• Smart Structures and Systems
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• v.2 no.1
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• pp.1-24
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• 2006

The optimal design of multiple tuned mass dampers (multiple TMD's) to suppress multi-mode structural response of beams and floor structures was investigated. A new method using a numerical optimizer, which can effectively handle a large number of design variables, was employed to search for both optimal placement and tuning of TMD's for these structures under wide-band loading. The first design problem considered was vibration control of a simple beam using 10 TMD's. The results confirmed that for structures with widelyspaced natural frequencies, multiple TMD's can be adequately designed by treating each structural vibration mode as an equivalent SDOF system. Next, the control of a beam structure with two closely-spaced natural frequencies was investigated. The results showed that the most effective multiple TMD's have their natural frequencies distributed over a range covering the two controlled structural frequencies and have low damping ratios. Moreover, a single TMD can also be made effective in controlling two modes with closely spaced frequencies by a newly identified control mechanism, but the effectiveness can be greatly impaired when the loading position changes. Finally, a realistic problem of a large floor structure with 5 closely spaced frequencies was presented. The acceleration responses at 5 positions on the floor excited by 3 wide-band forces were simultaneously suppressed using 10 TMD's. The obtained multiple TMD's were shown to be very effective and robust.

• Publications of The Korean Astronomical Society
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• v.21 no.2
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• pp.21-26
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• 2006

A Korean team (Korea Astronomy and Space Science Institute, Korea Basic Science Institute, and Kyung Hee University) takes part in an international cooperation project called CIBER (Cosmic Infrared Background ExpeRiment), which has begun with Jet Propulsion Laboratory (JPL) in USA and Institute of Space and Astronautical Science (ISAS) in Japan. CIBER is a rocket-borne instrument, of which the scientific goal is to measure the cosmic near-infrared extra-galactic background to search for signatures of primordial galaxy formation. CIBER consists of a wide-field two-color camera, a low-resolution absolute spectrometer, and a high-resolution narrow-band imaging spectrometer. The Korean team is in charge of the ground support electronics and manufacturing of optical parts of the narrow-band spectrometer, which will provide excellent opportunities for science and technology to Korean infrared groups.

• Journal of the Korea Society of Computer and Information
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• v.4 no.3
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• pp.73-77
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• 1999

In this paper. wavelet transform coding for image conference is studied. Original video frames are transformed into hierarchical pyramidal images with multiresolution using the band property of wavelet transform coefficients. Moving information between neighboring frames is obtained from the low-resolution band. Also, to control the video coding procedure. a new picture set filter is proposed. This filter controls the compression ratio of each frame depending on the correlation to the reference frame by selectively eliminating less important high-resolution areas. Consequently. video quality can be preserved and bit rate can be controlled adaptively In the simulation, to test the performance of the proposed coding method, comparisons with the full search block matching algorithm and the differential image coding algorithm are made. Consequently. the proposed method shows a reasonably good performance over existing ones.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.61-64
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• 2003

A band function model paired comparison method (BMPC method) is a kind of a paired comparison methods. Considering the human ambiguities, the BMPC method expressing the human judgment characteristics as a monotonous increase function with some width. Since function types are not specified in a BMPC method, the solution is obtained from inequalities, and the solution is given as a domain. To solve the simultaneous inequalities, the sequential renew method is used in the previous BMPC method. However, the sequential renew method requires much computational effort and memories. Generally, in BMPC method, it is able to solve only a paired comparison table which has less 12-13 samples. For that purpose, a new fast solution algorithm is required. In this paper, we proposed a new “search vector method” which renews the solution domain without creating new edge vectors. By using the method, it is able to decrease the necessary memory spaces and time to solve. The proposed method makes it able to solve more than 15 samples paired comparison inspections which are impossible to solve by previous method.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.2
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• pp.19-26
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• 1995

The design of broad-band, thin layer electromagnetic wave absorbers usually employs magnetic materials. The common absorber consists of a magnetic material layer bonded to a metal plate at the back. For such structure, a theoretical expression involving six parameters defines the allowable material shape and values of electromagnetic parameters that will produce zero reflection or more practically more than 99% absorption (20dB attenuation). The Secant Method was employed to compute the matching boundary values corresponding to 20dB attenuation. In addition, a search algorithm coupled with the Secant Method was developed to obtain allowable range of material parameters for the design of wave absorbers. These numerical methodes applicable to any six parameters effectively yielded accurate solutions in the least iterations.

• Journal of Navigation and Port Research
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• v.30 no.5 s.111
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• pp.357-362
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• 2006

This paper describes two kinds of personal hand-held electronic devices to enhance marine leisure safety. The one is Radar response-type safety device triggering by the pulse signal from a commercial 9GHz-band Radar to provide quick search and rescue with combined civilian-government-military fleets. The other one is M-RFID (Marine Radio Frequency IDentification) based safety electronic device using 900MHz Tx/Rx with spread spectrum frequency hopping and GPS. Through the field tests at sea using Korea Coast Guard's warship the operating performances are verified. Further plan for practical use of each device was also discussed.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.46.3-46.3
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• 2019

We present our observational and theoretical investigation of Raman-scattered features in symbiotic stars (SySts). SySts are long interacting binaries, consisting of a hot compact star and an evolved giant, whose interaction via accretion process is at the origin of a tangled network of gas and dust nebulae. These systems are ideal objects to study a variety of important astrophysical problems, and have also been proposed as possible progenitors of type Ia supernova. In this talk, we emphasize that Raman-scattered features are exclusive spectroscopic tools to probe the stellar wind accretion processes in SySts. We studied mass transfer and mass loss processes in SySts using high resolution spectra obtained with 1.8m telescope at Mt. Bohyun and the 6.5m Magellan-Clay telescope combining with the theoretical modeling of radiative transfer of Raman-scattered features. We also note that there are a much smaller number of SySts known in our Galaxy, implying the necessity of systematic search programs. In view of the fact that Raman O VI features at $6830{\AA}$ are found in only bona fide SySts, we will carry out a photometric search of objects with Raman O VI features using a narrow band filter centered at $6830{\AA}$ in Local group galaxies.

• Journal of KIISE:Software and Applications
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• v.30 no.5_6
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• pp.444-453
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• 2003

Recently, a great interest of bio-technology(BT) is concentrated and the image analysis technique for electrophoresis gels is highly requested to analyze genetic information or to look for some new bio-activation materials. For this purpose, the location and quantity of each band in a lane should be measured. In most of existing techniques, the approach of peak searching in a profile of a lane is used. But this peak is improper as the representative of a band, because its location does not correspond to that of the brightest pixel or the center of gravity. Also, it is improper to measure band quantity in most of these approaches because various enhancement processes are commonly applied to original images to extract peaks easily. In this paper, we adopt an approach to measure accumulated brightness as a band quantity in each band region, which Is extracted by not using any process of changing relative brightness, and the gravity center of the region is calculated as a band location. Actually, we first extract lanes with an entropy-based threshold calculated on a gel-image histogram. And then, three other methods are proposed and applied to extract bands. In the MER method, peaks and valleys are searched on a vertical search line by which each lane is bisected. And the minimum enclosing rectangle of each band is set between successive two valleys. On the other hand, in the RG-1 method, each band is extracted by using region growing with a peak as a seed, separating overlapped neighbor bands. In the RG-2 method, peaks and valleys are searched on two vertical lines by which each lane is trisected, and the left and right peaks nay be paired up if they seem to belong to the same band, and then each band region is grown up with a peak or both peaks if exist. To compare above three methods, we have measured the location and amount of bands. As a result, the average errors in band location of MER, RG-1, and RG-2 were 6%, 3%, and 1%, respectively, when the lane length is normalized to a unit value. And the average errors in band amount were 8%, 5%, and 2%, respectively, when the sum of band amount is normalized to a unit value. In conclusion, RG-2 was shown to be more reliable in the accuracy of measuring the location and amount of bands.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.9
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• pp.1234-1239
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• 2006

Murrah and NiliRavi are the important North Indian buffalo breeds occupying the prominent position of being the highest milk producers. These breeds are more or less similar at morphological as well as physiological levels. The technique of RAPD-PCR was applied in the present study to identify a battery of suitable random primers to detect genetic polymorphism, elucidation of the genetic structure and rapid assessment of the differences in the genetic composition of these two breeds. A total of 50 random primers were screened in 24 animals each of Murrah and NiliRavi buffaloes to generate RAPD patterns. Of these, 26 (52%) primers amplified the buffalo genome generating 263 reproducible bands. The number of polymorphic bands for the 26 chosen RAPD primers varied from 3 (OPG 06 and B4) to 26 (OPJ 04) with an average of 10.1 bands per primer and size range of 0.2 to 3.2 kb. DNA was also pooled and analyzed to search for population specific markers. Two breed specific RAPD alleles were observed in each of Murrah (OPA02 and OPG16) and NiliRavi (OPG09) DNA pools. RAPD profiles revealed that 11 (4.2%) bands were common to all the 48 individuals of Murrah and NiliRavi buffaloes. Pair-wise band sharing calculated among the individual animals indicated considerable homogeneity of individuals within the breeds. Within breed, band sharing values were relatively greater than those of interbreed values. The low genetic distance (Nei's) value (0.109) estimated in this study is in accordance with the origin and geographical distribution of these breeds. The RAPD analysis indicated high level of genetic similarity between these two important North Indian buffalo breeds.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.73-75
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• 2017

Debris disks are important observational clues to understanding on-going planetary system formation. They are usually identified by significant mid-infrared excess on top of the photospheric emission of a central star on the basis of prediction from J-, H-, and Ks-band fluxes and the stellar model spectra. For bright stars, 2MASS near-infrared fluxes suffer large uncertainties due to the near-infrared camera saturation. Therefore we have performed follow-up observations with the IRSF 1.4 m near-infrared telescope located in South Africa to obtain accurate J-, H-, and Ks-band fluxes of the central stars. Among 754 main-sequence stars which are detected in the AKARI $18{\mu}m$ band, we have performed photometry for 325 stars with IRSF. As a result, we have successfully improved the flux accuracy of the central stars from 9.2 % to 0.5 % on average. Using this dataset, we have detected $18{\mu}m$ excess emission from 57 stars in our samples with a $3{\sigma}$ level. We find that some of them have high ratios of the excess to the photospheric emission even around very old stars, which cannot be explained by the current planet-formation theories.