• Journal of Korean Neurosurgical Society
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• v.46 no.6
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• pp.532-537
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• 2009

Objective : Recently, motion preservation has come to the forefront of emerging technologies in spine surgery. This is the important background information of the emergence of cervical arthroplasty as an alternative to arthrodesis that offers the promise of restoring normal spinal movement and reduces a kinematic strain on adjacent segments. The study was designed to evaluate early surgical outcome and radiological effects of $Bryan^{(R)}$ cervical disc prosthesis. Methods : The authors retrospectively reviewed radiographic and clinical outcomes in 52 patients who received the $Bryan^{(R)}$ Cervical Disc prosthesis, for whom follow-up data were available. Static and dynamic radiographs were measured by computer to determine the angles formed by the endplates of the natural disc preoperatively, those formed by the shells of the implanted prosthesis, the angle of functional spine unit (FSU), and the C2-7 Cobb angle. The range of motion (ROM) was also determined radiographically, whereas clinical outcomes were assessed using Odom's criteria, visual analogue pain scale (VAS) and neck disability index (NDI). Results : A total of 71 $Bryan^{(R)}$ disc were placed in 52 patients. A single-level procedure was performed in 36 patients, a two-level procedure in 13 patients, and a three-level procedure in 3. Radiographic and clinical assessments were made preoperatively. Mean follow-up duration was 29.2 months, ranging from 6 to 36 months. All of the patients were satisfied with the surgical results by Odom's criteria, and showed significant improvement by VAS and NDI score (p < 0.05). The postoperative ROM of the implanted level was preserved without significant difference from preoperative ROM of the operated level (p < 0.05). 97% of patients with a preoperative lordotic sagittal orientation of the FSU were able to maintain lordosis. The overall sagittal alignment of the cervical spine was preserved in 88.5% of cases at the final follow up. Interestingly, preoperatively kyphotic FSU resulted in lordotic FSU in 70% of patients during the late follow up, and preoperatively kyphotic overall cervical alignment resulted in lordosis in 66.6% of the patients postoperatively. Conclusion : Arthroplasty using the $Bryan^{(R)}$ disc seemed to be safe and provided encouraging clinical and radiologic outcome in our study. Although the early results are promising, this is a relatively new approach, therefore long-term follow up studies are required to prove its efficacy and its ability to prevent adjacent segment disease.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.1 no.2
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• pp.101-134
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• 2006

This study is conducted to examine how purchase behaviors of consumers have affected by the promotion of coupons in internet shopping mall. This study was conducted with the purpose of identifying the differences In purchase behavior based on consumer's perception and experience of internet shopping mall coupons, and based on consumers' perception of cost and value of coupons, using a theoretic framework presented in previously conducted studies. The results of this study can be summarized as follows. First, based on the perception of coupons, there were significant differences in intent to use and intent to re-use at the time when coupons are offered, and at the time when coupons are offered, no significant differences were found between the level of interest and the importance of coupon at the time of visiting the shopping mall; however, significant differences were found in the overall purchase behavior based on perception of coupons. Second, when overall differences In purchase behavior based on experience in coupon use was observed, having experience in using coupons showed a higher average than did having no experience in using coupons, showing a significant difference. It was found that compared to those without experience in using coupons, those with experience with coupons had higher intent to use at the time when coupon is offered, intent to re-use at the time when coupon is offered, and higher level of purchase behavior In the importance of coupons at the time of visiting the shopping mall. Third, when relationship between purchase behaviors, cost of coupon, and perception of convenience was observed, a clear static relationship was found. This suggests that as the cost and perception of convenience of coupon increases, purchase behavior also increases. Such result suggests that there is a difference in purchase behavior based on experience in coupon use. When relationship of purchase behavior by variables of cost of coupon and perception of convenience is observed, it has a positive relationship with the perception that the use of coupon includes saving money, financial help, enjoyment of use, habitual use, has a short effective date, and has a negative relationship with the perception that it saves little money and is a waste of time. Therefore, it can be seen that purchase behavior has the highest relationship with enjoyment of coupon use and habitual coupon use. Such results suggest that purchase behavior will be significantly influenced based on cost of coupon and perception of convenience.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.705-713
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• 2018

An automotive ball joint connects the suspension system to the steering system and helps to enable rotational and linear motion between the two elements for steering. This study examines a ball joint used in medium and large-sized pickup trucks. Ball joints consist of a stud, socket, bearing, and plug. The main structural performance metrics of ball joints are the pull-out strength and push-out strength. These structural parameters must meet certain criteria to avoid serious accidents. Test and simulation methods are used to investigate the design requirements, but tests are time-consuming and costly. In this study, we modeled ball joints in SolidWorks and performed a finite element analysis in Abaqus to predict structural performance. The analysis was used to obtain the structural performance required for the static analysis of a 2D axisymmetric model. The uncertainties in the manufacturing of the ball joint were assumed to be the manufacturing tolerances, and the dimensional design variables were identified through case studies. The manufacturing tolerances at each level were defined, and the results were compared with experimental results.

• Journal of Science of Art and Design
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• v.12
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• pp.5-41
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• 2007

As public attention on Well-being culture increases, it is now considered to be a new trend of modern society. The purpose of this study is to publicize the necessity of design products which are advanced in quality and encourage the use of it. The researcher judged that study on design of lighting product to adopt well-being trend is in preliminary level and aims to research on the tendency of well-bing trend and lighting design which the consumer of this age is demanding. As the result of changes in modern consumption trend, design is considered to be a factor of capricious cultural phenomenon. In addition to this, as high technology such as ubiquitous develops with the degitalisation and informatization, the consumer are paying attention to dynamic products rather than static products or products which respond to external stimulus. Products which adopt well-being trend pursuing nature friendly life are particularly preferred It means that not only the basic function of products but also design which satisfy the five sense is required. Modern consumers use products in various way. However, the pro-environmental and human-centered tendency is tried only in very limited area and general study on this matter is extremely rare. This study analyzes the factors which intercepts the adoption of well-being trend to lighting products and seeks for an alternative to solve the problem. Interaction design with well-being trend was adopted to lighting design and the result presented that there is a possibility to differentiate existing lighting design by adding interaction design to the existing lighting design. Therefore, the need for further study on this matter is presented.

• Nuclear Engineering and Technology
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• v.24 no.1
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• pp.98-109
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• 1992

In this study uniaxial cyclic loading tests were performed on Cheon-Ho Mt. Limestone specimens to investigate the fatigue failure behavior. The loading rate was kept constantly at 760kg/$\textrm{cm}^2$/sec under cyclic loading. In order to reveal the fatigue behavior for each rock type, the test results were mutually compared with previous studies carried out on Indiana Limes-tone and Seong-Ju Sandstone. Fatigue data is presented in the form of S-N curves, which illustrate the relationship of maximum applied stress(S) to the number of cycles(N) required to produce failure. For the purpose of comparing the S-N curves for each rock type, the test data were formulated up to 10$^4$cycles and the correlation coefficients(R) on Cheon-Ho Mt. Limestone and Seong-Ju Sandstone specimen are 0.886 and 0.983, respectively. All three rock specimens were found to have shorter fatigue life at higher applied stress levels. The fatigue life for each rock type was considered as no less than 81.5, 70 and 74.8%, for Cheon-Ho Mt. Limestone, Indiana Limestone and Seong-Ju Sandstone, respectively. The comparison in static strength for monotonic loaded specimens and specimens which did not fail even after 10$^4$cycles indicated that the increasing rate of strength was about 6.18 and 10.96% , for Cheon-Ho Mt. Limestone and Indiana Limestone, respectively. Poisson's ratio and volumetric strain for Cheon-Ho Mt. Limestone and Seong-ju Sandstone, tended in all the cases to rapidly increase at higher stress levels and with an increase in number of cycles. This increasing trend becomes rapid and obvious just before failure. Also Poisson's ratio and volumetric strain for each stress level were compared and analyzed at the first cycle and the cycle prior to failure.

• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.595-602
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• 2006

An experimental study was conducted to investigate seismic behaviour of post-tensioned(PT) exterior slab-column connections used for the purpose to resist gravity loads only. For these, 2/3-scale, two PT post-tensioned exterior connections with two different tendon arrangement patterns and one conventional reinforced concrete(RC) exterior connection was tested under quasi-static, uni-directional reversed cyclic loading. During the lateral testing, gravity forces transferred to the column were kept constant to closely simulate a moment to shear ratio of a real building. One of the objectives of this study was to assess the necessity and/or the quantity of bottom bonded reinforcement needed to resist moment reversal which would occur under significant inelastic deformations of the adjacent lateral force resisting systems. The ACI 318 and 352 provisions for structural integrity were applied to provide the bottom reinforcement passing through the column for the specimens. Prior test results were also collected to conduct comparative studies for some design parameters such as the tendon arrangement pattern, the effect of post-tensioning forces and the use of bottom bonded reinforcement. Consequently, the impact of tendon arrangement on the seismic performance of the PT connection, that is lateral drift capacity and ductility, dissipated energy and failure mechanism, was considerable. Moreover, test results showed that the amount of bottom reinforcement specified by ACI 352. 1R-89 was sufficient for resisting positive moments arising from moment reversal under reversed cyclic loads. Shear strength of the tested specimens was more accurately predicted by the shear strength equation(ACI 318) considering the average compressive stress over the concrete($f_{pc}$) due to post-tensioning forces than that without considering $f_{pc}$.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.4
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• pp.679-700
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• 1996

Inferior alveolar nerve dysfunction may be the result of trauma, disease, or iatrogenic injury. Inferior alveolar nerve injury is inherent risk in endodontic therapy, orthognathic surgery of the mandible, and extraction of mandibular teeth, particularly the third molars. The sensory disturbances of inferior alveolar nerve associated with such injury have been well documented clinical problem that is commonly evaluated by several clinical sensory test including Tinels sign, Von Frey test(static light touch detection), directional discrimination, two-point discrimination, pin pressure nociceptive discrimination, and thermal test. These methods used to detect and assess inferior alveolar nerve injury have been subjective in nature, relying on the cooperation of the patients. In addition, many of these techniques are sensitive to differences in the examiners experience and skill with the particular technique. Data obtained at different times or by different examiners are therefore difficult to compare. Prior experimental studies have used electro diagnostic methods(sensory evoked potential) to objectively evaluate inferior alveolar nerve after nerve injury. This study was designed with inferior alveolar nerve of rabbit. Several types of injury including mind, moderate, severe compression and perforation with 19 gauze, 21 gauze needle and 6mm, 10mm traction were applied for taking the sesory evoked ppterntial. Latency and amplitude of injury rabbit inferior alveolar nerve were investigated with sensory evoked potential using unpaired t-test. The results were as follows : 1. Intensity of threshold (T1) was $128{\pm}16{\mu}A$ : latency, $0.87{\pm}0.07$ microsecond : amplitude, $0.4{\pm}0.1{\mu}V$ : conduction velocity, 23.3 m/s in sensory evoked potential of uninjured rabbit inferior alveolar nerve. 2. Rabbit inferior alveolar nerve consists of type II and III sensory nerve fiber. 3. Latency was increased and amplitude was decreased in compression injury. The more injured, the more changed in latency and amplitude. 4. Findings in perforation injury was similar to compression injury. Waveform for sensory evoked potential improved by increasing postinjured time. 5. Increasing latency was prominent in traction injury rabbit inferior alveolar nerve. 6. In microscopic histopathological findings, significant degeneration and disorganization of the internal architecture were seen in nerve facicle of severe compression and 10mm traction group. From the above findings, electrophysiological assessment(sensory evoked potential) of rabbit injured inferior alveolar nerve is reliable technique in diagnosis and prognosis of nerve injury.

• Journal of the Korea Concrete Institute
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• v.18 no.3 s.93
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• pp.347-354
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• 2006

In this paper we have attempted to bring the wavelet transform theory to the dynamic response conversion algorithm. This algorithm is proposed for the problem of estimating the displacement data by defining the transformed responses. In this algerian, the displacement response can be obtained from the measured acceleration records by integration without requiring the knowledge of the initial velocity and displacement information. The advantage of the wavelet transform over either a pure spectral or temporal decomposition of the signal is that the pertinent signals features can be characterized in the time-frequency plane. In the response conversion procedure using the wavelet decomposition signals, not only the static component can be extracted, but also the dynamic displacement component can be separated by the structural mode from the identified displacement response. The applicability of the technique is tested by an example problem using the real bridge's superstructure under several cases of moving load. If the reliability of the identified responses is ensured, it is expected that the proposed method for estimating the impact factor can be useful in the bridge's dynamic test. This method can be useful in those practical cases when the direct measurement of the displacement is difficult as in the dynamic studies of huge structure.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.3
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• pp.255-265
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• 2009

Recently many studies have been published on application of immediate loaded implants. However, the immediate loading protocol has not been well documented. The purpose of the present study was to evaluate the stress distribution between bone-implant interfaces and the effect of implant length in the anterior maxilla using 3 dimensional finite element analyses. The diameter 4.0 mm threaded type implants with different length(8.5 mm, 10.0 mm, 11.5 mm, 13.0 mm, 15.0 mm) were used in this study. The bone quality of anterior maxillary bone block was assumed to D3 bone. Bone-implant interfaces of immediately loaded implant were constructed using a contact element for simulating the non osseointegration status. For simplification of all the processing procedures, all of the material assumed to be homogenous, isotropic, and linearly elastic. The 178 N of static force was applied on the middle of the palatoincisal line angle of the abutment with $120^{\circ}$ angle to the long axis of abutment. Maximum von Mises stress were concentrated on the labial cortical bone of the implant neck area, especially at the cortical-cancellous bone interfaces. Compared the different length, highest peak stress value was observed at the 8.5 mm implants and the results indicated a tendency towards favorable stress distribution on the bone, when the length was increased. Presence of cortical bone was very important to immediate loading, and it appears that implants of a length more than 13 mm are preferable for immediate loading at the anterior maxilla.

• Korea journal of population studies
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• v.30 no.3
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• pp.107-135
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• 2007

This paper uses a static Gamma count model, a traditional hurdle model and an endogenous switching Poisson model, respectively for determining married women's completed fertility rates in Korea. This paper analyzes the impact of household income, women's wage and education, and women's job market participation on the number of children of married women above age 40 and on the expected number of children of women aged below 40. The paper shows that a household income significantly increases the number of children for at least women aged above 40, however, this income effect is disappearing for younger generation. The empirical model suggests that women having a job tend to have fewer children for a group 39 years old and below and find that there is an endogeneity problem between child birth and labor force participation, too. The education level of married women gives a positive effect for giving a birth, itself, while it gives a negative impact on the number of children. Based on the empirical results, it concludes that Becker's Quantity-Quality theory works for Korea, too.