• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.3
• /
• pp.91-98
• /
• 2015

As one of solutions to obtain efficient use of limited spectrum resource, we suggest a methodology for the co-channel multi-site radar operations with a shifted linear frequency modulation (SLFM) based on GPS clock. The proposed algorithm is that we find a candidate set of SLFM signals with the minimum acceptable level of the correlation from the cross-correlation characteristics among selected SLFM signals. To verify the proposed methodology, numerical analysis has been accomplished for several radars operating in the same channel with a sawtooth or triangle LFM signal. The computational results of detected distances as well as range profiles are also examined for interference, noise, and algorithm limitation including the error of clock synchronization.

• The Bulletin of The Korean Astronomical Society
• /
• v.40 no.1
• /
• pp.46.4-47
• /
• 2015

Carnegie Hubble Program II (hereafter CHP II) is a large Hubble Space Telescope (HST) observing campaign in the cycle 22 composed of a total of 184 orbits (132 primes + 52 parallels), which aims to measure H0 directly with an unprecedented accuracy. Unlike our previous efforts in CHP I which used Cepheids as a yardstick, CHP II takes the Population II (Pop II) distance indicators such as RR Lyraes and tip of the red giant branch stars (TRGBs) to set up a new calibration to Type Ia supernovae (SN Ia) distance. The Pop II distance scales have two immediate advantages over the classical Cepheid method: 1) The period-luminosity relation of the RR Lyrae has a scatter that is a factor of 2 smaller; 2) The RR Lyrae/TRGB distance scale can be applied to both elliptical and spiral galaxies. This will provide a great systematic benefit by ultimately allowing us to double the number of SN Ia distances based on geometry. By taking advantage of this Pop II route, we expect to measure H0 value to 3 % of error which will be the highest accuracy H0 measurement to date using the "Distance Ladder" method. In this talk I will present a brief background/overview on the CHP II, observations/data acquisition status, and ongoing research progress/preliminary results.

• Animal cells and systems
• /
• v.16 no.6
• /
• pp.488-497
• /
• 2012

A DNA barcode based on 648 bp of cytochrome c oxidase I (COI) gene aims to build species-specific libraries for animal groups. However, it is hard to recover full-length (648 bp) barcode gene from environmental fecal samples due to DNA degradation. In this study, we designed a new primer set (K_Bird), which amplifies a 226 bp fragment targeted an inner position of full-length COI barcode based on 102 species of Korean birds to improve amplification success, and we attempted to identify bird species from 39 avian fecal samples collected during 4 months from Jinan, South Korea. Simultaneously, we conducted a dietary analysis using a universal DNA mini-barcode (Uni_Minibar) from same fecal samples. In silico analysis on newly designed mini-barcode represented that genetic distances were 0.5% in species and 9.1% in genera. Intraspecific variations of 149 species out of 174 species (86%) between Korea and North America were within the threshold (5.3% threshold in this study). From environmental fecal samples collected in Jinan, we identified seven avian species, which have high similarity (99-100%) with registered COI sequences in GenBank. Eight kinds of prey species, such as moth, spider, fly, and dragonfly, were identified in dietary analysis. We suppose that our strategy applying mini-barcode for environmental fecal samples, might be a useful and convenient tool for species identification and dietary analysis for birds.

• Journal of computational fluids engineering
• /
• v.6 no.1
• /
• pp.21-30
• /
• 2001

A numerical study on the similarity of the developing laminar flows between in a straight duct rotating about an axis perpendicular to that of the duct and in a stationary curved duct was carried out. In order to clarify the analogy of two flows, dimensionless parameters K/sub LR/ = Re/(equation omitted) and Rossby number, Ro, in a rotating straight duct were used as a set corresponding to Dean number K/sub LC/ = Re/(equation omitted), and curvature ratio, λ, in a stationary curved duct. For the large values of Ro and λ, it is shown that the flow field satisfies the 'asymptotic invariance property', that is, there are strong quantitative similarities between the two flows such as flow patterns, friction factors, and maximum axial velocity magnitudes for the same values of K/sub LR/ and K/sub LC/ if they are correlated with dimensionless axial distances Z/sub R/ = z/(equation omitted) for a rotating duct flow and Z/sub C/ = z/(equation omitted) for a stationary curved duct flow.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.05a
• /
• pp.376-380
• /
• 2015

This paper proposes new recognition method of road lanes misty day. The method enables autonomous-driving of cars and the safety of the drivers while driving with bad visibility in foggy roads. The proposed method, firstly, determines whether the foggy or not according to pixel number distributions and starting point of the fog period from input images. If it is foggy then the median filter's size of the Retinex algorithm is set to 1000 or more and it performs histogram equalization and normalization. The computer simulation results show that the proposed method can recognize better long distances and fine detection than earlier methods.

• ETRI Journal
• /
• v.45 no.2
• /
• pp.291-303
• /
• 2023

Selfies are a popular form of photography. However, due to physical constraints, the compositions of selfies are limited. We present algorithms for creating virtual portraits with interesting compositions from a set of selfies. The selfies are taken at the same location while the user spins around. The scene is analyzed using multiple selfies to determine the locations of the camera, subject, and background. Then, a view from a virtual camera is synthesized. We present two use cases. After rearranging the distances between the camera, subject, and background, we render a virtual view from a camera with a longer focal length. Following that, changes in perspective and lens characteristics caused by new compositions and focal lengths are simulated. Second, a virtual panoramic view with a larger field of view is rendered, with the user's image placed in a preferred location. In our experiments, virtual portraits with a wide range of focal lengths were obtained using a device equipped with a lens that has only one focal length. The rendered portraits included compositions that would be photographed with actual lenses. Our proposed algorithms can provide new use cases in which selfie compositions are not limited by a camera's focal length or distance from the camera.

• Journal of the Korean Chemical Society
• /
• v.42 no.1
• /
• pp.9-15
• /
• 1998

The geometrical parameters, vibrational frequencies, and IR intensities of dimethyldioxirane had been investigated using high level ab initio quantum mechanical methods with various basis sets. The polarization function decreases C-O and C-C bond distances significantly and the electron correlation effect increases those bond lengths slightly, while other bond lengths and bond angles are relatively stable for basis set size and correlation effect. The experimental and other theoretical vibrational frequencies and IR intensities of dimethyldioxirane will be compared and discussed with our high level theoretical predictions.

• Journal of Energy Engineering
• /
• v.12 no.1
• /
• pp.17-22
• /
• 2003

The present study was conducted to obtain the fundamental knowledge on the manufacturing and operating characteristics of a small scale CPL (Capillary Pumped Loop) heat pipe. CPL heat pipes are able to transfer heat effectively at any orientation in a gravitational field over long distances. An experimental model with an evaporator of a circular plate shape was designed and manufactured and its operating performances were tested. A Bronze powder sintered metal plate of 3 mm thick and $\Psi$ 50 mm was used as wick and ethanol was used as working fluid. An experimental apparatus was set up to ascertain the operating conditions oi CPL at different heat load and an surrounding temperature at the condenser was maintained about 13$^{\circ}C$.

• Journal of the Korea Society of Computer and Information
• /
• v.20 no.2
• /
• pp.21-28
• /
• 2015

In this paper, we propose a prototype-based classification learning by using the nearest-neighbor rule. The nearest-neighbor is applied to segment the class area of all the training data into spheres within which the data exist from the same class. Prototypes are the center of spheres and their radii are computed by the mid-point of the two distances to the farthest same class point and the nearest another class point. And we transform the prototype selection problem into a set covering problem in order to determine the smallest set of prototypes that include all the training data. The proposed prototype selection method is based on a greedy algorithm that is applicable to the training data per class. The complexity of the proposed method is not complicated and the possibility of its parallel implementation is high. The prototype-based classification learning takes up the set of prototypes and predicts the class of test data by the nearest neighbor rule. In experiments, the generalization performance of our prototype classifier is superior to those of the nearest neighbor, Bayes classifier, and another prototype classifier.

• Journal of radiological science and technology
• /
• v.21 no.1
• /
• pp.52-58
• /
• 1998

We can and must improve the diagnostic images using available knowledge and technology. At the same time we must strive to reduce the patient's integral and entrance radiation dose. Reducing the integral dose to the patient during the radiologic procedure is a primary concern of the patient, especially the pediatric patient, the radiologist and the technologist. A 100cm focal film distance generally is used for most over-table radiography. The early x-ray tubes and screen film combinations required long exposures, which often resulted in motion artifacts. But nowaday, we have the generators and x-ray tubes that can deliver the energy necessary in a very short time and the receptors that can record the information just as rapidly. And, we performed this studies to evaluate the patient exposure dose and the image quality by increasing focal film distance in diagnostic radiography. There are many factors which affected to exposure factor, but we studied to verify of FFD increase, only. Effect of increasing the focal film distance to a 140 cm distance was tested as follows; 1. The focal film distances were set at 100, 120, and 140cm. 2. A 18cm acryl(tissue equivalent) phantom was placed on the table top. 3. An Capintec 192 electrometer with PM 05 ion chamber was placed at the entrance surface of the phantom, and exposure were made at each focal film distances. 4. The procedure was repeated in the same manner as above except the ion chamber was placed beneath the phantom at the film plane. 5. Exit exposure were normalize to 8mR for each portions of the experiment. Based on the success of the empirical measurements, a detailed mathematical analysis of the dose reduction was performed using the percent depth dose data. The results of this study can be summerized as followings ; 1) Increasing FFD from 100 cm to 140 cm, we would create a situation that would have a significant effect on the overall quality of radiograph and achive the 17.42% reduction of entrance dose and the 18.95% reduction of integral dose that the patient receives. 2) Thickness of Al step wedge for equal film density increased with the long distance. 3) Increasing FFD, Magnification of image was lowered. 4) Resolution of image also increased with the FFD. As the results described above, we strongly recommend using the long FFD to provide better information for our patients and profession in abdomen radiographic studies.