title: Bridge lane direction specifications for sustainable traffic management

authors: Foulds, James Richard

subjects: bridges

abstract: We present a deterministic model that specifies lane direction in a multi-laned bridge that has a movable barrier that divides the two directions of traffic flow, in order to reduce congestion. A probabilistic dynamic programming formulation for a stochastic extension of the model is also presented. Analysis of the special structure of the dynamic programming formulation provides new insights into important aspects of certain traffic planning problems and represents a useful addition to the traffic network planner's toolkit. A case study involving the lane direction management of an actual bridge is also provided.

text: Bridge lane direction specifications for sustainable traffic management We present a deterministic model that specifies lane direction in a multi-laned bridge that has a movable barrier that divides the two directions of traffic flow, in order to reduce congestion. A probabilistic dynamic programming formulation for a stochastic extension of the model is also presented. Analysis of the special structure of the dynamic programming formulation provides new insights into important aspects of certain traffic planning problems and represents a useful addition to the traffic network planner's toolkit. A case study involving the lane direction management of an actual bridge is also provided.

year: 2006

title: Development of a Supercapacitor based Surge Resistant Uninterruptible Power Supply

authors: Kozhiparambil, Parthasaradhy Kumaran

abstract: Uninterruptible Power Supplies (UPSs) provide short-term power back-up to sensitive electronic and electrical equipments, where an unexpected power loss could lead to undesirable outcomes. They usually bridge the connected equipment between the utility mains power and other long term back-up power systems like generators. A UPS also provides a “clean” source of power, meaning they filter the connected equipment from distortions in electrical parameters of the mains power like noise, harmonics, surges, sags and spikes. A surge resistant UPS or SRUPS is one that has the capability to withstand surges, which are momentary or sustained increases in the mains voltage, and react quickly enough to offer protection to the connected equipment from the same. Usually UPSs run off battery power when the utility mains power is absent. But the SRUPS developed in this design project uses super capacitors instead of battery packs. The reason for this is that the high energy-densities and medium power-densities offered by super capacitors allow for it to serve two purposes. One is to provide the DC power to operate the UPS in the absence of mains power, as an alternative to batteries. Secondly, super capacitors can withstand heavy momentary high current/voltage surges due to its high energy-density characteristics. Also as the life-time of super capacitors is much higher than that of conventional batteries and as they do not need regular topping-up or inspection, the end result is a truly maintenance-free UPS. Most commercial UPSs do not have inherent surge protection capabilities. The UPS is one entity while a discrete surge protection module is inserted between the utility mains and the UPS to provide for transient surge suppression. In the proposed SRUPS, the super capacitor, because of their inherent capability to absorb transient surges, forms a protective front end to the actual UPS rather than needing to have the involvement of discrete protection devices.

text: Development of a Supercapacitor based Surge Resistant Uninterruptible Power Supply Uninterruptible Power Supplies (UPSs) provide short-term power back-up to sensitive electronic and electrical equipments, where an unexpected power loss could lead to undesirable outcomes. They usually bridge the connected equipment between the utility mains power and other long term back-up power systems like generators. A UPS also provides a “clean” source of power, meaning they filter the connected equipment from distortions in electrical parameters of the mains power like noise, harmonics, surges, sags and spikes. A surge resistant UPS or SRUPS is one that has the capability to withstand surges, which are momentary or sustained increases in the mains voltage, and react quickly enough to offer protection to the connected equipment from the same. Usually UPSs run off battery power when the utility mains power is absent. But the SRUPS developed in this design project uses super capacitors instead of battery packs. The reason for this is that the high energy-densities and medium power-densities offered by super capacitors allow for it to serve two purposes. One is to provide the DC power to operate the UPS in the absence of mains power, as an alternative to batteries. Secondly, super capacitors can withstand heavy momentary high current/voltage surges due to its high energy-density characteristics. Also as the life-time of super capacitors is much higher than that of conventional batteries and as they do not need regular topping-up or inspection, the end result is a truly maintenance-free UPS. Most commercial UPSs do not have inherent surge protection capabilities. The UPS is one entity while a discrete surge protection module is inserted between the utility mains and the UPS to provide for transient surge suppression. In the proposed SRUPS, the super capacitor, because of their inherent capability to absorb transient surges, forms a protective front end to the actual UPS rather than needing to have the involvement of discrete protection devices.

year: 2011

title: Māori tourism geographies: Values, morals and diverse economies

authors: Ringham, Sandra Lee

subjects: Māori tourism

abstract: Māori working in tourism negotiate moral terrains of their own world and those of visiting tourists, all of which are layered with colonial and capitalist values of Aotearoa New Zealand and beyond. We draw on research with Māori tourism providers in the North Island’s central, coastal and northern regions to address the question: How and in what ways do Māori working in tourism (re)construct their places and identities through practising Māori values in Aotearoa New Zealand’s tourism spaces? It is argued, using empirical material from interviews and par­ticipant sensing—a more-than-seeing form of participant observation—that diverse Māori values and practices shape tourism terrains and vice versa. The participants, who work with or for Māori tourism providers, practise and integrate Māori values into their lived geographies, and in doing so challenge dominant understandings of tourism, many of which are based on colonial and capitalist values. In this way, the participants reclaim and perform self-determination within Aotearoa New Zealand’s tourism spaces. This article focuses on two key themes. First, we look back at how past experiences of colonisation shape contemporary tourism. Second, we discuss the diverse and powerful ways Māori values reshape tourism geographies with a view to the potentialities of Māori tourism’s diverse economies.

text: Māori tourism geographies: Values, morals and diverse economies Māori working in tourism negotiate moral terrains of their own world and those of visiting tourists, all of which are layered with colonial and capitalist values of Aotearoa New Zealand and beyond. We draw on research with Māori tourism providers in the North Island’s central, coastal and northern regions to address the question: How and in what ways do Māori working in tourism (re)construct their places and identities through practising Māori values in Aotearoa New Zealand’s tourism spaces? It is argued, using empirical material from interviews and par­ticipant sensing—a more-than-seeing form of participant observation—that diverse Māori values and practices shape tourism terrains and vice versa. The participants, who work with or for Māori tourism providers, practise and integrate Māori values into their lived geographies, and in doing so challenge dominant understandings of tourism, many of which are based on colonial and capitalist values. In this way, the participants reclaim and perform self-determination within Aotearoa New Zealand’s tourism spaces. This article focuses on two key themes. First, we look back at how past experiences of colonisation shape contemporary tourism. Second, we discuss the diverse and powerful ways Māori values reshape tourism geographies with a view to the potentialities of Māori tourism’s diverse economies.

year: 2016