• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.46 no.4
• /
• pp.72-78
• /
• 2009

This paper proposes a low phase noise ring voltage controlled oscillator(VCO) with a standard $0.13{\mu}m$ CMOS process for PLL circuit using the VCO-gain-controlled Delay cell. The proposed Delay cell architecture with a active resistor using a MOS transistor. This method can reduced a VCO gain so that improve phase noise. And, Delay cell consist of Wide-Swing Cascode current mirror, Positive Latch and Symmetric load for low phase noise. The measurement results demonstrate that the phase noise is -119dBc/Hz at 1MHz offset from 1.9GHz. The VCO gain and power dissipation are 440MHz/V and 9mW, respectively.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.38 no.3
• /
• pp.82-91
• /
• 1996

This is a basic study for the static and dynamic analysis on the elasto-plastic and elasto-viscoplastic of an axi-symmetric shell. The objective of this study was to investigate the mechanical characteristics of a nuclear reinforced concrete containment structure, which was selected as a model, by a numerical analysis using a finite element method. The structure was modeled with discrete ring elements of 8-noded isoparametric element rotating against the symmetrical axis, and the interaction between the foundation and the structure was modeled by Winkler's model. Also, the meridional tendon was modeled with 2-node truss elements, and the hoop tendon was done with point elements in two degrees of freedom. The effect of the tendon was considered without the increasement in total degree of freedom as the stiffness matrix of modeled tendon elements was assembled on the stiffness matrix of ring elements linked with the tendon. The results obtained from the analysis of an example were summarized as follows : 1. The stresses in the hoop direction on the interior and exterior surfaces of the structure were shown in changes of similar trend, and high stresses appeared on the structure wall 2. The stresses in the meridional direction on the interior and exterior surfaces were shown in change of different trend. Especially, the stresses at the junctions between the dome and the wall and between the wall and the bottom plate of the structure were very high, compared with those at other parts of the structure. 3. The stress changes in the direction of thickness on the crown of the dome were much linearly distributed. However, as the amount of tendon increased, the stresses in the upper and lower parts of the wall established with the tendon were shown stress concentration. 4. The stress changes in the direction of thickness on the center of the structure wall was linearly distributed in the all cases, and special stress due to the use of the tendon was not shown.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2014.06a
• /
• pp.163-165
• /
• 2014

In this paper, we propose a world's first programmable video processing platform for video quality enhancement of 8K ($7680{\times}4320$) UHD (Ultra High Definition) TV at 60 frames per second. To support huge computation and memory bandwidth of video quality enhancement for 8K resolution, the proposed platform has unique features like symmetric multi-cluster architecture for data partitioning, ring data-path between clusters to support data pipelining, on-the-fly processing architecture to reduce DDR bandwidth, flexible hardware to accelerating common kernel in video enhancement algorithms. In addition to those features, general programmability of SRP (Samsung reconfigurable processor) as main core of the proposed platform makes it possible to upgrade continuously video enhancement algorithm even after the platform is fixed. This ability is very important because algorithms for 8K DTV is under development. The proposed sub-system has been embedded into SoC (System on Chip) and new 8K UHD TV using the programmable SoC is expected at CES2015 for the first time in the world.

• Journal of Broadcast Engineering
• /
• v.20 no.5
• /
• pp.774-777
• /
• 2015

This paper introduces the world's first programmable video-processing platform for the enhancement of the video quality of the 8K(7680x4320) UHD(Ultra High Definition) TV operating up to 60 frames per second. In order to support required computing capacity and memory bandwidth, the proposed platform implemented several key features such as symmetric multi-cluster architecture for parallel data processing, a ring-data path between the clusters for data pipelining and hardware accelerators for computing filter operations. The proposed platform based on RP(Reconfigurable Processor) processes video quality enhancement algorithms and handles effectively new UHD broadcasting standards and display panels.

• Proceedings of the KSME Conference
• /
• 2002.08a
• /
• pp.151-154
• /
• 2002

The twin impulse wave leads to very complicated flow fields, such as Mach stem, spherical waves, and vortex ring. The twin impulse wave discharged from the exits of the two tubes placed in parallel is investigated to understand detailed flow physics associated with the twin impulse wave, compared with those in a single impulse wave. In the current study, the merging phenomena and propagation characteristics of the impulse waves are investigated using a shock tube experiment and by numerical computations. The Harten-Yee's total variation diminishing (TVD) scheme is used to solve the unsteady, two-dimensional, compressible, Euler equations. The Mach number $M_{s}$, of incident shock wave is changed below 1.5 and the distance between two-parallel tubes, L/d, is changed from 1.2 to 4.0. In the shock tube experiment, the twin impulse waves are visualized by a Schlieren optical system for the purpose of validation of computational work. The results obtained show that on the symmetric axis between two parallel tubes, the peak pressure produced by the twin-impulse waves and its location strongly depend upon the distance between two parallel tubes, L/d and the incident shock Mach number, $M_{s}$. The predicted Schlieren images represent the measured twin-impulse wave with a good accuracy.

• Bulletin of the Korean Mathematical Society
• /
• v.29 no.2
• /
• pp.265-275
• /
• 1992

The characteristic free representation theory of the general linear group has found a wide range of applications, ranging from the theory of free resolutions to the symmetric function theory. Representation theory is used to facilitate the calculation of explicit free resolutions of large classes of ideals (and modules). Recently, K. Akin and D. A. Buchsbaum [2] realized the Jacobi-Trudi identity for a Schur function as a resolution of GL$_{n}$-modules. Over a field of characteristic zero, it was observed by A. Lascoux [6]. T.Jozefiak and J.Weyman [5] used the Koszul complex to realize a formula of D.E. Littlewood as a resolution of schur modules. This leads us to further study resolutions of Schur modules of a particular form. In this article we will describe some new classes of finite free resolutions associated to the Pieri type skew Young diagrams. As a special case of these finite free resolutions we obtain the generalized Koszul complex constructed in [1]. In section 2 we review some of the basic difinitions and properties of Schur modules that we shall use. In section 3 we describe certain exact complexes associated to the Pieri type skew partitions. Throughout this article, unless otherwise specified, R is a commutative ring with an identity element and a mudule F is a finitely generated free R-module.e.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.48 no.9
• /
• pp.476-483
• /
• 1999

In this paper, electromagnetic forces acting on the rotor surface of a BLDC motor for hard disk drive are calculated by the finite element field analysis. The frequency characteristics of torque ripple, local force and unbalanced magnetic force as a source of mechanical vibration area analyzed. Ring-type permanent magnets for the brushless DC motor are apt to have different magnetization levels at each pole because of the unbalanced air gap between the magnet surface and the magnetizer fixture during the multi-poles magnetizing process. This paper discusses the effect of the unsymmetric magnetization distribution in the permanent magnet on the brushless DC motor performances. As a result, the unbalanced magnetic force acting on the rotor surface and the torque ripple are examined for the motor with an unsymmetric magnetization distribution, and compared with those of an ideally symmetric motor.

• Bulletin of the Korean Mathematical Society
• /
• v.22 no.2
• /
• pp.121-126
• /
• 1985

D.K. Harrison [5] has shown that if R and S are fields of characteristic different from 2, then two Witt rings W(R) and W(S) are isomorphic if and only if W(R)/I(R)$^{3}$ and W(S)/I(S)$^{3}$ are isomorphic where I(R) and I(S) denote the fundamental ideals of W(R) and W(S) respectively. In [1], J.K. Arason and A. Pfister proved a corresponding result when the characteristics of R and S are 2, and, in [9], K.I. Mandelberg proved the result when R and S are commutative semi-local rings having 2 a unit. In this paper, we prove the result when R and S are 2-fold full rings. Throughout this paper, unless otherwise specified, we assume that R is a commutative ring having 2 a unit. A quadratic space (V, B, .phi.) over R is a finitely generated projective R-module V with a symmetric bilinear mapping B: V*V.rarw.R which is nondegenerate (i.e., the natural mapping V.rarw.Ho $m_{R}$ (V, R) induced by B is an isomorphism), and with a quadratic mapping .phi.:V.rarw.R such that B(x,y)=(.phi.(x+y)-.phi.(x)-.phi.(y))/2 and .phi.(rx)= $r^{2}$.phi.(x) for all x, y in V and r in R. We denote the group of multiplicative units of R by U(R). If (V, B, .phi.) is a free rank n quadratic space over R with an orthogonal basis { $x_{1}$, .., $x_{n}$}, we will write < $a_{1}$,.., $a_{n}$> for (V, B, .phi.) where the $a_{i}$=.phi.( $x_{i}$) are in U(R), and denote the space by the table [ $a_{ij}$ ] where $a_{ij}$ =B( $x_{i}$, $x_{j}$). In the case n=2 and B( $x_{1}$, $x_{2}$)=1/2, we reserve the notation [ $a_{11}$, $a_{22}$] for the space.the space.e.e.e.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.3
• /
• pp.99-114
• /
• 2012

Proxy Mobile IPv6 (PMIPv6) has received considerable attention between telecommunications and the Internet communities and does not require active participation of the Mobile Node (MN) by way of network-based mobility management. The PMIPv6 domain is studying establishment in progress to support extensively a number of MN by using a low handover latency. In this research, we are propose a novel 3S scheme for building Scalable and Secure and Seamless PMIPv6 domains. In the proposed scheme, all of Mobility Access Gateway (MAG) are acting as the Local Mobility Anchor (LMA) and composing a virtual ring with another MAG. General hashing is used in the efficient distribution-mapping between each MN and the MN's LMA of all MAGs. And, MAG and MN are authenticated using the symmetric key. Through mathematical analysis, we verifies the safety, scalability, and seamless service for 3S. Also, we're propose a handover procedure of 3S and show better than the existing schemes in terms of handover latency.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.22 no.4
• /
• pp.450-467
• /
• 1998

The characteristics of the unstable impinging circular jet is investigated based on the frequency characteristics and the sound field of the impinging-tones. Two symmetric modes S1 and S2, associated with low frequency and high frequency respectively, and one helical mode H have been observed. At low speed the S2 mode is dominant and switched by the S1 mode as the speed increases. When the jet speed is high the S1 mode is very active over the impinging distance from half the nozzle diameter to its ten times, while the S2 mode occurs at shorter distance corresponding to stage 2 and 3. The helical mode H seems unstable, likely to be influenced much by the experimental environment, and occurs at relatively high speed with almost the same frequency characteristics as the S2 mode. By estimating the convection speed of the unstable jet, it is found that the ratio of the convection speed to the jet speed decreases with both Strouhal number and Reynolds number and the speed of S2 mode is faster than the Si mode. When the present experimental results are compared with the previous investigations performed for the hole tone and the impinging tone with a small plate, the S1 mode is found to be associated with the ring vortex of large diameter with low speed, but the S2 mode with the vortex of small diameter with high speed. In addition, the frequency is found to be influenced by the nozzle configuration but the characteristics is almost the same. From the impinging distance and frequency range, it can be deduced that S1 mode is related with the jet column mode and S2 mode with the shear mode.