• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.121-127
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• 2013

Memory devices including SRAM and DRAM are very susceptible to high energy radiation particles in the space. Abnormal operation of the devices is caused by SEE or TID. This paper presents a method to estimate proton SEU cross section representing the susceptibility of the latch circuit that the unit cell of the SRAM and proposes a new latch circuit to mitigate the SEU. 50b shift register was fabricated by using the conventional latch and the proposed latch in $0.35{\mu}m$ process. Irradiation experiment was conducted at KIRAMS by using 43MeV proton beam. It was found that the proposed latch-shift register is not affected by the radiation environment compared to the conventional latch-shift register.

• Journal of Space Technology and Applications
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• v.3 no.4
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• pp.333-341
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• 2023

This study aims to develop technology for testing and verifying the space radiation environment of miniature space components using the facilities of the domestic 100 MeV proton accelerator and the Space Component Test Facility at the Space Testing Center. As advancements in space development progress, high-performance satellites increasingly rely on densely integrated circuits, particularly in core components components like memory. The application of semiconductor components in essential devices such as solar panels, optical sensors, and opto-electronics is also on the rise. To apply these technologies in space, it is imperative to undergo space environment testing, with the most critical aspect being the evaluation and testing of space components in high-energy radiation environments. Therefore, the Space Testing Center at the Korea testing laboratory has developed a radiation testing device for memory components and conducted radiation impact assessment tests using it. The investigation was carried out using 100 MeV protons at a low flux level achievable at the Gyeongju Proton Accelerator. Through these tests, single event upsets observed in memory semiconductor components were confirmed.

• Journal of Semiconductor Engineering
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• v.1 no.3
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• pp.81-87
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• 2020

An instrumentation amplifier (IA) and an analog-to-digital converter (ADC) are essential circuit blocks for accurate and robust sensor readout systems. This paper introduces recent advances in radiation-hardening by design (RHBD) techniques applied for the sensor readout integrated circuits (IC), e.g., the three-op-amp IA and the successive-approximation register (SAR) ADC, operating against total ionizing dose (TID) and singe event effect (SEE) in harsh radiation environments. The radiation-hardened IA utilized TID monitoring and adaptive reference control to compensate for transistor parameter variations due to radiation effects. The radiation-hardened SAR ADC adopts delay-based double-feedback flip-flops to prevent soft errors which flips the data bits. Radiation-hardened IA and ADC were verified through compact model simulation, and fabricated CMOS chips were measured in radiation facilities to confirm their radiation tolerance.

• Journal of Astronomy and Space Sciences
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• v.22 no.4
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• pp.537-558
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• 2005

This paper addresses the results of HAUSAT-2 radiation environment and effect analyses, including TID and SEE analyses. Trapped proton and electron, solar proton, galactic cosmic ray models were considered for HAUSAT-2 TID radiation environment analysis. TID was analyzed through total dose-depth curve and the radiation tolerance of TID for HAUSAT-2 components was verified by using DMBP method and sectoring analysis. HAUSAT-2 LET spectrum for heavy ion and proton were also analyzed for SEE investigation. SEE(SEU, SEL) analyses were accomplished for MPC860T2B microprocessor and K6X8008T2B memory. It was estimated that several SEUs may occur without SEL during the HAUSAT-2 mission life(2 years). Software Hamming Code EDAC has been implemented to detect and correct the SEU. In this study, all radiation analyses were conducted by using SPENVIS software.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.2
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• pp.56-67
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• 2006

The reliability and failure mode effect analysis are effective means to achieve efficient and cost-reduction design for satellite development. The failure rate of COTS (Commercial-Off-The-Shelf) parts required for reliability analysis is not usually provided from the manufacturer. Space environment factors based on empirical data obtained from MIL-HDBK-217F can be applicable to the reliability calculation. As a radiation environment factor, the occurrence rate of SEL (Single Event Latch-up) is additionally incorporated for the failure rate prediction. In this paper, the statistical reliability analysis method for low-cost small satellite using COTS parts is suggested. This statistical reliability analysis was applied to HAUSAT-2 small satellite whose electronic boxes are consisted of many COTS parts to calculate the system reliability at the end of design mission life.

• Korean Journal of Microbiology
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• v.17 no.3
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• pp.137-151
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• 1979

Germinating conidia of Aspergillus nidulans diploid heterozygous for color and other genetic markers were used to direct and distinguish genetic events such as mutation, mitotic crossingover and nondisjunction in a single test after treatment with N-methyl-N'-nitro-N-nitrosoguanidine (NG), mitomycin C(MC), and chloral hydrate(CH). The following results were obtained : 1. NG reduced the survival of conidia and increased the frequencies of miototic segregants about sevenfoli over the control ; among the mitotic segregants the predominant genetic event was mitotic crossingover. NG also produced many abnormal colonies, which appeared to be of the types caused by induced semidominant lethals or chromosomal aberrations, and the aneuploid types found spontaneously. 2. After treatment with MC the survival of conidia was reduced but few abnormal colonies were produced. The frequencies of miotic segregants were increased about threefold over the control ; in the mitotic segeregants the induced genetic event was mitotic crossingover. 3. CH gave no apparent effect on the survival of conidia and the frequencies of mitotic segregants. However, CH generated abnormal colonies, very greatly, which turned out to be of the aneuploid types. This result suggests that CH interferes with the normal distribution of chromosomes in mitosis.

• The Journal of Korean Institute of Next Generation Computing
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• v.15 no.1
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• pp.86-98
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• 2019

Recently, the trend of building container-based PaaS (Platform-as-a-Service) is expanding. Container-based platform technology has been a core technology for realizing a PaaS. Containers have lower operating overhead than virtual machines, so hundreds or thousands of containers can be run on a single physical machine. However, recording and monitoring the storage logs for a large number of containers running in cloud computing environment occurs significant overhead. This work has identified two problems that occur when detecting a file system change event of a container running in a cloud computing environment. This work also proposes a system for container file system event detection in the environment by solving the problem. In the performance evaluation, this work performed three experiments on the performance of the proposed system. It has been experimentally proved that the proposed monitoring system has only a very small effect on the CPU, memory read and write, and disk read and write speeds of the container.

• The Korea Journal of Herbology
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• v.36 no.5
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• pp.69-79
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• 2021

Objectives : In clinical practice, there are many cases of co-administration of herbal medicine and synthetic drugs. This study tried to identify whether the combined administration of herbal medicine and synthetic drugs including amoxicillin increases Helcicobacter pylori eradication rate compared to the single administration of synthetic drugs or the combined administration of synthetic drugs and placebo herbal medicine through systematic review. Methods : Relevant randomized controlled trials were searched in PubMED database. The risk of biases was assessed through the Cochrane Risk of Bias criteria. Three reviewers were extracted the characteristics and outcomes of each study. Meta-analysis of eradication rate and adverse event was conducted. Results : Four RCTs were selected. In meta-analysis, the combination of herbal medicine and synthetic drugs showed eradication effect, but it was not statistically significant (Odds Ratio [OR] 0.46; 95% confidence interval [CI] 0.17 to 1.24; p=0.13; I²=56%) than administration of synthetic medicine alone. Combination of herbal medicine and synthetic medicine did not increased the incidence of adverse event(OR 1.07; 95% CI 0.72 to 1.59; p=0.68, I²=0%) compared to single administration of synthetic medicine. Conclusion : Although no significant difference was observed between the two groups in the eradication rate and the incidence rate of adverse events, it was difficult to draw a clear conclusion due to the heterogeneity between studies and the low quality of reporting. A number of studies that have overcome these limitations in the future will lead to definite conclusions.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.44.1-44.1
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• 2017

The single lens event OGLE-2015-BLG-1482 has been simultaneously observed from two ground-based surveys and from Spitzer. The Spitzer data exhibit finite-source effects due to the passage of the lens close to or directly over the surface of the source star as seen from Spitzer. Thanks to measurements of the microns parallax and the finite-source effect, we find that the lens of OGLE-2015-BLG-1482 is a very low-mass star with the mass $0.10{\pm}0.02M{\odot}$ or a brown dwarf with the mass $55{\pm}9MJ$, which are respectively located at $DLS=0.80{\pm}0.19kpc$ and $DLS=0.54{\pm}0.08kpc$, and thus it is the first isolated low-mass microlens that has been located in the Galactic bulge. The degeneracy between the two solutions is severe. The fundamental reason for the degeneracy is that the finite-source effect is seen only in a single data point from Spitzer and this single data point gives rise to two ${\rho}$ solutions.

• Journal of the Korea Society of Computer and Information
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• v.26 no.8
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• pp.187-196
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• 2021

This study uses data from the 11th year(2016) to the 15th year(2020) of the Korea Welfare Panel(KOWEPS) for the five years that the survey was completed to predict the life satisfaction of each individual by generation, centered on single-person households. This is a longitudinal analysis using a latent growth model. The generational division was based on the turning point of a major event experienced by the cohort that brought about a decisive change in the socialization process, historical event, and technological development as factors. The analysis data used in this study were of 27,447 persons in the 15th year of the Korea Welfare Panel(2020), 2,778 persons who were single-person households even in the first year from the last 5 years, and 1,448 persons who were single-person households continuously for 5 years. Excluding those born in 1922 to 1944(843 persons), 605 persons born between 1945 and 1996 were included. As a result of the study, Generation Y(millennials) than Generation X(new generation) and Generation X generation than Baby Boomers showed higher overall life satisfaction. Since overall life satisfaction by generation does not have an effect on the rate of change, it was found that this difference remains the same for all generations.