• 센서학회지
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• 제17권4호
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• pp.281-288
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• 2008

Polyacrylonitrile(PAN)/metal oxide(MO) nanocomposite mats with a thickness of 0.12 mm were electrospun by adding 0 to 10 wt% of MO nanoparticles ($Fe_2O_3$, ZnO, $SnO_2$, $Sb_2O_3-SnO_2$) into PAN. Pt electrode was patterned on $Al_2O_3$ substrate by DC sputtering and then the PAN(/MO) mats on the Pt patterned $Al_2O_3$ were electrically wired to investigate the $CO_2$ gas sensing properties. As the MO content rose, the fiber diameter decreased due to the presence of lumps caused by the presence of MOs in the fiber. The PAN/2% ZnO mat revealed a faster response time of 93 s and a relatively short recovery of 54 s with a ${\Delta}R$ of 0.031 M${\Omega}$ at a $CO_2$ concentration of 200 ppm. The difference in sensitivity was not observed significantly for the PAN/MO fiber mats in the $CO_2$ concentration range of 100 to 500 ppm. It can be concluded that an appropriate amount of MO nanoparticles in the PAN backbone leads to improvement of the $CO_2$ gas sensing properties.

• 센서학회지
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• 제12권1호
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• pp.24-33
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• 2003

This research is about a comfort sensing system for human environmental monitoring using a one-bodied humidity and temperature sensor and an air flow sensor. The thermal comfort that a human being feels in indoor environment has been known to be influenced mostly by six parameters, i.e. air temperature, radiation, air flow, humidity, activity level and clothing thermal resistance. Considering an environmental monitoring, we have designed and fabricated a one-bodied humidity and temperature sensor and an air flow sensor that detect air relative humidity, temperature and air flow in human environment using surface micromachining technologies. Micro-controller calculates a PMV (predicted mean vote) and CSV (comfort sensing vote) with sensing signals and display a PMV on LCD (liquid crystal display) for human comfort on indoor climate. Our work has demonstrated that a comfort sensing system can provide an effective means of measuring and monitoring the indoor comfort sensing index of a human being. Experimental results with simulated environment clearly suggest that our comfort sensing system can be used in many applications such as air conditioning system, feedback controlling in automobile, home and hospital etc..

• 한국작물학회:학술대회논문집
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• 한국작물학회 2005년도 국제학술회의
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• pp.22-46
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• 2005

Spatial and timely information on crop and filed conditions is one of the most important basics for rational and efficient planning and management in agriculture. Remote sensing, GIS, and modeling are powerful tools for such applications. This paper presents an overview of the state of the art in remote sensing of crop and field conditions with some case studies. It is also shown that a synergistic linkage between process-based models and remote sensing signatures enables us to estimate the multiple crop/ecosystem variables at a dynamic mode. Remotely sensed information can greatly reduce the uncertainty of simulation models by compensating for insufficient availability of data or parameters. This synergistic approach allows the effective use of infrequent and multi-source remote sensing data for estimating important ecosystem variables such as biomass growth and ecosystem $CO_2$ flux. This paper also shows a geo-spatial information system that enables us to integrate, search, extract, process, transform, and calculate any part of the data based on ID#, attributes, and/or by river-basin boundary, administrative boundary, or boundaries of arbitrary shape/size all over Japan. A case study using the system demonstrates that the nitrogen load from fertilizer was closely related to nitrate concentration of groundwater. The combined use of remote sensing, GIS and modeling would have great potential for various agro-ecosystem applications.

• 한국재료학회지
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• 제25권8호
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• pp.423-428
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• 2015

Impedancemetric $NO_x$ (NO and $NO_2$) gas sensors were designed with a stacked-layer structure and fabricated using $LaCr_xCo_{1-x}O_3$ (x = 0, 0.2, 0.5, 0.8 and 1) as the receptor material and $Li_{1.3}Al_{0.3}Ti_{1.7}(PO_4)_3$ plates as the solid-electrolyte transducer material. The $LaCr_xCo_{1-x}O_3$ layers were prepared with a polymeric precursor method that used ethylene glycol as the solvent, acetyl acetone as the chelating agent, and polyvinylpyrrolidone as the polymer additive. The effects of the Co concentration on the structural, morphological, and $NO_x$ sensing properties of the $LaCr_xCo_{1-x}O_3$ powders were investigated with powder X-ray diffraction, field emission scanning electron microscopy, and its response to 20~250 ppm of $NO_x$ at $400^{\circ}C$ (for 1 kHz and 0.5 V), respectively. When the as-prepared precursors were calcined at $700^{\circ}C$, only a single phase was detected, which corresponded to a perovskite-type structure. The XRD results showed that as the Co concentration of the $LaCr_xCo_{1-x}O_3$powders increased, the crystal structure was transformed from an orthorhombic phase to a rhombohedral phase. Moreover, the $LaCr_xCo_{1-x}O_3$ powders with $0{\leq}x<0.8$ had a rhombohedral symmetry. The size of the particles in the $LaCr_xCo_{1-x}O_3$powders increased from 0.1 to $0.5{\mu}m$ as the Co concentration increased. The sensing performance of the stack-structured $LaCr_xCo_{1-x}O_3/Li_{1.3}Al_{0.3}Ti_{1.7}(PO_4)_3$ sensors was found to divide the impedance component between the resistance and capacitance. The response of these sensors to NO gas was more sensitive than that to $NO_2$ gas. Compared to other impedancemetric sensors, the $LaCr_{0.8}Co_{0.2}O_3/Li_{1.3}Al_{0.3}Ti_{1.7}(PO_4)_3$ sensor exhibited good reversibility and reliable sensingresponse properties for $NO_x$ gases.

• 대한원격탐사학회지
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• 제38권3호
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• pp.237-250
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• 2022

본 연구에서는 딥러닝 기반 다중 객체 추적 모델을 활용하여 수중드론으로 촬영된 영상으로부터 특정 해역의 조식동물 현존량을 추정하는 방법을 제안한다. 수중드론 영상 내에 포함된 조식동물을 클래스 별로 탐지하기 위해 YOLOv5 (You Only Look Once version 5)를 활용하였으며, 개체수 집계를 위해 DeepSORT (Deep Simple Online and real-time tracking)를 활용하였다. GPU 가속기를 활용할 수 있는 워크스테이션 환경에서 두 모델의 성능 평가를 수행하였으며, YOLOv5 모델은 평균 0.9 이상의 모델의 정확도(mean Average Precision, mAP)를 보였으며, YOLOv5s 모델과 DeepSORT 알고리즘을 활용하였을 때, 4 k 해상도 기준 약 59 fps의 속도를 보이는 것을 확인하였다. 실해역 적용 결과 약 28%의 과대 추정하는 경향이 있었으나 객체 탐지 모델만 활용하여 현존량을 추정하는 것과 비교했을 때 오차 수준이 낮은 것을 확인하였다. 초점을 상실한 프레임이 연속해서 발생할 때와 수중드론의 조사 방향이 급격히 전환되는 환경에서의 정확도 향상을 위한 후속 연구가 필요하지만 해당 문제에 대한 개선이 이루어진다면, 추후 조식동물 구제 사업 및 모니터링 분야의 의사결정 지원자료 생산에 활용될 수 있을 것으로 판단된다.

• 한국재료학회지
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• 제12권4호
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• pp.269-273
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• 2002

The NASICON solid electrolyte films, $Na_{1+x}Zr_2Si_xP_{3-x}O_{12}$(1.5< x < 2.3), was prepared from ceramic slurry by modified doctor-blade process. The NASICON solid electrolyte and fabricated sensors, Pt-electrode/NASICON/Carbonate$(Na_2CO_3-K_2CO_3CaCO_3\; system)$ electrode, were investigated to measure phase, microstructure and e.m.f variation for sensing $CO_2$ concentration. The uniform grain size of $2-4{\mu}m$ and major phase of sodium zirconium silicon phosphate phase, $Na_{1+x}Zr_2Si_xP_{3-x}O_{12}$was identified with X-ray diffraction patterns and scanning electron microscopy, respectively. The Nernst's slope of 84 mV/decade for $CO_2$ concentration from 500 to 8000 ppm was obtained at operating temperature of $400^{\circ}C$.

• 센서학회지
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• 제8권6호
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• pp.454-460
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• 1999

스크린 프린팅 법으로 알루미나 기판 위에 $LaCoO_3$ 후막을 형성하여 열처리 온도에 따른 $C_4H_{10}$, $NH_3$, $NO$ 및 CO 가스에 대한 감도를 조사하였다. X-선 분석과 SEM 사진을 통해 $LaCoO_3$ 후막의 구조적 특성을 관찰하였다. 제조한 센서는 $C_4H_{10}$, $NH_3$ NO 가스에 대한 감도보다 CO 가스에 대한 감도가 우수하였다. 후막의 최적 열처리온도와 동작온도는 각각 $800^{\circ}C$ 및 $150^{\circ}C$였다. CO 가스 500ppm과 1250ppm에 대한 감도는 각각 72%와 95%였다.

• 한국산업융합학회 논문집
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• 제20권4호
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• pp.299-305
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• 2017

This study proposes a new technique to design and control of robot hand gripper for assembling and disassembling of a machine parts. The motion equation describing dynamics of the manipulators and object together with geometric constraint is formulated by Lagrange-Euler's equation. And the problems of controlling both the grasping force and the rotation angle of the grasped object under the constraints are analyzed. The effect of geometric constraints and a method of computer simulation for overall system is verified. Finally, it is illustrated that even in case of there exists a sensory feedback from sensing data of the rotational angle of the object to command inputs control of joint and this feedback connection from sensing data to control grasping of machinery parts.

• 대한전자공학회논문지
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• 제26권11호
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• pp.1691-1698
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• 1989

Gas sensing effects produced by adsorptive reaction between specimen surface and gases are expected to be influenced greatly by the state of the speimen surface. In this study, Co1-xMgxO ceramics oxygen sensors were prepared by pressing at 0.3-1.5ton/cm\ulcornerwith or without binder, intending to change porosity and average grain size on the surface purposely. The composition ratio of CoO to MgO was fixed at 1:1(mol.%). Microstructure of prepared Co0.5Mg0.5O ceramics were observed, the electrical properties and the sensitivity characteristics for oxygen gas were investigated in the device temperature range of 700-1000\ulcorner and for oxygen partical pressure range of 1-10**-4 atm. Temperature dependence of the resistivity of the specimen showed NTC behavior, average grain size increased and porosity decreased with increasing compaction pressure. The slope of the resistivity of the specimen on the oxygen partial pressure decreased with increasing average grain size and with decreasing porosity. Particularly, specimen pressed by 0.3 and 0.5 ton/cm\ulcornershowed the highest sensitivity to oxygen gas.

• 한국전기전자재료학회논문지
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• 제11권4호
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• pp.288-292
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• 1998

In this paper, we fabricated $SnO_2$ composite ceramics doped with 0~20mol% $SnO_2$ of bulk type to investigate the CO and $H_2$ gas sensitivity in various composition, temperature, and concentration of CO and $H_2$ gas. At the temperature range from $100^{\circ}C\sim425^{\circ}C$, the measured 1000ppm and 250ppm CO gas sensitivities of $SiO_2-SnO_2$composite ceramics were about 1.0~7.6 and 1.0~5.6, respectively. These values were about 1.0~1.5 times larger than pure $SnO_2$. The maximum 1000ppm CO gas sensitivity of $SiO_2-SnO_2$composites were measured around $325^{\circ}C$. At the temperature range from $270^{\circ}C\sim380^{\circ}C$, the 1000ppm and 500ppm $H_2$gas sensitivities of $SiO_2-SnO_2$ composites were about 2.9~21.2 and 2.1~11.3, respectively. Also the maximum 1000, 500 ppm $H_2$ gas sensitivities of samples were measured around.