• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.10 s.352
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• pp.80-89
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• 2006

The rapid development of process technology and the introduction of new materials not only make it difficult for process control but also as a result increase process variations. These process variations are barriers to successful implementation of design circuits because there are disparities between data on layout and that on wafer. This paper proposes a new design environment to determine the interconnect worstcase with accuracy and speed so that the interconnect effects due to process-induced variations can be applied to designs of $0.13{\mu}m$ and below. Common Geometry and Maximum Probability methods have been developed and integrated into the new worstcase optimization algorithm. The delay time of the 31-stage Ring Oscillator, manufactured in UMC $0.13{\mu}m$ Logic, was measured, and the results proved the accuracy of the algorithm. When the algorithm was used to optimize worstcase determination, the relative error was less than 1.00%, two times more accurate than the conventional methods. Furthermore, the new worstcase design environment improved optimization speed by 32.01% compared to that of conventional worstcase optimizers. Moreover, the new worstcitse design environment accurately predicted the worstcase of non-normal distribution which conventional methods cannot do well.

• The Journal of the Convergence on Culture Technology
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• v.3 no.3
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• pp.7-19
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• 2017

Korean standard poetry with a fixed form are Rated Sijo. These Rated Sijos can be found in the 24 number of Gosijos. Then, why should Korean standard poetry be Rated Sijo? This is because only the Rated Sijo has a fixed form frame. Rated Sijo naturally tailored by a rigid framework is the best representation of Koreans' unique breath and temperament. Also, Rated Sijo is superior to general sijo or poem in terms of literary therapeutic utility for human body. If Haiku omits the end of narrative with the rated number of sounds and invites different imaginations to each reader, the Rated Sijo presents a certain frame to the direction of the human's rated signal by constructing the essence of the narrative with the rated number of sounds. Thus, the Rated Sijo suggests the way of human harmony and communication by inducing different imagination of readers cooperating in a certain direction. So, the famous poem of Korea, Rated Sijo, presents our future as a framework of literature that can contribute to the improvement of human communication and quality of life. Therefore, research to preserve and develop the value of the Rated Sijo should now be initiated and continued.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.29-36
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• 2005

The crustal structure of Korean Peninsula is investigated by analyzing phase velocity dispersion data of Rayleigh wave. Earthquakes recorded by three component seismographs during 1999 - 2004 in South Korea are used in this study. The fundamental mode signals of Rayleigh waves are obtained from vertical components of seismograms by multiple filter technique method and phase match filter method. Velocity dispersion curves of surface waves for 14 propagation paths on the great circle are computed from the fundamental mode signals on the great circle path by two-station method. Treating the shear velocity of each layer as an independent parameter, phase velocities of Rayleigh wave are inverted. The result models are regarded as average structure for surface wave propagation paths respectively. All the results can be explained by an earth model of the Korean Peninsula comprising crust of shear-wave velocity increasing from 2.8 to 3.25 km/sec from top to 33 km depth and uppermost mantle of shear-wave velocity between 4.55 and 4.67 km/sec.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.3
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• pp.246-252
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• 2016

Since thermal power plant (TPP) equipment is operated under very high pressure and temperature, failures of the equipment give rise to severe losses of life and property. To prevent the losses, fault detection method is, therefore, absolutely necessary to identify abnormal operating conditions of the equipment in advance. In this paper, we present Mahalanobis distance (MD) based fault detection method for steam boiler tube in TPP. In the MD-based method, it is supposed that abnormal data samples are far away from normal samples. Using multivariate samples collected from normal target system, mean vector and covariance matrix are calculated and threshold value of MD is decided. In a test phase, after calculating the MDs between the mean vector and test samples, alarm signals occur if the MDs exceed the predefined threshold. To demonstrate the performance, a failure case due to boiler tube leakage in 200MW TPP is employed. The experimental results show that the presented method can perform early detection of boiler tube leakage successfully.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.3
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• pp.351-359
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• 1996

We have investigated the effect of hydrogen plasma on the formation of InAs QDs (quantum dots) structure by using a CBE (chemical beam epitaxy)system equipped with ECR (electron cyclotron resonance) plasma source. It is confirmed that the formation of self-organized InAs-QDs on GaAs is started after the growth of InAs layer up to 2.6 ML (monolayer) with the irradiation of hydrogen plasma while it is started after 1.9 ML without hydrogen gas and hydrogen plasma through the observation of RHEED patterns. Density and size of the QDs formed at $T_{sub}=370^{\circ}C$ are $1.9{\times}10^{11}cm^{-2}$ and 17.7 nm without hydrogen plasma, and $1.3{\times}10^{11}cm^{-2}$ and 19.4 nm with hydrogen plasma, respectively. It is also observed from the PL(photoluminescence) measurement on InAs-QDs that red shift in PL peak energy and broadening in FWHM (full width at half maximum)of PL peak caused by the effects of hydrogen plasma on the increment of size and its distribution. These effects of hydrogen plasma are considered as a act of atomic hydrogen which enhances the layer-growth of InAs on GaAs resulted from the relief of misfit strain between GaAs substrate and InAs.

• Journal of the Korean Geotechnical Society
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• v.31 no.8
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• pp.5-15
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• 2015

One-dimensional rainfall laboratory tests using gneissic weathered soil were conducted to investigate effect of antecedent rainfall on infiltration characteristics. Experimental results using samples from Chuncheon and Chungju sites showed that rainfall onto the ground surface decreased initial negative pore water pressure of unsaturated soils, which recovered gradually after the end of rainfall. Rainfall intensity increases water infiltration rate, and infiltration rate during main rainfall is faster than that of the preceding rainfall. It is considered that higher water saturation after antecedent rainfall increases water infiltration rate during main rainfall. In particular, Chungju sample with higher clay content had slower recovery of negative pore water pressure and infiltration rate. Numerical results using finite element slope stability analysis showed that reduction of initial negative pore pressure due to rainfall infiltration deteriorates slope stability, and diffusion of pore water pressure after the end of rainfall further reduces FS of the slope in the short term. Main rainfall after prior rainfall further reduced factor of safety of the unsaturated slope. Pattern of antecedent rainfall has a significant impact on the magnitude and distribution of initial pore water pressure in unsaturated soils which are controlling factor to assess factor of safety of unsaturated slope during rainfall.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1C
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• pp.102-110
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• 2004

In this paper, we propose a VLSI structure of real-time image compression and reconstruction processor using 2-D discrete wavelet transform and implement into a hardware which use minimal hardware resource using ASIC library. In the implemented hardware, Data path part consists of the DWT kernel for the wavelet transform and inverse transform, quantizer/dequantizer, the huffman encoder/huffman decoder, the adder/buffer for the inverse wavelet transform, and the interface modules for input/output. Control part consists of the programming register, the controller which decodes the instructions and generates the control signals, and the status register for indicating the internal state into the external of circuit. According to the programming condition, the designed circuit has the various selective output formats which are wavelet coefficient, quantization coefficient or index, and Huffman code in image compression mode, and Huffman decoding result, reconstructed quantization coefficient, and reconstructed wavelet coefficient in image reconstructed mode. The programming register has 16 stages and one instruction can be used for a horizontal(or vertical) filtering in a level. Since each register automatically operated in the right order, 4-level discrete wavelet transform can be executed by a programming. We synthesized the designed circuit with synthesis library of Hynix 0.35um CMOS fabrication using the synthesis tool, Synopsys and extracted the gate-level netlist. From the netlist, timing information was extracted using Vela tool. We executed the timing simulation with the extracted netlist and timing information using NC-Verilog tool. Also PNR and layout process was executed using Apollo tool. The Implemented hardware has about 50,000 gate sizes and stably operates in 80MHz clock frequency.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.2
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• pp.93-100
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• 2009

This paper presents a step up four channel DC-DC converter using charge pump voltage doubler structure. Our goal is to design and implement DC-DC converter for capacitive SP4T RF MEMS switch in front end module in wireless transceiver system. Charge pump structure is small and consume low power 3.3V input voltage is boosted by DC-DC Converter to $11.3{\pm}0.1V$, $12.4{\pm}0.1V$, $14.1{\pm}0.2V$ output voltage With 10MHz switching frequency. By using voltage level shifter structure, output of DC-DC converter is selected by 3.3V four channel selection signals and transferred to capacitive MEMS devices. External passive devices are not used for driving DC-DC converter. The total chip area is $2.8{\times}2.1mm^2$ including pads and the power consumption is 7.52mW, 7.82mW, 8.61mW.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.5
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• pp.8-15
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• 2002

We optimally designed the VCO(voltage-controlled oscillator) with spiral inductor using the MOSIS HP 0.5${\mu}{\textrm}{m}$ CMOS process. With the developed SPICE model of spiral inductor, the quality factor of spiral inductor was maximized at the operating frequency by varying the layout parameters, e.g., metal width, number of turns, radius, space of the metal lines. For the operation frequency of 2㎓, the inductance of about 3nH, and the MOSIS HP 0.5 CMOS process with the metal thickness of 0.8${\mu}{\textrm}{m}$, oxide thickness of 3${\mu}{\textrm}{m}$, the optimal width of metal lines is about 20${\mu}{\textrm}{m}$ for the maximum Quality factor. With the optimized spiral inductor, the VCO with LC tuning tank was designed, fabricated and measured. The measurements were peformed on-wafer using the HP8593E spectrum analyzer. The oscillation frequency was about 1.610Hz, the frequency variation of 250MHz(15%) with control voltage of 0V - 2V, and the phase noise of -108.4㏈c(@600KHz) from output spectrum.

• Journal of Broadcast Engineering
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• v.25 no.3
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• pp.325-337
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• 2020

Versatile Video Coding (VVC) is a new video coding standard that is being developed by the Joint Video Experts Team of ISO/IEC/ITU-T and it has adopted various technologies including screen content coding tools. Screen contents have a feature that blocks are likely to have diagonal edges like character regions. If triangular partitioning coding is allowed for screen contents having such the feature, coding efficiency would increase. This paper proposes a intra prediction method using triangular partitioning prediction for screen content coding. Similar to the Triangular Prediction Mode of VVC that supports the triangular partitioning prediction, the proposed method derives two prediction blocks using Horizontal and Vertical modes and then it blends the predicted blocks applying masks with triangle shape to generate a final prediction block. The experimental results of the proposed method showed an average of 1.86%, 1.49%, and 1.55% coding efficiency in YUV, respectively, for VVC screen content test sequences.