• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.445-456
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• 2009

Statement of problem: Many studies have been conducted to improve the primary stability of implants by providing bioactive surfaces via surface treatments. Increase of surface roughness may increase osteoblast activity and promote stronger bonding between bone and implant surface and it has been reported that bioactive surface or titanium can be obtained through alkali and heat treatment. Purpose: The purpose of this study was to evaluate the stability of alkali and heat treated implants via histomorphometric analysis. Material and methods: Specimens were divided into three groups; group 1 was the control group with machined surface, the other groups were treated for 24 hours in 5 M NaOH solution and heat treated for 1 hour at $600^{\circ}C$ in the atmosphere (group 2) and vacuum (group 3) conditions respectively. Surface characteristics were analyzed and fixtures were implanted into rabbits. The specimens were histologically and histomorphometrically compared according to healing periods and change in bone composition were analyzed with EPMA (Electron Probe Micro Analyzer). Results: 1. Groups treated with alkali and heat showed increase of oxidization layer and Na ions. Groups 2 which was heat treated in atmosphere showed significant increase of surface roughness (P<.05). 2. Histomorphometric analysis showed significant increase in BIC (bone to implant contact) according to increase in healing period and there was significant increases in groups 2 and 3 (P<.05). 3. BA(bone area) ratio showed similar results as contact ratio, but according to statistical analysis there was significant increase according to increase in healing period in group 2 only (P<.05). 4. EPMA analysis revealed no difference in gradation of bone composition of K, P, Ca, Ti in surrounding bone of implants according to healing periods but groups 2 and 3 showed increase of Ca and P in the initial stages. Conclusion: From the results above, it can be considered that alkali and heat treated implants in the atmosphere have advantages in osseointegration in early stages and may decrease the time interval between implantation and functional adaptation.

• The Korean Journal of Air & Space Law and Policy
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• v.25 no.1
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• pp.27-54
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• 2010

Soon after September 11 attacks in 2001, there were strong demands in Korea on making relevant laws and regulations on aviation security, and Korean parliament legislated "Aviation Safety and Security Act"to fulfill the demands on safety and security of aircrafts during aviation. However, the current Aviation Safety and Security Act seems to have many problems which do not meet the practical needs in Korea, because there were not enough considerations on the practical needs and extinguishable national circumstances on civil aviation system in Korea, but only regarded the relevant international conventions and foreign practices on it. In this context, it is necessary to amend several provisions in Aviation Safety and Security Act to enhance more practical efficiencies in its implementation through systematization of the provisions on crimes which may happen during aviation. In this context, this article argues two main issues. First, Article 39 of Aviation Safety and Security Act does not express whether it is possible to punish the attempt of crime of causing damage to aircraft. Therefore, regarding a principle of legality, it is impossible to punish the perpetrator even when coincidently failed to destruct or damage aircraft. In this context, this article argues that the necessity to introduce the possibility to punish the attempt of crime of causing damage to aircraft. Second, regarding Article 160 of Civil Aviation Act of Korea, current Aviation Safety and Security Act should be amended by guaranteeing the culpability of negligence of crime of causing damage to aircraft.

• Journal of dental hygiene science
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• v.10 no.4
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• pp.219-225
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• 2010

The purpose of this study was to examine the patients' knowledge and expectation of dental implants and to provide effective consulting and accurate information on implants to them. To that end, between March 23, 2008 and June 5, 2008, patients who were visiting dental clinics (hospitals) in Seoul, Gyeonggi-do, and Incheon areas were surveyed. 84.7% of subjects said that they recognized implants, and the largest number of them (26.7%) of subjects came to know via friends. According to an analysis of subjects' knowledge of the dental implant operation, the maximum value was 4.06, and the minimum value was 3.05. The opinion value on the need to have regular examination after the implant operation was highest at 4.06. Regarding expectation over the implant operation, the maximum value was 4.42, and the minimum value was 1.78. The opinion value on considering the implant operation capability the most important was the highest at 4.42. The relationship between the knowledge of and expectation over implants was significant. By gender, females had a significantly higher level of knowledge than males. Regarding preference, females scored 3.27 points, and males scored 3.23 points. By occupation, professionals earned the highest score of 3.55 in knowledge, and professionals earned the highest score of 3.31 in expectation. According to an analysis of the relation between variables of knowledge of and variables of expectation over implants, the correlation coefficient (r) between the two factors was 0.362, indicating a positive relevancy(+)(p<.01).

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.1
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• pp.48-54
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• 2010

Purpose: The objective of this study was to evaluate and compare the accuracy of impression body taking by the closed and the open tray impression technique with 3 types of impression tray. Individual tray, metal stock tray and polycarbonate tray were used. Materials and methods: Nine closed tray impressions were taken by individual tray, metal stock tray and polycarbonate stock tray, respectively with polyether impression material. 9 open tray impressions were also acquired by same manner. Precision analysis on the master models was performed by attaching the reference frameworks with alternate single screws and measuring the vertical fit discrepancy of respective analogues in working cast with a stereo microscope. Data were analyzed by 1 way ANOVA and independent t-test. Results: The average fit accuracy of impression bodies was calculated. With the closed tray impression technique, there were significant statistical differences in vertical fit discrepancy according to the types of tray. The individual tray group showed the lowest value and the polycarbonate stock tray group represented the highest. With the open tray impression technique, there was no significant difference in vertical fit discrepancy. Significant statistical difference in vertical fit discrepancy was found between the open and the closed impression technique with the polycarbonate stock tray. Conclusion: From the results above, more precise impressions could be acquired by the rigid individual tray compared with the polycarbonate stock tray. It was hard to get consistent accuracy impressions by the closed tray impression technique with polycarbonate stock trays.

• Journal of the Korea Institute of Building Construction
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• v.9 no.4
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• pp.119-129
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• 2009

Building construction trends have been changed dramatically in terms of size and mass. With the need to maximize land usage, there has been an increase in the construction of high-rise buildings. This affects not only the entire construction duration and cost, but also subsequent construction activities, such as work to increase underground facilities and in reclamation land area construction. These types of site conditions require soft ground reinforcement and the proper uplift water pressure treatment. In general, two kinds of methods have been used for uplift water pressure treatment systems. However, there have been some problems arising as the result of a lack of research and analysis on underground construction techniques, and a reliance on experiments over actual survey and analysis of site conditions. This paper focused on the problems of conventional selection procedure, by analyzing drawings and proposing a kind of modeling for a reasonable procedure. The results were applied to OO project as a sample construction case to be verified in this research. The initial plan in the case project was the Rock Anchor System. However, as there were terrible miscalculations of basic site conditions that had an extraordinary influence on the underground water level, such as the site's proximity to the Han-river, it was necessary to change the plan to include apermanent drainage system. This achieved a direct construction cost reduction \ 406,702,000 and a maximum sayings of 4% of operational cost, based on the 50-year building Life Cycle Cost.

• Journal of Intelligence and Information Systems
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• v.16 no.3
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• pp.163-179
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• 2010

Recentlythe concept of fast fashion is drawing attention as customer needs are diversified and supply lead time is getting shorter in fashion industry. It is emphasized as one of the critical success factors in the fashion industry how quickly and efficiently to satisfy the customer needs as the competition has intensified. Because the fast fashion is inherently susceptible to trend, it is very important for fashion retailers to make quick decisions regarding items to launch, quantity based on demand prediction, and the time to respond. Also the planning decisions must be executed through the business processes of procurement, production, and logistics in real time. In order to adapt to this trend, the fashion industry urgently needs supports from intelligent quick response(QR) system. However, the traditional functions of QR systems have not been able to completely satisfy such demands of the fast fashion industry. This paper proposes an intelligent quick response system for the fast fashion(IQRS-FF). Presented are models for QR process, QR principles and execution, and QR quantity and timing computation. IQRS-FF models support the decision makers by providing useful information with automated and rule-based algorithms. If the predefined conditions of a rule are satisfied, the actions defined in the rule are automatically taken or informed to the decision makers. In IQRS-FF, QRdecisions are made in two stages: pre-season and in-season. In pre-season, firstly master demand prediction is performed based on the macro level analysis such as local and global economy, fashion trends and competitors. The prediction proceeds to the master production and procurement planning. Checking availability and delivery of materials for production, decision makers must make reservations or request procurements. For the outsourcing materials, they must check the availability and capacity of partners. By the master plans, the performance of the QR during the in-season is greatly enhanced and the decision to select the QR items is made fully considering the availability of materials in warehouse as well as partners' capacity. During in-season, the decision makers must find the right time to QR as the actual sales occur in stores. Then they are to decide items to QRbased not only on the qualitative criteria such as opinions from sales persons but also on the quantitative criteria such as sales volume, the recent sales trend, inventory level, the remaining period, the forecast for the remaining period, and competitors' performance. To calculate QR quantity in IQRS-FF, two calculation methods are designed: QR Index based calculation and attribute similarity based calculation using demographic cluster. In the early period of a new season, the attribute similarity based QR amount calculation is better used because there are not enough historical sales data. By analyzing sales trends of the categories or items that have similar attributes, QR quantity can be computed. On the other hand, in case of having enough information to analyze the sales trends or forecasting, the QR Index based calculation method can be used. Having defined the models for decision making for QR, we design KPIs(Key Performance Indicators) to test the reliability of the models in critical decision makings: the difference of sales volumebetween QR items and non-QR items; the accuracy rate of QR the lead-time spent on QR decision-making. To verify the effectiveness and practicality of the proposed models, a case study has been performed for a representative fashion company which recently developed and launched the IQRS-FF. The case study shows that the average sales rateof QR items increased by 15%, the differences in sales rate between QR items and non-QR items increased by 10%, the QR accuracy was 70%, the lead time for QR dramatically decreased from 120 hours to 8 hours.

• The Korean Journal of Nuclear Medicine
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• v.33 no.4
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• pp.368-380
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• 1999

Purpose: The purpose of this study was to evaluate and compare the scintigraphic findings and diagnostic accuracy of double-phase Tc-99m sestamibi scan in primary and secondary hyperparathyroidism (HPT). Materials and Methods: We retrospectively reviewed 16 cases of primary (18 lesions) and 11 cases of secondary HPT (44 lesions) who underwent Tc-99m-sestamibi scan before the surgical intervention. Scan was performed using LEM camera (Siemens, Germany) after the injection of 740MBq of Tc-99m sestamibi. Routine image consisted of baseline and 3-hour delayed images and each image was obtained using both parallel and pine hole collimator. The study population was 27 patients (male/female=5/22, age: $49.1{\pm}10.8$). Results: Eighteen lesions of primary HPT consisted of 13 adenomas and S hyperplasias, while all lesions of secondary HPT were hyperplasias. Among the case of primary HPT, we could detect all the lesions of 13 adenomas but only 2 lesions of 5 hyperplasias (40%) could be detected by double phase scintigraphy. Three cases of primary lesion showed decreased uptake in delayed images compared with baseline. The sensitivity, specificity, positive predictive value and accuracy of primary and secondary HPT were 58.8% (10/17), 83.3% (10/12), 83.3% (10/12), 75.9% (22/29), and 37.5% (15/40), 50% (2/4), 88.2% (15/17), 38.6% (17/44), respectively. Overall sensitivity, specificity, positive predictive value and accuracy were 43.9% (25/57), 75% (12/16), 86.2% (25/29), and 53.4% (39/73). There were no statistical difference between the weight of primary and secondary HPT lesion (p>0.05). Conclusion: Tc-99m sestamibi scan is fairly good modality to detect parathyroid lesion in patient with primary HPT before the surgical intervention. However, since some of cases may reveal decreased uptake in delayed image, a careful attention to the findings of baseline images may be helpful. Still the low accuracy of sestamibi scan in diagnosis of secondary HPT prohibits routine use of it for this disease.

• Journal of Distribution Science
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• v.8 no.1
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• pp.21-33
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• 2010

The ICT(information & communication technology) led to a dramatic change of floral distribution service, a phase of competition between wholesales and retail stores, and distribution channels in floral industry. It was expected that a role of the intermediaries in this industry would have reduced due to the improvement of transaction process by ICT. However, the ICT made to overcome a regional limit of the floral retail distribution service leading to an increase in sales and enlargement of the stores. And even it made possible to bring out another type of intermediaries such as private associations. This case study focuses on what kinds of efforts the floral wholesale distributors have made to enable a distribution process more smoothly between the wholesale distributors and retail stores through the information system, and what the failure factors in adopting the information system have been. This paper is also to examine how the wholesale distributors have changed themselves to gain dominant positions in distribution channels. As a result of the study, it was found that the intermediaries mostly failed in successfully achieving the distribution channel innovation through the information system because of several main reasons. FLOMARKET Inc. tried to innovate a distribution channel to obtain high quality goods through consolidating a wholesale distribution market in that segregated both floral joint market from free markets. after implementing the information system with consideration of the failure factors, FLOMARKET Inc. was able to minimize goods in stock and make a major purchase of various goods. In addition, it made a possible pre-ordering process and an exact calculation of purchasing goods so they could provide their products with market price in real time, which helped for the company to gain credits from their customers. Also, FLOMARKET Inc. established the information system which well suited to its business stage in order to deal with a rapidly changing distribution environment. It's so obvious that the transaction processing system of FLOMARKET Inc. definitely helped to share information among traders more seamlessly and smoothly in realtime, standardize goods, and make a transaction process clearer. Besides, the transaction information helped the wholesale distributors and retail stores to make more strategic decisions in their business because through the system they enabled to gather the marketing intelligence information more easily and convenient. If we understand that the floral distribution market is characterized by the low IT- based industry, it's worth to examine a case study proving that the information system actually increases the productivity of the transaction process in the floral industry.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.5
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• pp.15-29
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• 2021

This study is based on ERIS model for start-up performance, and aims to derive the main reason for start-up sustainability centered on organizational resilience. To this end, systematic literature examination and modified Delphi method were used to investigate start-up sustainability factors based on ERIS Model focused on organizational resilience. The results showed that ERIS model-based entrepreneurial continuity factors were divided into four categories: entrepreneur, resource, industrial environment, strategy, subdivision 8 and detailed factors 54. In addition, the ERIS model-based continuity factors were structured around organizational resilience, and the continuity factors were structured according to ERIS model under five categories: leadership, culture, people, system and environment. The results of this study are as follows. First of all, the results of existing research and analysis show that the concept of successful start-up and sustainability of start-up are used in various fields. Second, it is confirmed that there are common factors of influence on start-up performance and start-up sustainability based on ERIS model. Third, Delphi method's results showed that the general characteristics of entrepreneurs, such as academic background, education level, gender, age, and business experience did not affect the sustainability of entrepreneurship. This study is significant in that it is based on ERIS model focused on organization resilience, and ERIS-R, which integrates Strategy into System and Organization resilience into R in the field of gradually expanding start-up development and support. It is expected that the results of this study will improve the sustainability of start-up that can predict, prevent, and overcome various crises at any time.

• Journal of Korea Water Resources Association
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• v.53 no.12
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• pp.1159-1172
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• 2020

This study applied deep convolution neural network based on U-Net and SegNet using long period weather radar data to very short-term rainfall prediction. And the results were compared and evaluated with the translation model. For training and validation of deep neural network, Mt. Gwanak and Mt. Gwangdeoksan radar data were collected from 2010 to 2016 and converted to a gray-scale image file in an HDF5 format with a 1km spatial resolution. The deep neural network model was trained to predict precipitation after 10 minutes by using the four consecutive radar image data, and the recursive method of repeating forecasts was applied to carry out lead time 60 minutes with the pretrained deep neural network model. To evaluate the performance of deep neural network prediction model, 24 rain cases in 2017 were forecast for rainfall up to 60 minutes in advance. As a result of evaluating the predicted performance by calculating the mean absolute error (MAE) and critical success index (CSI) at the threshold of 0.1, 1, and 5 mm/hr, the deep neural network model showed better performance in the case of rainfall threshold of 0.1, 1 mm/hr in terms of MAE, and showed better performance than the translation model for lead time 50 minutes in terms of CSI. In particular, although the deep neural network prediction model performed generally better than the translation model for weak rainfall of 5 mm/hr or less, the deep neural network prediction model had limitations in predicting distinct precipitation characteristics of high intensity as a result of the evaluation of threshold of 5 mm/hr. The longer lead time, the spatial smoothness increase with lead time thereby reducing the accuracy of rainfall prediction The translation model turned out to be superior in predicting the exceedance of higher intensity thresholds (> 5 mm/hr) because it preserves distinct precipitation characteristics, but the rainfall position tends to shift incorrectly. This study are expected to be helpful for the improvement of radar rainfall prediction model using deep neural networks in the future. In addition, the massive weather radar data established in this study will be provided through open repositories for future use in subsequent studies.