• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.4
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• pp.679-687
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• 2017

In this paper, a microstrip-fed triple-band monopole antenna with DGS (Defected Ground Structure) for WLAN/WiMAX applications was proposed. The proposed antenna is based on a microstrip-fed structure, and composed of two strip lines and DGS structure and then designed in order to get triple band characteristics. We carried out simulation about parameters. Adjusted the position and length of the two strips and three slits, we get the optimized parameters. The proposed antenna is fabricated on an FR-4 substrate of which the dielectric constant is 4.4, and its overall size is $34mm(W_1){\times}34mm(L_1){\times}1.6mm(t)$, and its proposed antenna size is $17.0mm(W_6){\times}30.75mm(L_3+L_4+L_9)$. From the fabricated and measured results, return loss of the proposed antenna satisfied return loss -10dB bandwidth 360 MHz (2.335~2.695 GHz), 645 MHz (3.37~4.015 GHz) and 1,770 MHz (5.14~6.91 GHz). And measured results of gain and radiation patterns characteristics displayed for operating bands.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.137-145
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• 2004

Limestone zone in korea have been distributed to diagonal line so that it is wide from the Gangwondo to the Jeonlanamdo. The limestone cavity and fractured zone were formed by chemical weathering. Limestone cavity and fractured zone was reinforced with cemented milk(w/c=60%)by high pressure jet grouting by tripple -pipe to establish bridge foundation on the ground condition like limestone cavity. To analyze property of limestone and solid of cement milk(w/c=65%), mixed solid of cement, core NX size in the limestone cavity and fractured zone and compressive strength. Seismic tomograpy exploration was pcrforn1cd to analyze deformation modulus of limestone. The analysis suggests that deformation modulus of limestone has effect on uniaxial compressive strength, seismic velocity, seismic elasticity modulus. Average static elasticity modulus of limestone is $5.08{\times}10^5kgf/cm^2$, cement and coal mixed solid is $0.25{\times}10^5kgf/cm^2$, $0.095{\times}10^5kgf/cm^2$. Average seismic velocity of limestone is 5.240m/sec, cement and coal mixed solid is 2,211.3m/sec, 1,447.5m/sec. Average uniaxial compressive strength of limestone was $1,221.3kgf/cm^2$ and limestone specimen mixed with cement milk and solid of cement milk mixed with coal were $125.22kgf/cm^2$, $35kgf/cm^2$ each other. Average friction angle of limestone was $49.14^{\circ}$ and limestone specimen mixed with cement milk and solid of cement milk mixed with coal were $38.39^{\circ}, 25.83^{\circ}$ each other. Average cohesion of limestone was $137.7kgf/cm^2$ and limestone specimen mixed with cement milk and solid of cement milk mixed with coal were $23.5kgf/cm^2$, $15.5kgf/cm^2$ each other. Average deformation modulus of limestone was $2.84{\times}10^5kgf/cm^2$ and limestone specimen mixed with cement milk and solid of cement milk mixed with coal were $0.4{\times}10^5kgf/cm^2, 0.12{\times}10^5kgf/cm^2$ each other. It was analyzed that the elasticity and uniaxial compressive strength, seismic velocity of solid of cement milk mixed limestone pieces and coal had an highly interrelation regardless of existence of limestones pieces and coal but it had shown that limestones had an lower interrelation. In case of field seismic velocity and deformation of limestone, SIC solid of cement milk mixed with coal and limestone pieces had an highly interrelation.

• Korean Chemical Engineering Research
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• v.52 no.3
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• pp.314-320
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• 2014

Regarding the design of the gas sweetening absorber, the gas distribution analysis for the increase of the sour gas removal and reduction of the tower height is very important research topics. Recently, regarding the $CO_2$ capture technology which is a promising option for the reduction of the greenhouse gas (GHG), the need for the gas distribution improvement is increased as the gas treating capacity increases. In this paper, we have investigated the sour gas distribution in the absorber using CFD (Computational Fluid Dynamics) based on 10 MW post-combustion $CO_2$ capture plant installed in Boryeong power station, Korea Midland Power company. For this purpose, we suggested the three possible technology options (splash plate, spiral gas line and U-tube) for the gas distribution enhancement and compared the effect of the each cases. The result showed that the U-tube installed in the absorber increase the gas distribution about 30% compared to the base case, while the delta P increasement was about 10%. From these results, it was found that the U-tube installation is an effective technology option for the gas distribution enhancement in the gas sweetening absorber.

• 전기의세계
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• v.2
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• pp.6-14
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• 1949

Telemetering may be described as the art of metering at a considerable distance those quantities which are ordinarily encountered in industry, and in the generation of electric power. It is in the production of electric power that telemetering is particularly important, for it permits the system operator, or load dispatcher, to have before him at all times a continuous graphic record of the power output of each individual generating station together with an automatically made continuous graphic record of the total system output. There desired individual graphic records may be obtained showing power flow in or out, on important tie lines, etc. Such arrangements have the very great advantage that loads may be assigned to each generating station so that the best over-all system economy may be obtained and the system operator at all times may see with his own eyes that loads scheduled are actually held at the various stations. Moreover, with such equipment, in the event of system or station trouble the load dispatcher can see exactly what station, or stations, are affected and to what extent, without having to get in touch with anyone by telephone. Decisions can, therefore, be quickly reached for rescheduling the load. One of the most accurate and reliable telemetering systems is based on the use of potentiometric circuits, the fundamentals of which are discussed below. A member of such telemetering systems have been installed for the Boston Edicon Co., Boston, Massachusetts, the Consolidated Edison Co. of New York City. The Public Service Gas & Electric Co. of Newark, new Jersey. The Philadelphia Electric Co. for Philadelphia, Pennsylvania, and the Pennsylvania Railroad Co. for their electrified zone between New York and Washington a distance of over 200 miles. The scale of the totalizing recorder for the New York area is 3,000,00 KW. That of the totalizing recorder for the Philadelphia area is 2,000,000 KW. The initial installation using this type of equipment described was placed in service for the Philadelphia Electric Co. in 1923. All of the original recording instruments are still in service, later instruments have been added to take care of additions to the power system and naturally these later recorders have incorporated in those refinements in design made since the earlier ones were manufactured. Many other installations of similar equipment have been made in the United States in various locations such as at St. Louis, on the West Coast, at Baltimore and in Washington, D.C. While the use of these basic potentiometric circuits involves the use of continuous metallic circuits of good insulation resistance and free of grounds, nevertheless, intermediate transmission links, involving and impulse method suitable for use on telephone Morse carrier channels is available. This same method may be employed on power line carrier systems and is also suitable for use on beam type microwave transmission. Many impulse type units are also used as a link in these potantiometric methods. For the sake of brevity a description is given only of these basic potentiometric circuits. If there is sufficient interest in Korea, a further paper can be given covering those impulse circuits also.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.5
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• pp.87-93
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• 2010

This paper presents a high resolution, wide input range 2-step time-to-digital converter used in digital PLL. TDC is used to compare the DPLL output frequency with reference frequency and should be implemented with high resolution to improve the phase noise of DPLL. The conventional TDC consists of delay line realized inverters, whose resolution is determined by delay time of inverter and transistor size, resulting in limited resolution. In this paper, 2-step TDC with phase-interpolation and Time Amplifier is proposed to meet the high resolution and wide input range by implement the delay time less than an inverter delay. The gain of Time Amplifier is improved by using the delay time difference between two inverters. It is implemented in $0.13{\mu}m$ CMOS process and the die area is $800{\mu}m{\times}850{\mu}m$ Current consumption is 12 mA at the supply voltage of 1.2 V. The resolution and input range of the proposed TDC are 0.357 ps and 200 ps, respectively.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.4
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• pp.39-50
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• 2011

In this paper, we presents a CDR circuit for $2^{nd}$-generation AiPi+, one of the Intra-panel Interface. The speed of the proposed clock and data recovery is increased to 1.25 Gbps compared with that of AiPi+. The DLL-based CDR architecture is used to generate the multi-phase clocks. We propose the simple scheme for frequency detector (FD) to mitigate the harmonic-locking and reduce the complexity. In addition, the duty cycle corrector that limits the maximum pulse width is used to avoid the problem of missing clock edges due to the mismatch between rising and falling time of VCDL's delay cells. The proposed CDR is implemented in 0.18 um technology with the supply voltage of 1.8 V. The active die area is $660\;{\mu}m\;{\times}\;250\;{\mu}m$, and supply voltage is 1.8 V. Peak-to-Peak jitter is less than 15 ps and the power consumption of the CDR except input buffer, equalizer, and de-serializer is 5.94 mW.

• Journal of Environmental Science International
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• v.24 no.11
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• pp.1405-1415
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• 2015

This study is conducted to determine the damage, distinguish the types and identify the restoration by that type for 13 Korea national parks out of 21. There are 21 Korea national parks are in Korea covering 6.67% of the country or $6,656km^2$ ($3,902km^2$ on land and $2,754km^2$ in the sea) currently since the area around Jirisan ($440km^2$) was designated as the first Korea national parks in 1967. With the cancellation of entrance admission on Korea national parks since 2007, annual visitors to the Korea national parks have grown from 37 millions in 2008 to 46 millions by 2013 and continue to grow due to numerous leisure activities, alpine activities and social changes. As such, Korea national parks are natural resource with high value to be conserved and are attracting significant attention as recreational spaces for people at the same time. On the other hand, there have been issues of soil erosions or disturbed vegetation due to increased number of visitor to the national parks. Korea national parks area damage to its type and damage characteristics to analyse the 13 Korea national parks out of 21 on July 2012 March, Korea national parks over the subjects of the National Park from damaged area status Survey analysis by the Korea National Park Service. As a result, 203 million units in the 16 Korea national parks damaged land of the reform package during ecological trail (including non-regular hiking trails) 153 (77.66%), damaged valleys 20(9.14%) independent damaged area, 13 disconnected ecological axis(7.61%), closed trail(2.03%) (3.55%), and line type damage(like a non-regular hiking trails) appears to be a high ratio. Korea national parks damaged land of the results identified, by contrast ratio and the annual number of visitors Bukhansan national park(49.26%), Gyeongju national park(23.65%) damaged land rates, such as Seorasan national park(4.93%), Songnisan national park (4.43 %), Gyeryongsan national park(3.45%), and the annual number of visitors be similar result. The National Park Service has been reporting on damages and restorations but damages and their types have not been established yet. Damages have been generally studied and categorized on hiking trails due caused by heavy traffic on them but the reports were limited on hiking trails only. Since damage to the Korea national parks are not limited on the hiking trails, it is necessary to determine damages in various aspects. Thus, in this study, damage types, spatial characteristics, causes and restorations are analyzed based on the survey results of damages to national parks in order to provide a basis for the efficient management and operation of the Korea national parks.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.26-36
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• 2006

In this paper, we propose a cost-effective color filter may (CFA) demosaicing method for digital still cameras in which a single CCD or CMOS image sensor is used. Since a CFA is adopted, we must interpolate missing color values in the red, green and blue channels at each pixel location. While most state-of-the-art algorithms invest a great deal of computational effort in the enhancement of the reconstructed image to overcome the color artifacts, we focus on eliminating the color artifacts with low computational complexity. Using spatial correlation of the adjacent pixels, the edge-directional information of the neighbor pixels is used for determining the edge direction of the current pixel. We apply our method to the state-of-the-art algorithms which use edge-directed methods to interpolate the missing color channels. The experiment results show that the proposed method enhances the demosaiced image qualify from $0.09{\sim}0.47dB$ in PSNR depending on the basis algorithm by removing most of the color artifacts. The proposed method was implemented and verified successfully using verilog HDL and FPGA. It was synthesized to gate-level circuits using 0.25um CMOS standard cell library. The total logic gate count is 12K, and five line memories are used.

• Spatial Information Research
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• v.12 no.1
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• pp.13-27
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• 2004

The current industrial development and the increase of population in Daecheong Reservoir basin have produced a rapid increase of wastewater discharge. This has resulted in problem of water quality control and management. Although many efforts have been carried out, reservoir water quality has not significantly improved. In this sense, the development of water quality management system is required to improve reservoir water quality. The goal of this study is to design a GIS-based water quality management system for the scientific water quality control and management in the Daecheong Reservoir. For general water quality analysis, WASP5 model was applied to the Daecheong Reservoir. A sensitivity analysis was made to determine significant parameters and an optimization was made to estimate optimal values. The calibration and verification were performed by using observed water quality data for Daecheong Reservoir. A water quality management system for Daecheong Reservoir was made by connecting the WASP5 model to ArcView. It allows a Windows-based Graphic User Interface(GUI) to implement all operation with regard to water quality analysis. The proposed water quality management system has capability for the on-line data process including water quality simulation, and has a post processor far the reasonable visualization for various output. The modeling system in this study will be an efficient NGIS(National Geographic Information System) far planning of reservoir water quality management.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.9
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• pp.886-894
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• 2014

A wideband bow-tie antenna fed by wideband microstrip-coplanar stripline(CPS) balun and band notch structures that can be applied to bow-tie antenna are proposed in this paper. In order to increase bandwidth, bow-tie radiators are reshaped so that the surface current flows continuously, and wideband impedance matching is achieved by adjusting strip width and spacing of CPS feeding line. The VSWR is measured as 2:1 over the wide frequency range of 2.3~12 GHz. The fabricated antenna size is $60mm{\times}60mm$. In order to achieve the band-notch function at WLAN(5.8 GHz), ${\lambda}/4$ folded-slits located ${\lambda}/4$ away from feeding point are utilized. To minimize the slit size, folded-slit type is adopted. The measured VSWR is 7:1 and gain attenuation is 14 dB at 5.8 GHz.