• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.6
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• pp.1357-1378
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• 2013

Energy constraint of wireless sensor networks makes energy saving and prolonging the network lifetime become the most important goals of routing protocols. In this paper, we propose an Energy Efficient Chain-based Routing Protocol (EECRP) for wireless sensor networks to minimize energy consumption and transmission delay. EECRP organizes sensor nodes into a set of horizontal chains and a vertical chain. Chain heads are elected based on the residual energy of nodes and distance from the header of upper level. In each horizontal chain, sensor nodes transmit their data to their own chain head based on chain routing mechanism. EECRP also adopts a chain-based data transmission mechanism for sending data packets from the chain heads to the base station. The simulation results show that EECRP outperforms LEACH, PEGASIS and ECCP in terms of network lifetime, energy consumption, number of data messages received at the base station, transmission delay and especially energy${\times}$delay metric.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.2
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• pp.141-148
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• 1998

For developing a beam shaping antenna, the circumference and the length of the vertical and horizontal elements of the Modified Transmission Line type Antenna(MTLA) are varied. The vertical radiation pattern of MTLA which has various shape was analyzed by the moment method in order to verify the beam tilt characteristics. From the analysis, it is confirmed that the condition of the maximum beam tilt is determined by the length of the vertical elements of the antenna. The antennal with the maximum beam tilt was designed and its input impedance and the radiation pattern was calculated theoretically and measured experimentally.

• Journal of IKEEE
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• v.2 no.2 s.3
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• pp.225-232
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• 1998

Currently NTSC, PAL, and SECOM are widely used for TV broadcasting systems. In Korea, NTSC has been used to reduce transmission bandwidth and broadband flickers using the Interlaced scanning method. Image data in the Interlaced scanning method require De-interlacing compensation for PC-based multimedia applications. The existing compensation algorithms such as ZOI, FOI, and ELA provieds simple computations and effective image compensation while the PSNR is low and horizontal and vertical edges are hardly detected. In this paper, the ADI(Adaptive De-Interlacing) algorithm that can increase PSNR and detect horizontal and vertical edges is proposed and a hardware system is implemented using three ACTEL 1020B FPGA chips. The system consists of the algorithm part implemented using two FPGAs and the memory control part implemented using rest one. Also the system operation is investigated for real time processing.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.10
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• pp.1356-1363
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• 1999

In this paper, a new method for controlling the pointing device using EOG(electrooculogram) signal generated from eye movement was suggested. The basic idea of the method is to control the direction of pointer, as using the results of measuring each component of the horizontal EOG and the vertical EOG by angle of eye-gaze. As a practical example, pointing device controlling the personal computer's pointer is manufactured. The designed pointing device consists of pre-amplifier, A/D converter, serial transmission device and PC program. That is, first, the EOG is amplified by pre-amplifier. Secondly, the amplified EOG is digitized and transmitted to personal computer by PIC16C74A. Finally, the software for controlling the pointer on personal computer is programed. As the result, the measured horizontal EOG and vertical EOG by eye-gaze angle had high linearity; the correlation coefficients of the regression line were 0.998 and 0.996 respectively. And the developed pointing device is able to control the personal computer's pointer, and the average of the errors between the objective value and the observed value had 3.77% for horizontal axis and 5.85% for vertical axis. The pointing device developed in this study is able to control personal computer's pointer by subject's eye movement, that is, the user's intention. Furthermore, the algorithm of this study is applicable for many field, such as a new method remote control, a new wheelchair control and so forth.

• Journal of Electrical Engineering and Technology
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• v.5 no.2
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• pp.337-341
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• 2010

In this paper, an extremely low voltage operated micro corner cube retroreflector (CCR) was fabricated for free-space optical communication applications by using bulk silicon micromachining technologies. The CCR was comprised of an orthogonal vertical mirror and a horizontal actuated mirror. For low voltage operation, the horizontal actuated mirror was designed with two PZT cantilever actuators, torsional bars, hinges, and a mirror plate with a size of $400{\mu}m{\times}400{\mu}m$. In particular, the torsional bars and hinges were carefully simulated and designed to secure the flatness of the mirror plate by using a finite element method (FEM) simulator. The measured tilting angle was approximately $2^{\circ}$ at the applied voltage of 5 V. An orthogonal vertical mirror with an extremely smooth surface texture was fabricated using KOH wet etching and a double-SOI (silicon-on-insulator) wafer with a (110) silicon wafer. The fabricated orthogonal vertical mirror was comprised of four pairs of two mutually orthogonal flat mirrors with $400{\mu}m4 (length) $\times400{\mu}m$ (height) $\times30{\mu}m$ (thickness). The cross angles and surface roughness of the orthogonal vertical mirror were orthogonal, almost $90^{\circ}$ and 3.523 nm rms, respectively. The proposed CCR was completed by combining the orthogonal vertical and horizontal actuated mirrors. Data transmission and modulation at a frequency of 10 Hz was successfully demonstrated using the fabricated CCR at a distance of approximately 50 cm.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.3
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• pp.101-104
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• 2008

GaN films were grown on the vertical and horizontal reactors by the hydride vapour phase epitaxy (HVPE). The structural and optical characteristics of the GaN films were investigated depending on the reactor-type. GaN epilayers were characterized by double crystal X-ray diffraction (DC-XRD), transmission electron microscopy (TEM) and photoluminescence (PL). Surface defects of two kinds of the GaN films were revealed by the wet chemical etching method, using $H_3PO_4$ acid at $200^{\circ}C$ for 8 minutes. Hexagonal etch pits were analyzed by optical microscopy and SEM. Etch pit densities were calculated to be approximately $1.4{\times}10^7$ and $1.2{\times}10^6\;cm^{-2}$ for GaN layers grown on horizontal and vertical reactors, respectively. Those results show GaN grown in the vertical reactor having a better quality of optical properties and crystallinity than that in the horizontal reactor.

• Applied Microscopy
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• v.25 no.4
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• pp.115-123
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• 1995

This study was carried out to observe the functional ultrastructures of photoreceptor cells in frog(Rana catesbeiana) retina using transmission electron microscope. The photoreceptor cells are divided into two types-rod and cone cells-consist of outer and inner segment. The long outer segment of rod cell contains dense stacks of membrane and formed vertical and horizontal folds. The outer segment of cone cell is small, and vertical and horizontal folds are not exist. The electron dense cytoplasm of rod cell contains compact mitochondria, Golgi complexes, and endoplasmic reticula. The inner segment of cone cell shows low electron density and contains a large lipid droplet in the upper part of inner segment. In addition, cone cell contains many mitochondria, Golgi complexes. rough endoplasmic reticula, ribosomes and numerous glycogen particles. It is believed that these ultrastructural characteristics are closely associated with photoreceptive function of photoreceptor cells in frog retina.

• The KIPS Transactions:PartC
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• v.13C no.2 s.105
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• pp.177-184
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• 2006

A handover is a technology that enables data transmission and receipt seamlessly while a mobile station moves from the current base station to another base station. The handover is basically classified into two types; a horizontal handover which changes a radio link only without changing a network link, and a vertical handover which changes both in heterogeneous networks. In this paper, we propose a vertical handover protocol in a dual base station which supports both of W-CDMA and WiBro networks based on SDR (Software Defined Radio), verify the rightness using a state transition diagram and a Petri-net, and evaluate the performance of the proposed protocol using NS-2 simulator.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.409-412
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• 2001

This paper decides provision of brightness by average value of horizontal pixel, vertical pixel association. Give weight at association value calculation to improve diagonal line characteristics, and applied method to add average of vertical pixel and average of diagonal line pixel at interpolation. Therefore it improves PSNR, and it proposed algorithm that improve horizontal outline and vortical outline characteristics in big area of luminance contrast. It changed scanning line of serial scan based on proposed algorithm and designed variable image system for efficient data transmission through PCI interface circuit.

• Journal of the Optical Society of Korea
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• v.4 no.1
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• pp.58-61
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• 2000

Viewing zone shape and size perform a key role in creating viewing comfort for the viewer. The horizontal and vertical sizes of viewing zones, formed by a full color transmission type holographic screen with a stereoscopic image projection are investigated. The screens have been recorded as holograms of a narrow stripe shaped object with different width; to extend the vertical size of the viewing zone the holograms were exposed two times with the hologram shifting between exposures. The viewing zone parameters were measured as a function of the stripe width of the object and of the exit pupil size of projection optics for several holographic screens having the size of the 30 $\times$ 40 $\textrm{cm}^2$.