• Korean Journal of Radiology
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• v.25 no.3
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• pp.267-276
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• 2024

Objective: To evaluate the diagnostic performance of susceptibility map-weighted imaging (SMwI) taken in different acquisition planes for discriminating patients with neurodegenerative parkinsonism from those without. Materials and Methods: This retrospective, observational, single-institution study enrolled consecutive patients who visited movement disorder clinics and underwent brain MRI and ¹⁸F-FP-CIT PET between September 2021 and December 2021. SMwI images were acquired in both the oblique (perpendicular to the midbrain) and the anterior commissure-posterior commissure (AC-PC) planes. Hyperintensity in the substantia nigra was determined by two neuroradiologists. ¹⁸F-FP-CIT PET was used as the reference standard. Inter-rater agreement was assessed using Cohen;s kappa coefficient. The diagnostic performance of SMwI in the two planes was analyzed separately for the right and left substantia nigra. Multivariable logistic regression analysis with generalized estimating equations was applied to compare the diagnostic performance of the two planes. Results: In total, 194 patients were included, of whom 105 and 103 had positive results on ¹⁸F-FP-CIT PET in the left and right substantia nigra, respectively. Good inter-rater agreement in the oblique (κ = 0.772/0.658 for left/right) and AC-PC planes (0.730/0.741 for left/right) was confirmed. The pooled sensitivities for two readers were 86.4% (178/206, left) and 83.3% (175/210, right) in the oblique plane and 87.4% (180/206, left) and 87.6% (184/210, right) in the AC-PC plane. The pooled specificities for two readers were 83.5% (152/182, left) and 82.0% (146/178, right) in the oblique plane, and 83.5% (152/182, left) and 86.0% (153/178, right) in the AC-PC plane. There were no significant differences in the diagnostic performance between the two planes (P > 0.05). Conclusion: There are no significant difference in the diagnostic performance of SMwI performed in the oblique and AC-PC plane in discriminating patients with parkinsonism from those without. This finding affirms that each institution may choose the imaging plane for SMwI according to their clinical settings.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.4
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• pp.386-408
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• 1988

A study was conducted to develop a model for estimating evapotranspiration and yield of Chinese cabbages from meteorological factors from 1981 to 1986 in Suweon, Korea. Lysimeters with water table maintained at 50cm depth were used to measure the potential evapotranspiration and the maximum evapotranspiration in situ. The actual evapotranspiration and the yield were measured in the field plots irrigated with different soil moisture regimes of -0.2, -0.5, and -1.0 bars, respectively. The soil water content throughout the profile was monitored by a neutron moisture depth gauge and the soil water potentials were measured using gypsum block and tensiometer. The fresh weight of Chinese cabbages at harvest was measured as yield. The data collected in situ were analyzed to obtain parameters related to modeling. The results were summarized as followings: 1. The 5-year mean of potential evapotranspiration (PET) gradually increased from 2.38 mm/day in early April to 3.98 mm/day in mid-June, and thereafter, decreased to 1.06 mm/day in mid-November. The estimated PET by Penman, Radiation or Blanney-Criddle methods were overestimated in comparison with the measured PET, while those by Pan-evaporation method were underestimated. The correlation between the estimated and the measured PET, however, showed high significance except for July and August by Blanney-Criddle method, which implied that the coefficients should be adjusted to the Korean conditions. 2. The meteorological factors which showed hgih correlation with the measured PET were temperature, vapour pressure deficit, sunshine hours, solar radiation and pan-evaporation. Several multiple regression equations using meteorological factors were formulated to estimate PET. The equation with pan-evaporation (Eo) was the simplest but highly accurate. PET = 0.712 + 0.705Eo 3. The crop coefficient of Chinese cabbages (Kc), the ratio of the maximum evapotranspiration (ETm) to PET, ranged from 0.5 to 0.7 at early growth stage and from 0.9 to 1.2 at mid and late growth stages. The regression equation with respect to the growth progress degree (G), ranging from 0.0 at transplanting day to 1.0 at the harvesting day, were: $$Kc=0.598+0.959G-0.501G^2$$ for spring cabbages $$Kc=0.402+1.887G-1.432G^2$$ for autumn cabbages 4. The soil factor (Kf), the ratio of the actual evapotranspiration to the maximum evapotranspiration, showed 1.0 when the available soil water fraction (f) was higher than a threshold value (fp) and decreased linearly with decreasing f below fp. The relationships were: Kf=1.0 for $$f{\geq}fp$$ Kf=a+bf for f$$I{\leq}Esm$$ Es = Esm for I > Esm 6. The model for estimating actual evapotranspiration (ETa) was based on the water balance neglecting capillary rise as: ETa=PET. Kc. Kf+Es 7. The model for estimating relative yield (Y/Ym) was selected among the regression equations with the measured ETa as: Y/Ym=a+bln(ETa) The coefficients and b were 0.07 and 0.73 for spring Chinese cabbages and 0.37 and 0.66 for autumn Chinese cabbages, respectively. 8. The estimated ETa and Y/Ym were compared with the measured values to verify the model established above. The estimated ETa showed disparities within 0.29mm/day for spring Chinese cabbages and 0.19mm/day for autumn Chinese cabbages. The average deviation of the estimated relative yield were 0.14 and 0.09, respectively. 9. The deviations between the estimated values by the model and the actual values obtained from three cropping field experiments after the completion of the model calibration were within reasonable confidence range. Therefore, this model was validated to be used in practical purpose.

• Polymer(Korea)
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• v.38 no.4
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• pp.411-416
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• 2014

Due to the polar characteristics of silica compared to carbon black, the degree of silica dispersion, which affects the mechanical properties of rubber compounds, is an important issue. Wolff first introduced the in-rubber structure of particles (${\alpha}_F$) to express the structure development in the compounds; however, with the introduction of bifunctional silanes, his theory could not explain the 3-dimensional network structure of the compounds. Later his theory was expanded to express the composite interaction parameter (in-rubber structure of the compound) (${\alpha}_C$), which included Wolff's filler-filler interaction parameter (${\alpha}_F$), however, there was no reported experimental result proving the theory. This research first experimentally expressed the in-rubber structure of the compound ${\alpha}_C$ (= ${\alpha}_F+{\alpha}_{FP}$(filler-silane-rubber interaction parameter) + ${\alpha}_P$ (rubber-rubber interaction parameter)) upon mono- and bifunctional silane treated silica filled natural rubber (NR) compounds. Using different structure silanes, i.e. PTES, OTES, TESPD, and TESPT, the ${\alpha}_C$ value of each compound was measured and calculated. The ${\alpha}_C$ value of TESPT treated silica filled compound was 1.64, which composed of ${\alpha}_F$ (0.99), ${\alpha}_{FP}$ (0.31), and ${\alpha}_P$ (0.34).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2793-2800
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• 2011

The purpose of this research is to develop and optimize a lane departure warning application based on a smartphone which can be applicable as a new platform for various mobile information applications. Recently, a lane detection warning system which is a representative application among safe driving assistant solutions is being commercialized. Due to the necessity of powerful embedded hardware platform and its price, its market is still not growing. In this research, it is proposed to develop and optimize a lane departure warning application on iPhone 3GS. OpenCV is used for efficient image processing, and for lane detection a heuristic algorithm based on Hough Transform is proposed. The application was developed under Macintosh PC platform with Xcode 3.2.4 development tools, downloaded to the iPhone and has been tested on the real paved road. The experimental result has shown that the detection ratio of the straight lane was over 90% and the processing speed was 1.52fps. For the enhancement of the speed, a few optimization methods were introduced and the fastest speed was 3.84fps. Through the improvement of lane detection algorithm, additional optimization works and the adoption of a new powerful platform, it will be successfully commercialized on smartphone application market.

• 대한핵의학회:학술대회논문집
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• 2005.11a
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• pp.347.1-347.1
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• 2005

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2177-2178
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• 2006

학습 행동에서의 뇌파 측정은 실시간으로 두뇌 기능 상태를 연구하는데 유용한 연구 방법이며 대뇌의 부위 중 전두엽은 새로움에 대한 지향 반응과 사고 활동에 중요한 역할을 한다. 본 연구에서는 중학교 2학년 학생에게 새로운 시청각 학습 자료를 제시하고 5회의 반복학습이 이루어지는 과정에서의 전두부($Fp_2,Fp_2$)의 뇌파를 측정하고 Fourier, Wavelet 변환을 하여 정량적으로 분석하였다. 주의 집중, 정서 등 인지와 관련지어 특정파의 조절 능력 및 파의 특성을 이용한 여러 연구들을 종합해보면, 기억력, 주의지속과 연관되어 알파파, 베타파와 세타파가 발생되는 것을 볼 수 있다. 이 중 알파파는 기존의 뇌 상태를 동기화시키고 주의나 기억의 과정에 영향을 미칠 수 있는 것으로 증명되었다. 본 논문에서는 신호 처리에 높은 효율을 보이는 Wavelet 변환을 이용하여, 학습이 됨에 따라 변화하는 EEG 신호 가운데 알파파의 패턴과 활성도를 분석하고자 한다.

• The Korean Journal of Nuclear Medicine
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• v.39 no.6
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• pp.445-455
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• 2005

Purpose: We developed an animal SPECT system using clinical Philips ARGUS scintillation camera and pinhole collimator with specially manufactured small apertures. In this study, we evaluated the physical characteristics of this system and biological feasibility for animal experiments. Materials and Methods: Rotating station for small animals using a step motor and operating software were developed. Pinhole inserts with small apertures (diameter of 0.5, 1.0, and 2.0 mm) were manufactured and physical parameters including planar spatial resolution and sensitivity and reconstructed resolution were measured for some apertures. In order to measure the size of the usable field of view according to the distance from the focal point, manufactured multiple line sources separated with the same distance were scanned and numbers of lines within the field of view were counted. Using a Tc-99m line source with 0.5 mm diameter and 12 mm length placed in the exact center of field of view, planar spatial resolution according to the distance was measured. Calibration factor to obtain FWHM values in 'mm' unit was calculated from the planar image of two separated line sources. Te-99m point source with i mm diameter was used for the measurement of system sensitivity. In addition, SPECT data of micro phantom with cold and hot line inserts and rat brain after intravenous injection of [I-123]FP-CIT were acquired and reconstructed using filtered back protection reconstruction algorithm for pinhole collimator. Results: Size of usable field of view was proportional to the distance from the focal point and their relationship could be fitted into a linear equation (y=1.4x+0.5, x: distance). System sensitivity and planar spatial resolution at 3 cm measured using 1.0 mm aperture was 71 cps/MBq and 1.24 mm, respectively. In the SPECT image of rat brain with [I-123]FP-CIT acquired using 1.0 mm aperture, the distribution of dopamine transporter in the striatum was well identified in each hemisphere. Conclusion: We verified that this new animal SPECT system with the Phlilps ARGUS scanner and small apertures had sufficient performance for small animal imaging.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.97-99
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• 2011

본 논문에서는 안전주행지원 솔루션인 스마트폰용 차선이탈경보 애플리케이션의 실행 속도 향상 방법을 연구하였다. 이전 연구에서 스마트폰(iPhone 3GS) 기반의 차선이탈경보 어플리케이션을 개발하였는데 입력 영상의 처리 속도가 1.52fps였다. 본 연구에서는 영상 처리 속도를 향상시키기 위한 최적화 작업을 진행하였으며 기존의 차선이탈경보 어플리케이션의 차선인식 속도보다 프레임당 평균 0.4초 정도 단축되어 약 4fps 속도로 성능을 보였다. 향후 추가 연구를 통해 처리 속도를 좀 더 향상시킬 것이다.

• Journal of the Korean Society for Nondestructive Testing
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• v.19 no.6
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• pp.411-419
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• 1999

It has been well recognized that a long term service at elevated temperature of $350^{\circ}C{\sim}550^{\circ}C$ induces embrittlement damage due to carbide precipitation and/or P, Sb and Sn segregation at grain boundaries and thereby deteriorates the grain boundary strength of heat resisting components in the energy-related plants. Therefore, it is very important to assess quantitatively the extent of embrittlement damage of heat resisting components to secure the reliable and efficient service condition and to prevent brittle failure in service. However, because fracture tests are limited in size and number of specimen obtained from the structural components, nondestructive test method is required. In this study, the optimum electrochemical parameters are investigated and discussed to evaluate nondestructive embrittlement damage for aged 2.25Cr-1Mo steels by means of electrochemical polarization test method (ECPTM) in proper corrosive environment. In addition, the electrochemical test results are compared with embrittlement degree evaluated by semi-nondestructive SP test.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.2
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• pp.133-140
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• 1999

This pot experiment was conducted to find out the forage productivity and quality in a grass/clover sward as affected by the application of three different fertilizers; double superphosphate(DS), fused Mg-phosphate(FP), and complex fertilizer(CF), on newly reclaimed hilly soil. This 1st part was concerned with the forage yields, yield components and botanical composition. The results obtained are summarized as follows: 1. The significant differences in the yields(relative yields, %) of whole forages and legume were laid in the following increasing order; CF(relative yield: 150.4% in whole forages and 169.7% in ladino clover) > FP(125.4% in whole forages and 121.7% in ladino clover) > DS(100.0%). The yield of orchardgrass was significantly reduced in the DS plot, compared with the yields in the FP and CF plots, whereas these showed no significant differences between the FP and CF plots. 2. In the botanicl composition, it showed that the rates of grass : legume were 48:52% in the DS and FP, and 40:60% in the CF. It was recognized that the application of complex fertilizer contributed to the increasing of the yields of whole forages, and especially legume yield and rate in the mixed sward.