• Title/Summary/Keyword: operational estimation

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Operational Reliability Analysis of Guided Weapon Systems (유도무기 시스템의 운용 신뢰도 분석)

  • Ha, Ju Seok;Kim, Kyung Mo
    • Convergence Security Journal
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    • v.17 no.3
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    • pp.95-101
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    • 2017
  • Reliability is the priority matter in guided weapon systems. The reliability prediction data is used during the devel opment stage as the manufacturing cost is very high and the production quantity if quite limited. At the same time it takes relatively a long period of time to acquire a reliable operation data set after deployment such that in order t o determine the operational reliability, weapons must be tested and analyzed in real operating environments. For the research, the life distributions were estimated by using actual operation data and the reliability was calculated by ap plying the method of least squares and maximum likelihood estimation. Also, the comparisons were made between pr edicted reliability and actual operational reliability. As a result, the actual reliability of each system was higher than predicted reliability and it was considered that such a difference was caused by the fact that the application of the l atest designing technology and improved parts to the guided weapon systems was not reflected on the estimation of predicted reliability. It was possible to confirm the actual operational reliability of domestic (ROK) guided weapon sy stems through this research and the methods used here will contribute to the reliability analyses for the future guide d weapon systems to be developed.

Dynamic Response Measurements and Analysis on a 10 kW Class Vertical Axis Wind Turbine (10 kW급 수직축 풍력터빈에 대한 구조물 동적응답 계측 및 분석)

  • Yi, Jin-Hak;Kim, Wonsul;Han, Taek Hee;Yim, Sungyul
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.27 no.1
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    • pp.107-113
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    • 2017
  • The dynamic characteristics including natural frequencies and excitation frequencies are evaluated for a small 10 kW vertical axis wind turbine. Acceleration responses were measured at 12 distributed locations for impact vibration tests, ambient vibration tests during non-operational and operational conditions, and braking tests during operational condition. The natural frequencies for the lowest 2 bending modes and the first torsional mode were estimated and also the excitation frequencies, i.e. 1P, 2P, 4P, were also estimated according to the rotational speed using the responses under operational conditions (i.e. power generation condition).

Damage detection and localization on a benchmark cable-stayed bridge

  • Domaneschi, Marco;Limongelli, Maria Pina;Martinelli, Luca
    • Earthquakes and Structures
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    • v.8 no.5
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    • pp.1113-1126
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    • 2015
  • A damage localization algorithm based on Operational Deformed Shapes and known as Interpolation Damage Detection Method, is herein applied to the finite element model of a cable stayed bridge for detecting and localizing damages in the stays and the supporting steel beams under the bridge deck. Frequency Response Functions have been calculated basing on the responses of the bridge model to low intensity seismic excitations and used to recover the Operational Deformed Shapes both in the transversal and in the vertical direction. The analyses have been carried in the undamaged configuration and repeated in several different damaged configurations. Results show that the method is able to detect the damage and its correct location, provided an accurate estimation of the Operational Deformed Shapes is available. Furthermore, the damage detection algorithm results effective also when damages coexist at the same time at several location of the cable-stayed bridge members.

The Least Absolute Deviations Estimation of the Contingent Valuation Model (조건부가치측정모형의 최소절대편차추정)

  • Kim, Dongil
    • Environmental and Resource Economics Review
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    • v.10 no.4
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    • pp.515-545
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    • 2001
  • This paper introduces the least absolute deviations estimation of the contingent valuation model, which corresponds to the semi-parametric estimation of discrete choice models by Manski (1975, 1985) and Lee (1992). The least absolute deviations estimation is more robust to mis-specified distributional assumptions in the estimation of the contingent valuation model, compared to the maximum likelihood estimation. The full identification and strong consistency of the estimation are proved and its application to different formats of contingent valuation survey data is discussed. Simulation studies are designed to evaluate its operational characteristics including computational strategies, small sample properties and the efficiency gain of a follow-up question. The bias and efficiency of least absolute deviations and maximum likelihood estimation are compared in the presence of heteroskedasticity.

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Stream Discharge Estimation by Hydraulic Channel Routing and Stage Measurement (수위관측과 수리학적 하도추적에 의한 하천유량 간접추정)

  • Lee, Sang-Ho;Gang, Sin-Uk
    • Journal of Korea Water Resources Association
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    • v.34 no.5
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    • pp.543-549
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    • 2001
  • This research estimated stream discharges indirectly by hydraulic channel routing. Only stage data from three stage stations and river cross section data were used to estimate Manning roughness coefficients and to compute stream discharges. When the discharges were estimated a stage-stage set of conditions was used for upstream-downstream boundary conditions. The research used the data from the upper Mississippi River. The hydraulic channel routings were performed by DWOPER (operational dynamic wave model). The global optimization program of SCE-UA was used to improve the roughness coefficient estimation module of the modified Newton-Raphson method in DWOPER. The results from SCE-US were better. For the case study of a flood, most estimated discharges except a few show errors within 10%.

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Operation load estimation of chain-like structures using fiber optic strain sensors

  • Derkevorkian, Armen;Pena, Francisco;Masri, Sami F.;Richards, W. Lance
    • Smart Structures and Systems
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    • v.20 no.3
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    • pp.385-396
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    • 2017
  • The recent advancements in sensing technologies allow us to record measurements from target structures at multiple locations and with relatively high spatial resolution. Such measurements can be used to develop data-driven methodologies for condition assessment, control, and health monitoring of target structures. One of the state-of-the-art technologies, Fiber Optic Strain Sensors (FOSS), is developed at NASA Armstrong Flight Research Center, and is based on Fiber Bragg Grating (FBG) sensors. These strain sensors are accurate, lightweight, and can provide almost continuous strain-field measurements along the length of the fiber. The strain measurements can then be used for real-time shape-sensing and operational load-estimation of complex structural systems. While several works have demonstrated the successful implementation of FOSS on large-scale real-life aerospace structures (i.e., airplane wings), there is paucity of studies in the literature that have investigated the potential of extending the application of FOSS into civil structures (e.g., tall buildings, bridges, etc.). This work assesses the feasibility of using FOSS to predict operational loads (e.g., wind loads) on chain-like structures. A thorough investigation is performed using analytical, computational, and experimental models of a 4-story steel building test specimen, developed at the University of Southern California. This study provides guidelines on the implementation of the FOSS technology on building-like structures, addresses the associated technical challenges, and suggests potential modifications to a load-estimation algorithm, to achieve a robust methodology for predicting operational loads using strain-field measurements.

Air-Data Estimation for Air-Breathing Hypersonic Vehicles

  • Kang, Bryan-Heejin
    • Transactions on Control, Automation and Systems Engineering
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    • v.1 no.1
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    • pp.75-86
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    • 1999
  • An air-data estimator for generic air-breathing hypersonic vehicles (AHSVs) is developed and demonstrated with an example vehicle configuration. The AHSV air-data estimation strategy emphasized improvement of the angle of attack estimate accuracy to a degree necessitated by the stringent operational requirements of the air-breathing propulsion. the resulting estimation problem involves highly nonlinear diffusion process (propagation); consequently, significant distortion of a posteriori conditional density is suspected. A simulation based statistical analysis tool is developed to characterize the nonlinear diffusion process. The statistical analysis results indicate that the diffusion process preserves the symmetry and unimodality of initial probability density shape state variables, and provide the basis for applicability of an Extended Kalman Filter (EKF). An EKF is designed for the AHSV air-data system and the air data estimation capabilities are demonstrated.

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Parameter Estimation of The Distributed System via Improved Block Pulse Coefficients Estimation

  • Kim, Tai-hoon;Shim, Jae-sun
    • 제어로봇시스템학회:학술대회논문집
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    • 2002.10a
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    • pp.61.6-61
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    • 2002
  • In these days, Block Pulse functions are used in a variety of fields such as the analysis and controller design of the systems. In applying the Block Pulse function technique to control and systems science, the integral operation of the Block Pulse series plays important roles. This is because differential equations are always involved in the representations of continuous-time models of dynamic systems, and differential operations are always approximated by the corresponding Block Pulse series through integration operational matrices. In order to apply the Block Pulse function technique to the problems of continuous-time dynamic systems more efficiently, it is necessary to find th...

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The Estimation of Cutoff Connection Rates on the ATM Switching System Using Simulation (시뮬레이션을 이용한 ATM 교환기 연결 절단율 추정 연구)

  • 정명기
    • Journal of the Korea Society for Simulation
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    • v.6 no.2
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    • pp.117-124
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    • 1997
  • A simulation model for the estimation of cutoff connection rate in the asynchronous transfer mode (ATM) switching system under multimedia traffic environments is presented. The simulator is developed by the integration of the AweSim tool with user-written C++ routines that model the internal structures of operational details of the switching system. For the case study, the simulator is applied to the ATM switching system developed by Electronics and Telecommunications Research Institute (ETRI) to compare design alternatives according to the cutoff connection rates.

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A Study on the Operational Stage Reliability of Dedicated Software (주문형 소프트웨어의 운영단계 신뢰도에 관한 연구)

  • Che, Gyu-Shik
    • The KIPS Transactions:PartD
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    • v.10D no.5
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    • pp.837-844
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    • 2003
  • The software reliability have to be improved as one major method to enhance the quality of developed software, and its defect is detected and modified through testing as a direct way to meet the purpose before releasing. Once its reliability grows up to the target and it is released to public. there nay be operational reliability problem. The operational software reliability trend nay be different depending on the condition whether it is universal or dedicated. And its reliability estimation is changed based on the condition if it follows uniform testing efforts or Weibull testing efforts. I study the operational reliability trend of dedicated software, applying two case testing efforts for the released item.