• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.2
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• pp.113-125
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• 2007

Improved numerical method to obtain the exact stiffness matrices is newly proposed to perform the spatially coupled elastic and stability analyses of non-symmetric and open/closed thin-walled beam on elastic foundation. This method overcomes drawbacks of the previous method to evaluate the exact stiffness matrix for the spatially coupled stability analysis of thin-walled beam-column This numerical technique is accomplished via a generalized eigenproblem associated with 14 displacement parameters by transforming equilibrium equations to a set of first order simultaneous ordinary differential equations. Next polynomial expressions as trial solutions are assumed for displacement parameters corresponding to zero eigenvalues and the eigenmodes containing undetermined parameters equal to the number of zero eigenvalues are determined by invoking the identity condition. And then the exact displacement functions are constructed by combining eigensolutions and polynomial solutions corresponding to non-zero and zero eigenvalues, respectively. Consequently an exact stiffness matrix is evaluated by applying the member force-deformation relationships to these displacement functions. In order to illustrate the accuracy and the practical usefulness of this study, the numerical solutions are compared with results obtained from the thin-walled beam and shell elements.

• Journal of Chest Surgery
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• v.35 no.11
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• pp.807-811
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• 2002

Due to its less invasive nature and superior visual field, video-assisted thoracescopic excision of mediastinal mass is thought to be comparable to open thoracotomy. Material and Method : From January 1995 to August 2001, the medical records of 38 patients who underwent video-assisted thoracoscopic excision of mediastinal mass was retrospectively analyzed. The outcome of these patients were compared with 5 patients who converted to thoracotomy Result: Male to female ratio was 13(34.2%) : 25(65.8%), and mean age was 39.2$\pm$35.4 years. Regarding the pathology, there were 8 neurilemmomas(21.1%), 6 thymic cysts (15.8%), 5 teratomas(13.2%), 5 ganglioneuromas(13.2%), 4 bronchogenic cysts(10.5%), 3 pericardial cysts(7.9%), 3 thymomas(7.9%), and 2 lymphangiomas(5.3%). The mean operation time was 110.6$\pm$7.0 minutes, mean postoperative tube stay was 4.2$\pm$0.4 days, mean postoperative hospital stay was 5.2$\pm$0.4 days, and mean number of injection of analgesics was 1.9$\pm$0.4 times. Although the mean values for the above indices were less than those of the thoracotomy conversion cases, they were statistically insignificant. Postoperative complications of videoassisted thoracoscopic excision included chylothorax, prolonged air leakage, and unilateral phrenic nerve palsy, all of which recovered before patient discharge. There was, however, permanent unilateral ptosis in one patient. Conclusion : As video-assisted thoracoscopic excision of mediastinal mass is safe, less painful, conducive to earlier recovery and cosmetically more appealing, a more active application of this technique is recommeded.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.4
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• pp.433-445
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• 2010

The aim of this study was to evaluate the fixation effect by connecting impression copings and to compare the three types of impression trays which were used in open tray impression technique. Experimental groups used 3 types of impression trays which are custom tray, plastic metal combination tray and polycarbonate stock tray. These three groups were subdivided into splinted and non-splinted impression copings group. The total number of experimental groups was six. 10 specimens were made for each group. We used 1-screw test, observing the specimen on which only one side abutment of reference framework was fixated with 20 Ncm. The gap between implant analogue and abutment of the other side was observed by stereo microscope. It was measured at 6 points in each specimen. Measuring value was selected when same result was revealed 3 times. Recorded data were statistically analyzed. Whether impression copings were splinted or not, there was no significant difference among custom tray group, plastic metal combination tray group, and polycarbonate stock tray group. Significant statistical difference in vertical fit discrepancy was found between splinted and non-splinted impression copings group with custom tray, plastic metal combination tray and polycarbonate stock tray (p<0.05).

• Journal of Navigation and Port Research
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• v.39 no.1
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• pp.7-13
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• 2015

The number of mobile terminals equipped with a GPS module is steadily increasing today. However, because they using code pseudorange measurements in positioning, the positioning accuracy of mobile terminals is lower than that of those receivers using carrier phases. Especially, the multipath signal causes more significant errors in code pseudoranges. Therefore, the techniques of multipath detection and elimination is necessary. In this study, as an initial analysis of multipath detection and elimination technique development, we tested the feasibility of multipath signal detection using GPS signal strength information. We found that the GPS signal strength increases as the elevation angle gets higher in the open-sky environment. Also, we found that the signal strength decreases when there were some signal reflectors nearby. We checked the repeatability of the signal strength variation characteristics by reflecting repeat time of GPS satellites. As a result, this characteristics repeats almost perfectly when GPS satellites pass the same orbit. Therefore, we found that it is not a temporary phenomenon and the multipath signal detection should be possible by using GPS signal strength information.

• Journal of Korea Water Resources Association
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• v.41 no.8
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• pp.761-772
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• 2008

The object of this study is to develop the model that solves the numerically difficult problems in hydraulic engineering and to demonstrate the applicability of this model by means of various test examples, such as, verification in the gradually varied unsteady condition, three steady flow problems with the change of bottom slope with exact solution, and frictional bed with analytical solution. The governing equation of this model is the integral form of the Saint-Venant equation satisfying the conservation laws, and finite volume method with the Riemann solver is used. The evaluation of the mass and momentum flux with the HLL Riemann approximate solver is executed. MUSCL-Hancock scheme is used to achieve the second order accuracy in space and time. This study introduce the new and simple technique to discretize the source terms of gravity and hydrostatic pressure force due to longitudinal width variation for the balance of quantity between nonlinear flux and source terms. The results show that the developed model's implementation is accurate, robust and highly stable in various flow conditions with source terms, and this model is reliable for one-dimensional applications in hydraulic engineering.

• The Journal of Korean Institute for Practical Engineering Education
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• v.2 no.2
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• pp.1-9
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• 2010

This research was conducted as a part of a research project entitled 'A Fact-finding Survey and Improvement Method for Practical Engineer'. The aim of this research is to explore the educational development strategy for KUT, which is the Korea's leading university of practical engineering, by setting the relevant educational goal for training practical engineer and evaluating the core competencies of practical engineer as well as professors. The research is categorized as follow: the direction to be differentiated from other universities, the core competencies of practical engineer, the core curriculum for the training of practical engineer, professors's competencies for training of practical engineer, developing strategy for establishing the identity of KUT. Delphi technique was applied for survey and selected 32 panels including directors of Korean Institute for Practical Engineering Education, KUT professors and outside experts were involved in that survey. Delphi survey was conducted for three times. In the first survey, suggestions on five categories from an open questionnaire were summarized into 73 questions. 2nd and 3rd questionnaires were developed using the summarized questions, distributed and collected by email, thereafter, the suitability and necessity of each item were rated in five-point Likert scale, calculated and analyzed the results.

• Journal of Distribution Science
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• v.11 no.10
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• pp.81-92
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• 2013

Purpose - This study empirically analyzes the effect of improvements in the quality of service management performance of college education on traders' conscious change of business management innovation and diverse sales expertise for a year. The use of traders' conscious changes and sales expertise as variables for the verification of the effects of parameters related to the active trader's traditional education market is a desirable direction. The method of research reflects the quality of education service, management result, traders' conscious changes, and sales expertise to understand the precise essence and definition of teaching quality at merchant colleges through theoretical consideration. Moreover, its impact on traders' conscious changes and sales expertise in empirical analysis acts as an intermediary. Research design, data, methodology - The hypothesis of this study leverages the SPSS statistical program. To gather actual proof, sample survey for theoretical research examined 262 valid papers of the 300 papers written by 10 merchants who graduated from merchant's university. First, using the SERVQUAL model, Parasuraman et al. (1996) indicated that for quality of education service, the configuration of factors is the same as the sympathetic performance, that is, responsiveness and empathy, and traders are aware of these elements. However, our preliminary investigation revealed that traders' university education has been excluded as a component of quality of service in the earlier studies. Moreover, we found that certainty of knowledge, reliability, and sympathy are influenced by challenges and by the changing intentions of merchant consciousness. In addition, our study confirms that improvements in convincing abilities and sales technique have a positive impact. Second, merchants' and traders' expertise are proven to affect business performance. In other words, university education of traders and merchants affects the consciousness of consumers, and changes patterns of sales. Third, the quality of service management education and change in the consciousness has a considerable impact on the trader, thereby maximizing business performance and acting as an intermediary for verification. Fourth, the quality of service management education affects the trader's sales expertise to maximize business performance. Results - To summarize, the quality of college educational services relates to the improvement of business performance and the role of the resulting virtuous cycle. Consequently, we can look for suggestions in the traditional markets, where the Government pays attention to the exterior environmental factors as well as to the changing business environment. However, the most important aspect is the merchant awareness. That is, a merchant should understand the distribution environment. Several competitor and trend analyses should be conducted to meet customers' expectations positively and proactively cope with any challenges related to changes. Further, expertise in sales and marketing skills need to be acquired to improve customer convincing abilities and develop a customer-oriented mindset. Conclusions - According to the changes in consumption trends of business enterprises, new management techniques are required to survive competition by improving traditional markets, which will necessitate more competitive education programs in merchant universities.

• Journal of Animal Science and Technology
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• v.47 no.4
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• pp.615-624
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• 2005

The cPCR technique was used to monitor rumen fermentation and attachment of Fibrobacter succinogenes to cellulose at different pH in the in vitro culture medium. The target fragments of 16S rDNA(445 bp) were amplified from genomic DNA of F. succinogenes with specific primers and internal controls(205 bp) were constructed. Cell counts were estimated from the amounts of genomic DNA, which was calculated from cPCR results. F. succinogenes in pH 6.8 and 6.2 showed apparently higher attachment than in pH 5.8 during all incubation time. There were some difference between pH 6.8 and 6.2 in the degree of attachment, but the different was not significant (P>0.05). Cellulose degradation increased in process of incubation time and the increasing rate was higher when initial pH was higher. The pH in culture medium decreased regardless of initial pH in course of incubation time. After 24 h of incubation, medium pH was dropped by 0.24, 0.58 and 0.16 units from original medium pH 6.8, 6.2 and 5.8, respectively. More gas was produced at higher initial pH in the same manner as in cellulose degradation. In summery, Initial pH of rumen culture in vitro significantly influenced cellulose digestion, gas production, pH change and bacterial attachment. Especially, low pH(5.8) resulted in much lower bacterial attachment and fiber digestion compared to higher medium pH.

• Clinics in Shoulder and Elbow
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• v.14 no.1
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• pp.117-124
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• 2011

Purpose: We reviewed arthroscopic reconstruction among the several treatment options for anterior shoulder instability with a bony Bankart lesion. Materials and Methods: Although open Bankart repair has long been considered the optimal surgical management of anterior shoulder instability, advancements in arthroscopic techniques have led to a recent shift to arthroscopic Bankart repair. However, for cases of a glenoid bony defect, several authors have reported various methods to accurately measure the amount of bony defect. Results: The arthroscopic technique of bony Bankart reconstruction continues to evolve and various methods have followed. To overcome the limitations of single fixation of a Bankart lesion, arthroscopic dual fixation (2 point fixation) has recently been tried to anatomically repair and restore the rigid fixation of a bony fragment. The concept of performing the Bristow-Latarjet transfer procedure under arthroscopy has also recently emerged. However, a large series of cases and long term follow up are required to prove the better results. Conclusion: To obtain a successful outcome for patients with anterior instability with a glenoid bony defect, it is imperative that the surgeon be aware of the accurate status of the bony defect and the intraoperative, postoperative factors associated with the proper treatment of this unstable pathology.

• Progress in Superconductivity
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• v.13 no.1
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• pp.7-11
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• 2011

The effects of Sm:Ba:Cu composition ratio in SmBCO coated conductor on their superconducting properties were investigated. The SmBCO coated conductors were fabricated by reactive co-evaporation method using EDDC(Evaporation using Drum in Dual Chamber) system. In this system, we could obtain various samples with different composition ratios in a batch by the technique providing composition gradient at deposition zone. From the specimens prepared by EDDC system, we found that composition ratio is uniform parallel to the drum axis, but gradient along the circumferential direction of the drum. We installed a shield having parallelogram open area between the deposition chamber and the evaporation chamber in EDDC system, and attached a 30 cm long template, which is parallel to drum axis, onto the drum surface. In this configuration, we could obtain SmBCO coated conductors having a gradient composition along the length of template. We measured the composition ratios and surface morphologies with periodic interval by SEM and EDAX, and confirmed the profile of composition ratio. We also measured critical current using non-contact Hall probe critical current measurement system and thereby could plot composition ratio vs. critical current. The maximum critical current was obtained, and the surface morphology with the shape of roof tile was observed at the corresponding composition ratio of Sm:Ba:Cu = 1.01:1.99:4.87. It was also found that composition ratio had an effect on not only critical current but also surface morphology.