• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.12
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• pp.79-90
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• 2000

In this paper, a high-performance floating point unit, which is suitable for high-performance superscalar microprocessors and supports IEEE 754 standard, is designed. Floating-point arithmetic unit (AU) supports all denormalized number processing through hardware, while eliminating the additional delay time due to the denormalized number processing by proposing the proposed gradual underflow prediction (GUP) scheme. Contrary to the existing fixed-radix implementations, floating-point divide/square root unit adopts a new architecture which determines variable length quotient bits per cycle. The new architecture is superior to the SRT implementations in terms of performance and design complexity. Moreover, sophisticated exception prediction scheme enables precise exception to be implemented with ease on various superscalar microprocessors, and removes the stall cycles in division. Designed floating-point AU and divide/square root unit are integrated with and instruction decoder, register file, memory model and multiplier to form a floating-point unit, and its function and performance is verified.

• The KIPS Transactions:PartD
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• v.13D no.3 s.106
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• pp.437-444
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• 2006

A chaos cipher system that focuses on the stream cipher system has a demerit that the longer the text is, the slower the speed of the encryption and description and the transmission and reception. On this study, we designed the cipher web mail system showing much better capabilities than the existing web mail system as the text is longer. In the embodiment of the cipher web mail system, we developed the key stream, the encryption and description of the text and the inside and outside mail viewer and so on. After the efficiency test, it was valued high in the respect of the speed of the encryption and description and the transmission and reception. And it made up for the defect of the stream cipher system. We expect that we can use it through the persistent applied study in the server system security, the file security, the security of the internet information, the protection of the e-commerce system information and other fields based on the cipher technique as the wide use cipher system that can replace the block cipher system.

• Journal of Advanced Navigation Technology
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• v.26 no.5
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• pp.331-337
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• 2022

The length of optical fiber in dispersion-managed link combined with optical phase conjugation to compensate for signal distortion caused by chromatic dispersion and nonlinear Kerr effect is a major factor determining the compensation effectiveness. The dispersion-managed link consists of several fiber spans in which standard single mode fiber and dispersion compensating fiber are arranged. In this paper, the compensation effect in the link that changes residual dispersion per span only by adjusting the length of one type of optical fiber, which is different in the first half link and the second half link with respect to optical phase conjugator (OPC), has been investigated. It was confirmed that the best compensation for 960 Gb/s wavelength division multiplexed signal could be obtained in the dispersion-managed link, in which the cumulative dispersion profile is symmetric around the OPC, and the cumulative dispersion amount is all positive in the first half, and all the cumulative dispersion amount is distributed negatively in the second half.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.3
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• pp.437-444
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• 2000

In this paper, we propose a method that directly converts 3D CAD files for handheld phones designed by a commercial CAD S/W, PATRAN, to FDTD modeling with 1mm resolution. To qualify the accuracy of this method, we compared the calculation of radiation pattern using 3D transient far zone transformation with the measured results by gain comparison method in anechoic chamber and the difference is less than 0.5 dB. The calculation of magnetic field distributions on the front of handheld phones has been done to find a factor contributes to SAR. The result showed up the H-field in the width direction of the phone gives more dominant effect than the field in the length or inside to the front direction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.4
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• pp.380-386
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• 2003

As Internet is spreaded widely, the virtual communities among people with the same interest and hobby are dynamically created. The exchange of fruitful opinion and information makes them to be closed, not only with the help of the messaging system but also wireless terminals. The messaging system is a core technology supporting the global community services like chatting, messenger, short message services, and file sharing services. The paper focus on the design of software architecture for messaging system and the engineering model for QoS support.

• 순환기질환의공학회:학술대회논문집
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• 2005.12a
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• pp.25-26
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• 2005

동맥경화의 재발생 위치는 속도와 전단응력 등과 같은 혈류역학의 인자들의 영향을 많이 받는 혈관형태를 가진 영역이다. 이러한 결과는 관상동맥에 동맥경화의 발생빈도를 조사한 결과와 일치하고 있으며, 즉 좌전 하행지, 회선지, 및 우관동맥 등의 동맥경화성 병변 발생빈도에서 좌전하행지가 가장 많은 빈도를 나타낸다. 따라서 동맥경화의 발생 및 재형성은 혈관의 동맥경화성 위험지역의 형태적 특징, 즉, 분지부의 위치, 길이, 각도의 변화 등에 따라 달라질 수 있음을 시사한다. 동일한 관상동맥이더라도 동맥경화의 발생이 용이한 형태가 있는데, 혈관의 형태학적 특성에 따란 혈류역학적 특성이 달라지고 동맥경화가 발생할 수 있는 가능성이나 진행과정이 차이가 날 수 있음을 말한다. 특히 임계치를 넘는 고전단응력은 혈관내피세포를 파괴하거나 손상을 주며, 반대로 임계치 미만의 저전단응력은 혈류의 정체시간을 길게 하여 양쪽 모두 동맥경화성 생물학적 반응을 유발 할 수 있며, 고전단응력과 저전단응력의 빈번한 맥동성 변화작용으로 혈관이 손상될 수 있는 한계범위를 넘어서게 될 때 내피세포의 방어체계를 파괴시키거나 혈관성형술후의 신내포세포 형성과정에서 생물학적 활성반응을 촉진하게 되는 환경을 제공하게 되어 동맥경화를 촉진한다고 할 수 있다. 즉 임계치 이상의 고전단응력이 나타나는 형태와 입구경계조건이 발생되면 내피세포 손상에 따른 혈전 현상의 발생가능성이 높아지며, 임계치 미만의 저전단응력이 발생되면 동맥경화성 죽상반 재형성에 영향을 미치게 한다. 결론적으로 동맥경화의 재발생의 기전은 변형된 혈관의 형태학적인 차이와 위치에 따라 서로 다른 혈류역학적 유발할 수 있는 물리적 환경을 제공하는 데에서 출발한다고 할 수 있다.$8.0{\sim}8.3$으로 알카리 쪽으로 이동하였다. 파일롯트 규모로 본 고정화 효소 충전탑(내경 30cm, 높이 85cm)에 의한 이성화당의 생산을 시도하였던바, 고정화 효소(350 IXIU/ml-R) 1리터가 30일동안에 약 293리터의 이성화당을 생산할 수 있는 것으로 나타났다.l plane에서 선수군(選手群)이 $62.7{\pm}7.36^{\circ}$로서 비선수군(非選手群)과 별(別) 차이(差異)가 없었고, horizontalplane에서는 선수군(選手群)이 $-23.5{\pm}7.2^{\circ}$로서 비선수군(非選手群)의 $-38.8{\pm}8.2^{\circ}$에 비(比)해 유의(有意)하게 높았으며 운동후(運動後) 양군(兩群) 모두 유의(有意)하게 높았다. QRS vector 길이에서 Frontal plane에서 선수군(選手群)이 $13.86{\pm}1.44\;mm$로서 비선수군(非選手群)의 $9.62{\pm}0.97\;mm$에 비(比)해 유의(有意)하게 높았으며 운동후(運動後)에도 유의(有意)하게 높았다. Horizontal plane에서도 선수군(選手群)이 $19.82{\pm}2.10\;mm$로서 비선수군(非選手群)의 $16.90{\pm}1.39\;mm$에 비(比)해 유의(有意)하게 높았고 운동후(運動後)에도 선수군(選手群)이 유의(有意)하게 높았다. 이상(以上)을 종합(綜合)해 보면 선수군(選手群)의 R파고(波高)가 비선수군(非選手群)에 비(比)해 운동후(運動後) 계속(繼續) 유의(有意)하게 높았고, $Rv_5$

• Journal of Advanced Navigation Technology
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• v.28 no.4
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• pp.552-558
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• 2024

In dispersion management, which involves additionally inserting a dispersion compensation fiber of an appropriate length to eliminate or reduce the chromatic dispersion of a single-mode fiber, determining the form of the dispersion map, which is the cumulative dispersion profile according to the transmission distance, is the most basic and important. In this paper, the various symmetric dispersion map based on trapezoids applied to dispersion-managed links combined with mid-span spectral inversion (MSSI), which compensates for the distortion caused by Kerr nonlinear effects through optical phase conjugation in the middle of the entire transmission link are proposed, and the effect of each dispersion map on distortion compensation of wavelength division multiplexed (WDM) signals is analyzed. Although the degree of compensation varies depending on the factors that determine the detailed shape of the proposed trapezoid-shaped dispersion map and RDPS (residual dispersion per span), overall, it was confirmed that distortion compensation for signals with a small extinction ratio was more effective than distortion compensation for WDM channel signals with a large extinction ratio.

• Restorative Dentistry and Endodontics
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• v.31 no.3
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• pp.179-185
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• 2006

This study was conducted to evaluate canal configuration after shaping by $ProTaper^{TM}$ with various rotational speed in J-shaped simulated resin canals. Forty simulated root canals were divided into 4 groups, and instrumented using by $ProTaper^{TM}$ at the rotational speed of 250, 300, 350 and 400 rpm. Pre-instrumented and post-instrumented images were taken by a scanner and those were superimposed. Outer canal width, inner canal width, total canal width, and amount of transportation from original axis were measured at 1, 2, 3, 4, 5, 6, 7 and 8 mm from apex. Instrumentation time, instrument deformation and fracture were recorded. Data were analyzed by means of one-way ANOVA followed by Scheffe's test. The results were as follows 1. Regardless of rotational speed, at the $1{\sim}2mm$ from the apex, axis of canal was transported to outer side of a curvature, and at 3~6 mm from the apex, to inner side of a curvature. Amounts of transportation from original axis were not sienifcantly different among experimental groups except at 5 and 6 mm from the apex. 2. Instrumentation time of 350 and 400 rpm was significantly less than that of 250 and 300 rpm (p<0.01). In conclusion the rotational speed of $ProTaper^{TM}$ files in the range of $250{\sim}400rpm$ does not affect the change of canal configuration, and high rotational speed reduces the instrumentation time. However appearance of separation and distortion of Ni-Ti rotary files can occur in high rotational speed.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.287-294
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• 2021

In order to expand facility agriculture and reduce greenhouse construction costs in reclaimed land, a greenhouse foundation method that satisfies economic feasibility and structural safety at the same time is required. As an alternative, the allowable bearing capacity and settlement were reviewed when the DCM(Deep cement mixing) method was applied among the soft ground reinforcement methods. To examine the applicability of the greenhouse foundation, the allowable bearing capacity and settlement were calculated by applying the theory of Terzaghi, Meyerhof, Hansen, and Schmertmann. In case of the diameter of 800mm and the width and length of the foundation of 4m, the allowable bearing capacity was 179kN/m² and the settlement was 7.25mm, which satisfies the required bearing capacity and settlement standards. The calculation results were verified through FEM(Finite element method) analysis using the Mohr-Coulomb material model. The allowable bearing capacity was 169kN/m² and the settlement was 2.52mm. The bearing capacity showed an error of 5.6% compared to calculated value, and the settlement showed and error of 65.4%. Through theoretical calculations and FEM analysis, it was confirmed that the allowable bearing capacity and settlement satisfies the design criteria as a greenhouse foundation when the width and length of the foundation were 4m. Based on the verified design values, it is expected to be able to present the foundation design criteria for greenhouses through empirical tests such as bearing capacity tests and long-term settlement monitoring.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.33-46
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• 2011

Since an e-mail has been an important mean of communication and information sharing, there have been much effort to classify e-mails efficiently by their contents. An e-mail has various forms in length and style, and words used in an e-mail are usually irregular. In addition, the criteria of an e-mail classification are subjective. As a result, it is quite difficult for the conventional text classification technique to be adapted to an e-mail classification efficiently. An e-mail classification technique in a commercial e-mail program uses a simple text filtering technique in an e-mail client. In the previous studies on automatic classification of an e-mail, the Naive Bayesian technique based on the probability has been used to improve the classification accuracy, and most of them are on an e-mail in English. This paper proposes the personalized recommendation technique of an email in Korean using a data mining technique of frequent patterns. The proposed technique consists of two phases such as the pre-processing of e-mails in an e-mail folder and the generating a profile for the e-mail folder. The generated profile is used for an e-mail to be classified into the most appropriate e-mail folder by the subjective criteria. The e-mail classification system is also implemented, which adapts the proposed technique.