• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.4
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• pp.379-386
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• 2012

The primary aim of this paper was to evaluate several probabilistic fatigue crack propagation models using the residual of a random variable, and to present the model fit for probabilistic fatigue behavior in Mg-Al-Zn alloys. The proposed probabilistic models are the probabilistic Paris-Erdogan model, probabilistic Walker model, probabilistic Forman model, and probabilistic modified Forman models. These models were prepared by applying a random variable to the empirical fatigue crack propagation models with these names. The best models for describing fatigue crack propagation behavior in Mg-Al-Zn alloys were generally the probabilistic Paris-Erdogan and probabilistic Walker models. The probabilistic Forman model was a good model only for a specimen with a thickness of 9.45 mm.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.24 no.1
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• pp.44-49
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• 1988

The paper presents the preliminary results of an esperimental study on crack growth under tension-tension fatigue loading. A purpose of the study is to find the effect of the specimen thickness on crack propagation behaviors. The thickness of the low catbon steel specimens the are used in the experiments are 5, 10, 15,20, and 25 mm. the type of specimen considering in the present study is compact tension specimen.Crack growth behaviors are obseved and measured by travelling microscope. From the study, the followings are found; 1. There is a certain specimen thickness that is the shortest farigue life. The fatigue life of 15mm specimen is the shorter then that of any other opecimen 2. The crack initiation of the thick specimen is slower than that of thin specimen. But the crack propagation rate is just the opposite. 3. The range which is the exponent, m of power law(paris) is 1.98-4.59. the thicker the spec-imen is, the higher the value of m is.

• Food Science and Preservation
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• v.15 no.4
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• pp.518-523
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• 2008

This study sought to prepare Doenjang with added Ulmi cortex, to improve functionality and flavor, while retaining the original Doenjang scent. Ulmi cortex powders were added during fermentation. The Ulmi cortex-containing Doenjang showed lower pH and less salinity than did the Doenjang prepared without Ulmi cortex. Sensory evaluation data showed that Doenjang with Ulmi cortex tasted sweeter, and less salty, and was preferred over Doenjang without Ulmi cortex. In the DPPH assay, Doenjang with Ulmi cortex showed much higher free-radical scavenging ability (IC50 of 29.16 g/mL)did Doenjang without Ulmi cortex(IC50 of 155.67 g/mL), indicating that Ulmi cortex Doenjang has higher antioxidant levels. Doenjang prepared with 1%(w/v) Ulmi cortex powder was best in terms of consumer preference and functionality.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.73-79
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• 2006

A major purpose of this study is to develop high modulus asphalt mixtures for perpetual asphalt pavements which can save maintenance cost by increasing the design and performance periods of the pavements. Various physical and mechanical laboratory tests are performed for the high modulus asphalt binder developed in this study. The test results show that the properties of the high modulus binder are similar to those of the French high modulus binders. In addition to the binder tests, various performance tests are conducted for the high modulus and conventional mixtures. The dynamic modulus test results indicate that the dynamic modulus values of the high modulus mixtures are higher than those of the conventional mixtures by 10~15% at $5^{\circ}C$, 20~25% at $15^{\circ}C$ and 100% at $30^{\circ}C$. It is observed from the performance tests that the high modulus mixtures yield better fatigue, rutting and moisture damage performance than the conventional mixtures.

• Journal of Korean Society of Steel Construction
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• v.29 no.1
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• pp.49-60
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• 2017

As well as the strength check, fatigue life check is also mainly required for designing mooring lines of the floating structures. In general, forces which induce dynamic structural response significantly affect to fatigue design of the mooring lines. So, waves are mainly considered as the governing loading for fatigue design of the mooring lines. In this study, characteristics of the fatigue damage of the mooring lines for submerged floating tunnels (SFT) under irregular waves are investigated. For this study time domain hydrodynamic analysis is used to obtain motion of the tunnel and tension and stresses of the mooring lines under the specific environmental conditions. Also, the Rainflow-counting method, the Palmgren-Miner's rule, and S-N curves for floating offshore structures presented by DNV recommendation is applied to calculate the fatigue damage due to the fluctuating stresses. Referring to the design plactice of the tendon pipes for TLP (tension-leg platform), which is very similar structural system to SFT, it is assumed that a 100 year return period wave attacks the SFT systems during 48 hours and the fatigue damages due to the environmental loading are calculated. Following the analysis sequence, the effects of the tunnel draft, spacing and initial inclination angle of the mooring lines on the fatigue damage under the specific environmental loadings are investigated.

• Journal of the Korea Society of Computer and Information
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• v.19 no.1
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• pp.9-21
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• 2014

In this paper, we propose the auto correction technique of photography composition by which the eye line is concentrated and the stable image of the structure can be obtained in case the general user takes a picture. Because the general user photographs in most case without background knowledge about the composition of the photo, the subject location is not appropriate and the unstable composition is contrasted with the stable composition of pictures which the experts take. Therefore, we provide not the method processing the image after photographing, but he method presenting automatically the stable composition when the general users take a photograph. The proposed method analyze the subject through Saliency Map, Image Segmentation, Edge Detection, etc. and outputs the subject at the location where the stable composition can be comprised along with the guideline of the Rule of Thirds. The experimental result shows that the good composition was presented to the user automatically.

• The Korean Journal of Malacology
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• v.24 no.1
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• pp.59-66
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• 2008

The ark shell, Scapharca broughtonii were collected from the Jinhae bay in Kyungnam, Korea from April 2006 to October 2007. To assess how much they have tolerance against hypoxia under the compound condition of temperature and salinity, survivorship, oxygen consumption rate and external features of Scapharca broughtonii were measured, The 7 days-$LC_{50}$ of dissolved oxygen (DO) for Scapharca broughtonii at $15^{\circ}C$-ordinary sea water and $26{\pm}1$ psu was 1.98mg/L (confidence limit: 1,45-2.39 mg/L) and 2.63mg/L (confidence limit: 1.76-3.37mg/L) respectively. Whereas 3 days-$LC_{50}$ at $25^{\circ}C$-ordinary sea water was 3.89mg/L (confidence limit: 3.36-4.55 mg/L) and 4 days-$LC_{50}$ at $25^{\circ}C-26{\pm}1$ psu was 3.74mg/L (confidence limit: 3.19-4,43 mg/L). Oxygen consumption rate with each experimental group was decreased during the period exposed to hypoxia. To recovery, they were replaced to ordinary and oxygen consumption rate was increased a little, but all died, The color of the umbo of shell in Scapharca broughtonii was changed dark during hypoxia. These data will provide important fundamental information for examining the causes of mass mortality of shellfish in the summer.

• Tunnel and Underground Space
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• v.22 no.2
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• pp.77-85
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• 2012

In a material, micro-cracks can be progressively occurred, propagated and finally lead to failure when it is subjected to cyclic or periodic loading less than its ultimate strength. This phenomenon, fatigue, is usually considered in a metal, alloy and structures under repeated loading conditions. In underground structures, a static creep behavior rather than a dynamic fatigue behavior is mostly considered. However, when compressed air is stored in a rock cavern, an inner pressure is periodically changed due to repeated in- and-out process of compressed air. Therefore mechanical properties of surrounding rock mass and an inner lining system under cyclic loading/unloading conditions should be investigated. In this study, considering an underground lined rock cavern for compressed air energy storage (CAES), the mechanical properties of a lining system, that is, concrete lining and plug under periodic loading/unloading conditions were characterized through cyclic bending tests and shear tests. From these tests, the stability of the plug was evaluated and the S-N line of the concrete lining was obtained.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.01a
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• pp.253-256
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• 2021

본 논문에서는 합성곱 신경망을 통해 학습된 DoF(피사계 심도, Depth of field) 네트워크 아키텍처를 이용하여 객체 인식, 시점 추적, 문자 인식, 비사실적 렌더링 등 다양한 애플리케이션에 적용할 수 있는 사후 필터링 기법에 대해 살펴본다. 일반적으로 영상은 포커싱과 아웃포커싱에 의해 사용자의 관심표현이 결정되며, 이를 이용하여 영상 내 중요도를 판단한다. 영상 내에는 수많은 콘텐츠들이 혼재되어 있기 때문에 사용자가 집중적으로 보고 있는 콘텐츠를 찾아내기 어렵다. 본 논문에서는 사용자가 흥미롭고 집중적으로 보고 있는 영역을 DoF 네트워크로 학습시키고, 이를 통해 이전 기법으로는 표현할 수 없었던 DoF 기반 객체 인식, 시점 추적, 문자 인식, 비사실적 렌더링을 효율적으로 표현해낸다.

• Korean Journal of Food Science and Technology
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• v.51 no.4
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• pp.316-323
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• 2019

It is difficult to analyze pymetrozine in citrus fruits using the hydromatrix method because of its low efficiency of purification and overlap of matrix and pymetrozine peaks. Liquid-liquid extraction can analyze pymetrozine in citrus fruits using dichloromethane. Since low pH interferes with the extraction of pymetrozine, the extracts of citrus fruits were maintained over pH 7.0 by adding borax buffer and 1 N NaOH in the improved method. According to the improved method, citrus fruits (such as lemon, lime, orange, tangerine, and grapefruit) were extracted and purified for HPLC-photo diode array analysis. The results of validation were as follows: $4.360{\mu}g/kg$ of limit of detection, $14.533{\mu}g/kg$ of limit of quantitation, and 0.007 mg/kg of method quantitative limit. Citrus fruits spiked with pymetrozine showed a recovery range from 71.8 to 83.7% and a coefficient of variation below 6%. Thus, the improved method can efficiently analyze pymetrozine in citrus fruits.