• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.6
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• pp.1-11
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• 2022

Recently, climate change has been regarded as a major cause of large-scale forest fires worldwide, and there is concern that more frequent and severe forest fires will occur due to the level of greenhouse gas emissions. In this study, the daily Keetch and Byram Drought Index (KBDI) of the Baekdudaegan in Chungcheong region including Sobaeksan, Songnisan, and Woraksan National Parks were calculated to assess effect of climate change on the forest fire potential- severity of annual maximum KBDI and frequency of high KBDI days. The present (2000~2019) and future KBDI(2021~2040, 2041~2060, 2081~2090) were calculated based on the meteorological observation and the ensemble regional climate model of the SSP1-2.6 and SSP5-8.5 scenarios with a spatial resolution of 1-km provided by Korea Meteorological Administration(KMA). Under the SSP5-8.5 scenario, 6.5℃ increase and 14% precipitation increase are expected at the end of the 21st century. The severity of maximum daily KBDI increases by 48% (+50mm), and the frequency of high KBDI days (> 100 KBDI) increases more than 100 days, which means the high potential for serious forest fires. The analysis results showed that Songnisan National Park has the highest potential for forest fire risk and will continue to be high in intensity and frequency in the future. It is expected that the forest vulnerability of the Baekdudaegan in the Chungcheong region will greatly increase and the difficulty in preventing and suppressing forest fires will increase as the abundance of combustible materials increases along with climate changes.

• Journal of Information Processing Systems
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• v.6 no.3
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• pp.335-346
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• 2010

The present study investigates the difficulty of solving the mathematical problem, namely the DLP (Discrete Logarithm Problem) for ephemeral keys. The DLP is the basis for many public key cryptosystems. The ephemeral keys are used in such systems to ensure security. The DLP defined on a prime field $Z^*_p of random prime is considered in the present study. The most effective method to solve the DLP is the ICM (Index Calculus Method). In the present study, an efficient way of computing the DLP for ephemeral keys by using a new variant of the ICM when the factors of p-1 are known and small is proposed. The ICM has two steps, a pre-computation and an individual logarithm computation. The pre-computation step is to compute the logarithms of a subset of a group and the individual logarithm step is to find the DLP using the precomputed logarithms. Since the ephemeral keys are dynamic and change for every session, once the logarithms of a subset of a group are known, the DLP for the ephemeral key can be obtained using the individual logarithm step. Therefore, an efficient way of solving the individual logarithm step based on the newly proposed precomputation method is presented and the performance is analyzed using a comprehensive set of experiments. The ephemeral keys are also solved by using other methods, which are efficient on random primes, such as the Pohlig-Hellman method, the Van Oorschot method and the traditional individual logarithm step. The results are compared with the newly proposed individual logarithm step of the ICM. Also, the DLP of ephemeral keys used in a popular password key exchange protocol known as Chang and Chang are computed and reported to launch key recovery attack.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.18 no.2
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• pp.96-101
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• 2007

Laryngopharyngeal reflux (LPR) is the retrograde movement of gastric contents into the larynx, pharynx, and upper aero-digestive tract. LPR differs from gastroesophageal reflux in that it is often not associated with heartburn and regurgitation symptoms. Otolaryngological manifestations of acid reflux include a wide range of pharyngeal and laryngeal symptoms. Belafsky et al. developed a useful self-administered tool, the reflux symptom index (RSI), for assessing the degree of LPR symptoms. Patients are asked to use a 0 to 5 point scale to grade the following symptoms: 1) hoarseness or voice problems; 2) throat clearing; 3) excess throat mucus or postnasal drip ; 4) difficulty swallowing; 5) coughing after eating or lying down; 6) breathing difficulties ; 7) troublesome or annoying cough; 8) sensation of something sticking or a lump in the throat; 9) heartburn, chest pain, indigestion or stomach acid coming up. A RSI score greater than 13 is considered abnormal. As there is no validated instrument to document the physical findings and severity of LPR, Belafsky et al. developed an eight-item clinical severity scale for judging laryngoscopic finding, the reflux finding score (RFS). They rated eight LPR-associated findings on a scale from 0 to 4 : subglottic edema, ventricular obliteration, erythema/hyperemia, vocal-fold edema, diffuse laryngeal edema, posterior commissure hypertrophy, granuloma/granulation tissue, and thick endolaryngeal mucus. A RFS score of greater than 7 was found to suggest LPR-associated laryngitis. Although both indices (RSI and RFS) are widely used, there is some controversy about their validity (sensitivity and specificity) and reliability (intra-rater and inter-rater) in LPR diagnosis and treatment. We discuss the validity and reliability of RSI and RFS with literature review.

• Korean Journal of Remote Sensing
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• v.26 no.6
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• pp.653-664
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• 2010

The land surface reflectance is a key parameter influencing the climate near the surface. Therefore, it must be determined with sufficient accuracy for climate change research. In particular, the characteristics of the bidirectional reflectance distribution function (BRDF) when using earth observation system (EOS) are important for normalizing the reflected solar radiation from the earth's surface. Also, wide swath satellites like SPOT/VGT (VEGETATION) permit sufficient angular sampling, but high resolution satellites are impossible to obtain sufficient angular sampling over a pixel during short period because of their narrow swath scanning. This gives a difficulty to BRDF model based reflectance normalization of high resolution satellites. The principal objective of the study is to add BRDF modeling of high resolution satellites and to supply insufficient angular sampling through identifying BRDF components from SPOT/VGT. This study is performed as the preliminary data for apply to high-resolution satellite. The study provides surface parameters by eliminating BRD effect when calculated biophysical index of plant by BRDF model. We use semi-empirical BRDF model to identify the BRD components. This study uses SPOT/VGT satellite data acquired in the S1 (daily) data. Modeled reflectance values show a good agreement with measured reflectance values from SPOT satellite. This study analyzes BRD effect components by using the NDVI(Normalized Difference Vegetation Index) and the angle components such as solar zenith angle, satellite zenith angle and relative azimuth angle. Geometric scattering kernel mainly depends on the azimuth angle variation and volumetric scattering kernel is less dependent on the azimuth angle variation. Also, forest from land cover shows the wider distribution of value than cropland, overall tendency is similar. Forest shows relatively larger value of geometric term ($K_1{\cdot}f_1$) than cropland, When performed comparison between cropland and forest. Angle and NDVI value are closely related.

• The Journal of the Korea Contents Association
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• v.9 no.1
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• pp.407-416
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• 2009

It is evident that a financial feasibility study based on the economic analysis has been theoretically and practically accepted in the aspect of its adequacy. However, it is not easy to apply in the practical business affairs since there exist some difficulties on the economic analysis and the interpretation of the result because of the difficulty of the estimation of the discount rate. This study aims to suggest a method of the financial feasibility study based on the economic analysis. The results of this study are as follows. First, this study can increase the reliance and adequacy of the economic analysis result by suggesting a method of estimating the discount rate by means of the proxy ${\beta}$ method in the practical way. Second, this study can provide the overall frame of the financial feasibility study based on the economic analysis method (namely, Net Present Value Method internal rate of return, profit index method and payback period method)which use discount rate and cash flow. Third, this study can suggest an practical analysis skill required in each step of the financial feasibility study.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.5
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• pp.2045-2049
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• 2014

Background: Functional status is the ability to perform daily activities. Little is known about quality of life and health status of gynaecological cancer patients. The present study therefore aimed to evaluate the functional status of women receiving treatment for gynecological oncological disease while not hospitalised. Materials and Methods: This descriptive study covered 42 patients monitored by the Gynecological Oncology Unit in 2011. Data were collected using the Functional Living Index-Cancer and analysed with the chi square test, independent samples t-test, Mann-Whitney U test, one-way ANOVA test and the Kruskal-Wallis H test. Results: Of the 42 cases, 66.7% had been diagnosed within the previous year and 90.5% were undergoing chemotherapy. The most severe symptoms experienced were pain (35.7%), fatigue-weakness (40.5%) and nausea and vomiting (56.5%). Daily activities where the most difficulty was experienced were housework (28.6%), average pace walking (31.0%), carrying more than 5 kg (28.6%). The mean Functional Living Index score was quite high ($103.5{\pm}24.1$). FLIC-C scale scores did not vary with the educational status, diagnosis duration, and family history of cancer (p>0.05). Conclusions: Evaluation of the functional status of gynecological cancer patients and how they cope with problems should indicate to healthcare professionals what help can be given to maintain quality of life.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.1
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• pp.61-72
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• 2019

With the diversification of research using UAV(Unmanned Aerial Vehicle)s, the possibility of remote sensing research for urban green spaces is increasing. UAVs can be used as an investigation method to monitor the successful construction of the park and the planting of vegetation since its creation. This study was carried out to investigate UAVs utilization of urban green space monitoring in Dosol Square. It was photographed three times on May 21, July 13, and September 16, 2018 using DJI Phantom3 pro, Inspire2, and Parrot Sequoia multispectral camera. Orthographic images were overlaid on the planting plan of the site and the construction results were checked, the change of vitality of the plantation area was analyzed by NDVI(Normalized Difference Vegetation Index) and SAVI(Soil Adjusted Vegetation Index). As a result, it was confirmed that the UAVs are very effective for surveying the view of the urban green space after the construction and recording the results, which can be grasped quantitatively by overlaying the planting plan map. UAVs are more likely to be used in terms of monitoring vegetation vitality. It is interpreted that SAVI is better than NDVI in the green space just after composition. Chionanthus retusus and Pinus strobus were analyzed for their low level of vitality, and partially damaged and their vitality was lowered. In addition, there was difficulty in grass planting area and flower garden due to drainage and summer drought problems. In the future, it is expected that orthoimage and multispectral data using UAVs will be useful in the early vegetation monitoring and management field of urban green spaces.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.1
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• pp.127-136
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• 2002

This papers presents a practical damage detection algorithm based on damage index method that accurately assesses both the location and severity of the localized detriment in a bridge structure using only limited mode shapes. In the algorithm, the ratio of the modal vector sensitivity of an undamaged structure to that of a damaged structure is used as an indicator of damage. However, a difficulty arises when the damaged element is located at a node of mode where the amplitude of medal vector is close to zero, leading the singularity of the ratio (i.e., division-by-zero). This singularity problem is overcome by introducing a parameter denoted a sensitivity filter, a function of mode shape of the structure, in modal vector sensitivity. Using this concept, an improvement can be considerably achieved in the estimation of both degree of severity and location of damage. To verify the proposed algorithm, its numerical implementations are conducted for a simply supported beam and a 2-span continuous beam.

• Journal of The Korean Association For Science Education
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• v.17 no.1
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• pp.65-73
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• 1997

The purpose of this study is to develop a valid and reliable instrument, applicable to high school Earth Science class experiment. In advance of developing items, I was selected 14 inquiry process skills and specified evaluative objectives for each of them to develop scales and criteria for them. I developed 28 evaluation items for 5 experiment subjects among those of high school Earth Science class. The first field trial was performed a sample of 5 high school students, and the second one using a sample of 25 high school students. The results are as follows. (1) The content validity and reliability(Cronbach $\alpha$) of the developed items were 82.7% and .86, respectively, the developed instrument in this study is considered valid and reliable. (2) The average difficulty index was .69 and the discrimination index was .30. (3) Answer sheets based on the reported results were rated 5 teachers and Inter-rater Reliabilitiy and Inter-rater Consistency were analyzed, its indices were .80 and .76, respectively. (4) The developed items show a low coefficient of .45 with TESIS, a set of paper-and-pencil test items developed by Lee, Hang-Ro(1991). That the experiment assessment is solely subject to the rater's viewpoint has been one of the major problems raised concerning the matter. This research, however, shows that a set of more specified scales and criteria for the evaluation will make it more valid, reliable and efficient.

• Journal of Korean society of Dental Hygiene
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• v.10 no.6
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• pp.983-990
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• 2010

Objectives : This study was to investigate the level of oral health, xerostomia, and oral health related activities of daily living(ADL) and the clinical factors influencing oral health related quality of life(OHIP-14) in elderly for visiting healthcare. Methods : Data were obtained from a cross-sectional survey of 106 elderly people(mean age=$77.5{\pm}4.98$). Participants in the study were recruited when they attended the public health center in Cheonan-si. Data were collected by means of a personal interview from July 19 through to August 20, 2010. Oral health related ADL, OHIP-14 and dry mouth was measured by the total 24-items. The data was analysed with t-test, one-way ANOVA, and multiple regression using the SPSS program. Results : Participants had a mean of 13.6 remaining natural teeth, which was significantly with age and perceived oral health. Xerostomia score achieved a mean of 6.39 out of a maximum 12 points. Powerful predictors of OHIP-14 were natural teeth, masticatory difficulty, oral pain, PHP index, perceived oral health, age and living together for the elderly Conclusions : Based on the findings, OHIP-14 has a significantly impact on oral health related ADL. These results suggest that elder people oral health promotion should be developed assessment index which was measured predictors related oral health in the elderly for visiting healthcare.