• Advances in nano research
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• v.7 no.5
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• pp.293-310
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• 2019

In this paper, thermal-buckling behavior of the functionally graded (FG) nanocomposite plates reinforced with graphene oxide powder (GOP) is studied under three types of thermal loading once the plate is supposed to be rested on a two-parameter elastic foundation. The effective material properties of the nanocomposite plate are considered to be graded continuously through the thickness according to the Halpin-Tsai micromechanical scheme. Four types of GOPs' distribution namely uniform (U), X, V and O, are considered in a comparative way in order to find out the most efficient model of GOPs' distribution for the purpose of improving the stability limit of the structure. The governing equations of the plate have been derived based on a refined higher-order shear deformation plate theory incorporated with Hamilton's principle and solved analytically via Navier's solution for a simply supported GOP reinforced (GOPR) nanocomposite plate. Some new results are obtained by applying different thermal loadings to the plate according to the GOPs' negative coefficient of thermal expansion and considering both Winkler-type and Pasternak-type foundation models. Besides, detailed parametric studies have been carried out to reveal the influences of the different types of thermal loading, weight fraction of GOP, aspect and length-to-thickness ratios, distribution type, elastic foundation constants and so on, on the critical buckling load of nanocomposite plates. Moreover, the effects of thermal loadings with various types of temperature rise are investigated comparatively according to the graphical results. It is explicitly shown that the buckling behavior of an FG nanocomposite plate is significantly influenced by these effects.

• The Journal of Information Systems
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• v.11 no.1
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• pp.29-49
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• 2002

Recently the paradigm of business management has changed. The businesses have restored to ERP or BPR to integrate their information system. But now they are trying to find out a new competitiveness in tacit knowledge of individuals. The creative company has come to put much weigh on the value of their employee′s "non-patternized" knowledge. And this trend has seen a development into a theory of knowledge management in which "non-patternized" knowledge, along with explicit knowledge, is also considered as a source of competitiveness. With the hypothesis that the recognition of the knowledge management and the utilization of the information technology will have influence on the integration of the integrating the information system information system into a new phase, this study carries out a research on the effects of knowledge management and information technology on management achievement. According to this study the distribution of knowledge has an effect on the integration of information system and management achievement. The asset of knowledge, however, has little effect on them. This means that the recognition of the asset of knowledge alone can't affect the management achievement, but when combined with the recognition of the distribution of knowledge, it can have influence on the management achievement. Thus, a company has to enhance the recognition of the distribution of knowledge. And with this, a company can have a business management based on management achievement and the integration of information system utilizing information technology and the recognition of knowledge management. A company has to promote it business achievement by integrating the information system utilizing information technology and recognizing knowledge management.

• Journal of Korean Society for Quality Management
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• v.51 no.4
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• pp.663-675
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• 2023

Purpose: Skewness is an indicator used to measure the asymmetry of data distribution. In the past, product quality was judged only by mean and variance, but in modern management and manufacturing environments, various factors and volatility must be considered. Therefore, skewness helps accurately understand the shape of data distribution and identify outliers or problems, and skewness can be utilized from this new perspective. Therefore, we would like to propose a statistical quality control method using skewness. Methods: In order to generate data with the same mean and variance but different skewness, data was generated using normal distribution and gamma distribution. Using Minitab 18, we created 20 sets of 1,000 random data of normal distribution and gamma distribution. Using this data, it was proven that the process state can be sensitively identified by using skewness. Results: As a result of the analysis of this study, if the skewness is within ± 0.2, there is no difference in judgment from management based on the probability of errors that can be made in the management state as discussed in quality control. However, if the skewness exceeds ±0.2, the control chart considering only the standard deviation determines that it is in control, but it can be seen that the data is out of control. Conclusion: By using skewness in process management, the ability to evaluate data quality is improved and the ability to detect abnormal signals is excellent. By using this, process improvement and process non-sub-stitutability issues can be quickly identified and improved.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.264-267
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• 2004

The conventional testing as IEC-60587 is widely used in surface aging measurement of outside insulator those testing can carry out very short time in Lab testing. Also IEC-60587 testing is able to offer the standard judgement of relative degradation level of out side HV machine. Therefore it is very useful method compare to previous conventional tracking testing method and effective Lab testing method, But surface discharges(SD) have very complex characteristics of discharge pattern so it is required estimation research to development of precise analysis method. In recent, the study of IRR Camera is carrying out discover of temperature of power equipment through condition diagnosis and system development of degradation diagnosis.

• Proceedings of the Korean Reliability Society Conference
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• 2005.06a
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• pp.121-129
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• 2005

In this paper, we consider a periodic preventive maintenance(PM) policy in which each PM reduces the hazard rate of amount proportional to the failure intensity, which increases since the last PM and slows down the wear-out speed to that of new one. And the proportion of reduction in hazard rate decreases with the number of PMs. Our model is similar to $ARI_1$ proposed by Doyen and Gaudoin(2004) in the sense of reduction of hazard rate. Our model has totally different wear-out pattern of hazard rate after PM's, however, and the proportion of reduction depends on the number of PM's. Assuming that the system undergoes only minimal repairs at failures between PM's, the expected cost rate per unit time is obtained. The optimal number N of PM and the optimal period x, which minimize the expected cost rate per unit time are discussed. Explicit solutions for the optimal periodic PM are given for the Weibull distribution case.

• The Korean Journal of Ecology
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• v.11 no.1
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• pp.29-36
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• 1988

This present study has been carried out to examine the correlation between the distribution of the coliform bacterial plasmids and the viability test against heavy metals in the upper stream of Han river(Gapyung; clean water) and the its basin (Anyang Cheon; polluted water). And the distribution of plasmids were examined to be used as trophic indicator for analysis between the clean and polluted waters. 1. A total of 110 isolates were analyzed for the presence of plasmids by means of the boiling method and agarose gel techniques. Plasmids were significantly more frequent in the strains which had been isolated from the clean water (14.3%). Also, there were much higher multiplicity of plasmids at the polluted water(41.0%), compared with the clean water (33.0%). By the comparision between molecular weight of bacterial plasmids in the clean water and those of polluted water, there were no significant differences of the clean water from the polluted water, to such extent as 30.0%, 28.6%, respectively, in frequency for occurrence of high molecular weight plasmids iver 35.8% Mdal. 2. Each isolate was carried out the resistance test for mercury(10-5M), nickel(10-3M) and arsenic (0.1%). At the polluted site, the survival ability of the plasmid-carrying straings(Hg, 31.0%l Ni, 5.7%; As, 65.7%) was higher than that of the non plasmid-carrying strains(Hg, 12.1%; Ni, 3.0%; As, 54.6%). This trend was more remarkable in the clean site (plasmid-carrying strains: 16.7%,-,-). As a result it is suggested that plasmids could be used as an indicator of a certain types of water pollution. In addition, heavy metals might have inflyenced, some extent, to the distribution of plasmids in the environment which has been surveyed in the present study.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.5 no.1
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• pp.143-150
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• 1992

The clinical study was carried out the 33 patients with Allergic rhinitis who had been treated by Ga-Mi-tong-Gyu-tang from 1992.1 to 1992.9. The results were summarized as follows. 1. Distribution of sex : male($54.5\%$), female($45.5\%$) In the distribution of age, 30 age group made up $27.3\%$, and 10s, 40s, 20s in descending order. 2. Distribution of illness period : 1 - 5 under years($66.7\%$) , 6month-l under year($18.1\%$), 5-10 under years($15.2\%$). 3. Distribution of symptoms and signs, nasal discharge was $100\%$, sneezing was $93.9\%$, stuffy nose was $84.8\%$, nasal cooling sign was $33.3\%$. 4. Past history : Asthma was $15.1\%$, gastritis was $15.1\%$, genyantritis was $9.0\%$, deviation of the nasal septum was $3.0\%$, bronchitis was $3.0\%$. 5. In the general paranasal sinuses X-ray examination and anterior rhinoscopy : $45.4\%$ have hypertrophy of concha, $9.0\%$ have genyantritis, $6.0\%$ have deviation of the nasal septum. 6. Distribution of period in descending order: 1-10 days($57.6\%$), 11-20 days ($36.4\%$), 21-30 days($6.0\%$) 7. Distribution of Medicine for external in descending order : 11-20($42.4\%$), 21-30($22.7\%$), 31-40 were each $3.0\%$ 8. The improvement rate in symptoms and signs was $88.8\%$ expect None.

• The Journal of Industrial Distribution & Business
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• v.9 no.2
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• pp.65-72
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• 2018

Purpose - One of the biggest problems in the e-learning distribution process is the lack of quality content and learners' discredit in e-learning content. In order to respond to the various demands of the corporate education field appropriately, it is necessary to search for directions of new e-learning models that are out of traditional e-learning contents. The purpose of this study is to identify recent trend issues related to corporate e-learning and to suggest directions for development. Research design, data, and methodology - Based on the literature review, trend issues that should be considered important in corporate e-learning were derived. Online survey was conducted to evaluate the importance-feasibility of each issue to 13 experts on e-learning and corporate education. The contents of the questionnaire are as follows: 1) recognition of importance and feasibility of trend issues to be considered important in the future corporate education field; 2) factors to be considered in developing future e-learning contents. Results - Six trends derived from a comprehensive literature review. The most important e-learning trends for corporate education field were 'mobile learning', 'micro learning', 'blended learning', 'social learning', 'adaptive learning', 'engaged learning'. As a result of evaluating the importance and feasibility of each issue, experts point out that 'mobile learning' and 'micro learning' should be actively considered for introduction and utilization at present. In addition, 'social learning' and 'blended learning' need to be actively considered in the near future. On the other hand, experts recognized that 'adaptive learning' and 'engaged learning' need to be prepared from a long-term perspective. Conclusions - There are two main reasons for this result. First, in corporate e-learning, it is important to 1) be able to update on time, 2) the connection with the workplace is important. Second, it requires realistic verification of the expected performance of the learning model. To be considered part of the future are as follows: First, the value and effectiveness of the new e-learning type should be studied. Seconds, e-learning contents should be developed through adopting SAM or Agile methodology. Through this process, we would be able to enhance the quality in e-learning content.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.2
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• pp.39-53
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• 2022

The purpose of this study is to find out the applicability of LANDIS-II model to Korea. The case study was carried out in Daecheong Dam basin. In order to operate the model, a total of 63,107 cells of 100x100m unit were constructed, each cell consists of ecoregion map, initial communities map, plant physiological data, and climate change prediction data using SSP2-4.5 scenario. Forest distributions of year 2050 and 2100 were predicted by distribution intensity and interference among trees based on field surveys of 147 points in 2020. As a result, trees of decreased distribution area in the future are in the order of Quercus mongolica, Pinus rigida, Pinus densiflora and Robinia pseudoacacia, which characterized vulnerable to the effects of climate change or artificially planted trees. While warm climate trees of Quercus variabilis, Quercus serrata, Quercus acutissima and Quercus aliana are predicted to increase their distribution area in the order. These results analyzed using the LANDIS-II model are consistent with the studies on potential natural vegetation and succession tendency in Korea. In conclusion, the applicability of LANDIS-II model in Korea is highly effective and it is also expected to serve as a scientific basis for determining forest policies on afforestation and restoration.

• Journal of the Korean Institute of Navigation
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• v.21 no.1
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• pp.1-11
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• 1997

Because of the sharp increase of its export and import container cargo volumes contrast to the lack of related Container Terminal facility, equipment and inefficient procedure, there is now heavy container cargo congestions in Pusan Container Terminal. As a result of such a situation, many container ships avoid their calls into Pusan port. This is a major cause that in tum kads to weakening intemational competitiveness of the Korean industry. This study, therefore, aims are to make a quantitative analysis of Container Terminal System through the computer simulation, especially focusing on its 4 sub-system of a handling system, 'it is checked whether the current operation is being performed effectively through the computer simulation. The overall findings are as folIows; Firstly, average tonnage of the ships visiting the BCTOC was 32,360 G/T in from January '96, to may '96. The average arrival interval and service time of container ships at BCTOC are 5.63 hours and 18.67 hours respectively. Ship's arrival and service pattern at BCTOC was exponential distribution with 95% confidence and Erlang-4 distribution with 99% confidence. Secondly, average waiting time and number of ships was 9.9 hours, 235 ships(38%) among 620 ships. Number of stevedoring container per ship was average 747.7 TED, standard deviation 379.1 TEU and normal distribution with 99% confidence. Thirdly, from the fact that the average storage days of containers at BCTOC are 2.75 days (3.0 days when import, 2.5 days when export). it is founds that most containers were transfered to the off-dock storage areas with the free periods(5 days when import, 4 days when export), the reason for which is considered to be the insufficient storage area at BCTOC. Fourthly, in the case of gate in-out at BCTOC, occupied containers and emptied containers are 89% and 11% respectively in the gate-in, 75% and 25% seperately in the gate-out. Finally, from the quantitative analysis results for container terminal at BCTOC, ship's average wating time of ships was found to be 20.77 hours and berth occupancy rate(${\rho}$) was 0.83. 5~6 berths were required in order that the berth occupancy rate(${\rho}$) may be maintained up to 60% degree.