• Title/Summary/Keyword: cloud data center

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Analysis of Summer Rainfall Case over Southern Coast Using MRR and PARSIVEL Disdrometer Measurements in 2012 (연직강우레이더와 광학우적계 관측자료를 이용한 2012년 여름철 남해안 강우사례 분석)

  • Moon, Ji-Young;Kim, Dong-Kyun;Kim, Yeon-Hee;Ha, Jong-Chul;Chung, Kwan-Young
    • Atmosphere
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    • v.23 no.3
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    • pp.265-273
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    • 2013
  • To investigate properties of cloud and rainfall occurred at Boseong on 10 July 2012, Raindrop Size distributions (RSDs) and other parameters were analyzed using observation data collected by Micro Rain Radar (MRR) and PARticle SIze and VELocity (PARSIVEL) disdrometer located in the National center for intensive observation of severe weather at Boseong in the southwest of the Korean peninsula. In addition, time series of RSD parameters, relationship between reflectivity-rain rate, and vertical variation of rain rates-fall velocities below melting layer were examined. As a result, good agreements were found in the reflectivity-rain rate time series as well as their power relationships between MRR and PARSIVEL disdrometer. The rain rate was proportional to reflectivity, mean diameter, and inversely proportional to shape (${\mu}$), slope (${\Lambda}$), intercept ($N_0$) parameter of RSD. In comparison of the RSD, as rain rate was increased, the slope of RSD became less steep and the mean diameter became larger. Also, it was verified that reflectivities are classified in three categories (Category 1: Z (reflectivity) > 40 dBZ, Category 2: 30 dBZ < Z < 40 dBZ, Category 3: Z < 30 dBZ). As reflectivity was increased, rain rate was intensified and larger raindrops were existed, while reflectivity was decreased, shape (${\mu}$), slope (${\Lambda}$), intercept ($N_0$) parameter of RSD were increased. We expected that these results will lead to better understanding of microphysical process in convective rainfall system occurred during short-term period over Korean peninsula.

User Targerting SaaS Application Mash-Up Service Framework using Complex-Context and Rule-Martix (복합 콘텍스트 및 Rule-Matrix를 활용한 사용자 맞춤형 SaaS 어플리케이션 연동 서비스 프레임워크)

  • Jung, Jong Jin;Cui, Yun;Kwon, Kyung Min;Lee, Han Ku
    • Journal of Korea Multimedia Society
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    • v.20 no.7
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    • pp.1054-1064
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    • 2017
  • With the development of cloud computing, internet technology and Internet of Things(IoT), most of applications are being smarter and changing from native application to SaaS (Software as a Service) application. New versatile SaaS applications are being released through various app portals (e.g. appstore, googleplay, T-Store, and so on). However, a user has a difficulty in searching, choosing an suitable application to him. It is also hard for him to know what functions of each SaaS application are useful. He wants to be recommended something inter-operated SaaS service according to his personality and his situation. Therefore, this paper presents a way of making mash-up of SaaS applications in order to provide the most convenient inter-operated SaaS service to user. This paper also presents SaaS Application Mash-up Framework (SAMF), complex context and rule matrix. The proposed SAMF is a main system that totally manage SaaS application mash-up service. Complex context and rule matrix are key components in order to recommend what SaaS applications are needed and how those SaaS applications are inter-operated. The SAMF collects complex contexts (User Description, Status Description, SaaS Service Description) in order to choose which SaaS applications are useful, analyze what functions to use, how to mash-up.

Design and Implementation of eBPF-based Virtual TAP for Inter-VM Traffic Monitoring (가상 네트워크 트래픽 모니터링을 위한 eBPF 기반 Virtual TAP 설계 및 구현)

  • Hong, Jibum;Jeong, Seyeon;Yoo, Jae-Hyung;Hong, James Won-Ki
    • KNOM Review
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    • v.21 no.2
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    • pp.26-34
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    • 2018
  • With the proliferation of cloud computing and services, the internet traffic and the demand for better quality of service are increasing. For this reason, server virtualization and network virtualization technology, which uses the resources of internal servers in the data center more efficiently, is receiving increased attention. However, the existing hardware Test Access Port (TAP) equipment is unfit for deployment in the virtual datapaths configured for server virtualization. Virtual TAP (vTAP), which is a software version of the hardware TAP, overcomes this problem by duplicating packets in a virtual switch. However, implementation of vTAP in a virtual switch has a performance problem because it shares the computing resources of the host machines with virtual switch and other VMs. We propose a vTAP implementation technique based on the extended Berkeley Packet Filter (eBPF), which is a high-speed packet processing technology, and compare its performance with that of the existing vTAP.

The Impact of Metaverse Development and Application on Industry and Society (메타버스의 발전과 적용이 산업과 사회에 미치는 영향)

  • Moon, Seung Hyeog
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.3
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    • pp.515-520
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    • 2022
  • Metaverse is at the center of heated debates in many areas recently. Coupled with real world, metaverse is extending its domain into social and cultural activities in addition to economic value creation as untact activities increase. Global companies are investing in R&D for metaverse. The reason is that metaverse is supposed to create new value by converging virtual and real worlds thanks to technology advancement such as AI, big data, 3D graphic, 5G, cloud computing, etc. Thus, innovative changes are expected in the economic, social and cultural areas. However, there are many problems to be solved yet for connecting virtual world and real one. Also, epoch-making development of products and services should be done for realistic experience and profit creation using virtual space in various industries beyond untact social activities against pandemic situation. The essence, present condition, development and its application areas of metaverse will be analyzed, and expected problems researched so that the strategy and methodology for securing global competitiveness will be addressed in coming metaverse era.

Topology Design Optimization and Experimental Validation of Heat Conduction Problems (열전도 문제에 관한 위상 최적설계의 실험적 검증)

  • Cha, Song-Hyun;Kim, Hyun-Seok;Cho, Seonho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.1
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    • pp.9-18
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    • 2015
  • In this paper, we verify the optimal topology design for heat conduction problems in steady stated which is obtained numerically using the adjoint design sensitivity analysis(DSA) method. In adjoint variable method(AVM), the already factorized system matrix is utilized to obtain the adjoint solution so that its computation cost is trivial for the sensitivity. For the topology optimization, the design variables are parameterized into normalized bulk material densities. The objective function and constraint are the thermal compliance of the structure and the allowable volume, respectively. For the experimental validation of the optimal topology design, we compare the results with those that have identical volume but designed intuitively using a thermal imaging camera. To manufacture the optimal design, we apply a simple numerical method to convert it into point cloud data and perform CAD modeling using commercial reverse engineering software. Based on the CAD model, we manufacture the optimal topology design by CNC.

A Study on the Awareness of Librarians for the Establishment of the Policy of the Joint Preservation Archive in Chungnam Library (충남도서관 공동보존자료관 운영정책 수립을 위한 사서 인식조사 연구)

  • Kwak, Seung-Jin;Noh, Younghee;Kang, Eun Yeong;Kim, Jeong-Taek;Kwak, Woojung
    • Journal of the Korean Society for Library and Information Science
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    • v.54 no.4
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    • pp.27-51
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    • 2020
  • Regional representative libraries are installing joint preservation archives to solve the problem of lack of preservation space in libraries. This study conducted a survey of public library librarians through a questionnaire survey and an FGI method in order to prepare specific operational policies and implementation plans for the Chungnam Library Joint Preservation Archive, which is a regional representative library. Based on this, an operation policy and implementation plan suitable for the common preservation and use of printed and digital data, which is the goal of the Common Preservation Archive, was proposed. As a result of the study, first, the joint preservation library of the Chungnam Library should first transfer books and serials along with ownership in consideration of the condition and demand of the preservation space of participating libraries. Second, it is necessary to establish an operation management system that can be used by all participating libraries in order to quickly and conveniently operate the joint preservation data center and connect it with a cloud-based integrated data management system. Third, a plan for digitizing and archiving data that was judged to be digitized in the Common Preservation Archive was proposed.

Analysis of Literatures Related to Crop Growth and Yield of Onion and Garlic Using Text-mining Approaches for Develop Productivity Prediction Models (양파·마늘 생산성 예측 모델 개발을 위한 텍스트마이닝 기법 활용 생육 및 수량 관련 문헌 분석)

  • Kim, Jin-Hee;Kim, Dae-Jun;Seo, Bo-Hun;Kim, Kwang Soo
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.23 no.4
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    • pp.374-390
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    • 2021
  • Growth and yield of field vegetable crops would be affected by climate conditions, which cause a relatively large fluctuation in crop production and consumer price over years. The yield prediction system for these crops would support decision-making on policies to manage supply and demands. The objectives of this study were to compile literatures related to onion and garlic and to perform data-mining analysis, which would shed lights on the development of crop models for these major field vegetable crops in Korea. The literatures on crop growth and yield were collected from the databases operated by Research Information Sharing Service, National Science & Technology Information Service and SCOPUS. The keywords were chosen to retrieve research outcomes related to crop growth and yield of onion and garlic. These literatures were analyzed using text mining approaches including word cloud and semantic networks. It was found that the number of publications was considerably less for the field vegetable crops compared with rice. Still, specific patterns between previous research outcomes were identified using the text mining methods. For example, climate change and remote sensing were major topics of interest for growth and yield of onion and garlic. The impact of temperature and irrigation on crop growth was also assessed in the previous studies. It was also found that yield of onion and garlic would be affected by both environment and crop management conditions including sowing time, variety, seed treatment method, irrigation interval, fertilization amount and fertilizer composition. For meteorological conditions, temperature, precipitation, solar radiation and humidity were found to be the major factors in the literatures. These indicate that crop models need to take into account both environmental and crop management practices for reliable prediction of crop yield.

Development of a complex failure prediction system using Hierarchical Attention Network (Hierarchical Attention Network를 이용한 복합 장애 발생 예측 시스템 개발)

  • Park, Youngchan;An, Sangjun;Kim, Mintae;Kim, Wooju
    • Journal of Intelligence and Information Systems
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    • v.26 no.4
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    • pp.127-148
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    • 2020
  • The data center is a physical environment facility for accommodating computer systems and related components, and is an essential foundation technology for next-generation core industries such as big data, smart factories, wearables, and smart homes. In particular, with the growth of cloud computing, the proportional expansion of the data center infrastructure is inevitable. Monitoring the health of these data center facilities is a way to maintain and manage the system and prevent failure. If a failure occurs in some elements of the facility, it may affect not only the relevant equipment but also other connected equipment, and may cause enormous damage. In particular, IT facilities are irregular due to interdependence and it is difficult to know the cause. In the previous study predicting failure in data center, failure was predicted by looking at a single server as a single state without assuming that the devices were mixed. Therefore, in this study, data center failures were classified into failures occurring inside the server (Outage A) and failures occurring outside the server (Outage B), and focused on analyzing complex failures occurring within the server. Server external failures include power, cooling, user errors, etc. Since such failures can be prevented in the early stages of data center facility construction, various solutions are being developed. On the other hand, the cause of the failure occurring in the server is difficult to determine, and adequate prevention has not yet been achieved. In particular, this is the reason why server failures do not occur singularly, cause other server failures, or receive something that causes failures from other servers. In other words, while the existing studies assumed that it was a single server that did not affect the servers and analyzed the failure, in this study, the failure occurred on the assumption that it had an effect between servers. In order to define the complex failure situation in the data center, failure history data for each equipment existing in the data center was used. There are four major failures considered in this study: Network Node Down, Server Down, Windows Activation Services Down, and Database Management System Service Down. The failures that occur for each device are sorted in chronological order, and when a failure occurs in a specific equipment, if a failure occurs in a specific equipment within 5 minutes from the time of occurrence, it is defined that the failure occurs simultaneously. After configuring the sequence for the devices that have failed at the same time, 5 devices that frequently occur simultaneously within the configured sequence were selected, and the case where the selected devices failed at the same time was confirmed through visualization. Since the server resource information collected for failure analysis is in units of time series and has flow, we used Long Short-term Memory (LSTM), a deep learning algorithm that can predict the next state through the previous state. In addition, unlike a single server, the Hierarchical Attention Network deep learning model structure was used in consideration of the fact that the level of multiple failures for each server is different. This algorithm is a method of increasing the prediction accuracy by giving weight to the server as the impact on the failure increases. The study began with defining the type of failure and selecting the analysis target. In the first experiment, the same collected data was assumed as a single server state and a multiple server state, and compared and analyzed. The second experiment improved the prediction accuracy in the case of a complex server by optimizing each server threshold. In the first experiment, which assumed each of a single server and multiple servers, in the case of a single server, it was predicted that three of the five servers did not have a failure even though the actual failure occurred. However, assuming multiple servers, all five servers were predicted to have failed. As a result of the experiment, the hypothesis that there is an effect between servers is proven. As a result of this study, it was confirmed that the prediction performance was superior when the multiple servers were assumed than when the single server was assumed. In particular, applying the Hierarchical Attention Network algorithm, assuming that the effects of each server will be different, played a role in improving the analysis effect. In addition, by applying a different threshold for each server, the prediction accuracy could be improved. This study showed that failures that are difficult to determine the cause can be predicted through historical data, and a model that can predict failures occurring in servers in data centers is presented. It is expected that the occurrence of disability can be prevented in advance using the results of this study.

Terrain Shadow Detection in Satellite Images of the Korean Peninsula Using a Hill-Shade Algorithm (음영기복 알고리즘을 활용한 한반도 촬영 위성영상에서의 지형그림자 탐지)

  • Hyeong-Gyu Kim;Joongbin Lim;Kyoung-Min Kim;Myoungsoo Won;Taejung Kim
    • Korean Journal of Remote Sensing
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    • v.39 no.5_1
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    • pp.637-654
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    • 2023
  • In recent years, the number of users has been increasing with the rapid development of earth observation satellites. In response, the Committee on Earth Observation Satellites (CEOS) has been striving to provide user-friendly satellite images by introducing the concept of Analysis Ready Data (ARD) and defining its requirements as CEOS ARD for Land (CARD4L). In ARD, a mask called an Unusable Data Mask (UDM), identifying unnecessary pixels for land analysis, should be provided with a satellite image. UDMs include clouds, cloud shadows, terrain shadows, etc. Terrain shadows are generated in mountainous terrain with large terrain relief, and these areas cause errors in analysis due to their low radiation intensity. previous research on terrain shadow detection focused on detecting terrain shadow pixels to correct terrain shadows. However, this should be replaced by the terrain correction method. Therefore, there is a need to expand the purpose of terrain shadow detection. In this study, to utilize CAS500-4 for forest and agriculture analysis, we extended the scope of the terrain shadow detection to shaded areas. This paper aims to analyze the potential for terrain shadow detection to make a terrain shadow mask for South and North Korea. To detect terrain shadows, we used a Hill-shade algorithm that utilizes the position of the sun and a surface's derivatives, such as slope and aspect. Using RapidEye images with a spatial resolution of 5 meters and Sentinel-2 images with a spatial resolution of 10 meters over the Korean Peninsula, the optimal threshold for shadow determination was confirmed by comparing them with the ground truth. The optimal threshold was used to perform terrain shadow detection, and the results were analyzed. As a qualitative result, it was confirmed that the shape was similar to the ground truth as a whole. In addition, it was confirmed that most of the F1 scores were between 0.8 and 0.94 for all images tested. Based on the results of this study, it was confirmed that automatic terrain shadow detection was well performed throughout the Korean Peninsula.

Analysis of Two-Dimensional Pollutant Transport in Meandering Streams (사행하천에서 오염물질의 2차원 거동특성 해석)

  • Oh, Jung-Sun;Seo, Il-Won;Kim, Young-Han
    • Journal of Korea Water Resources Association
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    • v.37 no.12
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    • pp.979-991
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    • 2004
  • In this study, RMA2 and RMA4, the 2-D depth-averaged models, were employed to simulate the two-dimensional mixing characteristics of the pollutants in the natural streams. The velocity and depth were first calculated using RMA2, 2-D hydrodynamic model, and then the resulting flow field was inputted to RMA4, 2-D water quality model, to compute the concentration field. RMA models were verified using the velocity and concentration data measured in S-curved meandering channel. The results showed that the RMA2 model simulated well the phenomenon that the maximum velocity line is located at the Inner bank of meandering channel, and the RMA4 model was well adapted to reproduce the general mixing behavior and the separation of tracer clouds. Comparing model simulations with measured data in the field experiments, RMA2 model simulated well general flow field and tendency that the maximum velocity line skewed toward the outer bank which were found in field experiments. The simulations of RMA4 model showed that the center of the tracer cloud tends to follow the path in which the maximum velocity occurs. In this study, the dispersion coefficients are fine-tuned based on the measured coefficients calculated using field concentration data, and the results show reasonable agreement with predictive equations.