• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.611-619
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• 2017

Objective : In addition to bone bridging inside a cage or graft (intragraft bone bridging, InGBB), extragraft bone bridging (ExGBB) is commonly observed after anterior cervical discectomy and fusion (ACDF) with a stand-alone cage. However, solid bony fusion without the formation of ExGBB might be a desirable condition. We hypothesized that an insufficient contact area for InGBB might be a causative factor for ExGBB. The objective was to determine the minimal area of InGBB by finite element analysis. Methods : A validated 3-dimensional, nonlinear ligamentous cervical segment (C3-7) finite element model was used. This study simulated a single-level ACDF at C5-6 with a cylindroid interbody graft. The variables were the properties of the incorporated interbody graft (cancellous bone [Young's modulus of 100 or 300 MPa] to cortical bone [10000 MPa]) and the contact area between the vertebra and interbody graft (Graft-area, from 10 to $200mm^2$). Interspinous motion between the flexion and extension models of less than 2 mm was considered solid fusion. Results : The minimal Graft-areas for solid fusion were $190mm^2$, $140mm^2$, and $100mm^2$ with graft properties of 100, 300, and 10000 MPa, respectively. The minimal Graft-areas were generally unobtainable with only the formation of InGBB after the use of a commercial stand-alone cage. Conclusion : ExGBB may be formed to compensate for insufficient InGBB. Although various factors may be involved, solid fusion with less formation of ExGBB may be achieved with refinements in biomaterials, such as the use of osteoinductive cage materials; changes in cage design, such as increasing the area of polyetheretherketone or the inside cage area for bone grafts; or surgical techniques, such as the use of plate/screw systems.

• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.691-700
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• 2017

Objective : The authors prospectively analyzed the effect of one-level or two-level anterior cervical discectomy and fusion (ACDF), comparing stand-alone cages and cage-with-plate fixation constructs with respect to clinical outcomes and radiologic changes. Methods : A total of 84 patients who underwent one-level (n=52) or two-level ACDF (n=32) for cervical disc disease and who completed 2 years of follow-up were included in this study. The patients were divided by cervical level and grouped into ACDF-Cage-only and ACDF-Cage-with-plate groups. The following parameters were assessed using radiographs : subsidence, C2-C7 lordosis angle, fusion segment angle, adjacent disc space narrowing, and fusion status. Clinical outcomes were assessed using the neck disability index (NDI) and visual analog scale scores for arm pain. Results : In the comparison of one-level ACDF-cage-only and ACDF-cage-with-plate groups, the NDI score was better in the cage-only group at the 3-, 12-, and 24-month follow-ups : however, no significant difference in clinical outcomes was observed. In the comparison of two-level ACDF-cage-only and ACDF-cage-with-plate groups, no difference in any clinical outcome was observed between the two groups. At the 24-month follow-up, subsidence was observed in 45.8% of patients in the one-level cage-only group and 32.1% of patients in the one-level cage-with-plate fixation group. There was no statistically significant difference in the incidence rate between the two groups (p=0.312). Subsidence in the two-level cage-only group (66.6%) was significantly more frequent than in the two-level cage-with-plate fixation group (30%; p=0.049). The fusion rate for patients in the one-level cage-only group was not significantly different from that in the one-level cage-with-plate fixation group (cage-only, 87.5%; cage-with-plate fixation, 92.9%; p=0.425) ; fusion rate in the two-level patients were also similar between groups (cage-only, 83.3%; cage-with-plate fixation, 95%; p=0.31). Conclusion : Our clinical results showed that for single-level cases, plate fixation had no additional benefit versus cage-only; for two-level ACDF cases, the fusion rate and clinical outcomes were similar, although the cage-with-plate fixation group had a lower incidence of cage subsidence than did the cage-only group. We conclude that physicians should be aware of this possible disadvantage associated with using cervical plates in one-level ACDF. However, in two-level ACDF, subsidence is more likely to occur without plate fixation, and thus the addition of plate fixation should be considered.

• Journal of Korean Medicine Rehabilitation
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• v.24 no.4
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• pp.129-136
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• 2014

Objectives The purpose of this study is to find out clinical and radiological correlation between lumbar lordotic angle, lumbar intervertebral disc angle and lumbar spinal stenosis. Methods Total 250 patients' who had visited Bu-Chun Jaseng Hospital of Korean Medicine lumbar lordotic angle, intervertebral disc angle of L4/5 and dural sac dimension of L4/5 were measured by X-ray and MRI films. We analysed correlation between lumbar lordotic angle, intervertebral disc angle of L4/5 and lumbar spinal stenosis in terms of clinical and radiological aspect. Results 1. The mean intervertebral disc angle of L4/5 were $10.72{\pm}3.98^{\circ}$, the mean lumbar lordotic angle were $41.97{\pm}11.73^{\circ}$ and the mean dural sac dimension of L4/5 were $133.18{\pm}45.46mm^2$. 2. This study shows that dural sac dimension of L4/5 was inversely reated to intervertebral disc angle of L4/5 by statistically (p<0.05). 3. There was visible difference regarding intervertebral disc angle of L4/5 between patients who had been diagnosed with lumbar spinal stenosis by clinically and patients who had not been diagnosed with lumbar spinal stenosis by clinically; The former's angle was relatively higher than the latter's (p<0.05). Conclusions There was a statistical significance between intervertebral disc angle of L4/5 and lumbar spinal stenosis in single-segment.

• Journal of Korean Academy of Nursing
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• v.16 no.3
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• pp.108-122
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• 1986

Changing concepts of health care, are stimulating the demand for health care, thereby orienting society to health care rights to such an extent that they are deemed as fundamental ones inalienable to man. Concomitantly, qualitative as well as quantative improvement is being sought in the nursing service field. Today, efforts are being made in various areas, especially to qualitatively improve nursing services. A second issue concerns proper staffing. It is important to study staffing, in as much as it continues to be the most persistent and critical problem facing hospital nursing administrators today. It involves quantity, quality, and utilization of nursing personnel. A great deal of attention has been focused on this problem since mid 1930's when nursing services began to be felt as an important segment of hospital operation representing the largest single item of hospital budgets. Traditionally, the determination and allocation of nursing personnel resources has relied heavily on gloval approaches which make use of fixed staff-to-patient ratios. It has long been recognized that these ratios are insensitive to variations between institutions and among individual patients. Therefore, the aim of this thesis is to point to the urgent need for the development of methodology and criteria suited to the reality of Korea. The present research selected one place, the W Christian Hospital, and was conducted over a period 10 days from January, and nurses who were them on duty in their unit. The total num-her of patients surveyed was 1,426 and that of 354. The research represents many variables affecting the direct patient care time using the result from the direct observation method, then using a calculation method to estimate the relationship between the patients care time and selected variables in the hospital setting. The amount of direct patient care time varies with many factors, such 89 the patients age. diagnosis and time in hospital. Differences are also found from hospital, clinic to clinic, ward to ward, and even shift to shift. In this research, the calculation method of estimating the required member of nursing staff is obtained by dividing the time of productive patient care activity(with the time of patient care observed), by the sum of the productive time that each the staff can supply, i.e., 360 minutes, which is obtained by deducting the time for personal activities. The results indicate a substantial difference between the time of productive patient care observed directing and the time of the productive patient care estimated using calculating method. If we know accurately the time of the direct patient care on a shift, there required number of staff members calculated if the proper method can be determinded should be able the time of the direct patient care be estimated by the patient classification system, but this research has shown this system to be in accurate in Korea. There are differences in the recommended time of productive patient care and the required number of nursing staff depending upon which method is used. The calculated result is not very accurate, so more research is needed on the patient classification system.

• Journal of Distribution Science
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• v.11 no.4
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• pp.61-72
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• 2013

Purpose - It is widely accepted that the process of developing marketing strategy is composed of three steps: market segmentation, target market selection and positioning. However, mass marketing strategy based on cost reduction through economies of scale and standardized products, can be also an effective strategic option. Many marketing scholars including Theodore Levitt emphasize the importance of applying the mass production concept to various industries including service industries. Especially, in times of economic downturn, the capability of providing consumers with low-priced, value products can be an important source of competitive advantage, as well as the ability of providing high-priced premium products. Marketers should decide whether they will implement mass marketing strategy or target marketing strategy. The present study theoretically shows that firms should understand the target customers' price elasticity as well as the firm's cost structure in order to make such a strategic decision. Research design, data, and methodology - Instead of implementing an empirical study, this study provides a theoretical(mathematical) investigation on the effect of consumers' price elasticity on a firm's optimal price level, profit, sales volume, revenue, and cost. The results are mostly deduced from derivative calculations and several graphs are utilized to represent the results on the relationships between the variables under study. Results - The analytical results suggest that it is more profitable for a firm to adopt the segment/target marketing strategy (more specifically the differentiation strategy) when the degree of consumers' heterogeneity is high and the proportion of the fixed cost in the total cost is low. On the other hand, if the degree of consumers' heterogeneity is low and the fixed cost is high, it is better to adopt the mass marketing strategy or the cost leadership strategy. The strategy of concentrating on a single target market will be effective when consumers' needs are highly heterogeneous but the fixed cost is high. Any of the three types of generic strategies proposed my Porter(1980, 1985) can be applied when both the consumers' heterogeneity and the fixed cost are low. This study also proposes the contribution-margin-based method for developing the optimal pricing strategy. Conclusions - One of the primary roles of marketers is to find a proper compromise between the two conflicting goals of maximizing customer satisfaction and minimizing cost. In order to do so, he or she should understand the characteristics of the target customers as well as the cost structure of the firm. In addition to the theoretical analyses, this study discusses several business cases and explains how superior companies find the optimal compromise position between these two goals and dominate the market. One of the radical changes recently taking place in business arena is the reduction of production and distribution costs of both physical goods and information due to the advancement and the wide diffusion of information technology. The cost reduction combined with lowered priced elasticity incurred by customized products and services, will enable many firms to adopt the mass customization strategy.

• Journal of Korean society of Dental Hygiene
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• v.9 no.3
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• pp.456-467
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• 2009

For this study, self-completion survey for 149 implant patients of dental clinics and hospitals in Seoul and Kyunggi areahas been executed in order to provide basic data for increasing patient satisfaction level by effective consultation and various information for the patients who want dental implantation. The conclusion of the study is like below. 1. In terms of demographics of the study, sample size of female patients(n=85) was more than that of male patients(n=64) and patients in their 50s were major age group. When it comes to the educational level, university graduates were 85 and high school graduates were 44. And 132 were married and 6 were single. In the income level, monthly income between KRW 2~4 million was major group(n=59). 2. In the study, patients' most concern was complication or adverse events(n=41), and price(n=39) & annual dental check-up(n=49) were following it. And 80 patients responded that dental health is the most valuable(n=80) and whole body health was following(n=37). In terms of knowledge on dental implant, 100 patients responded 'know just a little', 31 and 13 answered 'generally know' and 'well know' each. 3. As a result of analyzing implant patients' satisfaction level by segment, general satisfaction rate was highest as 4.20, social satisfaction rate was 4.20, psychological function was 4.06 and masticatory function was 3.90. 4. Based on the result of comparing patient satisfaction level by general characters of dental implant patient, chewing function was the highest in the age group of 60s with score of 4.21 and in terms of social function, the group with over KRW 8 million of monthly income showed highest score with 4.54. When it comes to the psychological function, patients in their 70s showed highest satisfaction level with 4.52. In the end, patients in their 70s showed highest score with 4.81 in the overall satisfaction and it was also statistically significant. 5. In the overall satisfaction level by interest in dental health, appearance showed highest score with 4.57 and it was also significantly higher than that of whole body. In the variance by dental knowledge, 'well know' group showed highest score with 4.58, and that of 'just a little' group was 4.33. That means there are correlations between dental knowledge and satisfaction level. 6. As a result of analyzing correlations amongst variances of the study, there were strong positive correlations among them. And there were very significantly positive correlations especially between social and psychological function and between psychological and overall satisfaction level. In conclusion, higher psychological function has strong relations with both social function and overall satisfaction level(p<.001).

• Journal of the Korean Institute of Gas
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• v.2 no.4
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• pp.18-24
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• 1998

Polyurethane (PU) synthesized from 4,4'-diphenylmethane diisocyanate having high functionality (f=2.9) and polyester polyol have been investigated by differential scanning calorimeter (DSC), dynamic mechanical thermal analyzer (DMTA), and Fourier transform infrared spectroscope (FT-IR). From the DSC measurement of polyurethane, a single transition temperature ($T_g$) was observed. This result indicates that polyurethanes synthesized in this work have homogeneous network structure due to high functionality of diisocyanate. It was also found that the $T_g$ of polyurethane was increased as hard segment content was increased. The results from DMTA measurement are consistent with DSC results. In order to investigate the effect of thermal annealing on the $T_g$ of polyurethane, the samples were annealed at various annealing conditions. $T_gs$ of polyurethanes were found to increased with annealing temperature. From swelling experiment and FT-IR studies, it was found that the $T_g$ was increased as crosslinking density of polyurethane was increased.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.37-37
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• 2021

Calystegia soldanella L. is a perennial herbaceous halophyte belonging to the convolvulaceae family, which mainly grows in coastal sand dunes in Korea. Shoots and rhizomes are edible, and roots called 'Hyoseon Chogeun' are known to have medicinal effects such as antipyretic, sterilization, and diuretic. In addition, physiological activities of antioxidant, anti-inflammatory, antiviral, antifungal and PTP-1B (protein tyrosine phosphate-1B) inhibition have been reported. In this study, in vitro induction cell lines of C. soldanella L. collected from the coastal sand dunes in Jeju island was redifferentiated into adventitious roots that can be used as medicinal resources. Also the biomass of mass-proliferated adventitious roots using a bioreactor were evaluated. Plants of C. soldanella L. were collected from the crevice of the seashore in the coastal area of Taeheung 2-ri, Namwon-eup, Seogwipo-si. Then, it was separated into leaves, stems, rhizomes, and roots, and surface sterilized with 70% ethyl alcohol and 2% NaOCl (sodium hypochlorite). After washing with sterilized water, each organ section was cultured in Hormone-free MS medium (Murashige & Skoog Medium). As a result, the induction response rates were evaluated at 85% and 55%, respectively, in terms of callus formation and shoot generation in the rhizome segment. In the case of the adventitious roots morphological characteristics induced by single-use treatment of auxin-based plant growth regulators IBA and NAA from redifferentiated shoots were compared. Most efficient adventitious root culture method as a rooting rate, number, length, and biomass proliferation in the bioreactor system was confirmed when treated by culturing in MS salts, Sucrose 30 g·L^-1, and IBA 1mg·L^-1 for 4 weeks. In this study, the medium composition and culture period were confirmed using a bioreactor system to mass-proliferate adventitious roots derived from C. soldanella L. in Jeju island. Also this adventitious root line developed a new medicinal material could increase value of the bio-industry ingredient through quantitative and qualitative screening of phyto-bioactive compounds.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.183-189
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• 2023

This paper proposes a new JPEG format, All-in-JPEG, which can include not only multiple photos but also various media such as audio and text by extending the JPEG format. All-in-JPEG add images, audio, and text at the existing JPEG file, and stores meta information by utilizing the APP3 segment of JPEG. With All-in-JPEG, smartphone users can save many pictures taken in burst shots in one file, and it is also very convenient to share them with others. In addition, you can create a live photo, such as saving a short audio at the time of taking a photo or moving a part of the photo. In addition, it can be used for various applications such as a photo diary app that stores images, voices, and diary text in a single All-in-JPEG file. In this paper, we developed an app that creates and edits All-in-JPEG, a photo diary app, and a magic photo function, and verified feasibility of the All-in-JPEG through them.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.4
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• pp.233-252
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• 2021

This paper is a study to improve the efficiency of mixing technology in the shield TBM chamber. Currently, the number of construction cases using the TBM method is increasing in Korea. According to the increasing use of TBM method, research on TBM method such as Disc Cutter, Cutter bit, and Segment also shows an increasing trend. However, there is little research on the mixing efficiency in chamber and chamber. In order to improve the smooth soil treatment and the behavior of the excavated soil, a study was conducted on the change of the mixing efficiency according to the effective mixing bar arrangement in the chamber. In the scale model experiment, the ground was composed using plastic materials of different colors for ease of identification. In addition, the mixing bar arrangement was different and classified into 4 cases, and the particle size distribution was classified into single particle size and multiple particle size, and the experiment was conducted with a total of 8 cases. The rotation speed of the cutter head of all cases was the same as 5 RPM, and the experiment time was also carried out in the same condition, 1 minute and 30 seconds. In order to check the mixing efficiency, samples at the upper, middle (left or right), and lower positions of each case were collected and analyzed. As a result of the scaled-down model experiment, the mixing efficiency of Case 4 and Case 4-1 increased compared to Case 1 and Case 1-1, which are actually used. Accordingly, it is expected that the mixing efficiency can be increased by changing the arrangement of the mixing bar in the chamber, and it is considered to be effective in saving air as the mixing efficiency increases. Therefore, this study is considered to be an important indicator for the use of shield TBM in Korea.