• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.961-965
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• 2000

This study aims to predict the particle size of blasted rock. For this purpose, Predicted particle sizes were compared with the measured particle sizes at the rock blasting sites, where various blasting patterns which controls the bench height, depth of blasted hole, burden, spacing etc were tested. the difference of mean fragment size between measured and predicted values was 0.11m.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.370-377
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• 2002

Generally, the system of calculation for the multi-path ultrasonic flow meters can be divided into two methods by how to get the mean velocity, namely, weighting and direct method. Weighting-method derive the mean velocity through modeling in theoretical velocity profile. Direct-method derive the mean velocity though actual flow distribution. The system of calculation varies with maker's transducer configuration and integration method. Each system has merits and demerits. This paper describes the system of integration that calculates line velocity over cross-section of the circular pipe. Flow rate mr discussed in this paper is a difference between theoretical flow rate and integrated flow rate according to values of Reynolds number in symmetric flow field or theoretical flow rate and integrated flow rate according to rotated model in asymmetric flow field.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.6
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• pp.745-750
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• 2005

Statement of problem. Resonance frequency analysis has been increasingly served as a non-invasive and objective method for clinical monitoring of implant stability. Many clinical studies must be required for standardized data using RFA. Purpose. This study was performed to evaluate RFA value changes in two anodized implant groups. Material and method. Among a total of 24 implants, twelve screw shaped implants as a test group (H2-R8.5) were manufactured, which had a pitch-height of 0.4 mm, an outer diameter of 4.3 mm, a length of 8.5 mm, and external hexa-headed, were turned from 5 mm rods of commercially pure titanium (ASTM Grade IV, Warantec Co., Seoul, Korea), and another twelve implants as a control group were $Br{\aa}nemark$ Ti-Unite MK4 (diameter 4.0 mm, length 8.5 mm). Each group was installed in tibia of rabbit. Two implants were placed in each tibia (four implants per rabbit). Test two implants were inserted in right side and control two in left side. ISQ values were measured using $Osstell^{TM}$ (Integration Diagnostics Ltd. Sweden) during fixture installation, and 12 weeks later and evaluated the RFA changes. Results. Mean and SD of baseline ISQ values of test group were $75.0{\pm}3.4$ and $68.7{\pm}8.1$ for control group. Mean and SO of ISQ values 12 weeks after implant insertion were $73.2{\pm}4.7$ for test group and $72.6{\pm}3.9$ for control group. There were no statistically significant differences between groups in ISQ values after 3 months (P>0.05). From the data, RFA gains after 3 months were calculated, and there was statistically significant difference between groups (P<0.05). Conclusion. Although there were RFA changes between groups, implant stability after experimental period shows alike tendency and good bone responses.

• The Journal of Advanced Prosthodontics
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• v.3 no.3
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• pp.136-139
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• 2011

PURPOSE. A new light curing urethane dimethacrylate and a cold curing resin with simpler and faster laboratory procedures may have even improved flexural properties. This study investigated the 3-point flexural strengths and flexural moduli of two alternate base materials. MATERIALS AND METHODS. A cold curing resin (Weropress) and a light curing urethane dimethacrylate base material (Eclipse). Along with Eclipse and Weropress, a high impact resin (Lucitone199) and three conventional base materials (QC 20, Meliodent and Paladent 20) were tested. A 3-point bending test was used to determine the flexural strengths and flexural moduli. The mean displacement, maximum load, flexural modulus and flexural strength values and standard deviations for each group were analyzed by means of one-way analysis of variance (ANOVA) (with mean difference significant at the 0.05 level). Post hoc analyses (Scheffe test) were carried out to determine the differences between the groups at a confidence level of 95%. RESULTS. Flexural strength, displacement and force maximum load values of Eclipse were significantly different from other base materials. Displacement values of QC 20 were significantly different from Lucitone 199 and Weropress. CONCLUSION. The flexural properties and simpler processing technique of Eclipse system presents an advantageous alternative to conventional base resins and Weropress offers another simple laboratory technique.

• The Korean Journal of Emergency Medical Services
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• v.3 no.1
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• pp.43-54
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• 1999

This study is attempted for the purpose of clearly understanding the stressors which emergency medical technology students experience during clinical practice, giving guidance in desirable direction and improvement of clinical practice, and giving the basic materials so that emergency medical technology students may practice effectively. The design of this study was a descriptive survey. The subjects in this study were 59 emergency medical technology students who were 2nd grade in D college. The collection of questionnaires took 3 days from September 1, 1999 to September 3, 1999. This researcher explained the purpose of this study to students, after they agreed to this survey, the researcher gave the questionnaire to them, had them answer the questions and collected the questionnaire immediately. Data analysis included percentage, mean and standard deviation, t-test and ANOVA trough SPSS computer program. The results of this study are, briefly, as follows; 1. In 'satisfaction-degree to specializing in the science of emergency medical technology' 27.1% of the subjects is revealed as 'satisfied' and in 'satisfaction-degree of clinical practice', 8.5% of the subjects is revealed as 'satisfied'. 2. Viewed from each of the categories of stressors which emergency medical technology students experience during clinical practice, 'ideals and values' is the category in which emergency medical technology students experience most severe stress at a mean 3.25 and 'personal relations' is the category in which emergency medical technology students experience mildest stress at a mean 2.82. The total stress degree mean is 3.06, which emergency medical technology students experience during clinical practice is revealed as 'moderate' stress. 3. Considering the stressor involved in each category, the results are as follows; (1) In 'environment', 'orientation to the hospital before clinical practice' is revealed as the most severe stressor at a menu 3.44. (2) In 'personal relations', 'relations with doctor and nurse' is revealed as the most severe stressor at a mean 3.59. (3) In 'role', 'unilaterally when their role is seems to be obscure' is revealed as the most severe stressor at a mean 4.10. (4) In 'ideals and values', 'difference between college practice and hospital practice' is revealed as the most severe stressor at a mean 3.88. (5) In 'activity', 'repetition of simple and functional work during clinical practice' is revealed as the most severe stressor at a mean 3.98. (6) In 'total stress factors', 'unilaterally when their role is seems to be obscure' is revealed as the most severe stress factor at a mean 4.10 and 'relations with comrade students' is revealed as the stress factor causing mildest stress at a mean 2.20. 4. Considering the relationship between the categories of stressors and the general characteristics, the results are as follows; (1) 'Environment' is revealed as being positively correlated with 'satisfaction degree of clinical practice'(F=3.53, p= .0359). (2) 'Ideals and values' is revealed as being correlated with 'sex'(t=-2.31, p= .0240) and 'satisfaction degree of clinical practice'(F=3.31, p= .0438).

• Korean Journal of Cleft Lip And Palate
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• v.6 no.2
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• pp.59-67
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• 2003

A cephalometric study was performed to reveal differences between skeletal Class III malocclusion patients and cleft lip and palate patients, The material for this study consisted of 16 males (mean age 19.8, range 17-29) and 9 females(mean age 19.4, range 16-27) with cleft lip and palate, and 222 Skeletal Class III malocclusion patients(males 106, females 116), Cephalometric tracing and measurements were done by one investigator. Results were followed: 1. Cleft lip and palate group had more retrusive maxilla than the skeletal Class III malocclusion group. 2, Cleft lip and palate group had smaller effective maxillary and mandibular length than skeletal Class III malocclusion group, and the difference was more prominent in the mandible than in the maxilla. 3. Dental compensation was not observed in the upper incisors of cleft lip and palate group and in the lower incisors it was smaller than skeletal Class III group. 4, In the Gonial angle and lower anterior facial height values, there was no significant difference between cleft lip and palate and skeletal Class III malocclusion group. These results can be used in orthodontic treatment planning and orthognathic surgery for the cleft lip and palate patients.

• Korean Journal of Applied Biomechanics
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• v.16 no.2
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• pp.37-44
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• 2006

The purposes of this study were to analyze and compare EMG activities of the pectoralis major, biceps brachii, triceps brachii, and brachioradialis muscles during biceps curls using a VRT device and an elastic tubing. Fifteen male college students were recruited as subjects and they performed 10-RM and 20-RM biceps curls. For each load and device condition, the mean and peak normalized EMG levels during different phases of a biceps curl were computed. For each load and phase, paired t-test (p.05) was used to find the significant difference between two devices. ANOVA with repeated measures was also used to find the significant difference among phases in terms of EMG values for each muscle. For each load and device condition, the peak and mean EMG levels during different phases of a biceps curl were computed The significant differences between devices were found in biceps brachii for EA, MD, LD phases, and triceps brachii muscles for all phases, respectively. However, no differences were found among phases for any muscle. This indicated that elastic band could have a similar characteristics of VRT. High antagonistic muscle activity as a function of injury prevention which found particularly in VRT device may suggest that elastic tubing can be a safer training device than VRT. This also imply that elastic tubing could be very effective as a home exercise tool for rehabilitation patients and elderly people.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06c
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• pp.107-110
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• 1994

In this paper, we describe the features of the fundamental frequency contour of Korean read speech, and propose a new stylization method to characterize the Fø pattern of segments. Our algorithm consists of three stylization processes : the segment level, the syllable level, and the sord level. For stylization of Fø contour in the segment level , we applied least square error minimization method to determine Fø values at initial, medial, and final position in a segment. In the syllable level, we determine the stylized Fø pattern of a syllable using the mean Fø value of each word and style information for each word, syllable and segment, we reconstruct Fø contour of sentences. The simulation results show that the error is less than 10% of the actual Fø contour for each sentence. In perception test, there is little difference between the synthesized speech with the original difference between the synthesized speech with the original Fø contour and the synthesized speech with the stylized Fø contour.

• Journal of Chest Surgery
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• v.17 no.2
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• pp.280-285
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• 1984

Although it is suspected that the foreign body sensation on the pharyngoesophageal region is caused by motility disturbance of upper esophageal sphincter, its pathophysiology is not yet clear. Esophageal manometry has become an important diagnostic tool in the evaluation of esophageal motor disorders such as dysfunction of upper esophageal sphincter. Intraluminal esophageal pressures were measured by perfusion manometry in fifteen patients with foreign body sensation on the pharyngoesophageal region and in twenty six controls. In upper esophageal sphincter, mean value of resting pressure of the patients by rapid pull-through technique was 45,9\ulcorner 15.6mmHg and 80.9\ulcorner9.7mmHg in the controls. The difference between the two groups was statistically significant. The distance from nostril to sphincter, length of sphincter, and resting pressure by station pull-through technique were not significantly different. The amplitude of esophageal peristalsis in the patients was reduced significantly at the level of the upper, mid and lower esophagus. The wave duration of the patients was reduced significantly at the level the upper and mid esophagus. The speed showed no difference between two groups. Length and resting pressure of lower esophageal sphincter revealed almost same values in two groups.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.4
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• pp.675-684
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• 1997

The bit rate control algorithm which is capable of handing scene change is proposed. In MPEG-2 TM5, block variance is used to measure block activity. But block variance is not consistent with human visual system and does not differenciate the distribution of pixel values within the block. In target bit allocation process of TM5, global complexity, obtained by results of previous coded pictures, is used. Since I pictures are spaced relatively far apart, their complexity estimate is not very accurate. In the proposed algorithm local variance is used to measure block activity and detect scene change. Local variance, using deviation from the mean of neighboring pixels, well represents the distribution of pixel values within the block. If scene change is detected, the local variance information is used for target bit allocation process. Allocating target bits for I picture, the average local variance difference between previous and current I picture is considered. The experimental results show that the proposed algorithm can detect scene change very precisely and gives better picture quality and higher PSNR values than MPEG-2 TM5.