• Title/Summary/Keyword: Generation Prediction

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A Study on the Database Generation of Propulsion Performance for Ships Optimum Routing System (선박 최적운항시스템을 위한 추진성능 데이터베이스 생성 연구)

  • Kim, Eun-Chan;Kang, Kuk-Jin;Lee, Han-Jin
    • Journal of Navigation and Port Research
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    • v.40 no.3
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    • pp.97-103
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    • 2016
  • The precise prediction of ships propulsion performance is very important to find out the ships optimum route. This paper describes the development of computer program to generate the database of propulsion performance for the ships optimum routing system. The propulsion performance of ship in the sea is caused by not only ships conditions such as drift and hull roughness, but also various sea conditions such as wave and wind. These prediction methods of added resistance are based on the ships speed trial analysis methods of the ISO 15016:2002 standard, and a few prediction methods of the wind and hull roughness are supplemented. These prediction methods have been applied to the comprehensive computer program. And the database calculation for the research ice breaker the Araon has been carried out, which shall be used for the calculation of optimum route. Furthermore, this program shall be used for the route optimization in global shipping routes.

Performance Prediction of Interleave-Division Multiple Access Scheme based on Log-likelihood Ratio (LLR) for An Efficient 4G Mobile Radio System (효율적4세대 이동무선시스템을 위한 대수가능성비 기반의 인터리버 분할 다중접속기술의 성능 예측)

  • Chung, Yeon-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.7
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    • pp.1328-1334
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    • 2009
  • This paper presents a prediction mechanism of performance for an efficient interleave-division multiple access (IDMA) scheme that is being considered as 4th generation mobile radio system. The scheme is based upon log-likelihood ratio (LLR) to predict the performance of the IDMA. The conventional IDMA system simply passes the LLR values to a coarse estimation process in the receiver over a pre-defined number of iterations for an acceptable performance. The proposed IDMA system uses the LLRs to predict its BER performance and thus the iterative operation at the receiver can significantly be reduced when the performance attains an acceptable level. Performance evaluation shows that the proposed scheme of the IDMA with the LLRs used for the prediction provides a comparable BER performance. The use of the LLRs can facilitate an efficient design of the IDMA system that is a strong candidate system for 4G mobile radio systems.

Design of a 1-D CRNN Model for Prediction of Fine Dust Risk Level (미세먼지 위험 단계 예측을 위한 1-D CRNN 모델 설계)

  • Lee, Ki-Hyeok;Hwang, Woo-Sung;Choi, Myung-Ryul
    • Journal of Digital Convergence
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    • v.19 no.2
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    • pp.215-220
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    • 2021
  • In order to reduce the harmful effects on the human body caused by the recent increase in the generation of fine dust in Korea, there is a need for technology to help predict the level of fine dust and take precautions. In this paper, we propose a 1D Convolutional-Recurrent Neural Network (1-D CRNN) model to predict the level of fine dust in Korea. The proposed model is a structure that combines the CNN and the RNN, and uses domestic and foreign fine dust, wind direction, and wind speed data for data prediction. The proposed model achieved an accuracy of about 76%(Partial up to 84%). The proposed model aims to data prediction model for time series data sets that need to consider various data in the future.

Accurate prediction of lane speeds by using neural network

  • Dong hyun Pyun;Changwoo Pyo
    • Journal of the Korea Society of Computer and Information
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    • v.28 no.5
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    • pp.9-15
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    • 2023
  • In this paper, we propose a method predicting the speed of each lane from the link speed using a neural network. We took three measures for configuring learning data to increase prediction accuracy. The first one is to expand the spatial range of the data source by including 14 links connected to the beginning and end points of the link. We also increased the time interval from 07:00 to 22:00 and included the data generation time in the feature data. Finally, we marked weekdays and holidays. Results of experiments showed that the speed error was reduced by 21.9% from 6.4 km/h to 5.0 km/h for straight lane, by 12.9% from 8.5 km/h to 7.4 km/h for right turns, and by 5.7% from 8.7 km/h to 8.2 km/h for left-turns. As a secondary result, we confirmed that the prediction accuracy of each lane was high for city roads when the traffic flow was congested. The feature of the proposed method is that it predicts traffic conditions for each lane improving the accuracy of prediction.

Assessment of AnnAGNPS Model in Prediction of a Rainfall-Runoff Relationship (AnnAGNPS 모형의 강우-유출해석력 평가)

  • Choi, Kyung-Sook
    • Journal of the Korean Association of Geographic Information Studies
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    • v.8 no.2
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    • pp.125-135
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    • 2005
  • Generation and transport of nonpoint source pollution, especially sediment-associated pollutants, are profoundly influenced by hydrologic features of runoff. In order to identify pollutant export rates, hence, clear knowledge of rainfall-runoff relationship is a pre-requisition. In this study, performance of AnnAGNPS model was assessed based on the ability of the model to predict rainfall-runoff relationship. Three catchments, each under different nearly single land use, were simulated. From the results, it was found that the model was likely to produce better predictions for larger catchments than smaller catchments. Because of using the daily time scale, the model could not account for short durations less than 24 hours, especially high intensity events with multiple peak flow that significantly contribute to the generation and transport of pollutants. Since CN information for regional areas has not been built up, a careful selection of CN is needed to achieve accurate prediction of runoff volume. Storm distribution also found to be considered as an important calibration parameter for the hydrologic simulation.

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Life Prediction Analysis of Power Generation Turbine Blades Through Creep Analysis (크리프 해석을 통한 터빈 블레이드의 수명 예측)

  • Park, Jung-Sun;Lee, Soo-Yong;Kim, Jong-Un;Lee, An-Sung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.8
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    • pp.103-111
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    • 2002
  • Steady-state creep analysis of power generation turbine blade is carried out considering thermal loads and centrifugal forces. Creep strains and stresses of the turbine blade are calculated for 3-D finite clement model of the turbine blade. From the numerical results, creep life of the turbine blade is predicted. The results of creep analysis during about 200 hours indicate that creep strains of the turbine blade do not reach the rupture strain of GTD111. Creep stresses of the turbine blade are relaxed as time increases. Maximum creep strain occurs at the tip section of the airfoil pressure surface. The maximum creep strain of the turbine blade is expected close to the rupture strain after 50,000 hours approximately. The turbine blade may not have creep damage for the starting procedure of the turbine.

Spatial and temporal distribution of Wind Resources over Korea (한반도 바람자원의 시공간적 분포)

  • Kim, Do-Woo;Byun, Hi-Ryong
    • Atmosphere
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    • v.18 no.3
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    • pp.171-182
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    • 2008
  • In this study, we analyzed the spatial and temporal distribution of wind resources over Korea based on hourly observational data recorded over a period of 5 years from 457 stations belonging to Korea Meteorological Administration (KMA). The surface and 850 hPa wind data obtained from the Korea Local Analysis and Prediction System (KLAPS) and the Regional Data Assimilation and Prediction System (RDAPS) over a period of 1 year are used as supplementary data sources. Wind speed is generally high over seashores, mountains, and islands. In 62 (13.5%) stations, mean wind speeds for 5 years are greater than $3ms^{-1}$. The effects of seasonal wind, land-sea breeze, and mountain-valley winds on wind resources over Korea are evaluated as follows: First, wind is weak during summer, particularly over the Sobaek Mountains. However, over the coastal region of the Gyeongnam-province, strong southwesterly winds are observed during summer owing to monsoon currents. Second, the wind speed decreases during night-time, particularly over the west coast, where the direction of the land breeze is opposite to that of the large-scale westerlies. Third, winds are not always strong over seashores and highly elevated areas. The wind speed is weaker over the seashore of the Gyeonggi-province than over the other seashores. High wind speed has been observed only at 5 stations out of the 22 high-altitude stations. Detailed information on the wind resources conditions at the 21 stations (15 inland stations and 6 island stations) with high wind speed in Korea, such as the mean wind speed, frequency of wind speed available (WSA) for electricity generation, shape and scale parameters of Weibull distribution, constancy of wind direction, and wind power density (WPD), have also been provided. Among total stations in Korea, the best possible wind resources for electricity generation are available at Gosan in Jeju Island (mean wind speed: $7.77ms^{-1}$, WSA: 92.6%, WPD: $683.9Wm^{-2}$) and at Mt. Gudeok in Busan (mean wind speed: $5.66ms^{-1}$, WSA: 91.0%, WPD: $215.7Wm^{-2}$).

Development of Prediction Model and Parameter Optimization for Second-Generation Magnetic Abrasive Polishing of Magnesium Alloy (마그네슘 합금강의 제2세대 자기연마에서 표면거칠기 예측모델 개발)

  • Kim, Sang-Oh;Lee, Sung-Ho;Kwak, Jae-Seob
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.4
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    • pp.401-407
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    • 2011
  • The conventional method of magnetic abrasive polishing is not suitable for non-magnetic materials because such polishing is basically possible when magnetic force exists and the magnetic force in non-magnetic materials is very low. The installation of an electromagnet under the working area of a non-magnetic material, which is called second-generation magnetic abrasive polishing in this study, can enhance the magnetic force. Experimental evaluation and optimization of process parameters for polishing magnesium alloy steel was performed by adopting the design of experiments and the response surface method. The results indicated that the intensity of the magnetic force and spindle speed are significant parameters that affect the improvement of surface roughness. A prediction model for the surface roughness of the magnesium alloy steel is developed using the second-order response surface method.

Prediction of Residual Layer Thickness of Large-area UV Imprinting Process (대면적 UV 임프린팅 공정에서 잔류층 두께 예측)

  • Kim, Kug Weon
    • Journal of the Semiconductor & Display Technology
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    • v.12 no.2
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    • pp.79-84
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    • 2013
  • Nanoimprint lithography (NIL) is the next generation photolithography process in which the photoresist is dispensed onto the substrate in its liquid form and then imprinted and cured into a desired pattern instead of using traditional optical system. There have been considerable attentions on NIL due to its potential abilities that enable cost-effective and high-throughput nanofabrication to the display device and semiconductor industry. Although one of the current major research trends of NIL is large-area patterning, the technical difficulties to keep the uniformity of the residual layer become severer as the imprinting area increases more and more. In this paper, with the rolling type imprinting process, a mold, placed upon the $2^{nd}$ generation TFT-LCD glass sized substrate($370{\times}470mm^2$), is rolled by a rubber roller to achieve a uniform residual layer. The prediction of residual layer thickness of the photoresist by rolling of the rubber roller is crucial to design the rolling type imprinting process, determine the rubber roller operation conditions-mpressing force & feeding speed, operate smoothly the following etching process, and so forth. First, using the elasticity theory of contact problem and the empirical equation of rubber hardness, the contact length between rubber roller and mold is calculated with consideration of the shape and hardness of rubber roller and the pressing force to rubber roller. Next, using the squeeze flow theory to photoresist flow, the residual layer thickness of the photoresist is calculated with information of the viscosity and initial layer thickness of photoresist, the shape of mold pattern, feeding speed of rubber roller, and the contact length between rubber roller and mold previously calculated. Last, the effects of rubber roller operation conditions, impressing force & feeding speed, on the residual layer thickness are analyzed with consideration of the shape and hardness of rubber roller.

Effects of Gas Generation due to Biodegradation on Long-term Landfill Settlement (매립장의 생분해로 인한 가스발생이 장기 침하에 미치는 영향)

  • Ahn, Tae-Bong;Chin, Han-Gyu;Han, Woon-Woo
    • Journal of the Korean GEO-environmental Society
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    • v.6 no.1
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    • pp.5-13
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    • 2005
  • The conventional settlement prediction method is not appropriate to model landfill settlement because it is very complex phenomenon. Biodegradation needs to be considered for long-term settlement since landfills are comprised of various organic materials and soils. As organic materials are decomposed, they directly influences on settlement producing LFG(Landfill Gas). Therefore, mathematical settlement prediction model is proposed based on the generated gas volume. As one of stabilization methods, leachate recycling system is adopted to model tests. Two model tests; one is leachate recycled, the other is non-recycled, are componented with proposed model and analysed regarding gas generation and settlement. The proposed mathematical model requires correction coefficients of 1.4 and 1.7 for non-recycled model and recycled, respectively. The recycled model showed 22% increase of long-term settlement more than the non-recycled model.

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