• Title/Summary/Keyword: Forecast accuracy

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Comparison of Marine Insolation Estimating Methods in the Adriatic Sea

  • Byun, Do-Seong;Pinardi, Nadia
    • Ocean Science Journal
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    • v.42 no.4
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    • pp.211-222
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    • 2007
  • We compare insolation results calculated from two well-known empirical formulas (Socket and Beaudry's SB73 formula and the original Smithsonian (SMS) formula) and a radiative transfer model using input data predicted from meteorological weather-forecast models, and review the accuracy of each method. Comparison of annual mean daily irradiance values for clear-sky conditions between the two formulas shows that, relative to the SMS, the SB73 underestimates spring values by 9 W $m^{-2}$ in the northern Adriatic Sea, although overall there is a good agreement between the annual results calculated with the two formulas. We also elucidate the effect on SMS of changing the 'Sun-Earth distance factor (f)', a parameter which is commonly assumed to be constant in the oceanographic context. Results show that the mean daily solar radiation for clear-sky conditions in the northern Adriatic Sea can be reduced as much as 12 W $m^{-2}$ during summer due to a decrease in the f value. Lastly, surface irradiance values calculated from a simple radiative transfer model (GM02) for clear-sky conditions are compared to those from SB73 and SMS. Comparison with iu situ data in the northern Adriatic Sea shows that the GM02 estimate gives more realistic surface irradiance values than SMS, particularly during summer. Additionally, irradiance values calculated by GM02 using the buoy meteorological fields and ECMWF (The European Centre for Medium Range Weather Forecasts) meteorological data show the suitability of the ECMWF data usage. Through tests of GM02 sensitivity to key regional meteorological factors, we explore the main factors contributing significantly to a reduction in summertime solar irradiance in the Adriatic Sea.

Preliminary Research for Development of Instrument for Cold-Heat & Deficiency-Excess Pattern Identification of Dementia (치매(痴呆)의 한열허실(寒熱虛實) 변증(辨證)을 위한 지표 문항 개발에 관한 기초 연구)

  • Heo, Eun Jung;Kang, Hyung Won;Jeon, Won Kyung
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.27 no.5
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    • pp.553-562
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    • 2013
  • This study was performed to develop cold-heat and deficiency-excess pattern identification for dementia, as well as for standard Korean medicine diagnosis and treatment. Five experts comprised of 4 neuropsychiatrists of Korean medicine and 1 statistician to develop cold-heat and deficiency-excess pattern identification for dementia. We searched studies about pattern identification and selected 507 articles using Oasis search terms provided by the KIOM. As a result, 10 pattern identification research study were recruited. Moreover, we analyzed neuropsychological assessments for dementia that evaluate Behavioral and Psychological Symptoms of Dementia (BPSD) and cognitive function using experts conferences and we selected neuropsychological instruments using pattern identification. Six cold patterns, six heat patterns, ten deficiency patterns, and four excess patterns were identified according to the cold-heat and deficiency-excess pattern identification of dementia. We selected the Caregiver-Administered Neuropsychiatric Inventory and the Korean Mini-Mental State Examination as neuropsychological assessments of dementia, which examine behavioral symptoms and cognitive function, suspectively. We formed positive and negative correlation between Korean medicine pattern identification and neuropsychological assessments for dementia. We developed and suggested a forecast module of pattern identification for dementia. But, it is necessary to perform additional clinical trials to verify its validity and accuracy.

Establishment and Application of Neuro-Fuzzy Real-Time Flood Forecasting Model by Linking Takagi-Sugeno Inference with Neural Network (I) : Selection of Optimal Input Data Combinations (Takagi-Sugeno 추론기법과 신경망을 연계한 뉴로-퍼지 홍수예측 모형의 구축 및 적용 (I) : 최적 입력자료 조합의 선정)

  • Choi, Seung-Yong;Kim, Byung-Hyun;Han, Kun-Yeun
    • Journal of Korea Water Resources Association
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    • v.44 no.7
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    • pp.523-536
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    • 2011
  • The objective of this study is to develop the data driven model for the flood forecasting that are improved the problems of the existing hydrological model for flood forecasting in medium and small streams. Neuro-Fuzzy flood forecasting model which linked the Takagi-Sugeno fuzzy inference theory with neural network, that can forecast flood only by using the rainfall and flood level and discharge data without using lots of physical data that are necessary in existing hydrological rainfall-runoff model is established. The accuracy of flood forecasting using this model is determined by temporal distribution and number of used rainfall and water level as input data. So first of all, the various combinations of input data were constructed by using rainfall and water level to select optimal input data combination for applying Neuro-Fuzzy flood forecasting model. The forecasting results of each combination are compared and optimal input data combination for real-time flood forecasting is determined.

Development of Hydrological Shared Vision Model for Conflict Mediation of Dam Construction (댐 건설 갈등 조정을 위한 수문학적 공영시각모형의 개발)

  • Jung, Ha Ok;Han, Jae Ik;Park, Sang Woo
    • Journal of Korea Water Resources Association
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    • v.45 no.10
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    • pp.1009-1022
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    • 2012
  • This study approach the conflict in the process of promoting Dam construction plan from a hydrological method and comprehend the cause of conflict on conservation and flood collect all interested parties direct involvement and develop Shared Vision Model (SVM) to plan simulation and result. We forecast water for living, industrial water and agricultural water in each administrative district on conservation and simulate promptly in case that each structural alternative is formed and suggest water level deduction effect and change of area on watted surface and damage and organize the system to draw and agreement through exchanging mutual opinion. Also, it considered to contribute meditation and soften of conflict by securing accuracy of releasing information and trust of the result.

A Decision Support Model for Sustainable Collaboration Level on Supply Chain Management using Support Vector Machines (Support Vector Machines을 이용한 공급사슬관리의 지속적 협업 수준에 대한 의사결정모델)

  • Lim, Se-Hun
    • Journal of Distribution Research
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    • v.10 no.3
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    • pp.1-14
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    • 2005
  • It is important to control performance and a Sustainable Collaboration (SC) for the successful Supply Chain Management (SCM). This research developed a control model which analyzed SCM performances based on a Balanced Scorecard (ESC) and an SC using Support Vector Machine (SVM). 108 specialists of an SCM completed the questionnaires. We analyzed experimental data set using SVM. This research compared the forecasting accuracy of an SCMSC through four types of SVM kernels: (1) linear, (2) polynomial (3) Radial Basis Function (REF), and (4) sigmoid kernel (linear > RBF > Sigmoid > Polynomial). Then, this study compares the prediction performance of SVM linear kernel with Artificial Neural Network. (ANN). The research findings show that using SVM linear kernel to forecast an SCMSC is the most outstanding. Thus SVM linear kernel provides a promising alternative to an SC control level. A company which pursues an SCM can use the information of an SC in the SVM model.

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A Development of Real-time Flood Forecasting System for U-City (Ubiquitous 환경의 U-City 홍수예측시스템 개발)

  • Kim, Hyung-Woo
    • 한국정보통신설비학회:학술대회논문집
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    • 2007.08a
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    • pp.181-184
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    • 2007
  • Up to now, a lot of houses, roads and other urban facilities have been damaged by natural disasters such as flash floods and landslides. It is reported that the size and frequency of disasters are growing greatly due to global warming. In order to mitigate such disaster, flood forecasting and alerting systems have been developed for the Han river, Geum river, Nak-dong river and Young-san river. These systems, however, do not help small municipal departments cope with the threat of flood. In this study, a real-time urban flood forecasting service (U-FFS) is developed for ubiquitous computing city which includes small river basins. A test bed is deployed at Tan-cheon in Gyeonggido to verify U-FFS. Wireless sensors such as rainfall gauge and water lever gauge are installed to develop hydrologic forecasting model and CCTV camera systems are also incorporated to capture high definition images of river basins. U-FFS is based on the ANFIS (Adaptive Neuro-Fuzzy Inference System) that is data-driven model and is characterized by its accuracy and adaptability. It is found that U-FFS can forecast the water level of outlet of river basin and provide real-time data through internet during heavy rain. It is revealed that U-FFS can predict the water level of 30 minutes and 1 hour later very accurately. Unlike other hydrologic forecasting model, this newly developed U-FFS has advantages such as its applicability and feasibility. Furthermore, it is expected that U-FFS presented in this study can be applied to ubiquitous computing city (U-City) and/or other cities which have suffered from flood damage for a long time.

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Forecasting Short-Term KOSPI using Wavelet Transforms and Fuzzy Neural Network (웨이블릿 변환과 퍼지 신경망을 이용한 단기 KOSPI 예측)

  • Shin, Dong-Kun;Chung, Kyung-Yong
    • The Journal of the Korea Contents Association
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    • v.11 no.6
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    • pp.1-7
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    • 2011
  • The methodology of KOSPI forecast has been considered as one of the most difficult problem to develop accurately since short-term KOSPI is correlated with various factors including politics and economics. In this paper, we presents a methodology for forecasting short-term trends of stock price for five days using the feature selection method based on a neural network with weighted fuzzy membership functions (NEWFM). The distributed non-overlap area measurement method selects the minimized number of input features by removing the worst input features one by one. A technical indicator are selected for preprocessing KOSPI data in the first step. In the second step, thirty-nine numbers of input features are produced by wavelet transforms. Twelve numbers of input features are selected as the minimized numbers of input features from thirty-nine numbers of input features using the non-overlap area distribution measurement method. The proposed method shows that sensitivity, specificity, and accuracy rates are 72.79%, 74.76%, and 73.84%, respectively.

Development of BPR Functions with Truck Traffic Impacts for Network Assignment (노선배정시 트럭 교통량을 고려한 BPR 함수 개발)

  • Yun, Seong-Soon;Yun, Dae-Sic
    • Journal of Korean Society of Transportation
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    • v.22 no.4 s.75
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    • pp.117-134
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    • 2004
  • Truck traffic accounts for a substantial fraction of the traffic stream in many regions and is often the source of localized traffic congestion, potential parking and safety problems. Truck trips tend to be ignored or treated superficially in travel demand models. It reduces the effectiveness and accuracy of travel demand forecasting and may result in misguided transportation policy and project decisions. This paper presents the development of speed-flow relationships with truck impacts based on CORSIM simulation results in order to enhance travel demand model by incorporating truck trips. The traditional BPR(Bureau of Public Road) function representing the speed-flow relationships for roadway facilities is modified to specifically include the impacts of truck traffics. A number of new speed-flow functions have been developed based on CORSIM simulation results for freeways and urban arterials.

High Resolution Probabilistic Quantitative Precipitation Forecasting in Korea

  • Oh, Jai-Ho;Kim, Ok-Yeon;Yi, Han-Se;Kim, Tae-Kuk
    • The Korean Journal of Quaternary Research
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    • v.19 no.2
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    • pp.74-79
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    • 2005
  • Recently, several attempts have been made to provide reasonable information on unusual severe weather phenomena such as tolerant heavy rains and very wild typhoons. Quantitative precipitation forecasts and probabilistic quantitative precipitation forecasts (QPFs and PQPFs, respectively) might be one of the most promising methodologies for early warning on the flesh floods because those diagnostic precipitation models require less computational resources than fine-mesh full-dynamics non-hydrostatic mesoscale model. The diagnostic rainfall model used in this study is the named QPM(Quantitative Precipitation Model), which calculates the rainfall by considering the effect of small-scale topography which is not treated in the mesoscale model. We examine the capability of probabilistic diagnostic rainfall model in terms of how well represented the observed several rainfall events and what is the most optimistic resolution of the mesoscale model in which diagnostic rainfall model is nested. Also, we examine the integration time to provide reasonable fine-mesh rainfall information. When we apply this QPM directly to 27 km mesh meso-scale model (called as M27-Q3), it takes about 15 min. while it takes about 87 min. to get the same resolution precipitation information with full dynamic downscaling method (called M27-9-3). The quality of precipitation forecast by M27-Q3 is quite comparable with the results of M27-9-3 with reasonable threshold value for precipitation. Based on a series of examination we may conclude that the proosed QPM has a capability to provide fine-mesh rainfall information in terms of time and accuracy compared to full dynamical fine-mesh meso-scale model.

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A Study on the Development of a High Resolution Snow Gauge (정밀 강설량계 개발을 위한 연구)

  • Lee, Bu-Yong
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.8 no.4
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    • pp.270-274
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    • 2006
  • This study proposes a new method for automatic recording of snowfall by a mass unit which is required in weather forecast and hydrology research. In this method the weight of a buoyancy bar submerged in a liquid is measured by a strain-gauge loadcell. Field test results of the strain-gauge loadcell showed good stability as well as high accuracy. Indoor tests of the instrument using a large tank of 120 cm diameter and 25 cm height connected to a small tank measured the liquid level with a good stability, showing a measurement error of less than 0.1 mm in a 100 mm range. This method of water depth measurement is very useful in measuring snowfall because it has no limitation on the funnel size of the instrument. In addition, an antifreezing solution instead of water used in the tank makes a heating system for melting snow unnecessary.