Intelligent Transportation Systems in Transitional and Developing Countries

Intelligent transportation systems (ITS) are state-of-the-art approaches based on information, communication and satellite technologies in mitigating traffic congestion, enhancing safety, and improving quality of environment. ITS are being used in many industrialized and emerging economies for the last two decades to facilitate traffic managers in tackling surface mobility problems. In the case of many developing countries, policy makers and practitioners have neglected this "non-conventional" approach on the pretext inter alia, "technological sophistication," cost and institutional ill-preparedness. This aims to underscore the importance and relevance of ITS for developing countries as a complementary tool in the 21^st century. In so doing, the intention is to bestow some fresh thinking into the transport debate that will serve as a catalyst for resolving mobility problems in developing countries still dwelling on conventional options.     

Buried small objects detected by UWB GPR

A ground penetrating radar (GPR) using short-pulse is developed to detect small and shallow metal objects buried underground. A bistatic mode in which the GPR system uses separate transmitting and receiving antennas is applied. A modified fat dipole antenna is developed for the transmitting and receiving antennas. The prototype of the system is tested in the real environment and 2D visualization of raw data is achieved. We show that the developed system has a good ability to detect underground metal objects, and even small targets of several centimeters.     

Measuring the economic benefits of an environmental monitoring satellite project: The value of information approach

This paper reports a first application of contingent valuation method to measure the value of information generated by earth science data from an environmental geostationary satellite payload called Geostationary Environmental Monitoring Satellite. The purpose of the space project is to improve the accuracy of air pollution information by enhancing air pollution monitoring and forecasting system coupled with conventional ground level monitoring stations located throughout South Korea.     

Response of the mid-latitude D-region ionosphere to the total solar eclipse of 22 July 2009 studied using VLF signals in South Korean peninsula

In this paper, we analyze VLF signals received at Busan to study the the D-region changes linked with the solar eclipse event of 22 July 2009 for very short (∼390 km) transmitter–receiver great circle path (TRGCP) during local noon time 00:36–03:13 UT (09:36–12:13 KST). The eclipse crossed south of Busan with a maximum obscuration of ∼84%. Observations clearly show a reduction of ∼6.2 dB in the VLF signal strength at the time of maximum solar obscuration (84% at 01:53 UT) as compared to those observed on the control days. Estimated values of change in Wait ionospheric parameters: reflection height (h′) in km and inverse scale height parameter (β) in km⁻¹ from Long Wave Propagation Capability (LWPC) model during the maximum eclipse phase as compared to unperturbed ionosphere are 7 km and 0.055 km⁻¹, respectively. Moreover, the D-region electron density estimated from model computation shows 95% depletion in electron density at the height of ∼71 km. The reflection height is found to increase by ∼7 km in the D-region during the eclipse as compared to those on the control days, implying a depletion in the Lyman-α flux by a factor of ∼7. The present observations are discussed in the light of current understanding on the solar eclipse induced D-region dynamics.     

The Lunar Reconnaissance Orbiter Diviner Lunar Radiometer Experiment

The Diviner Lunar Radiometer Experiment on NASA’s Lunar Reconnaissance Orbiter will be the first instrument to systematically map the global thermal state of the Moon and its diurnal and seasonal variability. Diviner will measure reflected solar and emitted infrared radiation in nine spectral channels with wavelengths ranging from 0.3 to 400 microns. The resulting measurements will enable characterization of the lunar thermal environment, mapping surface properties such as thermal inertia, rock abundance and silicate mineralogy, and determination of the locations and temperatures of volatile cold traps in the lunar polar regions.     

Investigating suitable orbits for the Swarm constellation mission – The frozen orbit

This paper proposes a suitable orbit design for the lower pair of ESA's Swarm constellation mission, flying side-by-side in near-polar and circular orbits with a separation of only 1.4° at ascending node. Both orbits are suggested to be frozen orbits to minimize the evolution, and an along-track separation strategy is applied to avoid collision risk. The characteristics of the proposed orbit type are examined through numerical techniques including high-fidelity perturbation models. The prime change from the initial configuration is an along-track separation. The perturbations causing the along-track drift are analyzed by switching on/off certain perturbations. The results indicate that the tesseral harmonics and the atmospheric drag yield dominant effects. The atmospheric drag effect shows a dependence on the local time of the ascending node. From two months of orbit propagation for the altitude 300 km the maximum along-track drift we obtain is about 80 km, which is still within the measurement requirement range. Several maneuver strategies for maintaining the proposed orbit design are suggested. The results analyzed for the proposed orbit design show that collision risk can be avoided by along-track separation within the frozen orbit design. Consequently, this combination is considered as a suitable approach for Swarm's lower pair.     

Effect of Fading on FM Reception with Cochannel Interference

The combined effect of cochannel interference and nonselective Rayleigh fading on the reception of analog FM signals in additive Gaussian noise is analyzed. Rice's click model for the breaking region is used. Analysis in the absence of interference is performed first and the effect of modulation on the click rate is found to be nearly negligible. For the case with cochannel interference the click rate is computed in the absence of modulation. Curves are given for detected signal-to-noise ratio (SNR) versus carrier-to-noise ratio (CNR) with signal-to-interference ratio (SIR) as a parameter and SNR versus SIR with CNR as a parameter. The results agree well with recently published results of a simulation study.     

Suboptimal filter design with pseudomeasurements for targettracking

A suboptimal Kalman filter design method is presented for the problem of tracking a maneuvering target. The design method is essentially based on linear target dynamics and linear-like structured measurements called pseudomeasurements. The pseudomeasurements are obtained by manipulating the original nonlinear measurements algebraically. The resulting filter has computational advantages over other filters with similar performance. Also, a variant of the Berg model is proposed as a target acceleration model under the assumption of a coordinated turn maneuver. The proposed model is consistent with the underlying assumption. Monte Carlo computer simulation results are included to demonstrate the effectiveness of the proposed suboptimal filter associated with the target acceleration model