• Title/Summary/Keyword: Computational infrastructure

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Sensitivity Analysis of Model Parameters used in a Coupled Dam-Break/FLO-2D Model to Simulate Flood Inundation (FLO-2D에서 댐붕괴 모형 매개변수의 침수 범위 민감도 분석)

  • Lee, Khil-Ha;Son, Myung-Ho;Kim, Sung-Wook;Yu, Soonyoung;Cho, Jin-Woo;Kim, Jin-Man;Jung, Jung-Kyu
    • The Journal of Engineering Geology
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    • v.24 no.1
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    • pp.53-67
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    • 2014
  • Numerical modeling is commonly used to reproduce the physical phenomena of dam-break and to compile resulting flood hazard maps. The accuracy of a dam-break model depends on the physical structure that describes the volume of storage, breach formation and progress, input variables, and model parameters. Model input and parameters are subjective in that they are prescribed; hence, caution is needed when interpreting the results. This study focuses on three parameters (breach degree ${\theta}$, shape factor P, and collapse rate k) used when the dam-break model is coupled with FLO-2D (a two-dimensional flood simulation model) to estimate flood coverage and depth etc. The results show that the simulation is sensitive to the shape factor P and the collapse rate k but not to the breach degree ${\theta}$. This study will contribute to reducing flood damage from dam-break disasters in the future.

Secure and Efficient Protocol for Vehicular Communication with Privacy Preservation (프라이버시를 보호하며 안전하고 효율적인 차량간 통신 프로토콜)

  • Kim, In-Hwan;Choi, Hyoung-Kee;Kim, Jung-Yoon
    • Journal of KIISE:Information Networking
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    • v.37 no.6
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    • pp.420-430
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    • 2010
  • Due to increasing demand for improving road safety and optimizing road traffic, Vehicular Ad-Hoc Networks (VANET) have been subject to extensive attentions from all aspects of commercial industry and academic community. Security and user privacy are fundamental issues for all possible promising applications in VANET. Most of the existing security proposals for secure VANET concentrate authentication with privacy preservation in vehicle-to-vehicle (V2V) and vehicle-to-roadside infrastructure (V2I) communications and require huge storage and network capacity for management of revocation list. Motivated by the fact, we propose a new scheme with security and privacy preservation which combines V2V and V2I communication. With our proposed scheme, the communication and computational delay for authentication and overhead for management of revocation list can be significantly reduced due to mutual authentication between a vehicle and a Roadside Unit (RSU) requires only two messages, and the RSU issues the anonymous certificate for the vehicle on behalf of the Trust Authority (TA). We demonstrate that the proposed protocol cannot only guarantee the requirements of security and privacy but can also provide efficiency of authentication and management of revocation list.

Trend of Research and Industry-Related Analysis in Data Quality Using Time Series Network Analysis (시계열 네트워크분석을 통한 데이터품질 연구경향 및 산업연관 분석)

  • Jang, Kyoung-Ae;Lee, Kwang-Suk;Kim, Woo-Je
    • KIPS Transactions on Software and Data Engineering
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    • v.5 no.6
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    • pp.295-306
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    • 2016
  • The purpose of this paper is both to analyze research trends and to predict industrial flows using the meta-data from the previous studies on data quality. There have been many attempts to analyze the research trends in various fields till lately. However, analysis of previous studies on data quality has produced poor results because of its vast scope and data. Therefore, in this paper, we used a text mining, social network analysis for time series network analysis to analyze the vast scope and data of data quality collected from a Web of Science index database of papers published in the international data quality-field journals for 10 years. The analysis results are as follows: Decreases in Mathematical & Computational Biology, Chemistry, Health Care Sciences & Services, Biochemistry & Molecular Biology, Biochemistry & Molecular Biology, and Medical Information Science. Increases, on the contrary, in Environmental Sciences, Water Resources, Geology, and Instruments & Instrumentation. In addition, the social network analysis results show that the subjects which have the high centrality are analysis, algorithm, and network, and also, image, model, sensor, and optimization are increasing subjects in the data quality field. Furthermore, the industrial connection analysis result on data quality shows that there is high correlation between technique, industry, health, infrastructure, and customer service. And it predicted that the Environmental Sciences, Biotechnology, and Health Industry will be continuously developed. This paper will be useful for people, not only who are in the data quality industry field, but also the researchers who analyze research patterns and find out the industry connection on data quality.

A Study on the Activation Plan for Early Childhood SW·AI Education Based on Actual Condition Survey of Kindergarten SW·AI Education (유치원 SW·AI 교육 실태조사를 기초로 한 유아 SW·AI 교육 활성화 방안에 관한 연구)

  • Pyun, Youngshin
    • Journal of Internet of Things and Convergence
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    • v.8 no.6
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    • pp.93-97
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    • 2022
  • The purpose of this study is to suggest implications for early childhood SW·AI education considering the characteristics of early childhood education through a survey on SW·AI education in kindergartens. For this study, data were collected from 194 kindergartens through convenience sampling. The data was analyzed using frequency distribution, and it was found that 44% of kindergartens are conducting SW·AI education. 22% are conducting SW·AI education in the form of regular curriculum, and 70% are conducting SW·AI education in the form of special activities after school. SW·AI education was found to be conducted mainly by external instructors (97%) in the classroom (80%). For SW·AI education, block coding-based programs developed by companies such as Naver and the Clova were used, and all of these programs used programs and teaching aids in a package format, including teaching aids and materials developed by companies. 56% answered that they are not currently conducting SW/AI education, and lack of awareness on SW·AI education and lack of human/environmental infrastructure were the main factors. In order to realize SW·AI education considering the characteristics of early childhood education based on this survey, First, SW·AI education programs should be developed to develop play-centered computational thinking skills. Second, systematic teacher education at the national level should be conducted. Finally, the establishment of a department dedicated to early childhood SW·AI consisting of early childhood education experts and SW·AI education experts and financial support at the national level should be provided.

Towards high-accuracy data modelling, uncertainty quantification and correlation analysis for SHM measurements during typhoon events using an improved most likely heteroscedastic Gaussian process

  • Qi-Ang Wang;Hao-Bo Wang;Zhan-Guo Ma;Yi-Qing Ni;Zhi-Jun Liu;Jian Jiang;Rui Sun;Hao-Wei Zhu
    • Smart Structures and Systems
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    • v.32 no.4
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    • pp.267-279
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    • 2023
  • Data modelling and interpretation for structural health monitoring (SHM) field data are critical for evaluating structural performance and quantifying the vulnerability of infrastructure systems. In order to improve the data modelling accuracy, and extend the application range from data regression analysis to out-of-sample forecasting analysis, an improved most likely heteroscedastic Gaussian process (iMLHGP) methodology is proposed in this study by the incorporation of the outof-sample forecasting algorithm. The proposed iMLHGP method overcomes this limitation of constant variance of Gaussian process (GP), and can be used for estimating non-stationary typhoon-induced response statistics with high volatility. The first attempt at performing data regression and forecasting analysis on structural responses using the proposed iMLHGP method has been presented by applying it to real-world filed SHM data from an instrumented cable-stay bridge during typhoon events. Uncertainty quantification and correlation analysis were also carried out to investigate the influence of typhoons on bridge strain data. Results show that the iMLHGP method has high accuracy in both regression and out-of-sample forecasting. The iMLHGP framework takes both data heteroscedasticity and accurate analytical processing of noise variance (replace with a point estimation on the most likely value) into account to avoid the intensive computational effort. According to uncertainty quantification and correlation analysis results, the uncertainties of strain measurements are affected by both traffic and wind speed. The overall change of bridge strain is affected by temperature, and the local fluctuation is greatly affected by wind speed in typhoon conditions.

Economic Impact of HEMOS-Cloud Services for M&S Support (M&S 지원을 위한 HEMOS-Cloud 서비스의 경제적 효과)

  • Jung, Dae Yong;Seo, Dong Woo;Hwang, Jae Soon;Park, Sung Uk;Kim, Myung Il
    • KIPS Transactions on Computer and Communication Systems
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    • v.10 no.10
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    • pp.261-268
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    • 2021
  • Cloud computing is a computing paradigm in which users can utilize computing resources in a pay-as-you-go manner. In a cloud system, resources can be dynamically scaled up and down to the user's on-demand so that the total cost of ownership can be reduced. The Modeling and Simulation (M&S) technology is a renowned simulation-based method to obtain engineering analysis and results through CAE software without actual experimental action. In general, M&S technology is utilized in Finite Element Analysis (FEA), Computational Fluid Dynamics (CFD), Multibody dynamics (MBD), and optimization fields. The work procedure through M&S is divided into pre-processing, analysis, and post-processing steps. The pre/post-processing are GPU-intensive job that consists of 3D modeling jobs via CAE software, whereas analysis is CPU or GPU intensive. Because a general-purpose desktop needs plenty of time to analyze complicated 3D models, CAE software requires a high-end CPU and GPU-based workstation that can work fluently. In other words, for executing M&S, it is absolutely required to utilize high-performance computing resources. To mitigate the cost issue from equipping such tremendous computing resources, we propose HEMOS-Cloud service, an integrated cloud and cluster computing environment. The HEMOS-Cloud service provides CAE software and computing resources to users who want to experience M&S in business sectors or academics. In this paper, the economic ripple effect of HEMOS-Cloud service was analyzed by using industry-related analysis. The estimated results of using the experts-guided coefficients are the production inducement effect of KRW 7.4 billion, the value-added effect of KRW 4.1 billion, and the employment-inducing effect of 50 persons per KRW 1 billion.

The Need and Improvement Direction of New Computer Media Classes in Landscape Architectural Education in University (대학 내 조경전공 교육과정에 있어 새로운 컴퓨터 미디어 수업의 필요와 개선방향)

  • Na, Sungjin
    • Journal of the Korean Institute of Landscape Architecture
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    • v.49 no.1
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    • pp.54-69
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    • 2021
  • In 2020, civilized society's overall lifestyle showed a distinct change from consumable analog media, such as paper, to digital media with the increased penetration of cloud computing, and from wired media to wireless media. Based on these social changes, this work examines whether the use of computer media in the field of landscape architecture is appropriately applied. This study will give directions for new computer media classes in landscape architectural education in the 4th Industrial Revolution era. Landscape architecture is a field that directly proposes the realization of a positive lifestyle and the creation of a living environment and is closely connected with social change. However, there is no clear evidence that landscape architectural education is making any visible change, while the digital infrastructure of the 4th Industrial Revolution, such as Artificial Intelligence (AI), Big Data, autonomous vehicles, cloud networks, and the Internet of Things, is changing the contemporary society in terms of technology, culture, and economy among other aspects. Therefore, it is necessary to review the current state of the use of computer technology and media in landscape architectural education, and also to examine the alternative direction of the curriculum for the new digital era. First, the basis for discussion was made by studying the trends of computational design in modern landscape architecture. Next, the changes and current status of computer media classes in domestic and overseas landscape education were analyzed based on prior research and curriculum. As a result, the number and the types of computer media classes increased significantly between the study in 1994 and the current situation in 2020 in the foreign landscape department, whereas there were no obvious changes in the domestic landscape department. This shows that the domestic landscape education is passively coping with the changes in the digital era. Lastly, based on the discussions, this study examined alternatives to the new curriculum that landscape architecture department should pursue in a new degital world.

A Study of Anomaly Detection for ICT Infrastructure using Conditional Multimodal Autoencoder (ICT 인프라 이상탐지를 위한 조건부 멀티모달 오토인코더에 관한 연구)

  • Shin, Byungjin;Lee, Jonghoon;Han, Sangjin;Park, Choong-Shik
    • Journal of Intelligence and Information Systems
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    • v.27 no.3
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    • pp.57-73
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    • 2021
  • Maintenance and prevention of failure through anomaly detection of ICT infrastructure is becoming important. System monitoring data is multidimensional time series data. When we deal with multidimensional time series data, we have difficulty in considering both characteristics of multidimensional data and characteristics of time series data. When dealing with multidimensional data, correlation between variables should be considered. Existing methods such as probability and linear base, distance base, etc. are degraded due to limitations called the curse of dimensions. In addition, time series data is preprocessed by applying sliding window technique and time series decomposition for self-correlation analysis. These techniques are the cause of increasing the dimension of data, so it is necessary to supplement them. The anomaly detection field is an old research field, and statistical methods and regression analysis were used in the early days. Currently, there are active studies to apply machine learning and artificial neural network technology to this field. Statistically based methods are difficult to apply when data is non-homogeneous, and do not detect local outliers well. The regression analysis method compares the predictive value and the actual value after learning the regression formula based on the parametric statistics and it detects abnormality. Anomaly detection using regression analysis has the disadvantage that the performance is lowered when the model is not solid and the noise or outliers of the data are included. There is a restriction that learning data with noise or outliers should be used. The autoencoder using artificial neural networks is learned to output as similar as possible to input data. It has many advantages compared to existing probability and linear model, cluster analysis, and map learning. It can be applied to data that does not satisfy probability distribution or linear assumption. In addition, it is possible to learn non-mapping without label data for teaching. However, there is a limitation of local outlier identification of multidimensional data in anomaly detection, and there is a problem that the dimension of data is greatly increased due to the characteristics of time series data. In this study, we propose a CMAE (Conditional Multimodal Autoencoder) that enhances the performance of anomaly detection by considering local outliers and time series characteristics. First, we applied Multimodal Autoencoder (MAE) to improve the limitations of local outlier identification of multidimensional data. Multimodals are commonly used to learn different types of inputs, such as voice and image. The different modal shares the bottleneck effect of Autoencoder and it learns correlation. In addition, CAE (Conditional Autoencoder) was used to learn the characteristics of time series data effectively without increasing the dimension of data. In general, conditional input mainly uses category variables, but in this study, time was used as a condition to learn periodicity. The CMAE model proposed in this paper was verified by comparing with the Unimodal Autoencoder (UAE) and Multi-modal Autoencoder (MAE). The restoration performance of Autoencoder for 41 variables was confirmed in the proposed model and the comparison model. The restoration performance is different by variables, and the restoration is normally well operated because the loss value is small for Memory, Disk, and Network modals in all three Autoencoder models. The process modal did not show a significant difference in all three models, and the CPU modal showed excellent performance in CMAE. ROC curve was prepared for the evaluation of anomaly detection performance in the proposed model and the comparison model, and AUC, accuracy, precision, recall, and F1-score were compared. In all indicators, the performance was shown in the order of CMAE, MAE, and AE. Especially, the reproduction rate was 0.9828 for CMAE, which can be confirmed to detect almost most of the abnormalities. The accuracy of the model was also improved and 87.12%, and the F1-score was 0.8883, which is considered to be suitable for anomaly detection. In practical aspect, the proposed model has an additional advantage in addition to performance improvement. The use of techniques such as time series decomposition and sliding windows has the disadvantage of managing unnecessary procedures; and their dimensional increase can cause a decrease in the computational speed in inference.The proposed model has characteristics that are easy to apply to practical tasks such as inference speed and model management.