• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 2001.06a
• /
• pp.83-89
• /
• 2001

Recent advances in the structural and molecular biology uncovered that a set of translation factors resembles a tRNA shape and, in one case, even mimics a tRNA function for deciphering the genetic ：ode. Nature must have evolved this 'art' of molecular mimicry between protein and ribonucleic acid using different protein architectures to fulfill the requirement of a ribosome 'machine'. Termination of protein synthesis takes place on the ribosomes as a response to a stop, rather than a sense, codon in the 'decoding' site (A site). Translation termination requires two classes of polypeptide release factors (RFs)： a class-I factor, codon-specific RFs (RFI and RF2 in prokaryotes; eRFI in eukaryotes), and a class-IT factor, non-specific RFs (RF3 in prokaryotes; eRF3 in eukaryotes) that bind guanine nucleotides and stimulate class-I RF activity. The underlying mechanism for translation termination represents a long-standing coding problem of considerable interest since it entails protein-RNA recognition instead of the well-understood codon-anticodon pairing during the mRNA-tRNA interaction. Molecular mimicry between protein and nucleic acid is a novel concept in biology, proposed in 1995 from three crystallographic discoveries, one, on protein-RNA mimicry, and the other two, on protein-DNA mimicry. Nyborg, Clark and colleagues have first described this concept when they solved the crystal structure of elongation factor EF- Tu：GTP：aminoacyl-tRNA ternary complex and found its overall structural similarity with another elongation factor EF-G including the resemblance of part of EF-G to the anticodon stem of tRNA (Nissen et al. 1995). Protein mimicry of DNA has been shown in the crystal structure of the uracil-DNA glycosylase-uracil glycosylase inhibitor protein complex (Mol et al. 1995; Savva and Pear 1995) as well as in the NMR structure of transcription factor TBP-TA $F_{II}$ 230 complex (Liu et al. 1998). Consistent with this discovery, functional mimicry of a major autoantigenic epitope of the human insulin receptor by RNA has been suggested (Doudna et al. 1995) but its nature of mimic is. still largely unknown. The milestone of functional mimicry between protein and nucleic acid has been achieved by the discovery of 'peptide anticodon' that deciphers stop codons in mRNA (Ito et al. 2000). It is surprising that it took 4 decades since the discovery of the genetic code to figure out the basic mechanisms behind the deciphering of its 64 codons.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.57 no.5
• /
• pp.51-60
• /
• 2015

In Korea, 69.4 % of duck farms had utilized conventional plastic greenhouses. In this facilities, there are difficulties in controlling indoor environments for raising duck. High rearing density in duct farms also made the environmental control difficult resulting in getting more stressed making their immune system weaker. Therefore, a facility is needed to having structurally enough solidity and high efficiency on the environmental control. So, new design plans of duck house have recently been conducted by National Institute of Animal Science in Korea. As a study in advance to establish standard, computational fluid dynamics (CFD) was used to estimate the aerodynamic problems according to the designs by means of overall and regional ventilation efficiencies quantitatively and qualitatively. Tracer gas decay (TGD) method was used to calculate ventilation rate according to the structural characteristics of duck houses including installation of indoor circulation fan. The results showed that natural ventilation rate was averagely 164 % higher than typically designed ventilation rate, 1 AER ($min^{-1}$). Meanwhile, mechanically ventilated duck houses made 81.2 % of summer ventilation rate requirement. Therefore, it is urgent to develop a new duck house considering more structural safety as well as higher efficiency of environmental control.

• Journal of Korean Society of Steel Construction
• /
• v.26 no.4
• /
• pp.263-275
• /
• 2014

In this study, connection of steel reinforced concrete(SRC) column and composite beam which consists of H-section and U-section members were tested under cyclic loading. An essential point of the composite beam is the structural performance of welded joint between the H-section and the U-section members. To improve the structural performance of joint of two beam members, vertical stiffeners, trapezoidal stiffeners, and top bars were used. Five full-scaled specimens were designed to study the effect of a number of parameters on cyclic performance of connections such as H-section beam size($H-500{\times}200{\times}10{\times}16$, $H-600{\times}200{\times}11{\times}17$), the presence of stiffeners and top bars, and the presence of no weld access hole(WAH) method. Based on the test results, deformation capacity of the specimens with H-500 series beam and H-600 series beam were 4% and 3% rotation angle, which is the requirement for the Special Moment Frame and Intermediate Moment Frame(IMF), respectively. Test result showed that deformation capacity of connection with stiffeners and top bars is greater than that of connection without stiffeners and top bars. Finally, energy dissipation capacity and strain profile of specimens were summarized.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.15 no.3
• /
• pp.125-133
• /
• 2011

The requirement for durability of concrete bridge deck is increasing as the deterioration for the concrete bridge deck exposed to severe environment has been increased. For this reason, the concern about high-durable concrete is being high. Recently, a metakaolin is highly spotlighted as new admixture because its strength and durability are equivalent to silica fume. On the other hands, there are few researches for the metakaolin concrete bridge deck in domestic. So many various long-term data on the mechanical property and durability is needed to apply metakaolin concrete at the concrete bridge deck construction field. This study is aim to evaluate the long-term mechanical properties and durability of metakaolin concrete bridge deck with curing age. Mechanical properties are estimated by the compressive and flexural strength, and the drying shrinkage, the chloride resistance, the scaling, and freezing and thawing characteristics are compared with curing age. According to the results, when the metakaolin concrete is used, the development of compressive and flexural strength proceed in both the early and old ages. It is also improved the resistance of chloride penetration, freezing and thawing in concrete. It was showed that replacement of metakaolin was efficient for the reduction of the drying shrinkage.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.17 no.6
• /
• pp.61-69
• /
• 2013

This research is aimed to evaluate characteristics and dynamic modeling of MR damper for semi-active vibration control. A MR damper of semi-active type was designed and made for the purpose of controlling the vibration of a real-size model structure. Usually a semi-active control system equipped with a MR damper requires a dynamic model which expresses numerical data about the damping capacity and dynamic characteristics generated by a MR damper. To fulfil the requirement, a Power model and a Bingham model were particularly employed among many dynamic models of MR damper. Those models being contrasted with other ones, a dynamic test was carried out on the developed MR damper. In the test, excitation frequencies were conditioned to be 0.15 Hz, 1.0 Hz, and 2.0 Hz, and three different currents were adopted for each frequency. From these test results, it was found that displacement affected control capacity of the MR damper. The test results led to the identification of model variables for each dynamic model, on the basis of which a force-speed relation curve and expected damping force were derived and contrasted to those of the developed MR damper. Therefore, it was proven that the MR damper designed and made in this research was effective as a semi-active controller, and also that displacement of 2mm at minimum was found to be secured for vibration control, through the test using various displacements.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.21 no.1
• /
• pp.1-8
• /
• 2017

Three small scale hollow circular reinforced concrete columns with aspect ratio 4.5 were tested under cyclic lateral load with constant axial load. Diameter of section is 400 mm, hollow diameter is 200 mm. The selected test variable is transverse steel ratio. Volumetric ratios of spirals of all the columns are 0.302~0.604% in the plastic hinge region. It corresponds to 45.9~91.8% of the minimum requirement of confining steel by Korean Bridge Design Specifications, which represent existing columns not designed by the current seismic design specifications or designed by seismic concept. The longitudinal steel ratio is 2.017%. The axial load ratio is 7%. This paper describes mainly crack behavior, load-displacement hysteresis loop, seismic performance such as equivalent damping ratio, residual displacement and effective stiffness and flexural over-strength of circular reinforced concrete bridge columns with respect to test variable. The regulation of flexural over-strength is adopted by Korea Bridge Design Specifications (Limited state design, 2012). The test results are compared with nominal strength, result of nonlinear moment-curvature analysis and the design specifications such as AASHTO LRFD and Korea Bridge Design Specifications(Limited state design).

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.21 no.6
• /
• pp.543-553
• /
• 2008

Shipbuilding is a kind of ETO(Engineering To Order) industry which designs and produces a product in accordance to various requirement of customers, rules and regulations. Recently, the number of ordered ships has been increased by up to two or three times in each domestic shipyards. Most shipyards have been adopted 3D ship CAD, ERP(Enterprise Resource Planning) and APS(Advanced Planning System) to get an efficient product development and manufacturing system. However, not only the effective operation of 3D ship CAD, ERP and APS but also the production efficiency can be achieved only if product information management which can manages the product data is implemented in an integrated environment. Present study has suggested a systematic approach to implement a PLM system to manage the product data in early design shipbuilding. Also, a prototype of PLM is implemented to manage the product data in a basic ship-design. In the prototype system, a product structure and architecture of PLM is considered.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.26 no.1
• /
• pp.67-72
• /
• 2022

Concrete prevents corrosion of reinforcing bars due to its strong alkalinity. However, in the sea, strong alkali components with a pH of 12 to 13 are eluted, which adversely affects the ecological environment and growth of marine organisms. In this study, the mechanical properties and durability of the low alkali mortar were evaluated for the development of a low alkali mortar for the 3D printed artificial reefs. As a result of evaluation of strength characteristics, the α-35 mixture, which were produced with fly ash, silica fume and α-hemihydrate gypsum, satisfied the strength requirement 27 MPa in terms of compressive strength. As a result of pH measurement, it was found that mixing with alpha-type hemihydrate gypsum resulted in minimizing pH due to the the formation of calcium sulfate instead of calcium hydroxide production. As a result of the chloride ion penetration resistance test, the α-35 mixture exhibited the best performance, 3844C. As a result of measuring the length change over time, the α-35 mixture showed the shrinkage 33.5% less compared to the Plain mix.

• Economic Analysis
• /
• v.27 no.3
• /
• pp.1-32
• /
• 2021

This study empirically analyzes whether bank capital channel and risk-taking channel for monetary policy work for domestic banks in South Korea by analyzing the impact of the expansionary monetary policy on the rate spread between deposit and loan, capital ratio, and loan amount. For the empirical analysis, the Uhlig (2005)'s sign-restricted SVAR(Structural Vector Auto-Regression) model is used. The empirical results are as follows: the bank's interest rate margin increases, the capital ratio improves, risk-weighted asset ratio increases, and the amount of loans increases in response to expansionary monetary shock. This empirical results confirm that bank capital channel and risk-taking channel work in domestic banks, similar to the previous research results. The implications of this study are as follows. Although the expansionary monetary policy has the effect of improving the bank's financial soundness and profitability in the short term as bank capital channel works, it could negatively affect the soundness of banks by encouraging banks to pursue risk in the long run as risk-taking channel works. It is necessary to note that the capital ratio according to the BIS minimum capital requirement of individual banks may cause an illusion in supervising the soundness of the bank. So, the bank's aggressive lending expansion may lead to an inherent weakness in the event of a crisis. Since the financial authority may have an illusion about the bank's financial soundness if the low interest rate persists, the authority needs to be actively interested in stress tests and concentration risk management in the pillar 2 of the BIS capital accord. In addition, since system risk may increase, it is necessary to conduct regular stress tests or preemptive monitoring of assets concentration risk.

• Journal of Korea Port Economic Association
• /
• v.39 no.4
• /
• pp.163-190
• /
• 2023

Recently, a framework crystallizing as Environmental, Social, and Governance(ESG) has been exerting significant influence not only on corporate investment and management philosophies but also on national policies. This ESG framework is becoming an essential requirement for all organizations. It has become an obligation at the corporate and national levels, particularly in the maritime, port, and logistics sectors. Anticipating that the adoption and utilization of the ESG framework will reach higher levels when it becomes a necessity, this study utilized data from international organizations such as the United Nations Conference on Trade and Development(UNCTAD), the World Bank, and the World Economic Forum to analyze the impact of the ESG framework on national economic performance through the maritime, port, and logistics sectors using Partial Least Squares Structural Equation Modeling(PLS-SEM). The analysis revealed that while the ESG framework did not have a direct impact on the national economy, it manifested substantial indirect effects through maritime, port, and logistics sectors. Therefore, in these sectors, the establishment of the ESG framework should be recognized not only as an expenditure and obligation but also as a crucial investment that positively influences the national economic performance. The study's findings are limited by the absence of data beyond 2019 due to the impact of COVID-19. Therefore, it is anticipated that more accurate current effects can be ascertained when newer data becomes available.