• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.11 no.2
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• pp.31-40
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• 2007

What is the "new paradigm"? It is impossible express it in one or two words, but if one had to; the closest might be the "holistic approach". The expression can be justified by the fact that the conclusions above lead to a greater intermixing of mathematics with engineering and natural sciences subjects, typically expressed in the form of examples of simplified real problems. They also lead to a greater intermixing of subjects within mathematics so that the courses should have less separation e.g. between symbolic and numerical mathematics. The conclusions also lead to the spreading the mathematics courses throughout all study years, not just the first two years. Of course, this should be done with great care in order to guarantee studies that are logically linked together. The new paradigm also means that the needs arising from industrial mathematics must be taken into account in the contents of engineering mathematics courses. Such topics are e.g. multivariate methods, statistics and use of mathematical software. What are we expected to gain from the paradigm shift? The primary benefit should be in obtaining more productive engineers equipped with a better degree of mathematical preparedness for engineering problems. But in addition, it should also promote more intensive use of applied mathematics and easier communication with professional mathematicians, often needed in complicated industrial problems.?Finally, it can be noted that the new paradigm is in harmony with the basic ideas of the CDIO (Conceive - Design - Implement - Operate) initiative for producing the next generation of engineers [1]. New ideas for engineering education can be found also in the homepage of SEFI (European Society for Engineering Education) [2].

• YAKHAK HOEJI
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• v.42 no.2
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• pp.144-148
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• 1998

One hundred and seventeen crude drugs were screened for DNA-binding activity in vitro. The DNA-methyl green assay is a useful biochemical screen for the detection or development of biologically active compounds which bind to DNA. This assay is based upon the fact that free methyl green undergoes rapid spontaneous molecular rearrangement to its colorless carbinol base so that the liberation of the dye from DNA by displacement can be followed spectrophotometrically as a decrease in absorbance at 65Onm. Seven methanolic extracts of crude drugs including Cinnamomi Cortex spissus, Coicis Semen, Coptidis Rhizoma, Perillae Semen, Plantaginis Semen, Polygalae Radix and Zanthoxyli Fructus showed less than 2,000${\mu}$g/ml as their $IC_{50}$ values. The active principles of Plantaginis Semen and Zanthoxyli Fructus were transferred into organic solvents, which showed the $IC_{50}$ values with 588 and 574${\mu}$g/ml, respectively. These fractions have been selected for isolation of biologically active constituents.

• Journal of Electrical Engineering and Technology
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• v.8 no.2
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• pp.354-358
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• 2013

This paper discusses the analysis of arc conductance in a gas circuit breaker (GCB) during current interruption process and the investigation method of the interruption capability. There are some limitations in the application of the computational fluid dynamics (CFD) for the implementation of an arc model around the current zero, despite the fact that it gives good results for the high-current phase arc. In this study, we improved the accuracy in the analysis of the interruption performance by attempting the method using CFD and a mathematical arc model. The arc conductance at 200 ns before current zero (G-200ns) is selected as the indicator to predict the current interruption of the Short Line Fault (SLF). Finally, the proposed method is verified by applying to the actual circuit breakers which have different interruption performances.

• Wind and Structures
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• v.18 no.1
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• pp.37-56
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• 2014

The evaluation of pressure fields acting on slender structures under wind loads is currently performed in experimental aerodynamic tests. For wind-sensitive structures, in fact, the knowledge of global and local wind actions is crucial for design purpose. This paper considers a particular slender structure under wind excitation, representative of most common high-rise buildings, whose experimental wind field on in-scale model was measured in the CRIACIV boundary-layer wind tunnel (University of Florence) for several angles of attack of the wind. It is shown that an efficient reduced model to represent structural response can be obtained by coupling the classical structural modal projection with the so called blowing modes projection, obtained by decomposing the covariance or power spectral density (PSD) wind tensors. In particular, the elaboration of experimental data shows that the first few blowing modes can effectively represent the wind-field when eigenvectors of the PSD tensor are used, while a significantly larger number of blowing modes is required when the covariance wind tensor is used to decompose the wind field.

• Journal of Ocean Engineering and Technology
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• v.15 no.1
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• pp.98-103
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• 2001

This paper is conducted to compare the seismic design standard of a bridge column such as the Korean Bridge Design Standard(KBDS), EC 8, NZS 3101 and ATC 32. The KBDS adopted the seismic design requirements in 1992. The earthquake magnitude in Korea is compared with those in the west coast of the USA. It may be said that the current seismic design requirements of the KBDS provides design results, that are too conservative especially for transverse reinforcement details and amounts in reinforced concrete columns. This fact usually creates construction problems in concrete casting, due to congestion of transverse reinforcement. Furthermore, the effective stiffness; $I_{eff}$ depends on both the axial load P/$A_gF_{ck}$ and the longitudinal reinforcement ratio $A_{st}/A_g, so it is the conservative to use the effective stiffness I$_{eff}$ than the gross section stiffness Ig. Seismic design for the transverse reinforcement content of the concrete column was analyzed and considered to have an extreme-fiber compression strain, response modification factor, axial load and effective stiffness etc.c.

• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.13-16
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• 2011

The occurrence of major pest infestation was compared between conventional tea plantation and organic tea plantation at Sulloc tea garden in Dosun-dong, Seogwipo-si, Jeju-do from 2002 to 2009. Tetranychus kanzawai was observed a lot in the second year, but it waned from late June. There was not much difference between conventional farming and organic farming in terms of pest density. Empoasca onukii was infested in the second year of organic farming compared with conventional farming, which highlighted the fact that second year of organic farming requires a special care. Scirotothrips dorsalis was highly dense in the second and third year of conventional farming, but its occurrence was lowered when the farming technique was shifted to organic farming. The number of Homona magnanima peaked 4 times each year. In 2008, the first year of organic farming, saw high occurrence of 771.2 per trap per year. In 2009, the second year, the population per trap dropped to 80, showing a great variance depending on year. The occurrence of Caloptilia theivora peaked 5 times annually. In 2008, the first year of organic farming, an average of 2,779 pests per trap was found, and in the following year, 4,143 pests were observed. It showed that density rose in organic growing period.

• Advances in aircraft and spacecraft science
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• v.5 no.3
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• pp.349-362
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• 2018

A non-linear numerical simulation technique for predicting the unsteady performances of an airbreathing engine is developed. The study focuses on the simulation of integrated propulsion systems, where a closer coupling is needed between the airframe and the engine dynamics. In fact, the solution of the fully unsteady flow governing equations, rather than a lumped volume gas dynamics discretization, is essential for modeling the coupling between aero-servoelastic modes and engine dynamics in highly integrated propulsion systems. This consideration holds for any propulsion system when a full separation between the fluid dynamic time-scale and engine transient cannot be appreciated, as in the case of flow instabilities (e.g., rotating stall, surge, inlet unstart), or in case of sudden external perturbations (e.g., gas ingestion). Simulations of the coupling between external and internal flow are performed. The flow around the nacelle and inside the engine ducts (i.e., air intakes, nozzles) is solved by CFD computations, whereas the flow evolution through compressor and turbine bladings is simulated by actuator disks. Shaft work balance and rotor dynamics are deduced from the estimated torque on each turbine/compressor blade row.

• Environmental Engineering Research
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• v.24 no.1
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• pp.144-149
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• 2019

Landfill leachate constitutes one of the most polluting wastewaters. Their treatment was considered difficult due to the presence of high concentration of organic matter, ammonia, toxic organic compounds and heavy metals. Biological processes were found to be effective in several cases, but they are limited by the presence of inhibitory compounds in leachate. In this study we develop a biological process for the leachate biodetoxification using Trametes trogii (T. trogii; CLBE55). Results show that laccase activity, mycelia growth and chemical oxygen demand (COD) removal efficiencies varied depending on the leachate and ammonium concentration. Indeed T. trogii was able to grow in the presence of low concentration of landfill leachate of 10 and 30%. In fact, the biomass produced was 4.7 and 3.7 g/L, respectively leading to a COD removal of 66 and 53%, respectively. However, when the concentration of the introduced leachate exceeds 30%, the treatment efficiency and particularly the COD removal decreases to reach 15% at 100% leachate. The effect of the ammonia was also studied and results showed that the addition of 5 g/L of ammonia inhibited totally the production of laccase and the COD removal.

• Journal of Information Processing Systems
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• v.18 no.2
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• pp.245-257
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• 2022

In the Internet of Things (IoT) era, the types of devices used by one user are becoming more diverse and the number of devices is also increasing. However, a forensic investigator is restricted to exploit or collect all the user's devices; there are legal issues (e.g., privacy, jurisdiction) and technical issues (e.g., computing resources, the increase in storage capacity). Therefore, in the digital forensics field, it has been a challenge to acquire information that remains on the devices that could not be collected, by analyzing the seized devices. In this study, we focus on the fact that multiple devices share data through account synchronization of the online platform. We propose a novel way of identifying the user's interest through analyzing the remnants of targeted advertising which is provided based on the visited websites or search terms of logged-in users. We introduce a detailed methodology to pick out the targeted advertising from cache data and infer the user's interest using deep learning. In this process, an improved learning model considering the unique characteristics of advertisement is implemented. The experimental result demonstrates that the proposed method can effectively identify the user interest even though only one device is examined.

• Journal of the Korean Vacuum Society
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• v.6 no.S1
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• pp.122-126
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• 1997

the Cu/polyimide system is known to be the best candidate for a multilevel interconnection system due to the low resistance of Cu and to the low dielectric constant of polyimide respectively. Ion beam mixing of Cu(40nm)/polyimide was carried out at room temperature with 80 keV Ar+ and N2+ form $1.5\times$1015 to 15$\times$1015 ions/cm2. The quantitative adhesion strength was measured by a standard scratch test. X-ray photoelectron spectroscopy and x-ray emission spectrocopy are employed to investigate the chemical bonds and the interlayer compound formation of the films Cu/Al/polyimide showed more adhesion strength than Cu/polyimide after ion beam mixing and N2+ ions are more effective in the adhesion enhancement than Ar+ with the same sample geometry. The XES results shows the formation of interlayer compound of CuAl2O4 which can reflect more adhesive Cu/Al/polyimide which has not been reported previously. The latter results is understood by the fact that N2+ ions produce more pyridinelike moiety, amide group and tertiary amine moiety whcih are known as adhesion promotors.