• 센서학회지
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• 제22권6호
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• pp.410-414
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• 2013

As one of the effective methods for researching the objective tinnitus detection, the GPIAS (Gap Pre-pulse Inhibition of Acoustic Startle) measurement has been used to verify the existence of animal tinnitus objectively. The level and pattern of the background sound presented prior to a startle pulse are closely related with the GPIAS results. But the effect of the starting point of the background sound on animal startle responses has not been reported yet. In this paper, we present the implementation of a GPIAS measurement system based on an unconstrained enclosure to avoid animals' excessive constraint stress and deal with the animals' growth. After the performance of our implemented system has been tested through the animal experiment using 4 SD-rats, the effect of starting point of stimulus background sound on the startle response has been studied by the use of our implemented system. Through the results, it is verified that our system can measure the inhibition of animal startle responses due the gap pre-pulse for GPIAS calculation and the background sound starting point does not significantly effect on the startle response and the GPIAS values if the background sound continues for more than 300msec before a gap pre-pulse is presented.

• 한국소음진동공학회논문집
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• 제12권4호
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• pp.287-293
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• 2002

The unexpected failure of the induction motor makes the downtime of production, and the cost of the process cessation enormous. To reduce the downtime and increase the reliability of the motor, the vibration measurements for the fault detection have been used previously. Recently motor current signature analysis(MCSA) has been adapted for the fault detection and diagnosis of the motors. MCSA provides a powerful analysis tool for detecting the presence of mechanical and electrical faults in both the motor and driven equipment. In this paper, the fault severity of the rotor bar has been derived in terms of the resistance change which is calculated from the equivalent circuit model. Results show that the fault of the rotor can be easily detected and the measured value of the resistance change is verified by the detected fault from on-site tests using MCSA for the induction motors in an iron foundry.

• 한국자동차공학회논문집
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• 제8권1호
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• pp.23-31
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• 2000

Knock and misfire, kinds of abnormal combustion, are highly undesirable effect on the internal combustion engine. So, it is important to detect these avnormal combuition and control the ignition timing etc. to avoid these mal-effect factors in real engine system. In this study, the system which detects the knock and the misfire using by spark plug is presented. This system is based on the effect of modulation breakdown voltage(BDV) between the spark gaps. The voltage drop between spark plug electrodes, when an electrical breakdown is initiated, depends on the temperature and pressure in combustion chamber. So, we can detect knock and misfire that produce changes in gas temperature and pressure (consequently, its density) using by BDV signal change which carries information about the character of combustion.

• 한국압력기기공학회 논문집
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• 제16권2호
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• pp.25-34
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• 2020

As leakage in nuclear power plants could cause a variety of problems, it is very critical to monitor leakage from the safety point of view. Accordingly, a new type of leak detection system is currently being developed and flow characteristics of the sampling and transportation system are investigated by using numerical analysis as a part of the development process in this study. The results showed that the steam mass fraction varied according to the effect of the gap between the insulation and piping component, transportation velocity, and material properties of porous media during the sampling and transportation process. The results of this study should be useful for understanding flow characteristics of the sampling and transportation system and its design and application.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.268.2-268.2
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• 2013

Nanogap interdigitated electrodes (NIDEs) can serve as an alternative platform for the biomolecular detection [1]. In this work, the NIDEs were adopted in a simple and sensitive detection of Pneumococcal surface protein A (PspA). The NIDEs were fabricated by the combination of photo and chemical lithography. Photolithographically-defined initial gap of about 200 nm was narrowed down to a few tens of nanometers by surface-initiated growth of the initial electrodes (chemical lithography) [2]. Bare silicon oxide surface between the electrodes was chemically modified to immobilize capturing antibodies and, after exposure to the samples, the device was immersed in a solution containing the probe-antibody-conjugated Au nanoparticles (Au NPs). The conductance change accompanied with the Au NP immobilization was interpreted as the existence of PspA. Detection limit of the measurements and further improvement of the detection efficiency were discussed with the results from I-V analysis, scanning electron microscopy, and atomic force microscopy.

• 한국자기학회지
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• 제12권5호
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• pp.174-178
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• 2002

미소결함을 가진 금속체에 교류자기장을 인가하면 결함부근에는 와전류의 분포가 달라져 이에 의해 금속체를 관통하는 교류자기장은 결함부근에서 차이를 가진다. 이 교류자기장을 비정질 와이어로 된 센서헤드로 측정하여 센서헤드의 유기전압 크기로부터 결함 유무를 검출하는 방법에 대해 검토하였다. 비정질 와이어는 Co-based재료로 자왜가 거의 0이며 고투자율 자성체이고 비정질 와이어는 길이가 15mm, 직경이 100$\mu\textrm{m}$인 원주형 자성체이다. 실험대상 금속체로 0.5mm의 단일 직선 갭을 가진 두께 1mm의 동판과 0.1mm의 갭이 규칙적으로 배열된 두께 25$\mu\textrm{m}$의 Al 판를 이용하였다. 스파이럴 코일에 인가하는 교류자기장의 주파수는 100KHz~600KHz였다. 본 실험의 결과에서 동판에서는 유기전압의 최대치와 최소치의 차가 약 2.5㎷ 얻어졌고, Al판에서는 500KHz에서 0.4㎷가 얻어져 직선 갭의 유무를 유기전압의 크기만으로 확인할 수 있었다.

• 한국정보통신학회논문지
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• 제24권2호
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• pp.204-211
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• 2020

본 논문에서는 약한 지도학습을 통한 주 객체 위치 검출을 위한 최적의 딥러닝 네트워크 구조를 제안한다. 제안된 네트워크는 약한 지도학습을 통한 주 객체의 위치 검출 정확도를 향상시키기 위해 컨벌루션 블록을 추가하였다. 추가적인 딥러닝 네트워크는 VGG-16을 기반으로 합성곱 층을 더해주는 5가지 추가적인 블록으로 구성되며 객체의 실제 위치 정보가 필요하지 않는 약한 지도 학습의 방법으로 학습하였다. 또한 객체의 위치 검출에는 약한 지도학습의 방법 중, CAM에서 GAP이 필요하다는 단점을 보완한 Grad-CAM을 사용하였다. 제안한 네트워크는 CUB-200-2011 데이터 셋을 이용하여 성능을 테스트하였으며 Top-1 Localization Error를 산출하였을 때 50.13%의 결과를 얻을 수 있었다. 또한 제안한 네트워크는 기존의 방법보다 주 객체를 검출하는데 더 높은 정확도를 보인다.

• 한국환경성돌연변이발암원학회지
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• 제23권2호
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• pp.56-62
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• 2003

The liver progenitor cells could form a potential target cell population fore both tumor-initiating and -promoting chemicals. Induction of drug-metabolizing and antioxidant enzymes, including AhR-dependent CYP1A1, NQO-1 and AKR1C9, was detected in the rat liver epithelial WB-F344 "stem-like" cells. Additionally, WB-F344 cells express a functional, wild-type form of p53 protein, a biomarker of genotoxic events, and connexin 43, a basic structural unit of gap junctions forming an important type of intercellular communication. In this cellular model, two complementary assays have been established for detection of the modes of action associated with tumor promotion: inhibition of gap junctional intercellular communication (GJIC) and proliferative activity in confluent cells. We found that the PAHs and PCBs, which are AhR agonists, released WB-F344 cells from contact inhibition, increasing both DNA synthesis and cell numbers. Genotoxic effects of some PAHs that lead to apoptosis and cell cycle delay might interfere with the proliferative activity of PAHs. Contrary to that, the nongenotoxic low-molecular-weight PAHs and non-dioxin-like PCB congeners, abundant in the environment, did not significantly affect cell cycle and cell proliferation; however both groups of compounds inhibited GJIC in WB-F344 cells. The release from contact inhibiton by a mechanism that possibly involves the AhR activation, inhibition of GJIC and genotoxic events induced by environmental contaminants are three important modes of action that could play an important role in carcinogenic effects of toxic compounds. The relative potencies to inhibit GJIC, to induce AhR-mediated activity, and to release cells from contact inhibition were determined for a large series of PAHs and PCBs and their metabolites. In vitro bioassays based on detection of events on cellular level (deregulation of GJIC and/or proliferation) or determination of receptor-mediated activities in both ?$stem-like^{\circ}{\times}$ and hepatocyte-like liver cellular models are valuable tools for detection of modes of action of polyaromatic hydrocarbons. They may serve, together with concentration data, as a first step in their risk assessment.

• Molecules and Cells
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• 제39권11호
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• pp.807-813
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• 2016

Escherichia coli are important indicator organisms, used routinely for the monitoring of water and food safety. For quick, sensitive and real-time detection of E. coli we developed a 2'F modified RNA aptamer Ec3, by Cell-SELEX. The 31 nucleotide truncated Ec3 demonstrated improved binding and low nano-molar affinity to E. coli. The aptamer developed by us out-performs the commercial antibody and aptamer used for E. coli detection. Ec3(31) aptamer based E. coli detection was done using three different detection formats and the assay sensitivities were determined. Conventional Ec3(31)-biotin-streptavidin magnetic separation could detect E. coli with a limit of detection of $1.3{\times}10^6CFU/ml$. Although, optical analytic technique, biolayer interferometry, did not improve the sensitivity of detection for whole cells, a very significant improvement in the detection was seen with the E. coli cell lysate ($5{\times}10^4CFU/ml$). Finally we developed Electrochemical Impedance Spectroscopy (EIS) gap capacitance biosensor that has detection limits of $2{\times}10^4CFU/mL$ of E. coli cells, without any labeling and signal amplification techniques. We believe that our developed method can step towards more complex and real sample application.

• 대한기계학회논문집B
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• 제35권10호
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• pp.1075-1081
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• 2011

이중벽관 증기발생기에서 전열관의 내관과 외관 사이의 틈새에 채워진 헬륨가스의 압력변동으로 전열관의 파손을 감지하는 방법이 개발되고 있다. 이 현상을 모사하기 위해 압력으로 밀착된 두 평판사이의 미세한 틈새에서의 누설률을 측정하여 실험식을 개발하였다. 이 실험식에서는 틈새의 간격과 유동마찰계수가 표면조도에 의해 상호 결합된 형태로 기술되는데, 간단한 평판접촉 모델을 사용하여 유동마찰계수 식을 분리하였다. 이 실험식과 균열에서의 누설률 예측에 사용되고 있는 기존의 유동마찰계수 관련 실험식들을 상호 비교하였다. 레이놀즈 수의 적용범위가 상이함에도 불구하고 개발한 실험식이 0.1~0.35 에서는 레이놀즈 수가 높은 경우에 적용되는 실험식들과 유사한 값을 보였다.