• Structural Engineering and Mechanics
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• 제85권6호
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• pp.793-808
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• 2023

Türkiye is located in a region where destructive earthquakes are frequently experienced due to its geological characteristics and geographical location. Therefore, considering the possibility of a devastating earthquake at any time, determining the reinforced concrete (RC) building seismic safety, constructed before or after the current seismic buildings code, is one of the most important issues to be completed firstly. For this purpose, rapid assessment methods developed to quickly determine the seismic safety of buildings are available in the literature. Comparison of the principles of Principles of the Determination of Risky Structures-2019, Column and Wall Index Method, P25 Scoring Method and Improved Discriminant Analysis Method, which are among these methods, have been aimed within the scope of this study. Within the scope of this paper, a total of 43 buildings in the Yalova/Çınarcık region of Türkiye that the damage level was determined by street observation method immediately after the 1999 Kocaeli (Izmit) Earthquake; 15 buildings with heavy damage and 28 buildings with moderate damage were examined by rapid assessment methods. Although the risk detection difference was not separated as a clear line in any of the methods used, the results obtained from the rapid assessment methods are evaluated as being compatible with the detected after earthquake structural seismic behavior of the buildings. The PDRS-2019 and column and wall index method gave the most approximate results. In the results obtained from the analyzes; structural features such as number of floors, frame continuity, soft/weak story irregularity, effective shear strength area, existence of heavy overhangs in plan, type of structural system have been found to be significantly effective on the earthquake behavior of buildings.

• 스마트미디어저널
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• 제12권3호
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• pp.120-128
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• 2023

산업재해로 인한 피해를 줄이기 위해 다양한 ICT 기술이 지속적으로 개발되고 있으며, 센서, IoT, 빅데이터, 머신러닝 및 인공지능 등을 활용하여 산업재해 발생 시 피해를 최소화하고자 하는 연구가 진행되고 있다. 본 논문에서는 산업 현장의 밀폐구간, 산악, 해양, 탄광 등의 통신 음영지역에서 디바이스 간 다자간 통신 및 스마트 중계기와의 통신이 가능한 스마트 디바이스의 설계 방안을 제안한다. 제안된 스마트 디바이스는 작업자 위치, 이동 속도 등 작업자 정보와 지형, 풍향, 온도, 습도 등 환경정보를 수집하고 작업자 상호 간의 안전거리를 확보하여 위험 상황 발생 시 경고가 가능하며 헬멧에 부착할 수 있도록 설계하였다. 이를 위해, 스마트 디바이스에 필요한 기능적 요구사항과 스마트 디바이스 내의 센서와 모듈을 이용하여 요구사항을 구현하기 위한 설계 방안과 스마트 디바이스의 성능평가를 위한 지표를 도출하고 산악지역에서의 성능평가를 위한 평가환경을 제안한다.

• 대한의용생체공학회:의공학회지
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• 제44권2호
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• pp.147-156
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• 2023

Efforts to employ smart home sensors to monitor the indoor activities of elderly single residents have been made to assess the feasibility of a safe and healthy lifestyle. However, the bathroom remains an area of blind spot. In this study, we have developed and evaluated a new edge computer device that can automatically detect water usage activities in the bathroom and record the activity log on a cloud server. Three kinds of sound as flushing, showering, and washing using wash basin generated during water usage were recorded and cut into 1-second scenes. These sound clips were then converted into a 2-dimensional image using MEL-spectrogram. Sound data augmentation techniques were adopted to obtain better learning effect from smaller number of data sets. These techniques, some of which are applied in time domain and others in frequency domain, increased the number of training data set by 30 times. A deep learning model, called CRNN, combining Convolutional Neural Network and Recurrent Neural Network was employed. The edge device was implemented using Raspberry Pi 4 and was equipped with a condenser microphone and amplifier to run the pre-trained model in real-time. The detected activities were recorded as text-based activity logs on a Firebase server. Performance was evaluated in two bathrooms for the three water usage activities, resulting in an accuracy of 96.1% and 88.2%, and F1 Score of 96.1% and 87.8%, respectively. Most of the classification errors were observed in the water sound from washing. In conclusion, this system demonstrates the potential for use in recording the activities as a lifelog of elderly single residents to a cloud server over the long-term.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.174-174
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• 2023

The impact of global warming on the south Asian summer monsoon is of critical importance for the large population of this region. This study aims to investigate the future changes of the precipitation extremes during pre-monsoon and monsoon, across this region in a more organized regional structure. The study area is divided into six major divisions based on the Köppen-Geiger's climate structure and 10 sub-divisions considering the geographical locations. The future changes of extreme precipitation indices are analyzed for each zone separately using five indices from ETCCDI (Expert Team on Climate Change Detection and Indices); R10mm, Rx1day, Rx5day, R95pTOT and PRCPTOT. 10 global climate model (GCM) outputs from the latest CMIP6 under four combinations of SSP-RCP scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) are used. The GCMs are bias corrected using nonparametric quantile transformation based on the smoothing spline method. The future period is divided into near future (2031-2065) and far future (2066-2100) and then the changes are compared based on the historical period (1980-2014). The analysis is carried out separately for pre-monsoon (March, April, May) and monsoon (June, July, August, September). The methodology used to compare the changes is probability distribution functions (PDF). Kernel density estimation is used to plot the PDFs. For this study we did not use a multi-model ensemble output and the changes in each extreme precipitation index are analyzed GCM wise. From the results it can be observed that the performance of the GCMs vary depending on the sub-zone as well as on the precipitation index. Final conclusions are made by removing the poor performing GCMs and by analyzing the overall changes in the PDFs of the remaining GCMs.

• International journal of advanced smart convergence
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• 제12권3호
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• pp.1-12
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• 2023

A public address (PA) system installed in a building is a system that delivers alerts, announcements, instructions, etc. in an emergency or disaster situation. As for the products used in PA systems, with the development of information and communication technology, PA products with various functions have been introduced to the market. PA systems recently launched in the market may be connected through a single network to enable efficient management and operation, or use voice recognition technology to deliver quick information in case of an emergency. In addition, a system capable of locating a user inside a building using a location-based service and guiding or responding to a safe area in the event of an emergency is being launched on the market. However, the new PA systems currently on the market add some functions to the existing PA system configuration to make system operation more convenient, but they do not change the complex PA system configuration to reduce facility costs, maintenance, and management costs. In this paper, we propose a novel PA system configuration for buildings using audio networks and control hierarchy over peer-to-peer (Anchor) technology based on audio over IP (AoIP), which simplifies the complex PA system configuration and enables convenient operation and management. As a result of the study, through the emergency signal processing algorithm, fire broadcasting was made possible according to the detection of the existence of a fire signal in the Anchor system. In addition, the control device of the PA system was replaced with software to reduce the equipment installation cost, and the PA system configuration was simplified. In the future, it is expected that the PA system using Anchor technology will become the standard for PA facilities.

• 한국시뮬레이션학회논문지
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• 제19권3호
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• pp.1-6
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• 2010

MANET(Mobile Ad-hoc NETwork)은 실제 구현이나 동작과정에 많은 변수가 내재되어 있기 때문에 모델링 및 시뮬레이션 적용의 중요한 대상이 된다. MANET에서는 노드의 이동성으로 인해 다른 MANET과 중첩되거나 병합될 경우가 발생하며, 이 경우 다른 전달 방식을 가진 노드와의 통신을 위하여 새로운 경로 및 주소 설정이 선행되어야 한다. 이 과정은 새로 구성되는 네트워크에 있어서 오버헤드이기 때문에 이를 최소화하여 네트워크의 전달성능을 향상시킬 수 있도록 하기 위한 네트워크의 성능분석과 검증에 대한 연구가 필요하다. 본 논문에서는 오버헤드를 최소화할 수 있는 on-demand방식의 주소 자동설정 기법의 제안과, 제안한 기법의 타당성과 성능 검증을 위한 모델링 및 성능분석 내용을 제시하였다. NS-2에 의한 시뮬레이션은 기존의 방법에 비해 제안한 방법이 오버헤드를 줄이고 또한 시간적으로 분산되는 결과를 보였다.

• 대한조선학회논문집
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• 제60권1호
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• pp.31-37
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• 2023

In the present study, a method of performing cavitation erosion test directly on the anodized surface of the rudder model is proposed, not applying ink or paint on its surface. An image processing technique is newly developed to quantitatively evaluate the erosion damages on the rudder model surface after erosion test. The preprocessing saturation image, image smoothing, adaptive hysteresis thresholding and eroded area detection algorithms are in the image processing program. The rudder cavitation erosion tests are conducted in the rudder deflection angle range of 0° to -4°, which is used to maintain a straight course at the highest speed of the targeted navy ship. In the case of the conventional flat-type full-spade rudder currently being used in the target ship, surface erosion can occur on the model rudder surface in the above rudder deflection angle range. The bubble type of cavitation occurs on rudder surface, which is estimated to be the main reason of erosion damage on the rudder surface.

• Journal of Preventive Medicine and Public Health
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• 제56권1호
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• pp.41-49
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• 2023

Objectives: Rwanda reported a stunting rate of 33% in 2020, decreasing from 38% in 2015; however, stunting remains an issue. Globally, child deaths from malnutrition stand at 45%. The best options for the early detection and treatment of stunting should be made a community policy priority, and health services remain an issue. Hence, this research aimed to develop a model for predicting stunting in Rwandan children. Methods: The Rwanda Demographic and Health Survey 2019-2020 was used as secondary data. Stratified 10-fold cross-validation was used, and different machine learning classifiers were trained to predict stunting status. The prediction models were compared using different metrics, and the best model was chosen. Results: The best model was developed with the gradient boosting classifier algorithm, with a training accuracy of 80.49% based on the performance indicators of several models. Based on a confusion matrix, the test accuracy, sensitivity, specificity, and F1 were calculated, yielding the model's ability to classify stunting cases correctly at 79.33%, identify stunted children accurately at 72.51%, and categorize non-stunted children correctly at 94.49%, with an area under the curve of 0.89. The model found that the mother's height, television, the child's age, province, mother's education, birth weight, and childbirth size were the most important predictors of stunting status. Conclusions: Therefore, machine-learning techniques may be used in Rwanda to construct an accurate model that can detect the early stages of stunting and offer the best predictive attributes to help prevent and control stunting in under five Rwandan children.

• 환경생물
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• 제40권3호
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• pp.335-340
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• 2022

2017년 9월 부산 감만부두에서 국내 최초로 붉은불개미(Solenopsis invicta)가 검출된 이후, 농림축산검역본부에서는 외래개미류의 유입가능성이 높은 지역에 대해 주기적 예찰을 수행하고 있다. 그러나 현재 사용 중인 개미류 예찰용 트랩들은 개미가 들어갔다가 다시 쉽게 빠져나오거나, 토양이 없는 단단한 바닥 환경에서는 설치하기가 어려운 단점이 있다. 이를 해결하기 위해 다단협관을 이용하여 탈출이 어렵고, 콘크리트 같은 곳에서도 쉽게 설치가 가능한 신형 트랩을 개발하게 되었다. 신형 트랩은 함정트랩에 비해 4배 이상의 개미류 포획효과를 가지고 있으며, 포획된 개미들의 재탈출을 효과적으로 차단하는 것을 확인하였다. 새로 개발된 트랩을 통해 외래개미류의 국내 침입을 효과적으로 차단하기를 기대한다.

• 한국컴퓨터정보학회논문지
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• 제14권6호
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• pp.51-57
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• 2009

무선 센서 네트워크는 저가의 한정된 자원들을 갖는 수많은 센서 노드들로 구성된다. 보편적으로 대부분의 센서들은 안전하지 않거나 제어할 수 없는 환경에 배치되며, 만일 넓은 목표 지역에 센서 노드들을 무작위로 배치할 때에는 센서 노드들의 정확한 위치를 파악하기 매우 어렵다. 따라서 본 논문에서는 이러한 문제를 해결하기 위한 방안으로서 효율적인 키 분배 기법을 제안하고자 한다. 이에 제안된 기법을 통해 센서 노드들이 선-분배 된 키들을 사용하여 안전한 링크를 확립한 후 근접한 이웃 노드들과 서로 정보를 교환할 수 있도록 하였다. 또한 제안된 기법에서는 센서 노드의 위치 정보를 이용함으로써 노드 간에 공통키를 발견할 수 있는 확률을 높일 수 있게 하였다. 마지막으로 성능평가를 통해 우수함을 보이고자 한다.