• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.2
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• pp.1-11
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• 1998

The 4WS system is usually developed to improve the maneuverability at low speed and the straight line stability at high speed, but it is found to have the severe understeer characteristics at high speed. Therefore a 4WS vehicle requires to turn the steering wheel much more than a 2WS vehicle at high speeds even a driver goes through the same curved road. In this study, to enhance the cornering performance of the 4WS vehicle at high speed, a DYC 4WS system is proposed based on the nonlinear 4WS system and direct yaw moment control system. Especially the proposed DYC 4WS system is able to realize a zero side slip angle for vehicles and a cornering performance similar to the 2WS vehicle at high speed.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.5
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• pp.639-646
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• 2015

The effects of Saccharomyces cerevisiae supplementation ($6.6{\times}10^8cfu$) and anhydrous ammonia treatment (3%) of wheat straw (WS) were investigated on in-situ dry matter (DM) degradability, and on rumen fermentation and growth performance of lambs. Rumen-fistulated Menemen sheep fed a diet with and without live yeast were used to assess the DM degradability characteristics of WS and ammonia-treated wheat straw ($WS_{NH3}$). Twenty-six yearling Menemen male lambs were fed in four groups. Lambs of control group (WS) received untreated WS without supplemental yeast, whereas other three groups were fed WS treated with anhydrous ammonia ($WS_{NH3}$ group), untreated WS and yeast (WS+YEAST group) or WS treated with anhydrous ammonia and yeast ($WS_{NH3}$+YEAST group). Supplemented live yeast (4 g/d) was added in the diet. Lambs were offered untreated or ammonia treated WS ad-libitum and concentrate was fed at 1% of live body weight. The degradability of the water-insoluble (fraction B) was significantly increased by all of the treatment groups. Potential degradability (A+B), effective DM degradability's (pe2, pe5, and pe8) and average daily weight gain increased only in $WS_{NH3}$+YEAST group (p<0.05). Voluntary DM intake was not increased by the treatments (p>0.05), but voluntary metabolizable energy and crude protein intake were increased by $WS_{NH3}$ and by $WS_{NH3}$+YEAST (p<0.05). Average daily rumen pH was not affected by any of the treatments, but average daily $NH_3$-N was significantly higher in the $WS_{NH3}$ and $WS_{NH3}$+YEAST groups, and total volatile fatty acids were significantly higher in the WS+YEAST and $WS_{NH3}$+YEAST groups. In conclusion, the improvement of feed value of WS was better by the combination of ammonia-treatment and yeast supplementation compared to either treatment alone.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.173-179
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• 1998

The processing conditions for the synthesis of platelet WS$_2$ lubricant powder through the solid-gas reaction were optimized. The tungsten and sulfur powders were sealed in a vacuum of 10$^{-6}$ torr, prior to heat-treating at 850$\circ$C for 8 days. The react~on product showed the well-developed platelet WS$_2$ powder with an average size of 3.8 $\mu$m. The synthesized WS$_2$ powder was coated on the commercial deep grooved ball bearing (No. 6203) to examine the effects of WS$_2$ coating layer on the noise and endurance of the ball bearing. The level of noise obtained from WS$_2$ coated-ball bearing was higher (56 dB) than the value occurred in the case of greece (37 dB). The life-time of the ball-bearing assembled after coating WS$_2$ powder increased 50 times compared to the non-coated bali-bearing.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.424-426
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• 2004

웹서비스란 XML 포맷의 벤더 중립적인 표준을 따라 웹에 산재한 웹 애플리케이션들을 통합하는 새로운 분산 컴퓨팅 기술이다. 웹서비스를 이용해서 비즈니스 로직을 바탕으로 유용한 서비스를 제공하는 새로운 비즈니스 프로세스를 구현하기 위해서 기존의 웹서비스를 조합하여 비즈니스 프로세스를 기술하는 웹서비스 컴포지션 스펙이 제안되었다. IBM과 Microsoft에서는 BPEL4WS, Sun에서는 WSCI, BPMI.org에서는 BPML을 제안하였는데, 그 중에 BPEL4WS와 BPML은 기업 내부 시스템에서 사용되는 실행 가능한 비즈니스 프로세스를 기술한다. 본 논문에서는 실행 가능한 비즈니스 프로세스를 위한 이 두 스펙간의 상호 운영성을 증대하기 위해서 BPEL4WS와 BPML간의 상호 변환 알고리즘을 제안한다. 예를 들어 BPEL4WS 구현 시스템에서 BPEL4WS에서 BPEL4WS로의 변환 알고리즘을 이용하여 BPEL4WS 뿐만 아니라 BPML로 기술된 비즈니스 프로세스를 참조할 수 있고, BPEL4WS에서 BPML로 변환 알고리즘을 이용하여 BPEL4WS 구현 시스템에서 사용 중인 비즈니스 프로세스 인스턴스를 BPML 프로세스로 출력하여 BPML 구현 시스템에서 사용할 수 있다.

• Korean Journal of Organic Agriculture
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• v.24 no.2
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• pp.253-262
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• 2016

The SS (Bacillus subtilis 10%), WS (Microbial extract 70%), and DS (Sulfur 78%) agents were selected by mycelial growth inhibitory effect test against kiwifruit soft rot pathogen (B. dothidea) with 11 kinds of environment-friendly agricultural materials on PDA medium for 10 days. They showed at 94.2%, 65.2%, 58.9%, respectively. The control value of WS and SS agents were better than DS in storage experiment. It was effective SS and WS single application, DS-WS and WS-SS alternate application in the field trial.

• Journal of Surface Science and Engineering
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• v.45 no.1
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• pp.37-42
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• 2012

$WS_2$ powder was added to the Cu/Sn bond metal of diamond micro-blades for machining of semi-conductor and IC chips to improve cutting efficiency. The effect of $WS_2$ additive on cutting efficiency was investigated and compared with the micro-blades with $MoS_2$ developed in previous research. Flexural strength, frictional coefficient, and wear resistance of blades decreased with $WS_2$ but wear depth increased. It was found that the blades including $WS_2$ consumed less momentary energy than the blades containing $MoS_2$ during dicing test. Micro-blades containing $WS_2$ exhibited lower flexural strength than the blades with $MoS_2$ resulting from higher amount of sintering defects relevant to the less effectiveness of $WS_2$ on fluidity. The effect of $WS_2$ and $MoS_2$ on fluidity during sintering was analyzed in terms of mismatching degree between the longitudinal direction of lubricant particles and the perpendicular direction to the compact loading. The blade with 8.1 vol.% of $WS_2$ showed the best cutting efficiency.

• Journal of the Korea Safety Management & Science
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• v.13 no.2
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• pp.195-202
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• 2011

The study focuses on the Repeated Measurements Design (RMD) which observations are periodically made for identical subjects within definite time periods. One of the purposes of this design is to monitor and keep track of replicated records within regular period over years. This paper also presents the classification models of RMD that is developed according to the number of factors in Between-Subject (BS) variates and Within-Subject (WS) variates. The types of models belong to each number of factors: One factor is 0BS 1WS. Two factors are 1BS 1WS and 0BS 2WS. Three factors are 1BS 2WS and 2BS 1WS. Lastly, the four factors include model of 2BS 2WS In addition, the study explains the generation mechanism of models for RMD using Generalizability Design (GD). GD is a useful method for practitioners to identify linear model of experimental design, since it generates a Venn diagram. Lastly, the research develops three types of 1BS 2WS RMDs with crossed factors and nested factors. Those are random models, mixed models and fixed models and they are presented by using Generalizability Design, $(S:A{\times}B){\times}C$. Moreover, the example of applications and its implementation steps of models developed in the study are presented for better comprehension.

• Journal of the Korea Convergence Society
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• v.3 no.4
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• pp.35-44
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• 2012

In this study, a simulation program is developed in order to investigate non steady-state cornering performance of 6WD/6WS special-purpose vehicles. 6WD vehicles are believed to have good performance on off-the-road maneuvering and to have fail-safe capabilities. But the cornering performances of 6WS vehicles are not well understood in the related literature. In this paper, 6WD/6WS vehicles are modeled as a 18 DOF system which includes non-linear vehicle dynamics, tire models, and kinematic effects. Then the vehicle model is constructed into a simulation program using the MATLAB/SIMULINK so that input/output and vehicle parameters can be changed easily with the modulated approach. Cornering performance of the 6WS vehicle is analyzed for brake steering and pivoting, respectively. Simulation results show that cornering performance depends on the middle-wheel steering as well as front/rear wheel steering. In addition, a new 6WS control law is proposed in order to minimize the sideslip angle. Lane change simulation results demonstrate the advantage of 6WS vehicles with the proposed control law.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.3
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• pp.76-85
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• 1997

The understeer characteristics of four wheel steering system(4WS system) in a high speed region have a negative effect upon the yaw velocity, leading to a decrease in the handling ability of vehicle. As a result, even if the side slip angle of vehicle can be kept up a minimum, a driver must compensate a decrease in yaw velocity by increasing the steering wheel angle in order to track the desired vehicle path. In this study, to keep the side slip angle of vehicle at zero and achieve a suitable yaw velocity in vehicle motion, a full active 4WS system(FA 4WS system) with actively steerable front and rear wheels is presented based on a nonlinear vehicle model and a model following control of yaw velocity. And the analysis results show the fat that, besides the excellent stability of vehicle, the FA 4WS system is able to realize better handling performance of vehicle than the previous 4WS systems in the high speed region.

• Communications of the Korean Mathematical Society
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• v.23 no.3
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• pp.313-324
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• 2008

Molodtsov [8] introduced the concept of soft set as a new mathematical tool for dealing with uncertainties that is free from the difficulties that have troubled the usual theoretical approaches. In this paper we apply the notion of soft sets by Molodtsov to the theory of subtraction algebras. The notion of soft WS-algebras, soft subalgebras and soft deductive systems are introduced, and their basic properties are derived.