• Smart Structures and Systems
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• 제22권5호
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• pp.509-525
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• 2018

Sensors and systems in Civionics technology play an important role for continuously facilitating real-time structure monitoring systems by detecting and locating damage to or degradation of structures. An advanced materials, design processes, long-term sensing ability of sensors, electromagnetic interference, sensor placement techniques, data acquisition and computation, temperature, harsh environments, and energy consumption are important issues related to sensors for structural health monitoring (SHM). This paper provides a comprehensive survey of various sensor technologies, sensor classes and sensor networks in Civionics research for existing SHM systems. The detailed classification of sensor categories, applications, networking features, ranges, sizes and energy consumptions are investigated, summarized, and tabulated along with corresponding key references. The current challenges facing typical sensors in Civionics research are illustrated with a brief discussion on the progress of SHM in future applications. The purpose of this review is to discuss all the types of sensors and systems used in SHM research to provide a sufficient background on the challenges and problems in optimizing design techniques and understanding infrastructure performance, behavior and current condition. It is observed that the most important factors determining the quality of sensors and systems and their reliability are the long-term sensing ability, data rate, types of processors, size, power consumption, operation frequency, etc. This review will hopefully lead to increased efforts toward the development of low-powered, highly efficient, high data rate, reliable sensors and systems for SHM.

• 한국지리정보학회지
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• 제15권2호
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• pp.46-56
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• 2012

최근 소프트웨어 아키텍처 설계 시 재사용성의 효율성이 강조되어지고 있다. 이러한 설계의 재사용성은 소프트웨어의 품질을 높이고 유지보수 효율을 높일 수 있는 비용절감 요소로 많이 활용된다. 이러한 재사용관련 객체지향 설계에서 GoF 디자인 패턴은 반복적인 설계 문제에 대해 재사용성이 높은 해법을 제공하므로 그 중요성이 더욱 강조되고 있다. 이와 관련한 설계방법이 여러 응용시스템에서 적용되고 있다. 이중 다중 분산 센서네트워크 시스템에서 서로 다른 기능의 센서노드, 수집노드와 서버에서 수많은 컴포넌트와 클래스의 조합으로 시스템이 설계되어 복잡한 구조를 이루고 있다. 더군다나 이러한 시스템들은 개발자의 특정 목적에 맞추어 더욱 복잡한 시스템으로 변경되기도 한다. 본 논문은 TinyOS에 기반한 다중 분산되어진 센서네트워크 시스템에서 복잡하게 구현되어 있는 구조들을 클래스와 기능 등에 따라 재사용성의 효율성을 높이는 CATL 모델 구조를 설계하고 Facade 패턴을 응용하여 센서네트워크 시스템을 설계 하고자 한다. 이러한 모델구조와 패턴은 복잡한 센서네트워크 시스템에서 주요 기능들을 담당하는 클래스와 기능 들을 묶어 구조화함으로서 새로운 시스템의 설계나 변경 또는 유지보수 등에 효율적으로 활용될 것이라 판단된다.

• Journal of Biosystems Engineering
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• 제22권1호
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• pp.49-58
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• 1997

Finding of internal quality is crucial for getting under control quality of watermelon after harvest. A maturity sensing device of watermelon using repulsion characteristics was developed and evaluated. In this study, five different sensing probes were used to detect the physical changes after impact on watermelons. Total 15 watermelons were tested and evaluated into two classes: ripe and unripe. It was difficult to detect the overripe watermelons using the proposed sensor. Therefore, the results showed that the developed sensor could be used to separate unripe watermelons after harvest. The results from this study are summarized as follows. 1. It was successful to distinguish between the ripe and unripe watermelon by sensing the elastic characteristics on impact. 2. The hemisphere was best for the shape of sensing part because the hemisphere concentrate stress in impact part. 3. Among the five type developed sensor, the 1, 2, 3. 5-type sensor showed good character in distinguishing between ripe and unripe watermelon.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권1호
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• pp.178-202
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• 2012

In this paper, we first survey cross-layer architectures for Wireless Sensor Networks (WSNs) and Wireless Multimedia Sensor Networks (WMSNs). Afterwards, we propose a novel cross-layer architecture for QoS provisioning in clustered and multi-hop based WMSNs. The proposed architecture provides support for multiple network-based applications on a single sensor node. For supporting multiple applications on a single node, an area in memory is reserved where each application can store its network protocols settings. Furthermore, the proposed cross-layer architecture supports heterogeneous flows by classifying WMSN traffic into six traffic classes. The architecture incorporates a service differentiation module for QoS provisioning in WMSNs. The service differentiation module defines the forwarding behavior corresponding to each traffic class. The forwarding behavior is primarily determined by the priority of the traffic class, moreover the service differentiation module allocates bandwidth to each traffic class with goals to maximize network utilization and avoid starvation of low priority flows. The proposal incorporates the congestion detection and control algorithm. Upon detection of congestion, the congested node makes an estimate of the data rate that should be used by the node itself and its one-hop away upstream nodes. While estimating the data rate, the congested node considers the characteristics of different traffic classes along with their total bandwidth usage. The architecture uses a shared database to enable cross-layer interactions. Application's network protocol settings and the interaction with the shared database is done through a cross-layer optimization middleware.

• International Journal of Control, Automation, and Systems
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• 제6권3호
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• pp.339-350
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• 2008

A general active fault-tolerant control framework is proposed for nonlinear systems with sensor faults. According to their identifiability, all sensor faults are divided into two classes: identifiable faults and non-identifiable faults. In the healthy case, the control objective is such that all outputs converge to their given set-points. A fault detection and isolation module is firstly built, which can produce an alarm when there is a fault in the system and also tell us which sensor has a fault. If the fault is identifiable, the control objective remains the same as in the healthy case; while if the fault is non-identifiable, the control objective degenerates to be such that only the healthy outputs converge to the set-points. A numerical example is given to illustrate the effectiveness and feasibility of the proposed method and encouraging results have been obtained.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.831-832
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• 2006

In this paper, we introduce a canonical framework of the large-scaled web-based sensor gateway and practically implement it as the environment monitoring system. The system consists of a central management server, up to 250 local embedded subsystems and up to 250 sensor or actuator nodes for each subsystem. The node information is gathered periodically through a well-defined protocol on the sensor network and converted to the web contents and the SNMP MIB objects according to its data type. The MIB objects are well-defined and include system, network, sensor, actuator and alarm specific data classes. Because there is an increasing trend that a large number of sites are willing to adapt unmanned sensing and control, the developed system will play a key role to efficiently manage a large scale sensor networked system such as environment monitoring systems or countermeasure systems against disaster and calamities.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.224-227
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• 2008

Land cover and its changes, affecting multiple aspects of the environmental system such as energy balance, biogeochemical cycles, hydrological cycles and the climate system, are regarded as critical elements in global change studies. Especially in arid and semiarid regions, the observation of ecosystem that is sensitive to climate change can improve an understanding of the relationships between climate and ecosystem dynamics. The purpose of this research is analyzing the ecosystem surrounding the Gobi desert in North Asia quantitatively as well as qualitatively more concretely. We used Normalized Difference Vegetation Index (NDVI) derived from SPOT-VEGETATION (VGT) sensor during 1999${\sim}$2007. Ecosystem monitoring of this area is necessary because it is a hot spot in global environment change. This study will allow predicting areas, which are prone to the rapid environmental change. Eight classes were classified and compare with MODerate resolution Imaging Spectrometer (MODIS) global land cover. The time-series analysis was carried out for these 8 classes. Class-1 and -2 have least amplitude variation with low NDVI as barren areas, while other vegetated classes increase in May and decrease in October (maximum value occurs in July and August). Although the several classes have the similar features of NDVI time-series, we detected a slight difference of inter-annual variation among these classes.

• Journal of Magnetics
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• 제10권3호
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• pp.122-127
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• 2005

New classes of LC resonators for micro magnetic sensor device were proposed and fabricated. The first type LC resonator (Type I) consists of a small piece of microwire and two cylindrical electrodes at the end of the microwire without direct contact to its ferromagnetic core. In type I resonator the ferromagnetic core of the microwire and cylindrical electrodes act as an inductor and two capacitors respectively to form a LC circuit. The second type LC resonator (Type II) consists of a solenoidal micro-inductor with a bundle of soft magnetic microwires as a core. The solenoidal micro-inductors fabricated by MEMS technique were $500\sim1,000\;\mu{m}$ in length with $10\sim20$ turns. A capacitor is connected in parallel to the micro-inductor to form a LC circuit. A tiny glass coated $CO_{83.2}B_{3.3}Si_{5.9}Mn_{7.6}$ microwire was fabricated by a glass-coated melt spinning technique. A supergiant magneto-impedance effect was found in a type I resonator as much as 400,000% by precise tuning frequency at around 518.51 MHz. In type II resonator the changes of inductance as a function of external magnetic field in micro-inductors with properly annealed microwire cores were varied as much as 370%. The phase angle between current and voltage was also strongly dependent on the magnetic field. The drastic increments of magnetoimpedance at near the resonance frequency were observed in both types of LC resonators. Accordingly, the sudden change of the phase angle, as large as $180^{\circ}C$, evidenced the occurrence of the resonance at a given external magnetic field.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 춘계학술대회
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• pp.611-613
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• 2015

멀티미디어 강의실에서는 자동 강의 저장뿐 아니라 카메라의 추적도 자동으로 추적하여 저장되도록 발전하고 있다. 기존의 추적 시스템은 별도의 센서를 몸에 부착하여 추적하거나 전면에 센서를 시공하여 추적하는 불편함이 있었고 동시에 여러명이 전면에 나타나면 에러가 발생하여 추적이 안된다거나 하는 문제점이 있었다. 본 논문에서는 Microsoft-Kinect 센서를 이용하여 화자(강사)의 위치 및 행동을 분석하며, 이를 PTZ 카메라 및 강의 저장 수업녹화 시스템과 연동하여 강의실 수업 녹화시에 효과적인 콘텐츠 생산을 가능하도록 하는 무인화자 추적 솔루션에 대하여 기술하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.237-243
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• 2004

A multichannel smart sound sensor capable to detect and identify sound events in noisy conditions is presented in this paper. Sound information extraction is a complex task and the main difficulty consists is the extraction of high­level information from an one-dimensional signal. The input of smart sound sensor is composed of data collected by 5 microphones and its output data is sent through a network. For a real time working purpose, the sound analysis is divided in three steps: sound event detection for each sound channel, fusion between simultaneously events and sound identification. The event detection module find impulsive signals in the noise and extracts them from the signal flow. Our smart sensor must be capable to identify impulsive signals but also speech presence too, in a noisy environment. The classification module is launched in a parallel task on the channel chosen by data fusion process. It looks to identify the event sound between seven predefined sound classes and uses a Gaussian Mixture Model (GMM) method. Mel Frequency Cepstral Coefficients are used in combination with new ones like zero crossing rate, centroid and roll-off point. This smart sound sensor is a part of a medical telemonitoring project with the aim of detecting serious accidents.