An Impact of Gas Prices on Transit Demand Using a Time-series Analysis and a Regression Analysis
Abstract Depending most of its energy sources on foreign countries, Korea efforts to reduce energy consumption in transportation. While studies on the relationship between gas price and transportation demand are many in number, most previous studies have focused on automobile and Seoul. This study analyzes the impact of gas price on transit (bus and subway) demand using monthly data and for various metropolitan areas (Seoul, Busan, Daejeon, Daegu and Gwangju). The research utilizes a time-series model and a multiple regression model, and calculates modal demand elasticities of gas price. The result shows that elasticities of subway demand with respect to gas price is higher than those of bus demand. In addition, elasticities of predominantly automobile cities are more likely to be more sensitive to gas price than those of cities with well-structured transit system.국내에서 소비되는 에너지의 대부분을 해외에 의존하고 있는 우리나라는 교통부문에서도 에너지 절감을 위해 많은 노력을 하고 있다 . 휘발유가격과 교통수요와의 관계는 국내외적으로 꾸준히 연구되어 왔으나 국내 선행연구는 승용차 및 수도권 중심으로 연구되어 왔다 . 본 연구에서는 휘발유가격이 대중교통수요에 미치는 영향을 분석하며 월별 자료를 활용하여 대중교통 수단별 (버스, 도시철도) 및 광역권별(수도권, 부산, 대전, 대구, 광주)로 실증적으로 비교분석했다. 분석을 위해 시계열모형과 다중회귀모형을 사용하였으며 회귀모형의 계수를 활용하여 유가에 대한 대중교통수요의 탄력성을 비교하였다 . 유가에 대한 수요탄력성이 버스보다 도시철도가 높게 나타났고 , 대중교통체계가 잘 갖춰진 수도권보다 승용차 의존적인 지방 광역권이 유가에 더 민감한 것으로 나타났다 .
Transit Ridership, Auto Gas Prices, and World Events
U.S. transit ridership research covers a wide field of traveler response factors but is surprisingly limited concerning the impact of auto gas prices. This situation is unfortunate, because gas prices have driven unprecedented growth in transit demand over the past 2 years. The research literature concerning cross-modal market effects of auto gas prices on transit demand is reviewed, including an outline of modeling work conducted in Australia. An analysis of U.S. national transit demand and auto gas trends is presented: the cross-elasticity of demand (e) is modeled in aggregate and separately for U.S. heavy rail, light rail, and commuter rail, and bus. Results indicate that, in aggregate, U.S. transit demand is at the low to medium end of sensitivity to auto gas prices for countries that have a low mode share. This finding is consistent with the lower cost of gas in the United States compared with other countries. The aggregate e has been measured as 0.12 and indicates that total U.S. transit demand will increase by 1.2% for every 10% increase in gas prices. U.S. light rail is particularly sensitive to gas prices, with e values of 0.27 to 0.38. Bus ridership is only slightly sensitive to gas prices (e = 0.04), and heavy rail is higher (0.17), consistent with most international evidence. A longitudinal model of trends has suggested some acceleration in transit mode sensitivity as world events have continuously affected prices; however, the model suggests that the effects since Hurricane Katrina (August 2005) have softened.
Spectroscopy of high rate events during active interrogation
Abstract Pulsed accelerators are being used for radiographic inspections in homeland security applications. Adding spectroscopic detection capability enables additional information to be extracted but challenges signal processing hardware. This work compares two approaches to cost-effective digital spectroscopy systems designed to handle these high rate scenarios. In the first system, the signal from a PMT is directly digitized and then deconvolved on a PC using standard techniques. Bypassing the preamplifier, this system can handle high count rates (>10 6  cps) from an LaCl 3 detector with no dead time and an energy resolution of 5% at 1.33 MeV. Spectra acquired from fission product gamma rays between interrogation pulses are shown. At higher rates, this approach is limited by the DAQ transfer rate to the PC. Instead, we tested a fast ADC (125 MSPS) and an FPGA that performed onboard, real-time digital signal processing (DSP). The energy spectrum is generated on the FPGA board during the measurement and transferred later. This system was tested in nuclear resonance fluorescence (NRF) experiments. Resonance peaks from NRF reactions are shown.