• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1067-1070
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• 2006

We have demonstrated highly efficient WOLED with two separated emissive layers using a blue fluorescent dye and a red phosphorescent dye. The maximum luminous efficiency of the device was 11.2 cd/A at $20\;mA/cm^2$ and $CIE_{x,y}$ coordinates varied from (x = 0.33, y = 0.37) at 6V to (x = 0.25, y = 0.33) at 14V.

• Journal of Biosystems Engineering
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• v.26 no.3
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• pp.287-294
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• 2001

The geometrical and physical properties of red peppers were studied for proper design of a red pepper processor. Mass, volume, roundness and compactness of red peppers were calculated from digital images. They were compared with real data and the relations of them were suggested. Roundness of red peppers was ranged from 0.2 to 0.5 and the average value was 0.349. Compactness of red peppers was ranged from 25 to 50 and the average value was 37.1. The regression equations to calculate the volume and mass of red pepper were obtained as y$\_$v/$\_$=/0.553$\varkappa$$_1$+1.441$\varkappa$$_2$-1.013$\varkappa$$_3$(R=0.95) and y$\_$m/=0.252$\varkappa$$_1$+0.938$\varkappa$$_2$-0.499$\varkappa$$_3$-1.5112 (R=0.93), y$\_$v/:volume(㎤), y$\_$m/:mass(g), $\varkappa$$_1$: perimeter(cm), $\varkappa$$_2$: area(㎠), $\varkappa$$_3$: length of major axis(cm), respectively. The direction for aligning the red pepper in a machine processing was easily and perfectly recognized. The response time for digital image processing has to be reduced for more efficient operation. HSI and YIQ values could be useful for recognizing the red pepper from background.

• Journal of Preventive Medicine and Public Health
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• v.20 no.2 s.22
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• pp.255-260
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• 1987

The digital dust indicator (Sibata P-5), one of the direct·reading instruments was evaluated for the respirable dust in the underground coal mine environments. As a reference, respirable dust was determined using three cyclones and/or impactors. All the tests were performed on aerosol in twenty underground coal mines. The coefficients of mass-relative concentration were $0.067{\pm}0.054$ (Mean$\pm$Standard deviation) (range: 0.006-0.172). The relationship between relative concentration and temperature was not significant statistically. Also, the relationship of relative concentration and relative humidity was not significant. Mass concentration and relative concentration were $5.31{\pm}5.22mg/m^3$ and $162{\pm}163$ CPM ($Mean{\pm}Standard$ deviation) respectively. The range of mass concentration was $1.22-22.69mg/m^3$; relative concentration 16-628 CPM. The relationship of mass concentration and relative concentration was not significant in these ranges.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.423-425
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• 2005

Reflective paper-like display (PLD) using two types of particles having different electric polarity has been developed. A positive-charged particle has $TiO_2$, polymer and charge control agent (CCA), while a negative-charged particle consists of carbon black, polymer and CCA. We achieved fast response time (${\sim}0.2$ msec) and passive matrix driving addressing. These methods can easily be adapted to complete a large area display and flexible display.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.22 no.2
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• pp.273-282
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• 1992

The purpose of this study was to propose the utility which was evaluated the digital image processing and clinical application of the videodensitomery. The experiments were performed with IBM-PC/16bit-AT compatible, video camera(CCdtr55, Sony Co., Japan), an color monitor(MultiSync 3D, NEC, Japan) providing the resolution of 512×480 and 64 levels of gray. Sylvia Image Capture Board for the ADC(analog to digital converter) was used, composed of digitized image from digital signal and the radiographic density was measured by 256 level of gray. The periapical radiograph(Ektaspeed EP-21, Kodak Co., U. S. A) which was radiographed dried human mandible by exposure condition of 70 kVp and 48 impulses, was used for primary X-ray detector. And them evaluated for digitzed image by low and high pass filtering, correlations between aluminum equivalent values and the thickness of aluminum step wedge, aluminum equivalent values of sound enamel, dentin, and alveolar bone, the range of diffuse density for gray level ranging from 0 to 255. The obtained results were as follows: 1. The edge between aluminum steps of digitized image were somewhat blurred by low pass filtering, but edge enhancement could be resulted by high pass filtering. Expecially, edge enhancement between distal root of lower left 2nd molar and alveolar lamina dura was observed. 2. The correlation between aluminum equivalent values and the thickness of aluminum step wedge was intimated, yielding the coefficient of correlation r=0.9997(p<0.00l), the regression line was described by Y=0.9699X+0.456, and coefficient of variation amounting to 1.5%. 3. The aluminum equivalent values of sound enamel, dentin, and alvolar bone were 15.41㎜, 12.48㎜, 10.35㎜, respectively. 4. The range of diffuse density for gray level ranging from 0 to 255 was wider enough than that of photodenstiometer to be within the range of 1-4.9.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.5
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• pp.473-481
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• 2013

A fractional folding analog-to-digital converter (ADC) with a novel arithmetic digital encoding technique is discussed. In order to reduce the asymmetry errors of the boundary conditions for the conventional folding ADC, a structure using an odd number of folding blocks and fractional folding rate is proposed. To implement the fractional technique, a new arithmetic digital encoding technique composed of a memory and an adder is described. Further, the coding errors generated by device mismatching and other external factors are minimized, since an iterating offset self-calibration technique is adopted with a digital error correction logic. A prototype 8-bit 1GS/s ADC has been fabricated using an 1.2V 0.13 um 1-poly 6-metal CMOS process. The effective chip area is $2.1mm^2$(ADC core : $1.4mm^2$, calibration engine : $0.7mm^2$), and the power consumption is 88 mW. The measured SNDR is 46.22 dB at the conversion rate of 1 GS/s. Both values of INL and DNL are within 1 LSB.

• Journal of Digital Convergence
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• v.11 no.5
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• pp.319-324
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• 2013

The purpose of the study was to evaluation of the knee lateral collateral ligament (LCL) stability of normal males and females in twenties by using digital telometer. The volunteer subjects agreed the research goal and were 31 normal adults(16 male: $21.1{\pm}1.5$ years, 15 female: $21.2{\pm}1.2$ years) who have not got any illness regarding their knee. X-ray images were taken varus stress on medial femorotibial joint space using by digital telometer, and grade of pain was surveyed. We measured the joint space width (JSW) in the digital radiology. As a result, the JSW of male group were $5.60{\pm}0.76$ mm and JSW of female group were $5.05{\pm}0.55$ mm (p=0.022) on the neutral state of the knee. Based on the result of varus stress on the knee, female group showed much widen than male group but it was not significant difference (p>0.05). When increased varus stress on the knee, all groups were felt pain from 17 daN to 19 daN. The result could be valuable when the varus stress on the LCL by using the digital telometer.

• Journal of Korean society of Dental Hygiene
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• v.13 no.6
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• pp.909-916
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• 2013

Objectives : The purpose of this study was to investigate the perceptions of dental hygienists toward digital dentistry. Methods : The subjects were 393 dental hygienists in Daegu Gyeongbuk. A total of 380 data were analyzed except the incomplete questionnaires. Data were analyzed by descriptive statistics, chi-square test, t-test, one-way ANOVA using SPSS version 18.0. Results : 1. Difference of perception by general characteristics was affected by age, academic background, working career, and married. 2. Difference of perception by utilization of digital facilities was affected by digital camera, CAD/CAM system, oral scanner, and computer system. 3. Difference of perception by digital education experience and intention of participation was affected by stronger intention to participate in digital education and practical exercise. Digital X-ray system and CAD/CAM system were the must-be equipment in education. Conclusions : Utilization of digital dentistry is the motive for education experience in dental hygienists.

• ETRI Journal
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• v.37 no.5
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• pp.961-971
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• 2015

This paper proposes a 250 mV supply voltage digital low-dropout (LDO) regulator. The proposed LDO regulator reduces the supply voltage to 250 mV by implementing with all digital circuits in a$0.11{\mu}m$ CMOS process. The fast current tracking scheme achieves the fast settling time of the output voltage by eliminating the ringing problem. The over-voltage and under-voltage detection circuits decrease the overshoot and undershoot voltages by changing the switch array current rapidly. The switch bias circuit reduces the size of the current switch array to 1/3, which applies a forward body bias voltage at low supply voltage. The fabricated LDO regulator worked at 0.25 V to 1.2 V supply voltage. It achieved 250 mV supply voltage and 220 mV output voltage with 99.5% current efficiency and 8 mV ripple voltage at $20{\mu}A$ to $200{\mu}A$ load current.

• Imaging Science in Dentistry
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• v.41 no.1
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• pp.7-10
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• 2011

Purpose : The purpose of this study was to compare the conventional and digital radiography in the estimation of working length in mandibular molars. Materials and Methods : Sixty molar teeth were selected and divided into three groups in the basis of canal curves (0-$15^{\circ}$, 15-$30^{\circ}$, > $30^{\circ}$). After the placement of a 15 K-file, radiographs were taken with a conventional film (Fspeed) and a digital sensor. Canal lengths were measured in these images by two observers. Statistical analysis was performed with repeated measures of ANOVA and paired sample t-test with 95% confidence. Results : There was a high inter-observer agreement on the measurements of working length in conventional and digital radiographs. There was no significant difference between the mean values of measurements in conventional and digital radiography. Moreover, there was no significant difference between conventional and digital radiography with the actual values in the basis of canal curves. Conclusion : The accuracy of conventional and digital radiography in the determination of the working length was in an acceptable range.