• Title/Summary/Keyword: structural monitoring

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Design and Implementation of Multi-Sensor based Smart Sensor Network using Mobile Devices (모바일 디바이스를 사용한 멀티센서 기반 스마트 센서 네트워크의 설계 및 구현)

  • Koo, Bon-Hyun;Choi, Hyo-Hyun;Shon, Tae-Shik
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.5
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    • pp.1-11
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    • 2008
  • Wireless Sensor Networks is applied to improvement of life convenience or service like U-City as well as environment pollution, tunnel and structural health monitoring, storm, and earthquake diagnostic system. To increase the usability of sensor data and applicability, mobile devices and their facilities allow the applications of sensor networks to give mobile users and actuators the results of event detection at anytime and anywhere. In this paper, we present MUSNEMO(Multi-sensor centric Ubiquitous Smart sensor NEtwork using Mobile devices) developed system for providing more efficient and valuable information services with a variety of mobile devices and network camera integrated to WSN. Our system is performed based on IEEE 802.15.4 protocol stack. To validate system usability, we built sensor network environments where were equipped with five application sensors such magnetic, photodiode, microphone, motion and vibration. We also built and tested proposed MUSNEMO to provide a novel model for event detection systems with mobile framework.

COMPARATIVE RESPONSES OF RICE (ORYZA SATIVA) STRAW TO UREA SUPPLEMENTATION AND UREA TREATMENT

  • Kumar, M.N.A.;Sundareshan, K.;Jagannath, E.G.;Sampath, S.R.;Doyle, P.T.
    • Asian-Australasian Journal of Animal Sciences
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    • v.4 no.1
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    • pp.91-97
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    • 1991
  • Twenty five 75% Holstein Friesian cross bred bullocks fed rice straw (Oryza sativa) of long form, were fed with the following five treatments. 1. Rice straw, untreated (RS) 2. RS + water (1:1), stored for 24 hours (WRS) 3. RS (100 kg) + urea solution (4 kg urea/100 litre water) and dried (USRS) 4. RS (100 kg) + urea solution (as in 3) stored in wet condition for 24 hours (UWRS) 5. RS (100 kg) + urea solution (as in 3) stored in pit for 21 days (UTRS). Potential digestibility of treatments of RS was evaluated by monitoring (in vitro) Simulating Rumen like Fermentation (SRLF). The results indicated that Dry Matter Intake (DMI), digestibility of nutrients, N utilization were of the order UTRS > UWRS > USRS > WRS and RS (p < 0.05 to p < 0.01). SRLF index was high (255.84) for UTRS and least (145.58) for USRS. It was intermediary (199.66) for UWRS. The acetyl content (AC) of UTRS with higher hemicellulose (HCE) digestibility (80.8%) was low compared to UWRS, USRS, RS and WRS. The acetate content was of the order UTRS < UWRS < USRS < WRS and RS thereby indicating that reduction in acetyl content was an index of positive response of urea-treatment of RS. In addition, the ratio of HCE/AC in faeces of UTRS was 0.87 as against the ratios (2.26-2.48) observed in other treatments recording reduction in AC due to urea-treatment. Among the treatments, USRS only supplemented N while UTRS in addition to utilization N, increased the digestibility of structural carbohydrates. Reduction in treatment time from 21 days to 1 day (UWRS) resulted in improvements similar to those of UTRS.

Water, Energy, Cooperation, and Conflict inthe Kura-Araks Basin of the South Caucasus

  • Campana, Michael E.
    • Proceedings of the Korea Water Resources Association Conference
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    • 2011.05a
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    • pp.3-3
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    • 2011
  • After the dissolution of the Soviet Union, the Kra-Araks Basin (KAB) became an international river basin with respect to the South Caucasus states of Armenia, Azerbaijan, and Georgia. However, there are no agreements regarding water allocation, water quality, or ecosystem maintenance among the aforementioned riparians. The main water problems in the basin include not only water quantity and quality, but also the lack of joint management. The aforementioned countries share many similar circumstances: location in a politically unstable but strategic region bureaucratic and structural issues; and more importantly, ongoing ethnic and related conflicts. Despite these obstacles, the countries recognize that they depend greatly on the basin, whose waters they must share. To that end, they proposed and participated in the joint NATO-OSCE South Caucasus River Monitoring (SCRMP) project between 2002 and 2009.The SCRMP sought to investigate and characterize the surface water quality in the KAB by providing equipment and training to all three countries. Several years' worth of water quality data were collected in the KAB: major ions; heavy metals; POPs (persistent organic pollutants); and radionuclides; The North Atlantic Treaty Organization (primary funder) and the Organization for Security and Co-operation in Europesupported the SCRMP not only to build capacity but also to promote cooperation and minimize conflict over water and other resources, thus providing a measure of security for Europe and other regions. The South Caucasus is a strategically-important region, functioning as a bridge between Asia and Europe. Energy-rich Azerbaijan seeks to become a key player in trade by serving as a transportation and energy hub between the energy and mineral-rich Central Asian KUT countries (Kazakhstan, Uzbekistan, and Turkmenistan) and Western Asia, Europe, and other areas. The presentation will summarize the scientific results of the SCRMP, elucidate the regional water-energy-security nexus, discuss future work in the region, and explain why the world needs to be concerned about the KAB and the entire South Caucasus.

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A Combination Strategy for Construction of Peptide-β2m-H-2Kb Single Chain with Overlap Extension PCR and One-Step Cloning

  • Xu, Tao;Li, Xiaoe;Wu, You;Shahzad, Khawar Ali;Wang, Wei;Zhang, Lei;Shen, Chuanlai
    • Journal of Microbiology and Biotechnology
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    • v.26 no.12
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    • pp.2184-2191
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    • 2016
  • The time-consuming and high-cost preparation of soluble peptide-major histocompatibility complexes (pMHC) currently limits their wide uses in monitoring antigen-specific T cells. The single-chain trimer (SCT) of peptide-${\beta}2m$-MHC class I heavy chain was developed as an alternative strategy, but its gene fusion is hindered in many cases owing to the incompatibility between the multiple restriction enzymes and the restriction endonuclease sites of plasmid vectors. In this study, overlap extension PCR and one-step cloning were adopted to overcome this restriction. The SCT gene of the $OVA_{257-264}$ peptide-$(GS_4)_3-{\beta}2m-(GS_4)_4-H-2K^b$ heavy chain was constructed and inserted into plasmid pET28a by overlap extension PCR and one-step cloning, without the requirement of restriction enzymes. The SCT protein was expressed in Escherichia coli, and then purified and refolded. The resulting $H-2K^b/OVA_{257-264}$ complex showed the correct structural conformation and capability to bind with $OVA_{257-264}$-specific T-cell receptor. The overlap extension PCR and one-step cloning ensure the construction of single-chain MHC class I molecules associated with random epitopes, and will facilitate the preparation of soluble pMHC multimers.

Self Diagnosis Technique of Concrete Structure Repaired and Strengthened by Carbon fiber Sheets Using Optical fiber Sensors (광섬유 센서를 이용한 탄소섬유시트 보수보강 콘크리트구조물에서의 자기진단기법)

  • Kim, Ki-Soo
    • Journal of the Korean Society for Nondestructive Testing
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    • v.23 no.2
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    • pp.133-139
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    • 2003
  • In order to extend the life time of building and civil infra-structure, nowadays, patch type fibrous composite materials are widely used. Repaired concrete columns and beams gain the stiffness and strength, but they lose toughness and show brittle failure. Usually, the cracks of concrete structures are visible with naked eyes and the status of the structure in the life cycle is estimated with visible inspection. After repairing of the structure, crack visibility is blocked by repaired carbon sheets. Therefore, structural monitoring after repairing is indispensible and self diagnosis method with optical fiber sensor is very useful. In this paper, peel-out effects is detected with optical fiber sensors and the strain difference between main structure and repaired carbon sheets when they separate each other.

Determination of Weighted Mean Temperature for the GPS Precipitable Water Vapor Estimation (GPS PWV 추정을 위한 가중 평균 온도식 결정)

  • Song Dong Seob;Yun Hong Sic
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.22 no.4
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    • pp.323-329
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    • 2004
  • Water vapor is an important parameter in monitoring changes in the Earth's climate and it can be used to improve weather forecasting. However, it haven't observed accurately by reasons of structural and economic problem of observation. GPS meteorology technique for precipitable water vapor measurement is currently actively being researched an advanced nation. Main issue of GPS meteorology is an accuracy of PWV measurement related weighted mean temperature and meteorological data. In this study, the korean weighted mean temperature had been recalculated by a linear regression method based on meteorological observations from 6 radiosonde stations for 2003 year. We examined the accuracy of PWV estimates from GPS observations and Radiosonde observations by new korean weighted mean temperature and others.

Damage Localization of Bridges with Variational Autoencoder (Variational Autoencoder를 이용한 교량 손상 위치 추정방법)

  • Lee, Kanghyeok;Chung, Minwoong;Jeon, Chanwoong;Shin, Do Hyoung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.40 no.2
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    • pp.233-238
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    • 2020
  • Most deep learning (DL) approaches for bridge damage localization based on a structural health monitoring system commonly use supervised learning-based DL models. The supervised learning-based DL model requires the response data obtained from sensors on the bridge and also the label which indicates the damaged state of the bridge. However, it is impractical to accurately obtain the label data in fields, thus, the supervised learning-based DL model has a limitation in that it is not easily applicable in practice. On the other hand, an unsupervised learning-based DL model has the merit of being able to train without label data. Considering this advantage, this study aims to propose and theoretically validate a damage localization approach for bridges using a variational autoencoder, a representative unsupervised learning-based DL network: as a result, this study indicated the feasibility of VAE for damage localization.

A Study on Reconstructing Impact Forces of an Aircraft Wing Using Impact Response Functions and Regularization Methods (충격응답함수와 조정법을 이용한 항공기 날개의 충격하중 복원 연구)

  • 박찬익
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.8
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    • pp.41-46
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    • 2006
  • The capability for reconstructing impact forces of an aircraft wing using impact response functions and regularization methods were examined. The impact response function which expresses the relation between the structure response and the impact force was derived using the information on mass and stiffness data of a finite element model for the wing. Iterative Tikhonov regularization method and generalized singular value decomposition method were used to inverse the impact response function that was generally ill-posed. For the numerical verification, a fighter aircraft wing was used. Strain and deflection histories obtained from finite element analysis were compared with the results calculated using impact response functions. And the impact forces were reconstructed with the strain histories obtained from finite element analysis. The numerical verification results showed that this method can be used to monitor impact forces on aircraft structures.

Simultaneous Measurement of Strain and Damage Signal in Composite Structures Using a Fiber Bragg Grating Sensor (광섬유 브래그 격자 센서를 이용한 복합재 구조물의 변형률 및 파손신호 동시 측정)

  • Koh, Jong-In;Bang, Hyung-Joon;Kim, Chun-Gon;Hong, Chang-Sun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.32 no.7
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    • pp.43-50
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    • 2004
  • For the simultaneous measurement of strain and damage signal a fiber Bragg grating sensor system with a dual demodulator was proposed. The dual demodulator is composed of a demodulator using a tunable Fabry-Perot filter measuring the low-frequency signal with large magnitude such as strain and the other using a passive Mach-Zehnder interferometer detecting the high-frequency signal with small amplitude such as impact or damage signal. Using the proposed fiber Bragg grating sensor system, both the strain and damage signals of a cross-ply laminated composite beam under tensile loading were simultaneously measured. The strain and damage signals detected by single fiber Bragg grating sensor showed that sudden strain shifts were accompanied with vibration at a maximum frequency of several hundreds of kilohertz at the instant of matrix crack propagation in the 90 degree layer in composite beam.

Identification of Impact Damage in Smart Composite Laminates Using PVDF Sensor Signals (고분자 압전센서 신호를 이용한 스마트 복합적층판의 충격 손상 규명)

  • Lee, Hong-Young;Kim, In-Gul;Park, Chan-Yik
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.32 no.7
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    • pp.51-59
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    • 2004
  • An experimental procedure to identify failure modes of impact damage using sensor signals and to analyze their general features is examined. A series of low-velocity impact tests from low energy to damage-induced high energy were performed on the instrumented drop weight impact tester to monitor the stress wave signals due to failure modes such as matrix cracking, delamination, and fiber breakage. The wavelet transform(WT) and Short Time Fourier Transform(STFT) are used to decompose the piezoelectric sensor signals in this study. The extent of the damage in each case was examined by means of a conventional ultrasonic C-scan. The PVDF sensor signals are shown to carry important information regarding the nature of the impact process that can be extracted from the careful signal processing and analysis.