• Steel and Composite Structures
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• v.16 no.4
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• pp.357-374
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• 2014

The design basis is being shifted from strength to deformation in modern performance-based design codes. This paper presents a practical method for optimization of eccentrically braced steel frames, based on the concept of uniform deformation theory (UDT). This is done by gradually shifting inefficient material from strong parts of the structure to the weak areas until a state of uniform deformation is achieved. In the first part of this paper, UDT is implemented on 3, 5 and 10 story eccentrically braced frames (EBF) subjected to 12 earthquake records representing the design spectrum of ASCE/SEI 7-10. Subsequently, the optimum strength-distribution patterns corresponding to these excitations are determined, and compared with four other loading patterns. Since the optimized frames have uniform distribution of deformation, they undergo less damage in comparison with code-based designed structures while having minimum structural weight. For further investigation, the 10 story EBF is redesigned using four different loading patterns and subjected to 12 earthquake excitations. Then a comparison is made between link rotations of each model and those belonging to the optimized one which revealed that the optimized EBF behaves generally better than those designed by other loading patterns. Finally, efficiency of each loading pattern is evaluated and the best one is determined.

• Journal of the Korean Society of Safety
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• v.15 no.2
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• pp.1-7
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• 2000

This paper presents the approach involving fault detection and diagnosis of gears using pattern recognition and Wavelet transform. It describes result of the comparison between KDI (Kullback Discrimination Information) with the nearest neighbor classification rule as one of pattern recognition methods and Wavelet transform to know a way to detect and diagnosis of gear damages experimentally. To model the damages 1) Normal (no defect), 2) one tooth is worn out, 3) All teeth faces are worn out 4) One tooth is broken. The vibration sensor was attached on the bearing housing. This produced the total time history data that is 20 pieces of each condition. We chose the standard data and measure distance between standard and tested data. In Wavelet transform analysis method, the time series data of magnitude in specified frequency (rotary and mesh frequency) were earned. As a result, the monitoring system using Wavelet transform method and KDI with nearest neighbor classification rule successfully detected and classified the damages from the experimental data.

• Journal of Oral Medicine and Pain
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• v.17 no.2
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• pp.129-149
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• 1992

In order to verify the acceleration effect of low level laser (LLL) on oral mucosal wound healing process at cell biological level, the author studied growth pattern and ultrastructure in human gingival fibroblasts flashed by GaAlAs LLL-830 nm, 15mW for 10 minutes/flash one to three times at interval of 3-4 days through the evaluation of cell growth rate, protein conent/cell, DNA content/cell and ultrastructural changes for 14 days. The results were as follows : 1. The growth rate in gingival fibloblasts treated by LLL showed 4 orderly stages-decreasing stage after LLL treatment, acute increasing stage 3 days after LLL treatment, restring stage and recovering stage. 2. The effect of multiple flashes on LLL at interval of 3 days more or less was not proportional to times of flash on acceleration of growth in gingival fibroblasts. 3. The total protein content per gingival fibroblast was not significantly changed by LLL treatment in comparison with control group. But some kinds of protein which might be cell growth promoting factors were decreased immediately after LLL treatment, thereafter were acutely increased in cellular protein profile. 4. In ultrastructural changes of gingival fibroblasts treated by LLL, more prominent rough endoplasmic reticulum, mitochondrial hyperplasia/hypertrophy and increased extracellular fibrillar matrix were observed in comparison with control group under same experimental period.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.2
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• pp.178-183
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• 2001

Welding is essential for the manufacture of a range of engineering components which may vary from very large structures such as ships and bridges to very complex structures such as aircraft engines, or miniature components for microelectronic applications. Especially, a domestic situation of the welding automation is still depend on the arc sensing system in comparison to the vision sensing system. Specially, the gap-detecting of workpiece using conventional arc sensor is proposed in this study. As a same principle, a welding current varies with the size of a welding gap. This study introduce to the fuzzy membership filter to cancel a high frequency noise of welding current, and ART2 which has the competitive learning network classifies the signal patterns the filtered welding signal. A welding current possesses a specific pattern according to the existence or the size of a welding gap. These specific patterns result in different classification in comparison with an occasion for no welding gap. The patterns in each case of 1mm, 2mm, 3mm and no welding gap are identified by the artificial neural network.

• Journal of Environmental Science International
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• v.4 no.4
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• pp.345-356
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• 1995

Examining the precipitation data collected during the period from 1960 to 1993, we found that Taegu Station represents an optimum station for explaining the interannual variations of the precipitation in Korea. Using the variations derived from Taegu, the secular trends of the precipitation in Korea have been studied. It was 삽so found that the interannual variations of summer monsoon precipitation are consistent with those of the annual precipitation. To explore the interannual variations of the summer monsoon precipitation, comparisons of the summer precipitation in Korea with that in China and Japan were made. The results of the empirical orthogonal function analysis showed that Korea, the Yangtze River and Huaihe River valley, and the south Japan are all located in the same climate system during summer. The detailed analysis was carried out on the comparison of the summer precipitation in Korea with that in the eastern part of the the mainland China. We found that the correlation pattern is similar to the East Asia/pacific pattern. The probable effects of the sea surface temperature on the precipitation in Korea were also discussed. Key Words : Precipitation in Korea, rainy seasons in East Asia, monsoon precipitation, interannual variations.

• International Journal of High-Rise Buildings
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• v.1 no.2
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• pp.87-97
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• 2012

The indoor environments in high-rise buildings are generally well enclosed by defined boundary conditions. Here, a numerical simulation method based on the Lattice Boltzmann method (LBM), which aims to model and simulate the turbulent flow accurately in an enclosed environment, and its comparison with traditional computational fluid dynamics (CFD) results, are presented in this paper. CFD has become a powerful tool for predicting and evaluating enclosed airflows with the rapid advance in computer capacity and speed, and various types of CFD turbulence modeling and its application and validation have been reported. The LBM is a relatively new method; it involves solving of the discrete Boltzmann equation to simulate the fluid flow with a collision model instead of solving Navier-Stokes equations. In this study, the LBM-based scheme of flow pattern and particle dispersion analyses are validated using the benchmark test case of two- and three-dimensional and isothermal conditions (IEA/Annex 20 case); the prediction accuracy and advantages are also discussed by comparison with the results of CFD.

• Ocean and Polar Research
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• v.23 no.2
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• pp.161-172
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• 2001

A model-to-model comparison is attempted between Princeton Ocean Model (POM) and Miami Isopycnic Coordinate Ocean Model (MICOM) as a first step to extend our knowledge of models' performances in studying the East Sea circulation. The two models have fundamentally different numerical schemes and boundary conditions imposed on these models are not exactly the same each other. This study indicates that MICOM has a critical weak point in that it does not reproduce the shallow surface currents properly while it handles the thermohaline processes and associated movements of intermediate and deep waters efficiently. It is suggested that the mixed layer scheme needs to be modified so that it can match with inflow boundary conditions in order to reproduce the surface currents properly in MICOM. POM reproduces the surface current pattern better than MICOM, although the surface currents in POM appear to undergo the unrealistic seasonal variation and have exaggeratedly large vertical scale. These defects seem to arise during the process of adapting POM to the East Sea, and removing these defects is left as a future task.

• Korean System Dynamics Review
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• v.12 no.4
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• pp.157-175
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• 2011

The purpose of this paper is to find out the effects of the gambler's fallacy bias on the supply chain. For this study, the simulation was based on a casual structure of the Beer Distribution Game from Sterman(2000)'s Business Dynamics and designed into 2 different models : the first model carries the exact same structure as the reference mentioned above and for the second model, the comparison model is used reflecting gambler's fallacy bias. Each model has 2 different demand patterns. The 4 cases of models was tested with 1,000 different random number seeds. The results for the simulation are following : In the aspect of the inventory and out of stock, the basic model resulted better than the comparison. However, in the bullwhip effect, the comparison model has less than the basic in terms of the level demand pattern. But there was no significant difference in the cycle demand.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.4
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• pp.903-910
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• 2016

As smart mobile devices having touchscreens are growingly deployed, a pattern lock system, which is one of the graphical password systems, has become a major authentication mechanism. However, a user's unlocking behaviour leaves smudges on a touchscreen and they are vulnerable to the so-called smudge attacks. Smudges can help an adversary guess a secret pattern correctly. Several advanced pattern lock systems, such as TinyLock, have been developed to resist the smudge attacks. In this paper, we study an automated smudge attack that employs machine learning techniques and its effectiveness in comparison to the human-only smudge attacks. We also compare Android pattern lock and TinyLock schemes in terms of security. Our study shows that the automated smudge attacks are significantly advanced to the human-only attacks with regard to a success ratio, and though the TinyLock system is more secure than the Android pattern lock system.

• Korean Journal of Oriental Medicine
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• v.16 no.2
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• pp.33-41
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• 2010

Patterns are symbolic expressions of life style or sentiment of people as a product of culture. Furthermore, it is a type of language that the shape or implication does not change much over time. Patterns shown on the Korean medical containers are related to human life and health that they are not very diverse and splendid but closed used in real life. The medical containers include the alcohol container or tea-ware in broad sense, but under this study, it would be handled only for the Korean medical containers directly used to protect human health and treatment of diseases. They would be the Medicine Mortar and Pestle that is used to grind the herbal medical ingredients, pots that hold the liquid decoction, containers to keep the medical ingredients in general conceptual use for medical purposes. The patterns inscribed are classified in animal pattern, plant pattern or alphabet pattern. Turtle, crane, ginseng, and life patterns have the contemplation to pray for long life without disease or good fortune, while plum pattern, dragon pattern and the like are used in the medical containers used mainly in royal families with the social status and dignity shown. As such, patterns have not only ornament elements but also the symbolic implication to represent long life without illness for human. It provides the basic data of medical wisdom contained in the pattern and willingness of human to protect life from illness. On the basis of such research, it would require ensuing studies to make comparison and analysis with the medical containers with the patterns in the adjacent countries in the days to come.