• Title/Summary/Keyword: ANN 기법

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ANN-Based Real-Time Damage Detection Technique Using Acceleration Signals in Beam-Type Structures (보 구조물의 가속도 신호를 이용한 인공신경망 기반 실시간 손상검색기법)

  • Park, Jae-Hyung;Lee, Yong-Hwan;Kim, Jeong-Tae
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.3
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    • pp.229-237
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    • 2007
  • In this study, an artificial neural network (ANN)-based damage detection algorithm using acceleration signals is developed for real-time alarming locations of damage in beam-type structures. A new ANN-algorithm using output-only acceleration responses is designed tot damage detection in real time. The cross-covariance of two acceleration-signals measured at two different locations is selected as the feature representing the structural condition. Neural networks are trained lot potential loading Patterns and damage scenarios of the target structure for which its actual loadings are unknown. The feasibility and practicality of the proposed method are evaluated from laboratory-model tests on free-free beams for which accelerations were measured before and after several damage cases.

Estimation of Rotational Stiffness of Connections in Steel Moment Frames by using Artificial Neural Network (인공신경망을 이용한 철골모멘트골조 접합부의 회전강성 손상예측)

  • Choi, Se-Woon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.1
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    • pp.107-114
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    • 2018
  • In this study, the damage detection method is proposed for the rotational stiffness of connections in steel moment frames by using artificial neural network(ANN). The flexural moment of columns, natural frequencies, modeshapes are used for the input layer in ANN while the damage index, that signify the damage level, is used for the output layer in ANN. The 5-story steel moment frame as an example structure is used to generate the train and test data. Total number of damage scenarios considered is 829. From the results of application, it is shown that the proposed method can accurately estimate the location and level of damages.

Traffic-Flow Forecasting using ARIMA, Neural Network and Judgment Adjustment (신경망, 시계열 분석 및 판단보정 기법을 이용한 교통량 예측)

  • Jang, Seok-Cheol;Seok, Sang-Mun;Lee, Ju-Sang;Lee, Sang-Uk;An, Byeong-Ha
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2005.05a
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    • pp.795-797
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    • 2005
  • During the past few years, various traffic-flow forecasting models, i.e. an ARIMA, an ANN, and so on, have been developed to predict more accurate traffic flow. However, these models analyze historical data in an attempt to predict future value of a variable of interest. They make use of the following basic strategy. Past data are analyzed in order to identify a pattern that can be used to describe them. Then this pattern is extrapolated, or extended, into the future in order to make forecasts. This strategy rests on the assumption that the pattern that has been identified will continue into the future. So ARIMA or ANN models with its traditional architecture cannot be expected to give good predictions unless this assumption is valid; The statistical models in particular, the time series models are deficient in the sense that they merely extrapolate past patterns in the data without reflecting the expected irregular and infrequent future events Also forecasting power of a single model is limited to its accurate. In this paper, we compared with an ANN model and ARIMA model and tried to combine an ARIMA model and ANN model for obtaining a better forecasting performance. In addition to combining two models, we also introduced judgmental adjustment technique. Our approach can improve the forecasting power in traffic flow. To validate our model, we have compared the performance with other models. Finally we prove that the proposed model, i.e. ARIMA + ANN + Judgmental Adjustment, is superior to the other model.

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Systolic Array Simulator Construction for the Back-propagation ANN (역전파 ANN의 시스톨릭 어레이를 위한 시뮬레이터 개발)

  • 박기현;전상윤
    • Journal of Korea Society of Industrial Information Systems
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    • v.5 no.3
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    • pp.117-124
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    • 2000
  • A systolic array is a parallel processing system which consists of processing elements of basic computation capabilities, connected with regular and local communication lines. It has been known that a systolic array is on of effective systems to solve complicated communication problems occurred between densely connected neurons on ANN(Artificial Neural Network). In this paper, a systolic array simulator for the back-propagation ANN, which automatically constructs the proper systolic array for a given number of neurons of the ANN, is designed and constructed. With animation techniques of the simulators, it is easy for users to be able to examine the execution of the back-propagation algorithm on the designed systolic array step by step. Moreover the simulator can perform forward and backward operations of the back-propagation algorithm either in sequence or in parallel on the designed systolic array. Parallel execution can be performed by feeding continuous input patterns and by executing bidirectional propagations on all of processing elements of a systolic array at the same time.

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Comparison of ANN model's prediction performance according to the level of data uncertainty in water distribution network (상수도관망 내 데이터 불확실성에 따른 절점 압력 예측 ANN 모델 수행 성능 비교)

  • Jang, Hyewoon;Jung, Donghwi;Jun, Sanghoon
    • Journal of Korea Water Resources Association
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    • v.55 no.spc1
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    • pp.1295-1303
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    • 2022
  • As the role of water distribution networks (WDNs) becomes more important, identifying abnormal events (e.g., pipe burst) rapidly and accurately is required. Since existing approaches such as field equipment-based detection methods have several limitations, model-based methods (e.g., machine learning based detection model) that identify abnormal events using hydraulic simulation models have been developed. However, no previous work has examined the impact of data uncertainties on the results. Thus, this study compares the effects of measurement error-induced pressure data uncertainty in WDNs. An artificial neural network (ANN) is used to predict nodal pressures and measurement errors are generated by using cumulative density function inverse sampling method that follows Gaussian distribution. Total of nine conditions (3 input datasets × 3 output datasets) are considered in the ANN model to investigate the impact of measurement error size on the prediction results. The results have shown that higher data uncertainty decreased ANN model's prediction accuracy. Also, the measurement error of output data had more impact on the model performance than input data that for a same measurement error size on the input and output data, the prediction accuracy was 72.25% and 38.61%, respectively. Thus, to increase ANN models prediction performance, reducing the magnitude of measurement errors of the output pressure node is considered to be more important than input node.

Tunnel Design/Construction Risk Assessment base on GIS-ANN (GIS-ANN 기반의 도심지 터널 설계/시공 위험도 평가)

  • Yoo, Chung Sik;Kim, Joo Mi;Kim, Sun Bin;Jung, Hye Young
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.1C
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    • pp.63-72
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    • 2006
  • Due to rapid development of many cities in Korea, many public facilities are required to be built as well as complementary civil structures. Consequently, a number of tunnel constructions are currently carried out throughout the country, and many more tunnels are planned to be constructed in the near future. Tunnel excavation in a city often causes serious damage to above-ground structures and sewer system because of unexpected settlement. In order to prevent the destruction, the tunnel, which bypasses the center of a city, must be specially evaluated for its influence to other structure. In addition, since a slight disturbance of above-ground structure causes numerous public complaints and civil appeals, it must be approached with different method than the mountain tunnels. In this paper, the evaluation method using the Artificial Neural Network (ANN) has been studied. The method begins with an analysis of the minimal sectional area. If its result can be used to approximate the general influence of the whole section, the actual evaluation using ANN will take off. In addition, it also studies the construction management method which reflects the real time soil behavior and environment influence during construction using Geographic Information System (GIS).

Intrusion Detection System Utilizing Stack Ensemble and Adjacent Netflow (스텍앙상블과 인접 넷플로우를 활용한 침입 탐지 시스템)

  • Ji-Hyun Sung;Kwon-Yong Lee;Sang-Won Lee;Min-Jae Seok;Se-Rin Kim;Harksu Cho
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.33 no.6
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    • pp.1033-1042
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    • 2023
  • This paper proposes a network intrusion detection system that identifies abnormal flows within the network. The majority of datasets commonly used in research lack time-series information, making it challenging to improve detection rates for attacks with fewer instances due to a scarcity of sample data. However, there is insufficient research regarding detection approaches. In this study, we build upon previous research by using the Artificial neural network(ANN) model and a stack ensemble technique in our approach. To address the aforementioned issues, we incorporate temporal information by leveraging adjacent flows and enhance the learning of samples from sparse attacks, thereby improving both the overall detection rate and the detection rate for sparse attacks.

Application of Support Vector Regression for Improving the Performance of the Emotion Prediction Model (감정예측모형의 성과개선을 위한 Support Vector Regression 응용)

  • Kim, Seongjin;Ryoo, Eunchung;Jung, Min Kyu;Kim, Jae Kyeong;Ahn, Hyunchul
    • Journal of Intelligence and Information Systems
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    • v.18 no.3
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    • pp.185-202
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    • 2012
  • .Since the value of information has been realized in the information society, the usage and collection of information has become important. A facial expression that contains thousands of information as an artistic painting can be described in thousands of words. Followed by the idea, there has recently been a number of attempts to provide customers and companies with an intelligent service, which enables the perception of human emotions through one's facial expressions. For example, MIT Media Lab, the leading organization in this research area, has developed the human emotion prediction model, and has applied their studies to the commercial business. In the academic area, a number of the conventional methods such as Multiple Regression Analysis (MRA) or Artificial Neural Networks (ANN) have been applied to predict human emotion in prior studies. However, MRA is generally criticized because of its low prediction accuracy. This is inevitable since MRA can only explain the linear relationship between the dependent variables and the independent variable. To mitigate the limitations of MRA, some studies like Jung and Kim (2012) have used ANN as the alternative, and they reported that ANN generated more accurate prediction than the statistical methods like MRA. However, it has also been criticized due to over fitting and the difficulty of the network design (e.g. setting the number of the layers and the number of the nodes in the hidden layers). Under this background, we propose a novel model using Support Vector Regression (SVR) in order to increase the prediction accuracy. SVR is an extensive version of Support Vector Machine (SVM) designated to solve the regression problems. The model produced by SVR only depends on a subset of the training data, because the cost function for building the model ignores any training data that is close (within a threshold ${\varepsilon}$) to the model prediction. Using SVR, we tried to build a model that can measure the level of arousal and valence from the facial features. To validate the usefulness of the proposed model, we collected the data of facial reactions when providing appropriate visual stimulating contents, and extracted the features from the data. Next, the steps of the preprocessing were taken to choose statistically significant variables. In total, 297 cases were used for the experiment. As the comparative models, we also applied MRA and ANN to the same data set. For SVR, we adopted '${\varepsilon}$-insensitive loss function', and 'grid search' technique to find the optimal values of the parameters like C, d, ${\sigma}^2$, and ${\varepsilon}$. In the case of ANN, we adopted a standard three-layer backpropagation network, which has a single hidden layer. The learning rate and momentum rate of ANN were set to 10%, and we used sigmoid function as the transfer function of hidden and output nodes. We performed the experiments repeatedly by varying the number of nodes in the hidden layer to n/2, n, 3n/2, and 2n, where n is the number of the input variables. The stopping condition for ANN was set to 50,000 learning events. And, we used MAE (Mean Absolute Error) as the measure for performance comparison. From the experiment, we found that SVR achieved the highest prediction accuracy for the hold-out data set compared to MRA and ANN. Regardless of the target variables (the level of arousal, or the level of positive / negative valence), SVR showed the best performance for the hold-out data set. ANN also outperformed MRA, however, it showed the considerably lower prediction accuracy than SVR for both target variables. The findings of our research are expected to be useful to the researchers or practitioners who are willing to build the models for recognizing human emotions.

Landslide Susceptibility Prediction using Evidential Belief Function, Weight of Evidence and Artificial Neural Network Models (Evidential Belief Function, Weight of Evidence 및 Artificial Neural Network 모델을 이용한 산사태 공간 취약성 예측 연구)

  • Lee, Saro;Oh, Hyun-Joo
    • Korean Journal of Remote Sensing
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    • v.35 no.2
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    • pp.299-316
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    • 2019
  • The purpose of this study was to analyze landslide susceptibility in the Pyeongchang area using Weight of Evidence (WOE) and Evidential Belief Function (EBF) as probability models and Artificial Neural Networks (ANN) as a machine learning model in a geographic information system (GIS). This study examined the widespread shallow landslides triggered by heavy rainfall during Typhoon Ewiniar in 2006, which caused serious property damage and significant loss of life. For the landslide susceptibility mapping, 3,955 landslide occurrences were detected using aerial photographs, and environmental spatial data such as terrain, geology, soil, forest, and land use were collected and constructed in a spatial database. Seventeen factors that could affect landsliding were extracted from the spatial database. All landslides were randomly separated into two datasets, a training set (50%) and validation set (50%), to establish and validate the EBF, WOE, and ANN models. According to the validation results of the area under the curve (AUC) method, the accuracy was 74.73%, 75.03%, and 70.87% for WOE, EBF, and ANN, respectively. The EBF model had the highest accuracy. However, all models had predictive accuracy exceeding 70%, the level that is effective for landslide susceptibility mapping. These models can be applied to predict landslide susceptibility in an area where landslides have not occurred previously based on the relationships between landslide and environmental factors. This susceptibility map can help reduce landslide risk, provide guidance for policy and land use development, and save time and expense for landslide hazard prevention. In the future, more generalized models should be developed by applying landslide susceptibility mapping in various areas.