• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.1
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• pp.55-62
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• 2002

In this paper, several types of infiltration prevention devices that are currently in use have been studied through experimental investigation. Firstly, the types of infiltration prevention devices were defined through investigating actual conditions of refrigerated warehouse in operates. Based on this investigation results, measured change of temperature and figured out air change rates of the type of infiltration prevention devices by using scale down model. After that, found the amount of air change rate in order to estimate the load of air change easily in facility plan.

• Journal of Fisheries and Marine Sciences Education
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• v.23 no.4
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• pp.596-606
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• 2011

This article analyzed the process of concluding the Korea-Russia IUU Fishing Prevention Agreement as a model case for distant water fisheries governance. The research studied co-operations for fisheries between Korea and Russia, the current status of live crabs landed in Korea through IUU fishing and Russia's political position on the IUU issue. Also this article reviewed a series of processes executed to achieve the bilateral agreement to prevent IUU fishing, including researches, intergovernmental negotiations, institutional improvements, public hearings and presentations. There were many things closely linked together such as international FAO-IUU prevention efforts, Russia's IUU fishing issue, Korean importers of Russian live crabs, their local governments and Korean snow-crab gill-net fishermen. These issues were resolved through reasonable reconciliations. This article wants to contribute to be used as a reference for other similar IUU fisheries cases.

• International Journal of Computer Science & Network Security
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• v.23 no.5
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• pp.179-192
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• 2023

The widespread use of Cloud Computing, Internet of Things (IoT), and social media in the Information Communication Technology (ICT) field has resulted in continuous and unavoidable cyber-attacks on users and critical infrastructures worldwide. Traditional security measures such as firewalls and encryption systems are not effective in countering these sophisticated cyber-attacks. Therefore, Intrusion Detection and Prevention Systems (IDPS) are necessary to reduce the risk to an absolute minimum. Although IDPSs can detect various types of cyber-attacks with high accuracy, their performance is limited by a high false alarm rate. This study proposes a new technique called Fuzzy Logic - Objective Risk Analysis (FLORA) that can significantly reduce false positive alarm rates and maintain a high level of security against serious cyber-attacks. The FLORA model has a high fuzzy accuracy rate of 90.11% and can predict vulnerabilities with a high level of certainty. It also has a mechanism for monitoring and recording digital forensic evidence which can be used in legal prosecution proceedings in different jurisdictions.

• Computers and Concrete
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• v.32 no.6
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• pp.615-623
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• 2023

Crack detection is an essential method to ensure the safety of dam concrete structures. Low-quality crack images of dam concrete structures limit the application of neural network methods in crack detection. This research proposes a modified attentional mechanism model to reduce the disturbance caused by uneven light, shadow, and water spots in crack images. Also, the focal loss function solves the small ratio of crack information. The dataset collects from the network, laboratory and actual inspection dataset of dam concrete structures. This research proposes a novel method for crack detection of dam concrete structures based on the U-Net neural network, namely AF-UNet. A mutual comparison of OTSU, Canny, region growing, DeepLab V3+, SegFormer, U-Net, and AF-UNet (proposed) verified the detection accuracy. A binocular camera detects cracks in the experimental scene. The smallest measurement width of the system is 0.27 mm. The potential goal is to achieve real-time detection and localization of cracks in dam concrete structures.

• The Journal of the Korea Contents Association
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• v.19 no.8
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• pp.137-150
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• 2019

In this study, we investigated the joint effects of message framing (profit vs. loss) and source type (celeb vs. general) on the persuasive effectiveness of mass media campaign to prevent drunk driving. As a result of conducting an experimental study on 218 motorcycle drivers in Vietnam, the main effects of message framing were not significant, but the interaction effect with the type of information source consistently influenced the attitude toward the advertisement, the drunk driving prevention, and the behavior intention Specifically, it is more persuasive to send a message by a general model rather than an celebrity when the loss framing method is used while it is more persuasive to send a message by a celebrity model than a general model when the gain framing is used. This study therefore provided valuable information and practical implication to the National Traffic Safety Committee of Vietnam for establishing a campaign to prevent drunk driving. In addition, this research also has valuable theoretical implication because it examines the effect of drunk driving prevention campaign on the attitude toward not only advertisement and the drunk driving prevention but also the behavior intention.

• Journal of the Korean Geotechnical Society
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• v.16 no.3
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• pp.67-75
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• 2000

본 연구에서는 지반의 비등방성을 고려한 점탄소성 bounding surface 모델의 정확성을 검증하고 모델정수의 영향을 고찰하였다. 이를 위하여 모델을 컴퓨터 프로그래밍 하였으며 실내시험을 실시하였다. 실내시험으로는 표준압밀시험, 등방/비등방 압밀 삼축압축시험, 크리프 시험 등이 실시되었다. 연구결과, 컴퓨터 프로그램을 이용한 해석결과와 실내시험 결과는 잘 부합되었으며, 탄소성 모델정수의 영향은 크지 않았으나 점소성 모델정수의 영향은 해석결과에 큰 영향을 미치는 것으로 고찰되었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.475-478
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• 2015

The objective of this study is to apply a hybrid model for estimating solar radiation and investigate their accuracy. A hybrid model is wavelet-based support vector machines (WSVMs). Wavelet decomposition is employed to decompose the solar radiation time series into approximation and detail components. These decomposed time series are then used as inputs of support vector machines (SVMs) modules in the WSVMs model. Results obtained indicate that WSVMs can successfully be used for the estimation of daily global solar radiation at Champaign and Springfield stations in Illinois.

• Fire Science and Engineering
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• v.28 no.3
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• pp.20-28
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• 2014

Effect of radiation models on the suppression limits in counterflow $CH_4$/air diffusion flame was numerically investigated with fundamental experiments for the numerical validation. $N_2$ and $CO_2$ were considered as extinguishing agents. The differences in extinguishing concentration between OTM and SNB radiation models which have different accuracy levels were examined. As a result, there is no considerable difference in extinguishing concentration for the $N_2$ dilution as the radiation models with different accuracy levels were used. As the $CO_2$ having strong radiative effect was diluted in the low strain flames, however, the radiation model with high predictive accuracy such as SNB should be used. In particular, the $CO_2$ dilution in fuel stream leads to the significant difference in extinguishing concentration between OTM and SNB models. Therefore, it is necessary that the radiation model should be reasonably chosen with the consideration of numerical accuracy and computational time for the prediction of extinguishing concentration.

• Journal of the Korean Geotechnical Society
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• v.31 no.1
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• pp.15-24
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• 2015

This paper presents the results of a reduced-scale physical model investigation into the effect of drilling fluid with different mix designs for bore hole collapse prevention. The bore hole collapse prevention mechanism for the bentonite based drilling fluid was first discussed together with the effect of conditioning with different additives on engineering characteristics of bentonite based drilling fluid. Reduced-scale model tests were then carried out considering field procedures for cases with a decomposed granitic soil with 20% fines and a sand with various drilling fluids with different mix designs. The results indicated that the addition of polymer to the bentonite based drilling fluid decreases the amount of drilling fluid injected, the drilling fluid infiltration thickness and increases the final depth of excavation. Also revealed is that the effect of polymer on the performance of drilling fluid is more pronounced in the decomposed granite soil with 20% fines than the sand. Practical implications of the findings from this study are discussed in great detail.

• Geomechanics and Engineering
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• v.15 no.5
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• pp.1081-1089
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• 2018

The deformation and strength of brittle rocks are significantly influenced by the crack closure behavior. The relationship between the strength and deformation of rocks under uniaxial loading is the foundation for design and assessment of such scenarios. The concept of relative crack closure strain was proposed to describe the influence of the crack closure behavior on the deformation and strength of rocks. Considering the crack compaction effect, a new damage constitutive model was developed based on accumulated AE counts. First, a damage variable based on the accumulated AE counts was introduced, and the damage evolution equations for the four types of brittle rocks were then derived. Second, a compaction coefficient was proposed to describe the compaction degree and a correction factor was proposed to correct the error in the effective elastic modulus instead of the elastic modulus of the rock without new damage. Finally, the compaction coefficient and correction factor were used to modify the damage constitutive model obtained using the Lemaitre strain equivalence hypothesis. The fitted results of the models were then compared with the experimental data. The results showed that the uniaxial compressive strength and effective elastic modulus decrease with an increase in the relative crack closure strain. The values of the damage variables increase exponentially with strains. The modified damage constitutive equation can be used to more accurately describe the compressive deformation (particularly the compaction stage) of the four types of brittle rocks, with a coefficient of determination greater than 0.9.