• KIPS Transactions on Software and Data Engineering
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• v.5 no.8
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• pp.377-384
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• 2016

Our goal is to build the system which collects tweets from Twitter, analyzes the sentiment of each tweet, and helps users build a sentiment tagged corpus semi-automatically. After collecting tweets with the Twitter API, we analyzes the sentiments of them with a sentiment dictionary. With the proposed system, users can verify the results of the system and can insert new sentimental words or dependency relations where sentiment information exist. Sentiment information is tagged with the JSON structure which is useful for building or accessing the corpus. With a test set, the system shows about 76% on the accuracy in analysing the sentiments of sentences as positive, neutral, or negative.

• Bulletin of the Korean Chemical Society
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• v.29 no.10
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• pp.1937-1940
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• 2008

The P1 duplex of Tetrahymena group I ribozyme is the important system for studying the conformational changes in folding of ribozyme. The formation of the P1 duplex between IGS and substrate RNA and the catalytic activity of ribozyme require a variety of metal ions such as $Mg^{2+}$ and $Mn^{2+}$. In order to investigate the effect of the $Mg^{2+}$ concentration on the conformation of the P1 duplex, the NMR study was performed as a function of $Mg^{2+}$ concentration. This study revealed that the less stable AU-rich region formed duplex at $50{^{\circ}C}$ under high $Mg^{2+}$ concentration condition but melts out under low $Mg^{2+}$ concentration condition. It was also found that in the active conformation under 10 mM $MgCl_2$ condition, the unstable central G${\cdot}$U wobble pair maintains the significant base pairing up to $50{^{\circ}C}$. This study provides the information of the unique feature of the P1 duplex structure and the roll of $Mg^{2+}$ ion on the formation of the active conformation.

• Fibers and Polymers
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• v.5 no.3
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• pp.198-203
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• 2004

Composite films were prepared by casting the solution of polyacrylonitrile (PAN) and single wall nanotube (SWNT) in DMF subsequent to sonication. The SWNTs in the films are well dispersed as ropes with 20-30 nm thickness. Moreover, AFM surface image of the composite film displays an interwoven fibrous structure of nanotubes which may give rise to conductive passways and lead to high conductivity. The polarized Raman spectroscopy is an ideal characterization technique for identification and the orientation study of SWNT. The well-defined G-peak intensity at 1580 $cm^{-1}$shows a dependency on the draw ratio under cross-Nicol. The degree of nanotube orientation in the drawn film was measurable from the sine curve obtained by rotating the drawn film on the plane of cross-Nicol of polarized Raman microscope. The threshold loading of SWNT for electrical conductivity in PAN is found to be lower than 1 wt% in the composite film. The electrical conductivity of the SWNT/PAN composite film decreased with increasing of draw ratio due to the collapse of the interwoven fibrous network of the nanotubes with uniaxial orientation.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.11
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• pp.43-52
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• 1997

Ultrasonic sensors are widely employed in detecting range to a target by the virtue of their low cost and simplicity. However, the sensor's measurements are corrupted by systematic errors due mainly to the dependency of sound speed upon surrounding conditions and random errors of uncertain origin. In this paper, we present the results of research carried out to reduce these errors for increasing the reliability of an untrasonic sensor system to be used in orbotic or other automated system's range finding. The sensor system designed herein is in a peuliar structure having a reference target and two receivers. Echoes from a small reference target placed at a known distance are used for compensating the variations of sound speed according to the changes of sensing conditions. Unlike existing ones, the technique proposed can compensate the effects of temperature or any other physical parameters without an additional sensor dedicated to the compensation. The measurements by two redundantly employed receivers are fused to reduce random errors in a statistical sense. The correlation of the signals from the receivers sharing a hardware in part is considered in the fusion process. The methodology desicribed in this paepr is conceptually simple, easy to be implemented, and effetive to increase the accuracy of the sensor measurements as experimental results confirm.

• The KIPS Transactions:PartA
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• v.10A no.5
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• pp.493-502
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• 2003

For increasing needs about web-based XML applications, there has been a lot of studies about WIDL, CDF and OSD that are related to XML. Especially, the OSD format describes software packages and their inter-dependencies that is widely used in a CDF file, IT uses different forms for representing relationships among software pakages, because there has not been proposed a method of object modeling about it until now. In this paper, we propose a modeling method for the OSD and CDF documents using UML relationships. It is a part of the project to merge XML, applications and convert thd OCD and CDF documents into an IML class diagram to generate OODB sheme. We can esily not only visualuze implementation and dependency relationships among software packages but also understand and transform logical structure of XML documents using modeling functions.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.165-168
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• 2002

As the demand for higher data-rate chip-to-chip communication such as memory-to-controller, processor-to-processor increases, low cost high-speed serial links\ulcorner become more attractive. This paper describes a 0.25-fm CMOS 1.6Gbps/pin 4-level transceiver using Stub Series Terminated Logic for high Bandwidth. For multi-gigabit/second application, the data rate is limited by Inter-Symbol Interference (ISI) caused by channel low pass effects, process-limited on-chip clock frequency, and serial link distance. The proposed transceiver uses multi-level signaling (4-level Pulse Amplitude Modulation) using push-pull type, double data rate and flash sampling. To reduce Process-Voltage-Temperature Variation and ISI including data dependency skew, the proposed high-speed calibration circuits with voltage swing controller, data linearity controller and slew rate controller maintains desirable output waveform and makes less sensitive output. In order to detect successfully the transmitted 1.6Gbps/pin 4-level data, the receiver is designed as simultaneous type with a kick - back noise-isolated reference voltage line structure and a 3-stage Gate-Isolated sense amplifier. The transceiver, which was fabricated using a 0.25 fm CMOS process, performs data rate of 1.6 ~ 2.0 Gbps/pin with a 400MHB internal clock, Stub Series Terminated Logic ever in 2.25 ~ 2.75V supply voltage. and occupied 500 * 6001m of area.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1806-1813
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• 2003

The stirred tank reactor is one of the most commonly used devices in industry for achieving mixing and reaction. Here we report on results obtained from the large eddy simulations of flow inside the tank performed using a spectral multi-domain technique. The computations were driven by specifying the impeller-induced flow at the blade tip radius. Stereoscopic PIV measurements (Hill et $al.^{(1)}$) along with the theoretical model of the impeller-induced flow (Yoon et $al.^{(2)}$) were used in defining the impeller-induced flow as superposition of circumferential, jet and tip vortex pair components. Large eddy simulation of flow in a stirred tank was carried out for the three different Reynolds numbers of 4000, 16000 and 64000. The effect of different Reynolds numbers is well observed in both instantaneous and time averaged flow fields. The instantaneous and mean vortex structures are identified by plotting an isosurfaces of swirling strength for all Reynolds numbers. The Reynolds number dependency of the nondimeansional eddy viscosity, resolve scale and subgrid scale dissipations is clearly shown in this study.

• Korean Journal of Computational Design and Engineering
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• v.5 no.4
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• pp.347-358
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• 2000

The view dependency of typical spatial-partitioning based NC simulation methods is overcome by polygon rendering technique that generates polygons to represent the workpiece, thus enabling dynamic viewing transformations without reconstruction of the entire data structure. However, the polygon rendering technique still has difficulty in realizing real-time simulation due to unsatisfactory performance of current graphics devices. Therefore, it is necessary to develop a mesh decimation method that enables rapid rendering without loss of display quality. In this paper. we proposed a new mesh decimation algorithm thor a workpiece whose shape varies dynamically. In this algorithm, the 2-map data thor a given workpiece is divided into several regions, and a triangular mesh is constructed for each region first. Then, if any region it cut by the tool, its mesh is regenerated and decimated again. Since the range of mesh decimation is confined to a few regions, the reduced polygons for rendering can be obtained rapidly. Our method enables the polygon-rendering based NC simulation to be applied to the computers equipped with a wider range of graphics cards.

• Annual Conference on Human and Language Technology
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• 1994.11a
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• pp.181-186
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• 1994

변환 방식의 기계 변역이란 변환 규칙을 사용하여 원시 언어의 중간 단계 표현으로부터 목적 언어의 중간 단계 표현을 구하는 것이다. 변환 방식에는 규칙을 사용하는 변환과 예문을 기반으로 하는 변환이 있다. 규칙을 사용하는 변환시스템은 시스템의 확장성에 문제가 있는 반면에 예문을 기반으로 하는 변환 시스템은 견고하고 시스템의 확장성이 좋으며, 특정 영역에 대한 변역에 매우 적합하다는 등의 장점을 가진다. 예문을 기반으로 하는 변환 시스템에서 예문의 표현은 문장 단위로 할 수도 있고, 혹은 구문 단위로 할 수도 있다. 예문을 문장 단위로 정의 할 경우에는 매우 다양한 형태의 문장들을 포함해야 하므로 예문의 갯수가 매우 많아지며, 그다지 견고하지 못하게 된다. 반면에 구문 단위를 예문으로 하는 경우는 응용성이 좋고 견고하지만, 부분적으로 변역된 여러 구문들을 결합해야 하는 문제가 있다. 이러한 결합 문제를 해결하기 위한 한-영 예문의 대응 함수를 정의하고, 이 결합 함수를 사용하여 정의한 예문을 통하여 호텔 영역에서의 한-영 변환을 하는 시스템을 구현하였다.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.59.2-59.2
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• 2010

The structures of the protoplanetary nebula have been examined under various conditions of the stellar wind and the mass distribution of the nebula by assuming that the nebula is steady and geometrically thick. T Tauri stars commonly accompany with disks as well as the stellar wind. Therefore, the nebula around T Tauri stars should be influenced by the stellar wind. The results are summarized as follows ; The height of the geometrical surface of the nebula is suppressed by the dynamical pressure of the wind but depends very weakly on the wind strength. The surface becomes higher slightly when the wind strength becomes weaker. Furthermore, the dependency of the nebular height on the mass distribution of the nebula is also weak. As a natural result of the above, the temperature distribution in the nebula is insensitive to the wind strength and the mass distribution of the nebula, too. Thus, we can conclude that the temperature and geometrical surface height of the nebula under the stellar wind does not depend on neither the wind properties nor the mass distribution of nebula.