• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.1
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• pp.70-79
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• 2016

This paper proposes a low-power range-scaled 14b 30 MS/s pipeline-SAR composite ADC for high-performance CIS applications. The SAR ADC is employed in the first stage to alleviate a sampling-time mismatch as observed in the conventional SHA-free architecture. A range-scaling technique processes a wide input range of 3.0VP-P without thick-gate-oxide transistors under a 1.8 V supply voltage. The first- and second-stage MDACs share a single amplifier to reduce power consumption and chip area. Moreover, two separate reference voltage drivers for the first-stage SAR ADC and the remaining pipeline stages reduce a reference voltage disturbance caused by the high-speed switching noise from the SAR ADC. The measured DNL and INL of the prototype ADC in a $0.18{\mu}m$ CMOS are within 0.88 LSB and 3.28 LSB, respectively. The ADC shows a maximum SNDR of 65.4 dB and SFDR of 78.9 dB at 30 MS/s, respectively. The ADC with an active die area of $1.43mm^2$ consumes 20.5 mW at a 1.8 V supply voltage and 30 MS/s, which corresponds to a figure-of-merit (FOM) of 0.45 pJ/conversion-step.

• Korean Journal of Veterinary Service
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• v.27 no.1
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• pp.7-15
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• 2004

For measuring general bacterial count and Escherichia coli count, the standard plate count was used to conduct a test on 113 cases of pork carcass surfaces from slaughterhouses in Incheon area from January to February 2003. And Salmonella spp, Staphylococcus aureus and Listeria monocytogenes was used to conduct a test on 68 cases of pork carcass surfaces and 76 cases of feces, that is to say, a total of 144 cases. The results were obtained as follows: In the case of general bacterial count, 29 cases(25.7%) were in the range of 100∼999 and 62 cases(54.9%) were in the range of 1,000∼9,999 and 22 cases(19.4%) were in the range of 10,000∼99,999. Meanwhile as regards E coli count, 22 cases(19.4%) were in the range of 1∼9 and 69 cases(61.2%) were in the range of 10∼99 and 22 cases(19.4%) were in the range of 100∼999. On 68 cases of pork carcass surfaces, 7 strains(10.2%) of Salmonella spp, and 12 strains(17.6%) of S aureus were detected and 27 strains(39.7%) of L monocytogenes, respectively. As for the detected Salmonella spp, 6 strains of the B group, 3 strains of S enterica subsp salame and 2 strains of S typhimurium were detected, respectively. On 76 cases of feces, 14 strains(18.4%) of Salmonella spp, and 15 strains(19.7%) of L monocytogenes and 14 strains(18.4%) of S aureus were detected respectively. As for the detected Salmonella spp, 6 strains of the B group, 4 strains of S derby and 8 strains of the C group, 5 strains of S rissen were detected, respectively. All of 42 strains of L monocytogenes were type 1. As a result of conducting a toxin test on the detected S aureus, all of 26 strains were found to be non-toxin.

• Journal of the Korean Applied Science and Technology
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• v.28 no.1
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• pp.64-74
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• 2011

The aim of study was to investigate polluted amounts 16 PAHs in railroad(waste railway ties) area, factory area and land-fill area. All of the samples were analyzed by GC-MSD(SIM mode), and the recovery range, detection limit and standard deviation obtained by this experiment were 73.88 ~ 94.75%, 0.009 ~ 2.252 ${\mu}g$/kg and 1.861 ~ 12.373, respectively. The concentrations of total PAHs(t-PAHs) and total carcinogenic PAHs(t-PAHcarc) in soils of three area were in the range of 12.54 ~ 3274.95 ${\mu}g$/kg on a wet weight basis with a mean value of 499.8 ${\mu}g$/kg and 0 ~122.77 ${\mu}g$/kg with a mean value of 20.16 ${\mu}g$/kg, respectively. The correlation between t-PAHs and t-PAHcarc appeared very high in railroad(waste railway ties) area ($R^2$ = 0.8301), factory area ($R^2$ = 0.9217) except land-fill area($R^2$ = 0.3782), indicated that t-PAHcarc concentration increases in proportion with t-PAHs.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.157-157
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• 2019

This study derived the Flood-Inducing-Rainfall (FIR) and the Flood-Inducing-Runoff (FIRO) from the radar-gage composite data to be used as the basis of the flood warning initiation for the urban area of Seoul. For this, we derived the rainfall depth-duration relationship for the 261 flood events at 239 watersheds during the years 2010 and 2011 based on the 10-minute 1km-1km radar-gauge composite rainfall field. The relationship was further refined by the discrete ranges of the proportion of the flooded area in the watershed (FP) and the coefficient variation of the rainfall time series (CV). Then, the slope of the straight line that contains all data points in the depth-duration relationship plot was determined as the FIR for the specified range of the FP and the CV. Similar methodology was applied to derive the FIRO, which used the runoff depths that were estimated using the NRCS Curve Number method. We found that FIR and FIRO vary at the range of 37mm/hr-63mm/hr and the range of 10mm/hr-42mm/hr, respectively. The large variability was well explained by the FP and the CV: As the FP increases, FIR and FIRO increased too, suggesting that the greater rainfall causes larger flooded area; as the rainfall CV increases, FIR and FIRO decreased, which suggests that the temporally concentrated rainfall requires less total of rainfall to cause the flood in the area. We verified our result against the 21 flood events that occurred for the period of 2012 through 2015 for the same study area. When the 5 percent of the flooded area was tolerated, the ratio of hit-and-miss of the warning system based on the rainfall was 44.2 percent and 9.5 percent, respectively. The ratio of hit-and-miss of the warning system based on the runoff was 67 percent and 4.7 percent, respectively. Lastly, we showed the importance of considering the radar-gauge composite rainfall data as well as rainfall and runoff temporal variability in flood warning system by comparing our results to the ones based on the gauge-only or radar-only rainfall data and to the one that does not account for the temporal variability.

• Journal of Korea Multimedia Society
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• v.15 no.10
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• pp.1228-1235
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• 2012

In this Paper, we propose an energy efficient localization technique based on WUSB (Wireless USB) over WBAN (Wireless Body Area Networks) protocol required for Wearable Computer systems. For this purpose, the proposed localization algorithm minimizes power consumption and estimates location without range information. It is executed independently on the basis of WUSB over WBAN protocol at each sensor node comprising peripherals of a wearable computer system. And it minimizes power consumption by estimating locations of sensor nodes with range-free method fast.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.108-111
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• 2016

We propose the method for measuring sensitivity of optical receiver of a long-range laser range finder in real-time. The sensitivity of the detector can be calculated using the detected voltage of the reference sensor, the area of the reference sensor and the transmittance ratio of neutral density filters. To evaluate the performance of the proposed method, we implemented a system and performed experiments. As a result, this system can be measured from 2nW to $113{\mu}W$. With this system, we measured the sensitivity of 37nW and 7nW with PIN PD and APD sample, respectively. This system has the advantage for the performance test of an optical sensor module in the long-range laser range finder.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.938-941
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• 2003

As the application area of range finder initially developed for military purpose has been extended, the necessity of precision measurement for long distance and its miniaturization is being presented. Recently, LRF(Laser Range Finder) is widely used because it shows more accurate results of range finding. However, most of LRFs use laser source which have wavelength ranges harmful to the human eyes. In this study, we developed the LRF using OPO(Optical Parametric Oscillator) which can stretch laser wavelength to safe region and realized more compact one using solid state laser

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.4
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• pp.383-390
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• 2001

Long-range guided wave inspection is a new emerging technology for rapidly and globally inspecting a large area of a structure from a single test location. This paper describes a general overview of the guided wave properties and its application for long-range inspection of structures the principle and instrument system for a guided wave inspection technology called "magnetostrictive sensor (MsS)" that generates and detects guided waves electromagnetically in the material under testing, and examples of long-range guided wave inspection of structures that can be accomplished using the MsS.

• Journal of the Optical Society of Korea
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• v.20 no.5
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• pp.628-632
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• 2016

We studied experimentally and theoretically the vertical range of the confined electric field in the gap area of metamaterials, which was analyzed for various gap widths using terahertz time-domain spectroscopy. We measured the resonant frequency as a function of the thickness of poly(methyl methacrylate) in the range 0 to 3.2 μm to quantify the effective detection volumes. We found that the effective vertical range of the metamaterial is determined by the size of the gap width. The vertical range was found to decrease as the gap width of the metamaterial decreases, whereas the sensitivity is enhanced as the gap width decreases due to the highly concentrated electric field. Our experimental findings are in good agreement with the finite-difference time-domain simulation results. Finally, a numerical expression was obtained for the vertical range as a function of the gap width. This expression is expected to be very useful for optimizing the sensing efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.5
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• pp.808-811
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• 2022

In this paper, a wide-range microphone system for lectures using dual 3D sensors is proposed. A previous work using a single sensor had lowering the detecting threshold to support wide-area. However it was found that an error occurred when lecturer wears clothes with low reflectivity or has small body size. When multiple sensors are used to expand the coverage it could be cause various problems. Each sensor could show different distance to the same target. We derive the rotation angle and and compensate for lecturing microphone system using sensors on the line. The proposed method shows a little improvement in performance by about 1dB compared to the previous works but the performance is uniform in all areas regardless of reflectivity.