• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.5C
• /
• pp.263-271
• /
• 2008

Investigation and analysis of the debris flow characteristics such as basin topography, geologic conditions of initiation location and triggering rainfall are required to systematically mitigate debris flow hazard. In this paper, 48 debris flows which had caused some damages to the highway in the past 5 years are investigated and their characteristics of basic topography and triggering rainfall are analyzed. Debris flows are found to occur in small basins having the area of $0.01{\sim}0.65km^2$ range and mostly initiated by the surficial failure of natural slope having the inclination of 29~55 degree during the intense rainfall. As for the triggering rainfall, rainfall of 2 to 5 year recurrence frequency are found to be able to trigger the debris flow and magnitude of debris flow in a basin could depend on the rainfall intensity and cumulative amount.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2019.11a
• /
• pp.268-268
• /
• 2019

The purpose of this study is to understand the risk of chemical product, Styrene Monomer(SM), shipped in a vessel. SM is harmful chemical product which can make injury, explosion and/or fire in a vessel. The understand of SM risk is very important to protect seafarer's body and vessel safety. This research can be expected that the understanding of SM risk by a seafarer's to prevent accidents by SM explosion and/or fire.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.4
• /
• pp.179-184
• /
• 2023

Korean society has experienced so-called 'societal crisis' in many aspects of society for a couple of decades and those crises include both natural disasters and tragic catastrophes. Given that, this study purports to investigate, first of all, what is the definition of crisis in general and societal crisis in specific. Next question is what are the major types of societal crises and what are the indicators for those crises. As a result, many areas of societal crisis and corresponding indicators in each area will be introduced. Finally, this study tries to establish a new definition of societal crises based upon a more sociological, more specifically a more phenomenological point of view. For these research purpose, in-depth review for previous research on the subject will be done including psychological and sociological materials. Final outcome of this study will be a new and experimental definition of societal crisis, which will provide the principle base for actual numeric indicators of societal crisis in both macro and micro level.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.45-45
• /
• 2022

산업화에 따른 화학물질 사용량의 증가는 담수로의 유해화학물질 유출사고의 위험을 증가시키며, 이러한 사고는 하천수 수질과 수환경 생태계에 심각한 위해와 손상을 야기한다. 이러한 수질사고 발생시 신속 대응을 위해, 하천에 유입된 물질의 거동을 신속하게 예측하는 것이 필요하며 이 경우 1차원 추적모형이 주로 사용된다. 1차원 물질혼합 모형은 하천을 하나의 유선으로 보며, 복잡한 하천흐름의 시스템을 현상학적으로 해석하고, 오염물질의 이송 및 혼합 메카니즘을 모델 매개변수에 반영하여 모형화한다. 이러한 매개변수들은 직접적으로 측정하기 어려우며, 이론에 기반한 매개변수 산정 기법이 구축되지 않은 실정이다. 따라서 대부분의 연구에서는 추적자 실험을 실시하여 유한한 하천구간에서 추적자의 시간-농도곡선(Breakthrough curve, BTC)을 취득하고, 이를 통하여 대상 구간의 매개변수를 역산하는 최적화 기법에 의존하고 있다. 하지만, 모든 하천구간에 대하여 추적자 실험을 수행하여 데이터를 확보하는 것이 어렵기 때문에 최적화 기법의 적용성에 한계가 있다. 본 연구는 흐름정보가 제공되지 않은 미계측 하천구간에서 BTC를 신속하게 예측할 수 있는 회귀모형을 구축하는 것을 목표로 한다. 국내 하천에서 수행한 4회의 추적자 실험으로부터 취득한 28개 구간 케이스의 데이터에 대하여 농도곡선 전처리를 수행하고 14개의 통계적 특징을 추출하였으며, 계측된 흐름특성과의 상관관계를 분석하였다. 분석 결과, 대상 구간에서의 BTC의 변화가 추적자의 유하거리에 매우 높은 상관관계를 보였으며, 이를 이용하여 회귀모형을 제시하였다. 제안된 회귀모형을 적용하여 하류의 지점에서의 BTC를 예측하였으며, 1차원 이송-분산 방정식과 하천저장대모형을 활용한 예측결과와 비교하여 검증하였다. 그 결과, BTC의 변화특성을 활용한 회귀적 예측이 하천 지형 및 흐름의 변동성이 작은 구간에서 1차원 혼합모형들을 이용한 예측보다 더 높은 정확도를 보였으며, 이러한 장점은 장거리 예측에서 더 분명하게 나타났다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.504-504
• /
• 2022

국내 금강유역의 경우 충남 서부와 북부지역을 중심으로 강수량 부족과 가뭄이 빈번히 발생하는 것으로 보고되며, '14년에도 강수량이 부족하였고, '15년에는 제한급수에 돌입하는 등 가뭄 피해가 최대 3년에 걸쳐 다년 발생하였다. 가뭄 발생 시 댐은 가뭄 대응단계별 용수공급조정기준에 따라 생공용수 여유량, 하천유지용수, 농업용수, 생공용수 순으로 감량 후 운영된다. 이중 하천유지용수는 수 생태계 및 하천과 관련이 있는 다양한 자연 자원의 보호와 보전을 위해 하천에 남아 흘러야 하는 물로 정의되며, 환경 및 생태계에 관한 중요성이 커짐에 따라 가뭄 시에도 하천이 유수의 정상적인 기능과 상태 유지를 위해 필요한 용수이다. 용수공급조정 기준은 지금까지 총 5차례 개정되었으며, 가장 최근인 '19년에는 가뭄 주의단계시 하천유지 용수 감량기준을 기존 하천유지용수 "100% 감량"에서 "최대 100% 감량"으로 개정되었다. 이를 통해 다양한 의사결정이 가능해졌지만, 한편으로는 구체적인 기준이 제시되지 않아 이해당사자 간 상호 협의를 통해 감량(주로 50%)하는 실정이다. 이러한 상호 협의의 과정은 다양한 이해당사자들의 의사를 반영할 수 있는 과정이긴 하지만 수자원의 부족은 직접적으로 주민들에게 심각한 피해로 이어지기에 보다 정교하고 합리적인 기준의 설정이 필요하다. 본 연구에서는 의사결정 과정에 활용할 수 있는 하천유지용수 최적 감량 방안을 제시한다. 본 연구에서 제시하는 방안은 각 이해당사자의 향후 체계적인 의사결정을 위해 근거를 제공하는 것이 목표이다. 이를 위해, 하천유지용수의 공급에 따른 편익과 가뭄 위험도 간의 관계를 규명하고, 관계에 따른 하천유지용수 감량 정도에 따른 피해를 추정한다.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.11 no.4
• /
• pp.501-508
• /
• 2023

Addressing urban noise problems, this study develops eco-friendly, inorganic sound-absorbing panels, overcoming the limitations of traditional PMMA and cement-based panels. These conventional panels pose safety risks due to flammability and environmental concerns due to carbon emissions. Utilizing industrial waste, the research comprises two phases: initial tests for physical and performance characteristics (fluidity, density, compressive strength, sound absorption) and subsequent development of optimized panel mixtures. This approach aims to replace existing panels with sustainable, effective alternatives, significantly contributing to safer, environmentally responsible urban infrastructure. The findings of this study have implications for the sound panel market, offering novel solutions for noise control while aligning with environmental and safety standards.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.33 no.5
• /
• pp.761-773
• /
• 2023

This paper proposes a method to increase the power-analysis resistance of the neural network model's feedforward process by replacing the exponential-based activation function, used in the deep-learning field, with an approximated function especially at the multi-layer perceptron model. Due to its nature, the feedforward process of neural networks calculates secret weight and bias, which already trained, so it has risk of exposure of internal information by side-channel attacks. However, various functions are used as the activation function in neural network, so it's difficult to apply conventional side-channel countermeasure techniques, such as masking, to activation function(especially, to exponential-based activation functions). Therefore, this paper shows that even if an exponential-based activation function is replaced with approximated function of simple form, there is no fatal performance degradation of the model, and than suggests a power-analysis resistant feedforward neural network with exponential-based activation function, by masking approximated function and whole network.

• Journal of Internet of Things and Convergence
• /
• v.9 no.6
• /
• pp.37-44
• /
• 2023

As a primary technology of Industry 4.0, human-robot collaboration (HRC) requires additional measures to ensure worker safety. Previous studies on avoiding collisions between collaborative robots and workers mainly detect collisions based on sensors and cameras attached to the robot. This method requires complex algorithms to continuously track robots, people, and objects and has the disadvantage of not being able to respond quickly to changes in the work environment. The present study was conducted to implement a web-based platform that manages collaborative robots by recognizing the emotions of workers - specifically their perception of danger - in the collaborative process. To this end, we developed a web-based application that collects and stores emotion-related brain waves via a wearable device; a deep-learning model that extracts and classifies the characteristics of neutral, positive, and negative emotions; and an Internet-of-things (IoT) interface program that controls motor operation according to classified emotions. We conducted a comparative analysis of our system's performance using a public open dataset and a dataset collected through actual measurement, achieving validation accuracies of 96.8% and 70.7%, respectively.

• Journal of Aerospace System Engineering
• /
• v.17 no.6
• /
• pp.118-126
• /
• 2023

Most of the aerospace industries establish the SAE AS9100 Quality Management System, and acquire commercial certification by the 3rd party. Nevertheless, they repeatably have to cope with similar quality system evaluation by the airworthiness authority for the production certificate, parts manufacturer approval, and technical standard order authorization in accordance with the applicable regulations. The current quality system evaluation criteria of the airworthiness authority could be recommended for reforms in order to reduce duplication and correspond to the industrial development and environmental changes. In this paper, we propose measures to reform the authority's evaluation criteria through comparative analysis among the IAQG SAE AS9100, the FAA quality system codes, and the MOLIT ACSEP requirements.

• Convergence Security Journal
• /
• v.23 no.3
• /
• pp.3-11
• /
• 2023

Zero Trust, characterized by the principle of "Never Trust, Always Verify," represents a novel security paradigm. The proliferation of remote work and the widespread use of cloud services have led to the establishment of Work From Anywhere (WFA) environments, where access to corporate systems is possible from any location. In such environments, the boundaries between internal and external networks have become increasingly ambiguous, rendering traditional perimeter security models inadequate to address the complex and diverse nature of cyber threats and attacks. This research paper introduces the implementation principles of Zero Trust and focuses on the Micro Segmentation approach, highlighting its relevance in mitigating the limitations of perimeter security. By leveraging the risk management framework provided by the National Institute of Standards and Technology (NIST), this paper proposes a comprehensive procedure for the adoption of Zero Trust. The aim is to empower organizations to enhance their security strategies.