• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1260-1264
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• 2009

Precipitation time series is a mixture of complicate fluctuation and changes. The monthly precipitation data of 61 stations during 36 years (1973-2008) in Korea are comprehensively analyzed using the EOFs technique and CSEOFs technique respectively. The main motivation for employing this technique in the present study is to investigate the physical processes associated with the evolution of the precipitation from observation data. The twenty-five leading EOF modes account for 98.05% of the total monthly variance, and the first two modes account for 83.68% of total variation. The first mode exhibits traditional spatial pattern with annual cycle of corresponding PC time series and second mode shows strong North South gradient. In CSEOF analysis, the twenty-five leading CSEOF modes account for 98.58% of the total monthly variance, and the first two modes account for 78.69% of total variation, these first two patterns' spatial distribution show monthly spatial variation. The corresponding mode's PC time series reveals the annual cycle on a monthly time scale and long-term fluctuation and first mode's PC time series shows increasing linear trend which represents that spatial and temporal variability of first mode pattern has strengthened. Compared with the EOFs analysis, the CSEOFs analysis preferably exhibits the spatial distribution and temporal evolution characteristics and variability of Korean historical precipitation.

• Journal of Nutrition and Health
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• v.20 no.6
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• pp.442-455
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• 1987

The purpose of the study were to assist foodservice managers in complex decision making by utilizing computerized cost accounting system and to relieve managers from repetitive and routine tasks so that more adequate patient care and consultation can be provided. The scope of the computer-assisted cost accounting system consists of budget, menu planning, purchasing, inventory, cost control and financial reporting. The content of the computerized system are summarized as follows ; 1) For budgeting monthly income was estimated by calculating unit cost of each meal and forecasting serving numbers. The actual serving numbers for patients and employees were totaled everyday, and utilized as the basic data base for estimating income and planning menu. The monthly lists of meal sensus were generated. 2) for menu planning concersion factors were computed based on the standarized recipe for 50 servings. Daily menus for patients and employees which include total amounts of each ingredient and cost analyzed information were generated. 3) Daily and monthly purchasing report for each food item classified by patient and employee meals were generated. 4) Inventory transactions such as recipts and issues were totalized daily for each stocked item, and monthly inventory reports were generated. 5) Cost analysis reports for each menu item were generated into two ways based on the budget coat as well as the purchasing cost. 6) Editing new recipes and updating food costs change to the data base were carried out. 7) Financial reports were generated monthly, first-half and second-half of the year, and yearly basis.

• Journal of Industrial Technology
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• v.3
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• pp.69-74
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• 1983

For the determination of a reservoir capacity Rippl's mass-curve method has long been used with the past river flow data assuming the same flow records will be repeated in the future. This study aims to find out a better method for determining the reservoir capacity by employing the analytical theory based on the stochastic process. For the present study the synthetic generation methods of Thomas-Fiering type was used to synthetically generate 50 years of monthly river inflows to three single-purpose reservoirs and three multi-purpose reservoirs. The generated sequences of monthly flows were analyzed based on the range concept. With the optimum operation rule of the reservoirs as the one which maximizes the water-use downstream the waterrelease from the reservoir was determined and with due consideration to the mean inflows and the range of monthly flows the required reservoirs capacity was stochastically determined. It was possible to repersent the so-determined reservoir capacity in terms of the mean monthly inflows and the number of subseries in the determination of ranges. It is suggested that the result obtained in this study would be applied to approximately estimate, in the stage of preliminary design, the required capacity of a reservoir in question with the limited information such as the mean monthly inflow and the period of reservoir operation.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.523-523
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• 2000

We have developed a method to build time series prediction models by Genetic Programming (GP). Our proposed CP includes two new techniques. One is the parameter optimization algorithm, and the other is the new mutation operator. In this paper, the sunspot prediction experiment by our proposed CP was performed. The sunspot prediction is good benchmark, because many researchers have predicted them with various kinds of models. We make three experiments. The first is to compare our proposed method with the conventional methods. The second is to investigate about the relation between a model-building period and prediction precision. In the first and the second experiments, the long-term data of annual sunspots are used. The third is to try the prediction using monthly sunspots. The annual sunspots are a mean of the monthly sunspots. The behaviors of the monthly sunspot cycles in tile annual sunspot data become invisible. In the long-term data of the monthly sunspots, the behavior appears and is complicated. We estimate that the monthly sunspot prediction is more difficult than the annual sunspot prediction. The usefulness of our method in time series prediction is verified by these experiments.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.387-392
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• 1998

To establish a monthly data collection planning for the Ocean Scanning Multispectral Imager (OSMI), we have examined the global patterns of three impacting factors: pigment concentration, cloud cover, and sun glint. Other than satellite mission constraints (e.g., duty cycle), these three factors are considered critical for the OSMI data collection. The Nimbus-7 Coastal Zone Color Scanner (CZCS) monthly mean products and the International Satellite Cloud Climatology Project (ISCCP) monthly mean products (C2) were used for the analysis of pigment concentration and cloud cover distributions, respectively. And the monthly simulated patterns of sun glint were produced by performing the OSMI orbit prediction and the calculation of sun glint radiances at the top-of-atmosphere (TOA). Using monthly statistics (mean and/or standard deviation) of each factor in the above for a given 10$^{\circ}$ latitude by 10$^{\circ}$ longitude grid, we generated the priority map for each month. The priority maps of three factors for each month were subsequently superimposed to visualize the impact of three factors in all. The initial results illustrated that a large part of oceans in the summer hemisphere was classified into the low priority regions because of seasonal changes of clouds and sun illumination. Sensitivity tests were performed to see how cloud cover and sun glint affect the priority determined by pigment concentration distributions, and consequently to minimize their seasonal effects upon the data collection planning.

• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.4
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• pp.99-108
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• 1982

This thesis aims to estimate the rainfall runoff from paddy field in a small watershed during irrigation period. When the data observed at the proposed site are not available, the Monthly Runoff Equation of Korean Rivers which was derived from data observed under the following assumptions is used to study the water balance. a. Monthly base flow was assumed as 10. 2mm even if these is no mouthly rainmfall. b. Monthly comsumption of rainfall was ranged from 100 to 2OOmm without relation to the rainfall depth. However, the small watershed which consists mainly of paddy fields encounters severe droughts and accordingly the baseflow is negligible. Under the circumstances the author has developed the following equation called "Flood Irrigation Method for Rainfall Runoff "taking account of the evapotranspiration, precipitation, seepage, less of transportation, etc. R= __ A 7000(1 +F) -5n(n+1)+ (n+1)(Pr-S-Et)] where: R: runoff (ha-m) A: catchment area (ha) F: coefficient of loss (o.o-0. 20) Pr: rainfall (mm) S: seepage Er: evapotranspiration (mm) To verify the above equation, the annual runoff ratio for 28 years was estimated using the Monthly Runoff Equation of Korean Rivers the Flood Irrigation Method and the Complex Hydrograph Method based on meteorological data observed in the Dae Eyeog project area, and comparison was made with data observed in the Han River basin. Consequently, the auther has concluded that the Flood Irrigation Method is more consi- stent with the Complex Hydrograph Method and data observed than the Monthly Runoff Equation of Korean Rivers.

• The Korean Journal of Ecology
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• v.18 no.1
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• pp.157-177
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• 1995

Monthly changes in communities of benthic macroinvertebrates collected in the Suyong and Soktae stream of the Suyong river were investigated from September 1993 to August 1994. The total number of species collected during the study period ranged from seven to seventy six species according to pollution levels at the study sites. Monthly changes in species richness appeared differently in different taxonomic assemblages. In chironomids differences in species richness responding to different levels of saprobity were shown consistently as time proceeded. In Ephemeroptera species richness at the relatively clean sites responded sensitively to slight enrichment. In connection with species richness the monthly changes in densities in taxonomic assemblages also appeared to effectively represent environmental impacts. Species diversity generally represented the pollution status also, however the monthly variations at the study sites appeared to be relatively high. The clustering analysis showed that the communities collected at polluted sites were grouped closely, and the communities collected at the relatively clean sites were clustered to the same stream although the degree of community association was low, Through the Principal Component Analysis, the impact of Pollution was reflected in a great degree in overall community variations.

• Water for future
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• v.24 no.4
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• pp.59-66
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• 1991

Abstract The purpose of the synthetic of monthly river flows based on the short-term observed data by means of multivariate stochastic models is to provide abundunt input data to the water resources systems of which the system performance and operation policy are to be determined beforehand. In this study, multivariate Thomas-Fiering and Matalas models for synthetic generation based on stream flows in neihboring basin were employed to check if it can be applide in the modeling of monthly flows. Statistical parameters estimated by Method of Moment and Fourier Series Analysis respectively were reproduced for statistical features. For comparisons the statistical parameters of the generated monthly flow by each model were compared with those of the observed monthly flows. Results of this study suggest that the application of Matalas model for synthetic generation of monthly river flows can be adapted.

• Journal of Digital Convergence
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• v.19 no.8
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• pp.337-343
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• 2021

This study researched the user experience of the monthly magazine subscription service, focusing on design students and designers. The revenue of magazine industry has been declined since 2012 and some magazines stop publishing or cease to publish. That is why this studied the user experience of magazine subscription services of monthly to increase magazine sales revenue, the largest portion of whole revenue. A survey and in-depth interviews with subscribers and non-subscribers was conducted to suggest improvements for the monthly . Since this study focused on user experience of magazine subscription, it could be a future reference for studying magazine subscription service.

• Journal of Astronomy and Space Sciences
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• v.38 no.1
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• pp.23-29
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• 2021

Utilizing a new version of the sunspot number and group sunspot number dataset available since 2015, we have statistically studied the relationship between solar activity parameters describing solar cycles and the slope of the linear relationship between the monthly sunspot numbers and the monthly number of active days in percentage (AD). As an effort of evaluating possibilities in use of the number of active days to predict solar activity, it is worthwhile to revisit and extend the analysis performed earlier. In calculating the Pearson's linear correlation coefficient r, the Spearman's rank-order correlation coefficient rs, and the Kendall's τ coefficient with the rejection probability, we have calculated the slope for a given solar cycle in three different ways, namely, by counting the spotless day that occurred during the ascending phase and the descending phase of the solar cycle separately, and during the period corresponding to solar minimum ± 2 years as well. We have found that the maximum solar sunspot number of a given solar cycle and the duration of the ascending phase are hardly correlated with the slope of a linear function of the monthly sunspot numbers and AD. On the other hand, the duration of a solar cycle is found to be marginally correlated with the slope with the rejection probabilities less than a couple of percent. We have also attempted to compare the relation of the monthly sunspot numbers with AD for the even and odd solar cycles. It is inconclusive, however, that the slopes of the linear relationship between the monthly group numbers and AD are subject to the even and odd solar cycles.