Symmetries of SU(2) Skyrmion in Hamiltonian and Lagrangian approaches

We apply the Batalin-Fradkin-Tyutin (BFT) method to the SU(2) Skyrmion to study the full symmetry structure of the model at the first class Hamiltonian level. On the other hand, we also analyze the symmetry structure of the action having the WZ term, which corresponds to this Hamiltonian, in the framework of the Lagrangian approach. Furthermore, following the BFV formalism we derive the BRST invariant gauge fixed Lagrangian from the above extended action.Comment: 14 pages, final revised version, to appear in Mod. Phys. Lett.

Two-dimensional heterogeneous photonic bandedge laser

We proposed and realized a two-dimensional (2D) photonic bandedge laser surrounded by the photonic bandgap. The heterogeneous photonic crystal structure consists of two triangular lattices of the same lattice constant with different air hole radii. The photonic crystal laser was realized by room-temperature optical pumping of air-bridge slabs of InGaAsP quantum wells emitting at 1.55 micrometer. The lasing mode was identified from its spectral positions and polarization directions. A low threshold incident pump power of 0.24mW was achieved. The measured characteristics of the photonic crystal lasers closely agree with the results of real space and Fourier space calculations based on the finite-difference time-domain method.Comment: 14 pages, 4 figure

Singapore’s Case of Institutional Arrangements for Fare Affordability

In public transport, achieving quality service and affordable fares with financial viability require concerted government intervention. Direct government intervention can jump-start the industry’s development but the case for intervening in the affairs of commercial companies is more debatable. Government has to decide on the roles of public agency that can act as the final arbiter between the interests of the commuters and the commercial operators. A useful framework to understand and debate where government intervention sits or should sit, is to map it against the triangular relationships of fare (or price), service standards (or quality) and viability (or cost). The price-cap model of fare regulation is feasible for public transport. For better public acceptance, a mechanism can be devised to allow for exceptional intervention by the fare regulation authority, to address any concerns regarding excessive profitability of commercial operators. Pegging the fare cap formula to macro-economic factors and sharing of productivity gains protect commuters, incentivise cost-efficiency and encourage non-farebox revenue maximisation. Periodic re-calibration of formula ensures currency and certainty. In a commercially driven industry structure and if market contestability is lacking, the regulatory agency needs a second policy lever to check on service quality and universal service obligations of commercial operators. Ticketing technology is a key enabler for any fare structure reform. Provision of ticket payment services should be open to multi-commercial card managers but the regulatory agency should retain the right to data use. A distance-based through-fare structure will eliminate the transfer penalty and support the hub-and-spoke model of public transport system. Fare structure reform can be done together with annual fare adjustments, but supporting infrastructure for integrated information services should be in place. A key challenge for the regulatory agency is to develop a revenue apportionment model that caters to both commercial and commuters’ interests. Fare affordability can be tracked using an indicator based on a characteristic household that is representative of the public transport users. Community-led financial help to the lowest quintile group is more targeted and it builds direct constituency relationships. Social fare introduction should be preceded by clear social objectives and such fares should be linked to the standard fare structure. This paper discusses how Singapore attempts to develop and effect a fare review mechanism, carry out fare structure reform and track fare affordability, from a practitioner’s perspective. The aim is to achieve quality service and affordable fares with financial viability.Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne

Singapore’s Case of Institutional Arrangements for Fare Affordability

In public transport, achieving quality service and affordable fares with financial viability require concerted government intervention. Direct government intervention can jump-start the industry’s development but the case for intervening in the affairs of commercial companies is more debatable. Government has to decide on the roles of public agency that can act as the final arbiter between the interests of the commuters and the commercial operators. A useful framework to understand and debate where government intervention sits or should sit, is to map it against the triangular relationships of fare (or price), service standards (or quality) and viability (or cost). The price-cap model of fare regulation is feasible for public transport. For better public acceptance, a mechanism can be devised to allow for exceptional intervention by the fare regulation authority, to address any concerns regarding excessive profitability of commercial operators. Pegging the fare cap formula to macro-economic factors and sharing of productivity gains protect commuters, incentivise cost-efficiency and encourage non-farebox revenue maximisation. Periodic re-calibration of formula ensures currency and certainty. In a commercially driven industry structure and if market contestability is lacking, the regulatory agency needs a second policy lever to check on service quality and universal service obligations of commercial operators. Ticketing technology is a key enabler for any fare structure reform. Provision of ticket payment services should be open to multi-commercial card managers but the regulatory agency should retain the right to data use. A distance-based through-fare structure will eliminate the transfer penalty and support the hub-and-spoke model of public transport system. Fare structure reform can be done together with annual fare adjustments, but supporting infrastructure for integrated information services should be in place. A key challenge for the regulatory agency is to develop a revenue apportionment model that caters to both commercial and commuters’ interests. Fare affordability can be tracked using an indicator based on a characteristic household that is representative of the public transport users. Community-led financial help to the lowest quintile group is more targeted and it builds direct constituency relationships. Social fare introduction should be preceded by clear social objectives and such fares should be linked to the standard fare structure. This paper discusses how Singapore attempts to develop and effect a fare review mechanism, carry out fare structure reform and track fare affordability, from a practitioner’s perspective. The aim is to achieve quality service and affordable fares with financial viability.Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne