• Journal of Advanced Marine Engineering and Technology
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• v.23 no.3
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• pp.300-310
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• 1999

A constant-volume combustion chamber is developed to measure the burnt gas temperature over the wide ranges of equivalence ratio from 1.5 to 2.7 and pressure from 0.1 to 2.7 and pressure from 0.1 to 6 MPa by two-color method. The combustion temperature is also calculated by the conventional two-region model. The premixed fuel rich propane-oxygen-inert gas mixtures under high pressures are simultaneously ignited by eight spark plugs located on the circumference of combustion chamber with 45 degree intervals. The eight converging flames compress the end gases to high pressures. The transmissiv-ity in the chamber center during the final stage of combustion at the highest pressure is measured by in situ laser extinction method. Comparisons are made with the combustion temperatures between two-color method and two-region model. It is found that the burnt gas temperature mea-sured by two-color method is higher than that calculated by two-region model because of being the negative temperature gradient on the calculation and the temperature distribution of light path-length on the measurement and the burnt gas temperature for the turbulent combustion is higher than that of the laminar combustion under the same conditions because the heat loss for turbulent combustion is lower due to the shorter combustion period.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.8
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• pp.1503-1512
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• 1992

The strength evaluation and life prediction on the corrosion part of structure is one of the most important subjects, as a viewpoint of reducing economic loss by regular inspection, maintenance, repair and replace. For this purpose, it has been difficult to obtain the available data on growth of pit depth or growth rate of each pit which depends on time. In this paper, the life prediction and strength evaluation method was suggested for the structure with irregular stress concentration part by surface corrosion. The statistical distribution pattern of corrosion depth and the degree of fatigue strength decline were confirmed according to corrosion period by artificial corrosion of SS41 steel. The life prediction and the fatigue strength evaluation of materials with consideration of the corrosion period on the extreme value statistic analysis by the data of maximum depth of corrosion and on random variable was studied.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.6
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• pp.84-91
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• 1999

The goal of this study is to analyse the stress and the strain occurring within the work piece at the fine-blanking process and hence to assume the size direction and a distribution chart of the shearing stress as the penetration of the punch is being increased trough the application of the FEM. For this analysis we introduced the piece-wise linear method in the non linear structural analysis program for large deformation sheet metal forming and we defined it as the problem of the non linear contact. Therefore we modeled the above problems as quadratic-nodded axi-symmetrical elements for the character-istics of the work piece. From the result of this analysis it was found that the shearing stress is a great deal occurred on the surface of the work piece during the beginning process of the punch penetration and it's effect is expected to influence importantly for the formation of burnish because the deeper is the penetration of the punch in the narrow clearance zone. the greater is the degree of the strain stress.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.4
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• pp.357-363
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• 2014

The electrolyte wetting phenomena in the electrode of lithium ion battery is studied numerically using a multiphase lattice Boltzmann method (LBM). When a porous electrode is compressed during roll-pressing process, the porosity and thickness of the compressed electrode are changed, which can affect its wettability. In this study, the change in electrolyte distribution and degree of saturation as a result of varying the compression ratio are investigated with two-dimensional LBM approach. We found that changes in the electrolyte transport path are caused by a reduction in through-plane pore size and result in a decrease in the wettability of the compressed electrode.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.9
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• pp.1238-1243
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• 2008

Domestic buffalo and cattle are two extremely important livestock species in worldwide agricultural production. In this paper, to investigate genetic diversity and divergence among swamp buffalo, river buffalo and cattle, 30 microsatellite markers were screened on 168 individuals sampled from five populations. Substantial differences were observed among the three groups of animals with respect to allele frequency distribution, allele size and polymorphism. The cattle sample (Mongolian) showed significantly higher genetic variability (0.674 of gene diversity, p<0.01), and the swamp and river buffalo samples displayed similar degree of genetic variation (0.536 in swamp and 0.546 in river, p = 0.92). Results of both phylogenetic tree and multivariate analysis could distinguish three groups of animals, suggesting their deep evolutionary divergence. Additionally, using $({\delta}{\mu})^2$ genetic distance, we estimated a divergence time of 1.7 million years between swamp and river buffalo that strongly supported distinct genetic origins for the two buffalo types.

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.2
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• pp.7-11
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• 1996

The size of pupil with pupillary light reflex is determined by the amount of a luminance. and it is dependent with the distribution function of the retinal illuminance which is the amount of transmittance for the external light due to the size of pupil, and the detector of cone and rod due to the amount of the luminance. The change of the pupil size with the luminance can be expressed with the mathematical model $$y(x)={\alpha}+{\beta}\frac{1}{1+{e}{x}{p}(x-x_0)/{\theta}}$$ where ${\alpha}$ is the size of the pupil diameter in a maximum value of the luminance, ${\beta}$ is the deviation of the pupil's diameter between maximum and minimum, ${\theta}$ is the parameter showed the degree of a sensitivity. Comparing with the experimental value of P.Moon et al, We known that the equation of the model is very compatible.

• The Journal of Asian Finance, Economics and Business
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• v.3 no.3
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• pp.17-26
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• 2016

This study investigates daily stock market anomalies in Chinese stock market, using nine most representative stock indices over an eleven year time period spanning from pre-financial crisis era to six years into the financial crisis. This research is the first to test the presence of the day of the week effect on stock returns in the Chinese stock exchanges during the financial crisis. We find that the day of week effects have been strongly significant in Chinese stock exchanges since 2004. However, unlike the previously found negative Monday effect and positive Friday effect in the U.S., Chinese stock market shows positive returns on Mondays and negative returns on Tuesdays. More importantly, the negative Tuesday effect is only significant after the inception of financial crisis. The results indicate a positive effect on Mondays and a negative effect on Thursdays. More importantly, we find a negative Tuesday effect during the financial crisis, which suggests a spillover of the Monday effect from the U.S. stock market. Our results shed some light on the degree of market efficiency in the largest emerging capital market in the world, and its increasingly close relationship with the U.S. capital market.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.9
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• pp.341-350
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• 2020

This study aims to verify the relationship between overseas activities and performance of Korea's SMEs during the last financial crisis. Whether overseas activity performance of enterprises differed was determined based on characteristic variables, including the degree of concentration on R&D and marketing. This study also examined how SMEs' international transactions and their performance differed based on internal variable such as the level of stock holding and firm size. This study developed a model for analyzing the relationship between the level of internationalization and performance of Koran SMEs listed in the KOSDAQ. We used firm-level data, including annual reports and various data sources such as the KISVALUE program. To smooth annual fluctuations in accounting data, we used a three-year average from 2006 to 2009 for each variable in the study. The results showed that proactive overseas activities ultimately had a positive effect on an enterprise's performance, even though it initially had a negative effect. Therefore, enterprises should focus their capacity on R&D and marketing environment. Although numerous studies have focused on the relationship between overseas activities and performance of enterprises, the present study analyzed whether enterprises should continuously engage in overseas activities and what capacities they should strengthen during a global economic recession.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.4989-4992
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• 2013

Aim: To compare p16INK4a immunocytochemistry with the HPV polymerase chain reaction in predicting high grade cervical squamous intraepithelial lesions. Materials and Methods: This diagnostic case-control study was conducted from January 2010 until December 2010. We obtained 30 samples, classified according to the degree of cervical intraepithelial neoplasia (CIN): 11 samples for CIN 1, 9 samples for CIN 2, and 10 samples for CIN 3. HPV PCR, p16INK4a immunocytochemistry, and histopathological examination were performed on all samples. Statistical analysis was conducted using SPSS 20.0. Results: In predicting CIN 2-3, we found p16INK4a to have similar specificity and positive predictive value as HPV PCR (95%, 97.2% vs 96.7%), but better sensitivity (87.5% vs 72.5%) and negative predictive value (82.1% vs 67.6%). The most prevalent types of high-risk HPV in our study were HPV 33, 35, 58, 52, and 16. Conclusions: p16INK4a has better diagnostic values than HPV PCR and may be incorporated in the triage of ASCUS and LSIL to replace HPV PCR. Genotype distribution of HPV differs in each region, providing a challenge to develop HPV vaccines based on the epidemiology of HPV in that particular region.

• Journal of the Korean Institute of Navigation
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• v.13 no.1
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• pp.55-61
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• 1989

Nowadays much efforts for evaluating the productivity of port physical distribution system to meet the rapid change of the port and shipping circumstances has been made continuously all over the world. The major part of these efforts is the improvement of the productivity of cargo handling system. The cargo equipment system as infrastructure in the cargo handling system is organized well in some degrees, but the management system of manpower as upper structure is still remained in an insufficient degree. There is little study, so far, on a systematic research for the management of port labor gang, and even those were mainly depended on rule of thumb. The object of this study is to introduce the method of optimal allocation and assignment for the labor gang in single ship, which was suggested as a first stage in dealing with them generally. The problem of optimal allocation and assignment of the labor gang can be (I) formalized with multi-stage allocation and assignment of the labor gang can be. (II) dealt with two stages in form of hierarchic structure and moreover, (III) The optimal size of labor gang was obtained through dynamic programming from the point of minimizing the summation of labor gang in every stage, (IV) For the problem of optimal assignment, the optimal policy was determined at the point of minimizing the summation of movement between hatches.