• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.1053-1060
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• 2003

The temperature variation of the concrete pavement in the early age significantly affects the initiation and propagation of its early age cracks. This implies that the measurement and analysis of early age temperature trend are necessary to examine the causes of early age cracks in the concrete pavement. In this study, it is investigated how the early age temperature trend in the concrete pavement affects the random crack initiation and behaviors of saw-cut joints using the actual construction site which is located at the KHC test road. During 72 hours after placing the concrete pavement, the ambient air temperature and temperatures at the top, middle, and bottom in the concrete pavement were measured and the random crack initiation in concrete slabs and early age behaviors in the joints were surveyed. The investigation results indicate that the first random crack was initiated at one of the slabs placed in the early morning which have higher temperature changes during early 72 hours. In addition, the joints that were saw-cut in the morning were cracked more rapidly than those saw-cut in the afternoon.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.1
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• pp.67-74
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• 2017

This study proposes a novel random pulse-width modulation (PWM) technique with a constant switching frequency utilizing a random offset voltage. The proposed PWM technique spreads switching harmonics by varying the position of an active voltage vector without a switching frequency variation. The implementation of the proposed PWM technique is simple because it does not require additional hardware and complex algorithm. The proposed random PWM technique is compared with the conventional PWM technique on the factors of harmonic spectrum, total harmonic distortion, and harmonic spread factor to confirm the harmonic spread effect. The validity of the proposed method is verified by simulations and experiments on a three-phase inverter drive system.

• Journal of Life Science
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• v.14 no.1
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• pp.115-120
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• 2004

Lepista nuda is a world-wide species which has and international reputation as a excellent edible species. In this study, we investigated the genetic variation and taxonomic relationship of L. nuda and other five Tricholomataceae species were analyzed by random amplied polymorphic DNA (RAPD). 15 kinds of random primers were used. The distance matrix was calculated using UPGMA and phyolgenetic relationship were inferred by neighnor-joining (NJ) method. Various bands of 100bp∼1600bp were observed in electrophoretic patterns of RAPD. Nei's genetic distance was calculated using a total of 228 DNA bands identified, and phylogenetic tree was made. The Nei's genetic variations of L. nuda, Lepista surdida, Collybia peronata, Collybia confluens, Lyophyllum cinerascens, Laccara laccata were 0∼21.3%, 21.2∼28.0%, 15.4∼23.0%, 14∼21.8%, 16.5∼34.6%, and 12.4∼27.4%, respectively The consistency index, the retention index and homoplasy index were 0.5217, 0.5769 and 0.5156, respectively. Also, two groups could be made by NJ tree. The genetic distance between L. nuda and C. confluens was closer than that between L. nuda and L. sordida.

• Proceedings of the KIEE Conference
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• 1986.07a
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• pp.305-310
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• 1986

• Journal of Life Science
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• v.18 no.2
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• pp.175-179
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• 2008

Cornus controversa is a long-lived woody species mostly distributed in East Asia. Random amplified polymorphic DNA (RAPD) markers were used to investigate the genetic diversity and population structure of Korean populations of this species. A high level of genetic variation was found in seven populations of C. controversa. The mean genetic diversity (H) was 0.222 across populations, varying from 0.200 to 0.238. Eighty of the 93 loci (86.0%) showed detectable polymorphism in at least one population. Total genetic diversity values ($H_T$) varied between 0.192 and 0.231, giving an average overall polymorphic loci of 0.212. The interlocus variation of genetic diversity within populations ($H_S$) was high (0.167). Mean of genetic diversity in C. controversa was higher than average values for species with similar life history traits. The sexual reproduction, perennial habitat, and longevity are proposed as possible factors contributing to high genetic diversity. On a per locus basis, the proportion of total genetic variation due to differences among populations ($G_{ST}$) ranged from 0.169 to 0.278 with a mean of 0.216, indicating that about 21.6% of the total genetic variation was among populations. An indirect estimate of the number of migrants per generation (Nm=1.893) indicated that gene flow was extensive among Korean populations of C. controversa.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.755-759
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• 2012

In this paper, it is about random number generator, which is based on hardware is utilized in medical science and game area. The Intel presents guideline of security level about hardware based true random number generator. At hardware based random number generator, the various test items, that are included in test suits as NIST statistical test, FIPS140-1, is applied. In this paper, it experiments about degree extent of randomness variation from filter scheme effects, which is applied in output stream of hardware noise source.

• Research in Mathematical Education
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• v.6 no.1
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• pp.97-106
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• 2002

Educators have found that the concept of randomness is often misunderstood by students. Chance recently pointed out that students should be introduced to the concept of randomness through the use of simulations. In this article, we studied various aspects of the probability distribution off linear random path in a circle and introduce some related simulations to guide student exploration and discovery. Consider a random line segment that crosses a circle with a certain radius. Perhaps it can be considered to be a path that an airplane shows up and flies into a random direction in a monitor. What is the expected amount of flying distance through the monitor, and the expected variation\ulcorner Are we monitoring what we see scientifically\ulcorner This article studies the probability distribution and some related aspects of a linear random path within a circular monitor. Some simulative activity is also introduced which can be used in a statistics or probability classes.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.212-217
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• 2007

As a preliminary study for the development of electrical stimulation strategy of artificial retina, we set up a method fur the reconstruction of input intensity variation from retinal ganglion cell(RGC) responses. In order to estimate light intensity variation, we used an optimal linear filter trained from given stimulus intensity variation and multiple single unit spike trains from RGCs. By applying ON/OFF stimulation(ON duration: 2 sec, OFF duration: 5 sec) repetitively, we identified three functional types of ganglion cells according to when they respond to the ON/OFF stimulus actively: ON cell, OFF cell, and ON-OFF cell. Experiments were also performed using a Gaussian random stimulus and a binary random stimulus. The input intensity was updated once every 90 msec(i. e. 11 Hz) to present the stimulus. The result of reconstructing 11 Hz Gaussian and binary random stimulus was not satisfactory and showed low correlation between the original and reconstructed stimulus. In the case of ON/OFF stimulus in which temporal variation is slow, successful reconstruction was achieved and the correlation coefficient was as high as 0.8.

• Design & Manufacturing
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• v.14 no.1
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• pp.63-68
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• 2020

Ultra-high brightness and thin displays need to optical micro-patterns which can uniformly diffuse the lights and low loss. The micro random patterns have characteristics to rise the optical efficiency such as light extraction, uniform diffusion. For this reason, various fabrication processes are studied for random patterns. In this study, the micro random patterns were machined by diamond turning which used a controlled cutting tool path with random cutting depth. The machined patterns had random shape and directionality along the circumferential direction. The average width and length of machined random pattern according to rotation radius were 40.13㎛~55.51㎛ and 37.25㎛~59.49㎛, and these results were compared with the designed result. Also, the machining error according to rotation radius in diamond turning using randomly controlled cutting depth was discussed.

• Journal of Life Science
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• v.22 no.11
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• pp.1470-1476
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• 2012

A genetic variation of Lepista nuda and two genus Lepista species (L. irina and L. sordida) were analyzed by random amplified polymorphic DNA (RAPD) and internal transcribed spacer (ITS) sequence analysis. In the resulting RAPD analysis, 22 out of 40 random primers amplified polymorphic RAPD fragment patterns, the amplified bands were 355, and DNA fragment sizes were 200-400bp. Intraspecific genetic dissimilarity of the 10 L. nuda strains were calculated to range from 0% to 21.60%, L. sordida from 16.93% to 24.82%, L. irina were 20.62% to 25.54%, and intraspecific genetic dissimilarity of L. sordida and L. irina was 23.49%. The 673 base pairs were sequenced during the analysis of the ITS I and II region; six L. nuda strains intraspecific genetic dissimilarities ranged from 1.58% to 11.47%, L. nuda and L. sordida from 3.83% to 12.88%, L. nuda and L. irina from 7.11% to 15.61%, and intra-specific genetic variation between L. sordida and L. irina was 4.79%. The findings showed that RAPD and ITS sequencing could be used for developing molecular genetic markers and screening of unidentified genus Lepista species.