• Journal of Biomedical Engineering Research
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• v.25 no.5
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• pp.361-367
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• 2004

The axial compressive strength, relative 3-D stability and osteoconductive shape design of an intervertebral fusion cage are important biomechanical factors for successful intervertebral fusion. Changes in the stress distribution of the vertebral end plate and in cage stability due to changes in the spike shape of a newly contrived box-shaped fusion cage are investigated. In this investigation, the initial contact of the cage's spikes with the end plate and the penetration of the cage's spikes into the end plate are considered. The finite element analysis is conducted to study the effects of the cage's spike height, tip width and angle on the stress distribution of the vertebral end plate, and the micromigration of the cage in the A-P direction. The stress distribution in the end plate is examined when a normal load of 1700N is applied to the vertebra after inserting 2 cages. The micromigration of the cage is examined when a pull out load of l00N is applied in the A-P direction. The analysis results reveal that the spike tip width significantly influences the stress concentration in the end plate, but the spike height and angle do not significantly influence the stress distribution in the end plate touching the cage's spikes. In addition, the analysis results show that the micromigration of the cage can be reduced by adjusting the spike angle and spike arrangement in the A-P direction. This study proposes the optimal shape of an intervertebral fusion cage, which promotes bone fusion, reduces the stress concentration in a vertebral end plate, and increases mechanical stability.

• Journal of Digital Convergence
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• v.14 no.4
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• pp.19-31
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• 2016

With the development of information and communication technologies, a new paradigm in higher education is required. Accordingly, establishing a smart campus has emerged as an important issue in universities worldwide. This study aims to discuss key issues and to provide useful academical and practical implications on smart campus by reviewing related literatures. For this purpose, this study examined recent literatures on smart campus by four research perspectives; 1) learning/knowledge-centric approach, 2) technology-centric approach, 3) integrated approach, and 4) user-centric approach, then developed smart campus framework. Smart campus user criteria contained members of university as well as local community and business stockholders. Smart campus framework presented specific service areas each belongs to smart education, smart life and smart administration domains and motivating factors of using smart campus. Moreover, by considering key issues and problems raised in previous studies, this study suggested practical implications for successful development of smart campus.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.1
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• pp.61-77
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• 2005

Statement of problem. The implant prosthesis has been utilized in various clinical cases thanks to its increase in scientific effective application. The relevant implant therapy should have the high success rate in osseointegration, and the implant prosthesis should last for a long period of time without failure. Resorption of the peri-implant alveolar bone is the most frequent and serious problem in implant prosthesis. Excessive concentration of stress from the occlusal force and biopressure around the implant has been known to be the main cause of the bone destruction. Therefore, to decide the location and angulation of the implant is one of the major considering factors for the stress around the implant fixture to be dispersed in the limit of bio-capacity of load support for the successful and long-lasting clinical result. Yet, the detailed mechanism of this phenomenon is not well understood. To some extent, this is related to the paucity of basic science research. Purpose. The purpose of this study is to perform the stress analysis of the implant prosthesis in the partially edentulous mandible according to the different nature locations and angulations using three dimensional finite element method. Material and methods, Three 3.75mm standard implants were placed in the area of first and second bicuspids, and first molar in the mandible Thereafter, implant prostheses were fabricated using UCLA abutments. Five experimental groups were designed as follows : 1) straight placement of three implants, 2) 5$^{\circ}$ buccal and lingual angulation of straightly aligned three implants, 3) 10$^{\circ}$ buccal and lingual angulation of straightly aligned three implants. 4) lingual offset placement of three implants, and 5) buccal offset placement of three implants. Average occlusal force with a variation of perpendicular and 30$^{\circ}$ angulation was applied on the buccal cusp of each implant prosthesis, followed by the measurement of alteration and amount of stress on each configurational implant part and peri-implant bio-structures. The results of this study are extracted from the comparison between the distribution of Von mises stress and the maximum Von mises stress using three dimensional finite element stress analysis for each experimental group. Conclusion. The conclusions were as follows : 1. Providing angulations of the fixture did not help in stress dispersion in the restoration of partially edentulous mandible. 2. It is beneficial to place the fixture in a straight vertical direction, since bio-pressure in the peri-implant bone increases when the fixture is implanted in an angle. 3. It is important to select an appropriate prosthodontic material that prevents fractures, since the bio-pressure is concentrated on the prosthodontic structures when the fixture is implanted in an angle. 4. Offset placement of the fixtures is effective in stress dispersion in the restoration of partially edentulous mandible.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.4
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• pp.433-453
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• 1999

There are a lot of elements affecting the success of implant prosthesis. The quality of surgical procedure is considered as one of the key factors. To avoid the excess heat generation is an important element of successful osseointegration and it can be achieved by using a gentle surgical technique with a sharp instrument in bone drilling. This study was performed to measure and analyze comparatively the heat transmitted to sur-rounding bone at a distance of 0.5mm from the periphery of the drill hole in each drilling stage. The results were as follows. In standard system, the temperature of surrounding bone tissue ranged from $29.2^{\circ}C\;to\;48.3^{\circ}C$ with irrigation and from $34.6^{\circ}C\;to\;84.3^{\circ}C$ without irrigation. And in wide system, the temperature of surrounding bone tissue ranged from $29.5^{\circ}C\;to\;52.5^{\circ}C$ with irrigation and from $34.8^{\circ}C\;to\;87.8^{\circ}C$ without irrigation. And the temperature ranges exceeded the threshold without irrigation, while showing less than the threshold by the cooling effect of irrigation. In comparing standard system with wide system, although there was no significant difference, ${\phi}4.3mm$ pilot and ${\phi}4.3mm$ twist drill of wide system showed high value and wide system showed slightly high elevation of temperature in all depth in fixture installation. In the finite element analysis, the calculated value by the Fourier's cooling law were applied to the bone drilling surface. And through analysis using different irrigation temperatures at $28^{\circ}C,\;15^{\circ}C\;and\;5^{\circ}C$, and according to the time. The result was that the cooling water at least below $15^{\circ}C$ was required to maintain the temperature of surrounding bone less than threshold in bone drilling, the cooling water below $5^{\circ}C$ was required to gain more sufficient cooling effect, and cooling over 5 seconds was needed after bone drilling for sufficient effect.

• Journal of Periodontal and Implant Science
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• v.27 no.1
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• pp.117-128
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• 1997

Using barrier membrane, guided bone regeneration(GBR) and guided tissue regeneration(GTR) of periodontal tissue are now widely studied and good results were reported. In bone regeneration, not all cases gained good results and in some cases using GTR, bone were less regenerated than that of control. The purpose of this study is to search for the method to improve the success rate of GBR and GTR by examination of the cause of the failure. For these study, rats and beagle dogs were used. In rat study, 5mm diameter round hole was made on parietal bone of the rat and 10mm diameter of bioresorbable membrane was placed on the bone defects and sutured. In 1 ,2, 4 weeks later, the rats were sacrificed and Masson-Trichrome staining was done and inspected under light microscope for guided bone regeneration. In dog study, $3{\times}4mm^2$ Grade III furcation defect was made at the 3rd and 1th premolar on mandible of 6 beagle dogs. The defects were covered by bioresorbable membrane extending 2-3mm from the defect margin. The membrane was sutured and buccal flap was covered the defect perfectly. In 2, 4. 8 weeks later. the animals were sacrificed and undecalcified specimens were made and stained by multiple staining method. In rats. there was much amount of new bone formation at 2 weeks. and in 4 weeks specimen, bony defect was perfectly dosed and plenty amount of new bone marrow was developed. In some cases, there were failures of guided bone regeneration. In beagle dogs, guided tissue regeneration was incomplete when the defect was collapsed by the membrane itself and when the rate of resorption was so rapid than expected. The cause of the failure in GBR and GTR procedure is that 1) the membrane was not tightly seal the bony defects. If the sealing was not perfect, fibrous connective tissue infiltrate into the defect and inhibit the new bone formation and regeneration. 2) the membrane was too tightly attached to the tissue and then there was no space to be regenerated. In conclusion, the requirements of the membrane for periodontal tissue and bone regeneration are the biocompatibility, degree of sealingness, malleability. space making and manipulation. In this animal study. space making for new bone and periodontal ligament, and sealing the space might be the most important point for successful accomplishment of GBR and GTR.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.2
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• pp.189-198
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• 1998

Since the male sterilization (vasectomy) has been performed on a large scale as an accepted family planning in Korea on 1980s and this, in turn, has been followed by an increase in the number of patients requesting vasovasostomy. We studies 1000 consecutive cases of vasovasostomy performed from January 1975 to July 1995 in Pusan National University Hospital. In this report, we are going to present serial studies of vasovasostomy through which we attempted to find out what factors are of impotence in influencing the successful outcome of vasovasostomy operation. We inquired the operative results data through the questionnaire and telephone interview with survey of medical records. A total of 259 cases was excluded due to the loss of follow-up. The overall patency and pregnancy rates of 741 cases were 86.9% and 51.1%, respectively. The age of man at the time of anastomosis ranged from 23 to 57 years old with an average of 34.9. The most frequent reason for requesting vasovasostomy was the desire to have more children (43.4%). The average obstructive interval was 60.6 months with range from 1 to 264 months. If the obstructive interval had been less than 5 years patency rate was 92.4% and pregnancy rate 64.8%, but 6 years or more 84.1% and 48.5% (p<0.01, p<0.01). Patency and pegnancy rates according to intraoperative vas fluid were 93.1% and 62.8% for presence and 83.7% and 53.1% for absence (p<0.01, p<0.05). Patency and pregnancy rates according to histologically proven sperm granuloma at vasectomy site were 87.7% and 49.2% for presence and 86.9% and 50.6% for absence (p>0.05, p<0.05). Patency and pregnancy rates were not significantly different between microscopic standard vasovasostomy (88.4%, 64.3%) and modified vasovasostomy (89.5%, 56.3%)(p>0.05, p>0.05). Both patency and pregnancy rates according to level of anastomosis were 89.8% and 59.8% in cases of straight vas and 91.5%, 60.1% in cases of convoluted vas (p>0.05, p>0.05). Patency and pregnancy rates according to the kind of suture materials were 91.5% and 56.2% for absorbable, 91.0% and 64.2% for non-absorbable and 93.3% and 53.3% for absorbable plus non-absorbable, respectively (p>0.05, p<0.05). Thus it is suggested that the important factor influencing the success rate of vasovasostomy is the interval of obstruction and vasal ooze with surgical skills.

• Clinical and Experimental Reproductive Medicine
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• v.29 no.4
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• pp.287-294
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• 2002

Objectives: Pelvic tuberculosis (TB) causes infertility despite of anti-TB chemotherapy and IVF-ET is effective treatment to achieve pregnancy. The aim of this study is to assess the outcomes of IVF-ET in pelvic TB, especially according to main Tb lesion, and to investigate the factors affecting the successful outcome. Methods: A total of 135 IVF-ET cycles were performed in 54 patients with pelvic TB and the outcome was compared with that of control group with tubal factor not associated with TB in 301 cycles, 227 patients. Anti-TB chemotherapy was performed in the patients with pelvic TB. Pregnancy rate was compared according to main TB lesion as salpingitis, peritonitis, and endometritis. In the patients with endometrial TB, when complicated with uterine synechia, hysteroscopic lysis was done before IVF-ET and pregnancy rate was compared according to the presence of uterine synechia. Results: There was no significant difference in peak E2 ($2,790{\pm}280.1$ vs $2,554{\pm}101.2$, p>0.05), the number of retrieved oocytes ($13.5{\pm}0.7$ vs $12.5{\pm}0.4$, p>0.05) and fertilized oocytes ($7.7{\pm}0.5$ vs $7.8{\pm}0.3$, p>0.05) between patient and control group. Clinical pregnancy rate per transfer in pelvic TB group was 22.9% and showed no difference from that of control group (24.3%, p>0.05). Although it was not statistically significant, pregnancy rate in the endometrial Tb (18%) was lower than that in the salpingitis (28.5%) or peritonitis (26.5%) (p>0.05). In the endometrial TB with uterine synechia, pregnancy rate was significantly lower than that of the patients without synechia even after hysteroscopic lysis (9.7% vs 31.6%, p<0.05). Conclusion: IVF-ET after anti-TB chemotherapy is the most effective treatment to achieve pregnancy in infertile patients with pelvic TB. Because the presence of endometrial TB and resulting uterine synechia affects the outcome of IVF-ET, thorough evaluation for endometrium with endometrial biopsy and hysteroscopy is important to predict the prognosis of IVF-ET treatment.

• Journal of Digital Convergence
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• v.14 no.6
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• pp.93-107
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• 2016

The purpose of this study is to consider how the competency of management consultants and completion index of consulting. influences the management performance. For this research. we chose 500 small & medium enterprises located all over the country that have implemented management consulting in recent 3 years. And we have done survey for the employees. and gathered and analyzed 294 samples. The result of research is as follows. First, Job competency of management consultants have reliable influence on the business performance and organization effectiveness. Second, Job competency and Common competency of management consultants have reliable influences on the completion index of consulting. Third, Job competency of management consultants and completion index of consulting have reliable influences on management performance. Fourth, Completion index of consulting have mediated job competency of consultants and management performance. Fifth, the impact was estimated that the more manager supporting is, the more job competency of consultant have an effect on organization effectiveness. These findings suggest that through the efficient way to perform successful consulting and identify an association between factors, it can contribute to small & medium enterprise management consulting activated.

• Management & Information Systems Review
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• v.33 no.1
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• pp.17-43
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• 2014

research tries to present the role of perceived justice and authenticity in service recovery process. Prior research on the service recovery have focused on relationship among perceived justice, recovery satisfaction and positive customer behavior. Especially perceived justice including distributive, procedural, and interactional justice has addressed as most important antecedents of recovery satisfaction. Although the pivotal role of perceived justice for successful service recovery has agreed by many researchers, relatively little attention has been paid to emotional aspect of customer. During the service recovery process, even if customer perceived recovery effort from service provider as justice one, they might feel displeasure or dissatisfaction. It means prior researches have underestimated the importance of emotional aspect while they focus on cognitive aspects. The one research focused on emotional aspects examined effect of authenticity in service context with other related factors. However, solely examined effect of authenticity is not enough to present proper implication effect between justice and authenticity so that it can be understood more clearly. In this study, we examined customer reactions to service failure and recovery process in restaurant service settings. Specifically, we focused on the moderating effect of authenticity on the paths between perceived justice and outcome variables such as forgiveness and recovery satisfaction.

• KIISE Transactions on Computing Practices
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• v.21 no.1
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• pp.13-18
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• 2015

Computational science simulations have been used to enable discovery in a broad spectrum of application areas, these simulations show irregular demanding characteristics of computing resources from time to time. The adoption of virtualized high performance cloud, rather than CPU-centric computing platform (such as supercomputers), is gaining interest of interests mainly due to its ease-of-use, multi-tenancy and flexibility. Basically, provisioning a virtual cluster, which consists of a lot of virtual machines, in a real-time has a critical impact on the successful deployment of the virtualized HPC clouds for computational science simulations. However, the cost of concurrently creating many virtual machines in constructing a virtual cluster can be as much as two orders of magnitude worse than expected. One of the main factors in this bottleneck is the time spent to create the virtual images for the virtual machines. In this paper, we propose a novel technique to minimize the creation time of virtual machine images and improve I/O performance of the provisioned virtual clusters. We also confirm that our proposed technique outperforms the conventional ones using various sets of experiments.