• 센서학회지
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• 제31권6호
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• pp.428-432
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• 2022

In this study, we describe the improvement of the resolution of a paper-based sensor by fabricating a high-concentration ninhydrin part using a low-temperature drying method to detect proline with high resolution. In the conventional paper-based sensor for detecting proline, the ninhydrin part is fabricated at room temperature, and in this process, the ninhydrin solution spreads around the ninhydrin part. Therefore, the concentration of the ninhydrin part becomes lower than that of the applied solution, lowering the resolution of the sensor. The proposed paper-based sensor better improved the sensitivity of the sensor compared to the existing sensor by fabricating a high-concentration ninhydrin part through drying the ninhydrin solution using a low-temperature drying method. Owing to the experiment, the intensity of the green color of the paper-based sensor with the integrated ninhydrin part fabricated at 10 ℃ is approximately 20% lower than the paper-based sensor with an integrated ninhydrin part fabricated at room temperature, indicating better sensor resolution. Therefore, the paper-based sensor with an integrated ninhydrin part fabricated at a high concentration could be useful for diagnosing drought.

• International Journal of Internet, Broadcasting and Communication
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• 제14권4호
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• pp.96-103
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• 2022

In this paper, we define EMRA-based USN metadata to describe sensor device, sensor node, and sensor network information at the application level. And the proposed method for effectively storing and retrieving USN metadata based on EMRA uses agent technology. As the sensor metadata proposed in this paper is based on SensorML, interoperability can be maintained in the USN environment, and the metadata management system can be directly utilized for metadata management in USN middleware or applications.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.799-802
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• 2005

In this paper, we analyses of Key Management Protocol for Wireless Sensor Networks in Wireless Sensor Networks. Wireless sensor networks have a wide spectrum of civil military application that call for security, target surveillance in hostile environments. Typical sensors possess limited computation, energy, and memory resources; therefore the use of vastly resource consuming security mechanism is not possible. In this paper, we propose a cryptography key management protocol, which is based on identity based symmetric keying.

• Journal of Information Processing Systems
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• 제14권2호
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• pp.396-417
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• 2018

GR-tree and query aggregation techniques have been proposed for spatial query processing in conventional spatial query processing for wireless sensor networks. Although these spatial query processing techniques consider spatial query optimization, time query optimization is not taken into consideration. The index reorganization cost and communication cost for the parent sensor nodes increase the energy consumption that is required to ensure the most efficient operation in the wireless sensor node. This paper proposes itinerary-based R-tree (IR-tree) for more efficient spatial-temporal query processing in wireless sensor networks. This paper analyzes the performance of previous studies and IR-tree, which are the conventional spatial query processing techniques, with regard to the accuracy, energy consumption, and query processing time of the query results using the wireless sensor data with Uniform, Gauss, and Skew distributions. This paper proves the superiority of the proposed IR-tree-based space-time indexing.

• Journal of the Optical Society of Korea
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• 제3권2호
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• pp.69-73
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• 1999

This paper demonstrated the performance of a palladium wire hydrogen sensor based on a fiber Bragg grating as a means of developing a quasi-distributed hydrogen sensor network capable of operating at cryogenic temperatures. The new approach employing a fiber Bragg grating based palladium hydrogen sensor described in this study is advantageous over other traditional hydrogen sensors because of the multiplexing capability of fiber Bragg gratings. The sensitivity of the hydrogen sensor at room temperature is approximately 2.5 times that of the hydrogen sensor at cryogenic temperatures.

• 컴퓨터교육학회논문지
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• 제15권6호
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• pp.75-82
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• 2012

센서 레지스트리 시스템은 이기종 센서 네트워크에 독립적으로 센서 데이터 의미를 해석하고 처리하기 위해 제안되었다. 그러나 기존 센서 레지스트리 시스템 구조는 정적 처리 방법을 제공한다. 즉, 이용할 데이터 영역을 고려하지 않고 불필요한 연산을 수행함으로써 전체적인 처리 성능을 저하시킨다. 이 논문에서는 기존 센서 레지스트리 시스템 구조의 문제점을 해결하기 위해 센서 메타데이터 영역화와 재사용성에 기반한 성능 개선 모델을 제안한다. 제안 모델은 센서 레지스트리 시스템에서 모바일 디바이스로 전송되는 센서 메타데이터의 영역을 상황 맞게 결정할 수 있는 기능을 제공한다. 또한 센서 메타데이터의 재사용성을 지원함으로써 전체적인 성능을 향상시킨다. 마지막으로 이 논문에서는 성능 비교 평가를 통해 제안 모델의 장점을 보인다.

• Journal of Mechanical Science and Technology
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• 제20권4호
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• pp.505-512
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• 2006

This paper presents an integrated multifunctional sensor based on MEMS technology, which can be used or embedded in mobile devices for environmental monitoring. An absolute pressure sensor, a temperature sensor and a humidity sensor are integrated in one silicon chip of which the size is $5mm\times5mm$. The pressure sensor uses a bulk-micromachined diaphragm structure with the piezoresistors. For temperature sensing, a silicon temperature sensor based on the spreading-resistance principle is designed and fabricated. The humidity sensor is a capacitive humidity sensor which has the polyimide film and interdigitated capacitance electrodes. The different piezoresistive orientation is used for the pressure and temperature sensor to avoid the interference between sensors. Each sensor shows good sensor characteristics except for the humidity sensor. However, the linearity and hysteresis of the humidity sensor can be improved by selecting the proper polymer materials and structures.

• Smart Structures and Systems
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• 제6권5_6호
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• pp.525-543
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• 2010

Testing and validation processes are critical tasks in developing a new hardware platform based on a new technology. This paper describes a series of experiments to evaluate the performance of a newly developed MEMS-based wireless sensor node as part of a wireless sensor network (WSN). The sensor node consists of a sensor board with four accelerometers, a thermometer and filtering and digitization units, and a MICAz mote for control, local computation and communication. The experiments include calibration and linearity tests for all sensor channels on the sensor boards, dynamic range tests to evaluate their performance when subjected to varying excitation, noise characteristic tests to quantify the noise floor of the sensor board, and temperature tests to study the behavior of the sensors under changing temperature profiles. The paper also describes a large-scale deployment of the WSN on a long-span suspension bridge, which lasted over three months and continuously collected ambient vibration and temperature data on the bridge. Statistical modal properties of a bridge tower are presented and compared with similar estimates from a previous deployment of sensors on the bridge and finite element models.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권10호
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• pp.3554-3570
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• 2021

With the rapid development of the Chinese water project, the safety monitoring of dams is urgently needed. Many drawbacks exist in dams, such as high monitoring costs, a limited equipment service life, long-term monitoring difficulties. MEMS sensors have the advantages of low cost, high precision, easy installation, and simplicity, so they have broad application prospects in engineering measurements. This paper designs intelligent monitoring based on the collaborative measurement of dual MEMS sensors. The system first determines the endpoint coordinates of the sensor array by the coordinate transformation relationship in the monitoring system and then obtains the dam settlement according to the endpoint coordinates. Next, this paper proposes a dual-MEMS sensor collaborative measurement algorithm that builds a mathematical model of the dual-sensor measurement. The monitoring system realizes mutual compensation between sensor measurement data by calculating the motion constraint matrix between the two sensors. Compared with the single-sensor measurement, the dual-sensor measurement algorithm is more accurate and can improve the reliability of long-term monitoring data. Finally, the experimental results show that the dam subsidence monitoring system proposed in this paper fully meets the engineering monitoring accuracy needs, and the dual-sensor collaborative measurement system is more stable than the single-sensor monitoring system.

• 대한전기학회논문지
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• 제39권4호
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• pp.386-392
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• 1990

This paper discribes a sonar-based certainty grid, the probabilistic representation of the uncertain and incomplete sensor knowledge, for autonomous mobile robot navigation. We use sonar sensor range data to build a map of the robot's surroundings. This range data provides information about the location of the objects which may exist in front of the sensor. From this information, we can compute the probability of being occupied and that of being empty for each cell. In this paper, a new method using Bayesian formula is introduced, which enables us to overcome some difficulties of the Ad-Hoc formula that has been the only way of updating the grids. This new formula can be applied to other kinds of sensors as well as sonar sensor. The validity of this formula in the real world is verified through simulation and experiment. This paper also shows that a wide angle sensor such as sonar sensor can be used effectively to identify the empty area, and the simultaneous use of multiple sensors and fusion in a certainty grid can improve the quality of the map.