• Journal of IKEEE
• /
• v.24 no.2
• /
• pp.638-648
• /
• 2020

Currently, the method of user-follwoing in intelligent cooperative robots usually based in vision system and using Lidar is common and have excellent performance. But in the closed space of Corona 19, which spread worldwide in 2020, robots for cooperation with medical staff were insignificant. This is because Medical staff are all wearing protective clothing to prevent virus infection, which is not easy to apply with existing research techniques. Therefore, in order to solve these problems in this paper, the ultrasonic sensor is separated from the transmitting and receiving parts, and based on this, this paper propose that estimating the user's position and can actively follow and cooperate with people. However, the ultrasonic sensors were partially applied by improving the Median filter in order to reduce the error caused by the short circuit in communication between hard reflection and the number of light reflections, and the operation technology was improved by applying the curvature trajectory for smooth operation in a small area. Median filter reduced the error of degree and distance by 70%, vehicle running stability was verified through the training course such as 'S' and '8' in the result.

• Journal of Preventive Medicine and Public Health
• /
• v.26 no.3 s.43
• /
• pp.371-386
• /
• 1993

This study was carried out to evaluate diagnostic criteria of noise-induced hearing loss (NIHL) among-workers in an iron foundry. Of 1,093 workers under the observation of noise-specific health examination, 184 workers were selected by way of first and second screening audiometric examination. A questionnaire survey, otological examinations, Rinne test and audiometric test were performed and the results were as follows ; The degree of hearing impairment in the left ear was more severe than in the right ear (p<0.05). The difference between hearing threshold of the first and the second hearing test at 1,000 Hz was about 5 dB with a narrow range of deviations while the difference at 4,000 Hz was about -7 dB with a wide range. Of the total study workers, 84.8% were tested within 15 hours away from noise exposure, and the rest after 16 hours. This study has identified that mean hearing loss at 4,000 Hz showed a significant statistical difference among the two study groups while mean hearing loss by 4-divided classification did not. The same phenomena were observed between the group with and without tinnitus and between the group with and without difficulty in hearing (p<0.05). Among 184 workers, 10 workers (5.4%) diagnosed as NIHL by old diagnostic criteria in contrast to 150 workers diagnosed as NIHL by the new diagnostic criteria. There was a significant difference between the two groups in the average hearing loss at 4,000 Hz and 4-divided classification (p<0.01), but there were no significant differences in age, the duration of employment, blood pressure and the duration wearing the personal hearing protector (p>0.05). If we apply Early Loss Index (ELI) method, some workers in younger age group diagnosed as NIHL by the new diagnostic criteria were fallen into within the normal range. In the mean time older age group show reverse results in contrast to the above finding. It is too early to confirm the value of the usage of the new diagnostic criteria in hearing examination. Further study is called for to verify the value of this criteria.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.16 no.3 s.43
• /
• pp.181-195
• /
• 1992

The purposes of this study were to investigate 1) the effect of body exposure and color of a woman's suit on the perception of modesty, and 2) the effect of perceiver's sex and age on impression formed by the function of clothing variables. The instrument of this study consisted of a response scale and stimuli. Thirteen items of 7-point semantic differential scales were developed to measure the perceiver's impression on wearer's modesty. Stimuli were color pictures of a model wearing one of 8 types of suit constructed by a 2 $\times$ 2 $\times$ 2 factorial design. The manipulation of each level of the clothing variables were: color of the suit by black and red, leg exposure by varying skirt lengths to a Chanel-line and mini skirt, and neck exposure by shirt collar blouse and scarf. Two models, representing typical female college students living in Seoul, were selected to eliminate model effect. The sample include 384 subjects, consisting of 4 groups of male and female college students and middle aged men and women. Eight experimental groups were randomly assigned to one of eight stimuli based on between-subject design. One half of each group responded to model 1 and the other half to model 2 of same stimulus. Responses to the semantic differential scales were factor analyzed (pc model, Varimax rotation) to identify factors constructing impression of modesty. Two factors emerged regard­less of subgroups; Elegance and Extroversion factor. The first factor was found to be dominant, accounting for 60 percent of the total variance. The other accounted for just 11 percent. Multidimensional ANOVA (5-way, 3-way) was conducted to test the effect of the clothing variables against two factors identified from the factor analysis. Leg exposure was the most powerful variable affecting the impression of Elegance and Extroversion factor for all per. ceiver subgroups. Neck exposure had primary effect on the impression of Elegance, whereas it partially influenced that of Extroversion. Color of suit had only partial effect on the impression of Extroversion. Hypothesis I was partially supported from the findings above. The effect of perceiver's age and sex on impression by the function of clothing variables was tested by comparing the result between four subgroups. In forming an impression of the wearer's modesty, male college students were least affected by the manipulation of clothing variables, while middle aged males were affected most. In the female groups, there was no age difference and they fell between the male groups in the degree to which they were affected. Hypothesis II was supported only by age difference in two male groups, and by sex difference in two student groups.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.28 no.5
• /
• pp.582-590
• /
• 2004

The purpose of this study was to evaluate thermal properties of Taekwondo wears with three different materials. As a begging step, the questionnaire survey about the actual condition of Taekwondo wears was conducted. With the results of the questionnaire, cotton/nylon(70/30) blended fabric(CN) that was newly woven with sweat absorbent finishing and cotton/spandex(95/5) blended fabric with flexibility property were developed. The same designed 3 Taekwondo wears with 3 different materials which were two different materials(CN and CS) and a current material(cotton/PET, CP) were made. Four young males volunteered for this study, they kicked and punched as Taekwondo action for 20 minutes. Mean skin temperature was the highest in CS(33.1${\pm}$0.8$^{\circ}C$) and the lowest in CP(32.7${\pm}$0.6$^{\circ}C$). Increasing degree of rectal temperature didn't show any significant difference. Clothing microclimate temperature on the thigh was higher in CS(32.8${\pm}$17.4$^{\circ}C$) than in CN(29.4${\pm}$1.1$^{\circ}C$) and CP(29.4${\pm}$1.0$^{\circ}C$). Clothing microclimate temperature on the back and humidity on the thigh didn't show any significant differences. Clothing microclimate humidity on the back was higher in CP(65${\pm}$20%RH) than in CS(61${\pm}$17％RH). Heart rate, total body weight loss, and local sweating were not significantly different by materials. Most subject responded more hot in CN than in others, but there were no significant differences at the subjective sensation of thermal humidity. They answered more comfortable in CN than in others. Tectile sensations were the best in CN and the worst in CS. From those results, first of all, it is necessary to be weighted on Taekwondo wears made of CN in the aspects of the dignity of military arts uniform. Secondly, CS was required to be lighted and enhanced for the subjective sensation. Third, CP weaved honey comb was asked more various design to eliminate sweat high competition power within the scope of the dignity of military arts uniform.

• Journal of Korean Ophthalmic Optics Society
• /
• v.17 no.4
• /
• pp.381-388
• /
• 2012

Purpose: In this study, the changes in the shape of silicone hydrogel lenses, dryness of lens and objective/ subjective symptoms that could be induced by repeating dryness of lens and objective/subjective symptoms were investigated. Methods: After drying and rehydrating of silicone hydrogel lenses with different lens material and thickness for 4 times, their overall diameters and base curves were compared. Subjective symptoms, non-invasive tear break-up time (NIBUTs) and blinking rate were evaluated after wearing dehydrated silicone hydrogel lens. Results: Overall diameter and base curve increased in all tested silicone hydrogel lenses by repeating dryness and rehydration. The degree of change in over all diameter and base curve were variable on the material. There were irregular change of lens parameters in thicker lens. When the subjects wore silicone hydrogel lenses after drying and rehydrating, their NIBUTs were decreased and blink rates were increased regardless of lens material or thickness. In addition, repetitive drying of silicone hydrogel lenses affected the lens fitting. Therefore, subjective symptoms such as itching, pain, irritation, foreign body sensation, dryness tended to be increased. Conclusions: The results obtained from the study may suggest to develop durable silicone hydrogel contact lenses against dry environment since the changes in parameters of silicone hydrogel lens and the subjective discomfort were observed after repetitive drying and rehydration.

• The Journal of Korean Academy of Prosthodontics
• /
• v.19 no.1
• /
• pp.39-45
• /
• 1981

Distal-extension removable partial dentures have long been implicated in the increase in mobility and the destruction of the supporting structures of the primary abutment teeth. Various clasping systems have traditionally been used to retain distal extension removable partial dentures, and other designs have been proposed to minimize torquing forces on the abutment teeth. Most recent studies investigating the effects of removable partial dentures on abutment teeth have been performed in it laboratory setting. Results obtained from in vitro research have given dentists insight into removable partial denture design, but laboratory test model cannot be constructed that simulates actual functional or parafunctiona1 movements and forces. The purpose of this study was to clinically evaluate the degree of tooth mobility produced by two clasping systems (suprabulge type and infrabulge type) used for distal extension removable partial dentures. Akers clasp and R.P.I. system were selected for the evaluation, and four patients required a distal extension removable partial denture on the mandibular arch were selected for participation in the study. Two partial dentures were constructed in the same condition expect the design of clasp. All abutments in the study were mandibular first or second premolars. Measurements of mobility were made with a research tool designed by $M\"{u}hlemann$. This instrument, periodontometer, measures tooth mobility in the mouth by means of a dial gauge accurated to 0.01mm when the tooth is stressed with a force meter. Lingual and buccal deflection of abutment tooth was measured using buccal and lingual pressure. The amount of force applied was 500gm. Tooth mobility tests were made at four key stages; 1. Before insertion of the first removable partial denture, baseline mobility was establsihed. 2. After wearing of the first prosthesis, measurement was made at weekly intervals for 4 weeks. 3. The removable partial denture was then taken from the patient, and tooth mobility was measured again at weekly intervals until the patient's established baseline mobility had returned. 4. The second prosthesis of different clasp design was worn for a month and evaluated in the same manner as the first. The sequence of placement of clasping system was alternated between patients. The following results were obtained from this study; 1. The mobility of abutment tooth increased during the initial stage of wear and returned to baseline mobility after removal of removable partial dentures. 2. The mobility of abutment tooth showed no difference between Akers clasp and I-bar clasp during the 4-week test period. 3. All teeth tested showed greater mobility toward the buccal than the lingual direction.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.32 no.2
• /
• pp.146-152
• /
• 2022

Objectives: The purpose of this study is to confirm whether there is a factor to affect the evaluation of fit test of a 2nd class half masks using a OPC test method. Methods: Total 34 adults including Males and Females were tested using OPC-based fit testing equipment while wearing a 2nd class half filtered mask. Results: 1. The result of measuring face dimensions using different tools such as a 3D scanner and digital calipers revealed that the variation of lip width was not statistically significant because there was only a difference of about 4 mm. However, it showed that a difference in face length was statistically significant enough with 10 mm(p<0.000). 2. The fit factor for each exercise stage according to gender was the highest at 124.54(p<0.001) in Step 3, and the fit factor was the lowest at 73.75 in Step 1. 3. In the evaluation of the degree of fit factor according to gender, female passed 67.44%, which was higher than the value in male(p<0.038). 4. The acceptance rate of the group having a face length of shorter than 110 mm was 91.67%. On the other hand, the acceptance rate of the group with a face length of longer than 110 mm was 47.27%(p<0.000). 5. The fit test was possible because the fit factor with 2nd class half masks corresponding to FFP1(Filtering Face Piece 1) was passed 55% or more. Conclusions: The test results showed that using a 2nd class half filtered mask, it is important to wear a properly designed mask so that face size does not affect the fit factor.

• Annals of Occupational and Environmental Medicine
• /
• v.35
• /
• pp.24.1-24.15
• /
• 2023

Background: The construction workers are vulnerable to fatigue due to high physical workload. This study aimed to investigate the relationship between overwork and heart rate in construction workers and propose a scheme to prevent overwork in advance. Methods: We measured the heart rates of construction workers at a construction site of a residential and commercial complex in Seoul from August to October 2021 and develop an index that monitors overwork in real-time. A total of 66 Korean workers participated in the study, wearing real-time heart rate monitoring equipment. The relative heart rate (RHR) was calculated using the minimum and maximum heart rates, and the maximum acceptable working time (MAWT) was estimated using RHR to calculate the workload. The overwork index (OI) was defined as the cumulative workload evaluated with the MAWT. An appropriate scenario line (PSL) was set as an index that can be compared to the OI to evaluate the degree of overwork in real-time. The excess overwork index (EOI) was evaluated in real-time during work performance using the difference between the OI and the PSL. The EOI value was used to perform receiver operating characteristic (ROC) curve analysis to find the optimal cut-off value for classification of overwork state. Results: Of the 60 participants analyzed, 28 (46.7%) were classified as the overwork group based on their RHR. ROC curve analysis showed that the EOI was a good predictor of overwork, with an area under the curve of 0.824. The optimal cut-off values ranged from 21.8% to 24.0% depending on the method used to determine the cut-off point. Conclusion: The EOI showed promising results as a predictive tool to assess overwork in real-time using heart rate monitoring and calculation through MAWT. Further research is needed to assess physical workload accurately and determine cut-off values across industries.

• The Journal of the Acoustical Society of Korea
• /
• v.43 no.4
• /
• pp.422-435
• /
• 2024

This study intended to verify the effects of face masks on the Korean language in terms of acoustic, aerodynamic, and formant parameters. We chose all types of face masks available in Korea based on filter performance and folding type. Two professional voice actors (a male and a female) with more than 20 years of experience who are native Koreans and speak standard Korean participated in this study as speakers of voice data. Face masks attenuated the high-frequency range, resulting in decreased Vowel Space Area (VSA) and Vowel Articulation Index (VAI)scores and an increased Low-to-High spectral ratio (L/H ratio) in all voice samples. This can result in lower speech intelligibility. However, the degree of increment and decrement was based on the voice characteristics. For female speakers, the Speech Level (SL) and Cepstral Peak Prominence (CPP) increased with increasing face mask thickness. In this study, the presence or filter performance of a face mask was found to affect speech acoustic parameters according to the speech characteristics. Face masks provoked vocal effort when the vocal intensity was not sufficiently strong, or the environment had less reverberance. Further research needs to be conducted on the vocal efforts induced by face masks to overcome acoustic modifications when wearing masks.

• Korean Journal of Occupational Health Nursing
• /
• v.6 no.2
• /
• pp.110-127
• /
• 1997

The aim of this study is to present the basic datum for the promotion of effectiveness and improvement of nursery tasks, by grasping the situation of operating room nurses tasks and the degree of their fatigue. For these researches, 70 nurses out of the operating rooms of 3 university-affiliated hospitals-two in Seoul and one in Pusan, were chosen at random by a non-probability sampling method. These researches were done from April 14 to April 26 in 1997 by questionairing method. The questionaire was composed of 30 items, which asks the examinees of their physical, mental, and neurosensory symptoms, with 10 items respectively. The reliability of the research instrument was turned out very high with Cronbach's ${\alpha}=.9376$. The datum were electronically processed using Statistics Program for Social Sciences(SPSS). The analysis of datum in this study has a general character, in which the demosociological character and the special ex-officio character was calculated by frequency and percentage. The situation of tasks in operating rooms was calculated by frequency and percentage. The fatigue of operating room nurses was calculated by average and standard deviation. To compare the fatigue with regard to the character of operating room nurse's tasks, t-test and F-test(ANOVA) were used after the character of variations, and the variations at the level of P<.05 which might have some meaning was verified after the fact with Duncan's Multiple Range(DMR). The results of this research are as follows : 1) The nurses working in operating rooms show their fatigue in three fields-in Group I physical symptoms 3.28, in Group III neurosensory symptoms 2.85, and in Group II mental symptoms 2.73, which shows I Dominant type (general type). 2) They complain, in Group I they are "feeling the heavy legs," 3.28 and in Group II they "occasionally forget soon what to do," 3.09. and in Group III, they "feel lumbago," 3.47, which is the highest rate of the three. The highest rate results from the character of their tasks, in which they have to move rapidly the heavy appliances and do their jobs standing many hours, especially wearing heavy radiation protector. 3) As to transportation, subway using group feel the greatest fatigue, 3.18(F=4.315, P=.008). 4) As to department, nurses in the orthopedic's surgery part feel the greatest fatigue, 3.26(F=2.040, P=.050). 5) As to the change of physical symptoms, the group answering that they found physical abnormality after working in operating rooms show the greatest fatigue, 3.12(t=-3.13, P=.003). 6) At to the general circumstances, the group answering that they receive insufficient consideration on their physical abnormality in their department, show the greatest fatigue, 3.10(F=3.200, P=0.47). 7) As to the relation with superior officers, the group answering that their superior officer has an impetuous temperament, show great fatigue, 3.11(F=4.855, P=.011). 8) As to the time of feeling fatigue, the fatigue reaches the highest point 1~2 hours after operations, 3.04(F=2.703, P=.046). 9) When they feel fatigue after scrub nurse duties, they feel the greatest fatigue 2 hours after the duties, 3.09( F=2.841, P=.038). 10) As to the operation instruments, when they use complex instruments borrowing from the outside in addition to the basic instruments, their fatigue becomes the greatest, 3.09(F=7.831, P=.000). 11) As to the kind of operation, when they participate in orthopedic's surgery operations, they feel the greatest fatigue, 3.18(F=4.362, P=.000). With the above results, it is proved that the degree of operating room nurses' fatigue is considerably high. So it may be concluded that the measure for lessening the fatigue should be find immediately, not on the level of personal matters but on the level of hospital nursing administration.