• Structural Engineering and Mechanics
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• v.31 no.2
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• pp.181-210
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• 2009

This paper presents the theoretical developments of an exact finite strip for the buckling and initial post-buckling analyses of isotropic flat plates. The so-called exact finite strip is assumed to be simply supported out-of-plane at the loaded ends. The strip is developed based on the concept that it is effectively a plate. The present method, which is designated by the name Full-analytical Finite Strip Method in this paper, provides an efficient and extremely accurate buckling solution. In the development process, the Von-Karman's equilibrium equation is solved exactly to obtain the buckling loads and the corresponding form of out-of-plane buckling deflection modes. The investigation of thin flat plate buckling behavior is then extended to an initial post-buckling study with the assumption that the deflected form immediately after the buckling is the same as that obtained for the buckling. It is noted that in the present method, only one of the calculated out-of-plane buckling deflection modes, corresponding to the lowest buckling load, i.e., the first mode is used for the initial post-buckling study. Thus, the postbuckling study is effectively a single-term analysis, which is attempted by utilizing the so-called semi-energy method. In this method, the Von-Karman's compatibility equation governing the behavior of isotropic flat plates is used together with a consideration of the total strain energy of the plate. Through the solution of the compatibility equation, the in-plane displacement functions which are themselves related to the Airy stress function are developed in terms of the unknown coefficient in the assumed out-of-plane deflection function. These in-plane and out-of-plane deflected functions are then substituted in the total strain energy expressions and the theorem of minimum total potential energy is applied to solve for the unknown coefficient. The developed method is subsequently applied to analyze the initial postbuckling behavior of some representative thin flat plates for which the results are also obtained through the application of a semi-analytical finite strip method. Through the comparison of the results and the appropriate discussion, the knowledge of the level of capability of the developed method is significantly promoted.

• Geophysics and Geophysical Exploration
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• v.18 no.1
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• pp.31-34
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• 2015

A gravity meter has been used for exploring subsurface mineral resources and monitoring long-period events such as Earth tides. Recently, researchers found several other intriguing features that we could even detect large teleseismic earthquakes and monitor seismic ambient noise using gravimeters. The zero-length spring suspension technology gives the gPhone (Micro-g LaCoste) excellent low frequency sensitivity, which may have implications for investigating much longer-period natural events (e.g., Earth's hum, tsunami waves, etc.). In this study, we present preliminary results through temporary operation of the gPhone at Geumsan in South Korea for 9 months (Nov. 2008-Jul. 2009). The gPhone successfully recorded large teleseismic events and showed a clear seasonal variation of the Double frequency microseisms during its operation period.

• Geophysics and Geophysical Exploration
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• v.21 no.3
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• pp.198-206
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• 2018

In this preliminary study, dehydration of the subducting slab and behavior of the expelled water are numerically modeled using 2-dimensional model scheme. The hydrated minerals in the oceanic crust of the subducting slab experience dehydration by increases in temperature and pressure and expel their water into the overlying mantle wedge. Behavior of the expelled water is governed by both the corner flow in the mantle wedge and porous flow of the expelled water through the pores of the mantle minerals. The effects of convergence rate and age of the subducting slab as well as grain size of the minerals on the dehydration of the subducting slab and behavior of the expelled water are evaluated. The water solubility of the oceanic crust measured from the laboratory experiments is considered for modeling dehydration of the oceanic crust. The model calculations show most of the hydrated minerals in the oceanic crust is dehydrated by a depth of 100 km and the effects of the convergence rate and age of the subducting slab on the dehydration of the subducting slab and behavior of the expelled water are not significant. The larger grain size allows faster porous flow of the expelled water through the oceanic crust, mantle wedge and overlying continental crust and reduces the volume fraction of the expelled water there. The developed technique will be used for future studies on arc volcanism and has a potential implication for the other fields such as seismic tomographic study.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.3
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• pp.257-268
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• 2016

The functions of anti-oxidation and anti-inflammation were investigated with the crude 80% methanol extract, subfractions and henryin isolated from Isodon inflexus (Thunb.) Kudo (I. inflexus (Thunb.) Kudo). Antioxidative ability was evaluated by bioassays using 2, 2-diphenyl-1-1-picrydrazyl (DPPH) free radical scavenging activity, xanthine oxidase inhibition, and superoxide radical scavenging effects. Ethyl acetate and butanol fractions exhibited free radical scavenging activity on superoxide with $IC_{50}$ values of $0.9{\mu}g/mL$, $0.2{\mu}g/mL$, respectively, which were stronger activity than that of allopurinol ($2.2{\mu}g/mL$) as reference. For the inhibition of anti-inflammatory activity in RAW 264.7 cell, the ethyl acetate fraction showed strong inhibition activity NO production, and henryin isolated from its subfraction reduced the activity in a dose-dependent manner. Ethyl acetate fraction and henryin suppressed not only mRNA expression of iNOS and COX-2, but also the mRNA expression of pre-inflammatory cytokines such as, TNF-${\alpha}$, 1L-$1{\beta}$, IL-6, in a dose-dependent manner. These results suggested that ethyl acetate fraction of I. inflexus (Thunb.) Kudo has considerable potential as a cosmetics ingredient with an antioxidant and anti-inflammatory effects and henryin can be applied as an functional reference.

• Food Science and Preservation
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• v.14 no.6
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• pp.598-604
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• 2007

Process development and standardization are necessary in maintaining high hygienicquality of side dishes. Seasoned perilla leaves are a typical side dish needing process development. In this study the optimum condition for preparing seasoned perilla leaves was investigated experimentally. The best sensory quality was established by response surface methodology. The rinsing and washing method of preparing fresh perilla leaves was optimized to decontaminate the raw material and preserve the product in chilled storage. Washing and rising with 3% salt water reduced the aerobic bacterial count of perilla leaves to 0.55 (log CFU/g), while rinsing reduced the load from 8.08 to 4.27 (log CFU/g). The effect of rinsing method was maintained during subsequent storage of the prepared seasoned leaves at $10^{\circ}C$. There was no significant quality change in the product during chilled storage at $10^{\circ}C$. Soaking in 3% salt water for 1 min, followed by rinsing with tap water, contributed positively to the microbial quality, and is proposed as the optimal preparation method.

• Food Science and Preservation
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• v.18 no.4
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• pp.517-526
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• 2011

The physical properties of dough with different levels (2, 4, 6, and 8%) of bamboo leaf powder were inverstigated. The bamboo leaf powder had a moisture content of 5.15%, a crude protein content of 10.48%, a crude fat content of 5.21%, a crude fiber content of 22.74%, and a crude ash content of 17.63%. The following parameters showed significant differences with the increase in the amount of bamboo leaf powder added. The gelatinization degree measured by a rapid visco-analyzer increased with the increase in the powder amount added. In the values of the farinogram parameter for dough consistency, the elasticity of the dough increased with the increase in the powder amount added. The alveogram values showed a similar tendency as those of the farinogram in terms of elasticity, absorption rate, absorption time and stability. In the rheofermentometer analysis, the volume decreased with the increase in the powder amount added, but no significant difference was found at up to 4% powder amount addition, suggesting that the about 2% and up to 4% powder amount addition is moderate.

• Food Science and Preservation
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• v.21 no.4
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• pp.506-511
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• 2014

In Gyeongsangbuk-do seongju area, hundreds of tons of spoiled oriental melon are harvested annually. Therefore, ways to prevent such spoilage are needed. This study was conducted to investigate the quality characteristics of spoiled oriental melon juice after enzyme treatment for the production of oriental melon concentrate. The treatment of the oriental melon juice with three kinds of enzymes with variable concentrations showed the following results. PECE(1), which was compounded pectinase and cellulase at 0.01% (v/v), gave the melon a 0.16 brown color and 0.01 turbidity, and the highest L value of 97.00. The detected free sugar contents were fructose, glucose and sucrose, with the amount of sucrose the highest at roughly 4,000 mg%. The mixture of different enzyme treatments resulted in a 0.15 brown color and 0.01 turbidity at 60 minutes, and the L value was high at 97.25. The enzyme treatment temperatures of $50^{\circ}C$ and $60^{\circ}C$ yielded a low-level brown color and low turbidity, but the L values were high at $60^{\circ}C$ and $70^{\circ}C$. These results showed that 0.01% (v/v) mixing enzyme, i.e., pectinase and cellulose compounded at $60^{\circ}C$ for 60 min, must be used for the production of oriental melon concentrate.

• Food Science and Preservation
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• v.20 no.4
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• pp.488-494
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• 2013

The study was done in order to investigate the effects the red onion powder on the quality characteristics of the Korean steamed rice cake, Seolgiddok, with 3%, 6%, 9% and 12% of the red onion powder weight in control. The moisture content of the control with 0% red onion was 43.74% and it steadily decreased with the increase in powder (12%) resulting to the lowest at 37.02% for the cake. The springiness, adhesiveness and chewiness of the cake decreased according to the increase in powder content, while the hardness and cohesiveness increased together with the increase in powder content. The Hunter color value L in the chromaticity of the cake significantly decreased with the increase in powder content. The a value of the control was 2.18 and was redder with the increase in powder content, while the b value significantly increased together with the increase in powder content. The sensory characteristics of the cake such as color, flavor, taste and softness and chewiness increased along with increase in powder content. The overall taste was judged to be the best for the sample with the 9% added powder.

• Journal of The Korean Association of Information Education
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• v.23 no.6
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• pp.675-687
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• 2019

As interest in artificial intelligence increases, each university has been establishing a special graduate school with artificial intelligence major, and recently, the Korea government has established various support policies for artificial intelligence education. However, each university has a lot of difficulties because it has little experience in operating graduate education with the latest field of artificial intelligence and it is not easy to find experts. In this study, the response of graduate school students majoring in artificial intelligence was analyzed using IPA technique, and the direction of education of graduate school artificial intelligence major was searched. Among the 40 items surveyed by IPA, 12 items such as systematization of artificial intelligence curriculum, progress of class considering learning level, improvement of academic relations with guidance professors were extracted as items to be improved first. On the other hand, 8 items such as assistant capacity, and relationship with colleagues were overloaded, and twelve items such as instructor's lecture competency, appropriateness of educational contents, learner's artificial intelligence skills and knowledge, and attitude acquisition were to be maintained. In addition, eight items such as convergence education curriculum and diversity of education methods were all low in importance and performance. It is suggested that AI graduate school should be divided into two tracks(technical specialization, convergence expansion) by educational goal, and each track should be conducted by level-specific educational contents and methods suitable for student level. The curriculum should be elaborate and systematic to acquire AI knowledge, skills, and attitudes, and should have an individualized guidance system centered on excellent faculty members.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.181-190
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• 2019

The purpose of this study is to evaluate the operational efficiency of Chinese e-commerce companies and to present measures to improve efficiency. This paper selected 16 enterprises as the research objects, from the e-commerce demonstration enterprises of the Ministry of Commerce of China in 2017-2018, to conduct an empirical study on the operating efficiency of e-commerce enterprises. By using DEA method, we selected 3 input and 2 output indicators to measure the input-output efficiency of enterprises from input-oriented. Using different model in DEA, we calculated the technical efficiency, pure technical efficiency and scale efficiency, also efficiency based on the sample of 2018 and horizontal analysis from 2016 to 2018. The analysis showed that the overall efficiency of Chinese e-commerce companies was continuously improving, and that their business capabilities and business scale were also gradually improving. Through the calculation of efficiency, we evaluated the competitiveness of the e-commerce demonstration enterprises, and explored measures to improve their management efficiency. At the same time, it put forward some reasonable suggestions to adjust the scale, and enhance the competitive advantage.