• Title/Summary/Keyword: impact test method

Search Result 1,264, Processing Time 0.028 seconds

Impact Resistance Testing of NK55 Ophthalmic Lenses in Domestic Market (국내 유통 NK55 재질 안경렌즈의 내충격 시험 평가)

  • Park, Mijung;Jeon, Inchul;Hwang, Kwang Hoon;Byun, Woongjin;Kim, So Ra
    • Journal of Korean Ophthalmic Optics Society
    • /
    • v.16 no.3
    • /
    • pp.229-235
    • /
    • 2011
  • Purpose: The present study was performed to evaluate the safety of ophthalmic lenses in domestic market since eyeglasses wearers could be exposed to the negligent accident by damaged ophthalmic lenses. Method: Totally, 160 ophthalmic lenses (NK55, ${n_{d}}$ = 1.56) with the refractive powers of -3D, -6D, +3D, +6D manufactured by 4 companies in domestic market were evaluated using drop ball test. In accordance with FDA standard, steel ball (~16 g) was freely dropped on these ophthalmic lenses from 127 cm high and the surfaces of lenses were observed. Results: From the study, center thicknesses of NK55 ophthalmic lenses manufactured by 4 different companies showed somewhat different numbers even though the lenses had the same refractive index and powers. All convex lenses of +3D, +6D were evaluated as the safe lenses since there was no damage such as crack and broken found on the lens surfaces after drop ball testing. However, some noticeable broken was shown on the surfaces of concave lenses with relatively thinner center thickness. Especially, 59(73.8%) of total 80 concave lenses with the refractive power of -3D and -6D classified as unacceptable lenses to FDA standard. Conclusions: From the results, the negligent accident by damaged ophthalmic lenses should be considered as well as the correction of visual acuity, design and price when customers purchase eyeglasses. Thus, the enforcement regulation like drop ball testing of uncut ophthalmic lens could be suggested to guarantee the safety of ophthalmic lenses in domestic market.

Primiparas만 Perceptions of Their Delivery Experience and Their Maternal-Infant Interaction : Compared According to Delivery Method (초산모의 분만유형별 분만경험에 대한 지각과 모아상호작용 과정에 관한 연구)

  • 조미영
    • Journal of Korean Academy of Nursing
    • /
    • v.20 no.2
    • /
    • pp.153-173
    • /
    • 1990
  • One of the important tasks for new parents. especially mothers, is to establish warm, mutually affirming interpersonal relationships with the new baby in the family, with the purpose of promoting the healthy development of the child and the wellbeing of the whole family. Nurses assess the quality of the behavioral characteristics of the maternal-infant interaction. This study examined the relationships between primiparas pereptions of their delivery experience and their maternal infant interaction. It compared to delivery experience of mothers having a normal vaginal delivery with those having a casearean section. The purpose was to explore the relationships between the mother's perceptions of her delivery experience with her maternal infant interaction. The aim was to contribute to the development of theoretical understanding on which to base care toward promoting the quality of maternal-infant interaction. Data were collected directly by the investigator and a trained associate from Dec. 1, 1987 to March 8, 1988. Subjects were 3 random sample of 62 mothers, 32 who had a normal vaginal delivery and 30 who had a non-elective cesarean section (but without other perinatal complications) at three general hospitals in Seoul. Instruments used were the Stainton Parent -infant Interaction Scale(1981) and the Marut and Mercer Perception of Birth Scale(1979). The first observations were made in the delivery room (for vaginally delivered mothers only), followed by day 1, day 2, day 3, and 2 weeks, 4 weeks, 6 weeks and 8 weeks after birth, for a total of 7-8 contacts(Cesarean section mothers were observed on days 4 and 5 but the data not used for analysis). Observations in the hospital were made during the hour prior to scheduled feedings. The infant was placed beside the mother. Later contacts were made at home. Data analysis was done by computer using as SPSS program and indulded X² test, paired t-test, t-test, and Pearson Correlation coefficient ; the results were as follows. 1. Mothers who had a normal vaginal delivery tended to perceive the delivery experience more positively than cesarean section mothers(p=0.002). The finding supported the hypothesis I that perception of delivery would vary according to the method of delivery. Mothers' perceptions of birth were classified into three dimensions, labor, delivery and the bady. There was a significantly different and positive perception by the vaginally delivered mothers to the delivery experience(p=0.000) but no differences for labor or the bady according to the delivery method(p=0.096, p=0.389), 2. Mothers who had a normal vaginal delivery had higher average maternal-infant interaction scores(p=0.029) than mothers who had a cesarean section. There were similar higher scores for the 1st day(p=0.042), 2nd day (p=0.009), and the 3rd day(p=0.006) after delivery but not for later times. The findings supported the hypothesis Ⅱ that there would be differences in maternal-infant interaction for mothers having vaginal and cesarean section deliveries. However these differences deccreased section deliveries. However these differences decreased over time . by eight weeks the scores for vaginal delivery mothers averaged 8.1 and for cesarean section mothers, 7.9. 3. The more highly positive the pereption of the delivery experience, the higher the maternal-infant interaction score for all subjects(F=.3206, p=.006). The findings supported the hypothesis Ⅲ that there would be correlations between perceptions of delivery and maternal-infant interaction. The maternal infant interaction was highest when the perception of the bady and deliery was positive(r=.4363, p=.000, r=.2881, p=.012). No correlations between perceptions of labor and maternal-infant interaction were found(p=0.062). 4. The daily maternal-infant interaction score for the initial contact after birth to 8 weeks postpartum had the lowest average score 5.20 and the highest 7.98(in a range of 0-10). This subjects group of mothers needed nursing intervention to promote their maternal- infant interaction. The daily scores for the maternal-infant over the period of eight weeks. However, there were significantly different increases in maternal-infant interaction only from the first to second day(p=0.000) and from the fourth to sixth weeks after birth(P=0.000). 5. When the eight items of maternal-infant interaction were evaluated separately, “Expresses feelings about her role as mother” had the highest average score, 1.64(ina range of 0-3)and “Speaks to baby” the lowest, 0.9. All items, with the possible exception of “Expresses feelings about her role as mother”, suggested the subjects' need of nursing intervention to promote maternal-infant interaction. 6. There were positive correlations between certain general charateristis, namely, both a higher economic status(p=0.002) and breast feeding(p=0.202) and maternal - infant interaction. There were positive correlations between a mother's confidence in her role as a mother and the perception of the birth experience(p=0.004). For mothers who had a cesarean section, a positive perception of the birth experience was related to the duration of her marriage(p=0.010), a wanted pregnancy (P=0.030) and her confidence in her role as a mother(p=0.000). Pereptions of birth for mothers who had a normal vaginal delivery were positive than those for mothers who had a cesarean section. The level of maternalinfant interaction for mothers delivered vaginally was higher than for cesarean section mothers. The relationship between perception of birth and materanalinfant interaction was confirmed. Cesarean section has an impact on the mother's perceived experience of birth which, in turn, is positively related to maternal-infant in turn, is positively related to maternal-infant interaction. Nursing intervention to enhance maternal-infant interaction should begin in prenatal classes with an exploration of the potential impact of cesarean section on the perceptions of the birth experience and continue throughout the perinatal and post-natal periods to promote the mother's ability to control with this crisis experience and to mobilize social support. Nursing should help transform a relatively negatively perceived experience into an accepted, positively perceived and self affirming experience which enhances the maternal-infant relationship.

  • PDF

Analysis of Counting Rate according to Presence or Absence of Detector's Protector in Beta-rays Measurement using Geiger-Muller Counter (Geiger-Muller 계수관을 이용한 베타선측정에서 디텍터 보호유무에 따른 계수율 분석)

  • Jang, Ji-Yong;Jeong, Moon-Taeg;Song, Jong-Nam;Ha, Jae-Jun;Han, Jae-Bok
    • Journal of the Korean Society of Radiology
    • /
    • v.12 no.1
    • /
    • pp.31-37
    • /
    • 2018
  • In the surface contamination test using the end-window Geiger-Muller type counter, the wrap is used as a method for protecting the detector exposed to the outside in order to measure the beta-rays. We analyze the effect of this method on the measurement rate and the correction factor, and wanted to make it clear to radiation workers that excessive use of the wrap can affect the measured value of the beta-rays. The experimental method was to compare and analyze the change of the beta-rays measurement counting rate and the calibration factor according to the wrap thickness using the beta-rays with different energy of 3 KBq, 1.5 KBq and 0.3 KBq. The subjects of this study were the end-window Geiger-Muller type counter which were held at the calibration center certified by Korea Laboratory Accreditation Scheme (KOLAS) in March 2012, Cl-36 (Chlorine) and Sr-90 (Strontium) were used as the source of beta radiation. The measurement counting rate decreased with increasing wrap thickness, and the calibration factor increased with increasing wrap thickness. Since the changes of the measurement counting rate and the calibration factors can reduce the accuracy of the instrument readings, but also have a significant impact on detector contamination and damage, so there is a need to find out what thickness of wrap is most effective. If we using a wraps with thickness that show a low rate of change of the measurement counting rate and the calibration factor, it will protect the detector and minimize the effect on the measured value of the beta-rays.

Compromised feature normalization method for deep neural network based speech recognition (심층신경망 기반의 음성인식을 위한 절충된 특징 정규화 방식)

  • Kim, Min Sik;Kim, Hyung Soon
    • Phonetics and Speech Sciences
    • /
    • v.12 no.3
    • /
    • pp.65-71
    • /
    • 2020
  • Feature normalization is a method to reduce the effect of environmental mismatch between the training and test conditions through the normalization of statistical characteristics of acoustic feature parameters. It demonstrates excellent performance improvement in the traditional Gaussian mixture model-hidden Markov model (GMM-HMM)-based speech recognition system. However, in a deep neural network (DNN)-based speech recognition system, minimizing the effects of environmental mismatch does not necessarily lead to the best performance improvement. In this paper, we attribute the cause of this phenomenon to information loss due to excessive feature normalization. We investigate whether there is a feature normalization method that maximizes the speech recognition performance by properly reducing the impact of environmental mismatch, while preserving useful information for training acoustic models. To this end, we introduce the mean and exponentiated variance normalization (MEVN), which is a compromise between the mean normalization (MN) and the mean and variance normalization (MVN), and compare the performance of DNN-based speech recognition system in noisy and reverberant environments according to the degree of variance normalization. Experimental results reveal that a slight performance improvement is obtained with the MEVN over the MN and the MVN, depending on the degree of variance normalization.

A Study on the Effective Method to Producing Data for The ROKA Live Fire Training Range Safety (한국군 실 사격 훈련간 효율적인 안전지대 데이터 구축 방안 연구)

  • Lee, June-Sik;Choi, Bong-Wan;Oh, Hyun-Seung
    • Journal of Korean Society of Industrial and Systems Engineering
    • /
    • v.38 no.3
    • /
    • pp.64-77
    • /
    • 2015
  • An effective method for produce munitions effectiveness data is to calculate weapon effectiveness indices in the US military's Joint Munitions Effectiveness Manuals (JMEM) and take advantage of the damage evaluation model (GFSM) and weapon Effectiveness Evaluation Model (Matrix Evaluator). However, a study about the Range Safety that can be applied in the live firing exercises is very insufficient in the case of ROK military. The Range Safety program is an element of the US Army Safety Program, and is the program responsible for developing policies and guidance to ensure the safe operation of live-fire ranges. The methodology of Weapon Danger Zone (WDZ) program is based on a combination of weapon modeling/simulation data and actual impact data. Also, each WDZ incorporates a probability distribution function which provides the information necessary to perform a quantitative risk assessment to evaluate the relative risk of an identified profile. A study of method to establish for K-Range Safety data is to develop manuals (pamphlet) will be a standard to ensure the effective and safe fire training at the ROK military education and training and environmental conditions. For example, WDZs are generated with the WDZ tool as part of the RMTK (Range Managers Tool Kit) package. The WDZ tool is a Geographic Information System-based application that is available to operational planners and range safety manager of Army and Marine Corps in both desktop and web-based versions. K-Range Safety Program based on US data is reflected in the Korean terrain by operating environments and training doctrine etc, and the range safety data are made. Thus, verification process on modified variables data is required. K-Range Safety rather than being produced by a single program, is an package safety activities and measures through weapon danger zone tool, SRP (The Sustainable Range Program), manuals, doctrine, terrain, climate, military defence M&S, weapon system development/operational test evaluation and analysis to continuously improving range safety zone. Distribution of this K-range safety pamphlet is available to Army users in electronic media only and is intended for the standing army and army reserve. Also publication and distribution to authorized users for marine corps commands are indicated in the table of allowances for publications. Therefore, this study proposes an efficient K-Range Safety Manual producing to calculate the danger zones that can be applied to the ROK military's live fire training by introducing of US Army weapons danger zone program and Range Safety Manual

Research on Impact Sensors for Developing the Electronic Body Protector of Taekwondo (태권도 전자호구 개발을 위한 충격감지 센서 연구)

  • Ki, Jae-Sug;Jeong, Dong-Hwa;Lee, Hyun-Jun
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.20 no.4
    • /
    • pp.648-655
    • /
    • 2019
  • This paper proposes the differential development of a Taekwondo electronic body protector. For this development, the most suitable sensor system was selected after analyzing and testing various sensor methods (magnetic sensors, electric capacity sensors, contact switch sensors, and piezo-film sensors) that could be applied in the electronic body protector, the selected sensors were distributed to the body and feet to make a more precise hit score, unlike the existing system in which all sensors are centralized on the body. Furthermore, it aims to illuminate using a lightweight film-type piezoelectric sensor on the body protector. In the case of an existing electronic body protector, all sensors and network device were concentrated on the body protector, so users need to purchase a set if they want it. On the other hand, the proposed system cloud can be used individually using a smart scoring WEP program. The effects of decreasing weight by up to 20% were compared with those of the existing system. Setting up a test facility is very difficult, so more study will be needed to analyze the effects of a hit.

Development of PSC I Girder Bridge Weigh-in-Motion System without Axle Detector (축감지기가 없는 PSC I 거더교의 주행중 차량하중분석시스템 개발)

  • Park, Min-Seok;Jo, Byung-Wan;Lee, Jungwhee;Kim, Sungkon
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.28 no.5A
    • /
    • pp.673-683
    • /
    • 2008
  • This study improved the existing method of using the longitudinal strain and concept of influence line to develop Bridge Weigh-in-Motion system without axle detector using the dynamic strain of the bridge girders and concrete slab. This paper first describes the considered algorithms of extracting passing vehicle information from the dynamic strain signal measured at the bridge slab, girders, and cross beams. Two different analysis methods of 1) influence line method, and 2) neural network method are considered, and parameter study of measurement locations is also performed. Then the procedures and the results of field tests are described. The field tests are performed to acquire training sets and test sets for neural networks, and also to verify and compare performances of the considered algorithms. Finally, comparison between the results of different algorithms and discussions are followed. For a PSC I-girder bridge, vehicle weight can be calculated within a reasonable error range using the dynamic strain gauge installed on the girders. The passing lane and passing speed of the vehicle can be accurately estimated using the strain signal from the concrete slab. The passing speed and peak duration were added to the input variables to reflect the influence of the dynamic interaction between the bridge and vehicles, and impact of the distance between axles, respectively; thus improving the accuracy of the weight calculation.

Effect of the Ayres Sensory Integration Intervention on the Motor Skills and Occupation Participation of Preschool Children with Attention-Deficit/Hyperactivity Disorder (Ayres의 감각통합중재가 학령전기 주의력결핍 과잉행동장애(ADHD) 성향 아동의 운동기능 및 작업참여에 미치는 영향)

  • Jung, Yun-Jin;Kang, Je-wook;Chang, Moon-young;Kim, Kyeong-Mi
    • The Journal of Korean Academy of Sensory Integration
    • /
    • v.22 no.1
    • /
    • pp.1-14
    • /
    • 2024
  • Objective : This study aimed to investigate the impact of Ayres' sensory integration (ASI) intervention on motor skills and occupational participation of preschool children with attention-deficit/hyperactivity disorder (ADHD). Method : Children with ADHD aged between 4 and 6 years who met the inclusion and exclusion criteria were randomly recruited through screening tests. The subjects were divided into an experimental group (10 subjects) and a control group (8 subjects). The instruments used were the Bruininks-Oseretsky test of motor proficiency-2 (BOT-2), Pediatric Evaluation of Disability Inventory (PEDI), and Goal Attainment Scale (GAS) to evaluate occupational participation. The subjects in the experimental group underwent individual sensory integration therapy according to the ASI principles for 40 minutes twice a week in a total of 16 sessions over eight weeks. The control group did not receive the ASI intervention. Data analysis was performed using the Mann-Whitney U test, chi-squared test, Wilcoxon signed-rank test, and Cohen's d test in SPSS 20.0. Results : The ASI experimental group had significantly higher scores in total motor composite, manual coordination, body coordination, strength, and agility in motor function than the control group (p<.05). The two groups did not differ significantly in terms of occupational participation (PEDI), but GAS scores for individual target activities were significantly higher in the experimental group than in the control group (p<.05). Conclusion : This study shows that the ASI intervention has positive effects on motor skills and occupation participation among preschool children with ADHD.

The Study on the Physical Property of Provisional Prosthesis using Modified Temporary Abutment (변형된 임플란트 임시 지대주의 물성에 대한 연구)

  • Yang, Byung-Duk;Yoon, Tae-Ho;Choi, Un-Jae;Park, Ju-Mi
    • Journal of Dental Rehabilitation and Applied Science
    • /
    • v.22 no.4
    • /
    • pp.329-340
    • /
    • 2006
  • Statement of problem: Damping of the peak force transmitted to implants has been reported by in vitro studies using impact forces on resin-veneered superstructures. Theoretical assumptions suggest that use of acrylic resin for the occlusal surfaces of a prosthesis would protect the connection between implant and bone. Therefore, the relationship between prosthesis materials and the force transmitted through the implant system also needs to be investigated under conditions that resemble the intraoral mechanical environment. Purpose: The purpose of this study was to analyze the fracture strength and modes of temporary prosthesis when a flange or occlusally extended structure were connected on the top of the abutment. Material and method: Modified abutments of winged and bulk design were made by casting the desired wax pattern which is made on the UCLA type plastic cylinder. Temporary crowns were made using templates on the modified abutments, and its fracture toughness and strain were compared to the traditional temporary prosthesis. To evaluate the effect of aging, 5.000 times of thermocycling were performed, and their result was compared to the 24hours specimen result. Results: The following conclusions were drawn from this study: 1. In the fracture toughness test, temporary crown's fracture line located next to the screw hole while modified designs with metal support showed fracture line on the metal and its propagation along the metal-resin interface. 2. Wing and bulk structure didn't show significant difference in the fracture toughness (p>0.05), but wing structure showed stress concentration on the screw hole area compared to bulk structure which showed even stress distribution. 3. In the fracture toughness test after thermocycling, wing and bulk structure showed increased or similar results in metal supported area while off-metal area and temporary crown showed decreased results. 4. In the strain measurement after thermocycling, its value increased in the temporary and bulk structure. However, wing structure showed decreased value in the loading point while increased value in the screw hole area. Conclusion: Wing type design showed compatible result to the bulk type that its application with composite resin prosthesis to the implant dentistry is considered promising.

Factors Influencing the Communication Skill for the Elderly of Dental Hygienist (치과위생사의 노인에 대한 의사소통능력에 영향을 미치는 요인)

  • Lim, Hee-Jung;Kim, Hyoung-Joo
    • The Journal of the Korea Contents Association
    • /
    • v.16 no.6
    • /
    • pp.627-635
    • /
    • 2016
  • The purpose of this study was to investigate the communication skill of a dental hygienist for the elderly. The self-administered questionnaire selected by convenience sampling method from January 2 to February 14, 2015, Seoul, Kyungki, Incheon regions final analysis section 233 to target dental hygienist working under a dentist institutions. This study analyzed collected data by t-test, ANOVA, pearson correlation coefficient, and multiple regression. According to multiple regression analysis results can be number of worker, the main task, living experience feelings adjusted variable, as a result work in the dental hospital(B=.292 SE=.074), more like the elderly preference(B=.282, SE=.141), the behavior of the elderly(B=-.223, SE=.043) found that the more positive the impact. Therefore, the more exposure for your understanding and the elderly relationships for the the elderly appeared to affect the communication skill necessary to develop training programs that can improve the communication skill of a dental hygienist and apply to be prepared for the coming aging society.