• Journal of the Korean Society of Radiology
• /
• v.13 no.2
• /
• pp.153-158
• /
• 2019

The purpose of this study is to compare and analyse the differences between a customized small finger made by 3D printing technology, a real small finger, and the other made from plaster of an orthotic company. The areas and the volumes of each cross-section were measured by Computer tomography(CT) and a 3D scanner and analysis of variance was performed to find out the differences of each shape. The areas of the point of 15.69mm, Distal Interphalangel Joints, were measured 30 times respectively using the caliper toll function of Picture Archiving Communication System(PASC) program. The volumes were measured by Configure Units of Meshmixer Program. There was no significant difference in the areas between three of them and there was 0.2 mm gap in the volume, which was more than the significance probability. Therefore, the result of this study shows the availability of finger orthoses made by 3D printing technology in the medical field.

• KDI Journal of Economic Policy
• /
• v.12 no.4
• /
• pp.21-46
• /
• 1990

This paper, a sequel to Yoo and Lee (1990), attempts to investigate the interindustry determinants of technical efficiency in Korea's manufacturing industries, and also to conduct an exploratory analysis on the stability of technical efficiency over time. The hypotheses set forth in this paper are most found in the existing literature on technical efficiency. They are, however, revised and shed a new light upon, whenever possible, to accommodate any Korea-specific conditions. The set of regressors used in the cross-sectional analysis are chosen and the hypotheses are posed in such a way that our result can be made comparable to those of similar studies conducted for the U.S. and Japan by Caves and Barton (1990) and Uekusa and Torii (1987), respectively. It is interesting to observe a certain degree of similarity as well as differentiation between the cross-section evidence on Korea's manufacturing industries and that on the U.S. and Japanese industries. As for the similarities, we can find positive and significant effects on technical efficiency of relative size of production and the extent of specialization in production, and negative and significant effect of the variations in capital-labor ratio within industries. The curvature influence of concentration ratio on technical efficiency is also confirmed in the Korean case. There are differences, too. We cannot find any significant effects of capital vintage, R&D and foreign competition on technical efficiency, all of which were shown to be robust determinants of technical efficiency in the U.S. case. We note, however, that the variables measuring capital vintage effect, R&D and the degree of foreign competition in Korean markets are suspected to suffer from serious measurement errors incurred in data collection and/or conversion of industrial classification system into the KSIC (Korea Standard Industrial Classification) system. Thus, we are reluctant to accept the findings on the effects of these variables as definitive conclusions on Korea's industrial organization. Another finding that interests us is that the cross-industry evidence becomes consistently strong when we use the efficiency estimates based on gross output instead of value added, which provides us with an ex post empirical criterion to choose an output measure between the two in estimating the production frontier. We also conduct exploratory analyses on the stability of the estimates of technical efficiency in Korea's manufacturing industries. Though the method of testing stability employed in this paper is never a complete one, we cannot find strong evidence that our efficiency estimates are stable over time. The outcome is both surprising and disappointing. We can also show that the instability of technical efficiency over time is partly explained by the way we constructed our measures of technical efficiency. To the extent that our efficiency estimates depend on the shape of the empirical distribution of plants in the input-output space, any movements of the production frontier over time are not reflected in the estimates, and possibilities exist of associating a higher level of technical efficiency with a downward movement of the production frontier over time, and so on. Thus, we find that efficiency measures that take into account not only the distributional changes, but also the shifts of the production frontier over time, increase the extent of stability, and are more appropriate for use in a dynamic context. The remaining portion of the instability of technical efficiency over time is not explained satisfactorily in this paper, and future research should address this question.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.11
• /
• pp.5254-5260
• /
• 2012

The purpose of this study is to find the relationship between lumber Herniated Nuclesus Pulposus of specific part and fat infiltration in paraspinal muscle. Also we intended to find the relationship between Body Mass Index(BMI) and fat infiltration ratio in the lumber paraspinal muscle based on the sexes of patients. We conducted this study of patients who visited our hospital from May, 2010 to May, 2012. The subjects are composed of 40 patients(20 females and 20 males), who are 30 to 50 years old suffering from severe lumber herniated nuclesus pulposus, who had or were going to have operation treatment. BMI is measured through anthropometry of each patient and fat infiltration inside the muscle is estimated by measuring the cross section area of lumbar paraspinal muscle from mid-cross section of disc(L2-S1) and fat infiltration ratio. The data of this study are analyzed by independent t-test to figure out the difference of fat infiltration between male and female, and by paired sample T-test after getting mean and standard deviation to find the changes of fat infiltration of lumbar on each level. Also correlation analysis is done by setting age as a control variable to find the correlation between BMI and fat infiltration of the whole lumbar. As a result, we could get only the meaningful difference between the sexes on upper lumber part(L2-L3) while we couldn't find any significant difference in the rest of lumbar(L3-S1). Besides, the changes of fat infiltration ratio on each lumbar level increased rapidly from lumbar 3,4 to lumbar 4,5. We also found that there is no correlation between fat infiltration ratio of lumbar paraspinal muscle(L2-S1) and BMI.

• Journal of Korea Technology Innovation Society
• /
• v.10 no.3
• /
• pp.509-530
• /
• 2007

This paper examined the relationship between innovation and firm performance by integrating industry competitive context and firm-level knowledge constructs. After controlling for firm site, age, and the presence of a union, cross-section analysis of survey data from 1,419 medium sized manufacturing firms yielded following findings. The first was the expected positive relationship between firm-level innovation and firm knowledge and also industry dynamism, as measured by the intensity of industry-level R&D. This results indicate that industries with greater aggregate levels of R&D intensity are home to higher rates of firm-level innovative activity and managers must increase their numbers of technical staff and the level of training. But the interaction between firm knowledge and industry dynamism was non-significant. Second, innovation was not significantly related to firm performance, as measured by revenue growth. This relationship was not moderated by industry dynamism and firm level knowledge. In high and low technology sectors, the relationship between innovation and performance was non-significant, consistent with the full-sample analysis. The results suggest that the effects of firm-level knowledge assets and investments in training don't work in different ways in different industry settings. This research used three control variables to analyze innovation and firm performance. Firm age was negatively associated with firm performance and did not significantly predict innovation. Firm size was positively associated with innovation and performance in the low-technology sector. The presence of a labor union was not a significant with respect to innovation.

• Health Policy and Management
• /
• v.16 no.4
• /
• pp.48-67
• /
• 2006

The aim of the study was to examine levels of satisfaction with health care in North Korea and to identify factors associated with it using a convenience sample of North Korean refugees in China. Data from the 2004 Survey of Health Seeking Behavior of North Korean Households conducted by the Center for Refugee and Disaster Response, Johns Hopkins Bloomberg School of Public Health were used. The study subjects were 273 North Korean refugees whose length of stay in China was less than 3 months. Factor analysis was used to extract factor dimensions from the 12 satisfaction items. Bivariate (t test and ANOVA) and multiple regression analyses were used in examining factors associated with satisfaction with health care use in North Korea Overall, satisfaction level was low ($2.36{\pm}0.36$, score range: 1-5). Of the three-factor dimensions, physician skills scored the highest $(2.93{\pm}0.36)$, followed by drug availability $(2.51{\pm}0.07)$ and general cleanliness $(1.66{\pm}0.55)$. In the multiple regression analysis, having a usual source of care was significantly associated with patient satisfaction. Respondents who identified primary care (section) doctors as their usual source of care tended to be less satisfied than those with the city or county hospital as their usual source of care. County residents tended to report a lower degree of satisfaction with general cleanliness than city residents. Among socioeconomic characteristics, the number of household assets positively predicted satisfaction with drug availability. North Korean residents appear to be dissatisfied with their medical care. It may reflect some inadequacies in the North's universal health care system to meet the healthcare needs of its people.

• Journal of Sericultural and Entomological Science
• /
• v.14 no.2
• /
• pp.95-103
• /
• 1972

The major purpose of this study is to collect the information related on the aspects of economic efficiency for solving the problems which are faced by farmers and areas, and providing scientific facts to farmers and related institutions for further development of sericultural sector in Korea. In order for obtaining the related information 12 sample areas among 23 major sericultural farming areas and 30 farm units in each area are selected and analyzed in this study. The fold suevey is made by member of this study team and graduate students in the Department of Sericultural Science with a prepared questionnaires. Cross-section and regression analysis methods are employed for processing the data in this study. The major findings obtained are as followings. 1. Sericultural earnings per Tanbo is, on the average, 22, 752 won in new cultivated areas and 29, 403 won in ordinary ones. There are big difference in the size of earnings by areas, especially, 46, 968 won in Kumo mountain area, compared with 16, 798 won in Yeoju and Yichun areas. General trend is finded that small scale farming units are made higher earnings and operating their farms efficiently. 2. Cocoon production expences per Tanbo is 16, 737 won in new cultivated areas and 19, 802 won in ordinary areas. There are also big difference in farming expences, especially, 27, 389 won in Sudang area, compared with 11, 689 won in Emjin area. 3. Sericultural income per Tanto is 10, 664 won in ordinary areas and 6, 898 won in new cultivated areas. Farmers in Kumo mountain area make the highest income of 21, 164 won and lowest income of 1, 296 won in Sudang area. It can be generized that about 30-50 a sized farmers make higher income. 4. Land, labor and capital productivities estimated by fitting Cobb-Douglas functions in ordinary areas are higher than in new cultivated areas, especially, labor productivity is higher in ordinary areas. 5. Changsung, Kwangna, Yunsun and Kumo mountain areas are technically and economically efficient. Sudang and Mujinchang areas are technically successful but economically inefficient and Emjin and Honam areas are technically inefficient but economically efficient. YeojuYichun, Chunwon and West Kyongnam are technically and economically inefficient. Technical and economic improvement program should be implemented for these areas. 6. Estimated Internal Rate of Return (IRR) on capital investment in Chongwon are is 23.5 percent. It is economically feasible, if we consider 20 percent of opportunity cost of capital in our economy.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.24 no.6
• /
• pp.483-494
• /
• 2022

Owing to the saturation of ground spaces in downtown areas, underground spaces are being developed increasingly. Underground spaces are utilized for transportation, water supply and sewerage, communication zones, electric power zones, and various cultural complexes. In Korea, for excavating underground spaces, blasting methods using gunpowder such as the New Austrian Tunneling Method (NATM) are mainly used. However, the blasting method causes vibration and noise during tunnel excavation, generating many complaints from residents in the vicinity of the excavation site. To address this problem, various methods have been developed, and recently, vibration and noise have been reduced using deep excavation. This study predicts blast vibration changes according to the depth, under the same blasting and tunnel conditions, using numerical analysis based on the blast vibration measurement data of the GTX-A route, the tunnel cross-section drawings, and ground investigation reports. Furthermore, the necessary separation distance from densely populated areas such as residential areas is suggested by analyzing the trend of decreasing blast vibration according to the distance from ground surface directly above the blasting location.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.24 no.6
• /
• pp.659-677
• /
• 2022

Hydrogen is emerging as a next-generation energy source and development and supply of FCEV (hydrogen fuel cell electric vehicle) is expected to occur rapidly. Accordingly, measures to respond to hydrogen car accidents are required and researches on the safety of hydrogen cars are being actively conducted. In this study, In this study, we developed a hydrogen car accident scenarios suitable for domestic conditions for the safety evaluation of hydrogen car in road tunnels through analysis of existing experiments and research data and analyzed and presented the hazard distance according to the accident results of the hydrogen car accident scenarios. The accident results according to the hydrogen car accident scenario were classified into minor accidents, general fires, jet flames and explosions. The probability of occurrence of each accident results are predicted to be 93.06%, 1.83%, 2.25%, and 2.31%. In the case of applying the hydrogen tank specifications of FCEV developed in Korea, the hazard distance for explosion pressure (based on 16.5 kPa) is about 17.6 m, about 6 m for jet fire, up to 35 m for fireball in road tunnel with a standard cross section (72 m²).

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.26 no.2
• /
• pp.113-128
• /
• 2024

Items of road tunnel PISD (Precise Inspection for Safety and Diagnosis) were reviewed and analyzed using newly enhanced MMS (Mobile Mapping System) technology. Possible items with MMS can be visual inspection, survey and non-destructive test, structural analysis, and maintenance plan. The resolution of 3D point cloud decreased when the vehicle speed of MMS is too fast while the calibration error increased when it is too slow. The speed measurement of 50 km/h is determined to be effective in this study. Although image resolution by MMS has a limit to evaluating the width of crack with high precision, it can be used as data to identify the status of facilities in the tunnel and determine whether they meet disaster prevention management code of tunnel. 3D point cloud with MMS can be applicable for matching of cross-section and also possible for the variation of longitudinal survey, which can intuitively check vehicle clearance throughout the road tunnel. Compared with the measurement of current PISD, number of test and location of survey is randomly sampled, the continuous measurement with MMS for environment condition can be effective and meaningful for precise estimation in various analysis.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.24 no.4
• /
• pp.325-335
• /
• 2008

The junction between resilient denture liner and the denture base is difficult to finish and polish due to difference of the physical property of the materials. Gaps tend to be formed during finishing and polishing procedures. The purpose of this study was measuring the width of junctional gap between $Molloplast-B^{(R)}$ and denture base material after finishing and polishing procedure, and evaluating the effect of method and direction on gap width. $Molloplast-B^{(R)}$ was processed (according to the manufacturer's instruction) against Lucitone $199^{(R)}$ acrylic resin. 50 specimens were fabricated with a raised center section. All of specimens were examined and photographed with a stereoscopic microscope(x120), and the largest gap along the junction of $Molloplast-B^{(R)}$ and acrylic resin on each specimen was measured. One-way analysis of variance(ANOVA) and independent t-test at 95% confidence level were used to analyze the data and to compare groups. The results of this study were as follows. In comparison with finishing tools, the gap width was the largest in $Molloplast^{(R)}$-Cutter and the smallest in FSQ-cross cut bur. There was statistically significant difference between FSQ-cross cut bur and $Molloplast^{(R)}$-Cutter(p<0.05). There was no significant difference in gap width between the direction of polishing. The mean value of gap width was the smallest in case of no polishing, and the largest in case of polishing with pumice & tin oxide. There was statistically significant difference between pumice and pumice & tin oxide. From the results, it is concluded that the use of $Molloplast^{(R)}$-Cutter in clinic need serious consideration even though it has good cutting ability. Further careful study is needed for finishing and polishing methods for decreasing gap width in junction of two materials.