• Biomedical Science Letters
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• v.14 no.2
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• pp.115-118
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• 2008

Salmonella typhi is frequent causes of foodborne illness and its detection is important for monitoring disease progression. In this study, by using general PCR and novel LAMP (Loop Mediated Isothermal Amplification) assay, we evaluated the usefulness of LAMP assay for detection of Salmonella typhi. In this LAMP assay, forward inner primer (FIP) and back inner primer (BIP) was specially designed for recognizing target invA gene. Target DNA was amplified and visualized as ladder-like pattern of bands on agarose gel within 60 min under isothermal conditions at $65^{\circ}C$. When the sensitivity and reproducibility of LAMP were compared to general PCR, there was no difference of reproducibility but sensitivity of LAMP assay was more efficient than PCR (the detection limit of LAMP assay was 30 fg, while the PCR assay was 3 pg). These results indicate that the LAMP assay is a potential and valuable means for detection of Salmonella typhi, especially for its rapidity, simplicity and low cost.

• The Korean Journal of Food And Nutrition
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• v.13 no.1
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• pp.1-5
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• 2000

Detection for heat-labile enterotoxin(LT) of enterotoxigenic Escherichia coli(ETEC, EC81, O148:H28) and enterotoxin of enterotoxigentic Clostridium perfringents type A(CP, NCTC8238, Hobbs serotype 2) by use of a polymerase chain reaction (PCR) assay were positive reaction, which using LT gene-specific primers of ETEC with a detection limit equivalent from 100ng/${\mu}\ell$ to 1 pg of a DNA fragment of 417-bp in EC81 and enterotoxin gene-specific primers of CP with a detection limit equivalent from 100ng/${\mu}\ell$ to 10pg of a DNA fragment of 364-bp in NCTC8238. Detection for a LT gene of ETEC highly appeared 10-fold sensitivity than an enterotoxin gene of CP.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.7
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• pp.521-526
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• 2018

In particular, gas sensors require characteristics such as high speed, sensitivity, and selectivity. In this study, we fabricated a $NO_X$ gas sensor by using a multi-walled carbon nanotube (MWCNT)/zinc oxide (ZnO) composite film. The fabricated MWCNT/ZnO gas sensor was then treated by a $450^{\circ}C$ temperature process to increase its detection sensitivity for NOx gas. We compared the detection characteristics of a ZnO film gas sensor, MWCNT film gas sensor, and the MWCNT/ZnO composited film gas sensor with and without the heat-treatment process. The fabricated gas sensors were used to detect $NO_X$ gas at different concentrations. The gas sensor absorbed $NO_X$ gas molecules, exhibiting increased sensitivity. The sensitivity of the gas sensor was increased by increasing the gas concentration. Additionally, while changing the temperature inside the chamber for the MWCNT/ZnO composite film gas sensor, we obtained its sensitivity for detecting $NO_X$ gas. Compared with ZnO, the MWCNT film gas sensor is excellent for detecting $NO_X$ gas. From the experimental results, we confirmed the enhanced gas sensor sensing mechanism. The increased effect by electronic interaction between the MWCNT and ZnO films contributes to the improved sensor performance.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.4
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• pp.29-39
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• 2002

In general, the intrusion detection method of anomalous behaviors has high false alarm rate which contains false-positive and false-negative. To increase the sensitivity of intrusion detection, we propose a method of aggregate detection to reduce false alarm rate by using correlation between misuse activity detection sensors and anomalous ones. For each normal behavior and anomalous one, we produce the reflection rate between the result from one sensor and another in off-line. Then, we apply this rate to the result of real-time detection to reduce false alarm rate.

• Structural Monitoring and Maintenance
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• v.7 no.3
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• pp.261-281
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• 2020

Civil structures may experience progressive deterioration and damage under environmental and operational conditions over their service life. Finite element (FE) model updating method is one of the most important approaches for damage identification in structures due to its capabilities in structural health monitoring. Although various damage detection approaches have been investigated on structures, there are limited studies on large-sized space structures. Thus, this paper aims to investigate the applicability and efficiency of sensitivity-based FE model updating framework for damage identification in large space structures from a distinct point of view. This framework facilitates modeling and model updating in large and geometric complicated space structures. Considering sensitivity-based FE model updating and vibration measurements, the discrepancy between acceleration response data in real damaged structure and hypothetical damaged structure have been minimized through adjusting the updating parameters. The feasibility and efficiency of the above-mentioned approach for damage identification has finally been demonstrated with two numerical examples: a flat double layer grid and a double layer diamatic dome. According to the results, this method can detect, localize, and quantify damages in large-scaled space structures very accurately which is robust to noisy data. Also, requiring a remarkably small number of iterations to converge, typically less than four, demonstrates the computational efficiency of this method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.529-536
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• 2001

We investigate a surface-micromachined capacitive accelerometer with the grid-type electrodes surrounded by a perforated proof-mass frame. An electromechanical analysis of the microaccelerometer has been performed to obtain analytical formulae for natural frequency and output sensitivity response estimation. A set of prototype devices has been designed and fabricated based on a 4-mask surface-micromachining process. The resonant frequency of 5.8$\pm$0.17kHz and the detection sensitivity of 0.28$\pm$0.03mV/g have been measured from the fabricated devices. The parasitic capacitance of the detection circuit with a charge amplifier has been measured as 3.34$\pm$1.16pF. From the uncertainty analysis, we find that the major uncertainty in the natural frequency of the accelerometer comes from the micromachining error in the beam width patterning process. The major source of the sensitivity uncertainty includes uncertainty of the parasitic capacitance, the inter-electrode gap and the resonant frequency, contributing to the overall sensitivity uncertainty in the portions of 75%, 14% and 11%, respectively.

• Journal of Sensor Science and Technology
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• v.22 no.5
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• pp.357-363
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• 2013

An ultraviolet pulsed laser ablation of polyimide film coated with platinum has been used to enhance the sensitivity for the application as an electrochemical biosensor. Densely packed cones are formed on polyimide surface after UV irradiation which results in increase of surface area. In order to apply the sensitivity improvement of laser ablated polyimide film electrodes, the glucose oxidase modified biosensor was fabricated by using an encapsulation in the gel matrix through sol-gel transition of tetraethoxysliane on the surface of laser ablated polyimide film. The optimum conditions for glucose determination have been characterized with respect to the applied potential and pH. The linear range and detection limit of glucose detection were from 2.0 mM to 18.0 mM and 0.18 mM, respectively. The sensitivity of glucose biosensors fabricated with laser ablated polyimide film is about three times higher than that of plain polyimide film due to increase in surface area by laser ablation.

• Imaging Science in Dentistry
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• v.44 no.2
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• pp.115-119
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• 2014

Purpose: The aim of this in vitro study was to determine the sensitivity and specificity of cone-beam computed tomography (CBCT) and digital periapical radiography in the detection of mesial root perforations of mandibular molars. Materials and Methods: In this in vitro study, 48 mandibular molars were divided into 4 groups. First, the mesial canals of all the 48 teeth were endodontically prepared. In 2 groups (24 teeth each), the roots were axially perforated in the mesiolingual canal 1-3 mm below the furcation region, penetrating the root surface ("root perforation"). Then, in one of these 2 groups, the mesial canals were filled with gutta-percha and AH26 sealer. Mesial canals in one of the other 2 groups without perforation (control groups) were filled with the same materials. The CBCT and periapical radiographs with 3 different angulations were evaluated by 2 oral and maxillofacial radiologists. The specificity and sensitivity of the two methods were calculated, and P<0.05 was considered significant. Results: The sensitivity and specificity of CBCT scans in the detection of obturated root canal perforations were 79% and 96%, respectively, and in the case of three-angled periapical radiographs, they were 92% and 100%, respectively. In non-obturated root canals, the sensitivity and specificity of CBCT scans in perforation detection were 92% and 100%, respectively, and for three-angled periapical radiographs, they were 50% and 96%, respectively. Conclusion: For perforation detection in filled-root canals, periapical radiography with three different horizontal angulations would be trustworthy, but it is recommended that CBCT be used for perforation detection before obturating root canals.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7981-7984
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• 2014

Purpose: Colorectal cancer (CRC) screening with fecal occult blood testing (FOBT) has been associated with a reduction in CRC incidence and CRC-related mortality. However, a conventional FOBT requires stool collection and handling, which may be inconvenient for participants. The EZ-Detect$^{TM}$ (Siam Pharmaceutical Thailand) is a FDA-approved chromogen-substrate based FOBT which is basically a self-checked FOBT (no stool handling required). This study aimed to evaluate the accuracy of EZ-Detect for CRC detection. Methods: This prospective study was conducted in the Faculty of Medicine, Siriraj Hospital, Bangkok, Thailand between November 2013 and May 2014. Some 96 patients with histologically-proven CRC and 101 patients with normal colonoscopic findings were invited to perform self-checked FOBT according to the manufacturer's instructions. Results were compared with endoscopic and pathologic findings. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for CRC detection were calculated. Results: The present study revealed the sensitivity, specificity, PPV and NPV of this self-checked FOBT for CRC detection to be 41% (95% CI: 31-51), 97% (95% CI: 92-99), 93% (95% CI: 81-98) and 63% (95% CI: 55-70), respectively. The overall accuracy of the self-checked FOBT for identifying CRC was 70%. The sensitivity for CRC detection based on 7th AJCC staging was 29% for stage I, 32% for stage II and 50% for stage III/IV (P=0.19). The sensitivity was 33% for proximal colon and 42% for distal colon and rectal cancer (P=0.76). Notably, none of nine infiltrative lesions gave a positive FOBT. Conclusions: The self-checked FOBT had an acceptable accuracy of CRC detection except for infiltrative tumors. This home-administrated or 'DIY' do-it-yourself FOBT could be considered as one non-invasive and convenient tool for CRC screening.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.705-707
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• 2017

Stereo-based spatial radiation detection devices can obtain not only spatial distribution information about the radiation source but also distance information from the detection device to the source. And it provides more efficient information on the source than the existing radiation imaging device. In order to provide high-speed information on the spectrum and type of gamma-ray source, a high-sensitivity detection sensor with high sensitivity is required, and a technique capable of solving the saturation phenomenon at a high dose is needed. In this paper, we constructed a high sensitivity sensor for the measurement of multiple gamma - ray spatial distributions using improved function of detection module to solve saturation to high dose and conducted research to increase the scope of a single detector. The result of this paper improves the performance of gamma ray.