• Title/Summary/Keyword: grey system

Search Result 158, Processing Time 0.028 seconds

Expanding Information Services of Grey Literatures through the Central Management System (회색문헌 통합관리 체계에 관한 연구)

  • Kim, Mee-Jin;Nam, Young-Joon
    • Journal of Information Management
    • /
    • v.34 no.1
    • /
    • pp.1-18
    • /
    • 2003
  • The purposes of the study were to identify the characteristics and types of grey literatures, to investigate the factors restricting the sharing of grey literatures in Korea, and to make recommendations for the efficient collection and utilization system of grey literatures being produced and managed by either government agencies or government-supported research institutes in Korea. A survey instrument was designed to measure the current status of grey literature management systems and to elicit expert opinions from information professionals in information centers for an efficient system of grey literatures. It was found that information professionals considered the technical reports as the most important type of grey literatures, but maps and dissertations as the least important type of information value. Related to the participation for the central system of grey literatures, many respondents preferred to utilize the grey literatures owned by other information centers, but they showed a neutral interest level in sharing their information centers' grey literatures with other centers.

A Modified Grey-Based k-NN Approach for Treatment of Missing Value

  • Chun, Young-M.;Lee, Joon-W.;Chung, Sung-S.
    • Journal of the Korean Data and Information Science Society
    • /
    • v.17 no.2
    • /
    • pp.421-436
    • /
    • 2006
  • Huang proposed a grey-based nearest neighbor approach to predict accurately missing attribute value in 2004. Our study proposes which way to decide the number of nearest neighbors using not only the deng's grey relational grade but also the wen's grey relational grade. Besides, our study uses not an arithmetic(unweighted) mean but a weighted one. Also, GRG is used by a weighted value when we impute missing values. There are four different methods - DU, DW, WU, WW. The performance of WW(Wen's GRG & weighted mean) method is the best of any other methods. It had been proven by Huang that his method was much better than mean imputation method and multiple imputation method. The performance of our study is far superior to that of Huang.

  • PDF

Characterization of one Time-Sequential Stereoscopic 3D Display - Part I: Temporal Analysis -

  • Pierre, Boher;Thierry, Leroux;Collomb-Patton, Veronique
    • Journal of Information Display
    • /
    • v.11 no.2
    • /
    • pp.57-62
    • /
    • 2010
  • A method of characterizing time-sequential stereoscopic 3D displays based on the measurement of the temporal behavior of the systems vs. the grey levels is proposed. An Nvidia 3D vision kit with a 3D-ready SAMSUNG 2233RZ LCD display is characterized in the paper. OPTISCOPE SA especially designed for the precise measurements of the luminance and temporal behavior of LCD displays was used. The transmittance and response time of the shutter glasses was first evaluated. Then the grey-to-grey response times of the display were measured. The 2D and 3D behaviors of the display were then compared. Finally, the temporal behavior of the complete system was modeled, and the grey-level variations on one view were deduced as a function of the synchronization and level of the other eye. The main sources of imperfection were identified and quantified, and a full computation of the system performances was done.

Evaluation of Vehicle and Pedestrian Environments using Grey System Theory (Grey System Theory를 이용한 차량 및 보행환경 통합평가)

  • Lee, Jin-Gak;Son, Yeong-Tae;Han, Sang-Jin;Park, Jin-Yeong;Lee, Sang-Hwa
    • Journal of Korean Society of Transportation
    • /
    • v.28 no.4
    • /
    • pp.141-156
    • /
    • 2010
  • In this paper, understanding there is a limitation with a comprehensive and network approach for the evaluation of existing vehicle and pedestrian environments, the authors focus on developing an integrated approach to assessing these environments. The network evaluation here means the assessment at a three-dimensional level that includes evaluation methods of lines/axes in a spatial concept as well as integration of evaluation indicators being used for vehicles and the walking environment. Grey System Theory (GST) was applied based on the theoretical background for network and comprehensive integrated evaluation, and the evaluation of the vehicle and pedestrian environment was performed by assigning target areas to walking preference zones. As a result of the comprehensive evaluation and analysis by GST, even if the service level is the same as the operating indicators (Highway Capacity Manual) of the vehicle and pedestrian environment, or relatively better, it was identified that the total score could be varied over Grey Category because the observed data are calculated after considering the weights between evaluation indicators by the range of Grey Category on the comprehensive evaluation. Considering comprehensively these points, although the indicators on the operation of roads are relatively good, in the event that the indicators on the safety of roads are bad, it was known that the scores over Grey Category also could be changed. The result is that this evaluation method can be used to evaluate the network concept per lane (per axis) as well as to diagnose the current state by type of urban street in the future.

A Study on the Utilization of the Grey Literature in Digital Age (디지털 시대의 회색문헌 이용 활성화에 관한 연구)

  • Nam, Young-Joon
    • Journal of the Korean Society for information Management
    • /
    • v.19 no.4
    • /
    • pp.234-255
    • /
    • 2002
  • Despite of the importances, grey literatures are often overlooked as a resource in libraries because they have always had the reputation of being obscure and difficult to locate. Thus, an information system and network for the management of grey literature is essential to the improvement of Korean R&D in science and technology. The Results of the research are as follow : - Declare the clear definitions and types of grey literatures - Suggest the utilizing methods of grey literatures - Identify the major functions or requirements of National Information Center on Grey Literature.

A Study on the Treatment of Missing Value using Grey Relational Grade and k-NN Approach

  • Chun, Young-Min;Chung, Sung-Suk
    • 한국데이터정보과학회:학술대회논문집
    • /
    • 2006.04a
    • /
    • pp.55-62
    • /
    • 2006
  • Huang proposed a grey-based nearest neighbor approach to predict accurately missing attribute value in 2004. Our study proposes which way to decide the number of nearest neighbors using not only the dong's grey relational grade but also the wen's grey relational grade. Besides, our study uses not an arithmetic(unweighted) mean but a weighted one. Also, GRG is used by a weighted value when we impute a missing values. There are four different methods - DU, DW, WU, WW. The performance of WW(wen's GRG & weighted mean) method is the best of my other methods. It had been proven by Huang that his method was much better than mean imputation method and multiple imputation method. The performance of our study is far superior to that of Huang.

  • PDF

Stock assessment and Diagnosis of Flatted grey mullet, Mugil cephalus, in the coastal water of Yeosu (여수 연안의 숭어 (Mugil cephalus) 자원평가 및 진단)

  • PARK, Hee Won;SEO, Yong Il;KIM, Hee Yong;ZHANG, Chang Ik
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.51 no.3
    • /
    • pp.448-453
    • /
    • 2015
  • This study was performed to estimate biomass and to provide management plan through population ecological characteristics, including survival rate, instantaneous coefficient of natural and fishing mortalities, and age at first capture of Flathead grey mullet, Mugil cephalus, in the coastal waters of Yeosu. Survival rate (S) of the flathead grey mullet was 3.671. The instantaneous coefficients of natural mortality (M) and fishing mortality (F) was estimated to be 0.325/year, 0.962/year for flathead grey mullet. Also fist capure age of flathead grey mullet was 3.61year. The current biomass of the flathead grey mullet in the study area was estimated to be 19.6 M/T and $F_{0.1}$ and $F_{40%}$ were estimated 0.340/year, 0.225/year. For the stock assessment result, flathead grey mullet was not overfished but overfishing.

Age and growth of the flathead grey mullet (Mugil cephalus) in the coastal water of Yeosu (여수 연안 숭어 (Mugil cephalus)의 연령과 성장 연구)

  • Zhang, Chang-Ik;Park, Hee-Won;Kwon, Hyeok-Chan
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.47 no.3
    • /
    • pp.203-213
    • /
    • 2011
  • The age and growth of flathead grey mullet, Mugil cephalus, were studied using samples collected from the coastal water of Yeosu from September 2009 to August 2010. Spawning season estimated from the gonadosometic index (GSI) was from November to January. A method for increasing the readability of the otolith was described and criteria for the interpretation of otolith was provided. The annual ring was formed in September once a year. Annual ring in otolith for flathead grey mullet is validated for fish aged 1-8 using the marginal increment analysis. Using the sectioned otolith, between reader precision was 84%. Also, Within-reader agreement for sectioned otolith age readings was higher (reader 1=84%, reader 2=87%). The relationship between fork length and total weight was TW=$0.022FL^{2.818}$. The estimated von Bertalanffy growth parameters for the flathead grey mullet were $L_{\infty}$=67.97cm K=0.164/year and $t_o$=-0.81year.

Real-time Upstream Inflow Forecasting for Flood Management of Estuary Dam (담수호 홍수관리를 위한 상류 유입량 실시간 예측)

  • Kang, Min-Goo;Park, Seung-Woo;Kang, Moon-Seong
    • Journal of Korea Water Resources Association
    • /
    • v.38 no.12 s.161
    • /
    • pp.1061-1072
    • /
    • 2005
  • A hydrological grey model is developed to forecast short-term river runoff from the Naju watershed located at upstream of the Youngsan estuary dam in Korea. The runoff of the Naju watershed is measured in real time at the Naju streamflow gauge station, which is a key station for forecasting the upstream inflow and operating the gates of the estuary dam in flood period. The model's governing equation is formulated on the basis of the grey system theory. The model parameters are reparameterized in combination with the grey system parameters and estimated with the annealing-simplex method In conjunction with an objective function, HMLE. To forecast accurately runoff, the fifth order differential equation was adopted as the governing equation of the model in consideration of the statistic values between the observed and forecast runoff. In calibration, RMSE values between the observed and simulated runoff of two and six Hours ahead using the model range from 3.1 to 290.5 $m^{3}/s,\;R^2$ values range from 0.909 to 0.999. In verification, RMSE values range from 26.4 to 147.4 $m^{3}/s,\;R^2$ values range from 0.940 to 0.998, compared to the observed data. In forecasting runoff in real time, the relative error values with lead-time and river stage range from -23.4 to $14.3\%$ and increase as the lead time increases. The results in this study demonstrate that the proposed model can reasonably and efficiently forecast runoff for one to six Hours ahead.

Displacement prediction in geotechnical engineering based on evolutionary neural network

  • Gao, Wei;He, T.Y.
    • Geomechanics and Engineering
    • /
    • v.13 no.5
    • /
    • pp.845-860
    • /
    • 2017
  • It is very important to study displacement prediction in geotechnical engineering. Nowadays, the grey system method, time series analysis method and artificial neural network method are three main methods. Based on the brief introduction, the three methods are analyzed comprehensively. Their merits and demerits, applied ranges are revealed. To solve the shortcomings of the artificial neural network method, a new prediction method based on new evolutionary neural network is proposed. Finally, through two real engineering applications, the analysis of three main methods and the new evolutionary neural network method all have been verified. The results show that, the grey system method is a kind of exponential approximation to displacement sequence, and time series analysis is linear autoregression approximation, while artificial neural network is nonlinear autoregression approximation. Thus, the grey system method can suitably analyze the sequence, which has the exponential law, the time series method can suitably analyze the random sequence and the neural network method almostly can be applied in any sequences. Moreover, the prediction results of new evolutionary neural network method is the best, and its approximation sequence and the generalization prediction sequence are all coincided with the real displacement sequence well. Thus, the new evolutionary neural network method is an acceptable method to predict the measurement displacements of geotechnical engineering.