Hyo-Sung Kim

Effect of proton irradiation on magnetic relaxation in amorphous material

Abstract The frequency spectra of the susceptibility in the amorphous Fe 81 B 13.5 Si 3.5 C 2 of as-quenched and proton-irradiated samples show a typical Debye-type relaxation of domain walls. The susceptibility decreases with proton dose, while the relaxation frequency increases. The results are discussed in terms of the domain size and internal stress at the induced defects after proton irradiation.

Zoom Motion Estimation Using Block-Based Fast Local Area Scaling

Block-based motion estimation (ME) has been widely used in various video coding standards due to its effectiveness in removing temporal redundancy. However, this traditional ME technique suffers the limitation that it can only compensate for a pure parallel translation between frames. Various algorithms have been proposed for estimating other motion models, such as zooming, rotating, tilting, and warping. In spite of good performance for these algorithms, they are not used in the current industrial world because of their high computational complexity and incompatibility with current block-based video coding standards that limit their practical usage. In this paper, we present a novel zoom motion estimation (ZME) and motion compensation algorithm using the local area scaling technique. To represent and encode the zoom motion, we introduce a zoom vector (ZV) that either increases or decreases a reference block size. The resized reference block is then interpolated to the size of the current block in order to perform block matching. For fast ZME, we have also designed a 3-D diamond pattern search to reduce the number of unnecessary search points for the ZV. We have integrated the proposed algorithm into H.264/AVC JM reference software. Experimental results show that an average bit-rate savings of 11.01% (up to 16.87%) can be achieved for high-definition size sequences with an average 0.20 dB gain in peak signal-to-noise ratio and a less than 10% time increment in the hierarchical B structure.

Analysis of giant magneto-impedance in terms of anisotropy field in annealed amorphous Co66Fe4NiB14Si15 ribbons

Abstract The magneto-impedance (MI) profiles of Co66Fe4NiB14Si15 amorphous ribbons changed sensitively with the annealing temperature, reflecting the change in anisotropy field, which determines the field dependence of transverse permeability. The effective anisotropy field, evaluated from these profiles, were discussed in terms of the increase of magnetic softness and microstructural change due to the annealing.

Angular dependence of magnetoresistance in bilayer NiFe/NiO

Abstract The MR ratio was measured as a function of magnetizing angle, θ in bilayer NiO (300xa0A)/NiFe( x ) x =50, 100 and 300xa0A. The profile of MR ratio, a typical behaviour of two positive peaks at θ =0°, changed to the asymmetric profile with negative MR for θ ⩾30°, and nearly symmetric with respect to zero field at θ =90°. The MR ratio increased with θ and remained constant for θ ⩾40°. The MR ratio profile and their variations with θ are in good agreement with the calculated ones using single-domain model, showing that the crystalline anisotropy contributes significantly to the MR characteristics.

Relaxation of rotational magnetization in annealed Co-based amorphous ribbons

Abstract The permeability spectra for various amplitudes of AC magnetic field h 0 were measured in an annealed Co 66 Fe 4 NiB 14 Si 15 amorphous ribbon. The rotational magnetization was involved only for low-driving amplitude of h 0 ⩽ 0.4 mOe. The DC permeability and relaxation time, obtained from the spectra of rotational relaxation, were discussed in terms of the change of restoring constant by the magnetic softening and nucleated crystalline sites during annealing.

Fast block mode decision scheme for B-picture coding in H.264/AVC

The recent H.264/AVC video coding standard provides a higher coding efficiency than previous standards. H.264/AVC achieves a bit rate saving of more than 50 % with many new technologies, but it is computationally complex. Most of fast mode decision algorithms have focused on Baseline profile of H.264/AVC which does not consider B-picture coding. In this paper, a fast block mode decision scheme for B-pictures in High profile and Main profile is proposed to reduce the computational complexity for H.264/AVC. To reduce the block mode decision complexity in B-pictures of High profile, we use the SAD value after 16×16 block motion estimation. This SAD value is used for the classification feature to divide all block modes into some proper candidate search block modes. A differential mode allocation method is also used for the list (list 0, list 1) of B-slices based on the SAD value of the 16 × 16 block mode. The proposed algorithm shows the average speed-up factors of 41.9 ∼ 58.57% for IBBPBB sequences with a negligible bit increment and a minimal loss of image quality.

Multi-scale based motion estimation for high quality video coding

Block-based motion estimation (ME) has been widely used in various video coding standards due to its effectiveness removing temporal redundancy. It plays a key role in the transmission and storage of video signals at reduced bit rates. In this paper, a novel motion estimation algorithm is proposed to enhance video quality by reflecting enlarging and reducing movements such as zoom in/out scene. The experimental results show that the proposed algorithm achieves average quality enhancement of 1.19dB (up to 2.34db) in PSNR gain with acceptable increment of ME time.

A Study on Air Interface System (AIS) Using Infrared Ray (IR) Camera

In this paper, we introduce non-touch style interface system technology without any touch style controlling mechanism, which is called as Air-interface. To develop this system, we used the full reflection principle of infrared (IR) light and then user`s hand is separated from the background with the obtained image at every frame. The segmented hand region at every frame is used as input data for an hand-motion recognition module, and the hand-motion recognition module performs a suitable control event that has been mapped into the specified hand-motion through verifying the hand-motion. In this paper, we introduce some developed and suggested methods for image processing and hand-motion recognition. The developed air-touch technology will be very useful for advertizement panel, entertainment presentation system, kiosk system and so many applications.

Fast intermode decision algorithm based on contextual mode and priority information for H.264/AVC video encoding system

The recentH.264/AVCvideo coding standard provides a higher coding efficiency than previous standards. H.264/AVCachieves a bit rate saving of more than 50 % with many new technologies, but it shows very heavy computational complexity. In this paper, a fast mode decision scheme for inter-frame coding is proposed to reduce the computational complexity for H.264/AVC video encoding system. To reduce the block mode decision complexity in inter-frame coding, we use the contextual information based on the co-located and neighboring macroblocks (MBs) to detect a proper MB that can be early stopped. Then for the current MB, a priority information of the context is suggested for adding more mode types adaptively. The proposed algorithm shows the average speedup factors of 59.11 ~ 77.41% for various sequences with a negligible bit increment and a minimal loss of image quality, in JM 11.0 reference software.

Fast Inter-Mode Decision Algorithm Based on Contextual Mode and Priority Information for H.264/AVC Video Encoding System

The recentH.264/AVCvideo coding standard provides a higher coding efficiency than previous standards. H.264/AVCachieves a bit rate saving of more than 50 % with many new technologies, but it shows very heavy computational complexity. In this paper, a fast mode decision scheme for inter-frame coding is proposed to reduce the computational complexity for H.264/AVC video encoding system. To reduce the block mode decision complexity in inter-frame coding, we use the contextual information based on the co-located and neighboring macroblocks (MBs) to detect a proper MB that can be early stopped. Then for the current MB, a priority information of the context is suggested for adding more mode types adaptively. The proposed algorithm shows the average speedup factors of 59.11 ~ 77.41% for various sequences with a negligible bit increment and a minimal loss of image quality, in JM 11.0 reference software.