Bus headway in a rural area is usually much larger than that in an urban area. Providing real-time bus arrival information could make the public transit system more user-friendly and thus enhance its competitiveness among various transportation modes. As part of an operational test for rural traveler information systems currently ongoing in Blacksburg, Virginia, an experimental study has been conducted on forecasting the arrival time of the next bus with AVL techniques.

Based on the single scattering model of coda power spectrum analysis, digital waveform data of 50 events recorded by the real-time processing system of the Chengdu telemetry network are analyzed to estimate the Qc values of earth medium beneath the Chengdu telemetry network for several specified frequencies. It is found that the Qc shows the frequency dependency in the form of Qc = Q0f" in the range of 1.0 to 20.0Hz. Estimated Q0 ranges from 60.83 to 178.05, and n is found to be 0.713 to 1.159. The average value of Q0 and n are 117 and 0.978 respectively. This result indicates the strong frequency dependency of the attenuation of coda waves beneath the Chengdu telemetry network. Comparing with the results obtained in other regions of the world, it is found that Q0 -~ value and its change with frequency are similar to those in regions with strong tectonic activity. Key words: Chengdu telemetered network coda Q frequency dependency tectonic activityCoda wave, seismic energy after direct P and S waves, can be interpreted as backscattering waves from the numerous heterogeneity distributed randomly in the earth (Aid, 1969), and a single scattering model was proposed to interpret the origin of coda wave (Aid and Chouet, 1975). According to this model, the coda wave is a superposition of the waves scattered backward direction for once from the scatters distributed within the earth, and a method of determining the coda Q value from the time decay of coda waves was proposed. Now this method has widely applied to seismic records obtained in many areas of the world. Several important results on the frequency dependency of Qc value and its regional variation are obtained ( e.g. Rautian and Khalturin, 1978; Tsujiura, 1978; Aki, 1980; Sato,1986;Matsumoto and Hasegawa, 1989). These results show that the dependency of coda Q can be expressed approximately by the n-th power of frequency in the form of Qc = Q0f n. Matsumoto and Hasegawa(1989) estimated the regional variation of the Qc value beneath the northeastern part of Honshu, Japan. The result showed that the spatial distribution of Qc has a similar pattern to the S wave velocity structure, and Qc values in the regions near the active volcanoes show a strong frequency dependency. In the present study, based on the single scattering model, we estimate coda Q values at several frequency bands and their frequency dependency *

This research focus on the influence of the network convergence to the cable TV network enterprises. Based on the literature review, status quo and case study, this research combines the collection of open questionnaires, generalizes the influencing factors of the cable TV networks transformation that involve external and internal factors. The influence of external factors is evaluated by the influence of each factor to the component elements of the model, while that of the internal factors is estimated through that to the enterprises competitive advantage. Therefore, this research establishes the structural equation model, followed by the corresponding hypotheses and tests.

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