• Title/Summary/Keyword: system-identification methods

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Application-Level Traffic Monitoring and an Analysis on IP Networks

  • Kim, Myung-Sup;Won, Young-J.;Hong, James Won-Ki
    • ETRI Journal
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    • v.27 no.1
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    • pp.22-42
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    • 2005
  • Traditional traffic identification methods based on wellknown port numbers are not appropriate for the identification of new types of Internet applications. This paper proposes a new method to identify current Internet traffic, which is a preliminary but essential step toward traffic characterization. We categorized most current network-based applications into several classes according to their traffic patterns. Then, using this categorization, we developed a flow grouping method that determines the application name of traffic flows. We have incorporated our method into NG-MON, a traffic analysis system, to analyze Internet traffic between our enterprise network and the Internet, and characterized all the traffic according to their application types.

Updating of Finite Element Model and Joint Identification with Frequency Response Function (주파수응답함수를 이용한 유한요소모델의 개선 및 결합부 동정)

  • 서상훈;지태한;박영필
    • Journal of KSNVE
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    • v.7 no.1
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    • pp.61-69
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    • 1997
  • Despite of the development in the finite element method, it is difficult to get the finite element model describing the dynamic characteristics of the complex structure exactly. Therefore a number of different methods have been developed in order to update the finite element model of a structure using vibration test data. This paper outlines the basic formulation for the frequency response function based updating method. One important advantage of this method is that the intermediate step of performing an eigensolution extraction is unnecessary. Using simulated experimental data, studies are conducted in the case of 10 DOF discrete system. The solution of noisy and incomplete experimental data is discussed. True measured frequency response function data are used for updating the finite element model of a beam and a plate. Its applicability to the joint identification is also considered.

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Operational modal analysis for Canton Tower

  • Niu, Yan;Kraemer, Peter;Fritzen, Claus-Peter
    • Smart Structures and Systems
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    • v.10 no.4_5
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    • pp.393-410
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    • 2012
  • The 610 m high Canton Tower (formerly named Guangzhou New Television Tower) is currently considered as a benchmark problem for structural health monitoring (SHM) of high-rise slender structures. In the benchmark study task I, a set of 24-hour ambient vibration measurement data has been available for the output-only system identification study. In this paper, the vector autoregressive models (ARV) method is adopted in the operational modal analysis (OMA) for this TV tower. The identified natural frequencies, damping ratios and mode shapes are presented and compared with the available results from some other research groups which used different methods, e.g., the data-driven stochastic subspace identification (SSI-DATA) method, the enhanced frequency domain decomposition (EFDD) algorithm, and an improved modal identification method based on NExT-ERA technique. Furthermore, the environmental effects on the estimated modal parameters are also discussed.

Optimal Heating Load Identification using a DRNN (DRNN을 이용한 최적 난방부하 식별)

  • Chung, Kee-Chull;Yang, Hai-Won
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.10
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    • pp.1231-1238
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    • 1999
  • This paper presents an approach for the optimal heating load Identification using Diagonal Recurrent Neural Networks(DRNN). In this paper, the DRNN captures the dynamic nature of a system and since it is not fully connected, training is much faster than a fully connected recurrent neural network. The architecture of DRNN is a modified model of the fully connected recurrent neural network with one hidden layer. The hidden layer is comprised of self-recurrent neurons, each feeding its output only into itself. In this study, A dynamic backpropagation (DBP) with delta-bar-delta learning method is used to train an optimal heating load identifier. Delta-bar-delta learning method is an empirical method to adapt the learning rate gradually during the training period in order to improve accuracy in a short time. The simulation results based on experimental data show that the proposed model is superior to the other methods in most cases, in regard of not only learning speed but also identification accuracy.

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RFID Tag Protection using Face Feature

  • Park, Sung-Hyun;Rhee, Sang-Burm
    • Journal of the Semiconductor & Display Technology
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    • v.6 no.2 s.19
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    • pp.59-63
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    • 2007
  • Radio Frequency Identification (RFID) is a common term for technologies using micro chips that are able to communicate over short-range radio and that can be used for identifying physical objects. RFID technology already has several application areas and more are being envisioned all the time. While it has the potential of becoming a really ubiquitous part of the information society over time, there are many security and privacy concerns related to RFID that need to be solved. This paper proposes a method which could protect private information and ensure RFID's identification effectively storing face feature information on RFID tag. This method improved linear discriminant analysis has reduced the dimension of feature information which has large size of data. Therefore, face feature information can be stored in small memory field of RFID tag. The proposed algorithm in comparison with other previous methods shows better stability and elevated detection rate and also can be applied to the entrance control management system, digital identification card and others.

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A Development and Application of Methods of Identifying for the Elementary Gifted Children of Information Science (초등 정보과학영재를 위한 판별 방안 연구)

  • Hwang, Kuk-Hwan;Lee, Ae-Jung;Lee, Jae-Ho
    • Journal of The Korean Association of Information Education
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    • v.9 no.1
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    • pp.69-76
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    • 2005
  • The researcher conducts the following research to correctly identify the gifted children of science information. First, the researcher makes sufficient theoretic research on gifted children for the sake of definition and identification of the gifted children of information science, and reconstructed the identification principles, factors and procedures of the gifted children of information science on the basis of those of the gifted children of math and science the theories of a number of scholars and presented new methods of identifying new gifted children of information science. Second, the researcher set the identification procedures of the gifted children of information science and the relevant content and conducted the identification of gifted children through the observation and evaluation of sixth graders through three stages. Third, the researcher compares and analyzed the selected gifted children based on the identification procedures and ordinary groups of students excellent in math and science in terms of task achievement and looked into validity.

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Job Satisfaction, Subjective Class Identification and Associated Factors of Professional Socialization in Korean Physicians (의사집단의 전문직 사회화 과정과 사회적 지위 만족도, 경제적 보상 만족도 그리고 주관적 계층인식과의 관련성)

  • Yoon, Hyung-Gon;Hwang, In-Kyoung;Mun, Yeong-Bae;Lee, Hee-Young;Yoon, Seok-Jun
    • Journal of Preventive Medicine and Public Health
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    • v.41 no.1
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    • pp.30-38
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    • 2008
  • Objectives : The aim of this study was to determine the relationship between the core properties of professional socialization and social status satisfaction, economic reward satisfaction, and subjective class identification. Methods : Medical knowledge and skill, autonomy, and professional value factors were used as essential properties of professional socialization to determine the association with job satisfaction and subjective class identification. The authors used a self-administered questionnaire survey and collected nationwide data between July and August 2003, with 211 responses used for final analysis. Results : 'Age' and 'trust and respect' were positively associated with social status satisfaction, and 'occupation' was negatively associated. 'Income' and 'trust and respect' were positively related to economic reward satisfaction, and 'practicing for oneself', and 'a sense of duty and attendance' were negatively related. 'Practicing for oneself', 'not believing explanations', and 'a sense of duty and attendance' had a positive relationship with subjective class identification. 'Income', 'knowledge system', 'medical mistakes', 'treating like goods', 'meaning and joy', and 'trust and respect' had a negative relationship. Conclusions : The core property variables of professional socialization had a different relationship with social status satisfaction, economic reward satisfaction and subjective class identification. In particular, many core property variables were associated with subjective class identification positively or negatively. The development of professional socialization would help promote job satisfaction and subjective class identification.

The Development of a Computer-Assisted HACCP Program for the Microbiological Quality Assurance in Hospital Foodservice Operations (병원급식의 미생물적 품질보증을 위한 HACCP 전산프로그램의 개발)

  • Kwak, Tong-Kyung;Ryu, Kyung;Choi, Seong-Kyung
    • Journal of the Korean Society of Food Culture
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    • v.11 no.1
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    • pp.107-121
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    • 1996
  • This study was carried out to develop the computer-assisted Hazard Analysis and Critical Control Point (HACCP) program for a systematic approach to the identification, assessment and control of hazards for foodservice manager to assure the microbiological quality of food in hospital foodservice operations. Sanitation practices were surveyed and analyzed in the dietetic department of 4 hospitals. Among them, one 762-bed general hospital was selected as standard model to develop computer-assisted HACCP program. All data base files and processing programs were created by using Foxpro package for easy access of HACCP concept. HACCP program was developed based on the methods suggested by NACMCF, IAMFES and Bryan. This program consisted of two parts: the pre-stage for HACCP study and the implementation stage of the HACCP system. 1. Pre-stage for HACCP study includes the selection of menu item, the development of the HACCP recipe, the construction of a product flow diagram, and printing the HACCP recipe and a product flow diagram. A menu item for HACCP study can be selected from the menu item lists classified by cooking methods. HACCP recipe includes ingredients, their amount and cooking procedure. A flow diagram is constructed based on the HACCP recipe. The HACCP recipe and a product flow diagram are printed out. 2. Implementation of HACCP study includes the identification of microbiological hazards, the determination of critical control points, the establishment of control methods of each hazard, and the complementation of data base file. Potentially hazardous ingredients are determined and microbiological hazards are identified in each phase of the product flow. Critical control points (CCPs) are identified by applying CCP decision trees for ingredients and each process stage. After hazards and CCPs are identified, criteria, monitoring system, corrective action plan, record-keeping system and verification methods are established. When the HACCP study is complemented, HACCP study result forms are printed out. HACCP data base file can be either added, corrected or deleted.

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Vehicle Steering System Analysis for Enhanced Path Tracking of Autonomous Vehicles (자율주행 경로 추종 성능 개선을 위한 차량 조향 시스템 특성 분석)

  • Kim, Changhee;Lee, Dongpil;Yi, Kyongsu
    • Journal of Auto-vehicle Safety Association
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    • v.12 no.2
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    • pp.27-32
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    • 2020
  • This paper presents steering system requirements to ensure the stabilized lateral control of autonomous driving vehicles. The two main objectives of a lateral controller in autonomous vehicles are maintenance of vehicle stability and tracking of the desired path. Even if the desired steering angle is immediately determined by the upper level controller, the overall controller performance is greatly influenced by the specification of steering system actuators. Since one of the major inescapable traits that affects controller performance is the time delay of the steering actuator, our work is mainly focused on finding adequate parameters of high level control algorithm to compensate these response characteristics and guarantee vehicle stability. Actual vehicle steering angle response was obtained with Electric Power Steering (EPS) actuator test subject to various longitudinal velocity. Steering input and output response analysis was performed via MATLAB system identification toolbox. The use of system identification is advantageous since the transfer function of the system is conveniently obtained compared with methods that require actual mathematical modeling of the system. Simulation results of full vehicle model suggest that the obtained tuning parameter yields reduced oscillation and lateral error compared with other cases, thus enhancing path tracking performance.

A Study on the Verification Method for Railway System SIL (철도시스템 안전무결성레벨(SIL)의 검증방안에 대한 연구)

  • Park, Young-Soo
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.936-940
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    • 2007
  • This paper is about the study on the verification method for railway system SIL which is frequency of hazard, composing Risk, one of the measurement standards for railway system safety. Frequency of hazard can be identified by using FMECA, or HAZOP, and the assessment of identified dangerous failure rate should be done by systematic methods such as FTA. Therefore, this paper provides the hazard identification level for SIL verification and the requirements necessary to verify the integrity of analysis activity.

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