• Korean journal of applied entomology
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• v.25 no.4 s.69
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• pp.221-228
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• 1986

An empirical model to predict initial disease occurrence and subsequent progress of Alternaria leaf spot was constructed based on the modified degree day temperature and frequency of rainfall in three years field experiments. Climatic factors were analized 10-day bases, beginning April 20 to the end of August, and were used as variables for model construction. Cumulative degree portion (CDP) that is over $10^{\circ}C$ in the daily average temperature was used as a parameter to determine the relationship between temperature and initial disease occurrence. Around one hundred and sixty of CDP was needed to initiate disease incidence. This value was considered as temperature threshhold. After reaching 160 CDP, time of initial occurrence was determined by frequency of rainfall. At least four times of rainfall were necessary to be accumulated for initial occurrence of the disease after passing temperature threshhold. Disease progress after initial incidence generally followed the pattern of frequency of rainfall accumulated in those periods. Apparent infection rate (r) in the general differential equation dx/dt=xr(1-x) for individual epidemics when x is disease proportion and t is time, was a linear function of accumulation rate of rainfall frequency (Rc) and was able to be directly estimated based on the equation r=1.06Rc-0.11($R^2=0.993$). Disease severity (x) after t time could be predicted using exponential equation $[x/(1-x)]=[x_0/(1-x)]e^{(b_0+b_1R_c)t}$ derived from the differential equation, when $x_0$ is initial disease, $b_0\;and\;b_1$ are constants. There was a significant linear relationship between disease progress and cumulative number of air-borne conidia of Alternaria mali. When the cumulative number of air-borne conidia was used as an independent variable to predict disease severity, accuracy of prediction was poor with $R^2=0.3328$.

• Journal of Intelligence and Information Systems
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• v.20 no.2
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• pp.59-71
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• 2014

System trading is becoming more popular among Korean traders recently. System traders use automatic order systems based on the system generated buy and sell signals. These signals are generated from the predetermined entry and exit rules that were coded by system traders. Most researches on system trading have focused on designing profitable entry and exit rules using technical indicators. However, market conditions, strategy characteristics, and money management also have influences on the profitability of the system trading. Unexpected price deviations from the predetermined trading rules can incur large losses to system traders. Therefore, most professional traders use strategy portfolios rather than only one strategy. Building a good strategy portfolio is important because trading performance depends on strategy portfolios. Despite of the importance of designing strategy portfolio, rule of thumb methods have been used to select trading strategies. In this study, we propose a SVM-based strategy portfolio management system. SVM were introduced by Vapnik and is known to be effective for data mining area. It can build good portfolios within a very short period of time. Since SVM minimizes structural risks, it is best suitable for the futures trading market in which prices do not move exactly the same as the past. Our system trading strategies include moving-average cross system, MACD cross system, trend-following system, buy dips and sell rallies system, DMI system, Keltner channel system, Bollinger Bands system, and Fibonacci system. These strategies are well known and frequently being used by many professional traders. We program these strategies for generating automated system signals for entry and exit. We propose SVM-based strategies selection system and portfolio construction and order routing system. Strategies selection system is a portfolio training system. It generates training data and makes SVM model using optimal portfolio. We make $m{\times}n$ data matrix by dividing KOSPI 200 index futures data with a same period. Optimal strategy portfolio is derived from analyzing each strategy performance. SVM model is generated based on this data and optimal strategy portfolio. We use 80% of the data for training and the remaining 20% is used for testing the strategy. For training, we select two strategies which show the highest profit in the next day. Selection method 1 selects two strategies and method 2 selects maximum two strategies which show profit more than 0.1 point. We use one-against-all method which has fast processing time. We analyse the daily data of KOSPI 200 index futures contracts from January 1990 to November 2011. Price change rates for 50 days are used as SVM input data. The training period is from January 1990 to March 2007 and the test period is from March 2007 to November 2011. We suggest three benchmark strategies portfolio. BM1 holds two contracts of KOSPI 200 index futures for testing period. BM2 is constructed as two strategies which show the largest cumulative profit during 30 days before testing starts. BM3 has two strategies which show best profits during testing period. Trading cost include brokerage commission cost and slippage cost. The proposed strategy portfolio management system shows profit more than double of the benchmark portfolios. BM1 shows 103.44 point profit, BM2 shows 488.61 point profit, and BM3 shows 502.41 point profit after deducting trading cost. The best benchmark is the portfolio of the two best profit strategies during the test period. The proposed system 1 shows 706.22 point profit and proposed system 2 shows 768.95 point profit after deducting trading cost. The equity curves for the entire period show stable pattern. With higher profit, this suggests a good trading direction for system traders. We can make more stable and more profitable portfolios if we add money management module to the system.

• Journal of The Korean Society of Grassland and Forage Science
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• v.12 no.2
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• pp.77-84
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• 1992

This experiment was designed to gain information on factors affecting stubble death of orchardgrass (Dactylis glomerata L.) during the first rainy season. According to the experimental plan, the effects of sowing methods, drainages and cutting dates on the stubble carbohydrate content of orchardgrass, available soil moisture content of experimental plots, temperatures at the ground level and in the soil, and relative light intensity and humidity at the base of orchardgrass canopy were measured during the rainy season. The carbohydrate content of orchardgrass was sharply decreased to 2.9 % at 3rd day after cutting in the plots cut before rainy season and a gradural recovery was noted following the sharp reduction, but in the plots cut after rainy season, orchardgrass showed 5.5% of carbohydrate content before cutting and 3.0% at the 3rd day after cutting. The same pattern in both carbohydrate reduction and recovery was found between two cutting treatments. The available soil moisture content in the plots cut before rainy season was slightly higher than that in the plots cut after rainy season. But after the rainy season, the available soil moisture content in the plots cut after rainy season was higher than that in the plots cut before rainy season. Soil temperature at lOcm depths in the plots cut before rainy season was higher than that in the plots cut after rainy season. Daily maximum air temperature at the ground level in the plots cut before rainy season was higher than that in the plots cut after rainy season and changeable. Relative humidity at the ground level was below 70% in the plots cut before rainy season, but 75 to 90 % was observed in the plots cut after rainy season. Relative light intensity at the ground level in the plots cut before rainy season was much higher, recorded 50 to 90 %, than that in the plots cut after rainy season showing less than 10%. The results of this study suggest that the stubble death of orchardgrass during the rainy season is due to plant diseases influenced by a decrease of light penetration and increase of relative humidity at the base of the grass canopy.

• Korean Journal of Agricultural and Forest Meteorology
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• v.10 no.4
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• pp.121-131
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• 2008

This study was conducted to delineate temporal and spatial patterns of potential risk of cold injury by combining the short-term cold hardiness of Campbell Early grapevine and the IPCC projected climate winter season minimum temperature at a landscape scale. Gridded data sets of daily maximum and minimum temperature with a 270m cell spacing ("High Definition Digital Temperature Map", HD-DTM) were prepared for the current climatological normal year (1971-2000) based on observations at the 56 Korea Meteorological Administration (KMA) stations using a geospatial interpolation scheme for correcting land surface effects (e.g., land use, topography, and elevation). The same procedure was applied to the official temperature projection dataset covering South Korea (under the auspices of the IPCC-SRES A2 and A1B scenarios) for 2071-2100. The dormancy depth model was run with the gridded datasets to estimate the geographical pattern of any changes in the short-term cold hardiness of Campbell Early across South Korea for the current and future normal years (1971-2000 and 2071-2100). We combined this result with the projected mean annual minimum temperature for each period to obtain the potential risk of cold injury. Results showed that both the land areas with the normal cold-hardiness (-150 and below for dormancy depth) and those with the sub-threshold temperature for freezing damage ($-15^{\circ}C$ and below) will decrease in 2071-2100, reducing the freezing risk. Although more land area will encounter less risk in the future, the land area with higher risk (>70%) will expand from 14% at the current normal year to 23 (A1B) ${\sim}5%$ (A2) in the future. Our method can be applied to other deciduous fruit trees for delineating geographical shift of cold-hardiness zone under the projected climate change in the future, thereby providing valuable information for adaptation strategy in fruit industry.

• Journal of Nutrition and Health
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• v.46 no.2
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• pp.177-185
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• 2013

The purpose of this study was to analyze the nutritional status of Chinese female college students in Korea, and to investigate changes in their dietary behavior after residing in Korea. The subjects included 114 Chinese female college students currently studying in Korea. General characteristics and dietary behaviors before and after residing in Korea were investigated. Daily nutrients and food intake were assessed using a one-day 24-hour recall. Consumption of most nutrients, namely calcium, iron, zinc, vitamin $B_2$, vitamin C, and folate was estimated to fall below the EAR for the Korean population. The proportions of subjects whose intake were estimated below the EAR for folate, calcium, vitamin $B_2$, iron, zinc, and vitamin C were 93.0%, 71.9%, 66.7%, 65.8%, 65.8%, and 63.2%, respectively. In the current study, the dietary behavior scores fell significantly after Chinese students immigrated to Korea (p < 0.001); increased frequency of meal skipping, less consumption of fruits and vegetables, irregular meal pattern, and imbalanced diet were some of the significant changes among Chinese students before and after residing in Korea. In addition, consumption of most nutrients, including dietary fiber, vitamin A, vitamin B group, vitamin C, and folate in the Worsened Group was significantly lower, compared with the No Change Group (p < 0.05). According to the changes in dietary behaviors, consumption of most nutrients, including dietary fiber, vitamin A, vitamin B group, vitamin C, and folate in the Worsened Group was significantly lower than in the No Change Group (p < 0.05). In conclusion, these results indicated that Chinese students practiced more unhealthy dietary behaviors after residing in Korea and Chinese students residing in Korea showed poor nutrient-based diet quality. Conduct of a follow-up study using blood profile tests is needed in order to assess the nutritional status of Chinese students. These results would be used in planning of a nutritional surveillance program for Chinese students.

• Journal of the Korean earth science society
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• v.42 no.5
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• pp.479-495
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• 2021

This study investigates the synoptic (patterns of southern highs, northern lows, and lows rapidly developed by tropopause folding), thermodynamic, and kinematic characteristics of a strong wind that occurred in the Yeongdong region of South Korea on March 18-20, 2020. To do so, we analyzed data from an automatic weather station (AWS), weather charts, the European Centre for Medium-range Weather Forecasts (ECMWF) reanalysis, rawinsonde, and windprofiler radars. The daily maximum instantaneous wind speed, exceeding 20 m s^-1, was observed at five weather stations during the analysis period. The strongest instantaneous wind speed (27.7 m s^-1) appeared in the Daegwallyeong area. According to the analysis of weather charts, along with the arrangement of the north-south low-pressure line, the isobars were moved to the Yeongdong area. It showed a sine wave shape, and a strong wind developed owing to the strong pressure gradient. On March 19, in the northern part of the Korean Peninsula, with a drop in atmospheric pressure of 19 hPa or more within one day, a continuous strong wind was developed by the synoptic structure of the developing polar low. In the adiabatic chart observed in Bukgangneung, the altitude of the inversion layer was located at an altitude of approximately 1-3 km above the mountaintop, along with the maximum wind speed. We confirmed that this is consistent with the results of the vertical wind field analysis of the rawinsonde and windprofiler data. In particular, based on the thermodynamic and kinematic vertical analyses, we suggest that strong winds due to the vertical gradient of potential temperature in the lower layer and the development of potential vorticity due to tropopause folding play a significant role in the occurrence of strong winds in the Yeongdong region.

• Journal of Family Resource Management and Policy Review
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• v.25 no.2
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• pp.53-78
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• 2021

The concept of household labor is composed of housework and family care, and it provides a framework for understanding daily life from the perspective of work-life balance. The purpose of this study was to investigate the household labor time of Korean adults by gender and generation over the last 20 years. Data was taken from the five Statistics Korea Life Time Surveys from 1999 (t1) to 2019 (t5) (n=69,196). The major results are as follows: first, gender and generation were found to have a significant relationship with household labor time over the study period. Household labor time for females was 3.8 times that of males in 1999, but females' household labor time decreased over the next 20 years while males' increased, including both housework and family care. The female participation rate in household work also remained steady, while that for males increased. Second, in the younger and middle generations, a similar gender and generational pattern was seen. Third, in the older generation, household time and participation rates for both females and males increased. The family welfare policy and theoretical implications of these results are discussed.

• The Korean Journal of Archival Studies
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• no.10
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• pp.276-322
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• 2004

Historical interest in China in 1930s has been mostly focused on political characteristic of the National Government(國民政府) which was established by the KMT(中國國民黨) as a result of national unification. It is certain that China had a chance to construct a modern country by the establishment of the very unified revolutionary government. But, it was the time of expanding national crises that threatened the existence of the country such as the Manchurian Incident and the Chinese-Japanese War as well as the chaos of the domestic situation, too. So it has a good reason to examine the characteristic and pattern of the response of the political powers of those days. But, as shown in the recent studies, the manifestation method of political power by the revolutionary regime catches our attention through the understanding of internal operating system. Though this writing started from the fact that the Nationalist Government executed the administrative reform which aimed at "administrative efficiency" in the middle of 1930s, but it put stress on the seriousness of the problem and its solution rather than political background or results. "Committee on Administrative Efficiency(行政效率委員會)", the center of administrative reform movement which was established in 1934, examined the plan to execute the reform through legislation by the Executive Council(行政院) on the basis of the results of relevant studies. They claimed that the construction of a modern country should be performed by not political revolution anymore but by gradual improvement and daily reform, and that the operation of the government should become modern, scientific and efficient. There were many fields of administrative reform subjects, but especially, the field of records and archives adminstration(文書檔案行政) was studied intensively from the initial stage because that subject had already been discussed intensively. They recognized that records and archives were the basic tool of work performance and general activity but an inefficient field in spite of many input staff members, and most of all, archival reform bring about less conflicts than the fields of finance, organization and personnel. When it comes to the field of records adminstration, the key subjects that records should be written simply, the process of record treatment should be clear and the delay of that should be prevented were already presented in a records administrative meeting in 1922. That is, the unified law about record management was not established, so each government organization followed a conventional custom or performed independent improvement. It was through the other records administrative workshop of the Nationalist Government in 1933 when the new trend was appeared as the unified system improvement. They decided to unify the format of official records, to use marker and section, to unify the registration of receipt records and dispatch records and to strengthen the examination of records treatment. But, the method of records treatment was not unified yet, so the key point of records administrative reform was to establish a unified and standard record management system for preventing repetition by simplifying the treatment procedure and for intensive treatment by exclusive organizations. From the foundation of the Republic of China to 1930s, there was not big change in the field of archives administration, and archives management methods were prescribed differently even in the same section as well as same department. Therefore, the point at issue was to centralize scattered management systems that were performed in each section, to establish unified standard about filing and retention period allowance and to improve searching system through classification and proper number allowance. Especially, the problem was that each number system and classification system bring about different result due to dual operation of record registration and archives registration, and that strict management through mutual contrast, searching and application are impossible. Besides, various problems such as filing tools, arrangement method, preservation facilities & equipment, lending service and use method were raised also. In the process this study for the system improvement of records and archives management, they recognized that records and archives are the identical thing and reached to create a successive management method of records and archives called "Records and Archives Chain Management Method(文書檔案連鎖法)" as a potential alternative. Several principles that records and archives management should be performed unitedly in each organization by the general record recipient section and the general archives section under the principle of task centralization, a consistent classification system should be used by classification method decided in advance according to organizational constitution and work functions and an identical number system should be used in the process of record management stage and archive management stage by using a card-type register were established. Though, this "Records and Archives Chain Management Method" was developed to the stage of test application in several organizations, but it was not adopted as a regular system and discontinued. That was because the administrative reform of the Nationalist Government was discontinued by the outbreak of the Chinese-Japanese War. Even though the administrative reform in the middle of 1930s didn't produce practical results but merely an experimentation, it was verified that the reform against tradition and custom conducted by the Nationalist Government that aimed for the construction of a modern country was not only a field of politics, but on the other hand, the weak basis of the government operation became the obstacle to the realization of the political power of the revolutionary regime. Though the subject of records and archives administrative reform was postponed to the future, it should be understood that the consciousness of modern records and archives administration and overall studies began through this examination of administrative reform.

• Journal of Nutrition and Health
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• v.52 no.1
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• pp.36-46
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• 2019

Purpose: This study evaluated amounts of physical activity and sedentary behavior patterns in older adults using an accelerometer and physical activity diary. Methods: Forty-nine older adults (male 26, female 23) participated in this study. They wore a triaxial accelerometer (ActiGraph wGT3X-BT) for one week and wrote a physical activity diary concurrently for three days. Amounts of physical activity, sedentary behavior patterns, and percentage of meeting the World health organization (WHO) physical activity guidelines were analyzed using an accelerometer. In addition, the contents recorded in the physical activity diary were reclassified to 18 levels and the average daily times spent on each level and physical activity level (PAL) were calculated. Results: The subjects were sitting more than half of the day except for bedtime and shower time (59.2%). The numbers of prolonged ${\geq}30$, 40 minutes sedentary bouts were significantly higher in males ($3.10{\pm}1.34$, $1.78{\pm}1.09$, respectively) than in females ($2.34{\pm}1.22$, $1.32{\pm}1.07$, respectively) and the number of breaks per sedentary hour was significantly less in males ($5.74{\pm}0.89$) than in females ($6.44{\pm}0.71$). Among the activities corresponding to sedentary behavior surveyed by the physical activity diary, only the amount of time spent 'resting, speaking and watching TV' showed a significant correlation with the sedentary behavior pattern measured by the accelerometer. The persistence of sedentary behavior was interrupted primarily when low intensity activity was performed. Only 22.4% of the subjects met WHO physical activity guidelines. Conclusion: Based on these results, the physical activity guidelines for older adults should be developed that reflects the appropriate strength, including low activity level and maintenance time of moderate to vigorous physical activity.

• Korean Journal of Psychosomatic Medicine
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• v.26 no.2
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• pp.94-101
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• 2018

Objectives : The purpose of this study is to investigate the change pattern and the leading factors of delirium in the palliative ward from 2 weeks before to the end of life. Methods : From October 2015 to August 2017, a retrospective chart review was conducted on the final 180 patients of 207 patients with terminal cancer patients at the Inha University Hospital. Clinical records were collected during palliative care hospitalization. Patients were diagnosed with three subtypes of delirium through the Richmond Agitation Sedation Scale and the Nursing Delirium Screening Scale, which were evaluated daily. Results : The prevalence of delirium 13 days before death was 46%, of which 18.3% were hyperactive subtypes, 13.8% were hypoactive subtypes, and mixed subtypes were 13.8%. And hyperactive delirium gradually decreased with the approach to the end of the day, and the mixed subtype gradually increased until 4 days before the end of life. Of the patients, the day before death, 86.9% were diagnosed with delirium. In multivariate analysis, hematologic malignancy was associated with a lower rate of delirium at the end of life than gastrointestinal cancer. Overweight was associated with hyperactive, mixed, and hypoactive delirium. Conclusions : Most palliative care patients experienced delirium at the end of life. Overweight was considered as a protective factor that reduced the all subtypes of delirium at the end of life. Further prospective studies are needed to reveal the prevalence of terminal delirium, and their risk factors.