Browsing by Author "Lin, Feng-Yu"

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CONFINED SPACE FUZZY PROPORTION MODEL FOR SHORT-TERM TRAFFIC FLOW PREDICTION
(2004)
Lan, Lawrence W.
;
Lin, Feng-Yu
;
Huang, Yi-San
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運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
This paper develops a confined space fuzzy proportion (CSFP) model to predict the short-term traffic flow dynamics. The rationale for prediction reasoning is based on the "fuzzy proportion" inference from similar historical trajectories that are within a "confined space" defined by a spatial threshold in the reconstructed state space. To perform the inference, we assign to each trajectory with unequal weight that is proportional to the relative distance to the latest (present) data vector. The United States I-35 Freeway one-minute flow data are used to construct and validate the proposed model. We employ Theil inequality coefficient (U) and its decomposed proportions to evaluate the prediction performance and to analyze the sources of prediction errors. The empirical results have demonstrated extremely high predictive capability of this CSFP model. The small bias and variance proportions of U statistic further indicate that the prediction model can successfully capture the trends and conspicuous fluctuations of one-minute traffic flow variations.
Software Vulnerability Patch Management with Semi-Markov Decision Process
(2013-11-01)
Huang, Chien-Cheng
;
Farn, Kwo-Jean
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Lin, Feng-Yu
;
Lin, Frank Yeong-Sung
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資訊管理與財務金融系註：原資管所+財金所
Information security incidents frequency has been increasing dramatically, the aim of this study is to analyze the state-space reachability problems through the transition of vulnerable status after the informative system vulnerability exposure. In this research we took into consideration the time factor to analyze the arrival time to reachable states problem discussed in stochastic Petri nets. The mean arrival time and variance of the process between starting from an initial state and arriving at reachable states. We will therefore elaborate a novel model based on the semi-Markov stochastic Petri nets model for analyzing the period between the exposure of the vulnerability and the completion of its patch. We use the semi-Markov process to analyze the state-space reachability problems of the stochastic Petri nets, resulting in a novel model for software vulnerability patch management. Moreover, we include also the concept of discounted multi-objective semi-Markov decision process to obtain the total of the efficient extreme point set.
SOME EVIDENCES OF CHAOTIC PHENOMENA IN SHORT-TERM TRAFFIC FLOW DYNAMICS: SURROGATE DATA APPROACH
(2004)
Lan, Lawrence W.
;
Lin, Feng-Yu
;
Huang, Yi-San
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
This paper employs wide-ranging indexes, including geometric plots and statistics, to examine whether chaotic phenomena exhibit in the short-term traffic flow dynamics. A field study is carried out using the one-minute flow time series data drawn from the United States 1-35 Freeway. The distinction of chaoticity and randomness is made between the original traffic data and their surrogates. We find that the geometric plots including iterated-function system clumpiness map, correlation function plot, and power spectrum have displayed apparent difference between the original and surrogate data and that the statistics including delay time, Hurst exponent, and relative complexity have also revealed noticeable discrepancy between them. These indexes have demonstrated strong evidences of chaotic, not random, phenomena in the nature of freeway one-minute traffic time series dynamics.