{"title":"The Analysis of Population in Taiwan Based on Grey Verhulst Method","authors":"Kun-Li Wen, Yi-Fung Huang","doi":"10.30016/JGS.200507.0003","DOIUrl":"https://doi.org/10.30016/JGS.200507.0003","url":null,"abstract":"The principle of population prediction is one of the most important policies for developing countries, and population numbers are a basis for the formula used by the government with very limited resources. If the population increases significantly, or growth is reversed, then the entire balance of the ecology will be seriously impacted. Therefore, at first, the article focuses on the use of the Grey Verhulst method trying to construct saturation numbers for the population. In this paper, a toolbox is also developed to provide a very convenient way of generating a great numerical analysis of a real case. Finally, an example is given to predict saturation numbers of the population numbers in Taiwan, and the results tell us it will not exceed 23 million. Based on the above methods, the full results not only provide the saturation numbers, but also can become the reference-making policy for the best layout of the population source.","PeriodicalId":50187,"journal":{"name":"Journal of Grey System","volume":"10 1","pages":"27-36"},"PeriodicalIF":1.6,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70054640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Forecasting the One-period-ahead Volatility of the International Stock Indices: GARCH Model vs. GM(1,1)-GARCH Model","authors":"Chin-Tsai Lin, Jui-Cheng Hung, Yi-Hsien Wang","doi":"10.30016/JGS.200507.0001","DOIUrl":"https://doi.org/10.30016/JGS.200507.0001","url":null,"abstract":"In this paper, we propose a hybrid model, denoted as GM(1,1)-GARCH, that combines the grey forecasting model with the GARCH model to enhance the one-step-ahead variance forecasting ability as compared to the traditional GARCH model. Due to the trite underlying volatility process is not observed, a range-based measure of ex post volatility is employed as a proxy for the unobservable volatility process in evaluating the forecasting ability. Four international stock indices are illustrated to carry out the empirical investigation, and out-of-sample periods are divided into all data, up-trending and down-trending ones. The results indicate that the one-step-ahead variance forecasts produced by GM(1,1)-GARCH(1,1) model have higher R^2 and lower MAE, RMSE and MAPE for most cases as compared to GARCH(1,1) model. As a whole, this results provides the evidences that the hybrid GM(1,1)-GARCH model could enhance one-period-ahead volatility forecasting ability of the traditional GARCH model.","PeriodicalId":50187,"journal":{"name":"Journal of Grey System","volume":"8 1","pages":"1-12"},"PeriodicalIF":1.6,"publicationDate":"2005-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70054556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Using GM(1, 1) Meshsmooth Model to Construct Secure Network Communication System","authors":"Yi-Fung Huang, Kun-Li Wen","doi":"10.30016/JGS.200412.0002","DOIUrl":"https://doi.org/10.30016/JGS.200412.0002","url":null,"abstract":"In this paper, we combined the public key cryptograph system proposed by Diffie and Hellman, with the infinite generation keys based on GM(1, 1) model , which in grey system theory, to establish the GM(1, 1) meshsmooth model to construct secure network communication system. The whole mathematics concept is used finite original code to create an infinite variables code sequence, and got the code from the known secrete key. In this paper, we define two parameters: cryptography sequence ψ and 3(superscript rd) order symmetric group S3 and presented six cryptography models to contribute our system. According to the implement of real case, the secrete value is high to O(The equation is abbreviated) for public system, and it is hard to calculate the code sequence by the present computing ability. Therefore, to break into this system by mathematical formula is no way nowadays. Besides, to promote the efficiency, we also develop a toolbox, it can not only to decrease the calculation time, but also examine the reliability of our system.","PeriodicalId":50187,"journal":{"name":"Journal of Grey System","volume":"24 1","pages":"75-82"},"PeriodicalIF":1.6,"publicationDate":"2004-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70054932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Using Hybrid Grey Model to Achieve Revenue Assurance of Telecommunication Companies","authors":"Yo-Ping Huang, Hsiu-Ping Yang","doi":"10.30016/JGS.200406.0006","DOIUrl":"https://doi.org/10.30016/JGS.200406.0006","url":null,"abstract":"This paper presents a hybrid intelligent system to achieve revenue assurance of telecommunication companies. The proposed system combines the grey prediction and artificial intelligence techniques to achieve a more accurate problem detector with a higher availability than those traditional audit approaches could provide. In the telecommunication companies, each revenue leakage may reach hundred millions of dollars annually. However, most practical problems in revenue assurance are very complicated and uncertain and can only be solved by human resources. A hybrid prediction model is thus introduced to tackle the problems. How to optimize the prediction model and how to measure the performance with precision and recall rates are also discussed. The paper finally exploits the empirical errors of revenue leakage as test samples to measure the prediction ability of our proposed methods and demonstrates the potential of revenue assurance for telecommunication companies.","PeriodicalId":50187,"journal":{"name":"Journal of Grey System","volume":"7 1","pages":"38-49"},"PeriodicalIF":1.6,"publicationDate":"2004-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70054667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Grey target concept in optimization techniques and its application to estimation of structural parameters in a weather model","authors":"Z. R. Shen, T. P. Mack","doi":"10.5555/90757.90764","DOIUrl":"https://doi.org/10.5555/90757.90764","url":null,"abstract":"","PeriodicalId":50187,"journal":{"name":"Journal of Grey System","volume":"1 1","pages":"79-89"},"PeriodicalIF":1.6,"publicationDate":"1989-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71143532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}