• 소음진동
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• 제7권3호
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• pp.377-386
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• 1997

A cantilever type piezoceramic vibration sensor was developed that could make up for the short-comings of current vibration sensors, such as high price, low sensitivity, and complex structure. For the design, in conjunction with piezoelectric constitutive equations, we derived full analytic response equations of the piezoelectric bimorph sensor to external forces. The external forces were supposed to take the form of either step or sinusoidal force. Based on the results, actual piezoelectric vibration sensors were fabricated and tested for verification of the theoretical results. Further, comparison of the performance of the developed sensor was made with that of a commercially available representative vibration sensor so that quantitative evaluation of its sensitivity could be made. The sensor developed in this work showed excellent sensitivity and thermal stability in addition to the merits of simple structure and low fabrication cost in comparison with conventional mass-loaded piezoelectric sensors.

• Journal of information and communication convergence engineering
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• 제5권4호
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• pp.300-304
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• 2007

Wireless sensor networks represent a new and exciting communication paradigm which could have multiple applications in future wireless communication. Therefore, performance analysis of such a wireless sensor network paradigm is needed in complex wireless channel. Wireless networks could be an important means of providing ubiquitous communication in the future. In this paper, the BER performance of uniform distributed wireless sensor networks is evaluated in non-Gaussian noise channel. Using an analytical approach, the impact of Av. BER performance relating the coherent BPSK system at the end of a multi-hop route versus the spatial density of sensor nodes and impulsive noise parameters A and $\Gamma$ is evaluated.

• Bulletin of the Korean Chemical Society
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• 제33권1호
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• pp.319-321
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• 2012

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2275-2277
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• 1998

This paper presents an algorithmic sensor value validation technique that can systematically explore the embedded sensor redundancies in complex physical systems and maximize their utilization in validating sensor values. The confidency criteria are developed for checking the consistency of sensor relationships called Causal Relations. Development results are applied to a tubular type supercritical pressure type thermal power plant with rated operational data to demonstrate the effectiveness of the proposed technique.

• 한국신뢰성학회지:신뢰성응용연구
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• 제5권4호
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• pp.465-486
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• 2005

A unreliable network system results in unsatisfied performance. A performance criterion of a network is throughput and availability. One of the most compelling technological advances of this decade has been the advent of deploying wireless networks of heterogeneous smart sensor nodes for complex information gathering tasks, The advancement and popularization of wireless communication technologies make more efficiency to network devices with wireless technology than with wired technology. Recently, the research of wireless sensor network has been drawing much attentions. In this paper, We evaluate throughput and availability of wireless sensor network, which have hierarchical structure based on clustering and estimate the maximum hroughput, average throughput and availability of the network considering several link failure patterns likely to happen at a cluster consisted of sensor nodes. Also increasing a number of sensor nodes in a cluster, We analysis the average throughput and availability of the network.

• 센서학회지
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• 제27권6호
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• pp.392-396
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• 2018

Structural color has many advantages over pigment based color. In recent years, researches are being conducted to apply these advantages to applications such as wearable devices. In this study, strain sensor, a kind of wearable device, was developed using structural color. The use of structural color has the advantage of not using energy and complex measuring equipment to measure strain rate. Wrinkle structure was fabricated on the surface of Poly-dimethylsiloxane (PDMS) and used it as a sensor which color changes according to the applied strain. In addition, a transmittance-changing sensor was developed and fabricated by synthesizing additional glass nanoparticles. Furthermore, a strain sensor was developed that is largely transparent at the target strain and opaque otherwise.

• 센서학회지
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• 제16권2호
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• pp.150-158
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• 2007

The IEEE 1451 publication are available, this standard defines interface between sensor and processor, and plug and play in processor is possible. Also, Intelligence of sensor was possible because sensor includes transducer electronic data sheet (TEDS). In IEEE 1451 standards, IEEE 1451.4 is suitable standard in single sensor, and IEEE 1451.2 is suitable standard in multi-sensors (array sensor). In this paper, apply IEEE 1451 to electronic tongue system. In the case of electronic tongue system, because array sensor is used, it is that complex and difficult to apply IEEE 1451.4 that is standard for single sensor. In this paper, apply IEEE 1451.2 for array sensor to design of electronic tongue system. Communication interface method of IEEE 1451.2 for electronic tongue system is presented, and implemented TEDS of electronic tongue system.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.202-204
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• 1995

An acoustic sensor using PVDF film is proposed in this paper. And its properties, such as sensitivity level, identification of sound source frequencies. and directivity, were experimented. Sensitivity level measured at the distance of 1[m] was limited in the range of ${\pm}$10dB. Adjacent three frequencies were also tested to identify the frequency of sound sources. In the range of audible frequencies, it could distinguish the frequencies of a complex sound. In addition, it was found that the sensor outputs were maximum in the coincided direction with a source, when directivity was experimented with three sound sources and FFT. The proposed PVDF film sensor has good characteristics of directivity and identifying ability as an acoustic sensor.

• 한국소음진동공학회논문집
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• 제19권4호
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• pp.418-424
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• 2009

This work is the attempt to give qualitative explanations to complex magnetic phenomena which are observed in the previously proposed magnetostrictive sensor capable of ultrasonic waves and rotational speed measurement. The law of approach is adopted as analysis tool in order to account for some extraordinary output patterns and proved to be effective. The distance between the anhysteretic curve current magnetic state and the variation of anhysteretic curve by stress mainly determine the sensor output shapes and their uniqueness. It is also experimentally verified that the precisely determined bias magnetic field strength can not only remove the unusual output parts but also maximize its sensitivity.

• 대한산업공학회지
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• 제23권1호
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• pp.95-113
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• 1997

This paper outlines a framework for a diagnosis of a complex system with uncertain information. Sensor validation ploys a vital role in the ability of the overall system to correctly determine the state of a system monitored by imperfect sensors. Here, emphases are put on the heuristic technology and post-processor for reasoning. Heuristic Sensor Validation (HSV) exploits deeper knowledge about parameter interaction within the plant to cull sensor faults from the data stream. Finally the modified probability distributions and validated data are used as input to the reasoning scheme which is the runtime version of the influence diagram. The output of the influence diagram is a diagnostic mapping from the symptoms or sensor readings to a determination of likely failure modes. Once likely failure modes are identified, a detailed diagnostic knowledge base suggests corrective actions to improve performance. This framework for a diagnostic expert system with sensor validation and reasoning under uncertainty applies in $HEATXPRT^{TM}$ a data-driven on-line expert system for diagnosing heat rate degradation problems in fossil power plants [1].