• Journal of Sensor Science and Technology
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• v.10 no.4
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• pp.239-249
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• 2001

LAPS is a device which is dependent on the bias potential between a pH sensitivity and alternating photocurrent. We implemented the multichannel LAPS device and the detection system which was able to effectively measure the sensor's output by a synchronized detection circuit and multiple methods. The implemented LAPS was structured the multiple sensing sites for analyzing a various components simultaneously. And the system included a time-division method using one pre-amplifier being able to detect the multichannel pH concentration preserving a high S/N ratio and a control part. System hardware consists of a pre-amplifier, digital unit and sensor unit, and software consists of a system program and PC program. As results, we verified the successful operations of system including an implemented pre-amplifier and signal processing units.

• Journal of Sensor Science and Technology
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• v.25 no.1
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• pp.51-56
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• 2016

This study evaluates the performance of an optical sensor and measurement system (CMA-24) which can analyze the fluctuation of dissolved oxygen and pH simultaneously. In the optical sensor system, the fluorescent materials, Rudpp and HPTS which are sensitive to dissolved oxygen and pH, respectively, are coated on the bottom of a 24-well -plate by the sol-gel technology. The detection times of the emission light of the oxygen sensor were $4,186{\pm}13.90{\mu}s$ and $4,452{\pm}36.68{\mu}s$ for the dissolved oxygen of 17% $O_2$ and 7.6% $O_2$, respectively. On the other hand, the detection times of the pH sensor were $6,699.43{\pm}14.64{\mu}s$, $6,722.24{\pm}6.21{\mu}s$, and $6,748.52{\pm}2.63{\mu}s$ using pH 6, 7, and 8, respectively. When we determined cellular respiration levels of C2C12 myocytes with CMA-24, $O_2$/pH measurement system, the ratio of the uncoupled to coupled OCR (oxygen consumption rate) was 1.41. The results mean that this CMA-24 system shows almost the same sensitiveness as the commercial system.

• Journal of the Korea Society for Simulation
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• v.28 no.2
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• pp.89-95
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• 2019

This paper introduces the simulation concepts and technical approach of underwater weapon system performance analysis simulator, especially focused on probabilistic target detection concepts. We calculated the signal excess (SE) value using SONAR equation, then derived the probability density function(PDF) for target presence($H_1$) or absence($H_0$) cases, respectively. With the Neyman-Pearson detector criterion, we got the probability of detection($P_D$) while satisfying the given probability of false alarm($P_{FA}$). At every instance of simulation, target detection is decided in the probabilistic perspective. With the proposed detection implementation, we improved the model fidelity so that it could support the tactical decision during the operation.

• International Journal of Automotive Technology
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• v.8 no.4
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• pp.493-504
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• 2007

This paper proposes a stereo vision-based forward obstacle detection and distance measurement method. In general, stereo vision-based obstacle detection methods in automotive applications can be classified into two categories: IPM (Inverse Perspective Mapping)-based and disparity histogram-based. The existing disparity histogram-based method was developed for stop-and-go applications. The proposed method extends the scope of the disparity histogram-based method to highway applications by 1) replacing the fixed rectangular ROI (Region Of Interest) with the traveling lane-based ROI, and 2) replacing the peak detection with a constant threshold with peak detection using the threshold-line and peakness evaluation. In order to increase the true positive rate while decreasing the false positive rate, multiple candidate peaks were generated and then verified by the edge feature correlation method. By testing the proposed method with images captured on the highway, it was shown that the proposed method was able to overcome problems in previous implementations while being applied successfully to highway collision warning/avoidance conditions, In addition, comparisons with laser radar showed that vision sensors with a wider FOV (Field Of View) provided faster responses to cutting-in vehicles. Finally, we integrated the proposed method into a longitudinal collision avoidance system. Experimental results showed that activated braking by risk assessment using the state of the ego-vehicle and measuring the distance to upcoming obstacles could successfully prevent collisions.

• YAKHAK HOEJI
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• v.37 no.4
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• pp.362-364
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• 1993

The sensitive detection of free fatty acids was investigated by using H$_{2}$O$_{2}$-bis(2,4,6-trichlorophenyl) oxalate chemiluminescence system after monodansyl cadaverine labeling. Because dansvl moiety is well excited by this chemiluminescence system, monodansyl cadaverine was a prominent reagent to this system for the determination of free fatty acids. The cluent of 50mM tris-HCI buffer (pH 7.7)-acetonitrile (1:4, v/v) was run through TSK gel ODS 80 TM column. The reagent solutions were mixed with the eluent containing the monodansyl cadaverine derivative of fatty acids from the column. By this system, linolic acid was detected 50 fmol by injected amount.

• Food Engineering Progress
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• v.21 no.2
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• pp.180-186
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• 2017

Salt, as food, is the most essential element for human survival due to its significant physiological functions. Here, we report the simultaneous detection of Pb and Cd in sea salt by square wave anodic stripping voltammetry (SWASV). Stripping voltammetric measurements were conducted using a manufactured rotating disk electrode system (MRDES). The detection limit was $3.6{\pm}0.18{\mu}gL^{-1}$ for Pb and $3.9{\pm}0.37{\mu}gL^{-1}$ Cd in NaCl solution. When the pH increased from 5.5 to 8.5, the peak currents of Pb and Cd decreased. At a pH of 8.3, the ratio of the current drop compared with that at a pH of 5.5 was 0.6 for Pb and 0.73 for Cd. The concentrations corrected by the current drop are in agreement with the concentrations obtained with ICP (inductively coupled plasma). This system demonstrates the reliable detection of heavy metals in aqueous media and, at a high $Na^+$ concentration, the successful application for the determination of Pb and Cd in sea salts.

• Journal of the Korean Chemical Society
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• v.33 no.4
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• pp.388-398
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• 1989

A continuous-automated method for the determination of nitrite ion using gas-sensing membrane electrode was developed. The pH electrode of tubular PVC membrane type was used as a detector of this system. The slope of linear response of the electrode measured at optimum conditions for the continuous-automated determination of nitrite ion was 63.5 mV/decade. The concentration range of linear response and detection limit were 2.5 ${\times}10^{-4}{\sim}\;7.5{\times}10^{-2}$M and $8.0{\times}10^{-5}$M, respectively. This detection system was not only less interfering to acidic gas species than other methods but also less time consumable for determination.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1563-1570
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• 2010

To construct a highly sensitive detection system for endocrine disruptors (EDs), we have compared the activity of promoters with the n-alkane-inducible cytochrome P450 gene (ALK1), isocitrate lyase gene (ICL1), ribosomal protein S7 gene (RPS7), and the translation elongation factor-1${\alpha}$ gene (TEF1) for the heterologous gene in Yarrowia lipolytica. The promoters were introduced into the upstream of the lacZ or hERa reporter genes, respectively, and the activity was evaluated by ${\beta}$-galactosidase assay for lacZ and Western blot analysis for hER${\alpha}$. The expression analysis revealed that the ALK1 and ICL1 promoters were induced by n-decane and by EtOH, respectively. The constitutive promoter of RPS7 and TEF1 showed mostly a high level of expression in the presence of glucose and glycerol, respectively. In particular, the TEF1 promoter showed the highest ${\beta}$-galactosidase activity and a significant signal by Western blotting with the anti-estrogen receptor, compared with the other promoters. Moreover, the detection system was constructed with promoters linked to the upstream of the expression vector for the hER${\alpha}$ gene transformed into the Y. lipolytica with a chromosome-integrated lacZ reporter gene under the control of estrogen response elements (EREs). It was indicated that a combination of pTEF1p-hER${\alpha}$ and CXAU1-2XERE was the most effective system for the $E_2$-dependent induction of the ${\beta}$-galactosidase activity. This system showed the highest ${\beta}$-galactosidase activity at $10^{-6}\;M\;E_2$, and the activity could be detected at even the concentration of $10^{-10}\;M\;E_2$. As a result, we have constructed a strongly sensitive detection system with Y. lipolitica to evaluate recognized/suspected ED chemicals, such as natural/synthetic hormones, pesticides, and commercial chemicals. The results demonstrate the utility, sensitivity, and reproducibility of the system for identifying and characterizing environmental estrogens.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.395-398
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• 1997

Human pulse represents the physical characteristics of heart and cardiovascular system. Therefore, malfunctions and errors of heart and cardiovascular system can be determined by using an automatic diagnosis system that can detect the pulse signal. Not only will the computerised system preclude the possibilities of observational errors by giving an accurate measurement with great stability, but minimize the possibilities of misinterpretation by using an automated diagnostic logic. A new combinational fiber-optic sensor, which has a detecting part and a transmitting part was used to acquire radial pulse signal noninvasively. The development of P-5 transducer makes it possible to obtain more effective detection and obvious display of pulse signals in the aspect of reliability. Using P-5 transducer in the field of plethysomography and MAC- JIN, one of our diagnoses in Korean traditional medicine, it is expected that we can ontain quantitative and valuable information or the diagnosis of human pulses.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.175-177
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• 1995

The sensor signal validation and failure detection system must be able to detect, isolate, and identify sensor degradation as well as provide a reconstruction of the measurements. In this study, this is accomplished by combining the neural network, the Generalized Consistency Checking(GCC), and the Sequential Probability Ratio Test(SPRT) method in a decision estimator module. The GCC method is a computationally efficient system for redundant sensors, while the SPRT provides the ability to make decisions based on the degradation history of a sensor. The methodology is also extended to the detection of noise degradation. The acceptability of the proposed method is demonstration by using the simulation data in safety injection accident of nuclear power plants. The results show that the signal validation and sensor failure detection system is able to detect and isolate a bias failure and noise type failures under transient conditions. And also, the system is able to provide the validated signal by reconstructing the measurement signals in the failure conditions considered.