• Title/Summary/Keyword: Difference-In-Difference

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Analysis of Door Height Difference and Door Flatness Difference of Built-in Side-by-Side Refrigerator Using Cabinet-Door Integrated Model (캐비닛-도어 통합모델을 이용한 빌트인 양문형 냉장고의 도어 상하단차와 앞뒤단차 해석)

  • Lee, Boo-Youn
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.5
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    • pp.76-83
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    • 2018
  • A cabinet-door integrated finite element model was constructed for a built-in side-by-side refrigerator with an ice dispenser, and its deformation was analyzed using the ANSYS finite element software. As loads, the food load needed to fill in the cabinet and doors and the thermal load occurring during normal operation conditions were taken into consideration. The door height difference (DHD) and door flatness difference (DFD) between the two doors of the freezing and refrigerating compartments were derived. The DHD and DFD under the assembled condition without applied loads satisfied the acceptance criteria specified by the refrigerator manufacturer. It appeared that the food load increases the DFD slightly. The thermal load tends to increase the differences because of the thermal deformation, especially the DFD, of the cabinet and doors.

Requirements and satisfaction with medical masks (보건용 마스크의 요구사항 및 만족도)

  • Younghee Park
    • The Research Journal of the Costume Culture
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    • v.31 no.1
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    • pp.1-17
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    • 2023
  • This study analyzed requirements for medical masks and difference in satisfaction based on demographic characteristics and side effects experience caused by wearing medical masks. Three factors related to requirements for medical masks were identified: wearing comfort and usability, blocking function for harmfulness, and design. As a result of the difference analysis for requirements of medical masks based on demographic characteristics, all three factors showed a significant difference in gender and occupation. Design did in age and monthly income. As a result of the presence or absence of breathing difficulties experience, design factor was significant. As a result of the presence or absence of skin trouble experience, wearing comfort and usability showed a significant difference. As a result of the difference in satisfaction with medical masks based on demographic characteristics and side effect experience caused by wearing medical masks, breathing, ear string tightness, blocking harmful substances, price, and over all wearing comfort showed a significant difference by gender, marital status, age, occupation, and monthly income, and the presence of absence of breathing difficulty experience and skin trouble experience, respectively. As a result of the interaction effect analysis between demographic characteristics and side effects experience caused by wearing medical masks, it showed a significant interaction effect between gender and monthly income, between marital status and monthly income, between monthly income and breathing difficulties experience, and between monthly income and skin trouble experience.

Temperature distribution analysis of steel box-girder based on long-term monitoring data

  • Wang, Hao;Zhu, Qingxin;Zou, Zhongqin;Xing, Chenxi;Feng, Dongming;Tao, Tianyou
    • Smart Structures and Systems
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    • v.25 no.5
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    • pp.593-604
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    • 2020
  • Temperature may have more significant influences on structural responses than operational loads or structural damage. Therefore, a comprehensive understanding of temperature distributions has great significance for proper design and maintenance of bridges. In this study, the temperature distribution of the steel box girder is systematically investigated based on the structural health monitoring system (SHMS) of the Sutong Cable-stayed Bridge. Specifically, the characteristics of the temperature and temperature difference between different measurement points are studied based on field temperature measurements. Accordingly, the probability density distributions of the temperature and temperature difference are calculated statistically, which are further described by the general formulas. The results indicate that: (1) the temperature and temperature difference exhibit distinct seasonal characteristics and strong periodicity, and the temperature and temperature difference among different measurement points are strongly correlated, respectively; (2) the probability density of the temperature difference distribution presents strong non-Gaussian characteristics; (3) the probability density function of temperature can be described by the weighted sum of four Normal distributions. Meanwhile, the temperature difference can be described by the weighted sum of Weibull distribution and Normal distribution.

Vertical Temperature Difference of Steel Box Girder Bridge Considering Asphalt Thickness of Concrete Deck (콘크리트 바닥판의 아스팔트 두께에 따른 강박스거더교의 상하 온도차)

  • Lee, Seong-Haeng
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.3
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    • pp.602-608
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    • 2019
  • The purpose of this study was to calculate the temperature difference of the sectional elevation according to the asphalt thickness of the steel box girder bridge deck and provide data on the design basis accordingly. Asphalt thicknesses produced four steel box girder model specimens of 0mm, 50mm, 100m and 150mm. In each model, 17 to 23 temperature sensors were attached to upper concrete and steel box girders. Six temperature gauges were selected to compare the temperature difference with Euro codes. The maximum and lowest temperature were calculated at the reference atmospheric temperature of each model, and the temperature difference (slope) was calculated based on this calculation. Four models of temperature difference are presented at each model. The 0mm to 100mm temperature difference models showed a -0.9 to -1.5 degree lower temperature difference compared to the temperature difference of Euro codes at the top of the slab. Overall, the measured temperature difference was found to be between 5.45% and 8.33% compared to the Euro code. The standard error coefficient, which was calculated by multiplying the average temperature with the standard error, was calculated from a range of 2.50 to 2.51 times the average at the top and bottom. It is estimated that the proposed temperature difference model can be used as a basic data when calculating temperature difference criteria for bridges in Korea.

The Accuracy of the Radiographic Method in Root Canal Length Measurement (근광장 측정에서 방사선 사진술의 정확도)

  • Jo Eun-Young;Park Chang-Seo
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
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    • v.28 no.2
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    • pp.471-489
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    • 1998
  • For the successful endodontic treatment, root canal should be cleaned thoroughly by accurate mechanical and chemical canal preparation and sealed completely with canal filling material without damaging the periapical tissues. The accuracy of the root canal length measurement is a prerequisite for the success of the endodontic treatment, and the root canal length is often determined by the standard periapical radiographs and digital tactile sense. In this study, the accuracy and the clinical usefulness of Digora/sup (R)/, an intraoral digital imaging processor and the conventional standard radiographs were compared by measuring the length from the top of the file to the root apex. 30 single rooted premolars were invested in a uniformly sized blocks and No.25 K-file was inserted into and fixed in each canal. Each block was placed in equal distance and position to satisfy the principle of the bisecting angle and paralleling techniques and Digora/sup (R)/ system's image and standard periapical radiographs were taken. Each radiograph was examined by 3 different observers by measuring the length from top of the file to the root apex and each data was compared and analyzed. The results were as follows; 1. In the bisecting angle technique, the average difference between the Digora/sup (R)/ system and standard periapical radiograph was 0.002 mm and the standard deviation was 0.341 mm which showed no statistically significant difference between the two systems(p>0.05). Also, in the paralleling technique, the average difference between these two system was 0.007 mm and the standard deviation was 0.323 mm which showed no statistically significant difference between the two systems(p>0.05). 2. In Digora/sup (R)/ system, the average difference between the bisecting angle and paralleling technique was -0.336 mm and the standard deviation was 0.472 mm which showed a statistically significant difference between the two techniques(p<0.05). Also, in the standard periapical radiographs, the average difference between the bisecting angle and paralleling technique was 0.328 mm and the standard deviation was 0.517 mm which showed a statistically significant difference between these two techniques(p<0.05). 3. In Digora/sup (R)/ system and the standard periapical radiographs. there was a statistically significant difference between the measurement using the bisecting angle technique and the actual length(p<0.05), But there was no statistically significant difference between the measurement using the paralleling technique and the actuallength(p>0.05). In conclusion. the determination of the root canal length by using the Digora/sup (R)/ system can give us as good an image as the standard periapical radiograph and using the paralleling technique instead of the bisecting angle technique can give a measurement closer to the actual canal length. thereby contributing to a successful result. Also. considering the advantages of the digital imaging processor such as decreasing the amount of exposure to the patient. immediate use of the image. magnification of image size. control of the contrast and brightness and the ability of storing the image can give us good reason to replace the standard periapical radiographs.

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Validity of a Portable APDM Inertial Sensor System for Stride Time and Stride Length during Treadmill Walking

  • Tack, Gye Rae;Choi, Jin Seung
    • Korean Journal of Applied Biomechanics
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    • v.27 no.1
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    • pp.53-58
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    • 2017
  • Objective: The purpose of this study was to compare the accuracy of stride time and stride length provided by a commercial APDM inertial sensor system (APDM) with the results of three dimensional motion capture system (3D motion) during treadmill walking. Method: Five healthy men participated in this experiment. All subjects walked on the treadmill for 3 minutes at their preferred walking speed. The 3D motion and the APDM were simultaneously used for extracting gait variables such as stride time and stride length. Mean difference and root mean squared (RMS) difference were used to compare the measured gait variables from the two measurement devices. The regression equation derived from the range of motion of the lower limb was also applied to correct the error of stride length. Results: The stride time extracted from the APDM was almost the same as that from the 3D motion (the mean difference and RMS difference were less than 0.0001 sec and 0.0085 sec, respectively). For stride length, mean difference and RMS difference were less than 0.1141 m and 0.1254 m, respectively. However, after correction of the stride length error using the derived regression equation, the mean difference and the RMS difference decreased to 0.0134 m and 0.0556 m or less, respectively. Conclusion: In this study, we confirmed the possibility of using the temporal variables provided from the APDM during treadmill walking. By applying the regression equation derived only from the range of motion provided by the APDM, the error of the spatial variable could be reduced. Although further studies are needed with additional subjects and various walking speeds, these results may provide the basic data necessary for using APDM in treadmill walking.

Clinical Study on the Sasang Constitutional Pulse Using Array Piezoresistive Sensor (어레이 압저항 센서를 활용한 체질맥 임상연구)

  • Lee, Si-Woo;Joo, Jong-Cheon;Kim, Kyung-Yo;Kim, Jong-Yeol
    • Journal of Sasang Constitutional Medicine
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    • v.18 no.1
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    • pp.118-131
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    • 2006
  • 1. Objective Pulse diagnosis is generally applied to Traditional Oriental Medicine but not to Sasang Constitution diagnosis. Recently new pulse analyzer using array piezoresistive sensor and multi-channel robot arm developed. It reflects Oriental Medical Doctors' diagnostic processes, and its reproducibility test was done at Korea Institute of Oriental Medicine. We performed this study to set parameters diagnosing Sasang Constitution. 2. Methods One hundred thirty three subjects participated in this study. They are healty and approved this study. Before being tested with pulse analyzer, they had interview with Sasang Constitution Specialist to diagnose their Sasang Constitution. We established some useful parameters from parameters of pulse analyzer according to the Original Texts of Oriental Medicine and clinical experiences to analyze with clinical data of this study. 3. Results (I) There is a significant difference in pre-dicrotic notch time among all parameters of pulse analyzer in Sasang Constitution groups(P=0.047). (2) There is a significant difference in maximum pulse pressure in 33 to 48 year Sasang Constitution groups(P=0.010). (3) There is a significant difference in frequency width in 17 to 32 year Sasang Constitution groups(P=0.002). (4) There is a significant difference in CFS value in groups which OMD diagnoses; Floating & Sinking pulse(P=0.020). (5) There is a significant difference in pulse rate in groups which OMD diagnoses; Rapid & Slow pulse(P=0.000). (6) There is a significant difference in maximum pulse pressure in groups which OMD diagnoses; Deficient & Solid pulse(P=0.000). 4. Conclusions Analyzing parameters in each Sasang Constitution group, we found it shows significant difference in maximum pulse pressure and corresponding tendency in coefficient of floating & sinking pulse with theories of Sasang Consti-tutional Medicine. As we accumulate more clinical data, we will establish algorithm to diagnose Sasang Constitution using a pulse analyzer.

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Effects of White Noises on Gait Ability of Hemiplegic Patients during Circuit Balance Training

  • Jang, Na-Young;Kim, Gi-Do;Kim, Bo-Kyoung;Kim, Eun-Hee;Koo, Ja-Pung;Shin, Hee-Joon;Choi, Seok-Joo;Choi, Wan-Suk
    • Journal of International Academy of Physical Therapy Research
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    • v.3 no.1
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    • pp.370-377
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    • 2012
  • This study examines the effects of different environments on the application of hemiplegia patients circuit balance training. Group 1 performed circuit balance training without any auditory intervention Group 2 performed training in noiseless environments and Group 3 performed training in white noise environments. First, among lower extremity muscular strength evaluation items, maximum activity time(MAT) was not significantly different(p>.05). Maximum muscle strength(MMS) increased significantly in Group 3(p<.01), there was no significant difference in MMS among the groups. Average muscle strength(AMS) indexes also significantly increased in Group 3(p<.01), there was no significant difference in AMS among the groups. Second, among balancing ability evaluation items, Berg's balance scale(BBS) scores significantly increased in all groups(p<.05), BBS scores were significantly difference among the groups. Based on the results, Group 1, 2 and Group 1, 3 showed significant increases (p<.05). Functional reach test(FRT) values significantly increased in Group 2, 3(p<.05), and there was no significant difference in FRT values among the groups. Timed up and go(TUG) test values significantly decreased in Group 2, 3(p<.05), and there was no significant difference in TUG test values among the groups. Third, among walking speed evaluation items, the time required to walk 10m significantly decreased in all groups(p<.05), and there was no significant difference in the values among the groups. Average walking speeds showed significant increases in Group 1, 3(p<.05), and there was no significant difference in the values among the groups. Based on the results of this study, noise environments should be improved by either considering auditory interventions and noiseless environments, or by ensuring that white noise environments facilitate the enhancement of balancing ability.

A study on the periodontal status of second molar adjacent third molar (제 3대구치와 인접한 제 2대구치의 치주상태에 대한 고찰)

  • Lee, Hae-Doo;Hong, Ki-Seok;Chung, Chin-Hyung;Lim, Sung-Bin
    • Journal of Periodontal and Implant Science
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    • v.36 no.2
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    • pp.489-502
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    • 2006
  • The purpose of this study was to determine the relationship between the third molar and periodontal status of the adjacent second molar. Fifty patients who had four maxillary and mandibular second molars were consecutively selected for the study subjects. The subjects provided a total of 200 molars, i. e., 100 maxillary and 100 mandibular molars, and classified the groups as follows; third molars that are normally erupted are control group, that are impacted are test 1 group, that are simply extracted are test 2 group, that are surgically extracted are test 3 group. Probing depth, plaque index, gingival index and mobility were measured. The results were as follows. 1. In mesial probing depth, there was no significantly difference. In distal probing depth, there was a significantly difference between control group and test 1 & 3 group in maxilla and between control & test 2 group and test 1& 3 group in mandible(p<0.05). 2. In buccal probing depth, there was a significantly difference between test 2 group and test 3 group in mandible. In lingual probing depth, there was a significantly difference between control group and test 1 & 3 group in mandible(p<0.05). 3. In plaque index, there was a significantly difference between test 1 group and test 2 group in maxilla, between test 1 group and control & test 2 group in mandible(p<0.05). 4. In gingival index, there was a significantly difference between control group and test 1 & 3 group in mandible. In mobility, there was no significantly difference(p<0.05). As a result of this study, the second molars adjacent to the third molars that are impacted or surgically extracted had poor prognosis, so impacted third molars should be extracted in early time and the second molars are actively treated for periodontal health.

Physiological Index of the Elderly with Diabetes According to Dance Based Low Intensity Combined Kinesitherapy (무용기반 저강도 복합운동요법이 당뇨노인의 생리적 지표에 미치는 효과)

  • Kim, Su-Jin
    • The Journal of the Korea Contents Association
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    • v.18 no.5
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    • pp.683-694
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    • 2018
  • The purpose of this study was to investigate the effect of low intensity combined kinesitherapy on type 2 diabetes mellitus and to compare the effects of exercise and methodology aspects, the difference in the post - test scores between fasting glucose and blood lipids in the control group (exercise group) and the control group (exercise group) that prescribed the dance - exercise and low intensity combined exercise for the elderly diabetic patients for 12 weeks sample t-test. the main results of the study are summarized as follows. first, fasting blood sugar showed difference in pre - post - difference of group compared to control group. second, the total cholesterol was found to have a statistically significant difference in the experimental group from pre - post - difference. third, the neutral region showed no statistically significant differences in both experimental and comparator groupsfrom pre - post - difference. fourth, high-density lipoprotein cholesterol levels showed no statistically significant difference in both experimental and comparator groups from pre - post - difference. fifth, low density lipoprotein cholesterol showed statistically significant difference in the experimental group from pre - post - difference group. in conclusion, this study is significant in that the combined effects of dance - motion activities and low intensity combined exercise for elderly with type 2 diabetes were quantitatively proved by using physiological index who had not been treated previously.