• Smart Structures and Systems
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• v.18 no.2
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• pp.335-354
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• 2016

This contribution presents an extended one-dimensional theory for piezoelectric beam-type structures with non-ideal electrodes. For these types of electrodes the equipotential area condition is not satisfied. The main motivation of our research is originated from passive vibration control: when an elastic structure is covered by several piezoelectric patches that are linked via resistances and inductances, vibrational energy is efficiently dissipated if the electric network is properly designed. Assuming infinitely small piezoelectric patches that are connected by an infinite number of electrical, in particular resistive and inductive elements, one obtains the Telegrapher's equation for the voltage across the piezoelectric transducer. Embedding this outcome into the framework of Bernoulli-Euler, the final equations are coupled to the wave equations for the longitudinal motion of a bar and to the partial differential equations for the lateral motion of the beam. We present results for the wave propagation of a longitudinal bar for several types of electrode properties. The frequency spectra are computed (phase angle, wave number, wave speed), which point out the effect of resistive and inductive electrodes on wave characteristics. Our results show that electrical damping due to the resistivity of the electrodes is different from internal (=strain velocity dependent) or external (=velocity dependent) mechanical damping. Finally, results are presented, when the structure is excited by a harmonic single force, yielding that resistive-inductive electrodes are suitable candidates for passive vibration control that might be of great interest for practical applications in the future.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.152-155
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• 2002

In this paper, a new approach is proposed for the error detection dedicated to MPEG-4 video coding by using the digital watermarking. In the process of encoding, the proposed scheme abstracts the macroblock features of headers, motion vectors, and Discrete Cosine Transform (DCT) coefficients, which are embedded in the quantized DCT coefficients as the digital watermarks. The decoder performs the accurate error detection through the watermark extraction. Simulation results demonstrate that the error detection ability of the proposed approach can be significantly enhanced, and that digital watermark embedding incurs little degradation to the picture quality.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2002.11a
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• pp.169-172
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• 2002

Embedding information into video data is a topic that recently gained increasing attention. This paper proposes a new approach for digital watermarking and secure copyright protection of video, the principal aim being to discourage illicit copying and distribution of copyrighted material. The method presented here is based on the three dimensional discrete cosine transform of video scene, in contrast with previous works on video watermarking where each video frame was marked separately, or where only intra-frame or motion compensation parameters were marked in MPEG compressed videos. The watermark sequence used is encrypted, pseudo-noise signal to the video. The performance of the presented technique is evaluated experimentally

• Journal of Broadcast Engineering
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• v.8 no.4
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• pp.501-504
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• 2003

In this out watermarking method, a key is determined by quantizing the maximum motion difference between frames. We have a problem the key value for embedding and detection are different in 1 to 3% frames of all frames. This problem can be easily solved by using a new key according to bit error rate of the extracted watermark. Since the watermark is embedded in each frame nth different keys and detected In all the frames, out method is resistant against attacks such as the frame averaging and frame drop.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.253-257
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• 2000

This paper reports on the development of the analysis program of the piston skirt system, PS-LAP. It is essential to verify the stability of the design and to improve the performance of the system. In order to do that efficiently, it is required that integrated and interactive simulation analysis program. PS-LAP is developed in the base of the object-oriented, capsulation, modulization, OLE(objected linking and embedding) and variational design theory. So it contain the expandability and flexibility of the structure. In addition to that, it is programed to make the convenient user interface by using the visualization programming. It can support the modification of the piston skirt shape, lubrication condition and so on. It is expected to reduce the money and effort for design the piston skirt system.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.40.2-40.2
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• 2018

NGC 5024 and NGC 5053 are among the most metal-poor globular clusters in the Milky Way. Both globular clusters are considered to be accreted from dwarf galaxies (like Sagittarius dwarf galaxy or Magellanic clouds), and common stellar envelope and tidal tails between globular clusters are also detected. We present a search for extra-tidal cluster member candidates around these globular clusters from APOGEE survey data. Using 20 chemical elements (e.g., Fe, C, Mg, Al) and radial velocities, t-distributed stochastic neighbour embedding (t-SNE), which identifies an optimal mapping of a high-dimensional space into fewer dimensions, was explored, and we find that globular cluster stars are well separated from the field stars in 2-dimensional map from t-SNE. We also find that some stars selected in t-SNE map are placed outside of the tidal radius of the clusters. The proper motion of stars outside tidal radius is also comparable to that of globular clusters, which suggest that these stars are tidally decoupled from the globular clusters. We manually measure chemical abundances for the clusters and extra-tidal stars, and discuss the association of extra-tidal stars with the clusters.

• Journal of Korea Multimedia Society
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• v.10 no.11
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• pp.1427-1438
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• 2007

Video watermarking technologies are classified into types of four kinds. The first type is to embed the watermark into a raw video signal and to code the watermarked video signal. Most of video watermarking technologies fall into the category of this type. The second type is to apply watermarking to the coding process, such as block DCT and quantization. The third is to directly embed the watermark into the compressed bitstream itself. Generally, it is referred as labelling rather than watermarking. Finally, the fourth is to embed the water mark into MPEG motion vector. This type has the difficulty in real-time process because of the high complexity and has the blocking effects because of DCT-based on coder. In this paper, we proposed the digital video watermarking that embed the watermark in SPIHT video code for I-frame using motion vector analysis. This method can remove the blocking effect occurred at the DCT-based on coder and obtain video data that has progressive transmission property. The proposed method is to select the region for the watermark embedding in I frame using motion vector estimated from the previous P or B frame. And then, it is to perform DWT and embed the watermark based on HVS into the wavelet coefficients in the same subband of DWT as the motion vector direction. Finally, the watermarked video bitstream is obtained by the SPIHT coder. The experimental results verified that the proposed method has the invisibility from the objective and subjective image quality and the robustness against the various SPIHT compression and MPEG re-code.

• Journal of The Korean Association For Science Education
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• v.40 no.1
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• pp.41-50
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• 2020

Looking at the understanding of scientific concepts from a linguistic perspective, it is very important for students to develop a deep and sophisticated understanding of words used in scientific concept as well as the ability to use them correctly. This study intends to provide the basis for productive knowledge education of scientific words by noting that the foundation of productive knowledge teaching on scientific words is not well established, and by exploring ways to teach the relationship among words that constitute scientific concept in a productive and effective manner. To this end, we extracted the relationship among the words that make up the scientific concept from the text of science textbook by using quantitative text analysis methods, second, qualitatively examined the meaning of the word relationship extracted as a result of each method, and third, we proposed a writing activity method to help improve the productive knowledge of scientific concept words. We analyzed the text of the "Force and motion" unit on first grade science textbook by using four methods of quantitative linguistic analysis: word cluster, co-occurrence, text network analysis, and word-embedding. As results, this study suggests four writing activities, completing sentence activity by using the result of word cluster analysis, filling the blanks activity by using the result of co-occurrence analysis, material-oriented writing activities by using the result of text network analysis, and finally we made a list of important words by using the result of word embedding.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.4 no.2
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• pp.211-223
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• 2009

Objectives : The aim of this research is to analyze the current trend of the studies about eridian muscle and to provide background for further studies. Methods : Reviewing 33 domestic oriental medical studies about meridian muscle, and comparative analysis was made. These studies were classified by method, theme and subtitle. Results : 1. According to the classification by study method, number of literary studies are 22(67%), which is more than half, number of experimental studies are 5(15%) and clinical studies are 6(18%). 2. According to the classification by study theme in literary study, percentage of 'Structure amp; Movement of Meridian Muscle' took 64%, Theory study of Meridian Muscle' took 14%, 'Application of Concept of Meridian Muscle' took 14%, 'Treatment of Meridian Muscle disorder' took 9% arranged in order. 3. In 'Theory study of Meridian Muscle', there were not only literary approaches but also Deficiency-Excessiveness(虛實) and historical approaches. Study about 'Structure & Movement of Meridian Muscle' includes analysis of muscle and Myofascial pain syndrome. On this background, it is necessary to recognize the linkage and motion analysis of Meridian Muscle. Therefore, studies were changed into interpretation about Anatomy trains, analysis of motion. The study about 'Treatment of Meridian Muscle disorder' provided the various treatment method-Acupuncture, Manual therapy, Ashi(阿是)-point therapy, CHUNA therapy etc.- in literary study. The study about the 'Application of Concept of Meridian Muscle' has been performed in relation to Embedding Therapy, Kyungkuen chuna, Ki-gong therapy. 4. Experimental Studies were all Anatomical Studies. Studies were done in trial of discovering the actual existence, but revealed problem in interpretating the meaning of Meridian Muscle. 5. Clinical Studies based on Ashi(阿是)-point therapy CHUNA Muscles Along Meridians Release Therapy etc, were performed. Experimental studies about Meridian Muscle were assessed as low grade according to Jadad Scale. There were no studies which were based on well-organized Meridian Muscle theory. Conclusions : There needs to be more discussion about concept of Meridian Muscle and proceed more reliable experimental studies with organized Meridian Muscle theory. Further objective studies about treatment of Meridian Muscle should be done.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.111.1-111.1
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• 2015

As an alternative way to get sophisticated nanostructures, atomic force microscopy (AFM) has been used to directly manipulate building primitives. In particular, assembly of metallic nanoparticles(NPs) can provide various structures for making various metamolecules. As far, conventionally made polygonal shaped metallic NPs showed non-uniform distribution in size and shape which limit its study of fundamental properties and practical applications. In here, we optimized conditions for deterministic manipulation of ultra-smooth and super-spherical gold nanoparticles (AuNPs) by AFM. [1] Lowered adhesion force by using platinum-iridium coated AFM tips enabled us to push super-spherical AuNPs in linear motion to pre-programmed position. As a result, uniform and reliable electric/magnetic behaviors of assembled metamolecules were achieved which showed a good agreement with simulation data. Furthermore, visualization of near field for super-spherical AuNPs was also addressed using photosensitive azo-dye polymers. Since the photosensitive azo-dye polymers can directly record the intensity of electric field, optical near field can be mapped without complicated instrumental setup. [2] By controlling embedding depth of AuNPs, we studied electric field of AuNPs in different configuration.