial neuropathy. Methods : Retrospectively, we reviewed neurophysiologic studies on 25 patients diagnosed with radial nerve palsy, who experienced wrist drop after maintaining a certain posture for an extended period. The neurologic presentations, clinical prognosis, and electrophysiology of the patients were obtained from medical records. Results : Subjects were 19 males and 6 females. The median age at diagnosis was 46 years. The right arm was affected in 13 patients and the left arm in 12 patients. The condition was induced by sleeping with the arms hanging over the armrest of a chair because of drunkenness, sleeping while bending the arm under the pillow, during drinking, and unknown. The most common clinical presentation was a wrist drop and paresthesia on the dorsum of the 1st to 3rd fingers. Improvement began after a mean of 2.4 weeks. Electrophysiologic evaluation was performed after 2 weeks that revealed delayed nerve conduction velocity in all patients. Conclusion : Wrist drop is an entrapment syndrome that has a good prognosis within several weeks. Awareness of its clinical characteristics and diagnostic assessment methods may help clinicians make diagnosis of radial neuropathy and exclude irrelevant evaluations.

• 대한인간공학회지
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• 제34권2호
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• pp.151-165
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• 2015

Objective: This study aims to develop and scientifically investigate the efficacy of the Spine S-curve Reactive Backrest that responds to the spine curvature of the user when seated, and maintains and enhances the natural S-curve of the lower back, thereby helping to relieve fatigue, correct posture and prevent spine deformities. Background: The focus of current development, design guidelines and/or standards for office chairs is mainly placed on the chair's dimensions, incline angle, adjusting features and lumbar support. Research and development was called for developing a chair backrest that maintains and improves the S-curve of the full spine. Method: The Spine S-curve Reactive Backrest was ergonomically designed to maintain correct posture and enhance user comfort. When leaned on, the backrest responds to the user's spine line and the whole lower back sits closely against the backrest, thereby aligning the user's lower back and backrest as one to maintain and improve the natural S-curve formation of the spine. In order to evaluate the efficacy of the newly designed chair (new design) and the comparison target (chair), five male college students of standard body type with normal spine curvature were selected as test subjects, and a motion analyzer and electromyography were utilized to measure S-curve and erector spinae muscle activity when seated. Results: The spine S-curve was better maintained and improved when sitting in the new design than in the comparison chair. Particularly notable was the greater displacement gap of the thoracic spine than the cervical spine, and also that of the lumbar more than the thoracic spine, with the increase of the backrest tilting angle. Furthermore, the electromyogram results showed the new design caused a lower fatigue level of the erector spinae muscles compared to the comparison chair, and also earned a higher preference in the subjective opinion results. Conclusion: The newly designed chair in this study responds to the user's spine curvature and maintains and enhances the lower back's natural S-curve, and thereby relieves fatigue, promotes better posture, and helps to prevent spine deformities better than existing office chairs. There is a need to widely introduce and supply this new design. Application: The new design is applicable to office and student chairs, and is expected to improve concentration and work efficiency.

• 대한인간공학회지
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• 제36권2호
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• pp.69-86
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• 2017

Objective: The present study is intended to develop an improved bus seat armrest design by evaluating various bus armrest designs from ergonomic aspects. Background: An ergonomic armrest design which considers the sitting postures and body shapes of passengers can improve the convenience and comfort of a bus seat. Method: Subjective satisfaction of each of five design dimensions (length, width, height from seatpan, shape, and angle) was evaluated for seven bus seat armrest designs in various sizes and shapes by 58 participants (28 males and 33 females) using a 7-point scale (1: very dissatisfied, 4: neutral, and 7: very satisfied). Improved bus seat armrest designs adjustable in length and rotatable to the left or right (sliding and rotating armrest, SRA) with a concave, flat, or convex shape of the upper part were developed by considering the preferred design features and the body size and shape in sitting posture and needs of passengers and then compared with a conventional armrest. Results: A bus seat armrest with a wide width (40~50mm), a long length (360mm), a lower height (213mm), and a curved shape was found significantly preferred in terms of comfort. The proposed armrest designs (SRA-convex, SRA-flat, and SRA-concave) improved satisfaction by 46~62% for length suitability, 184~216% for width suitability, 205~214% for angle suitability, 138~181% for contact area suitability, and 49~64% for height suitability, 138~174% for comfort, and 93~111% for overall satisfaction. Conclusion: The preferred design features and passengers' needs of bus seat armrest were identified and the SRA designs were recommended for better usability. Application: The ergonomic design process of bus seat armrest employed in the present study can be applied to designing armrests in various vehicles for better convenience and comfort.

• 한국정보과학회논문지:소프트웨어및응용
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• 제30권9호
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• pp.885-893
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• 2003

본 논문은 3차원 얼굴영상으로부터 얼굴의 구성 요소 중의 하나인 코의 종단면과 횡단면을 이용한 특징값과 얼굴의 다를 구성 요소들로부터 구해진 특징값을 이용하여 얼굴을 인식하는 알고리듬을 제안한다. 객체와 배경을 분리하여 얼굴을 추출 및 얼굴의 최고점인 코끝을 찾은 후, 3차원 영상으로부터 얼굴의 주요 특징영역인 코 정보와 얼굴의 종단면 및 횡단면의 정보를 이용하여 회전 보상 전, 후의 특징값을 구한다. 코의 최고점, 코와 이마 사이의 미간점, 코의 밑점, 그리고 코의 앙쪽 끝점을 탐색하여 코의 종단면과 횡단면을 기준으로 한 면적, 깊이, 각도, 체적, 그리고 눈과 입의 간격을 특징값으로 사용하였다. 제안된 방법을 이용한 유사도 비교는 입력과 데이타 베이스에 대하여 각각 두 개의 깊이 데이타에 대해 유클리드 거리를 사용하였으며, 실험결과 임계 순위 값 5위 이내의 인식률이 95.5%로 나타났다.

• Clinical and Experimental Pediatrics
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• 제59권1호
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• pp.30-34
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• 2016

Purpose: Although Bednar's aphthae are common and regress spontaneously, these lesions may lead to feeding intolerance and are often misdiagnosed, rendering examinations useless. This study sheds new light on the clinical features of Bednar's aphthae. Methods: Sixteen neonates and infants were newly diagnosed with Bednar's aphthae via routine health check-ups in an outpatient clinic. Medical records were retrospectively reviewed, and the following parameters were analyzed; sex, gestational age, birth weight, mode of delivery, and perinatal problems. A physical examination was carried out during the next outpatient visit to examine the healing process and check for the existence of scars or complications. Results: Initial presentation included changes in feeding habits (n=10), longer feeding time, reduced intake, and increased irritability. In 6 patients, Bednar's aphthae were discovered incidentally, without prior symptoms. Feeding posture and method of feeding are important causes of Bednar's aphthae. Eleven patients were fed in a horizontal position, whereas 5 patients were fed in a semiseated position. Fifteen patients were bottle-fed, whereas 1 patient was exclusively breastfed. After correcting the feeding position, the ulcerative lesions disappeared within 1 month of diagnosis. During the follow-up period, lesions did not recur in any of the patients. Conclusion: This study suggests that Bednar's aphthae are caused by mechanical pressure. A diagnosis of Bednar's aphthae should be considered when lesions are found on the palate of infants and when symptoms seem to be feeding related. Proper education of parents can both treat Bednar's aphthae and easily prevent its recurrence.

• 대한인간공학회지
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• 제29권2호
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• pp.203-210
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• 2010

For the development of a better product which fits to the target user population, physical workloads such as reach and visibility are evaluated using digital human simulation in the early stage of product development; however, ergonomic workload assessment mainly relies on visual observation of reach envelopes and view cones generated in a 3D graphic environment. The present study developed a quantitative assessment method of physical workload in a digital environment and applied to the evaluation of a Korean utility helicopter (KUH) cockpit design. The proposed assessment method quantified physical workloads for the target user population by applying a 3-step process and identified design features requiring improvement based on the quantified workload evaluation. The scores of physical workloads were quantified in terms of posture, reach, visibility, and clearance, and 5-point scales were defined for the evaluation measures by referring to existing studies. The postures of digital humanoids for a given task were estimated to have the minimal score of postural workload by finding all feasible postures that satisfy task constraints such as a contact between the tip of the index finger and a target point. The proposed assessment method was applied to evaluate the KUH cockpit design in the preliminary design stage and identified design features requiring improvement. The proposed assessment method can be utilized to ergonomic evaluation of product designs using digital human simulation.