• Title/Summary/Keyword: Sensitivity improvement

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Improved Sensitivity of a Glucose Sensor by Encapsulation of Free GOx in Conducting Polymer Micropillar Structure

  • Jung, Shin-Hwan;Lee, Young-Kwan;Son, Yong-Keun
    • Journal of Electrochemical Science and Technology
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    • v.2 no.2
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    • pp.124-129
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    • 2011
  • A simple process of fabricating micropillar structure and its influence upon enhancing electrochemical biosensor response were studied in this work. Conducting polymer PEDOT was used as a base material in formulating a composite with PVA. Micro porous PC membrane filter was used as a template for the micropillar of the composite on ITO electrode. This structure could provide plenty of encapsulating space for enzyme species. After dosing enzyme solution into this space, Nafion film tent was cast over the pillar structure to complete the micropillar cavity structure. In this way, the encapsulation of enzyme could be accomplished without any chemical modification. The amount of enzyme species was easily controllable by varying the concentration of the dosing solution. The more amount of enzyme is stored in the sensor, the higher the electrochemical response is produced. One more reason for the sensitivity improvement comes from the large surface area of the micropillar structure. Application of 0.7 V produced the best current response under the condition of pH 7.4. This biosensor showed linear response to the glucose in 0.1~1 mM range with the average sensitivity of $14.06{\mu}A/mMcm^2$. Detection limit was 0.01 mM based on S/N = 3.

IMAGE SIMULATIONS OF THE KVN AND EAST ASIA VLBI FACILITIES WITH A SiO MASER MODEL IMAGE (KVN과 동아시아 VLBI 관측시설을 이용한 SiO 메이저 모델이미지 모의실험)

  • Yi, Ji-Yun;Jung, Tae-Hyun
    • Publications of The Korean Astronomical Society
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    • v.25 no.1
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    • pp.15-21
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    • 2010
  • We report results of image simulations of the KVN and VLBI experiments of the KVN with several other East Asia VLBI facilities. To investigate their imaging capability a model-generated image of 7 mm SiO maser emission in Mira variables is used. The resulting simulations show that the joint VLBI experiments of the KVN with East Asia VLBI facilities can produce reasonably good images at 7 mm spectral line experiments. However, there are no apparent differences in peak flux densities and images themselves in the simulations among different combinations of these facilities. In addition, the simulated images of observations which include bigger antennas do not show any expected improvement to the image sensitivity. The small variations in the peak flux density and similar image sensitivity, irrespective of different antenna sizes or numbers of baselines used in the simulations, turn out due to a specific characteristic of the adopted model image. Test simulations using another SiO maser image from R Cas observations prove that the participation of bigger antennas in the VLBI experiments does improve image sensitivity. We confirm the need of additional longer baselines in the experiments of the East Asia VLBI facilities to study very compact maser clumps on sub-milliarcsecond scales.

A Robust MRAC-based Speed Estimation Method to Improve the Performance of Sensorless Induction Motor Drive System in Low Speed (저속영역에서 센서리스 벡터제어 유도전동기의 성능을 향상시키기 위한 MRAC 기반의 강인한 속도 추정 기법)

  • 박철우;권우현
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.1
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    • pp.37-46
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    • 2004
  • A novel rotor speed estimation method using model reference adaptive control(MRAC) is proposed to improve the performance of a sensorless vector controller. In the proposed method, the stator current is used as the model variable for estimating the speed. In conventional MRAC methods, the relation between the two model errors and the speed estimation error is unclear. In the proposed method, the stator current error is represented as a function of the first degree for the error value in the speed estimation. Therefore, the proposed method can produce a fast speed estimation. The robustness of the rotor flux-based MRAC, back EMF-based MRAC, and proposed MRAC is compared based on a sensitivity function about each error of stator resistance, rotor time constant, mutual inductance. Consequently, the proposed method is much more robust than the conventional methods as regards errors in the mutual inductance, stator resistance. Therefore, the proposed method offers a considerable improvement in the performance of a sensorless vector controller at a low speed. In addition, the superiority of the proposed method and the validity of sensitivity functions were verified by simulation and experiment.

A Meta-analysis of the Timed Up and Go test for Predicting Falls (낙상 위험 선별검사 Timed Up and Go test의 예측 타당도 메타분석)

  • Park, Seong-Hi;Lee, On-Seok
    • Quality Improvement in Health Care
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    • v.22 no.2
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    • pp.27-40
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    • 2016
  • Purpose: Globally, falls are a major public health problem. The study aimed to evaluate the predictive validity of the Timed Up and Go test (TUGT) as a screening tool for fall risk. Methods: An electronic search was performed Medline, EMBASE, CINAHL, Cochran Library, KoreaMed and the National Digital Science Library and other databases, using the following keywords: 'fall', 'fall risk assessment', 'fall screening', 'mobility scale', and 'risk assessment tool'. The QUADAS-II was applied to assess the internal validity of the diagnostic studies. Thirteen studies were analyzed using meta-analysis with MetaDisc 1.4. Results: The selected 13 studies reporting predictive validity of TUGT of fall risks were meta-analyzed with a sample size of 1004 with high methodological quality. Overall predictive validity of TGUT was as follows. The pooled sensitivity 0.72 (95% confidence interval [CI]: 0.67-0.77), pooled specificity 0.58 (95% CI: 0.54-0.63) and sROC AUC was 0.75 respectively. Heterogeneity among studies was a moderate level in sensitivity. Conclusion: The TGUT's predictive validity for fall risk is at a moderate level. Although there is a limit to interpret the results for heterogeneity between the literature, TGUT is an appropriate tool to apply to all patients at a potential risk of accidental fall in a hospital or long-term care facility.

Effect of Electron Irradiation on the Properties of GZO Thin Film and its Gas Sensor Application (전자빔 표면 조사에 따른 GZO 박막의 물성과 가스센서 응용 연구)

  • Kim, Dae-Il
    • Journal of the Korean Society for Heat Treatment
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    • v.24 no.3
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    • pp.140-143
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    • 2011
  • In this work, Ga doped ZnO (GZO) films were prepared by radio frequency (RF) magnetron sputtering without intentional substrate heating on glass substrate and then the effect of the intense electron irradiation on structural and electrical properties and the NOx gas sensitivity were investigated. Although as deposited GZO films showed a diffraction peak for ZnO (002) in the XRD pattern, GZO films that electron irradiated at electron energy of 900 eV showed the higher intense diffraction peaks than that of the as deposited GZO films. The electrical property of the films are also influenced with electron's energy. As deposited GZO films showed the three times higher resistivity than that of the films irradiated at 900 eV In addition, the sensitivity for NOx gas is also increased with electron irradiation energy and the film sensor showed the proportionally increased gas sensitivity with NOx concentration. This approach is promising in gaining improvement in the performance of thin film gas sensors used for the detection of hazard gas phase.

Extraction of Fall-Feature Parameters for Fall Detection System Using 3-Axial Acceleration Sensor Data (3축 가속도 센서 낙상 감지 시스템을 위한 낙상 특징 파라미터 추출)

  • Lim, DongHa;Park, ChulHo;Yu, YunSeop
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2013.10a
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    • pp.393-395
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    • 2013
  • In modern society, the elderly over 65 years old are increasing due to development of medical technology and improvement of their standard of living. Severe fall of the elderly can lead to death threats. To solve this problem, several algorithms and hardware systems for fall detection have been studied and developed. In this paper, a fall detection system using 3-axial acceleration sensor is presented. In the fall detection system, several types of fall-feature parameters are calculated and then the fall is determined by using them. Using this system, best sensitivity and specificity are 98.3% and 94.7%, respectively.

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A Study on Sensitivity to Temperature of Electricity Consumption in School Buildings (학교 건축물 전력소비의 기온감응도에 관한 연구)

  • Kim, Tae-Woo;Lee, Kang-Guk;Kim, Ho-Soon;Hong, Won-Hwa
    • Journal of the Korean Institute of Educational Facilities
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    • v.18 no.5
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    • pp.13-21
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    • 2011
  • In case of school buildings, energy consumption has been noticeably on the increase, along with the changes in outdoor temperature triggered by the improvement in national economic development and educational environments. Research on the characteristics of energy consumption in school buildings influenced by the changes in outdoor temperature is considered very significant in social aspects in that it will be fundamental to the suggestion of the alternatives, such as saving energy consumption in construction buildings and control of emitting carbon dioxide. In this regard, this study examined sensitivity to temperature of power consumption in school buildings, based on the changes of outdoor temperature for the past five years in the target buildings of elementary, middle and high schools and the amount of energy consumption. From the results, it has been believed that this study was very significant in terms of figuring out a quantitative, optimum level of energy consumption, maintenance of pleasant environments and functions, and the necessity of effective energy use and management in school buildings.

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A Study on the Sensitivity of Self-Powered Neutron Detectors(SPNDs) and a new Proposal

  • Lee, Wanno;Gyuseong Cho
    • Proceedings of the Korean Nuclear Society Conference
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    • 1997.05b
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    • pp.445-450
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    • 1997
  • Self-Powered Neutron Detectors(SPNDs) are currently used to estimate the power generation distribution and fuel burn-up in several nuclear power reactors in Korea. In this paper, Monte Carlo simulation is accomplished to calculate the escape probability of beta particle as a function of their birth position fur the typical geometry of rhodium-based SPNDs. Also, a simple numerical method calculates the initial generation rate of beta particles and the change of generation rate due to rhodium burn-up. Using the simulation and the numerical method, the burn-up profile of rhodium density and the neutron sensitivity are calculated as a function of burn-up time in the reactor. The sensitivity of the SPNDs decreases non-linearly due to the high absorption cross-section and the non-uniform burn-up of rhodium in the emitter rod. In addition, for improvement of some properties of rhodium-based SPNDs which are currently used, this paper presents a new material. The method used here can be applied to the analysis of other types of SPNDs and will be useful in the optimum design of new SPNDs for long term usage.

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Analysis of Improvement Method of Isolation Between Digital Noise and the Mobile Handset Antenna Title (디지털 노이즈와 휴대단말 안테나의 격리도 향상 방법 분석)

  • Kim, Joonchul
    • Journal of IKEEE
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    • v.23 no.2
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    • pp.474-478
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    • 2019
  • In this paper, we analyze the degradation of receiving sensitivity due to the coupling between digital noise and mobile handset antenna using characteristic mode. First, we analyze the coupling mechanism between the antenna and digital noise, and analyze the role of the decoupling capacitor of the ground signal line, which is one of the ways to improve the antenna receiving sensitivity degradation due to camera noise. For the analysis, the digital signal line and the ground line of the FPCB of the camera module are modeled as a loop type feeder that excites the characteristic mode of the PCB ground, and improved model which has a ground line with a capacitor are analyzed.

Comparison and Verification of Deep Learning Models for Automatic Recognition of Pills (알약 자동 인식을 위한 딥러닝 모델간 비교 및 검증)

  • Yi, GyeongYun;Kim, YoungJae;Kim, SeongTae;Kim, HyoEun;Kim, KwangGi
    • Journal of Korea Multimedia Society
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    • v.22 no.3
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    • pp.349-356
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    • 2019
  • When a prescription change occurs in the hospital depending on a patient's improvement status, pharmacists directly classify manually returned pills which are not taken by a patient. There are hundreds of kinds of pills to classify. Because it is manual, mistakes can occur and which can lead to medical accidents. In this study, we have compared YOLO, Faster R-CNN and RetinaNet to classify and detect pills. The data consisted of 10 classes and used 100 images per class. To evaluate the performance of each model, we used cross-validation. As a result, the YOLO Model had sensitivity of 91.05%, FPs/image of 0.0507. The Faster R-CNN's sensitivity was 99.6% and FPs/image was 0.0089. The RetinaNet showed sensitivity of 98.31% and FPs/image of 0.0119. Faster RCNN showed the best performance among these three models tested. Thus, the most appropriate model for classifying pills among the three models is the Faster R-CNN with the most accurate detection and classification results and a low FP/image.