• Advances in concrete construction
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• v.13 no.6
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• pp.471-479
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• 2022

In this paper, vibrational attributes of double-walled carbon nanotubes (CNTs) has been studied based upon nonlocal elastic shell theory. The implication of small scale is being perceived by establishing nonlocal Love shell model. The wave propagation approach has been operated to frame the governing equations as eigen value system. The comparison of local and nonlocal model has been overtly explored by means of scaling parameter. An appropriate selection of material properties and nonlocal parameter has been considered. The influence of changing mechanical parameter Young's modulus has been studied in detail. The dominance of end condition via nonlocal parameter is explained graphically. The results generated furnish the evidence regarding applicability of nonlocal shell model and also verified by earlier published literature.

• Journal of Intelligence and Information Systems
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• v.16 no.3
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• pp.77-97
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• 2010

Market timing is an investment strategy which is used for obtaining excessive return from financial market. In general, detection of market timing means determining when to buy and sell to get excess return from trading. In many market timing systems, trading rules have been used as an engine to generate signals for trade. On the other hand, some researchers proposed the rough set analysis as a proper tool for market timing because it does not generate a signal for trade when the pattern of the market is uncertain by using the control function. The data for the rough set analysis should be discretized of numeric value because the rough set only accepts categorical data for analysis. Discretization searches for proper "cuts" for numeric data that determine intervals. All values that lie within each interval are transformed into same value. In general, there are four methods for data discretization in rough set analysis including equal frequency scaling, expert's knowledge-based discretization, minimum entropy scaling, and na$\ddot{i}$ve and Boolean reasoning-based discretization. Equal frequency scaling fixes a number of intervals and examines the histogram of each variable, then determines cuts so that approximately the same number of samples fall into each of the intervals. Expert's knowledge-based discretization determines cuts according to knowledge of domain experts through literature review or interview with experts. Minimum entropy scaling implements the algorithm based on recursively partitioning the value set of each variable so that a local measure of entropy is optimized. Na$\ddot{i}$ve and Booleanreasoning-based discretization searches categorical values by using Na$\ddot{i}$ve scaling the data, then finds the optimized dicretization thresholds through Boolean reasoning. Although the rough set analysis is promising for market timing, there is little research on the impact of the various data discretization methods on performance from trading using the rough set analysis. In this study, we compare stock market timing models using rough set analysis with various data discretization methods. The research data used in this study are the KOSPI 200 from May 1996 to October 1998. KOSPI 200 is the underlying index of the KOSPI 200 futures which is the first derivative instrument in the Korean stock market. The KOSPI 200 is a market value weighted index which consists of 200 stocks selected by criteria on liquidity and their status in corresponding industry including manufacturing, construction, communication, electricity and gas, distribution and services, and financing. The total number of samples is 660 trading days. In addition, this study uses popular technical indicators as independent variables. The experimental results show that the most profitable method for the training sample is the na$\ddot{i}$ve and Boolean reasoning but the expert's knowledge-based discretization is the most profitable method for the validation sample. In addition, the expert's knowledge-based discretization produced robust performance for both of training and validation sample. We also compared rough set analysis and decision tree. This study experimented C4.5 for the comparison purpose. The results show that rough set analysis with expert's knowledge-based discretization produced more profitable rules than C4.5.

• Proceedings of the Korea Port Economic Association Conference
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• 2006.08a
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• pp.1-12
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• 2006

As national economies globalize, demand for intercontinental container shipping services is growing rapidly, providing a potential economic boon for the countries and communities that provide port services. On the promise of profits, many governments are investing heavily in port infrastructure, leading to a possible glut in port capacity, driving down prices for port services and eliminating profits as ports compete for business. Further, existing ports are making strategic investments to protect their market share, increasing the chance new ports will be overcapitalized and unprofitable. Governments and port researchers need a tool for understanding how local competition in their region will affect demand for port services at their location, and thus better assess the profitability of a prospective port. We propose to develop such a tool by extending our existing simulation model of global container traffic to incorporate demand-side shipper preferences and supply-side strategic responses by incumbent ports to changes in the global port network, including building new ports, scaling up existing ports, and unexpected port closures. We will estimate shipper preferences over routes, port attributes and port services based on US and international shipping data, and redesign the simulation model to maximize the shipper's revealed preference functions rather than simply minimize costs. As demand shifts, competing ports will adjust their pricing (short term) and infrastructure (long term) to remain competitive or defend market share, a reaction we will capture with a game theoretic model of local monopoly that will predict changes in port characteristics. The model's hypotheses will be tested in a controlled laboratory experiment tailored to local port competition in Asia, which will also serve to demonstrate the subtle game theoretic concepts of imperfect competition to a policy and industry audience. We will apply the simulation model to analyze changes in global container traffic in three scenarios: addition of a new large port in the US, extended closure of an existing large port in the US, and cooperative and competitive port infrastructure development among Korean partner countries in Asia.

• Journal of the Korean Society for Library and Information Science
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• v.50 no.3
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• pp.113-132
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• 2016

Positioning technique which has been widely used for making marketing strategy by analyzing customer's image also has been used for public and test-taker's image analysis about public facilities, entrepreneurs, universities. This study analyze image of library and Information science students who trying to find a job in library fields about diverse types of library and information centers by Positioning technique. As a result of Similarity cognition analysis by multidimensional Scaling and K-means clustering, it was found that students recognize that public, national, university, school library are similar, on the other hand, portal company and special library are different from those types. In the jobs, user service jobs and technical service jobs are recognized as separated clusters, and cultural program job is also recognized dissimilarly from those clusters. By the way, images about work satisfaction and stability of employment shows high in national library; high wage shows high in portal company; employee's growth potential shows high in special library; job importance shows high in reference service jobs; difficulty shows high in content's job. Anyway, in the workplace selection, almost students regard stability of employment as top priorities, accordingly they prefers public library at most. Such a preference concentration tendency is strongly appeared in local university students than in metropolitan area students as a result of Pearson's chi-square test.

• Journal of Periodontal and Implant Science
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• v.46 no.6
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• pp.382-395
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• 2016

Purpose: Alendronate has been proposed as a local and systemic drug treatment used as an adjunct to scaling and root planing (SRP) for the treatment of periodontitis. However, its effectiveness has yet to be conclusively established. The purpose of the present meta-analysis was to assess the effectiveness of SRP with alendronate on periodontitis compared to SRP alone. Methods: Five electronic databases were used by 2 independent reviewers to identify relevant articles from the earliest records up to September 2016. Randomized controlled trials (RCTs) comparing SRP with alendronate to SRP with placebo in the treatment of periodontitis were included. The outcome measures were changes in bone defect fill, probing depth (PD), and clinical attachment level (CAL) from baseline to 6 months. A fixed-effect or random-effect model was used to pool the extracted data, as appropriate. Mean differences (MDs) with 95% confidence intervals (CIs) were calculated. Heterogeneity was assessed using the Cochrane ${\chi}^2$ and $I^2$ tests. Results: After the selection process, 8 articles were included in the meta-analysis. Compared with SRP alone, the adjunctive mean benefits of locally delivered alendronate were 38.25% for bone defect fill increase (95% CI=33.05%-43.45%; P<0.001; $I^2=94.0%$), 2.29 mm for PD reduction (95% CI=2.07-2.52 mm; P<0.001; $I^2=0.0%$) and 1.92 mm for CAL gain (95% CI=1.55-2.30 mm; P<0.001; $I^2=66.0%$). In addition, systemically administered alendronate with SRP significantly reduced PD by 0.36 mm (95% CI=0.18-0.55 mm; P<0.001; $I^2=0.0%$) and increased CAL by 0.39 mm (95% CI=0.11-0.68 mm; P=0.006; $I^2=6.0%$). Conclusions: The collective evidence regarding the adjunctive use of alendronate locally and systemically with SRP indicates that the combined treatment can improve the efficacy of non-surgical periodontal therapy on increasing CAL and bone defect fill and reducing PD. However, precautions must be exercised in interpreting these results, and multicenter studies evaluating this specific application should be carried out.

• Journal of the Korean Geographical Society
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• v.51 no.3
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• pp.401-420
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• 2016

This study aims to investigate the changes in the occupational structure of employment in Korea during the last three decades, in which have transformed from industrialized economy to knowledge-based economy very rapidly as well as having experiences of both IMF and financial crisis. For this purpose, we analyze the trends occupational distribution and the socio-demographic characteristics of the occupational structure of employment since 1980. By applying correspondence analysis of Multidimensional Scaling(MDS) methods, we examine the inter-relationships between the employed persons by occupation and their characteristics such as gender, age group, educational attainment, industry, region. We found the occupational structure of Korea has been changed dramatically with the socio-economic transformations during the last four decades. In particular, the occupational (job) structure has been highered in general. However, it has also been dualized extremely into two groups, one is the specialized-skilled-white color jobs and the other is the simple-unskilled-blue color jobs. The results of this study could be utilized as the importation basis for the provision of labour supply and employment policy plan at the national level as well as at the local level.

• Journal of Environmental Impact Assessment
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• v.30 no.4
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• pp.237-246
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• 2021

The similarity of hourly PM₁₀ and PM_2.5 concentration profiles of the atmospheric monitoring stations in Gyeonggi-do was evaluated through the multilateral analysis between stations. The existing category for most stations in the regions shows relatively low Pearson correlation values of 0.68 and 0.7 for PM₁₀ and PM_2.5 on average respectively, and some monitoring stations revealed high relationships over 0.8 to other regions. Since the current regions are mainly categorized by cluster analysis based on the number of occurrence of high concentration events and geological factors, it is necessary to reclassify them by concentration characteristics for precise fine dust management. In accordance, multi-dimensional scaling being able to visualize could categorize the regions based on regional emission contribution rate and hourly fine dust concentration. As a result of the current analysis, PM₁₀ and PM_2.5 could be reclassified into five regions and fourregions, respectively.

• Journal of Conservation Science
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• v.32 no.3
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• pp.437-448
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• 2016

Studies on vulnerability of cultural heritage and adaptation strategy to worldwide climate change have been actively carried out in advanced countries since the late 20th century, and this established a valid research methodology and piled up climate and deterioration dataset in the field of climate change. Meanwhile, we still have tasks to acquire related scientific data despite referencing political researches in Korea. Applying Korean future climate to impact analysis, deterioration of Korean stone heritage is likely prospected to change into complexity in terms of physical, chemical and biological weathering that may bring impacts on conservation business and administrative field of cultural heritage. Further studies will ensure detailed implication of climate change impact on Korean stone heritage by means of down-scaling analysis of areas to local scale and dataset frequency to an hour. It is important to sort out capability and vulnerability of the stone heritage to future environment, and to make an adaption and prevention strategies.

• Journal of Periodontal and Implant Science
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• v.24 no.3
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• pp.493-502
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• 1994

The benefits in using controlled delivery approaches include improved pharmacokinetic response, greater ability to localize the drung adjacent to the disease, and more control of local concentration at a lower total dosage. The purpose of this study was to evaluate the efficacy and safety of Minocline strip on chronic marginal periodontitis. Minocline Strip was applied in the periodontal pocket of 94 patients with a clinically diagnosed as a chronic marginal periodontitis, 4 sites for each patients with a 5mm probing pocket depth were selected in split mouth design and were divided into two group, ie., placebo group ($C_1$, $C_2$) and experimental group ($E_1$, $E_2$). Supragingival scaling and oral hygiene instruction were performed 1 week before experiment. Minocline Strip was applied on day 0 and 7, weekly, Clinical and microbiological tests were performed on day 0, 7, 14, 28 and 42. The results were as follows ; 1. Minocline Strip showed significant improvement on Chronic Marginal Periodontitis in 77 patients (82.0%) and improvement rate was more than 66.7% of all investigational items. 2. Only 6 patients complained mild pruritis during the early therapy but not needed discontinuence of the therapy. 3. The availability of Minocline Strip was 72 patients (76.6%) synthetically evaluating efficacy and safety. In conclusion, Minocline Strip appears to be effective and safe for the treatment of Chronic Marginal Periodontitis.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.6
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• pp.88-100
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• 1998

In this paper, an algorithm for a real-time automatic fingerprint identification system is proposed. The fingerprint feature volume is extracted by considering distinct and local characteristics(such as intensity and image quality difference etc.) in fingerprint images, which makes the algorithm properly adaptive to various image acquisitionj methods. Also the matching technique is designed to be invariant on rotation, scaling and translation (RST) changes while being capable of real-time processing. And the classification of fingerprints is performed based on the ridge flow and the relations among singular points such as cores and deltas. The developed fingerprint identification algorithm has been applied to various sets of fingerprint images such as one from NIST(National Institute of Standards and Technology, USA), a pressed fingerprint database constructed according to Korean population distributions in sex, ages and jobs, and a set of rolled-than-scanned fingerprint images. The overall performance of the algorithm has been analyzed and evaluated to the false rejection ratio of 0.07% while holding the false acceptance ratio of 0%.