• 제목/요약/키워드: Measurement criteria

검색결과 983건 처리시간 0.026초

운용중 모드해석 방법과 신경망을 이용한 온라인 유한요소모델 업데이트 (On-line Finite Element Model Updating Using Operational Modal Analysis and Neural Networks)

  • 박원석
    • 한국전산구조공학회논문집
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    • 제34권1호
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    • pp.35-42
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    • 2021
  • 이 논문에서는 공용중인 구조물의 상시 계측 자료를 사용한 온라인 유한요소 모델 업데이트 방법을 제안한다. 일반적인 최적화 방법에 기반한 기존의 방법은 최적해를 찾기까지 반복적으로 고유치 해석을 수행해야 하므로 상시 업데이트에 사용하기에는 효과적이지 못하다. 제안하는 방법은 별도의 오프라인 작업이나 사용자의 개입이 없이 자동화된 과정으로 계측과 동시에 온라인 유한요소모델 업데이트를 수행할 수 있는 새로운 방법이다. 자동화된 Cov-SSI 알고리즘을 통해 구조물의 진동 계측 신호로부터 고유진동수 및 모드 형상을 식별하고, 이를 다시 역 고유치 신경망에 입력하여 최종적으로 업데이트된 유한요소 모델의 파라미터를 추정한다. 풍하중을 받는 20층 전단 빌딩 구조 모형에 대한 수치예제를 통해 제시한 방법이 자동으로 연속적인 유한요소모델 업데이트를 할 수 있었음을 확인하였다. 또한, 계측 도중 구조물의 특성이 변화하는 시나리오에 대한 예제에서 구조물의 변화가 일어나는 시점과 변화 후 변동된 구조 모델 파라미터 값을 성공적으로 추정할 수 있음을 확인하였다.

건강한 성인의 전거근의 선택적인 활성화를 향상시키는 효과적인 큐잉 방법 (Effective Cueing Method That Increases Selective Muscle Activation of the Serratus Anterior in Healthy Adults)

  • 최종재;송창호
    • PNF and Movement
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    • 제19권2호
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    • pp.269-278
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    • 2021
  • Purpose: This study aimed to investigate effective cueing methods for selective muscle activation of the serratus anterior. Methods: Based on the inclusion criteria, 26 healthy adults, both males and females, were recruited for the measurement of muscle activation of the upper trapezius and serratus anterior muscles while performing basic movements in knee push-up plus (KPP) and dynamic hug (DH) positions using five different cueing methods. An electromyogram was used to measure muscle activation, and both muscle activation and muscle ratio (serratus anterior/upper trapezius) were compared during the basic movements and different cueing methods. The cueing methods were trapezius verbal cueing, trapezius verbal cueing + trapezius tactile cueing, emphasis verbal cueing, serratus anterior tactile cueing, and trapezius verbal cueing + trapezius tactile cueing + serratus anterior tactile cueing. Results: The results of the study showed that there was a significant difference in the muscles for the two exercises (p < 0.05). There was also a significant difference between the cueing methods (p < 0.05). The correlative effect between the muscles and cueing methods was also significant (p < 0.05). The muscle ratio in trapezius verbal cueing + trapezius tactile cueing + serratus anterior tactile cueing during KPP and DH was higher than in basic movements and other cueing methods. This confirms that trapezius verbal cueing + trapezius tactile cueing + serratus anterior tactile cueing is an effective cueing method for selective activation of the serratus anterior during KPP and DH. This study also demonstrated that cueing by a therapist may both increase and decrease selective muscle activation. Conclusion: Through this study, an effective cueing method to selectively activate the serratus anterior may be suggested, and the results of this study may provide basic information regarding future studies and clinical practice.

비쇄파조건에서 경사식구조물의 개별 최대월파량 산정 (Estimation for Maximum Individual Wave Overtopping of a Rubble Mound Structure under Non-breaking Conditions)

  • 이종인;정정국
    • 대한토목학회논문집
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    • 제41권6호
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    • pp.663-673
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    • 2021
  • 해안구조물 설계시 허용평균월파량은 설계요소중의 하나이며, 구조물의 마루높이는 구조물의 안전, 보행자의 안전 및 운영 등에 요구되는 월파량 이하가 되도록 하여야 한다. 최근 들어 보다 안전한 설계를 위해 평균월파량보다 개별 최대월파량을 기준으로 적용하자는 제안이 이루어지고 있다. 본 연구는 비쇄파조건에서 개별 최대월파량에 대한 정보를 제공하고자 하는 것이며, 경사식구조물의 기하학적 형상을 고려안 2차원 수리모형실험을 수행하였다. 또한 실험을 위해 새로운 계측방법을 고안하였다. 실험결과를 이용하여 평균월파량에 기반하여 개별 최대월파량을 산정할 수 있는 경험식을 제안하였다. 그리고 피복재 어깨폭에 따른 평균월파량의 저감효과에 대해서도 검토하였다.

생체 신호 기반 음주량 예측 및 음주량에 따른 운전 능력 평가 (Prediction of Alcohol Consumption Based on Biosignals and Assessment of Driving Ability According to Alcohol Consumption)

  • 박승원;최준원;김태현;서정훈;정면규;이강인;김한성
    • 대한의용생체공학회:의공학회지
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    • 제43권1호
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    • pp.27-34
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    • 2022
  • Drunk driving defines a driver as unable to drive a vehicle safely due to drinking. To crack down on drunk driving, alcohol concentration evaluates through breathing and crack down on drinking using S-shaped courses. A method for assessing drunk driving without using BAC or BrAC is measurement via biosignal. Depending on the individual specificity of drinking, alcohol evaluation studies through various biosignals need to be conducted. In this study, we measure biosignals that are related to alcohol concentration, predict BrAC through SVM, and verify the effectiveness of the S-shaped course. Participants were 8 men who have a driving license. Subjects conducted a d2 test and a scenario evaluation of driving an S-shaped course when they attained BrAC's certain criteria. We utilized SVR to predict BrAC via biosignals. Statistical analysis used a one-way Anova test. Depending on the amount of drinking, there was a tendency to increase pupil size, HR, normLF, skin conductivity, body temperature, SE, and speed, while normHF tended to decrease. There was no apparent change in the respiratory rate and TN-E. The result of the D2 test tended to increase from 0.03% and decrease from 0.08%. Measured biosignals have enabled BrAC predictions using SVR models to obtain high Figs in primary and secondary cross-validations. In this study, we were able to predict BrAC through changes in biosignals and SVMs depending on alcohol concentration and verified the effectiveness of the S-shaped course drinking control method.

교통사고 상해증후군의 한의치료에 대한 경제성평가를 위한 주제범위 문헌고찰 (A Scoping Review for Economic Evaluation of Korean Medicine for Whiplash Associated Disorders)

  • 강신우;황윤경;황만석;이혜윤
    • 척추신경추나의학회지
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    • 제16권2호
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    • pp.97-105
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    • 2021
  • Objectives This study is aimed to evaluate cost-effectiveness of treatment of Korean Medicine for whiplash associated disorders (WAD) and to suggest the direction of future research. Methods We searched papers in Pubmed database to use some keywords indicating whiplash injury syndrome, treatment of Korean Medicine and cost-effectiveness. After searching, appropriate papers were selected depending on the exclusion criteria. The selected papers were analyzed in the sections of author, publication year, intervention and control groups, outcome measurement, the list including in the cost, cost-effectiveness, cost-utility and study design. Results Four studies about effect of Korean medicine and 3 studies about economic evaluation were finally included. Acupuncture was effective for balance disorder and neck pain. Economic evaluation studies used analytical decision model or cost-consequence analysis. Cost-effectiveness analysis using visual analog scale and cost-utility analysis using quality adjusted life years were performed. Initiating timing of proper management affected the consequence of treatments. Direct and indirect medical costs including supportive devices, and non-medical costs such as litigation were considered. Conclusions We conclude that studies haven't been conducted so far to evaluate the cost-effectiveness of Korean Medicine in whiplash injury syndrome. Thus, future studies are needed in this section.

가상현실을 이용한 모아간호 실습교육이 간호 대학생의 실습역량에 미치는 영향: 체계적 문헌고찰 (The effects of maternal-child nursing clinical practicum using virtual reality on nursing students' competencies: a systematic review)

  • 황성우;김현경
    • 여성건강간호학회지
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    • 제28권3호
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    • pp.174-186
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    • 2022
  • Purpose: This study aimed to investigate the effects of virtual reality used in maternal-child nursing clinical practicums on nursing students' competencies through a systematic review. Methods: The inclusion criteria were peer-reviewed papers in English or Korean presenting analytic studies of maternal-child nursing practicums using virtual reality. An electronic literature search of the Cochrane Library, CINAHL, EMBASE, ERIC, PubMed, and Research Information Sharing System databases was performed using combinations of the keywords "nursing student," "virtual reality," "augmented reality," "mixed reality," and "virtual simulation" from February 4 to 15, 2022. Quality appraisal was performed using the RoB 2 and ROBINS-I tools for randomized controlled trials (RCTs) and non-RCTs, respectively. Results: Of the seven articles identified, the RCT study (n=1) was deemed to have a high risk of bias, with some items indeterminable due to a lack of reported details. Most of the non-RCT studies (n=6) had a moderate or serious risk of bias related to selection and measurement issues. Clinical education using virtual reality had positive effects on knowledge, skills, satisfaction, self-efficacy, and needs improvement; however, it did not affect critical thinking or self-directed learning. Conclusion: This study demonstrated that using virtual reality for maternal-child nursing clinical practicums had educational effects on a variety of students' competencies. Considering the challenges of providing direct care in clinical practicums, virtual reality can be a viable tool that supplements maternal-child nursing experience. Greater rigor and fuller reporting of study details are required for future research.

Initial assessment of hemorrhagic shock by trauma computed tomography measurement of the inferior vena cava in blunt trauma patients

  • Lee, Gun Ho;Choi, Jeong Woo
    • Journal of Trauma and Injury
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    • 제35권3호
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    • pp.181-188
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    • 2022
  • Purpose: Inferior vena cava (IVC) collapse is related to hypovolemia. Sonography has been used to measure the IVC diameter, but there is variation depending on the skill of the operator and it is difficult to obtain accurate measurements in patients who have a large amount of intestinal gas or are obese. As a modality to obtain accurate measurements, we measured the diameters of the IVC and aorta on trauma computed tomography scans and investigated the correlation between the IVC to aorta ratio and the shock index in blunt trauma patients. Methods: We retrospectively analyzed the medical records of 588 trauma patients who were transferred to the regional trauma center (level 1) of Wonkang University Hospital from March 2020 to February 2021. We included trauma patients 18 years or older who met the trauma activation criteria and underwent trauma computed tomography scans with intravenous contrast within 40 minutes of admission. The shock index was calculated from vital signs before trauma computed tomography scan, and measurements of the anteroposterior diameter of the IVC (AP), the transverse diameter of the IVC (T), and aorta were made 10 mm above the right renal vein in the venous phase. Results: Overall, 271 patients were included in this study, of whom 150 had a shock index ≤0.7 and 121 had a shock index >0.7. The T to AP ratio and AP to aorta ratio were significantly different between groups. Cutoffs were identified for the T to AP ratio and AP to aorta ratio (2.37 and 0.62, respectively) that produced clinically useful sensitivity and specificity for predicting a shock index >0.7, demonstrating moderate accuracy (T to AP ratio: area under the curve, 0.71; sensitivity, 59%; specificity, 87% and AP to aorta ratio: area under the curve, 0.70; sensitivity, 55%; specificity, 91%). Conclusions: The T to AP ratio and AP to aorta ratio are useful for predicting hemorrhagic shock in trauma patients.

머신러닝 기반 음성분석을 통한 체질량지수 분류 예측 - 한국 성인을 중심으로 (Application of Machine Learning on Voice Signals to Classify Body Mass Index - Based on Korean Adults in the Korean Medicine Data Center)

  • 김준호;박기현;김호석;이시우;김상혁
    • 사상체질의학회지
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    • 제33권4호
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    • pp.1-9
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    • 2021
  • Objectives The purpose of this study was to check whether the classification of the individual's Body Mass Index (BMI) could be predicted by analyzing the voice data constructed at the Korean medicine data center (KDC) using machine learning. Methods In this study, we proposed a convolutional neural network (CNN)-based BMI classification model. The subjects of this study were Korean adults who had completed voice recording and BMI measurement in 2006-2015 among the data established at the Korean Medicine Data Center. Among them, 2,825 data were used for training to build the model, and 566 data were used to assess the performance of the model. As an input feature of CNN, Mel-frequency cepstral coefficient (MFCC) extracted from vowel utterances was used. A model was constructed to predict a total of four groups according to gender and BMI criteria: overweight male, normal male, overweight female, and normal female. Results & Conclusions Performance evaluation was conducted using F1-score and Accuracy. As a result of the prediction for four groups, The average accuracy was 0.6016, and the average F1-score was 0.5922. Although it showed good performance in gender discrimination, it is judged that performance improvement through follow-up studies is necessary for distinguishing BMI within gender. As research on deep learning is active, performance improvement is expected through future research.

시판 배추김치의 나트륨 함량 모니터링 (Monitoring of Sodium Content in Commercial Baechu (Kimchi Cabbage) Kimchi)

  • 문은우;이희민;김성현;서혜영
    • 한국식품영양학회지
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    • 제35권6호
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    • pp.537-542
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    • 2022
  • This study was conducted to provide basic data on the amount of sodium and the setting of permissible error range of actual measurement, which is a problem for cabbage kimchi nutrients subject to labeling. The sample targeted was baechu (Kimchi cabbage) kimchi, which might have a large variation in sodium content by part of kimchi. Kimchi samples were collected twice from eight companies by season (spring, summer, fall, and winter). The average sodium content in kimchi samples was 619±87 mg/100 g (range, 534±63 mg/100 g to 783±40 mg/100 g). The error in average annual sodium content of abandonment kimchi (maximum value difference compared to the minimum value) was 26.8 to 64.3%. Sodium contents in kimchi produced in spring and summer were relatively low. However, deviation between individuals was large. It was found that cases exceeding the permissible error (120%) standard varied depending on the criteria for setting the amount of sodium. In addition, due to seasonal differences, sodium content in kimchi exceeded 120% of the labeling value. Thus, it is necessary to set standards suitable for characteristics of kimchi to prevent unintentional violations of labeling standards by raw materials and manufacturing processes.

노인에서 머리회전을 동반한 보행이 보행변수에 미치는 영향 (Effects of the Head-Turn Gait on Gait Parameters in the Elderly)

  • 이명희;장종성
    • PNF and Movement
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    • 제19권3호
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    • pp.435-440
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    • 2021
  • Purpose: The purpose of this study is to investigate the effects of older adult's head-turn gait on gait parameters by comparing with head oriented forward gait and to provide criteria for their risk of falling compared to young adult. Methods: The subjects were 19 young adults in their 20s and 18 older adults in their 60s or above residing in Daegu or Gyeongsangbuk-do. To evaluate their gait parameters, spatiotemporal gait parameters were measured using a gait analysis tool (Legsys, BioSensics, USA) under two conditions: 1) walking while keeping one's eyes forward and 2) walking while turning the head. The measurement for each test was performed after one practice session, and the mean value of three measurements was analyzed. The collected data were statistically processed using a two-way analysis of variance (ANOVA) to compare any differences in gait parameters between the two groups under the two conditions. The statistical significance level was set at α=0.05. Results: According to the comparison of gait parameters in young adult and older adult between the head oriented forward gait and head-turn gait, statistically significant differences were observed in two parameters: stride length according to the height ratio and stride speed obtained by dividing the stride length according to the height ratio by time (p<0.05). Conclusion: The results of this study indicate that the head-turn gait causes greater differences in stride length and speed among older adult than in young adult and therefore can act as a cause of falling.