• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.51-54
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• 2008

In this paper, we propose a practical method for displaying 2D/True3D mixed contents in real-time. Many companies released their 3D display recently, but the costs of producing True3D contents are still very expensive. Since there are already a lot of 2D contents in the world and it is more effective to mix True3D objects into the 2D contents than making True3D contents directly, people became interested in mixing 2D/True3D contents. Moreover, real-time 2D/True3D mixing is helpful for 3D displays because the scenario of the contents can be easily changed on playback-time by adjusting the 3D effects and the motion of the True3D object interactively. In our system, True3D objects are rendered into multiple view-point images, which are composed with 2D contents by using depth information, and then they are multiplexed with pre-generated view masks. All the processes are performed on a graphics processor. We were still able to play a 2D/True3D mixed contents with Full HD resolution in real-time using a normal graphics processor.

• Journal of the Optical Society of Korea
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• v.18 no.4
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• pp.406-413
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• 2014

An optical true-time delay beam-forming system using a tunable dispersion compensating module (DCM) for dense-wavelength division modulation (DWDM) and a multiwavelength fiber ring laser for a phased array antenna is proposed. The multiwavelength fiber ring laser has one output that includes four wavelengths; and four outputs that include only single-wavelength. The advantage of such a multiwavelength fiber ring laser is that it minimizes the number of devices in the phased array antenna system. The time delays according to wavelengths, which are assigned for each antenna element, are obtained from the tunable DCM. The tunable DCM based on a temperature adjustable Fabry-Perot etalon is used. As an experimental result, a DCM could be used to obtain the change of the beam angle by adjusting the dispersion value of the DCM at the fixed lasing wavelengths of the fiber ring laser in the proposed optical true-time delay.

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.44-44
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• 2003

To determine feasibility of contrast-enhanced MRI (co-MRI) at true end-diastole (ED) free from limitation of time for inversion-recovery and trigger window for quantifying transmural extent of infarction. 대상 및 방법： MRI was performed in 18 patients with myocardial infarction. Cine imaging and co-MRI with same registered slices in short axis were peformed. To allow true ED co-MRI, ECG synchronization should use two RR-intervals for one acquisition of a segment of k-space by setting the heart rate to half that of the true heart rate. Trigger delay time was adjusted to the RR-interval for imaging at ED and to the sum of RR-interval plus the time between R-wave and the end-systole (ES) determined in cine images for imaging at ES.

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.91-91
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• 2003

To determine feasibility of contrast-enhanced MRI (co-MRI) at true end-diastole (ED) free from limitation of time for inversion-recovery and trigger window for quantifying transmural extent of infarction. 대상 및 방법： MRI was peformed in 18 patients with myocardial infarction. Cine imaging and co-MRI with same registered slices in short axis were performed. To allow true ED co-MRI, ECG synchronization should use two RR-intervals for one acquisition of a segment of k-space by setting the heart rate to half that of the true heart rate. Trigger delay time was adjusted to the RR-interval for imaging at ED and to the sum of RR-interval plus the time between R-wave and the end-systole (ES) determined in cine images for imaging at ES.

• Industry Promotion Research
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• v.8 no.3
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• pp.137-152
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• 2023

As the world progresses towards a global society as time goes by, it is a natural reality that interpreting the fortunes of people born in foreign countries will inevitably increase in the future. If the time of birth is different, a big problem arises in the theory of MyungLiollgy. Therefore, this researcher decides whether to use the local standard time of the country of birth or convert it to the Korean time zone when a foreign-born person writes four weeks, because the position of the sun determines the time and date, so the local standard time It was concluded that it was appropriate to use it, and to support the discussion on the correction of true solar time in Eastern and Western countries, we carefully selected major countries and major cities where the time difference between the currently used national standard time and the true solar time according to the actual longitude line was expected, and the results were presented. was calculated and derived. As a result of the study, it was confirmed that the time difference between the national standard time and the true solar time is much greater than the general idea. On the other hand, through the case of actual foreign-born people, it was possible to find out the great influence of summer time on the composition of the sandbar, in addition to the influence of the exact time difference on the birth date and cutting time. Through the results of this study, it is thought that we have laid the systematic foundation of the myo-logical theory on the correction of true solar time in Eastern and Western countries for the simplicity of the four weeks of foreign-born people, and this will serve as an opportunity to reduce confusion about the method of simplifying the four weeks of foreign-born people. It is assumed that it will be possible.

• Korean Journal of Optics and Photonics
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• v.17 no.1
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• pp.7-17
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• 2006

In this paper, we proposed an optical true time-delay (TTD) for planar phased array antennas (PAAs), which is composed of a wavelength-dependent optical true time delay (WDOTTD) followed by a wavelength-independent optical true time delay (WIOTTD). The WDOTTD is a fiber Bragg gratings (FBGs) Prism and the WDOTTD is a fiber delay-lines matrix of which each component consists of a certain length of fiber connected to cross-ports of a 2${\times}$2 MEMS switch. A 10-GHz 2-bit${\times}$4-bit two-dimensional optical TTD has been fabricated by cascading a WDOTTD with a maximum time delay of 810 ps to a WIOTTD of $\pm$50 ps. Time delay and insertion loss for each radiation angle have been measured. Time delay error for the WIOTTD has been measured to be less than $\pm$1 ps. We have also designed a two-dimensional 10-GHz PAA composed of 8${\times}$8 microstrip patch antenna elements driven by the proposed TTD. The radiation patterns of this PAA have been obtained by simulation and analyzed.

• Korean Journal of Optics and Photonics
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• v.18 no.2
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• pp.162-166
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• 2007

In this paper, we propose a WDM optical true time-delay (OTTD) beam former for phased way antenna (PAA) systems. It is composed of a delay lines matrix and a multiwavelength source with discrete DFB laser diodes. The building block of a delay lines matrix is a $2\times2$ optical MEMS switch with proper fiber-optic delay line connected between cross ports. A $4\times3$ matrix using four DFB lasers has been fabricated with unit time-delay difference of 12 ps. Maximum time-delay error was measured to be -1.74 ps and +1.14 ps at a radiation angle of $46.05^{\circ}$, corresponding to error range of $-2.87^{\circ}\sim+1.88^{\circ}$. By measuring time-delays at six different RF frequencies from 5- to 10-GHz, we verified the true time-delay characteristic of our OTTD.

• Journal of the Korea Society for Simulation
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• v.11 no.3
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• pp.35-48
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• 2002

In the work presented here, we describe a method to extract TrueType features for supporting letter recognition. Even if variously existing document processing techniques have been challenged, almost few methods are capable of recognize a letter associated with its TrueType features supporting OCR free, which boost up fast processing time for image text retrieval. By reviewing the mechanism generating digital fonts and birth of TrueType, we realize that each TrueType is drawn by its contour of the glyph table. Hence, we are capable of deriving the segment with density for a letter with a specific TrueType, defined by the number of occurrence over a segment width. A certain number of occurrence appears frequently often due to the fixed segment width. We utilize letter recognition by comparing TrueType feature library of a letter with that from input word images. Experiments have been carried out to justify robustness of the proposed method showing acceptable results.

• Journal of Bio-Environment Control
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• v.13 no.1
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• pp.21-25
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• 2004

This experiment was carried out to investigate the effect of apex removal at different leaf ages on the growth and yield of broccoli in pinching cultivation. Apex was pinched when 2, 3 or 4 true leaves were spread during nursery bed, and non-pinching was conventional method. The plant height was not different among treatments but the fresh weight was decreased as the pinching days were delayed. The numbers of leaves and lateral shoots were increased compared to those of non-pinching by pinching. Days to central budding were shortended by 3 days when pinched at 2 true leaves spreading stage than those of non-pinching. Central (1st) head weight was heaviest when pinched at the time of 2 true leaves spreading (157g). Total head weight was heaviest when pinched at the time of 2 true leaves spreading (378g), and lowest at 4 true leaves spreading stage (196g). Marketable yields were increased by 48% when pinched at the time of 2 true leaves spreading (1,754kg) as compared with those of non-pinching (1,184kg) and lowest when pinched at the time of 4 true leaves spreading (820kg). Also, first harvest was shortended by 6 days by pinching at 2 true leaves spreading stage.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.3
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• pp.193-197
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• 2013

This paper presents a 5-bit true time delay circuit using a standard 0.18 ${\mu}m$ CMOS process for the broadband phased array antenna without the beam squint. The maximum time delay of ~106 ps with the delay step of ~3.3 ps is achieved at 5-20 GHz. The RMS group delay and amplitude errors are < 1 ps and <2 dB, respectively. The measured insertion loss is <27 dB and the input and output return losses are <12 dB at 5-15 GHz. The current consumption is nearly zero with 1.8 V supply. The chip size is $1.04{\times}0.85\;mm^2$ including pads.