• 제목/요약/키워드: flow information

검색결과 5,726건 처리시간 0.031초

An Interior Point Method based Reactive Optimal Power Flow Incorporating Margin Enhancement Constraints

  • Song Hwa-Chang;Lee Byong-Jun;Moon Young-Hwan
    • KIEE International Transactions on Power Engineering
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    • 제5A권2호
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    • pp.152-158
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    • 2005
  • This paper describes a reactive optimal power flow incorporating margin enhancement constraints. Margin sensitivity at a steady-state voltage instability point is calculated using invariant space parametric sensitivity, and it can provide valuable information for selection of effective control parameters. However, the weakest buses in neighboring regions have high margin sensitivities within a certain range. Hence, the control determination using only the sensitivity information might cause violation of operational limits of the base operating point, at which the control is applied to enhance voltage stability margin in the direction of parameter increase. This paper applies an interior point method (IPM) to solve the optimal power flow formulation with the margin enhancement constraints, and shunt capacitances are mainly considered as control variables. In addition, nonlinearity of margin enhancement with respect to control of shunt capacitance is considered for speed-up control determination in the numerical example using the IEEE 118-bus test system.

국립중앙박물관 네비게이션시스템 이용자 만족도 연구: 플로우개념을 중심으로 (A Study on User Satisfaction in the Mobile Navigation Systems of National Museum of Korea : Focused on Flow Theory)

  • 김학희;이기동
    • 한국정보시스템학회지:정보시스템연구
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    • 제18권2호
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    • pp.19-34
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    • 2009
  • The purpose of this study is to analyze the influence of the flow concepts to the visitor's satisfaction in the mobile sensor-network navigation system. recently installed in the National Museum of Korea in Seoul. The satisfaction of visitor's on the facilities and services offered by the museum environment is crucial in that it provides a value-added learning experience for the visitor to immerse into the historical descriptions and cultural contents, often presented in digital formats. 200 subjects' data are analyzed using the structural equation model and the key results are presented. It is hoped thai our flow results show a new way of understanding of information technologies applied to the museum setting.

e-Trade의 SCM Process에 관한 연구 (A Study on the SCM Process in e-Trade)

  • 김명호
    • 한국정보통신학회논문지
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    • 제8권4호
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    • pp.918-925
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    • 2004
  • SCM은 제품을 생산하는 기업이 부품의 구매, 제조, 판매까지의 모든 일정을 수립하고 고객의 수요계획 및 물류현황을 체계적으로 정리, 제품의 흐름(부가가치 물자흐름)을 원활하고 효율적으로 수행할 수 있게 하는 것을 말한다. 본 논문에서는 SCM의 단순한 내부적 통합을 포함하여 공급망 전체의 정보흐름(소요량 정보흐름)을 유도할 수 있는 정부와 기업간 외부적 통합의 흐름을 분석하고 이에 따른 문제점과 개선방안을 제시하였다.

단안 비디오로부터의 5D 라이트필드 비디오 합성 프레임워크 (Deep Learning Framework for 5D Light Field Synthesis from Single Video)

  • 배규호;;박인규
    • 한국방송∙미디어공학회:학술대회논문집
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    • 한국방송∙미디어공학회 2019년도 하계학술대회
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    • pp.150-152
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    • 2019
  • 본 논문에서는 기존의 연구를 극복하여 단일 영상이 아닌 단안 비디오로부터 5D 라이트필드 영상을 합성하는 딥러닝 프레임워크를 제안한다. 현재 일반적으로 사용 가능한 Lytro Illum 카메라 등은 초당 3프레임의 비디오만을 취득할 수 있기 때문에 학습용 데이터로 사용하기에 어려움이 있다. 이러한 문제점을 해결하기 위해 본 논문에서는 가상 환경 데이터를 구성하며 이를 위해 UnrealCV를 활용하여 사실적 그래픽 렌더링에 의한 데이터를 취득하고 이를 학습에 사용한다. 제안하는 딥러닝 프레임워크는 두 개의 입력 단안 비디오에서 $5{\times}5$의 각 SAI(sub-aperture image)를 갖는 라이트필드 비디오를 합성한다. 제안하는 네트워크는 luminance 영상으로 변환된 입력 영상으로부터 appearance flow를 추측하는 플로우 추측 네트워크(flow estimation network), appearance flow로부터 얻어진 두 개의 라이트필드 비디오 프레임 간의 optical flow를 추측하는 광학 플로우 추측 네트워크(optical flow estimation network)로 구성되어있다.

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Piosk : A Practical Kiosk To Prevent Information Leakage

  • Lee, Suchul;Lee, Sungil;Oh, Hayoung;Han, Seokmin
    • International journal of advanced smart convergence
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    • 제8권2호
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    • pp.77-87
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    • 2019
  • One of important concerns in information security is to control information flow. It is whether to protect confidential information from being leaked, or to protect trusted information from being tainted. In this paper, we present Piosk (Physical blockage of Information flow Kiosk) that addresses both the problems practically. Piosk can forestall and prevent the leakage of information, and defend inner tangible assets against a variety of malwares as well. When a visitor who carries a re-writable portable storage device, must insert the device into Piosk installed next to the security gate. Then, Piosk scans the device at the very moment, and detects & repairs malicious codes that might be exist. After that, Piosk writes the contents (including sanitized ones) on a new read-only portable device such as a compact disk. By doing so, the leakage of internal information through both insiders and outsiders can be prevented physically. We have designed and prototyped Piosk. The experimental verification of the Piosk prototype implementation reveals that, Piosk can accurately detect every malware at the same detection level as Virus Total and effectively prevent the leakage of internal information. In addition, we compare Piosk with the state-of-the-art methods and describe the special advantages of Piosk over existing methods.

위성항법 불용 환경에서의 무인비행체 항법을 위한 광류 정보 활용 (Applicability of Optical Flow Information for UAV Navigation under GNSS-denied Environment)

  • 김동민;김태균;정회조;석진영;김승균;김연실;한상혁
    • 한국항행학회논문지
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    • 제24권1호
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    • pp.16-27
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    • 2020
  • 본 논문에서는 위성항법 불용 환경에서의 무인비행체 항법을 위한 광류 정보 활용에 관한 연구 내용을 기술한다. 광류 정보는 위성항법 불용 환경에서 수평 위치 및 속도 추정을 위해 중요한 측정값이므로 정확한 광류 정보의 획득은 필수적이다. 이에 광류 정보에 포함될 수 있는 바이어스를 추정하여 상쇄함으로써 추정 성능을 향상시킬 수 있는 항법 알고리즘을 제안한다. 제안된 알고리즘을 적용하여 검증하기 위해 유도, 항법, 제어 시스템을 설계하여 통합 시뮬레이션 환경을 구축한다. 이를 기반으로 수치 시뮬레이션을 수행하여 제안된 알고리즘을 분석한다.

Exploring Flow Characteristics in IPv6: A Comparative Measurement Study with IPv4 for Traffic Monitoring

  • Li, Qiang;Qin, Tao;Guan, Xiaohong;Zheng, Qinghua
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제8권4호
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    • pp.1307-1323
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    • 2014
  • With the exhaustion of global IPv4 addresses, IPv6 technologies have attracted increasing attentions, and have been deployed widely. Meanwhile, new applications running over IPv6 networks will change the traditional traffic characteristics obtained from IPv4 networks. Traditional models obtained from IPv4 cannot be used for IPv6 network monitoring directly and there is a need to investigate those changes. In this paper, we explore the flow features of IPv6 traffic and compare its difference with that of IPv4 traffic from flow level. Firstly, we analyze the differences of the general flow statistical characteristics and users' behavior between IPv4 and IPv6 networks. We find that there are more elephant flows in IPv6, which is critical for traffic engineering. Secondly, we find that there exist many one-way flows both in the IPv4 and IPv6 traffic, which are important information sources for abnormal behavior detection. Finally, in light of the challenges of analyzing massive data of large-scale network monitoring, we propose a group flow model which can greatly reduce the number of flows while capturing the primary traffic features, and perform a comparative measurement analysis of group users' behavior dynamic characteristics. We find there are less sharp changes caused by abnormity compared with IPv4, which shows there are less large-scale malicious activities in IPv6 currently. All the evaluation experiments are carried out based on the traffic traces collected from the Northwest Regional Center of CERNET (China Education and Research Network), and the results reveal the detailed flow characteristics of IPv6, which are useful for traffic management and anomaly detection in IPv6.

Extraction of Some Transportation Reference Planning Indices using High-Resolution Remotely Sensed Imagery

  • Lee, Ki-Won
    • 대한원격탐사학회지
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    • 제18권5호
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    • pp.263-271
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    • 2002
  • Recently, spatial information technologies using remotely sensed imagery and functionality of GIS (Geographic Information Systems) have been widely utilized to various types of transportation-related applications. In this study, extraction programs of some practical indices, to be effectively used in transportation reference planning problem, were designed and implemented as prototyped extensions in GIS development environment: traffic flow estimation (TFL/TFB), urban rural index (URI), and accessibility index (AI). In TFL/TFB, user can obtain quantitative results on traffic flow estimation at link/block using high-resolution satellite imagery. Whereas, URI extension provides urban-rural characteristics related to road system, being considered one of important factors in transportation planning. Lastly, AI extension helps to obtain accessibility index between nodes of road segments and surrounding district areas touched or intersected with the road network system, and it also provides useful information for transportation planning problems. This approach is regarded as one of RS-T (Remote Sensing in Transportation), and it is expected to expand as new application of remotely sensed imagery.

Enterprise 네트워크에서 Flow를 이용한 Host 분석 시스템 (Flow-based Host Analysis System on Enterprise Network)

  • 박진완;박상훈;김명섭
    • 한국정보처리학회:학술대회논문집
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    • 한국정보처리학회 2008년도 춘계학술발표대회
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    • pp.962-965
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    • 2008
  • 효율적인 네트워크 관리를 위해서는 해당 네트워크의 트래픽 분석 정보가 필요하다. 트래픽을 분석함에 있어 네트워크의 전체 트래픽에 대한 분석도 중요하지만, 총 호스트의 수, 호스트별 트래픽 현황, 호스트의 사용 중인 서비스 파악 등 호스트를 기반으로 한 트래픽 분석의 중요성이 날로 증가하고 있다. 본 논문에서는 호스트 트래픽 분석이 어떠한 정보를 제공해야 되는지 살펴보고, 해당 정보를 제공하는 Enterprise 네트워크 트래픽 분석 시스템을 설계하고 구현한 내용을 기술한다. 본 논문에서 설계 및 구현한 시스템은 기존의 Enterprise 네트워크에 적합한 Flow 기반의 실시간 트래픽 모니터링 시스템[1]을 확장시킨 형태로 호스트 트래픽 분석에 필요한 DB구성과 분석 정보 표현, 그리고 트래픽 추이 그래프 생성에 따른 유의 사항과 해결책을 제시한다. 본 논문에서 구축한 시스템은 학교 Campus 네트워크를 대상으로 구축되었다.

CGCM의 미래 기후 정보를 이용한 기후변화가 낙동강 유역 유황에 미치는 영향분석 (An Analysis of the Effect of Climate Change on Nakdong River Flow Condition using CGCM ' s Future Climate Information)

  • 김문성;고익환;김상단
    • 한국물환경학회지
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    • 제25권6호
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    • pp.863-871
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    • 2009
  • For the assessment of climate change impacts on river flow condition, CGCM 3.1 T63 is selected as future climate information. The projections come from CGCM used to simulate the GHG emission scenario known as A2. Air temperature and precipitation information from the GCM simulations are converted to regional scale data using the statistical downscaling method known as MSPG. Downscaled climate data from GCM are then used as the input data for the modified TANK model to generate regional runoff estimates for 44 river locations in Nakdong river basin. Climate change is expected to reduce the reliability of water supplies in the period of 2021~2030. In the period of 2051~2060, stream flow is expected to be reduced in spring season and increased in summer season. However, it should be noted that there are a lot of uncertainties in such multiple-step analysis used to convert climate information from GCM-based future climate projections into hydrologic information.