• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1996년도 춘계학술대회논문집
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• pp.40-47
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• 1996

An upper bound solution of tube drawing process using a fixed tapered plug has been obtained , which reduces to an solution for tube sinking by setting friction factor between tube and plug at zero. Effects of various process paraments have been discussed based on the solution.

• 대한수학회논문집
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• 제13권1호
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• pp.29-36
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• 1998

We show that if M is a $II_1$-factor and a countable discrete group G acts outerly on M then Jones' index $[M:M^G]$ of a pair of $II_1^-factors is equal to the order $\mid$G$\mid$ of G. It is also shown that for a subgroup H of G Jones' index $[M^H:M^G]$ is equal to the group index [G:H] under certain conditions.

• Nuclear Engineering and Technology
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• 제33권1호
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• pp.102-110
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• 2001

In this work, the model predictive control method was applied to a linear model and a nonlinear model of steam generators. The parameters of a linear model for steam generators are very different according to the power levels. The model predictive controller was designed for the linear steam generator model at a fixed power level. The proposed controller at the fixed power level showed good performance for any other power levels by designed changing only the input-weighting factor. As the input-weighting factor usually increases, its relative stability does so. The steam generator has some nonlinear characteristics. Therefore, the proposed algorithm has been implemented for a nonlinear model of the nuclear steam generator to verify its real performance and also, showed good performance.

• Advances in concrete construction
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• 제6권6호
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• pp.611-629
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• 2018

The objective of present study is to investigate the effect of granulated blast furnace slag (GBS) as partial substitution of natural sand on behaviour of cement mortar. For this, the methods of factorial design with water cement (w/c) ratio and incorporation percentages of GBS as replacement of natural fine aggregate i.e., GBS(%) as factors are followed. The levels of factor w/c ratio are fixed at 0.4, 0.45, and 0.5 and the levels of factor GBS(%) are kept fixed as 0%, 20%, 40%, 60%, 80% and 100%. The compressive strength (CS) of mortar after 3, 7, 14, 28, 56 and 90 days, and water absorption (WA) are chosen as responses of the study. Analysis of variance (ANOVA) of experimental results has been carried out and those are illustrated by ANOVA tables, main effect and interaction plots. The results of study depict that the selected factors have substantial influence on the strength and WA of mortar. However, the interaction of factors has no substantial impact on CS and WA of mixes.

• ETRI Journal
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• 제23권4호
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• pp.177-189
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• 2001

Multicarrier DS-CDMA is an effective approach to combat fading and various kinds of interference. In this paper, we present an overlapped multicarrier DS-CDMA system, wherein each of the rate 1/M convolutionally-encoded symbols is also repetition coded and transmitted using overlapped multicarriers. However, since the frequency spectrums of successive carriers are allowed to overlap, the transmission bandwidth is more efficiently utilized. The effect of the overlapping percentage between successive carriers of a multicarrier DS-CDMA system on the performance is investigated to determine the overlapping percentage showing the best performance. We suggest two methods for sub-band overlapping variation. One is to allow variation of sub-band overlapping percentage when the total number of subcarriers is fixed. The other is to increase the number of sub-bands (the number of repetitions R) with fixed sub-band bandwidth. Given a total number of subcarriers MR, we show that the BER variation is highly dependent on the roll-off factor ${\beta}$ of a raised-cosine chip wave-shaping filter irrespective of convolutional encoding rate 1/M and repetition coding rate 1/R. We also analyze the possibility of reduction in total multi-user interference by considering the variation of both the roll-off factor ($0<{\beta}{\leq}1$) and the sub-band overlapping factor ($0<{\lambda}{\leq}2$), and show that the proposed system may outperform the multicarrier DS-CDMA system in [3].

• 한국산학기술학회논문지
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• 제12권7호
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• pp.3275-3279
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• 2011

유무선망 상호접속 서비스 제공을 통한 통화요금의 사업자별 배부가 서비스 설비원가에 의하여 많은 부분이 정의되는 점을 고려한다면 망 설비를 통하여 제공되는 서비스들의 통화량 기준에 의한 평가가 이루어져야 한다. 이러한 관점에서 이동통신망 설비를 음성, 데이터서비스를 위한 전용설비와 공통설비로 구분하고, 공통설비는 합리적 기준에 의한 서비스별 설비원가의 배부 방법의 도출이 필수적이다. 본 논문에서는 유럽 GSM 시스템에서 이용되고 있는 이동통신망 공통설비 원가 배부 방안 분석을 통하여 국내 CDMA 이동망의 공통설비 원가 배부를 위한 회선 음성 서비스와 패킷 데이터서비스간의 단일 통화량으로 계측하기 위한 서비스간 환산계수 방안을 도출하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.427-427
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• 2015

The storm water management and drainage relation are the key variable that plays a vital role on hydrological design and risk analysis. These require knowledge about spatial variability over a specified area. Generally, design rainfall values are expressed from the fixed point rainfall, which is depth at a specific location. Concurrently, determine the areal rainfall amount is also very important. Therefore, a spatial rainfall interpolation (point rainfall converting to areal rainfall) can be solved by areal reduction factor (ARF) estimation. In mainland of South Korea, for dam design and its operation, public safety, other surface water projects concerned about ARF for extreme hydrological events. In spite of the long term average rainfall (2,061 mm) and increasing extreme rainfall events, ARF estimation is also essential for Jeju Island's water control structures. To meet up this purpose, five fixed rainfall stations of automatic weather stations (AWS) near the "Hancheon Stream Watershed" area has been considered and more than 50 years of high quality rainfall data have been analyzed for estimating design rainfall. The relationship approach for the 24 hour design storm is assessed based on ARF. Furthermore, this presentation will provide an outline of ARF standards that can be used to assist the decision makers and water resources engineers for other streams of Jeju Island.

• 간호행정학회지
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• 제21권5호
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• pp.519-529
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• 2015

Purpose: This study was performed to identify perceptions on fixed night shift system and turnover intention of general hospital nurses and to explore a desirable application plan for a fixed night shift system. Methods: This study was a cross-sectional survey. Participants were 300 nurses working at one general hospital in GyeongGi-Do, Korea. Data were collected from November 3 to 7, 2014, with a structured questionnaires and analyzed using SPSS/PC ver 20.0 programs. Results: Of the participants 73.5% had thought about turnover because of night shifts and the preconditions for desirable fixed night shift system were a payment plan differentiated according to work conditions and an adequate number of nursing staff. Economic and administrative supports like 'raising extra-pay for night shift' and 'increasing the number of paid holidays' were very important for a desirable fixed night shift system. Conclusion: The results indicate that the most important factor for a desirable fixed night shift system to decrease nurses' turnover intention is economic and administrative support according to the needs of the nurses. So nursing managers need to find a desirable fixed night shift system considering nurses' demographic characteristics and organizational characteristics.

• 대한방사선기술학회지:방사선기술과학
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• 제4권1호
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• pp.45-53
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• 1981

In examinations of the stomach roentgenography, it is imperative to obtain adequate film density throughout all its different regions. Therefore, it is necessary to use more sophiscated exposure techniques. In order to achieve these purpose, the radiologic technologists must be measured abdominal thickness in variations with patient positions. In consideration of these problem, the author was made an experiment on correction method of kVp and mAs by abdominal thickness in roentgenography of the stomach. The results were summarized as follws: 1. When the patient in erect position, abdominal thickness was the most thickened at the level of 3cm inferior to umbilicus without regard to body habitus and it was the most thickened at the level of 3cm superior to umbilicus in prone and supine position. 2. As a result of measuring film density for stomach, the adequate film density was represented from 0.70 to 2.49 in erect position and $0.28{\sim}1.18$ in supine position, $0.5{\sim}2.45$ in prone position. 3. In order to obtain uniform film density in 1.25, the correction factor for kVp by abdominal thickness was represented average ${\pm}4.5kVp\;per\;{\pm}1cm$ in a fixed 50 mAs, and average ${\pm}3.9kVp\;per\;{\pm}1cm$ in a fixed 100mAs. 4. In order to obtain uniform film density in 1.25, the correction factor for mAs by abdominal thickness was represented average ${\pm}30.9%\;per\;{\pm}1cm$ in a fixed 80 kvp and ${\pm}26.9%\;per\;{\pm}1cm$ in a fixed 100kVp.

• 한국정보전자통신기술학회논문지
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• 제14권6호
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• pp.467-472
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• 2021

본 논문에서는 가스보일러에 사용되는 점화트랜스를 제작하여 전류와 역률, 소비전력을 측정하였다. 역률을 측정한 결과, 자체 제작된 점화트랜스는 외국제품에 비해 높았으며 소비전력은 낮게 측정되었다. 점화봉 간격을 2mm로 고정을 시키고 점화봉 길이가 30cm,500cm,1000cm일 때 3.45A, 14.5A, 16.2A로 측정되었다. 점화봉 간격을 4mm로 고정을 시키고 점화봉 길이가 30cm, 500cm, 1000cm일 때, 2.8A, 10.1A, 13.2A로 측정되었다. 점화봉 간격이 6mm로 고정시키고 점화봉 길이가 30cm, 500cm, 1000cm일 때 2.73A1, 0.2A, 32.6A로 측정되었다. 점화봉 간격이 8mm로 고정시키고 점화봉 길이가 30cm, 500cm, 1000cm일 때 3.13A, 9.37A, 21.4A로 측정되었다. 점화봉 간격이 10mm로 고정을 시키고 점화봉 길이가 30cm일 때는 3.4A, 14.4A, 25.6A로 측정되었다. 결론적으로 점화봉 길이가 증가 하면 전류도 증가되었다.