• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.6
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• pp.501-517
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• 2011

In general, the tunnel stability during excavation is assessed by comparing measured displacements at roof and sidewall to control criteria. The control criteria were established based on the past experience that considered ground conditions, size of the tunnel cross section, construction method, supports, etc. Therefore, a number of researches on the control criteria using the critical strain have been conducted. However, the critical strain obtained from uniaxial compression tests have drawbacks of not taking damage in rock mass due to increase of stress level and longitudinal arching into account. In this paper, damage-controlled tests simulating stress level and longitudinal arching during tunnel excavation were carried out in addition to uniaxial compression tests to investigate the critical strain characteristics of granite and gneiss that are most abundant rock types in Korean peninsula. Then, the critical strains obtained from damage-controlled tests were compared to those from uniaxial compression tests; the former showed less values than the latter. These results show that the critical strain obtained from uniaxial compression tests has to be reduced a little bit to take stress history during tunnel excavation into account. Moreover, the damage critical strain was proposed to be used for assessment of the brittle failure that usually occurs in deep tunnels.

• Journal of Broadcast Engineering
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• v.25 no.4
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• pp.609-619
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• 2020

In accordance with a demand for high quality video streaming, it needs high data rate in limited bandwidth and more traffic congestion occurs. In particular, when providing real time video service, packet loss rate and bit error probability increase significantly. To solve these problems, a raptor code, which is one of FEC(Forward Error Correction) techniques, is pervasively used in the application layers as a method for improving real-time service quality. In this paper, we propose a method of determining image transmission parameters based on various deep neural networks to increase transmission efficiency at a similar level of image quality by using raptor codes. The proposed neural network uses the packet loss rate, video encoding rate and data rate as inputs, and outputs raptor FEC parameters and packet sizes. The results of the proposed method present that the throughput is 1.2% higher than that of the existing multimedia transmission technique by optimizing the transmission efficiency at a PSNR(Peak Signal-to-Noise Ratio) level similar to that of the existing technique.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.693-697
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• 2007

The SSB modem performs the modulation process which converts the digital voltage level to the audible frequency band signal and the demodulation process which converts reversely the audible frequency signal to the digital voltage level. The modulator and the demodulator are implemented with a single DSP chip. Because of the SSB specific character, the distortion occurs when the frequency is changed. This distortion has no effect on voice communication, but it has an significant effect on data communication. In other words, it is impossible to send data stream with adjacent 2 periods. Therefore, in case of using 2-tone FSK, it is needed to send at least 3 periods to transmit 1 bit. Therefore we implemented the modem using modified phase-delay shift keying to transmit 1 tone signal for high speed transmission. In the 1200[bps] mode, it generates 0, $187{\mu}s$ delay time at 1.3kHz symbol frequency, and in the 2400[bps] mode, 0, $70{\mu}s$, $130{\mu}s$, $200{\mu}s$ delay time at 1.5kHz symbol frequency. Finally, in the maximum 3600[bps] mode, it generates 0, $100{\mu}s$, $160{\mu}s$, $250{\mu}s$ delay time at 2.0kHz symbol frequency. The measured results of the implemented SSB modem shows a good transfer functional characteristic by spectrum analyzer, almost same bandwidth in pass band and 20dB higher SNR comparing the German PACTOR and American CLOVER and in the experimental transmitting test, we verified the transmitted data is received correctly in platform.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.8 no.1
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• pp.17-29
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• 1970

To research the seeding systems and the varieties adapted to mechanization in barley and wheat culture in Korea, the studies were carried out from October, 1969 to June, 1970 at Suwon. In these studies, six kinds of seeding systems of drilling and dibbling that seems to adapted to mechanization were tested as compared with the customary seeding system, furrowing moderately or widely, using three varieties of barley, Suwon ＃18, Barsoy and Buhufng, and three varieties of wheat, Wonkwang, Yucseung ＃3 and Yeungkwang, under the two fertilizer levels of standard and double. The summarize results gained were as follows; 1. Buhung seemed to be the most suitable variety in barley as it yielded the most and matured early and grew the safest. Barsoy suffered from winter injury. 2. Yeungkwang seemed to be the most suitable variety in wheat as it yielded the most and produced the largest grain ani grew the safest, however it matured late. Wonkwang suffered heavily from lodging injury. 3. More yield were produced and there were no increase of cultural dangers except lodging in double fertilizer level. 4. Seeding system of drilling and dibbling seems to be able to put in practice safely under the double fertilizer level when lodging resistant varieties are selected. 5. Rate of yields increase in comparison with the customary seeding system of moderate furrowing were 16 percent in drilling of 20 centimeter spacing, 13 percent in wide furrowing and 12 percent in dibbling of 20 ${\times}$ 12 centimeter spacing in barley and also 9 percent in wide furrowing, 8 percent in dibbling of 20 ${\times}$ 12 centimeter spacing and 7 percent in drilling of 20 centimeter spacing in wheat. 6. The most important cause of above yields increase seems to be the increase of spike number per unit area. 7. Yields increase by drilling as compared with furrowing was not caused by higher rate of seeding. 8. The plants matured a bit earlier by drilling and dibbling. 9. Better stands of seedling were fount in dibbling due to the promotion of germination by tramping. 10. An increase of yields will be expected by decreasing the spacing in drilling and dibbling.

• Korean Journal of Plant Resources
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• v.19 no.5
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• pp.628-633
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• 2006

ITS DNA sequences from five individuals, representative of five groups designated according to the degree of leaf teeth and lobes from simple to palmate compound leaf in the Viola albida complex, established and further analysed in order to solve the taxonomic difficulty. A total 702 bp was sequenced at the 5.8S ribosomal DNA and internal transcribed spacer 1 and 2. The 5.8S coding region is 163 bp, and has no sequence variations. The ITS1 and ITS2 noncoding regions have a little bit sequence variations, and those were further analysed by the methods of the analysis of variance (ANOVA), the analysis of sequence divergence and the phylogenetic analysis. The result of ANOVA showed no significant differences among individuals investigated. The analysis of sequence divergence with Kimura 2-parameter distance revealed that in-groups showed much less than 0.05 in absolute value among individuals, while two out groups more than 0.05, V. grypoceras and V. orientalis. This result appeared that the sequence divergence among in-groups was not yet occurred in the species level but situated at somewhere below the species level. In the phylogenetic analysis, two outgroups formed the basal clades in order. Five individuals in-groups formed a clade. The clade was, however, not very robust as around 50% in bootstrap value, suggesting that this result was not meaningful in the phylogenetic point of views.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.3
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• pp.245-253
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• 2001

To investigate the effects of hydromechanical and textural characteristics of sediment deposits on the cultivation of Manila clam, Ruditapes philippinarum surface and sub-surface core sediments were collected seasonally in Gomso tidal flat. Grain size distribution were analyzed to investigate the annual variation of sediment texture. In winter unimodal distribution of grain size with the peak at $5\phi$ is dominant However, during the summer sediment texture become a little bit coarser and grain size distribution shows the peaks at $4\~5 \phi$. Optimum sediment texture for the cultivation of manila clam, R. philippinarum was found to be sandy silt in which mean Brain size was between 4 and $5 \phi$ with the sand content less than $50\%$ and clay content of $5\~10\%$. Mechanical and hydrological characteristics of sediment deposits were also studied in the laboratory and the results were applied to the numerical simulation for the behavior of surface sediment subjected to the cyclic loading from sea-water level change. Results of numerical simulation illustrate that the permeability of sediment had to be maintained in the range of $10^{-11}\sim10^{-12}m^2$ to ensure the proper sedimentological environment for the cultivation of manila clam, R. philippinarum. The deposits of virtually impermeable mud layer, with the threshold thickness of 4 cm, would be very hazardous to clam habitat.

• Journal of Korean Public Health Nursing
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• v.18 no.1
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• pp.61-73
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• 2004

This study is intended to suggest fundamental data necessary for developing MBTI program that can help improve interpersonal relation skills of nursing science major students and their cohesion. This study is pre-experimental research by one group pretest-post test design to examine the effect of MBTI(Myers and Briggs Type Indicator) basic program on the interpersonal relationship between nursing science major students and their group cohesion and the relationship between interpersonal relationship and their group cohesion. I selected 39 of sophomore students in the department nursing science of K university in I metropolitan city as test group. 35 of them joined post-test. Pretest and MBTI basic program were done before conducting MBTI program. Collected data were analyzed by SPSS window 7.5. The difference in test group before and after conducting program was examined by paired t-test. The correlation between interpersonal relationship and group cohesion was measured by using Pearson Correlation Coefficient. The findings are as follows. $\cdot$ The difference before and after conducting MBTI program by sub-factors of interpersonal relation: There was no significant difference, as the average figure of interpersonal relation in test group was 87.22 before conducting MBTI and 85.08 after conducting MBTI respectively. The average figure of sensitivity among the sub-factors of interpersonal relation was 7.71 before conducting MBTI and reduced to 7.08 after conducting MBTI and there was significant difference between before and after conducting MBTI(t=-2.484, p=.018) $\cdot$ The difference in group cohesion before and after conducting MBTI program: The average figure of group cohesion in test group was 56.68 before conducting MBTI and increased a bit to 56.80 after conducting MBTI\, but there was no significant difference between them. $\cdot$ The relationship between interpersonal relationship and group cohesion before and after conducting MBTI: As the relationship between interpersonal relationship and group cohesion before and after conducting MBTI is examined, there was positive correlation of the significance level. p<.05 before conducting MBTI(r=.320, p=.047), and of the significance level, p<.01 after conducting MBTI(r=.780, p=.000). The investigation on the relation between sub-factors of group cohesion and of interpersonal relation before conducting MBTI basic program revealed that there was positive correlation between openness, reliability, friendliness and satisfaction, and group intervention, between receptivity among group members and reliability, and between group atmosphere and satisfaction. The investigation on the relation between sub-factors of group cohesion and of interpersonal relation after conducting MBTI basic program revealed that there was positive correlation between openness, communication, understanding, friendliness and satisfaction. and group intervention. There was positive correlation between receptivity among group members and openness, communication, understanding, friendliness and satisfaction. There was positive correlation between openness, communication, friendliness and satisfaction, and group atmosphere. Based on the above findings, I realize that MBTI basic program is essential to the improvement of group cohesion. In addition, it is shown that the sub-factors of interpersonal relation such as openness, communication, friendliness, satisfaction, and understanding, and the sub-factors such as group intervention and receptivity among group members are major factors to improve interpersonal relationship and group cohesion. So, the future MBTI program should include sub-programs that deal with the above factors to improve interpersonal relationship and group cohesion.

• Journal of Broadcast Engineering
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• v.15 no.1
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• pp.63-75
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• 2010

In this paper, the equalizer techniques that is able to adopt the digital on-channel repeater for 8VSB-based DTV system has been analyzed and we propose an effective equalizer structure which can reduce the error propagation phenomenon by the feedback signal and improve the receiver performance at the same time. In order to confirm the effective cancellation of the feedback signal, the multi-level Correlation LMS scheme is proposed through the analysis of conventional basic LMS based DFE and Correlation LMS algorithm and as compared with the conventional method, we can confirm the reduction of error propagation. When performing the computer simulation, as the Brazil channel model which is very popular for DTV broadcasting system is adopted, the result is drawn by comparing and analysing the equalizer algorithm. We have examine the symbol error rate which is in the range of 15~25dB of operation receipt SNR and MSE(Mean Square Error) in the DTV broadcasting system. As a result of comparing with the existing method, the signal-noise ratio which is necessary for maintain the bit error correction ability that the means of proposal is same is reduced by about 2~5dB, and in the rate of convergence through the MSE, we found the reduction of needed time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.10
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• pp.1852-1857
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• 2007

The SSB modem performs the modulation process which converts the digital voltage level to the audible frequency band signal and the demodulation process which converts reversely the audible frequency signal to the digital voltage level. The modulator and the demodulator are implemented with a single DSP chip. Because of the SSB specific character, the distortion occurs when the frequency is changed. This distortion has no effect on voice communication but it has an significant effect on data communication. In other words, it is impossible to send data stream with adjacent 2 periods. Therefore, in case of using 2-tone FSK, it is needed to send at least 3 periods to transmit 1 bit. Therefore we implemented the modem using modified phase-delay shift keying to transmit 1 tone signal for high speed transmission. In the 1200[bps] mode, it generates 0, $187{\mu}s$, delay time at 1.3kHz symbol frequency, and in the 2400[bps] mode, 0, $70{\mu}s\;130{\mu}s\;200{\mu}s$, delay time at 1.5kHz symbol frequency. Finally, in the maximum 3600[bps] mode, it generates 0, $100{\mu}s\;160{\mu}s\;250{\mu}s$ 2.0kHz symbol frequency. The measured results of the implemented SSB modem shows a good transfer functional characteristic by spectrum analyzer, almost same bandwidth in pass band and 20dB higher SNR comparing the emu FACTOR and American CLOVER and in the experimental transmitting test, we verified the transmitted data is received correctly in platform.

• The Korean Journal of Rehabilitation Nursing
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• v.6 no.1
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• pp.26-39
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• 2003

The elderly can experience a lot of stressful events and the stress acts as a various fluent that affects a well-being level, the self-contentment of lives, and the achievements by themselves. Also, the elderly are different from the young in many unexpressed stress and have diverse copings for perceived stress. Moreover, they mainly seem to use a problem-focused coping and an emotion-focused coping. To use whatever copings is to improve the quality of life in the old period and very important fact to achieve their ends. The purpose of this study was to investigate the relationship between Perceived Stress and the Ways of Coping in the Elderly and to gain the baseline data for development of nursing intervention program for improve to the quality of life in the elderly. The design of this study was a correlational study. The subjects of this study consisted of 230 of the elderly living in Pusan. The data was collected from 1st July. to 1st September, 2002. The instruments used for this study were 'Perceived Stress Scale(20items, 5point. scale)' developed by Kang In(1990) and translated by Lee young-ja(1999), and its reliability is Cronbach's ${\alpha}=.89$. 'Coping Scale(30items, 4point. scale, 14 items about a problem-focused coping, 16 items about an emotion-focused coping, 4 points scale) developed by Lazarus & Folkman(1984) and translated by Yang Young-hee(1998). The reliability of this study is Cronbach's ${\alpha}=.90$. The data was analyzed by the SPSS WIN 10.0 program using frequency, percentage, mean, standard deviation, t-test, ANOVA & Scheffe test and Pearson's correlation coefficient. The results of this study were as follows; 1. The mean score of perceived stress was $31.75{\pm}10.23$(Min 20, Max 100), which the item mean score was $1.59{\pm}.51$(Min 1, Max 5). 2. The number of subjects in a problem-focused coping was 72(31.3%), the number of subjects in an emotion-focused coping was 158(68.7%) 3. There were statistically significant positive correlation between perceived stress and problem-focused coping method and the more emotion-focoused coping method.(r=.180, r= .209, P< .05). It means the more stress, the more problem-focused coping method and the more emotion-focused coping method. 4. There was significant difference the score of perceived stress according to sex (F=-5.057, P=.000)marital status, (F=-2.909, P=.004), economic level, (F=10.243, P=.000), paticipated meeting, (F=9.346, P=.000), perceived health status(F=5.117, P=.007). 5. There was significant difference the score of problem-focused coping method according to age(F=14.200, P=.000), marital status (F=2.432, P=.0160), economic level (F=14.410, P=.000), monthly income, (F=8.300. P=.000), income resource (F=10.235, P=.000), educational level (F=15.222, P=.000), occupation (F=1.544, P=.041), paticipated meeting (F=4.936, P=.008), perceived health status(F=5.655, P=.004). And there was significant difference the score of emotion-focused coping method according to monthly income(F=4.781, P=.009), income resource(F=2.930, P=.035), educational level(F=6.101, P=.003), religionF=2.698, P=.032), paticipated meetings(F=7.285, P=.001). As a result of the study, the elderly had a bit less stress and the two-thirds of the elderly used the emotion-focused coping. Thus, the more perceived stress, the more problem-focused coping method and the more emotion-focused coping method. Accordingly, to improve the quality of life of the elderly, there needs and applies a nursing intervention program that relieves the stress and use effective coping method.