• 센서학회지
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• 제27권3호
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• pp.156-159
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• 2018

We developed a glucose sensor using glucose dehydrogenase flavin adenine dinucleotide (GDH-FAD). The structure of the three-layer glucose sensor was simplified, in which a single-layer design was used to lower the unit cost, and GDH-FAD was used to increase the measurement reliability. GDH-FAD has less impact on the 20 interfering substances that affect blood glucose measurement, such as galactose and maltose compared to glucose oxidase (GOD), and is not affected by the oxygen saturation; therefore, it is possible to measure both arterial or venous blood and thus less susceptibility to hematocrit. In this study, we developed a single-layer glucose sensor strip with low hematocrit effect using the GDH-FAD enzyme, and measured and evaluated the performance.

• 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.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.772-777
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• 2008

Recent development of fiber optic sensors and wireless sensor technology, made structural health monitoring of railway structures cost effective. In this paper, a micro bending fiber optic rail pad sensors are evaluated for train axle force measurement. In order to assess the usability of FBG fiber optic sensors for short-term bridge measurement, the FBG sensors and conventional strain gauges are installed at the same points and the strain results are compared. Also the impact factors are calculated using the FBG strain responses and the results are compared with the conventional sensor responses. A running KTX train was instrumented with wireless sensor system to measure the vibration characteristics and the results are compared with conventional wire sensor system.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.310-316
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• 2017

The robot proximity and tactile sensors can be categorized into two groups: grip sensors and safety sensors. They have different performance requirements. The safety sensor should have long proximity range and fast response in order to secure enough response time before colliding with ambient objects. As for the tactile sensing function, the safety sensor need to be fast and compliant to mitigate the impact from a collision. In order to meet these requirements, we proposed and demonstrated a compliant integrated safety sensor suitable to human-friendly robots. An ultrasonic proximity sensor and a piezoelectric tactile sensor made of PVDF films have been integrated in a compliant PDMS structure. The implemented sensor demonstrated the maximum proximity range of 35 cm. The directional tolerance for 30 cm detection range was about ${\pm}15^{\circ}$ from the normal axis. The integrated PVDF tactile sensor was able to detect various impacts of up to 20 N in a controlled experimental setup.

• 비파괴검사학회지
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• 제32권1호
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• pp.47-55
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• 2012

본 논문에서는 단일 센서와 시간역전 원리를 이용하여 간단한 판에서 충격 위치를 결정할 수 있는 탐상법을 다루었다. 수치적인 시뮬레이션과 실험을 통하여 시간역전에 의한 충격위치와 그 주변에서 신호의 집속효과를 관찰하고, 충격위치 결정에 영향을 미칠 수 있는 인자들(가진력의 크기, 신호의 기록시간)에 대해 살펴보았다. 이러한 결과를 기초로 두 가지 다른 충격위치에 대한 실험을 수행하고 그 결과를 가시화하였으며, 실제 충격위치를 정확하게 결정할 수 있음을 확인하였다. 여기서 제안한 방법의 특징은 단일센서를 사용하는 것과 시험체의 형상과 물성을 몰라도 된다는 점이다. 또한 판에서와 같이 분산성의 다중모드 파동이 발생하는 경우에도 특정 모드나 주파수에 의존할 필요가 없다. 따라서 기존의 충격위치 결정법에 비해 많은 장점을 지니고 있다.

• 제어로봇시스템학회논문지
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• 제12권7호
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• pp.650-657
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• 2006

The LPMS (Loose Part Monitoring Systems) are used widely for detecting the impact position in the nuclear reactor. There are some major methods to detect impact position in LPMS such as the triangular method, the rectangular method, the circular intersection method and so on. The time difference of these methods are calculated using S0-mode and A0-mode waves of each sensor. In this paper, we propose a method to detect impact position using the enveloped waves of acquired signals. The result of this paper show that the position detecting accuracy and reducing the processing time are proposed method is improved than traditional methods.

• 연구논문집
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• 통권32호
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• pp.45-53
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• 2002

Hydraulic breaker attached excavator generally used for the destroying and disassembling of buildings, crashing road pavement, breaking rocks at quarry and etc. The developed breaker are determined their own destructive force and number of impact by the input hydraulic flow rate and pressure than the operating conditions, In this study, the characteristics of pressure variation in closed vessel is invested for testing the impact energy of hydraulic breaker. To test the impact energy, the test system is designed as a mechanism consisted with a hydraulic cylinder, main base, pressure sensor, LVDT, data acquisition system and etc.. The developed test system is applied to measure the impact energy for hydraulic breaker. The proposed testing method could be applied for conventional impact test and the control system evaluation for hydraulic breakers.

• 드라이브 ㆍ 컨트롤
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• 제16권2호
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• pp.1-7
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• 2019

Jaw crusher is a device that breaks rock collected from mines or quarries to produce aggregates of the size desired by user. A representative method for measuring load is to measure them by attaching force sensors directly to the part where the load is generated. However, the direct method has many limitations such as high-impact loads generation in equipment or space constraints, sensor capacities and costs. Therefore, Transfer Path Analysis (TPA) was used to indirectly measure impact loads by attaching acceleration sensors. In this study, both direct and TPA methods were used to measure the impact load of Jaw crusher. This study finally quantifies the impact of the load generated by the Jaw crusher using direct method and TPA method, and comparing the impact load measured calculated the derive the error rate.

• Journal of Information Processing Systems
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• 제12권2호
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• pp.275-294
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• 2016

A primary task in wireless sensor networks (WSNs) is data collection. The main objective of this task is to collect sensor readings from sensor fields at predetermined sinks using routing protocols without conducting network processing at intermediate nodes, which have been proved as being inefficient in many research studies using a static sink. The major drawback is that sensor nodes near a data sink are prone to dissipate more energy power than those far away due to their role as relay nodes. Recently, novel WSN architectures based on mobile sinks and mobile relay nodes, which are able to move inside the region of a deployed WSN, which has been developed in most research works related to mobile WSN mainly exploit mobility to reduce and balance energy consumption to enhance communication reliability among sensor nodes. Our main purpose in this paper is to propose a solution to the problem of deploying mobile data collectors for alleviating the high traffic load and resulting bottleneck in a sink's vicinity, which are caused by static approaches. For this reason, several WSNs based on mobile elements have been proposed. We studied two key issues in WSN mobility: the impact of the mobile element (sink or relay nodes) and the impact of the mobility model on WSN based on its performance expressed in terms of energy efficiency and reliability. We conducted an extensive set of simulation experiments. The results obtained reveal that the collection approach based on relay nodes and the mobility model based on stochastic perform better.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권1호
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• pp.241-269
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• 2012

Wireless networks composed of multimedia-enabled resource-constrained sensor nodes have enriched a large set of monitoring sensing applications. In such communication scenario, however, new challenges in data transmission and energy-efficiency have arisen due to the stringent requirements of those sensor networks. Generally, congested nodes may deplete the energy of the active congested paths toward the sink and incur in undesired communication delay and packet dropping, while bit errors during transmission may negatively impact the end-to-end quality of the received data. Many approaches have been proposed to face congestion and provide reliable communications in wireless sensor networks, usually employing some transport protocol that address one or both of these issues. Nevertheless, due to the unique characteristics of multimedia-based wireless sensor networks, notably minimum bandwidth demand, bounded delay and reduced energy consumption requirement, communication protocols from traditional scalar wireless sensor networks are not suitable for multimedia sensor networks. In the last decade, such requirements have fostered research in adapting existing protocols or proposing new protocols from scratch. We survey the state of the art of transport protocols for wireless multimedia sensor networks, addressing the recent developments and proposed strategies for congestion control and loss recovery. Future research directions are also discussed, outlining the remaining challenges and promising investigation areas.