A HPC based cloud model for real-time energy optimisation

Recent research has emphasised that an increasing number of enterprises need computation environments for executing HPC (High Performance Computing) applications. Rather than paying the cost of ownership and possess physical, fixed capacity clusters, enterprises can reserve or rent resources for undertaking the required tasks. With the emergence of new computation paradigms such as cloud computing it has become possible to solve a wider range of problems due to their capability to handle and process massive amounts of data. On the other hand, given the pressing regulatory requirement to reduce the carbon footprint of our built environment, significant researching efforts have been recently directed towards simulation-based building energy optimisation with the overall objective of reducing energy consumption. Energy optimisation in buildings represents a class of problems that requires significant computation resources and generally is a time consuming process especially when undertaken with building simulation software, such as EnergyPlus. In this paper we present how a HPC based cloud model can be efficiently used for running and deploying EnergyPlus simulation-based optimisation in order to fulfil a number of objectives related to energy consumption. We describe and evaluate the establishment of such an application-based environment, and consider a cost perspective to determine the efficiency over several cases we explore. This study identifies the following contributions: (i) a comprehensive examination of issues relevant to the HPC community, including performance, cost, user perspectives and range of user activities, (ii) a comparison of two different execution environments such as HTCondor and CometCloud and determine their effectiveness in supporting simulation-based optimisation and (iii) a detailed performance analysis to locate the limiting factors of these execution environments.     

Managing Perplexity: Lessons from Inside the Romanian Business Culture

Despite the passage of several decades since the revolution of 1989, there is little professional literature designed to prepare foreign investors for the Romanian business culture. Visitors to this nation discover a friendly people who engage in business practices often characterized as perplexing, frustrating, and imbued with self-defeating actions. The communist period in Romania's history imbedded unethical behavior into the nation's culture, including the morally ambiguous practice of favor trading. This paper describes this central business activity and how it shapes business dealings and often undermines opportunities. The cultural context that created the favor trading environment is discussed, and methods for managing this perplexing practice are explained.     

Dynamic decision trees for building resilience into future eco-cities

Intensifying global urbanization and environmental changes bring about the imperative of sustainable urban development and decisions upon inescapable pressures and risks, but knowledge integration between disciplines is a limiting contextual challenge. This paper proposes a reformulation, in terms of urban risk management, of an earlier developed ontological scenario generation method. The procedure consists of several steps: (i) identification-and-prioritization of main pressures, (ii) paired discussion of pressures using four-cell matrices, (iii) re-visit of the pressures' priority order, (iv) articulation of short-listed pressures as decision-making questions, and (v) generation of scenarios via “yes/no” responses to each question, in their order of priority. In this article, the method feeds upon the general context described in recent multi-disciplinary urban studies and public strategic plans in the city of Iasi (Romania), to propose a formal procedure for enabling the acceleration of productive decision making towards city sustainability. Answering three top priority questions, namely “Implement a business-friendly and efficient governance system?”, “Develop a resource management system?”, and “Carry out a human capital accelerator strategy?” results in a 4-scenario set: Receding City, Wanting City, Promising City, Inspiring City. The scenarios are discussed in terms of systemic risks at the end of post-communist transition and beginning of the socio-economic convergence with Western Europe.     

Information Externalities,Neighborhood Characteristics and Home Mortgage Pricing and Underwriting

Theories of rational redlining suggest thinness in housing markets should lead to greater uncertainty in house price appraisals, increasing mortgage denial rates or pricing. Empirical tests found support for this theory in mortgage underwriting using 1990s data. Using 2006 data and bank‐specific regression models, we revisit this topic in light of two developments leading to the recent mortgage bubble: the widespread securitization that allowed banks to shift loan risk to investors and the advent of risk‐based pricing. Consistent with expectations, we find that information externalities have become economically very small and have shifted from underwriting to pricing decisions.     

Subprime Loan Default Resolutions: Do They Vary Across Mortgage Products and Borrower Demographic Groups?

This paper examines default outcomes for subprime first lien loans during the recent subprime mortgage boom. It conducts this investigation in two phases. The paper first examines factors associated with pre-foreclosure outcomes for subprime mortgages in default. It then examines factors associated with different outcomes for loans that enter foreclosure. These factors include less understood elements such as mortgage product features and borrower demographics. The analysis is based on detailed loan-level data and employs multinomial logit models in a hazard framework. Results show that default resolutions vary with product features and borrower demographics. Adjustable rate and interest-only mortgages, and loans with low- or no-documentation are more likely to enter foreclosure proceedings, and, once in foreclosure, are more likely to become REO. The existence of junior liens increases the probability of the loan remaining in default. Owner-occupancy is associated with lower likelihood of foreclosure initiation and REO, and greater likelihood of curing default. Additionally, default outcomes are impacted by local legal, economic and housing market conditions, and the equity in the home.     

The effect of the timing and spacing of births on the level of labor market involvement of married women

We analyze the effect of the timing and spacing of births on the labor supply of married women in a framework that accounts for the endogeneity of the labor market and fertility decisions, for the heterogeneity of the effects of children on labor supply and their correlation with the fertility decisions, and for the correlation of sequential labor market decisions. Delaying the first birth leads to higher pre-natal levels of labor market involvement and reduces the negative effect of the first child on labor supply. The effect of the second child increases with the spacing of the two births as women, returning to work after the first birth, finance child care time increasingly through reductions in market time. Individual heterogeneity is considerable; women with lower propensity for children have the first birth later in life and space subsequent births more closely together, work more before the birth of the first child, but face larger effects of children on their labor supply.     

Joint estimation of sequential labor force participation and fertility decisions using Markov chain Monte Carlo techniques

We analyze the effect of children on the labor supply of married women in a framework that accounts for the endogeneity of labor market and fertility decisions, for the heterogeneity of the effects of children and their correlation with the fertility decisions, and for the correlation of sequential labor market decisions. Women with stronger propensity for market work have fewer children, work more before the first birth, and face larger negative effects of children. The total effect of a child remains considerable long after birth; prior birth-related reductions in labor supply account for a significant share of the total effect.     

Determinants of the incidence of U.S. Mortgage Loan Modifications

This paper combines data on the performance of mortgage loans with detailed borrower, neighborhood, and property characteristics to examine the factors that determine the outcomes of seriously delinquent loans. We employ multinomial logit models in a hazard framework to explain how loan, borrower, property, servicer and neighborhood characteristics affect which of the following four outcomes results from a seriously delinquent loan: (1) the borrower cures the delinquency; (2) the borrower and lender agree to modify the loan; (3) the borrower suffers a liquidation (short sale, deed in lieu, foreclosure auction sale or REO); or (4) the loan remains delinquent. In particular, we focus on mortgage modification. We find that the outcomes of delinquent loans are significantly related to: current LTV, FICO scores, especially risky loan characteristics, the servicer of the loan, neighborhood housing price appreciation, and whether the borrower received foreclosure counseling.     

FHA vs. Subprime Mortgage Originations: Is FHA the Answer to Subprime Lending?

We analyze originations of mortgages guaranteed by the Federal Housing Administration (FHA) and of subprime mortgages—loans that dominate the non-prime mortgage market for riskier borrowers. Using home purchase and refinance loans data for 2005, we estimate that a sizeable number of borrowers who got subprime loans would have qualified for FHA loans, implying a potential net flow of borrowers from subprime to FHA, especially for refinance loans at a rate of about 30%. Also, consistent with the FHA’s modernization proposal to increase its loan limits, we find that increasing the limits on FHA loans could help to attract borrowers, mostly of home purchase loans, who are likely to be constrained by the lower-priced house limits. Our findings are generally in line with the recent increased flow of mortgages to FHA, and suggest that FHA loans could be the answer to the current subprime lending crisis.     

The paradigm of utilizing robots in the teaching process: a comparative study

This paper discusses a comparative study of the effects of using a humanoid robot for introducing students to personal robotics. Even if a humanoid robot is one of the more complicated types of robots, comprehension was not an issue. The study highlighted the importance of using real hardware for teaching such complex subjects as opposed to relatively cheap simulation environments. While the field of robotics is still in its infancy it benefits from a “wow” effect that can be utilized to positively influence the education of new specialists in this field. This comparative study, done at the Polytechnic University of Bucharest, highlights the educational benefits of this idea. Two groups of students took part on a completely volunteer basis in an “introduction to personal robotics” workshop. While one group only worked with simulators on computers, the other group was also given access to real robots in addition to the simulators. This allowed them to test their programs on a real platform and tweak them to compensate for differences between the virtual world and the real world. This second group had consistently and considerably better results than the first group.