Hand Linkage System Formation Using CT Images

Xiaopeng Yang,Hayoung Jung(정하영),Heecheon You(유희천) 대한인간공학회 2021 대한인간공학회 학술대회논문집 Vol.2021 No.11

Objective: The aim of this study is to form a hand linkage system using computed tomography (CT) images. Background: A human hand linkage system is widely used in biomechanical modeling and ergonomic design to define hand segments and hand link lengths. However, an inappropriate linkage system is commonly constructed based on bone length data or bony landmark locations. Method: Hand skeletons of 15 male participants were reconstructed from CT images in 10 postures selected from a natural hand-closing motion. The wrist joint center was anatomically estimated as the intersection of the centerline of the metacarpal of the middle finger and the distal wrist crease. The remaining hand joint centers were kinematically estimated based on the relative motion between the distal bone segment and the proximal bone segment of a given joint. A hand linkage system was then formed by connecting the derived joint centers. Results: Fifteen hand linkage systems were generated with different hand sizes. Hand link lengths of different hand segments were calculated for each participant. Regression models for predicting hand link lengths using hand length as the independent variable were established. Furthermore, regression models for predicting the joint center coordinates of the thumb carpometacarpal (CMC) and the four finger metacarpophalangeal (MCP) joints using hand length or hand breadth were established. Our models showed higher R2 values and lower maximum standard errors than the existing models. Conclusion: With the proposed regression models, practitioners can efficiently establish a hand linkage system, given the hand length and hand breadth. Application: The findings of the present study can be applied to hand models for ergonomic design and biomechanical modeling.

핸드 드라이어의 위생

장제윤 ( Jeyoun Jang ),이종태 ( Jong Tae Lee ) 국군의무사령부 2018 대한군진의학학술지 Vol.49 No.1

Objectives; Paper towels, warm air hand dryers, jet air dryers and cloth towels are the most frequently used means of hand drying in public washrooms. The purpose of this study is to investigate the hygiene of hand dryers in the public washroom and to investigate the changes of total microorganism when using a paper towel or a hand dryer in the process of washing and desiccation the hands and the change of airborne bacteria in the toilet air by using a hand dryer in a general situation. Methods; The three hand dryers in washroom of Armed Forces Medical Research institute were used to assess the bacterial contamination. Bacterial contamination of the warm air hand dryer was evaluated by exposing air flows to petri dishes containing nutrient agar medium in a washroom. Identification of bacterial isolates was performed using conventional methods. Seven volunteers participated in the experiment to observe changes in bacterial colonies according to the drying method. The hands washed in a standardized manner. After hand drying, hand were pressed onto agar media and transfer of residual bacteria. There was significant difference between the after CPU between paper towel, air dryer. Results & Conclusions; Bacteria were found to be relatively numerous in the air flows. Bacterially contaminated air was found to be emitted whenever a warm air dryer was running, even when not being used for hand drying. Hot air from hand dryers can deposit pathogenic bacteria onto the hands and body of users. The risk of this bacteria to the general public not entirely clear, but they can be a risk factor for patients such as immunodeficiency. It is recommended therefore that the use of hand-dryers should be carefully considered on health grounds, especially in sensitive locations such as hospitals, catering establishments and food preparation areas. Guidelines for hygienic management of hand dryers should be provided for safe and hygienic hand dryer use.

자동차 조립라인에서 이중-헴머형(Double-hammer type) 임펙트 렌치와 오일-펄스형(Oil-pulse type)임펙트 렌치 에어공구의 국소진동가속도 및 소음수준

정재열,김정만 동아대학교 부설 산업의학연구소 1997 산업의학연구소 논총 Vol.- No.3

본 연구의 목적은 우리나라 산업발전 특히 자동차 생산량 증가에 따라 자동차의 대부분의 조립라인에서 많이 이용되고 있는 에어공구 중 이중-헴머형 임펙트 렌치와 오일-펄스형 임펙트 렌치를 대상으로 국소진동가속도 및 소음 수준 그리고 이에 영향을 주는 요인에 대한 공학적 연구를 하여 앞으로 국소 진동가속도 및 소음수준에 대한폭로 및 공학적 자료에 대한 기초자료를 제공하고자 자동차 조립라인(B/C 라인, TRIM 라인, 샷시 라인, 파이날 라인, 변속기 라인 등)에서 임펙트 렌치를 이용하는 작업자로 이중-헴머형(double-hammer type) 임펙트 렌치를 이용하는 작업자 34명, 오일-펄스형(oil-pulse type) 임펙트 렌치를 이용하는 작업자 31명을 대상으로 하여 작업시 오른손과 왼손에서 국소진동가속도 및 소음수준을 측정하였다. 또한 공정변수로 하루당 제품생산량, 단일공정에서 작업에 소요되는 시간, 볼트 또는 너트를 1 개 죄는데 소요되는 시간, 하루당 전체폭로시간, 단일공정에서 이용되는 볼트 또는 너트의 갯수 그리고 공구변수로 볼트 또는 너트의 용량, 분당공기소요량, 공구의 무게, RPM을 고려하였다. 연구결과를 요약하면 아래와 같다. 1. 오일-펄스형 임펙트가 볼트 또는 너트 1개를 죄는데 소요되는 시간이 2.19초로 헴머형 임펙트의 2.47초 보다 짧게 소요되었으나 볼트 또는 너트를 1 공정주기 동안에 죄는 갯수가 많아 하루당 전체폭로 시간이 높은 것으로 생각된다. 2. 오일-펄스형 임펙트 렌치는 이중-헴머형 임펙트 렌치보다 볼트 또는 너트의 용량이 클때 이용되는 경향이 있었고 RPM이나, 분당에어소요량이 많아 임펙트의 볼트 또는 너트를 이중-헴머형 임펙트 렌치로 1개를 죄는데 필요한 시간이 짧게 소요되는 것으로 생각된다. 오일-펄스 임펙트 렌치의 소음 수준이 이중-헴머형 임펙트 렌치의 소음수준보다 약 8dB(A)정도 낮았다. 3. 오른손에 대해 이중-헴머형 임펙트 렌치에서는 Zh축이 8.24m/sec², 오일-펄스형 임펙트 렌치에서는 Xh축이 2.59m/sec²으로 가장 높은 국소진동가속도수준은 나타냈다. 왼손에서는 이중-헴머형 임펙트 렌치의 Xh 축이 9.60m/sec², 오일-펄스형 임펙트 렌치에서는 Yh축이 3.23m/sec²으로 가장 높은 국소진동가속도수준을 나타냈다. 4. 이중-헴머형 임펙트 렌치에서는 Xh, Yh, Zh 3축에서 오른손보다 왼손에서 공히 국소진동가속도 수준이 높았으며, 오일-펄스형 임펙트 렌치에서는 Xh축에서는 오른손이 Yh축에서는 왼손이 Zh에서는 왼손이 높은 국소진동가속도수준을 나타냈다. 5. 이중-헴머형 임펙트 렌치와 오일-헴머형 임펙트 렌치에서 공히 3축 중 Y축의 왼손과 오른손의 국소진동가속도수준의 상관계수가 각각 0.76, 0.86으로 가장 관련성이 높은 것으로 제시되었다. 6. 반복성(repetitiveness)의 척도로서, 공정 1주기 동안에 볼트 또는 너트의 숫자에 대한 전체하루폭로시간을 표시하여 반복성과 진동폭로사이에 직접적인 상관관계를 볼 수 있었는데 공정 1주기 동안에 볼트 또는 너트의 갯수와 전체하루폭로시간에 대한 상관계수는 이중-헴머형 임펙트 렌치에서 0.84, 오일-펄스형 임펙트 렌치에서 0.50이었다. 7. 이중-헴머형 임펙트 렌치와 오일-펄스형 임펙트 렌치에서 전체가속도수준과 공구변수의 관계를 볼때, 오른손에서는 분당에어소요량, 왼손에서는 볼트 또는 너트의 용량이 공통적으로 설명력이 높은 변수이었다. 이중-헴머형 임펙트 렌치와 오일-펄스형 임펙트 렌치에서 소음에 대한 공구변수의 관계를 볼때, 분당공기소요량이 공통적으로 설명력이 높은 변수이었다. This study was conducted to introduce fundamental data of hand-arm vibration and noise exposure levels with impact wrenches(double-hammer impact wrenches and oil-pulse impact wrenches) used in automobile assembly lines considering the process variables and tool variables In studing, products per day, required time screwing the bolts or nuts per bolts or nut were considered as process variables, and capacity of bolts or nuts, air consumptions per minute, tool weights, RPM were considered as tool variables. Hand-arm vibration levels of 3 axis in each hand were measured using the instruments compling with ISO/DIS 5349 and noise levels were measured using a noise logging dosimeter. The results were as follows : 1. Required time to screwing the bolt or nut by oil-pulse impact wrenches is shorter than double-hammer impact wrenches but total daily exposure time of oil-pulse impact wrenches was higher than double-hammer impact wrenches because the number of bolts or nuts per cycle was many. 2. Oil-pulse impact wrenches have been used to screwing the large bolt or nut in comparing with double-hammer impact wrenches and required time to screwing the bolts or nuts were shorter than double-hammer impact wrenches because oil-pulse impact wrenches were using high RPM and large air consumption per minute. Noise level of oil-pulse impact wrenches was 8 dB(A) lower than double-hammer impact wrenches. 3. Dominant hand-arm vibration levels of double-hammer impact wrenches in each hand were 8.24 m/sec²of Zh axis in right hand and 9.60 m/sec²of Xh axis in left hand. Dominant hand-arm vibration level of oil-pulse impact wrenches in each hand was 2.59 m/sec²of Xh axis in right hand and 3.23 m/sec²of Yh axis in left hand. 4. In double-hammer impact wrenches, corresponding hand-arm vibration levels of Xh, Yh, Zh axis in left hand were higher than hand-arm vibration levels of right hand in 3 axis. In oil-pulse impact wrenches, Xh axis of right, Yh axis of left, Zh axis of left were higher than the corresponding hand-arm vibration levels of Xh, Yh, Zh axis in right and left hand. 5. Correlation coefficients among Xh, Yh, Zh axis of right and left hand hand-arm vibration levels in double-hammer impact wrenches and oil-pulse impact wrenches were commonly high in Yh axis and correlation coefficients of Yh axis in double-hammer impact wrenches and oil-pulse impact wrenches were 0.76 and 0.86, respectively. 6. As a measure repetitiveness, plotting total daily exposure time with the number of bolts or nut per cycle, direct correlation was shown between repetitiveness and hand-arn vibration exposure, and correlation coefficient between the number of bolts or nut per cycle and total daily exposure time in double-hammer impact wrenches, oil-pulse impact wrenches were 0.84 and 0.50, respectively. 7. Considering the total acceleration level and tool variables in double-hammer impact wrenches and oil-pulse impact wrenches, air consumption in right hand, and bolt or nut capacity in left hand were commonly the variable that explainability was high. Considering the noise and tool variables in double-hammer impact wrenches and oil-pulse impact wrenches, air consumption per minute was-commonly the variable that explainability was high.

손 기능 훈련이 손의 기민성에 미치는 영향

장철 ( Chel Jang ),이제영 ( Je Young Lee ),송민옥 ( Min Ok Song ) 대한통합의학회 2015 대한통합의학회지 Vol.3 No.4

Purpose : The purpose of this study was to provide the material about the treatment effect of hand function training and writing training being performed as a part of treatment to improve the function of the non-dominant hand of the patients whose dominant hand is damaged and thus need to improve their non-dominant hand``s function. Method : During one month of November, 2013, this study randomly chose five study subjects for hand function training, five for writing training, and ten of control group from 20 normal male and female adults going to K Univ. in Busan. All study subjects fully understood all of the training course, agreed to take the test in this study, and volunteered to participate in the test. Each training was performed five times for two weeks, 30 minutes each time. For measurement, Purdue pegboard was used to look into the change of hand dexterity. To investigate an improvement in hand function through hand function training and writing training, this study conducted early evaluation before training, interim evaluation, and final evaluation. Result : First, according to the comparison of dominant hand dexterity by group and by method during a training period, the groups of hand function training and of writing training improved dominant hand dexterity more than the control group. Secondly, according to the comparison of non-dominant hand dexterity by group during a training period, the groups of hand function training and of writing training improved dexterity more than the control group. According to the comparison of non-dominant hand dexterity by method during a training period, there was no big difference in dexterity between the groups of hand function training and of writing training and the control group. But, the group of hand function training showed a further improvement. Thirdly, according to the comparison of both-hand dexterity by group and by method during a training period, the groups of hand function training and of writing training improved both-hand dexterity more than the control group. Fourthly, according to the comparison of both-hand handling ability by group and by method during a training period, the groups of hand function training and of writing training improved both-hand handling ability more than the control group. Conclusion : Given the study result, it is considered that hand function training and writing training help brain damaged patients improve their hand function for their daily activity. And it will be meaningful to research brain damaged patients`` motor skills after their brain damage, and the patients who have low abilities of visual perception and cognition. In the future, it will be necessary to secure more study subjects and perform systematic training during a sufficient test period.

A Vision-Based Method to Find Fingertips in a Closed Hand

Chaudhary, Ankit,Vatwani, Kapil,Agrawal, Tushar,Raheja, J.L. Korea Information Processing Society 2012 Journal of information processing systems Vol.8 No.3

Hand gesture recognition is an important area of research in the field of Human Computer Interaction (HCI). The geometric attributes of the hand play an important role in hand shape reconstruction and gesture recognition. That said, fingertips are one of the important attributes for the detection of hand gestures and can provide valuable information from hand images. Many methods are available in scientific literature for fingertips detection with an open hand but very poor results are available for fingertips detection when the hand is closed. This paper presents a new method for the detection of fingertips in a closed hand using the corner detection method and an advanced edge detection algorithm. It is important to note that the skin color segmentation methodology did not work for fingertips detection in a closed hand. Thus the proposed method applied Gabor filter techniques for the detection of edges and then applied the corner detection algorithm for the detection of fingertips through the edges. To check the accuracy of the method, this method was tested on a vast number of images taken with a webcam. The method resulted in a higher accuracy rate of detections from the images. The method was further implemented on video for testing its validity on real time image capturing. These closed hand fingertips detection would help in controlling an electro-mechanical robotic hand via hand gesture in a natural way.

배양검사를 통해 확인한 중환자실 직원의 손씻기 효과

정재심,최정화,이순행,김양수 대한기초간호자연과학회 2003 Journal of korean biological nursing science Vol.5 No.2

The effect of hand hygiene was measured by hand culture before and after hand hygiene for 86 nurses, doctors, and nurses aide/housekeepers in Surgical Intensive Care Unit. The subjects were asked to press their dominant hand in hand-shaped Mannitol salt agar immediately after patient contact and then washed their hand by preferred hand hygiene agents [soap and water, waterless alcohol gel, or 4% chlorhexidine gluconate detergent(CHG)], and cultured one hand again. Amount of isolated microorganism was calculated by counting the number of divided areas(1 x 1cm) which is culture positive in hand culture plate. The amount of microorganisms were significantly reduced from 58.1(±38.59) to 27.4(±30.4) cells after hand hygiene. The staff nurse's hand hygiene was more effective compared to medical doctors and nurses aide/housekeepers. Methicillin-resistant Staphylococcus aureus(MRSA) was isolated in 41(47.1%) subjects ; but only removed 100% in 28(32.2%) subjects. When the amount of hand microorganisms was compared by subject's preferred hand hygiene agents, it was decreased in order of 4% CHG, waterless alcohol solution, soap and water, and water. The hand hygiene practice was inadequate to reduce hand microorganisms and significantly different by occupations. Further research and development of hand hygiene improvement program which emphasize the quality of hand hygiene is recommended.

Effect of Grip Training through Proto-type Silicone Dynamic Wrist Devices on Grip Strength and Wrist Flexor Tension in Chronic Stroke Patients

이대환,이중호 사단법인 미래융합기술연구학회 2021 아시아태평양융합연구교류논문지 Vol.7 No.12

The hand functions have very important roles in the patient's daily life, and if the hand strength is weak or muscle tension is abnormal, the patient has a major disability in moving the hand. If the tension of the hand muscle is too low, the patient cannot contract the muscle, and if the tension of the hand muscle is too high, the contraction of the muscle cannot be controlled by itself, and the movement of the joint cannot be made. Muscle tension in stroke patients increases over time and stiffness occurs, which eliminates joint movement. This study attempted to change muscle tension and increase muscle strength by performing hand grip training with a silicone dynamic wrist training mechanism. The subjects of this study were a total of 20 patients 6 months after stroke, and the effectiveness of a new hand training device was confirmed by measuring hand strength and modified ashworth scale (MAS). The general characteristics of the study subjects are that the average age was 60.32 ± 4.72 years, the average height was 168.53 ± 8.65 cm, and the average weight was 65.33 ± 11.23 kg. The average MMSE-K score was 27.23 ± 1.01. The increase in hand strength in chronic stroke patients was 2.80±1.52, which was statistically significant. In addition, the muscle tension changed from 2.60±0.65 to 2.33±0.59 and was statistically significant. The newly developed hand trainer is thought to have a positive effect on the improvement of hand function in patients with stroke.

성별 및 연령별 손 위생관리의 비교

김종규 한국환경보건학회 2019 한국환경보건학회지 Vol.45 No.3

Objective: This study was performed to evaluate gender and age differences in hygienic behavior among the general population, focusing on hand-washing habits and the microbial load of hands. Methods: A self-administered questionnaire survey and a separate microbial examination were performed. The Pearson’s correlation between hand-washing habits and microbial load was analyzed. Results: In the questionnaire survey on hand-washing habits, gender differences were found in hand-washing frequency, use of hand-washing agents, and hand drying methods (p<0.05). Age differences were found in numbers of washing parts of the hands and also in hand drying methods (p<0.05). Females showed better habits washing hands than did males, as did older people compared to younger. In the microbial examination of indicator bacteria on their hands, younger people tended to show a higher load of total aerobic bacteria than did the older, and females showed a higher load of total coliforms than did males (p<0.05). There were significant relationships between the load of total aerobic bacteria and hand-washing frequency, duration, and method of turning-off water (p<0.05). Conclusions: Although females were expected to show a better practice of hand-washing than were males based on the survey results, they showed a higher level of total coliforms in the hand examination. The older age group showed better hand-washing habits than did the younger age group and had less total aerobic bacteria on their hands. These inter-gender and age differences highlight the need for development and implementation of genderand age-specific educational programs or campaigns.

Comparative Study of Electromyography and Hand Elevation Test in Carpal Tunnel Syndrome

Yun, Tae Kyoung,Kim, Deok-Yeol,Ahn, Duck Sun The Korean Society for Microsurgery 2015 Archives of reconstructive microsurgery Vol.24 No.1

Purpose: Since the hand elevation test was first introduced by Ahn in 2001, it has been one of most performing provocative test for diagnosing carpal tunnel syndrome. Although many studies have been published on the hand elevation test, there are no study that can explain why false-negative results of hand elevation test appears in carpal tunnel syndrome patients diagnosed by electromyography (EMG) findings. Therefore we searched out whether hand elevation test is related with EMG severity. Materials and Methods: We made a retrospective study of 654 bilateral carpal tunnel syndrome patients. Among them 134 were studied which had different hand elevation test results on each hands. The paired samples t-test was used to compare the EMG severity of each group. The relationships between hand elevation test and EMG severity were examined using Pearson-product correlations. Comparing whether the frequency of false negative hand elevation were different between both hands, and whether the severity of EMG depends on which side of hand is, was evaluated with Mann-Whitney U-test. Results: Severity of EMG in positive group was moderate to severe on average, whereas mild to moderate on negative group, with significant difference statistically (p<0.001). Correlation between the hand elevation test results and EMG severity also showed significance statistically (p<0.001). Conclusion: Mild severity of EMG was found out to be the factor affecting the false results. However, EMG severity and hand elevation test shows a meaningful correlation, supporting the value of hand elevation test.

A Vision-Based Method to Find Fingertips in a Closed Hand

( Ankit Chaudhary ),( Kapil Vatwani ),( Tushar Agrawal ),( J L Raheja ) 한국정보처리학회 2012 Journal of information processing systems Vol.8 No.3

Hand gesture recognition is an important area of research in the field of Human Computer Interaction (HCI). The geometric attributes of the hand play an important role in hand shape reconstruction and gesture recognition. That said, fingertips are one of the important attributes for the detection of hand gestures and can provide valuable information from hand images. Many methods are available in scientific literature for fingertips detection with an open hand but very poor results are available for fingertips detection when the hand is closed. This paper presents a new method for the detection of fingertips in a closed hand using the corner detection method and an advanced edge detection algorithm. It is important to note that the skin color segmentation methodology did not work for fingertips detection in a closed hand. Thus the proposed method applied Gabor filter techniques for the detection of edges and then applied the corner detection algorithm for the detection of fingertips through the edges. To check the accuracy of the method, this method was tested on a vast number of images taken with a webcam. The method resulted in a higher accuracy rate of detections from the images. The method was further implemented on video for testing its validity on real time image capturing. These closed hand fingertips detection would help in controlling an electro-mechanical robotic hand via hand gesture in a natural way.