• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.8
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• pp.126-132
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• 1995

The electrical stress of short channel polycrystalline silicon (poly-Si) thin film transistor (TFT) has been investigated. The device characteristics of short channel poly-Si TFT with 5$\mu$m channel length has been observed to be significantly degraded such as a large shift in threshold voltage and asymmetric phenomena after the electrical stress. The dominant degradation mechanism in long channel poly-Si TFT's with 10$\mu$m and 20$\mu$m channel length respectively is charage trappling in gate oxide while that in short channel device with 5.mu.m channel length is defect creation in active poly-Si layer. We propose that the increased defect density within depletion region near drain junction due to high electric field which could be evidenced by kink effect, constitutes the important reason for this significant degradation in short channel poly-Si TFT. The proposed model is verified by comparing the amounts of the defect creation and the charge trapping from the strechout voltage.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.99.1-99.1
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• 2011

Reactant mixing has a critical role in ensuring reformate quality and an important design objective is to achieve sufficiently complete mixture of reactants. For that purpose it is required to understand the coupled transport-kinetics phenomena in the mixing region. Three-dimensional computational fluid dynamics model was developed and validated in previous works. The mixing characteristics in various alternatives of a prototype mixing chamber were compared, and then a reduced reaction kinetics was applied to two extreme designs for investigating the impact of gas-phase reactions. Both designs did not reach threshold ethylene mole fraction of 0.001, but surprisingly more ethylene was generated in the design having better mixing characteristics. The presentation will deliver the development process of coupled transport and kinetics model briefly and the detailed information about the mixing characteristics and gas-phase reactions in two mixer designs.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.357-364
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• 2015

In this work, we investigate the quantum effects exhibited from ultra-thin GAA(gate-all-around) Nanowire FETs for Sub 14nm Technology. We face designing challenges particularly short channel effects (SCE). However traditional MOSFET SCE models become invalid due to unexpected quantum effects. In this paper, we investigated various performance factors of the GAA Nanowire FET structure, which is promising future device. We observe a variety of quantum effects that are not seen when large scale. Such are source drain tunneling due to short channel lengths, drastic threshold voltage increase caused by quantum confinement for small channel area, leakage current through thin gate oxide by tunneling, induced source barrier lowering by fringing field from drain enhanced by high k dielectric, and lastly the I-V characteristic dependence on channel materials and transport orientations owing to quantum confinement and valley splitting. Understanding these quantum phenomena will guide to reducing SCEs for future sub 14nm devices.

• 전기의세계
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• v.23 no.5
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• pp.47-53
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• 1974

The electrical cardiac pacemaker model described in this paper simulates the most important functional properies of cardiac pacemaker cells. It is a minimum-parameter model which has a simple relaxation oscillator circuit as its main element. The electrical cardiac pacemaker model is analyzed in detail in order to show that its characteristic is similar to that of cardiac pacemaker cells. The main feature of the model is the possibility of controlling the time course phase 4 depolarization, the threshold level and the maximum level of repolarization, the rate of cardiac pacemaker. Emphasis is placed on phenomena of acceleration and frequency entrainment. This particular pacemaker model is very useful for the study of interactions between cardiac pacemakers and the description of the mechanism of arrhythmias.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1442-1444
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• 1994

The short channel poly-Si TFT is important in aspect of transistor characteristics, packing density and aperture ratio. In this paper, we have reported the degradation phenomena of short channel poly-Si TFT's which had significantly degraded device parameters, such as threshold voltage shift and a great asymmetric degradation, due to gate and drain electrical stress. The reduced effective channel length and expanded depletion region may be the main reason of these significant device parameters.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.1
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• pp.86-92
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• 2009

We fabricated the charged particle type display using opposite-charged two toner particles. The particles were composed of polymer, colorant($TiO_2$, carbon black) and external additives(nano-sized silica and so on). In fabrication process we controlled the putting layers of this toner particles on the inner panel. To get the effect of number of layers ($1{\sim}3$), we measured the threshold, driving and breakdown voltages, reflectivity, viewing angle, and color characteristics using RT-300 anisotropic scattering system. We ascertained that these voltages are increased with increasing of layers of particles. Cell gap between electrodes must be enlarged with increment of layers and the size of particles. The lumping phenomena of particles at near of the rib observed by optical system with same CIE values.

• Structural Engineering and Mechanics
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• v.29 no.4
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• pp.433-453
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• 2008

The equation of motion of a one way (vertical) spanning strip wall, as an assembly of two rigid bodies, is presented. Only one degree of freedom is needed to completely describe the wall response as the bodies are assumed to be perfectly rectangular and are allowed to rock but not to slide horizontally. Furthermore, no arching action occurs since vertical motion of the upper body is not restrained. Consequently, the equation of motion is nonlinear, with non constant coefficients and a Coriolis acceleration term. Phenomena associated with overburden to self weight ratio, motion triggering, impulsive energy dissipation, amplitude dependency of damping and period of vibration, and scale effect are discussed, contributing to a more complete understanding of experimental observations and to an estimation of system parameters based on the wall characteristics, such as intermediate hinge height and energy damping, necessary to perform nonlinear time history analyses. A comparison to a simple standing, or parapet, wall is developed in order to better highlight the characteristics of this assembly.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3643-3652
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• 2021

Sizing the tube inlet orifice of a Once-Through Steam Generator (OTSG) is important to protect the integrity of the tubes from thermal cycling and vibration wear. In this study, a new sizing criterion is proposed for the tube inlet orifice to suppress the parallel channel instability in an OTSG. A perturbation method is used to capture the essential parts of the thermal-hydraulic phenomena of the parallel channel instability. The perturbation model of the heat transfer regime boundaries is identified as a missing part in existing models for sizing the OTSG tube inlet orifice. Limitations and deficiency of the existing models are identified and the reasons for the limitations are explained. The newly proposed model can be utilized to size the tube inlet orifice to suppress the parallel channel instability without excessive engineering margin.

• Atmosphere
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• v.24 no.3
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• pp.445-456
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• 2014

A real-time quality control system for meteorological data (air temperature, air pressure, relative humidity, wind speed, wind direction, and precipitation) measured by an integrated meteorological sensor has been developed based on comparison of quality control procedures for meteorological data that were developed by the World Meteorological Organization and the Korea Meteorological Administration (KMA), using time series and statistical analysis of a 12-year meteorological data set observed from 2000 to 2011 at the Incheon site in Korea. The quality control system includes missing value, physical limit, step, internal consistency, persistence, and climate range tests. Flags indicating good, doubtful, erroneous, not checked, or missing values were added to the raw data after the quality control procedure. The climate range test was applied to the monthly data for air temperature and pressure, and its threshold values were modified from ${\pm}2{\sigma}$ and ${\pm}3{\sigma}$ to ${\pm}3{\sigma}$ and ${\pm}6{\sigma}$, respectively, in order to consider extreme phenomena such as heat waves and typhoons. In addition, the threshold values of the step test for air temperature, air pressure, relative humidity, and wind speed were modified to $0.7^{\circ}C$, 0.4 hPa, 5.9%, and $4.6m\;s^{-1}$, respectively, through standard deviation analysis of step difference according to their averaging period. The modified quality control system was applied to the meteorological data observed by the Weather Information Service Engine in March 2014 and exhibited improved performance compared to the KMA procedures.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.10
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• pp.3378-3393
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• 2014

We have witnessed the rapid development of information technology in recent years. One of the key phenomena is the fast, near-exponential increase of data. Consequently, most of the traditional data classification methods fail to meet the dynamic and real-time demands of today's data processing and analyzing needs--especially for continuous data streams. This paper proposes an improved incremental learning algorithm for a large-scale data stream, which is based on SVM (Support Vector Machine) and is named DS-IILS. The DS-IILS takes the load condition of the entire system and the node performance into consideration to improve efficiency. The threshold of the distance to the optimal separating hyperplane is given in the DS-IILS algorithm. The samples of the history sample set and the incremental sample set that are within the scope of the threshold are all reserved. These reserved samples are treated as the training sample set. To design a more accurate classifier, the effects of the data volumes of the history sample set and the incremental sample set are handled by weighted processing. Finally, the algorithm is implemented in a cloud computing system and is applied to study user behaviors. The results of the experiment are provided and compared with other incremental learning algorithms. The results show that the DS-IILS can improve training efficiency and guarantee relatively high classification accuracy at the same time, which is consistent with the theoretical analysis.