Getting a Helping Hand: Parental Transfers and First-Time Homebuyers

A model that allows for inter vivos intergenerational transfers in a booming housing market is developed. The model is used to explain how transfers effect the first-time homebuyer’s consumption and housing decisions by alleviating borrowing constraints. The general implications of the model are tested using data from the leading Irish mortgage provider. We find that private transfers are targeted towards homebuyers that are liquidity constrained.Transfers, Housing, Borrowing Constraint

Getting a Helping Hand: Parental Transfers and First-Time Homebuyers

A model that allows for inter vivos intergenerational transfers in a booming housing market is developed. The model is used to explain how transfers effect the first-time homebuyer's consumption and housing decisions by alleviating borrowing constraints. The general implications of the model are tested using data from the leading Irish mortgage provider. We find that private transfers are targeted towards homebuyers that are liquidity constrained

A cost comparison of traditional drainage and SUDS in Scotland

The Dunfermline Eastern Expansion (DEX) is a 350 ha mixed development which commenced in 1996. Downstream water quality and flooding issues necessitated a holistic approach to drainage planning and the site has become a European showcase for the application of Sustainable Urban Drainage Systems (SUDS). However, there is minimal data available regarding the real costs of operating and maintaining SUDS to ensure they continue to perform as per their design function. This remains one of the primary barriers to the uptake and adoption of SUDS. This paper reports on what is understood to be the only study in the UK where actual costs of constructing and maintaining SUDS have been compared to an equivalent traditional drainage solution. To compare SUDS costs with traditional drainage, capital and maintenance costs of underground storage chambers of analogous storage volumes were estimated. A whole life costing methodology was then applied to data gathered. The main objective was to produce a reliable and robust cost comparison between SUDS and traditional drainage. The cost analysis is supportive of SUDS and indicates that well designed and maintained SUDS are more cost effective to construct, and cost less to maintain than traditional drainage solutions which are unable to meet the environmental requirements of current legislation

Modelling 802.11 Wireless Links

Analysis of the 802.11 CSMA/CA mechanism has received considerable attention recently. Bianchi [3] presents an analytic model under a saturated traffic assumption. Bianchi’s model is accurate, but typical network conditions are nonsaturated heterogenous. We present an extension of his model to a non-saturated environment. The model’s predictions, validated against simulation, accurately capture many interesting features of non-saturated operation. For example, the model predicts that peak throughput occurs prior to saturation. Our model also allows stations to have different traffic arrival rates, enabling us to address the question of fairness between competing flows

Modelling 802.11 Wireless Links

Analysis of the 802.11 CSMA/CA mechanism has received considerable attention recently. Bianchi [3] presents an analytic model under a saturated traffic assumption. Bianchi’s model is accurate, but typical network conditions are nonsaturated heterogenous. We present an extension of his model to a non-saturated environment. The model’s predictions, validated against simulation, accurately capture many interesting features of non-saturated operation. For example, the model predicts that peak throughput occurs prior to saturation. Our model also allows stations to have different traffic arrival rates, enabling us to address the question of fairness between competing flows

Decentralised Learning MACs for Collision-free Access in WLANs

By combining the features of CSMA and TDMA, fully decentralised WLAN MAC schemes have recently been proposed that converge to collision-free schedules. In this paper we describe a MAC with optimal long-run throughput that is almost decentralised. We then design two \changed{schemes} that are practically realisable, decentralised approximations of this optimal scheme and operate with different amounts of sensing information. We achieve this by (1) introducing learning algorithms that can substantially speed up convergence to collision free operation; (2) developing a decentralised schedule length adaptation scheme that provides long-run fair (uniform) access to the medium while maintaining collision-free access for arbitrary numbers of stations

Inbreeding alters intersexual fitness correlations in Drosophila simulans.

PublishedJournal ArticleIntralocus sexual conflict results from sexually antagonistic selection on traits shared by the sexes. This can displace males and females from their respective fitness optima, and negative intersexual correlations (r mf) for fitness are the unequivocal indicator of this evolutionary conflict. It has recently been suggested that intersexual fitness correlations can vary depending on the segregating genetic variation present in a population, and one way to alter genetic variation and test this idea is via inbreeding. Here, we test whether intersexual correlations for fitness vary with inbreeding in Drosophila simulans isolines reared under homogenous conditions. We measured male and female fitness at different times following the establishment of isofemale lines and found that the sign of the association between the two measures varied with time after initial inbreeding. Our results are consistent with suggestions that the type of genetic variation segregating within a population can determine the extent of intralocus sexual conflict and also support the idea that sexually antagonistic alleles segregate for longer in populations than alleles with sexually concordant effects.Foundation for Polish Science (FNP)NER

Investigating the validity of IEEE 802.11 MAC modeling hypotheses

As WLANs employing IEEE 802.11 have become pervasive, many analytic models for predicting their performance have been developed in recent years. Due to the complicated nature of the 802.11 MAC operation, approximations must be made to enable tractable mathematical models. In this article, through simulation we investigate the veracity of the approximations shared by many models that have been developed starting with the fundamental hypotheses in Bianchipsilas (1998 and 2000) seminal papers. We find that even for small numbers of station these assumptions that hold true for saturated stations (those that always have a packet to send) and for unsaturated stations with small buffers. However, despite their widespread adoption, we find that the commonly adopted assumptions that are used to incorporate station buffers are not appropriate. This raises questions about the predictive power of models based on these hypotheses