• Journal of Korean Society of Steel Construction
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• v.9 no.4 s.33
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• pp.543-555
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• 1997

Generally, in a steel-concrete composite gilder, the shear connector which was constructed between concrete deck and steel girder should have enough stiffness to behave as one body, because the conformity between plate and concrete deck is influences by the stiffness and spacing of the shear connectors. If the stiffness of shear connectors are insufficient, slip would happen at the contact surface. Partial interaction is the case that takes account of slips. In this paper, an easy method is presented to evaluate the stiffness or spacing of the shear connector according to the degree of imperfection without difficult calculations for a composite gilder with partial interaction. Also, the horizontal shearing force applied to the shear connector and the longitudinal axial force, which is occurs at contact surface between concrete deck and steel girder, have been presented in a simple influence line that is various to the parameters of sectional properties, degree of imperfection and applied load points. Furthermore, through the case study, it determined the relationships between the degree of imperfection and the follows 1) spring constants 2) axial force and horizontal shearing force 3) stress and neutral axis by using the partial differential equation based on Newmark's Partial Interaction Theory.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.233-236
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• 2005

본 논문에서는 중첩되는 두 개 이상의 PAN의 무선영역이 간섭을 일으키는 경우와 다수의 무선기기가 동시에 접속하는 경우에 대비하여 간섭마진 정보를 이용한 가변 전송율을 갖는 UWB 통신 시스템을 제안한다. 또한, 가변 전송율 UWB 통신 시스템을 불완전 다중접속 간섭 환경에서 고정 전송율을 갖는 UWB 통신 시스템과의 성능을 비교 분석하고 전송효율을 평가하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.241-245
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• 2005

본 논문에서는 가변 전송율을 갖는 UWB 통신 시스템을 제안하고 다수의 무선 기기가 유동적으로 이동하는 파코넷 환경에서 다중접속 간섭 및 전송율에 따른 시스템 성능을 분석하였다. 또한, 전송품질을 향상시키기 위하여 Truncated Type-II Hyabrid ARQ 기법을 적용하여 불완전 채널 환경에서의 시스템 성능을 평가하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.5
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• pp.589-595
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• 2019

Recently, the mobile social networks, which consider both social relationship between users and mobile communication networks, have been received great attention. In this paper, we consider the trust degree of node as the social relationship for the cooperative communication networks. In contrast to the existing works that consider the case of the perfect trust degree information, for the case that transmitter has an imperfect trust degree information, we propose an imperfect trust degree based cooperative communication technique that maximizes a throughput. We first model the imperfect trust degree information as a probability distribution and derive the outage probability using the probability distribution. Then, we propose the transmission scheme that maximizes the throughput, which consider both outage probability and transmission rate. The simulation results show that the proposed cooperative transmission scheme outperforms the conventional scheme in terms of the throughput.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.247-249
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• 2011

기존의 OFDMA 시스템에서의 자원할당 기술은 주로 완벽한 채널정보에 기반하여 송신 전력, 부반송파를 할당하였다. 하지만 실제 시스템에서는 사용자의 움직임이나 채널 피드백 지연에 의해 완전한 채널정보를 얻을 수 없다. 본 논문에서는 불완전한 채널 정보를 갖는 OFDMA 중계 네트워크를 위한 자원 할당 기법을 제안한다. 불완전한 채널 정보를 갖는 환경에서는 패킷 오류가 발생할 확률이 높기 때문에 이를 예측하여 적응적 데이터 전송률을 할당하는 기법이 필요하다. 제안된 알고리즘은 채널 정보를 예측하여 데이터 전송률, 그리고 부반송파 할당을 통해 유효처리율을 최대화시킨다. 모의 실험 결과 제안된 알고리즘은 채널정보를 예측하지 않는 단순한 알고리즘과 비교하여 더 높은 유효처리율을 갖음을 확인하였다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.5
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• pp.502-511
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• 1994

Investigated were the relationships between plumule elongation characteristics and seedling emergence of 98 varieties including native, improved and red rice varieties of Korea, and varieties from U.S.A., Italy, Japan, etc. under proper and excess soil moisture regimes. Under excess soil moisture condition the seedling emergence and establishment rates were much lower in most of the varieties and the seedling emergence rates were delayed substantially in all varieties employed. The seedling emergence rates were lowest in dwarf and some semi-dwarf varieties showing poor plumule elongation under proper soil moisture condition. The seedling emergence and establishment rates were significantly correlated with the length of mesocotyl, coleoptile and incomplete leaf under both soil moisture regimes, and with the lower first and second internode length under excess soil moisture condition. Average emergence duration showed significant negative correlation with the length of mesocotyl, coleoptile and incomplete leaf under both soil moisture regimes and significant positive correlations with the first and third lower internode length. Based on the standardized partial regression analysis only the variations of mesocotyl and coleoptile length contributed significantly to the varietal difference in seedling establishment rate, and so did the variations of mesocotyl and incomplete leaf length to the varietal differences in emergence speed. In conclusion varieties with greater elongation characteristics of mesocotyl, coleoptile and incomplete leaf are desirable for higher and speedy seedling establishment in dry-direct seeding.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.7
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• pp.1473-1478
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• 2005

In this paper, we proposed UWB system with variable rate in piconet environment that several wireless devices moves as variable. And, we analyzed the performance of UWB system according to multiple access interference and transmission rate. Also, we have evaluated the performance of m system with Truncated Type-II Hybrid ARQ scheme fer achieving high qualify data transmission.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.59-68
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• 1995

Investigated were the relationships between plumule elongation characteristics and seedling emergence of 46 varieties including native, improved and red rice varieties of Korea, and varieties from U.S.A., Italy, India, Japan under 1, 3, and 5cm deep sowing with irrigated and non-irrigated condition. Experiments were carried out in paddy field of sandy loam. There was heavy shower of 19.2mm on the next day of seeding and thereafter, clear and dry weather continued during the experiment period. Soil temperature averaged over 30 days after seeding was $16.4^{\circ}C$ at 3cm depth. Soil hardness increased linearly up to 2.5kg /$cm^2$ on the 14th day after seeding, on which date irrigated plot was irrigated through furrow, and up to 4kg / $cm^2$ on the 28th day in non-irrigated plot. Soil hardness dropped near to 0kg /$cm^2$ after irrigation and developed up to 2.5kg /$cm^2$ again by 28 days after seeding. Seedling emergence was higher in irrigated plots than non-irrigated plots at all seeding depths. Korean improved varieties were substantially lower in seedling emergence under non-irrigated condition of 1 cm deep sowing than those under irrigated condition. This poor seedling emergence resulted mainly from delayed emergence by exposing them to greater soil strength. Percent seedling emergence under irrigated and non-irrigated condition showed signifi-cant correlations at 3 and 5 cm deep sowing. Korean improved varieties belonged to the group of poor seedling emergence, and I taliconaverneco, Chinsura Boro and Weld Pally to best group under both irrigation conditions at 3 and 5cm deep sowing. Seedling emergence showed highly signifi-cant positive correlation with the plumule length of mesocotyl ＋ 1st internode ＋ incomplete leaf and of mesocotyl＋coleoptile. Among the characters constituting plumule length, incomplete leaf length showed greatest positive correlation followed by coleoptile and mesocotyl under irrigated condition at 3 and 5 cm deep sowing, and highest correlation with mesocotyllength followed by first internode and incomplete leaf under non-irrigated condition. Days to 50% seedling emergence at 1 cm deep sowing with irrigation showed great varietal variation of 10 to 30 days, and showed high significant negative correlations with percent seedling emergence under both irrigation conditions except for 1 cm deep sowing with irrigation, Days to seedling emergence revealed sig-nificant negative correlations with plumule characters except 2nd internode, showing highest cor-relation with incomplete leaf length.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.2A
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• pp.99-108
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• 2002

In this paper, we discuss the effect of imperfect knowledge of the transmission channel on the M-QAM SER performance of space-time block codes. Because the channel knowledge is used for decoding of space-time block codes, the imperfect channel knowledge can degrade the performance of space-time block codes. In this paper, the channel mismatch error is modeled as errors in the estimation of the channel due to noise and errors due to the variation of the channel. We derive the analytic expression for the symbol error rate (SER) as a function of the average signal to interference ratio (SIR) per channel including the terms of channel mismatch errors. Simulation results show that the acceptable levels of channel estimation error is 10$\^$-3/ and that of channel variation is f$\_$d/T$\_$B/=0.001 at SNR=20dB in space-time block codes.

• The Korean Journal of Applied Statistics
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• v.32 no.1
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• pp.29-40
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• 2019

Categorical data with non-responses are frequently observed in election poll surveys, and can be represented by incomplete contingency tables. To estimate supporting rates of candidates, the identification of the missing mechanism should be pre-determined because the estimates of non-responses can be changed depending on the assumed missing mechanism. However, it has been shown that it is not possible to identify the missing mechanism when using observed data. To overcome this problem, sensitivity analysis has been suggested. The previously proposed sensitivity analysis can be applicable only to two-way incomplete contingency tables with binary variables. The previous sensitivity analysis is inappropriate to use since more than two of the factors such as region, gender, and age are usually considered in election poll surveys. In this paper, sensitivity analysis suitable to an multi-dimensional incomplete contingency table is devised, and also applied to the 19th Korean presidential election poll survey data. As a result, the intervals of estimates from the sensitivity analysis include actual results as well as estimates from various missing mechanisms. In addition, the properties of the missing mechanism that produce estimates nearest to actual election results are investigated.