• Progress in Medical Physics
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• v.28 no.3
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• pp.111-121
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• 2017

Verification of dose distribution is an essential part of ensuring the treatment planning system's (TPS) calculated dose will achieve the desired outcome in radiation therapy. Each measurement have uncertainty associated with it. It is desirable to reduce the measurement uncertainty. A best approach is to reduce the uncertainty associated with each step of the process to keep the total uncertainty under acceptable limits. Point dose patient specific quality assurance (QA) is recommended by American Association of Medical Physicists (AAPM) and European Society for Radiotherapy and Oncology (ESTRO) for all the complex radiation therapy treatment techniques. Relative and absolute point dose measurement methods are used to verify the TPS computed dose. Relative and absolute point dose measurement techniques have a number of steps to measure the point dose which includes chamber cross calibration, electrometer reading, chamber calibration coefficient, beam quality correction factor, reference conditions, influences quantities, machine stability, nominal calibration factor (for relative method) and absolute dose calibration of machine. Keeping these parameters in mind, the estimated relative percentage uncertainty associated with the absolute point dose measurement is 2.1% (k=1). On the other hand, the relative percentage uncertainty associated with the relative point dose verification method is estimated to 1.0% (k=1). To compare both point dose measurement methods, 13 head and neck (H&N) IMRT patients were selected. A point dose for each patient was measured with both methods. The average percentage difference between TPS computed dose and measured absolute relative point dose was 1.4% and 1% respectively. The results of this comparative study show that while choosing the relative or absolute point dose measurement technique, both techniques can produce similar results for H&N IMRT treatment plans. There is no statistically significant difference between both point dose verification methods based upon the t-test for comparing two means.

• Journal of the Korean Society of Tobacco Science
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• v.35 no.1
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• pp.1-6
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• 2013

Near InfraRed Spectroscopy(NIRS) is a quick and accurate analytical method to measure multiple components in tobacco manufacturing process. This study was carried out to develop calibration equation of near infrared spectroscopy for the prediction of the amount of chemical components and hot water solubles(HWS) of reconstituted tobacco leaf. Calibration samples of reconstituted tobacco leaf were collected from every lot produced during one year. The calibration equation was formulated as modified partial least square regression method (MPLS) by analyzing laboratory actual values and mathematically pre-treated spectra. The accuracy of the acquired equation was confirmed with the standard error of prediction(SEP) of chemical components in reconstituted tobacco leaf samples, indicated as coefficient of determination($R^2$) and prediction error of sample unacquainted, followed by the verification of model equation of laboratory actual values and these predicted results. As a result of monitoring, the standard error of prediction(SEP) were 0.25 % for total sugar, 0.03 % for nicotine, 0.03 % for chlorine, 0.16 % for nitrate, and 0.38 % for hot water solubles. The coefficient of determination($R^2$) were 0.98 for total sugar, 0.97 for nicotine, 0.96 for chlorine, 0.98 for nitrate and 0.92 for hot water solubles. Therefore, the NIRS calibration equation can be applicable and reliable for determination of chemical components of reconstituted tobacco leaf, and NIRS analytical method could be used as a rapid and accurate quality control method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3856-3863
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• 2012

A 3D reconstruction technique from stereo images that requires minimal intervention from the user has been developed. The reconstruction problem consists of three steps of estimating specific geometry groups. The first step is estimating the epipolar geometry that exists between the stereo image pairs which includes feature matching in both images. The second is estimating the affine geometry, a process to find a special plane in the projective space by means of vanishing points. The third step, which includes camera self-calibration, is obtaining a metric geometry from which a 3D model of the scene could be obtained. The major advantage of this method is that the stereo images do not need to be calibrated for reconstruction. The results of camera calibration and reconstruction have shown the possibility of obtaining a 3D model directly from features in the images.

• Journal of Cadastre & Land InformatiX
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• v.47 no.1
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• pp.95-110
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• 2017

The network RTK surveying has been widely used in the field of cadastral surveys in recent years, and its use is gradually expanding. As a result of the implementation of GPS static surveys by civilian companies in accordance with the progress of the cadastral surveys and gradual civilian transfer plans and cadastral surveys, there has been an increase in the number of civilian companies performing surveys. In this paper, we describe the process of applying the results of analysis of conformity using the network RTK site calibration function on the local coordinate system to the GPS static surveying of the cadastral reference points in Anyang city. In addition, the measurement results of the network RTK site calibration function and the results of the GPS static surveying network reconciliation in the local coordinate system were compared, and the performance was determined within 0.04m maximum of RMSE(Root Mean Square Error), and further study on the application method is needed.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.5
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• pp.347-356
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• 2003

Camera pose and scene geometry estimation from video sequences is widely used in various areas such as image composition. Structure and motion recovery based on the auto calibration algorithm can insert synthetic 3D objects in real but un modeled scenes and create their views from the camera positions. However, most previous methods require bundle adjustment or non linear minimization process [or more precise results. This paper presents a new auto' calibration algorithm for video sequence based on two steps: the one is key frame selection, and the other removes the key frame with inaccurate camera matrix based on an absolute quadric estimation by LMedS. In the experimental results, we have demonstrated that the proposed method can achieve a precise camera pose estimation and scene geometry recovery without bundle adjustment. In addition, virtual objects have been inserted in the real images by using the camera trajectories.

• Journal of IKEEE
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• v.24 no.3
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• pp.719-726
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• 2020

A threshold-voltage sensing circuit is proposed to compensate for pixel aging in active matrix organic light-emitting diodes. The proposed threshold-voltage sensing circuit consists of sample-hold (S/H) circuits and a single-ended successive approximation register (SAR) analog-to-digital converter (ADC) with a resolution of 10 bits. To remove a scale down converter of each S/H circuit and a voltage gain amplifier with a signl-to-differentail converter, the middle reference voltage calibration and input range calibration for the single-ended SAR ADC are performed in the capacitor digital-to-analog converter and reference driver. The proposed threshold-voltage sensing circuit is designed by using a 180-nm CMOS process with a supply voltage of 1.8 V. The ENOB and power consimption of the single-ended SAR ADC are 9.425 bit and 2.83 mW, respectively.

• Journal of Korean Society on Water Environment
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• v.29 no.5
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• pp.681-690
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• 2013

Watershed models have been increasingly used to support an integrated management of land and water, non-point source pollutants, and implement total daily maximum load policy. However, these models demand a great amount of input data, process parameters, a proper calibration, and sometimes result in significant uncertainty in the simulation results. For this reason, uncertainty analysis is necessary to minimize the risk in the use of the models for an important decision making. The objectives of this study were to evaluate three different uncertainty analysis algorithms (SUFI-2: Sequential Uncertainty Fitting-Ver.2, GLUE: Generalized Likelihood Uncertainty Estimation, ParaSol: Parameter Solution) that used to analyze the sensitivity of the SWAT(Soil and Water Assessment Tool) parameters and auto-calibration in a watershed, evaluate the uncertainties on the simulations of runoff and sediment load, and suggest alternatives to reduce the uncertainty. The results confirmed that the parameters which are most sensitive to runoff and sediment simulations were consistent in three algorithms although the order of importance is slightly different. In addition, there was no significant difference in the performance of auto-calibration results for runoff simulations. On the other hand, sediment calibration results showed less modeling efficiency compared to runoff simulations, which is probably due to the lack of measurement data. It is obvious that the parameter uncertainty in the sediment simulation is much grater than that in the runoff simulation. To decrease the uncertainty of SWAT simulations, it is recommended to estimate feasible ranges of model parameters, and obtain sufficient and reliable measurement data for the study site.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.3
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• pp.274-286
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• 2016

This paper presents a 4-channel multi-rate vertical-cavity surface-emitting laser (VCSEL) driver. In order to keep the output power constant with respect to the process, voltage, temperature (PVT) variations, this research proposes automatic power and magnitude. For the fast settling time, the high-speed 10-bit time-interleaved Flash-successive approximation analog to digital converter (Flash-SAR ADC) is proposed and shared for automatic power and magnitude calibration to reduce the die area and power consumption. This chip is fabricated using $0.13-{\mu}m$ CMOS technology and the die area is $4.2mm^2$. The power consumption is 117.84 mW per channel from a 3.3 V supply voltage at 10 Gbps. The measured resolution of bias /modulation current for APC/AMC is 0.015 mA.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.2
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• pp.87-93
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• 2010

This paper presents a low-power, wide tuning range VCO with automatic two-step negative-Gm calibration loop to compensate for the process, voltage and temperature variation. To cover the wide tuning range, digital automatic negative-Gm tuning loop and analog automatic amplitude calibration loop are used. Adaptive body biasing (ABB) technique is also adopted to minimize the power consumption by lowering the threshold voltage of transistors in the negative-Gm core. The power consumption is 2 mA to 6mA from a 1.2 V supply. The VCO tuning range is 2.65 GHz, from 2.35 GHz to 5 GHz. And the phase noise is -117 dBc/Hz at the 1 MHz offset when the center frequency is 3.2 GHz.

• Journal of IKEEE
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• v.26 no.4
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• pp.659-670
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• 2022

An 830-Mb/s/pin transceiver for a controller supporting ×32 LPDDR2 memory is designed. The transmitter consists of eight unit circuits has an impedance in the range of 34Ω ∽ 240Ω, and its impedance is controlled by an impedance correction circuit. The transmitted DQS signal has a phase shifted by 90° compared to the DQ signals. In the receive operation, the read time calibration is performed by per-pin skew calibration and clock-domain crossing within a byte. The implemented transceiver for the LPDDR2 memory controller is designed by using a 55-nm process using a 1.2V supply voltage and has a maximum signal transmission rate of 830 Mb/s/pin. The area and power consumption of each lane are 0.664 mm² and 22.3 mW, respectively.