cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Towards Distributed Sensor Networks: An Extended Abstract
Creators: name: Yemini, Yechiam
name: Lazar, Aurel A.
Publisher: name: Columbia University
Year: 1982
Subjects: Computer science
Computer engineering

description: Consider a network consisting of a multitude of sensors distributed over some region. When a target crosses the region, observations will be taken by many sensors. These observations at the network nodes are noisy, partial, and have a varying degree of credibility. Therefore although each individual sensor may not have enough information the total system may possess enough information to track the targets. However the total information is distributed in the whole system and cannot be collected or processed by any single node in realtime due to limited communication and processing resources. Nor should it be centrally processed due to reliability and vulnerability considerations. The Distributed Sensor Networks (DSN) problem consists of building a sensor-communication-processing architecture to fuse noisy and partial observations from a multitude of geographically distributed sensors of varying credibilities. The program involves challenging problems of pushing the boundaries of signal processing technology, artificial intelligence and computer communication technology and integrating these disciplines. The objective of this paper is to present some of the interesting open problem areas arising in DSN.
A microscopic approach to nonlinear Reaction-Diffusion: the case of morphogen gradient formation
Creators: name: Boon, Jean Pierre
name: Lutsko, James F.
name: Lutsko, Christopher
Publisher: name: arXiv
Year: 2011
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We develop a microscopic theory for reaction-difusion (R-D) processes based on a generalization of Einstein's master equation with a reactive term and we show how the mean field formulation leads to a generalized R-D equation with non-classical solutions. For the $n$-th order annihilation reaction $A+A+A+...+A\rightarrow 0$, we obtain a nonlinear reaction-diffusion equation for which we discuss scaling and non-scaling formulations. We find steady states with either solutions exhibiting long range power law behavior (for $n>α$) showing the relative dominance of sub-diffusion over reaction effects in constrained systems, or conversely solutions (for $n
description: Article, 10 pages, 5 figures
Robustly collusion-proof implementation
Creators: name: Che, Yeon-Koo
name: Kim, Jinwoo
Publisher: name: Columbia University
Year: 2005
Subjects: Economics

description: A contract with multiple agents may be susceptible to collusion. We show that agents' collusion imposes no cost in a large class of circumstances with risk neutral agents, including both uncorrelated and correlated types. In those circumstances, any payoff the principal can attain in the absence of collusion, including the second best level, can be attained in the presence of collusion in a way robust to many aspects of collusion behavior. The collusion-proof implementation generalizes to a setting in which only a subset of agents may collude, provided that noncollusive agents' incentives can be protected via an ex post incentive compatible and ex post individually rational mechanism. Our collusion-proof implementation also sheds light on the extent to which hierarchical delegation of contracts can optimally respond to collusion.
Variational Monte Carlo Study of Anderson Localization in the Hubbard Model
Creators: name: Farhoodfar, A.
name: Gooding, R. J.
name: Atkinson, W. A.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: We have studied the effects of interactions on persistent currents in half-filled and quarter-filled Hubbard models with weak and intermediate strength disorder. Calculations are performed using a variational Gutzwiller ansatz that describes short range correlations near the Mott transition. We apply an Aharonov-Bohm magnetic flux, which generates a persistent current that can be related to the Thouless conductance. The magnitude of the current depends on both the strength of the screened disorder potential and the strength of electron-electron correlations, and the Anderson localization length can be extracted from the scaling of the current with system size. At half filling, the persistent current is reduced by strong correlations when the interaction strength is large. Surprisingly, we find that the disorder potential is strongly screened in the large interaction limit, so that the localization length grows with increasing interaction strength even as the magnitude of the current is suppressed. This supports earlier dynamical mean field theory predictions that the elastic scattering rate is suppressed near the Mott transition.
description: 7+epsilon pages
Implementing Descriptions Using Non-Von Neumann Parallelism
Creators: name: Lebowitz, Michael
Publisher: name: Columbia University
Year: 1983
Subjects: Computer science

description: Parallel processing has the potential for explaining and simplifying the algorithms used in many cognitive processes. One area particularly appropriate for an application of parallelism is memory search. Specifically, it is hard to even imagine one of the most appealing models of memory search that has been presented to date, the descriptions of Norman and Bobrow [Norman and Bobrow 79] being reasonably implemented in a sequential model. We show in this paper how descriptions can be implemented in a most straightforward fashion using a specific parallel architecture, that used by the NON-VON supercomputer [Shaw 82].
The Changing Role of the University TEFL Teacher in Improving the Students Communicative English Skill: From Passive Technician to Reflective Practitioner
Creators: name: Hirpassa, Motuma
Publisher: name: Journal of Science and Sustainable Development
Year: 2015

description: Prompted by increased concerns about the problems of education quality, this action research was conducted to study the role of the teachers in teaching English as a foreign language (TEFL) to improve the students Communicative English Skills at Ambo University. To achieve this objective, 198 (113 male and 85 female) first year (94) Pre-engineering and (104) Economics and Public Administration (FBE) undergraduate students of the University were purposively selected because the practitioner had been assigned to these particular students. The students were proportionally stratified into Experimental and Control groups based on the result of the pretest , field of study and sex. Both quantitative and qualitative data were obtained from the respondents through lesson observation, achievement test, questionnaire, focused group discussion, recorded classroom teaching observation and teaching material analyses. The obtained results were then triangulated. The study mainly focused on the role of the practitioner as a reflective teacher in selecting teaching materials and planning lessons, implementing it properly, conducting both reflection in- and reflection on- action activities, as the result of the reflections, planning and giving remedial actions to narrow the gaps between the students, and making the process cyclical. The overall result of the study showed that it is possible for the instructor to be a reflective practitioner in teaching the language to students of both natural and social sciences. The reflective teaching strategies adopted were found to have significantly improved the students results,’ leaning power and interest. In contrast to the control group, 70% of the students in the experimental group scored above 75% in the test. However, the low commitment of the students, the large class size and ill-designed teaching materials are some hindrances to implementing the reflective teaching strategies. Therefore, the solution to the problem lies in bringing about improvement on these hindrances
description: Journal of Science and Sustainable Development, Vol. 3 No. 1 (2015)
Optimal collusion-proof auctions
Creators: name: Che, Yeon-Koo
name: Kim, Jinwoo
Publisher: name: Columbia University
Year: 2006
Subjects: Economics

description: We study an optimal weak collusion-proof auction in an environment where a subset (or subsets) of bidders may collude not just on their bids but also on their participation. Despite their ability to collude on participation, informational asymmetry facing the potential colluders can be exploited significantly to weaken their collusive power. The second-best outcome - i.e., the noncollusive optimum - can be made weak collusion-proof, if at least one bidder is not collusive, or there are multiple bidding rings, or the second-best outcome involves a nontrivial probability of the object not being sold. In case the second-best is not weak collusion proof, we characterize an optimal weak collusion-proof auction. This auction involves nontrivial exclusion of collusive bidders - i.e., the object is not sold to any collusive bidder with positive probability.
Chern classes of free hypersurface arrangements
Creators: name: Aluffi, Paolo
Publisher: name: arXiv
Year: 2012
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14C17, 14J17, 32S25

description: The Chern class of the sheaf of logarithmic derivations along a simple normal crossing divisor equals the Chern-Schwartz-MacPherson class of the complement of the divisor. We extend this equality to more general divisors, which are locally analytically isomorphic to free hyperplane arrangements.
description: 16 pages
Optimal Solution of Nonlinear Equations Satisfying a Lipschitz Condition
Creators: name: Sikorski, Krzysztof A.
Publisher: name: Columbia University
Year: 1983
Subjects: Computer science

description: For a given nonnegative e we seek a point x* such that if(x*)[ l) satisfying a Lipschitz condition with the constant K and having a zero in B. The information operator on f consists of n values of arbitrary linear functionals which are computed adaptively. The point x* is constructed by means of an algorithm which is a mapping depending on the information operator. We find an optimal algorithm, i.e., algorithm with the smallest error, which uses n function evaluations computed adaptively. We also exhibit nearly optimal information operators, i.e., the linear functionals for which the error of an optimal algorithm that uses them is almost minimal. Nearly optimal information operators consists of n nonadaptive function evaluations at equispaced points xj in the cube B. This result exhibits the superiority of the T. Aird and J. Rice procedure ZSRCH (IMSL library [1]) over Sobol's approach [7] for solving nonlinear equations in our class of functions. We also prove that the simple search algorithm which yields a point x*=x k such that If(Xk)]= min If(xj)l is nearly optimal. The complexity, i.e., the minimal cost of solving our problem is roughly equal to (K/e)m.
Determining the cause of motor-vehicle related paediatric bicycling injuries
Creators: name: Pitt, Tona Michael Chase
Publisher: name: Cumming School of Medicine
Year: 2018
Subjects: subject: Injury Prevention
subject: Public Health
subject: Epidemiology
subject: Bicycling
subject: Paediatric
subject: Transportation
subject: built environment
subject: Quasi-Induced Exposure
subject: Epidemiology
subject: Public Health

description: Despite health benefits, bicycling as a form of active transportation has declined. Bicycle-motor vehicle collisions (BMVCs) pose a risk for severe injury to youth and are a leading deterrent to youth bicycling. This thesis aims to identify characteristics of BMVCs. Divided roads with no barrier, signage presence and peak traffic times had lower odds of severe injury in youth after BMVC. We adapted a culpability tool to Alberta police collision report data and used this tool to define a control group of drivers from collisions involving only motor vehicles. These controls were compared with drivers in BMVCs. Drivers older than 54 years had higher odds of youth BMVC, light trucks/vans had lower odds and driving between18:01hrs-24:00hrs had the highest odds of BMVC. It is possible to adapt culpability tools to other jurisdictions and can be used to address the often-neglected role of the driver in youth BMVCs.
Quantum Monte Carlo calculation of entanglement Renyi entropies for generic quantum systems
Creators: name: Humeniuk, Stephan
name: Roscilde, Tommaso
Publisher: name: arXiv
Year: 2012
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Lattice (hep-lat)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We present a general scheme for the calculation of the Renyi entropy of a subsystem in quantum many-body models that can be efficiently simulated via quantum Monte Carlo. When the simulation is performed at very low temperature, the above approach delivers the entanglement Renyi entropy of the subsystem, and it allows to explore the crossover to the thermal Renyi entropy as the temperature is increased. We implement this scheme explicitly within the Stochastic Series expansion as well as within path-integral Monte Carlo, and apply it to quantum spin and quantum rotor models. In the case of quantum spins, we show that relevant models in two dimensions with reduced symmetry (XX model or hardcore bosons, transverse-field Ising model at the quantum critical point) exhibit an area law for the scaling of the entanglement entropy.
description: 5+1 pages, 4+1 figures
Nurses survey responses about knowledge of nurse practice councils at St. Paul’s Hospital
Creators: name: Lee, Kelly
Publisher: name: University of British Columbia
Year: 2011

description: This electronic survey study was designed to examine the perceptions, knowledge and commitment of nursing staff regarding shared governance (Nurse Practice Council) at St. Paul’s Hospital (SPH). A cross-sectional survey design was used in this study. The study was conducted in the summer of 2010 at St. Paul’s Hospital, a tertiary hospital in Vancouver, B.C. A 114 nurses participated in the survey who were eligible and agreed to participate in the study. An electronic standardized SG survey was used to collect data for this study. The survey used Likert-like questions to measure the nurses’ perception, knowledge and commitment to the Nurse Practice Council (NPC). Additionally a small number of open-ended questions were used to verify the data from the Likert-like responses. Descriptive statistics were used to measure the level of perception, knowledge and commitment of nurses toward the Nurse Practice Council. Finally content analysis was employed to analyze the nurses’ responses to the open-ended questions. The SG study findings suggest: (1) Staff at SPH supports NPC and has a positive perception of NPC; (2) Staff members do not have enough knowledge about the NPC; and (3) Staff is not sure if administration at SPH is committed to the work of the NPC. The findings also indicate that staff believes the NPC has the potential to make a difference by increasing frontline nurse staff involvement, through education and awareness. Additionally leaders require education in order to increase administrative support and indirectly improve frontline attendance. Results of the one-way ANOVA showed that knowledge of NPC was statistically significant and varied according to practice area. However, no significant results were identified when examining perceptions and commitment according to practice area. In considering the literature that suggests perceptions, knowledge and commitment are essential in the implementation and sustainment of SG, it is surprising that the only significant result was knowledge. These findings indicated that more work is required to improve nurses’ perceptions of NPC, moreover improving the commitment level of staff to SG and the NPC.
Selfish Optimization in Computer Networks
Creators: name: Yemini, Yechiam
Publisher: name: Columbia University
Year: 1981
Subjects: Computer science
Mathematical optimization--Computer programs
Computer network protocols
Computer algorithms

description: This paper describes two applications of decentralized (Pareto) optimization to problems of computer communication networks. The first application is to develop a generalized principle for optimality of multi-hop broadcast channel access schemes. The second application is to decentralized flow-control in fixed virtual-circuit networks (e.g., SNA) using power maximization as the performance index. The decentralized approach to optimum network behavior yields, among other results, characterization of fair global objective functions, and optimal decentralized greedy network control algorithms. The main conclusion of this paper is that Pareto-optimality methods can be successfully used to develop optimal decentralized behavior algorithms where a centralized approach is (sometimes provably) not applicable.
Understanding and Improving Patient Flow in Outpatient Clinics and Emergency Departments
Creators: name: Zaerpour, Farzad
Publisher: name: Graduate Studies
Year: 2018
Subjects: subject: Patient Flow
subject: Operations Research
subject: Outpatient Clinics
subject: Emergency Departments
subject: Wait Times
subject: Health Care Management
subject: Engineering--Operations Research

description: Improving patient flow is a critical aspect of quality management in emergency departments and other healthcare settings. By improving the flow of patients in healthcare facilities, we can decrease wait times and boost patient and staff satisfaction. Many patients face physical pain and suffering while waiting for treatment in healthcare facilities. Long wait times may also result in treatable illnesses and injuries becoming chronic conditions. This dissertation includes three main chapters, corresponding to three essays on understanding and improving patient flow in outpatient clinics and emergency departments. In some outpatient clinics, lab tests must be completed before the clinic appointment, as doctors need to have the test results when seeing a patient. Achieving this tight coordination of a patient's testing and his or her subsequent doctor's appointment may be difficult in a facility where many physicians share the same testing resources. The second chapter presents a mixed-integer programming (MIP)-based approach to reduce the likelihood of a patient not completing testing in time for the clinic appointment. In the third chapter, we focus on improving patient flow in emergency departments by looking at the physician scheduling problem. We show that the scheduling of physicians has a direct impact on the waiting time of patients. Chapter 4 presents a new crowding measure in emergency departments that is based on patient volume and mix of patients. We assess the relevance and significance of the proposed measure.
title: The impact of realistic environmental chemical exposure on male gonadal development and reproductive health
Creators: name: Elcombe, Christopher S.
Publisher: name: University of Glasgow
Year: 2023

description: Continuing declines in human male reproductive health are of increasing concern. Many believe low-dose exposure to vast numbers of chemicals through the environment, particularly during fetal development, are a contributary factor in this decline. To address limitations with traditional, component-based methodologies of assessing chemical mixtures, this research utilised a unique, ovine based, whole-mixture exposure model. This model was used to investigate the impact of gestational exposure to realistic numbers of chemicals, at appropriately low doses, on male reproductive development. The research detailed herein characterises exposure-induced changes to the testes of neonatal, pre-pubertal, and adult male offspring of mothers exposed to an environmental chemical mixture prior to and during pregnancy. A testicular dysgenesis syndrome (TDS)-like phenotype was described in neonatal and prepubertal testes. This TDS-like phenotype was complemented by transcriptomic analyses which showed an extremely high degree of similarity between the testicular transcriptome of the affected pre-pubertal male offspring and those of human TDS patients. While this phenotype was not apparent in the same manner by adulthood, morphological and transcriptomic alterations were still apparent. This both exemplifies the potential for xenobiotic exposure during fetal development to impact reproductive health in later life, despite the cessation of exposure at birth, and indicates periods of post-partum vulnerability to xenobiotic exposure crucial to the persistence of or recovery from the TDS-like phenotype. Further investigations following transcriptomic analyses identified perturbations in the transcription, activation, and/or nuclear localisation of various transcription factors. Of these, there is supporting evidence that one (HIF1α) may have an important role in the pathogenesis of the TDS-like phenotype, while another (CREB1) may facilitate an amount of post-exposure recovery and might also be important in determining susceptibility or resistance to developing the TDS-phenotype. Overall, these findings strengthen the increasing evidence that gestational exposure to realistic levels and mixtures of environmental chemicals can have a negative impact on male reproductive health and provides leads for future investigations into the pathogenesis of TDS.
Molecular dynamics simulations investigate the pathway of substrate entry active site of rhomboid protease
Creators: name: Zhou, Hua
name: Yu, Hui
name: Zhao, Xi
name: Yang, Lianjuan
name: Huang, Xuri
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: Biochemistry
subject: Genetics
subject: FOS: Biological sciences
subject: Pharmacology
subject: Environmental Sciences not elsewhere classified
subject: Chemical Sciences not elsewhere classified
subject: Biological Sciences not elsewhere classified
subject: Information Systems not elsewhere classified
subject: Cancer
subject: Computational Biology

description: Rhomboid proteases can catalyze peptide bond cleavage and participate in abundant biological processes encompassing all branches of life; however, the pathway for substrate entry into its active site remains ambiguous. Here, the two possible pathways are preliminarily determined through molecular dynamics: One pathway is between Tm2 and Tm5, and the other is between Loop3 and Loop5. Then, the umbrella sampling simulations are performed to investigate the more feasible pathway for substrate entry. The results show that free energy barriers along the two pathways are similar; in the pathway 1, Trp236 and Trp157 as pivotal residues are responsible for the rotation of substrate in the binding process; in the pathway 2, among some important residues, the residue His150 plays an important role in substrate entry. Further, combining with previous experiment results, it is concluded that the substrate is inclined to enter into the active site along pathway 2. Our results are important for further understanding the function and catalysis mechanism of rhomboid proteases. Communicated by Ramaswamy H. Sarma
Assessing Temperature Tolerance in Ninespine Stickleback (Pungitius pungitius) in Response to Climate Change
Creators: name: Tufts, Teresa
Publisher: name: Graduate Studies
Year: 2018
Subjects: subject: thermal tolerance
subject: temperature
subject: Fish
subject: climate change
subject: Biology

description: Temperature is the most important environmental factor influencing fish abundance and distribution but, as temperatures rise globally, the consequences for fishes remains largely unknown. I used populations of ninespine stickleback (Pungitius pungitius) from the northern and southern parts of their range in a common environment to characterize thermal traits in association with varying temperatures. Cold tolerance differed between populations but heat tolerance did not. Furthermore, juveniles demonstrated less tolerance for temperature extremes. When incubated at elevated temperatures, populations exhibited higher plasticity in cold tolerance compared to heat tolerance. Plasticity in heat tolerance was associated with a number of trade-offs. The data suggest that cold tolerance is locally adapted and phenotypically plastic while heat tolerance is conserved and phenotypically restricted in this species. My thesis highlights the need for the inclusion of various life stages, time scales, and biotic interactions in climate change research to better predict its impacts on fishes.
Assessing Validity and Responsiveness of the Rotator Cuff Quality of Life Index
Creators: name: Campbell, Caitlin Dawn
Publisher: name: Graduate Studies
Year: 2018
Subjects: subject: shoulder
subject: psychometric assessment
subject: validity
subject: responsiveness
subject: quality of life
subject: rotator cuff
subject: outcome measurement
subject: Psychometrics

description: Background: The Rotator Cuff Quality of Life Index (RC-QOL) was developed to evaluate quality of life in patients with rotator cuff disease (RCD). This study provides additional validity and responsiveness testing over a 2-year period in accordance with the Consensus-Based Standards for the Selection of Health Measurement Instruments (COSMIN) guidelines. Methods: Sixty-six patients (mean age, 59±10) with RCD were evaluated. Methodology testing included criterion (concurrent) and content validity, and responsiveness. Results: Content validity was confirmed with a Cronbach α of 0.91 (95% CI; range, 0.92-0.95) and an absence of floor and ceiling effects. Criterion (concurrent) validity was confirmed using the Western Ontario Rotator Cuff Index as a reference standard (r=0.85, p<0.001). The effect size of distribution-based methods of determining responsiveness were large (0.99-1.09) compared to mixed- and anchor-based methods (0.47-0.8). All responsiveness calculations met minimum requirements for acceptable thresholds. Conclusion: The RC-QOL is a valid and responsive measure of health-related quality of life in patients with chronic RCD. The results of this study added to the methodologic quality assessment of the RC-QOL, completing 7 of 10 COSMIN criteria.
Dismal Arithmetic
Creators: name: Applegate, David
name: LeBrun, Marc
name: Sloane, N. J. A.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Number Theory (math.NT)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 06A06, 11A25, 11A63 (Primary) 11N37 (Secondary)

description: Dismal arithmetic is just like the arithmetic you learned in school, only simpler: there are no carries, when you add digits you just take the largest, and when you multiply digits you take the smallest. This paper studies basic number theory in this world, including analogues of the primes, number of divisors, sum of divisors, and the partition function.
description: 33 pages, 15 tables, 2 figures. Minor improvements Oct 25 2011
The Varying Openness of Digital Open Science Tools
Creators: name: Havemann, Jo
name: Bezuidenhout, Louise
Publisher: name: Zenodo
Year: 2020
Subjects: Digital Tools, Open Science,

description: Presentation held at the November 2020 OpenCider community event and in a breakout session at the JROST 2020 conference about the results of our manuscript doi: https://doi.org/10.12688/f1000research.26615.1.
Caps on political lobbying: Reply
Creators: name: Che, Yeon-Koo
name: Gale, Ian
Publisher: name: Columbia University
Year: 2006
Subjects: subject: Economics
subject: Political science
subject: FOS: Political science

description: Yeon-Koo Che and Ian Gale (1998) studied the impact of imposing a cap on lobbying expenditures. They showed that a cap may lead to (1) greater expected aggregate expenditures and (2) a less efficient allocation of a political prize. In their comment, Todd Kaplan and David Wettstein (2005) show that if the cap is not rigid (i.e., its effect on the cost of lobbying is continuous) it has no effect.
Teachers' Experiences of the Fort McMurray Wildfire: A Story of Surviving the Beast
Creators: name: Turcato, Whitney Cameron
Publisher: name: Graduate Studies
Year: 2018
Subjects: subject: emergency evacuation
subject: wildfire
subject: hermeneutics
subject: mental health nursing
subject: Education
subject: Mental Health
subject: Nursing
subject: FOS: Health sciences

description: There are groups of professionals who experience emergency evacuations differently from others due to their public service roles. These groups of professionals (teachers, nurses, social workers, physicians, healthcare aides and more) are responsible for the safety and wellbeing of others during an emergency evacuation. Due to an increased amount of responsibility and lack of control over when and with whom they evacuate, emergency evacuations affect these public service communities differently than others in the larger community. In this philosophical hermeneutic inquiry, four high school teachers were interviewed following the 2016 Fort McMurray wildfire evacuation in order to expand our understanding of the experience of these professionals during times of crisis. Findings exposed the duality of roles that these communities are faced with in times of crisis as well as the importance of story and story telling in the recovery of individual and community. This research offers new insights into the effects of disasters and emergency evacuations on these public service communities and allows mental health nurses and emergency management professionals to improve their understanding of appropriate interventions following disasters.
Smoothing consumption under income seasonality: Buffer stocks vs. credit markets
Creators: name: Chaudhuri, Shubham
name: Paxson, Christina
Publisher: name: Columbia University
Year: 2002
Subjects: Economics

description: Rural households in many developing economies have incomes that vary seasonally. We explore the implications of this income seasonality for household consumption. We use household-level data from three Indian villages to document seasonal patterns in income and consumption, and to test whether income seasonality produces seasonal consumption variation. Our basic finding is that while there does appear to be some seasonality in consumption patterns, it is much less pronounced than in the case of income, and more surprisingly, that the patterns are quite similar for households with very different seasonal income patterns. While this finding is consistent with well-functioning credit markets, we show, through simulations, that it is also consistent with a simple buffering model of consumption in which cautious households cannot borrow, but can save via the accumulation of assets. We provide evidence that suggests that households rely more on buffering behavior than on credit markets to smooth consumption under income seasonality.
Multi criteria evaluation of wood pellet utilization in district heating systems
Creators: name: Ghafghazi, Saeed
Publisher: name: University of British Columbia
Year: 2011

description: The hypothesis that this thesis investigates is that “the wood pellet is a competitive primary energy source option for generating district heat in Vancouver, BC”. The competitiveness of the wood pellet as an energy source is evaluated by investigating a major district heating project in Vancouver, BC in which the wood pellet option was compared with natural gas, sewer heat, and geothermal heat. It is observed that in addition to technical and economic factors, environmental and social acceptability criteria play an important role in the selection of the energy source for district heating systems. These include stakeholders’ concerns regarding global warming impacts associated with production and transportation of the wood pellets, as well as particulate matter emissions from wood pellet combustion at the facility. In order to investigate the hypothesis, detailed study of: (a) particle emissions formation and levels, (b) techno-economic performance, and (c) upstream and life-cycle environmental impacts when using wood pellets at the district heating centre, has been carried out. This thesis accepts the hypothesis in that: 1. Particulate emission levels from wood pellet combustion when an electrostatic precipitator flue gas cleaning system is used is below the 18 mg/m³ (20ºC, 101.3 kPa, 8% O₂) regulatory limits in Vancouver, BC, 2. The cost of heat generation (CAD/MWhth) from the wood pellet option (19.08~23.66) is comparable to that of the natural gas option (17.38) and well below those of the heat pump options (26.34~30.71), 3. Based on the upstream environmental impacts of the energy options, a single energy option, which outperforms others when all the impact categories at the same time are considered, cannot be identified. However, it was shown that the impact of upstream production and transportation activities for the wood pellet option does not offset the global warming mitigation advantage of this option. The greenhouse gas equivalent of upstream emissions from the wood pellet option is in the same order of magnitude as the renewable heat pump options, and has remarkably lower (less than 200 kgeq of GHG emissions per MWh of produced district heat) than that of the natural gas option.
Electronic Structure and Optical Absorption of Fluorographene
Creators: name: Liang, Yufeng
name: Yang, Li
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: A first-principles study on the quasiparticles energy and optical absorption spectrum of fluorographene is presented by employing the GW + Bethe-Salpeter Equation (BSE) method with many-electron effects included. The calculated band gap is increased from 3.0 eV to 7.3 eV by the GW approximation. Moreover, the optical absorption spectrum of fluorographene is dominated by enhanced excitonic effects. The prominent absorption peak is dictated by bright resonant excitons around 9.0 eV that exhibit a strong charge transfer character, shedding light on the exciton condensation and relevant optoelectronic applications. At the same time, the lowest-lying exciton at 3.8 eV with a binding energy of 3.5 eV is identified, which gives rise to explanation of the recent ultraviolet photoluminescence experiment.
description: 9 pages, 5 figures; MRS Proceedings (2011), 1370
Currency areas, volatility and intervention
Creators: name: Mundell, Robert A.
Publisher: name: Columbia University
Year: 2002
Subjects: Economics
Finance

description: On January 1, 1999, the euro was launched with eleven members and it instantly became the second most important currency in the world. It may prove to be the most important event in the history of the international monetary system since the dollar took over from sterling the role of dominant international currency. For the time being the mainstream of the world economy will be characterized by a tripolarism based on the dollar, euro and yen The new situation raises some old questions: Is the currency configuration of the world economy optimal? How many currencies does the world need? Which countries belong in a currency area? What is the optimum currency area? This paper will discuss the currency composition of the world economy today. It will discuss the prospects for expansion of the major currency areas and the problems arising from the volatility of exchange rates between them. It will argue that a restoration of a system of fixed exchange rates would have to begin with stabilization of the exchange rates between the dollar, euro and yen, and that a step in the right direction would be to evolve policies that provide for intervention in the foreign exchange market.
Effects of configurational disorder on adatom mobilities on TiAlN(001) surfaces
Creators: name: Alling, B.
name: Steneteg, P.
name: Tholander, C.
name: Tansnádi, F.
name: Petrov, I.
name: Greene, J. E.
name: Hultman, L.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We use metastable NaCl-structure Ti0.5Al0.5N alloys to probe effects of configurational disorder on adatom surface diffusion dynamics which control phase stability and nanostructural evolution during film growth. First-principles calculations were employed to obtain potential energy maps of Ti and Al adsorption on an ordered TiN(001) reference surface and a disordered Ti0.5Al0.5N(001) solid-solution surface. The energetics of adatom migration on these surfaces are determined and compared in order to isolate effects of configurational disorder. The results show that alloy surface disorder dramatically reduces Ti adatom mobilities. Al adatoms, in sharp contrast, experience only small disorder-induced differences in migration dynamics.
Focus Constraints on Language Generation
Creators: name: McKeown, Kathleen
Publisher: name: Columbia University
Year: 1983
Subjects: Computer science
Language and languages

description: Computer generation of natural language requires the ability to make reasoned choices from a large number of possible things to say as well as from a large number of expressive possibilties. This paper examines in detail how one influence on a generated text, focus of attention, can be used to constrain the many possibilities that a generation system must consider. A computational treatment of focus of attention is presented that can be used to constrain what the system needs to consider when deciding what to say next. In this process, information is produced that provides constraints on which words and syntactic structures best express the system's intent, thus ensuring that its resulting text is coherent. This analysis has been used in the fully implemented TEXT system which generates paragraph length responses to questions about database structure.
Spin and Orbital Angular Momenta of Electromagnetic Waves in Free Space
Creators: name: Mansuripur, Masud
Publisher: name: arXiv
Year: 2012
Subjects: subject: Optics (physics.optics)
subject: Mathematical Physics (math-ph)
subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: We derive exact expressions, in the form of Fourier integrals over the (k,w) domain, for the energy, momentum, and angular momentum of a light pulse propagating in free space. The angular momentum is seen to split naturally into two parts. The spin contribution of each plane-wave constituent of the pulse, representing the difference between its right- and left-circular polarization content, is aligned with the corresponding k-vector. In contrast, the orbital angular momentum associated with each plane-wave is orthogonal to its k-vector. In general, the orbital angular momentum content of the wavepacket is the sum of an intrinsic part, due, for example, to phase vorticity, and an extrinsic part, r_CM x p, produced by the linear motion of the center-of-mass r_CM of the light pulse in the direction of its linear momentum p.
description: 10 pages, 2 figures, 18 equations, 27 references
An integrated model for force prediction in peripheral milling operations
Creators: name: Zou, Guiping
Publisher: name: University of British Columbia
Year: 2011

description: This thesis is primarily concerned with the modeling of peripheral milling operations and, in particular, with cutting force prediction. The models developed incorporate novel approaches to deal with the difficulties described regarding edge geometry and chip thickness. The major contributions are outlined below. The first step in the analysis has been the development of models for small chip thickness. The model for cutting with a large cutting edge radius or chamfer (compared to chip thickness) is formulated as an Upper Bound where the primary and secondary zones are defined from a previous slip-line field model. This has the advantage of providing both force and moment equilibrium together with a realistic rake face stress situation. The second major contribution of the thesis lies in the formulation of a new model of oblique cutting and the direct application of this to the milling process. The new upper bound model that incorporates force equilibrium parallel to the cutting edge is proposed for oblique cutting operations. The energy approach is framed in terms of the normal shear angle and two fundamental variables that characterize the energy requirements of the oblique cutting process. Since the process of surface generation requires the analysis of entry and exit phenomenon, the attention has been directed towards simple slip-line field models of ploughing with single and double cutting edges. The analysis includes the influence of ploughing length on the ploughing/cutting transition. Finally the thesis presents the modeling of milling forces using the oblique cutting method as outlined and adding to the ploughing forces calculated from the new model. In addition, the model incorporates suitable material constitutive equations so that the influence of strain, strain rate, and temperature effects can be accounted for as chip thickness varies. The Upper Bound model at this stage is also able to incorporate the influence of surface slope and the kinematics of the process. The models developed have been tested with a variety of end mills on several work materials. These tests clearly demonstrate the need to account for the secondary factors not normally included in the modeling process.
Dendrocoris maculosus Thomas 1984
Creators: name: Thomas, D. B. Jr.
name: H. Brailovsky
Publisher: name: Zenodo
Year: 1999
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Pentatomidae
Dendrocoris
Dendrocoris maculosus

description: Dendrocoris maculosus Thomas 1984
Diagnosis. Vertex of head flat. Legs densely spotted black. Dorsal color grayish brown. Cicatrices concolorous with disk. Juga contiguous before tylus. Anterolateral pronotal margins subrectilinear in dorsal view. Abdominal tubercle present in female, absent in male. Abdominal spiracles ringed in black. Veins ofhemelytral membrane not reticulate. Posterior aspect of male pygophore with a pair of tiny black teeth attending medial emargination.
Distribution. MEXICO: Jalisco, N a y ari t, Guerrero.
Remarks. The darkly spotted legs are diagnostic.
description: Published as part of Thomas, D. B. Jr. & H. Brailovsky, 1999, Review of the genus Dendrocoris Bergroth with descriptions of new species (Pentatomidae: Heteroptera), pp. 1-9 in Insecta Mundi 13 on page 5
Spectral transformations in the regime of pulse self-trapping in a nonlinear photonic crystal
Creators: name: Novitsky, Denis
Publisher: name: arXiv
Year: 2011
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We consider interaction of a femtosecond light pulse with a one-dimensional photonic crystal with relaxing cubic nonlinearity in the regime of self-trapping. By use of numerical simulations, it is shown that, under certain conditions, the spectra of reflected and transmitted light possess the properties of narrow-band (quasi-monochromatic) or wide-band (continuum-like) radiation. It is remarkable that these spectral features appear due to a significant frequency shift and occur inside a photonic band gap of the structure under investigation.
description: 7 pages, 8 figures
Information channels in labor markets: On the resilience of referral hiring
Creators: name: Casella, Alessandra M.
name: Hanaki, Nobuyuki
Publisher: name: Columbia University
Year: 2005
Subjects: Labor economics

description: Economists and sociologists disagree over markets' potential to assume functions typically performed by networks of personal connections, first among them the transmission of information. This paper begins from a model of labor markets where social ties are stronger between similar individuals and firms employing productive workers prefer to rely on personal referrals than to hire on the anonymous market (Montgomery (1991)). However, we allow workers in the market to engage in a costly action that can signal their high productivity, and ask whether the possibility of signaling reduces the reliance on the network. We find that the network is remarkably resilient. To be effective signaling must fulfill two contradictory requirements: unless the signal is extremely precise, it must be expensive or it is not informative; but it must be cheap, or the network can undercut it.
False starts in history of searches for double beta decay, or Discoverless double beta decay
Creators: name: Tretyak, V. I.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: High Energy Physics - Experiment (hep-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: A collection of stories is presented on discoveries of double beta decay (including neutrinoless one) which were refuted in the subsequent investigations.
description: 6 pages, contribution to the Workshop on Calculation of Double Beta Decay Matrix Elements (MEDEX'11), Prague, June 13-16, 2011
Environmental Relations in Image Understanding: The Force of Gravity
Creators: name: Kender, John R.
Publisher: name: Columbia University
Year: 1983
Subjects: Computer science

description: This paper shows how assumptions and information concerning the external world properties of horizontal and vertical can aid in the analysis of images, even at the very lowest levels of processing. First, the author reviews the pervasiveness of the force of gravity, and its influence on most natural image understanding systems. Next, he derives several fundamental mathematical results relating phenomena in both the gradient space and the images space to the external world attributes of horizontal and vertical. He then shows how these results interrelate three imaging phenomena: the surfaces in the image, the external sensor parameters, and the environmental labels. It is detailed how, in general, specific information regarding any two of these phenomena can be used to quantitatively derive the third; occasionally one can do even better. Algorithms for such quantitative derivations are presented, including two based on the Hough transform. The author further shows how certain environmental perpendicularities can be exploited very efficiently, and even elegantly: ordinarily complex math simplifies to the extent that environmental distances can be directly read off the image. The power of such environmental labels is then demonstrated by an analysis of the source of ambiguity in a simple illusion-like image configuration. The paper concludes with an analysis of the class of heuristics that have been invoked throughout. They are seen to be instantiations of the shape-from-texture meta-heuristics that "near implies preferred" and "preferred implies simple."
Fractal Descriptors in the Fourier Domain Applied to Color Texture Analysis
Creators: name: Florindo, João Batista
name: Bruno, Odemir Martinez
Publisher: name: arXiv
Year: 2012
Subjects: subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Dynamical Systems (math.DS)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: The present work proposes the development of a novel method to provide descriptors for colored texture images. The method consists in two steps. In the first, we apply a linear transform in the color space of the image aiming at highlighting spatial structuring relations among the color of pixels. In a second moment, we apply a multiscale approach to the calculus of fractal dimension based on Fourier transform. From this multiscale operation, we extract the descriptors used to discriminate the texture represented in digital images. The accuracy of the method is verified in the classification of two color texture datasets, by comparing the performance of the proposed technique to other classical and state-of-the-art methods for color texture analysis. The results showed an advantage of almost 3% of the proposed technique over the second best approach.
description: Chaos, Volume 21, Issue 4, 2011