• Journal of the Korean Operations Research and Management Science Society
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• v.11 no.1
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• pp.12-23
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• 1986

The minimum attractive rate of return (MARR) has been used for many years as a decision criterion in engineering economic analysis. Typically, inflation has been either ignored in such studies or considered by adjusting each of the individual cash flows associated with a project for inflation, frequently a lengthy process. This research investigates a new decision criterion for economic analysis, the comparative rate of return (CRR). The CRR is defined to be the minimum rate of return earned on uninflated cash flows of proposed expenditures is simplified, since the analysis can be performed on the uninflated cash flows. The research presents a derivation of the CRR and investigates its relationships to the MARR, inflation rate project cash flows and project life.

• Journal of the Korean GEO-environmental Society
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• v.21 no.1
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• pp.13-19
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• 2020

Recently, as the number of earthquakes increases in the Korean Peninsula and surrounding area, the importance of earthquake countermeasures and seismic design has been increasing. As a result, interest and concerns about liquefaction, which is one of the problems that concern the earthquake, are increasing. There are various methods that can assess the possibility of liquefaction by using geotechnical information for specific ground. However, direct comparisons of each method are not yet available. In this study, the two methods using the SPT-N value and the shear wave velocity among the methods for estimating the Cyclic Resistance Ratio (CRR) value required for the simplified liquefaction assessment method were compared. And the correction of the ground information required to use the two methods respectively was compared. As a result, more accurate evaluation results were obtained when the CRR value is calculated using the SPT-N values.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.4
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• pp.1-13
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• 2009

Liquefaction is a significant threat to structures on loose saturated sandy soil deposits in the event of an earthquake, and can often cause catastrophic damage, economic loss, and loss of life. Nevertheless, the Korean peninsula has for a long time been recognized as a safe region with respect to the hazard of liquefaction, as the peninsula is located in a moderate seismicity region, and there have been no reports of liquefaction, with the exception of references in some historical documents. However, some earthquakes that have recently occurred in different parts of the world have led to liquefaction in non-plastic silty soils, a soil type that can be found in many of the western coastal areas of Korea. In this study, we first present procedures for evaluating the liquefaction potential, and calculate the liquefaction potential index (LPI) distribution at two western coastal sites using both piezocone penetration test (CPTu) data and standard penetration test (SPT) data. The LPI is computed by integrating liquefaction potential over a depth of 20m, and provides an estimate of liquefaction-related surface damage. In addition, we compared the LPI values obtained from CPTu and SPT, respectively. Our research found that the CRR values from CPTu were lower than those from the SPT, particularly in the range between 40 and 120 for the corrected tip resistance, (qc1N)CS, from the CPTu, or in the range of CRR less than 0.23, resulting in relatively high LPI values. Moreover, it was observed that the differences in the CRR between the two methods were relatively higher for soils with high fine contents.

• The Journal of Asian Finance, Economics and Business
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• v.5 no.1
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• pp.29-41
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• 2018

These days, corporate risk management has become a major concern in the corporate world. Companies in the global environment are exposed to diverse kinds of risks that are affecting the decisions of investors and other stakeholders. Therefore, companies are expected to not only identify and manage risks but also voluntarily report the same to the stakeholders. Increasingly, standard setters and regulators are requiring firms to disclose such information. On the contrary, there also exists a perception that risk reporting can create a negative impression among the stakeholders about the future of the company. In line with such growing dilemma for risk disclosures, the issue of corporate risk reporting (CRR) has been receiving immense emphasis from the accounting academicians. The main objective of this article is to conduct a comprehensive literature review on corporate risk disclosures. In order to fulfill this objective, at first, a summary of the relevant available literature is presented to identify the current regulations on risk reporting, existing trends of CRR research and theories applied in research. Then, through analysis, several research avenues are identified. It is expected that if these dimensions are explored by the future researchers, a better and broader understanding of the risk reporting practices can be achieved.

• Korean Journal of Optics and Photonics
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• v.17 no.6
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• pp.544-547
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• 2006

A time-domain modeling approach is used to study characteristics of a widely tunable coupled-ring reflector (CRR) laser diode(LD). The CRR consists of a bus waveguide and two coupled ring resonators coupled to the bus without resorting to distributed Bragg grating structure. The tuning range can be a few tens of nanometers with a side mode suppression ratio exceeding 35dB through the adjustment of currents into the phase control sections in the rings. The CRR laser diode has long effective cavity length compared to conventional laser diodes. Accordingly, a broad additional resonance peak in the amplitude modulation characteristics is observed between 20 to 30 GHz, implying the extension of amplitude modulation bandwidth.

• Journal of the Earthquake Engineering Society of Korea
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• v.24 no.5
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• pp.197-209
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• 2020

Evidence of liquefaction during the 2017 Pohang earthquake has highlighted the urgent need to evaluate the current seismic design standard for liquefaction in Korea, particularly the liquefaction triggering standard. With the simplified method, which is the most popular method for evaluating liquefaction triggering, the factor of safety for liquefaction triggering is calculated via the cyclic stress ratio (CSR) and the cyclic resistance ratio (CRR). The parameters in the CSR and CRR have undergone changes over time based on new research findings and lessons learned from liquefaction case-histories. Hence, the current design standard for liquefaction triggering evaluation in Korea should also reflect these changes to achieve seismic safety during future earthquakes. In this study, liquefaction susceptibility criteria were discussed initially and this was followed by a review of the current liquefaction triggering codes/guidelines in other countries and Korea. Next, the parameters associated with the CSR such as the maximum ground acceleration, stress reduction factor, magnitude scaling factor, and overburden correction factor were discussed in detail. Then, the evaluation of the CRR using the SPT N-value and CPT qc-value was elaborated along with overburden and clean-sand correction factors. Based on this review of liquefaction triggering evaluation standards, recommendations are made for improving the current seismic design standard related to liquefaction triggering in Korea.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2019.10a
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• pp.83-83
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• 2019

Increasing the CO₂ concentration in the atmosphere induce high temperature and rising sea levels. So the technology that capture and reuse of the CO₂ have been recently become popular. Among other methods, CRR(CO2₂ reduction reaction) is typical method of CO₂ reusing. Electrocatalyst can show more higher efficiencies in CRR than photocatalyst because it doesn't use nature source. Nowadays, finding high efficient electrocatalyst by controlling electronic (affected by stoichiometry) and geometric (affected by atomic arrangement) factors are very important issues. Mono-atomic electro-catalyst has limitations on controlling binding energy because each intermediate has own binding energy range. So the Multi-metallic electro-catalyst is important to stabilize intermediate at the same time. Carbon monoxide(CO) which is our target product and important feedstock of useful products. Au is known for the most high CO production metal. With copper, Not only gold/copper has advantages which is they have FCC packing for easily forming solid solution regardless of stoichiometry but also presence of adsorbed CO on Cu promotes the desorption of CO on Au because of strong repulsion. And gold/copper bi-metal catalyst can show high catalytic activity(mass activity) although it has low selectivity relatively Gold. Actually, multi-metallic catalyst structure control method is limited in the solution method which is takes a lot of time. In here, we introduce CTS(carbo thermal shock) method which is using heat to make MMNP in a few seconds for making gold-copper system. This method is very simple and efficient in terms of time(very short reaction time and using carbon substrate as a direct working electrode) and increasing reaction sites(highly dispersed and mixing alloy structures). Last one is easy to control degree of mixing and it can induce 5 or more metals in one alloy system. Gold/copper by CTS can show higher catalytic activity depending on metal ratio which is altered easily by changing simple variables. The ultimate goals are making CO₂ test system by CTS which can check the selectivity depending on metal types in a very short time.

• Journal of Acupuncture Research
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• v.23 no.3
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• pp.177-190
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• 2006

Objectives : It has long been known about the anticancer effect of GRR-HAS, however, it has not been systemically determined the differentially regulated genes by GRR-HAS in cancer cells. The purpose of this study is to screen the GRR-HAS mediated differentially expressed genes in cancer cells such as HepG2 hepatoma cell lines. Oligonucleotide microarray and proteomic approaches were employed to screen the differential expression genes. Methods : GRR~HAS was prepared by boiling and stored at $-70^{\circ}C$ until use. Cells were treated with various concentrations of GRR-HAS (0.1, 0.5, 1.5, 10, $20mg/m{\ell}$) for 24 h. Cell toxicity was tested by MTT assay. To screen the differentially expressed genes in cancer cells, cells were treated with $1.5mg/m{\ell}$ of GRR-HAS. For oligonucleotide microarray assay, total RNA was used for gene expression analysis using oligonucleotide genechip (Human genome Ul33 Plus 2.0., Affimatrix Co.). For proteomic analysis, total protein was analyzed by 2D gel electrophoresis and Q-TOF mass spectrometer. Results : It has no cytotoxic effects on both HepG2 cells in all concentrations(0.1, 0.5, 1.5, 10,$20mg/m{\ell}$). In oligonucleotide microarray assay, the number of more than twofold differentially regulated known genes was 320 with 6 up-regulated and 314 down-regulated genes in HepG2 cells. In proteomic analysis, three spots were identified by 2D-gel electrophoresis and Q-TOF analysis. One down -regulated protein was protein disulfide isomerase and up-regulated proteins were fatty acid binding protein 1 and 14-3-3 gan1lTIa protein by $1.5mg/m{\ell}$ of CRR-HAS. Discussion : This study showed the comprehensive gene expression analysis using oligonucleotide microarray for the screening of GRR-HAS mediated differentially regulated genes. These results will provide a better application of GRR-HAS in cancer field and drug target development.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.4
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• pp.371-383
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• 2012

Shaping the root canal system to maintain original canal curvature is essential to clinical success in endodontic treatment. Opposed to most root canals that are curved, endodontic instruments are made from straight metal blanks. They have a tendency of straightening the root canal during preparation and frequently result in procedural errors. A new treatment method to maintain original canal curvature during shaping has been introduced for preventing procedural errors. The aim of this study was to compare the ability of instruments to maintain original canal curvature of continuous rotary system and single file system. Thirty ISO 15, 0.02 taper, Endo Training Blocks(Dentsplay Maillefer) were used. Specimens were assigned to 1 of 3 groups for shaping: specimens in group 1 were shaped with ProFile #20/.06 at the WL. Specimens in group 2 were shaped with Mtwo #35/.04 at the WL. Specimens in group 3 were shaped with WaveOne Primary reciprocating files at the WL after the glide path was achieved with PathFile. Pre- and postinstrumentation digital images were superimposed and processed with Matlab r2010b(The MathWorks Inc, Natick, MA) software to analyze the curvature-radius ratio(CRr), representing canal curvature modification. Data for comparison on the ability of instruments to maintain original canal curvature depending on each Ni-Ti file were analyzed with 1-way ANOVA(P<.05). Data for comparison on the ability of instruments to maintain original canal curvature depending on each Ni-Ti file system were analyzed with independent t-test(P<.05). A statistically significant difference(P<0.05) was noted on each Ni-Ti file. ProFile and WaveOne instrumentations maintained the original canal curvature significantly better(P<0.05) than Mtwo file. There were no significant difference(P>0.05) between continuous rotary system and single file system. Under the conditions of this study, ProFile and WaveOne instruments maintained the original curvature significantly better than Mtwo file and were less modification of the canal curvature compared. There was no significant difference between continuous rotary system and single file system in shaping of simulated canals. As clinical practitioners, it may be advantages to use hybrid approach when root canal shapes depending on the design and usage of Ni-Ti files.

• Journal of Pharmacopuncture
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• v.9 no.2
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• pp.39-47
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• 2006

Objective : It has long been known about the anticancer effect of GRR-HAS, however, it has not been systemically determined the differentially regulated genes by GRR-HAS in cancer cells. The purpose of this study is to screen the GRR-HAS mediated differentially expressed genes in cancer cells such as SNU484 gastric cancer cell lines. Oligonucleotide microarray approache was employed to screen the differential expression genes. Methods : GRR-HAS was prepared by boiling and stored at $-70^{\circ}C$ until use. Cells were treated with various concentrations of GRR-HAS(0.1, 0.5, 1.5, 10, 20mg/ml) for 24 h. Cell toxicity was tested by MTT assay. To screen the differentially expressed genes in cancer cells, cells were treated with 1.5mg/ml of GRR-HAS. For oligonucleotide microarray assay, total RNA was used for gene expression analysis using oligonucleotide Genechip (Human genome Ul33 Plus 2.0., Affimatrix Co.). Results : It has no cytotoxic effects on both HepG2 and SNU484 cells in all concentrations(0.1, 0.5, 1.5, 10, 20mg/ml). In oligonucleotide microarray assay, in SNU484 cells, the number of more than twofold up-regulated genes was 346. The number of more than twofold down-regulated genes was 9. Discussion : This study showed the comprehensive gene expression analysis using oligonucleotide microarray for the screening of GRR-HAS mediated differentially regulated genes. These results will provide a better application of GRR-HAS in cancer field and drug target development.