• The Journal of Korean Association of Computer Education
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• v.18 no.5
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• pp.63-70
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• 2015

In the environment that the complex conditions need to be satisfied, skyline query have been applied to various field. To processing a skyline query in centralized scheme, several techniques have been suggested and recently map/reduce platform based approaches has been proposed which divides data space into multiple partitions for the vast volume of multidimensional data. However, the performances of these approaches are fluctuated due to the uneven data loading between servers and redundant tasks. Motivated by these issues, this paper suggests a novel technique called MR-DEAP which solves the uneven data loading using the random sampling. The experimental result gains the proposed MR-DEAP outperforms MR-Angular and MR-BNL scheme.

• Journal of Korean Society of Forest Science
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• v.69 no.1
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• pp.6-12
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• 1985

A computer program for stem analysis has been prepared by using BASIC language. Annual-ring counts and other input data can be directly entered for necessary calculation, and outputs are data lists, cross-section areas, age-height relationships, growth rates, total, annual, and mean increments of height, D.B.H. and volume for an individual tree. The sectional log volumes are calculated by Huber's formula, and the growth rates by Pressler's in this program. A copy of the program listing is in appendix I.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.177-186
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• 2011

We can expect reduction of the sunlight absorption quantity to a structure and an earth surface, a decline of the surface temperature and a decline of the heat transport volume in what there is a method I give the sunlight reflectance in the aspect to the surface of the building by painting sunlight high reflectance paint, and to reduce the sunlight absorption quantity to a structure and an earth surface and does so, and, in addition, a method high water retentivity of tree planting and the road surface of the city space uses evaporation latent heat of the water by making it, and to restrain a rise in temperature is thought about. and It is thought that I reduce the sunlight absorption quantity to not only the structure but also other structures and attention gathers to the reflexive reflector reflecting in the direction again and it is wide as a marker of a board and the clothing of the traffic sign and is used the incidence energy from a source of light for this reflexive reflector now by there is it and devises surface structure again, and controlling reflection directivity for the sunlight for the purpose of raising night visibility.

• Journal of Forest and Environmental Science
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• v.27 no.3
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• pp.157-167
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• 2011

This study was conducted to analyze the stand structure and growth characteristics along different elevations of Pinus koraiensis natural forests located at mean elevation 1,300 m (site1), 900 m (site2) and 600 m (site3) on Mt. Seorak. Mean DBH and height of P. koraiensis were 25.4 cm and 12.3 m in site1, while that of site2 and 3 were over 40 cm and 20 m, respectively. For this reason, there was 5 times difference of single tree volume between site1 and other sites(p<0.05). Mean ringwidth increment of P. koraiensis was 1.1 mm/yr in site1, 1.5 mm/yr in site2 and 2.6 mm/yr in site3. However, recent growth of ringwidth has increased by 8.6% in site1, whereas site2 and 3 have fallen by approximately 50% over the last 10 years. These results signify that the growth and distribution of natural P. koraiensis are effected by different climatic environment along elevations.

• International Journal of Computer Science & Network Security
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• v.21 no.9
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• pp.31-40
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• 2021

The increasing number of credit card fraud cases has become a considerable problem since the past decades. This phenomenon is due to the expansion of new technologies, including the increased popularity and volume of online banking transactions and e-commerce. In order to address the problem of credit card fraud detection, a rule-based approach has been widely utilized to detect and guard against fraudulent activities. However, it requires huge computational power and high complexity in defining and building the rule base for pattern matching, in order to precisely identifying the fraud patterns. In addition, it does not come with intelligence and ability in predicting or analysing transaction data in looking for new fraud patterns and strategies. As such, Data Mining and Machine Learning algorithms are proposed to overcome the shortcomings in this paper. The aim of this paper is to highlight the important techniques and methodologies that are employed in fraud detection, while at the same time focusing on the existing literature. Methods such as Artificial Neural Networks (ANNs), Support Vector Machines (SVMs), naïve Bayesian, k-Nearest Neighbour (k-NN), Decision Tree and Frequent Pattern Mining algorithms are reviewed and evaluated for their performance in detecting fraudulent transaction.

• International Journal of Computer Science & Network Security
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• v.23 no.8
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• pp.26-32
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• 2023

Hajj is a fundamental pillar of Islam that all Muslims must perform at least once in their lives. However, Umrah can be performed several times yearly, depending on people's abilities. Every year, Muslims from all over the world travel to Saudi Arabia to perform Hajj. Hajj and Umrah pilgrims face multiple issues due to the large volume of people at the same time and place during the event. Therefore, a system is needed to facilitate the people's smooth execution of Hajj and Umrah procedures. Multiple devices are already installed in Makkah, but it would be better to suggest the data architectures with the help of machine learning approaches. The proposed system analyzes the services provided to the pilgrims regarding gender, location, and foreign pilgrims. The proposed system addressed the research problem of analyzing the Hajj pilgrim dataset most effectively. In addition, Visualizations of the proposed method showed the system's performance using data architectures. Machine learning algorithms classify whether male pilgrims are more significant than female pilgrims. Several algorithms were proposed to classify the data, including logistic regression, Naive Bayes, K-nearest neighbors, decision trees, random forests, and XGBoost. The decision tree accuracy value was 62.83%, whereas K-nearest Neighbors had 62.86%; other classifiers have lower accuracy than these. The open-source dataset was analyzed using different data architectures to store the data, and then machine learning approaches were used to classify the dataset.

• Journal of Korean Society of Forest Science
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• v.49 no.1
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• pp.6-10
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• 1980

The witches' broom disease of Paulownia tomentosa (Thunb.) Steud with which mycoplasmalike organisms are associated is widespread throughout Korea and poses serious threat to the cultivation of paulownia. Attempt was made to investigate the feasibility of field control of the disease with oxytetracycline hydrochloride (OTC). A total of 84 paulownia trees (6 year-old, DBH: 10-15cm) exhibiting severe symptoms of witches' broom were selected and treated during March to September. Solution of 1-10g of OTC dissolved in 0.1­2.0 of water was transfused into infected trees with gravity flow method from a dark-brown colored plastic reservoir (11 volume) through plastic tubes (1.2m long) connected to 2-4 holes (5 mm in diameter and 4-5cm in depth) bored in the basal part of the tree trunks (Fig. 1 and 2). Of 60 diseased paulownia trees injected with 2g of OTC in 0.1-2.0l of water during May to September, 1979, 58 trees resulted in complete remission of symptom development and resumption of healthy new growth at least up to September, 1980 when the last observation of the effect of OTC treatment for this experiment was made. The rest of two trees were dead probably due to too severe infection. Of 24 paulownia trees treated in March and April, 1979 complete remission of symptom development was obtained with 8 trees, and nine trees were partially prevented from symptom development in the following season. The remaining 7 trees were dead due to failure in uptake of OTC and partly because the trees were in too far advanced stage of infection. Application of highly concentrated solution of 2g of OTC dissolved in 0.1-0.2l of water per tree was just as effective as the 2g/1-2l treatment. Injection of 2g/1-2l required 3-4 days while treatment of 2g/0.1-0.2l reduced the time for injecting one tree down to less than 24 hrs. The result of this experiment demonstrates that basal trunk injection of 2g OTC/0.1-0.2l/tree is feasible for field control of paulownia witches' broom, provided that tree injection is performed in actively growing season (May-September) and at the initial stage of disease development.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.678-688
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• 2021

This study was conducted to provide growth characteristics and stand information in preparation for natural regeneration method and silvicultural treatment of seed tree method in Korean red pine stands by using the field inventoried data 18 years after the seed tree regeneration method in 2001 and analyzing the stand and sapling characteristics. The study area was located in the Research Forest of Kangwon National University, Chuncheon-si, Gangwon-do. In November 2018, we collected tree measurement factors, such as diameter at breast height (DBH), height, crown class, stem quality, tree age, and annual height increment on the established plots. We calculated the basal area, volume, height-diameter ratio (HD ratio), and additional stand density variables such as the relative density and %stocking to analyze the managed stands. The number of mother trees was 58 trees/ha, with a 17.7% stocking level, whereas the number of saplings was 2,330 trees/ha, with a 79.0% stocking level. In germination, the age distribution of saplings ranged from 2001 to 2007, with most belonging to 15-16 years. The development condition of saplings was 10 cm in DBH and 8 m in height. DBH and height were higher as the crown class is more dominant, and this difference was statistically significant in the analysis of variance and Duncan's multiple comparison test (p<0.0001). HD ratio ranged mostly between 80% and 90%, and more than 95% of sapling stems were of high quality, with a straight, unbroken top, non-sweep, and non-diseased stem. On average, the annual height increment of saplings was 21.9 cm at 1 year, 43.3 cm at 5 years, 54.3 cm at 10 years, and 64.3 cm at 15 years. The overall height growth with age increased smoothly. According to the analysis of covariance, the annual height growth by crown class differed significantly. The regression analysis parameters revealed that annual height growth increased with age and dominant crown class.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.4
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• pp.30-40
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• 2021

This study developed quantitative models to estimate the rainfall interception by seven native landscape tree species based on throughfall measurements. The tree species considered in this study were Abies holophylla, Acer palmatum, Ginkgo biloba, Pinus densiflora, Pinus koraiensis, Prunus yedoensis, and Zelkova serrata, which are frequently planted in the Korea. Among these species, 35.8% of the annual precipitation was intercepted by P. koraiensis, 34.1% by A. holophylla, 31.0% by Z. serrata, 27.6% by P. densiflora, 26.9% by G. biloba, 18.6% by A. palmatum, and 18.4% by P. yedoensis. All the quantitative models showed high fitness with r² values of 0.90-0.99. The annual rainfall interception from a tree with DBH of 20 cm were greatest with Z. serrata (5.1 m³/yr), followed by P. koraiensis (4.1 m³/yr), A. holophylla (3.1 m³/yr), G. biloba (2.8 m³/yr), P. densiflora (2.1 m³/yr), P. yedoensis (1.9 m³/yr), and A. palmatum (1.8 m³/yr) in order. Thus, evergreen tree species or those with a relatively high crown density were more effective in intercepting rainfall. In particular, the annual rainfall interception by Z. serrata was the greatest because its crown area, volume, and density were higher than those of the other species. This study pioneers in quantifying annual rainfall interception for landscape tree species in Korea. The study results can be useful for evaluating rainfall interception by landscape trees in urban greenspace design for governments and corporations.

• Journal of Korean Society of Forest Science
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• v.63 no.1
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• pp.35-41
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• 1984

The attempts in this study were made to evaluate the variations in some needle characteristics of Pinus thunbergii between individual trees within population, between populations and between the hypothesized climatic districts. This species occurs naturally along the southern seacoast of Korea penninsula having a relatively mild maritime climate. The followings are the summarized results. The coefficients of variation of the needle volume and needle serration density were generally higher than those of any other traits studied. The significant differences of variations of needle cross section form factor between individual trees within population at 1% level, except only the Young gwang population, were affirmed. In the case of the eastern seacoast district, where the three study populations are included, significances of variation differences were calculated, 5% level at needle serration density and cross section area and 1% Level at needle volume. The very high significant difference of the variations of needle cross section form factor and needle longitudinal form factor were shown between population of the western seacoast district and 5% Level significance at needle volume in the southern seacoast district. The high significant differences between districts in respect to needle cross section form factor and cross section area were calculated. The Duncan's multiple range test showed the dissimilarity of the said characteristics between the hypothesized climatic districts. Summing up the results obtained so far, individual tree and population variations were markedly noted statistically and these may be extended to the silvicultural technology.