• Journal of Information Processing Systems
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• 제1권1호
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• pp.49-54
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• 2005

With the recent advances in Micro Electro Mechanical System (MEMS) technology, low cost and low power consumption wireless micro sensor nodes have become available. However, energy-efficient routing is one of the most important key technologies in wireless sensor networks as sensor nodes are highly energy-constrained. Therefore, many researchers have proposed routing protocols for sensor networks, especially cluster-based routing protocols, which have many advantages such as reduced control messages, bandwidth re-usability, and improved power control. Some protocols use information on the locations of sensor nodes to construct clusters efficiently. However, it is rare that all sensor nodes know their positions. In this article, we propose another cluster-based routing protocol for sensor networks. This protocol does not use information concerning the locations of sensor nodes, but uses the remaining energy of sensor networks and the desirable number of cluster heads according to the circumstances of the sensor networks. From performance simulation, we found that the proposed protocol shows better performance than the low-energy adaptive clustering hierarchy (LEACH).

• 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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1097-1102
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• 2007

This paper describes the development of 6-axis force/moment sensor for an intelligent robot's foot. In order to walk on uneven terrain safely, the foot should perceive the applied forces Fx, Fy, Fz and moments Mx, My, Mz to itself. The applied forces and moments should be measured from a 6-axis force/moment sensor attached to a humanoid robot's foot(ankle). They in the published paper already have some disadvantage in the size of the sensor, the rated output and so on. The rated output of each component sensor (6-axis force/moment sensor) is very important to design the 6-axis force/moment sensor for precision measurement. Therefore, each sensor should be designed to be gotten similar the rated output under each rated load. So, the sensing elements of the 6-axis force/moment sensor should get lots of design variables. Also, the size of 6- axis force/moment sensor is very important for mounting to robot's foot. In this paper, a 6-axis force/moment sensor for perceiving forces and moments in a humanoid robot's foot was developed using many PPBs (parallel plate-beams). The structure of the sensor was newly modeled, and the sensing elements (plate-beams) of the sensor were designed using FEM (Finite Element Method) analysis. Then, the 6-axis force/moment sensor was fabricated by attaching strain-gages on the sensing elements, and the characteristic test of the developed sensor was carried out. The rated outputs from FEM analysis agree well with that from the characteristic test.

• 정보과학회 논문지
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• 제42권2호
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• pp.255-263
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• 2015

센서 레지스트리 시스템은 이기종 센서 네트워크 환경에서 센서 데이터의 즉시적 활용 및 끊김 없는 해석을 위해 개발되었다. 그러나 기존 센서 레지스트리 시스템은 불안정한 네트워크 상황에서 센서 데이터 해석을 위한 정보를 제공하지 못하며, 이로 인해 센서 데이터의 손실, 처리 결과의 부정확성, 서비스 품질 저하 등의 문제를 야기한다. 이 논문에서는 소프트웨어 관점에서 이러한 문제점을 해결할 수 있는 방안을 제시한다. 사용자의 이동 경로를 예측하여 사전에 센서 정보를 이동 단말기에 제공함으로써 불완전한 네트워크 접속 시점에 안정적으로 센서 정보를 활용할 수 있는 확장된 센서 레지스트리 시스템을 제안하고 실험 및 평가 결과를 보인다. 이 논문에서 제안한 확장된 센서 레지스트리 시스템은 센서 정보의 안정적 활용성 증가와 더불어 센서 기반 서비스 품질을 향상시킨다.

• 한국군사과학기술학회지
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• 제13권6호
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• pp.1006-1012
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• 2010

For the autonomous navigation of an unmanned ground vehicle in the rough terrain and combat, the dust environment should necessarily be overcome. Therefore, we propose a robust obstacle detection methodology using laser range sensor and radar. Laser range sensor has a good angle and distance accuracy, however, it has a weakness in the dust environment. On the other hand, radar has not better the angle and distance accuracy than laser range sensor, it has a robustness in the dust environment. Using these characteristics of laser range sensor and radar, we use laser range sensor as a main sensor for normal times and radar as a assist sensor for the dust environment. For fusion of laser range sensor and radar information, the angle and distance data of the laser range sensor and radar are separately transformed to the angle and distance data of virtual range sensor which is located in the center of the vehicle. Through distance comparison of laser range sensor and radar in the same angle, the distance data of a fused virtual range sensor are changed to the distance data of the laser range sensor, if the distance of laser range sensor and radar are similar. In the other case, the distance data of the fused virtual range sensor are changed to the distance data of the radar. The suggested methodology is verified by real experiment.

• 한국컴퓨터정보학회논문지
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• 제18권8호
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• pp.105-111
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• 2013

본 논문에서는 스마트 센서 응용 소프트웨어를 테스팅하기 위한 효율적인 방법인 가상 센서 시스템을 제안한다. 센서 응용 소프트웨어를 테스트하는 보편적인 방법은 테스트 보드에 센서를 직접 연결시켜 테스팅 환경의 센서 측정값으로 응용소프트웨어를 테스팅 하는 것이다. 센서 측정값을 입력으로 센서 응용 소프트웨어를 테스팅함으로 발생하는 문제는 테스트 데이터가 제한적이라는 것이다. 즉, 테스트 데이터가 센서로부터 생성되기 때문에 소프트웨어 테스터가 테스트 데이터를 조절하지 못하는 문제가 있다. 이러한 문제를 해결하기 위해 가상센서 시스템을 제안한다. 가상 센서 시스템은 소프트웨어 테스터가 센서의 측정값을 조절할 수 있게 한다. 가상 센서 시스템에서 센서 선택, 센서 특성화, 출력 패턴 정의의 세 단계를 통해 가상 센서를 정의한다. 가상 센서 시스템을 통해 조절 가능한 센서 측정값을 사용함으로써 센서 응용 소프트웨어에 대한 효율적인 테스트가 가능하다. 본 연구의 유용성을 보이기 위해 가상 센서 시스템을 안드로이드 앱의 센서 프로그램에 적용해 보고 실험 결과를 보인다.

• 한국전기전자재료학회논문지
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• 제28권6호
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• pp.403-407
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• 2015

Generally, MWCNT, with thermal, chemical and electrical superiority, is manufactured with CVD (chemical vapor deposition). Using MWCNT, it is comonly used as gas sensor of MOS-FET structure. In this study, in order to repeatedly detect gases, the author had to effectively eliminate gases absorbed in a MWCNT sensor. So as to eliminate gases absorbed in a MWCNT sensor, the sensor was applied heat of 423[K], and in order to observe how the applied heat was diffused within the sensor, the author interpreted the diffusion process of heat, using COMSOL interpretation program. In order to interpret the diffusion process of heat, the author progressed modeling with the structure of MWCNT gas sensor in 2-dimension, and defining heat transfer velocity($u={\Delta}T/{\Delta}x$), accorded to governing equation within the sensor, the author proposed heat transfer mechanism.

• 대한임베디드공학회논문지
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• 제2권3호
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• pp.138-144
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• 2007

Wireless Sensor Network(WSN) consists of a lot of light-weight sensor nodes with the capability of wireless communication. Studies have been done to improve stability and fault-tolerancy of WSN because the sensor nodes are basically vulnerable to the harsh environment. Specially, the time synchronization among sensor nodes becomes a challenging issue in WSN. All the local times should always keep the same with each other in the sensor field to perform data aggregation and energy-aware communication in WSN. In this paper, a new time synchronization technique is proposed to operate efficiently irrespective of the number of sensor nodes and the number of hops needed to cover all sensor nodes for synchronization. Simulation results show that the proposed technique has the lowest amount of packet traffic among the several time synchronization techniques.

• 센서학회지
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• 제15권3호
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• pp.205-210
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• 2006

Hydrophobic polymer [ex. Poly(vinylidenfluoride)] layer was coated on polyaniline (PANi) sensor to reduce the contamination humidity. The differences in sensitivity to methanol gas detection in various humidity condition between pure-PANi sensor and sensor coated with poly(vinylidenfluoride) polymer (PVDF) (coated-PANi sensor) were investigated. Considering the relation between the density of pore, which was coated on the layer of the PANi sensor, and sensitivity was investigated. To fabricate the porous PVDF layer on PANi sensor, poly(vinylalcohol) (PVA), which is water-soluble polymer, was used. Coated-PANi sensor was less affected by humidity compared with pure-PANi sensor. And higher density of pore on PVDF layer led to higher sensitivity.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.176-180
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• 2007

In this study, we deployed the cable tunnel inspection and monitoring system by wireless sensor network. It is shown that the wireless sensor network which is composed of sensor, wireless communication module, and gateway can be applied to cable tunnel monitoring system. Sensors considered herein are flame detection sensor, flood detection sensor, intruder detection sensor, and temperature sensor, etc. It is also found that the wireless sensor network can deliver sensing data reliably by wireless sensing technology. The gateway system that can transmit sensed data to server by CDMA is developed. Monitoring system is constructed by web service technology, and it is observed that this system can monitor the present state of tunnel without difficulties. The system provides an alternative to inspect and monitor the tunnel efficiently where the conventional wired system is infeasible.