cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Improving the Quality of Computational Science Software by Using Metamorphic Relations to Test Machine Learning Applications
Creators: name: Xie, Xiaoyuan
name: Ho, Joshua
name: Murphy, Christian
name: Kaiser, Gail E.
name: Xu, Baowen
name: Chen, Tsong Yueh
Publisher: name: Columbia University
Year: 2009
Subjects: Computer science
Machine learning
Computers--Scientific applications
Software engineering

description: Many applications in the field of scientific computing - such as computational biology, computational linguistics, and others - depend on Machine Learning algorithms to provide important core functionality to support solutions in the particular problem domains. However, it is difficult to test such applications because often there is no 'test oracle' to indicate what the correct output should be for arbitrary input. To help address the quality of scientific computing software, in this paper we present a technique for testing the implementations of machine learning classification algorithms on which such scientific computing software depends. Our technique is based on an approach called 'metamorphic testing', which has been shown to be effective in such cases. In addition to presenting our technique, we describe a case study we performed on a real-world machine learning application framework, and discuss how programmers implementing machine learning algorithms can avoid the common pitfalls discovered in our study. We also discuss how our findings can be of use to other areas of computational science and engineering.
Testing hydrostatic equilibrium in galaxy cluster MS 2137
Creators: name: Chiu, I-Non Tim
name: Molnar, Sandor M.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We test the assumption of strict hydrostatic equilibrium in galaxy cluster MS2137.3-2353 (MS 2137) using the latest CHANDRA X-ray observations and results from a combined strong and weak lensing analysis based on optical observations. We deproject the two-dimensional X-ray surface brightness and mass surface density maps assuming spherical and spheroidal dark matter distributions. We find a significant, 40%-50%, contribution from non-thermal pressure in the core assuming a spherical model. This non-thermal pressure support is similar to what was found by Molnar et al. (2010) using a sample of massive relaxed clusters drawn from high resolution cosmological simulations. We have studied hydrostatic equilibrium in MS 2137 under the assumption of elliptical cluster geometry adopting prolate models for the dark matter density distribution with different axis ratios. Our results suggest that the main effect of ellipticity (compared to spherical models) is to decrease the non-thermal pressure support required for equilibrium at all radii without changing the distribution qualitatively. We find that a prolate model with an axis ratio of 1.25 (axis in the line of sight over perpendicular to it) provides a physically acceptable model implying that MS 2137 is close to hydrostatic equilibrium at about 0.04-0.15 Rvir and have an about 25% contribution from non-thermal pressure at the center. Our results provide further evidence that there is a significant contribution from non-thermal pressure in the core region of even relaxed clusters, i.e., the assumption of hydrostatic equilibrium is not valid in this region, independently of the assumed shape of the cluster.
description: 11 pages, 4 figures, accepted for publication in ApJ
Two rings around one ball : stability and charge localization of [1 : 1] and [2 : 1] complex ions of [10]CPP and C60/70[*]
Creators: name: Freiberger, Markus
name: Minameyer, Martin B.
name: Solymosi, Iris
name: Frühwald, Stefan
name: Krug, Marcel
name: Xu, Youzhi
name: Hirsch, Andreas
name: Clark, Timothy
name: Guldi, Dirk
name: Delius, Max
name: Amsharov, Konstantin
name: Görling, Andreas
name: Pérez-Ojeda, M. Eugenia
name: Drewello, Thomas
Publisher: name: Universitäts- und Landesbibliothek Sachsen-Anhalt
Year: 2023
Subjects: subject: 540

description: We investigate the gas-phase chemistry of noncovalent complexes of [10]cycloparaphenylene ([10]CPP) with C60 and C70 by means of atmospheric pressure photoionization and electrospray ionization mass spectrometry. The literature-known [1 : 1] complexes, namely [10]CPP⊃C60 and [10]CPP⊃C70, are observed as radical cations and anions. Their stability and charge distribution are studied using energy-resolved collision-induced dissociation (ER-CID). These measurements reveal that complexes with a C70 core exhibit a greater stability and, on the other hand, that the radical cations are more stable than the respective radical anions. Regarding the charge distribution, in anionic complexes charges are exclusively located on C60 or C70, while the charges reside on [10]CPP in the case of cationic complexes. [2 : 1] complexes of the ([10]CPP2⊃C60/70)+⋅/−⋅ type are observed for the first time as isolated solitary gas-phase species. Here, C60-based [2 : 1] complexes are less stable than the respective C70 analogues. By virtue of the high stability of cationic [1 : 1] complexes, [2 : 1] complexes show a strongly reduced stability of the radical cations. DFT analyses of the minimum geometries as well as molecular dynamics calculations support the experimental data. Furthermore, our novel gas-phase [2 : 1] complexes are also found in 1,2-dichlorobenzene. Insights into the thermodynamic parameters of the binding process as well as the species distribution are derived from isothermal titration calorimetry (ITC) measurements.
Hadron Spectroscopy with COMPASS
Creators: name: Grube, Boris
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: COMPASS is a multi-purpose fixed-target experiment at the CERN Super Proton Synchrotron aimed at studying the structure and spectrum of hadrons. One primary goal is the search for new hadronic states, in particular spin-exotic mesons and glueballs. We present recent results of partial-wave analyses of (3π)^- and π^-η' final states based on a large data set of diffractive dissociation of a 190 GeV/c π^- beam on a proton target in the squared four-momentum-transfer range 0.1 < t' < 1 (GeV/c)^2. We also show first results from a partial-wave analysis of diffractive dissociation of K^- into K^-π^+π^- final states are presented.
description: 5 pages, 6 figures, proceedings of the "19th Particles and Nuclei International Conference" (PANIC11), MIT, Cambridge, MA, USA, July 24 - 29, 2011
Investigations into the morphological, agronomic, and nutritional diversity within breadfruit (Artocarpus, Moraceae) as a resource for food security
Creators: name: Jones, Andrew Maxwell Phineas
Publisher: name: University of British Columbia
Year: 2011

description: Global food security is one of the most pressing issues facing humanity in the 21st century, with the number of undernourished people reaching an unprecedented high of over 1 billion. The problem is most acute in rural areas in tropical climates. Breadfruit (Artocarpus, Moraceae), a high-yielding tropical staple food crop, has been identified under the International Treaty on Plant Genetic Resources for Food and Agriculture for its potential to impact food security. The Breadfruit Institute at the National Tropical Botanical Garden houses the largest breadfruit collection in the world which represents a vast diversity of botanical and nutritional characters developed through millennia of traditional breeding. Breadfruit exhibits a great degree of morphological variability with cultivars that produce small 500g seeded fruit to those that produce large 3.5 kg seedless fruit. Variation is also expressed in the 57 characteristics evaluated in this study, with deep implications regarding the history of breadfruit domestication and the utilization of this crop to bolster food security. Evaluation of agronomic diversity has classified breadfruit into 10 seasonality groups, including non-seasonal, early, and late season cultivars. Informed cultivar selection based on these data will allow the fruiting season to be extended, and year round production will be possible. Further, 94 cultivars of breadfruit along with two related species, Artocarpus camansi and Artocarpus mariannensis, were evaluated for nutritional quality in fresh fruit and flour. Breadfruit is a good source of calcium, copper, iron, potassium, magnesium, has similar levels of protein as many other tropical staple crops, and many cultivars produce pro-vitamin A carotenoids. Individual cultivars have been identified that would provide 20%-25% of the recommended daily adult requirement for protein, approximately 23.5% calcium, 97.4% copper, 19.2% iron, 48.1% potassium, 115.8% magnesium, 33.6% manganese, 0.6% sodium, 53.5% phosphorous, and 21.0% zinc of the recommended daily intake of a female between 19-30 years old, and enough pro-vitamin A carotenoids to fulfill over 60% of the minimum daily vitamin A requirement of adults. Together these data show the immense diversity present within breadfruit germplasm and provide a foundation to utilize this variability to provide food security in the tropics.
BotSwindler: Tamper Resistant Injection of Believable Decoys in VM-Based Hosts for Crimeware Detection
Creators: name: Bowen, Brian M.
name: Prabhu, Pratap
name: Kemerlis, Vasileios
name: Sidiroglou, Stelios
name: Keromytis, Angelos D.
name: Stolfo, Salvatore
Publisher: name: Columbia University
Year: 2010
Subjects: Computer science

description: We introduce BotSwindler, a bait injection system designed to delude and detect crimeware by forcing it to reveal itself during the exploitation of monitored information. Our implementation of BotSwindler relies upon an out-of-host software agent to drive user-like interactions in a virtual machine, seeking to convince malware residing within the guest OS that it has captured legitimate credentials. To aid in the accuracy and realism of the simulations, we introduce a low overhead approach, called virtual machine verification, for verifying whether the guest OS is in one of a predefined set of states. We provide empirical evidence to show that BotSwindler can be used to induce malware into performing observable actions and demonstrate how this approach is superior to that used in other tools. We present results from a user study to illustrate the believability of the simulations and show that financial bait information can be used to effectively detect compromises through experimentation with real credential-collecting malware.
Structural performance of box based cross laminated timber system used in floor applications
Creators: name: Chen, Yue
Publisher: name: University of British Columbia
Year: 2011

description: The current outbreak of Mountain Pine Beetle (MPB) in the province of British Columbia (B.C.) is the most extensive disturbance event occurring in North American forests in recorded history. The concept of converting the beetle killed wood into engineered wood products by defect removal and reconstitution is employed to maximize value recovery from the material. Cross Laminated Timber (CLT), which is produced in modular form and can be utilized as part of a structural system for floor, wall or roof elements, is considered as an excellent application of the concept. CLT originates from Europe. Such products have been developed as a proprietary product by individual companies aimed at servicing specific markets. There is a need to investigate different ways of making CLT and to define its structural performance suitable for North America. The main focus of this study is to investigate the structural performance of box based CLT system used in floor applications. Comprehensive three dimensional finite element models, which can be used to analyze the mechanical and vibration behavior of the plate and box type structures, were developed. Four prototype box elements, each having five replicates, were designed and manufactured locally. Third point bending tests were conducted on the specimens in the Timber Engineering and Applied Mechanics (TEAM) Laboratory at the University of British Columbia. The numerical analysis agreed well with experimental data in terms of vertical deflection and bending stiffness. Vibration, which is critical to floor serviceability, was also studied. Three types of excitation were applied to measure the fundamental frequency of the twenty specimens. Finite element analysis provided good predictions of fundamental frequency values comparing to the experimental results. A local built demonstration building, L41home, was presented and analyzed as an example using the tools developed in this study for CLT applications. As a pioneer research of CLT materials in North America, this work has contributed to the understanding of the structural performance of floor systems using CLT panels for the commercial and residential applications.
Modeling User Search-Behavior for Masquerade Detection
Creators: name: Ben Salem, Malek
name: Hershkop, Shlomo
name: Stolfo, Salvatore
Publisher: name: Columbia University
Year: 2010
Subjects: Computer science

description: Masquerade attacks are a common security problem that is a consequence of identity theft. Prior work has focused on user command modeling to identify abnormal behavior indicative of impersonation. This paper extends prior work by modeling user search behavior to detect deviations indicating a masquerade attack. We hypothesize that each individual user knows their own file system well enough to search in a limited, targeted and unique fashion in order to find information germane to their current task. Masqueraders, on the other hand, will likely not know the file system and layout of another user's desktop, and would likely search more extensively and broadly in a manner that is different than the victim user being impersonated. We extend prior research by devising taxonomies of UNIX commands and Windows applications that are used to abstract sequences of user commands and actions. The experimental results show that modeling search behavior reliably detects all masqueraders with a very low false positive rate of 0.13%, far better than prior published results. The limited set of features used for search behavior modeling also results in large performance gains over the same modeling techniques that use larger sets of features.
Search for resonant WZ production in the WZ to l nu l' l' channel in sqrt(s) = 7 TeV pp collisions with the ATLAS detector
Creators: name: ATLAS Collaboration
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: A generic search is presented for a heavy particle decaying to WZ to l nu l'l' (l, l' = e, mu) final states. The data were recorded by the ATLAS detector in sqrt(s) = 7 TeV pp collisions at the Large Hadron Collider and correspond to an integrated luminosity of 1.02 fb-1. The transverse mass distribution of the selected WZ candidates is found to be consistent with the Standard Model expectation. Upper limits on the production cross section times branching ratio are derived using two benchmark models predicting a heavy particle decaying to a WZ pair.
description: 8 pages plus author list (21 pages total), 4 figures, 4 tables, revised author list, matches published PRD version
Direct scheme for measuring the geometric quantum discord
Creators: name: Jin, Jia-sen
name: Zhang, Feng-yang
name: Yu, Chang-shui
name: Song, He-shan
Publisher: name: arXiv
Year: 2011
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose a scheme to directly measure the exact value of geometric quantum discord of an arbitrary two-qubit state. We only need to perform the projective measurement in the all anti-symmetric subspace and our scheme is parametrically efficient in contrast to the widely adopted quantum state tomography scheme in the sense of less parameter estimations and projectors. Moreover, the present scheme can be easily realized with the current experimental techniques.
description: 9 pages,1 figure, submitted to J. Phys. A: Math. Theor
Spectrogram: A Mixture-of-Markov-Chains Model for Anomaly Detection in Web Traffic
Creators: name: Song, Yingbo
name: Keromytis, Angelos D.
name: Stolfo, Salvatore
Publisher: name: Columbia University
Year: 2008
Subjects: Computer science

description: We present Spectrogram, a mixture of Markov-chains sensor for anomaly detection (AD) against web-layer (port 80) code-injection attacks such as PHP file inclusion, SQL-injection, cross-site-scripting, as well as memory layer buffer overflows. Port 80 is the gateway to many application level services and a large array of attacks are channeled through this vector, servers cannot easily firewall this port. Signature-based sensors are effective in filtering known exploits but cannot detect 0-day vulnerabilities or deal with polymorphism and statistical AD approaches have mostly been limited to network layer, protocol-agnostic modeling, weakening their effectiveness. N -gram based modeling approaches have recently demonstrated success but the ill-posed nature of modeling large grams have thus far prevented exploration of higher order statistical models. In this paper, we provide a solution to this problem based on a factorization into Markov-chains and aim to model higher order structure as well as content for web requests. Spectrogram is implemented in a protocol-aware, passive, network-situated, but CGI-layered, AD architecture and we show in our evaluation that this model demonstrates significant detection results on an array of real world web-layer attacks, achieving at least 97% detection rates on all but one dataset and comparing favorably against other AD sensors.
Complexes de groupes de type multiplicatif et groupe de Brauer non ramifié des espaces homogènes
Creators: name: Borovoi, Mikhail
name: Demarche, Cyril
name: Harari, David
Publisher: name: arXiv
Year: 2012
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14M17

description: Let k be a field, G a smooth connected linear algebraic group and X a homogeneous space of G over k, such that the geometric stabilizers are extensions of a smooth group of multiplicative type by a smooth connected characterfree group. If k has characteristic zero and if X^c is a smooth compactification of X over k, we obtain a formula for the algebraic Brauer group of X^c. Several variants are obtained in positive characteristic p, including the finite field case and the global field case, where the formulae describe the prime-to-p part of the algebraic unramified Brauer group of X, without assuming the existence of a smooth compactification of X. Moreover, assuming that stabilizers are connected, then our formulae hold for the prime-to-p part of the whole unramified Brauer group.
description: 42 pages
Generative leadership: profile of effective 21st century secondary principals
Creators: name: Smith, Alfred J.
Publisher: name: University of Calgary
Year: 2009

description: Bibliography: p. 306-318
description: An instrumental qualitative approach was used in this inquiry into the concerns of 21st century secondary school principals who operate within the context of accelerating technological growth, globalization, multiculturalism, political change, education reform, and publicly problematized student underachievement. The research focused on the combination of intelligent roles that effective principals enact to respond to the relentlessly accelerating and intensifying changes and demands that characterize their environment. Research data were collected by means of structured open-ended interviews with six effective urban secondary school principals, in Ontario, Canada. The constant comparison method was used to analyze and compare participants' description of their leadership decision-making and interacting, and to generate archetypal concepts that interpret and explain their ongoing resolving behaviour. The resulting core concept characterizes effective 21st century secondary school leadership as a generative process. Generative leadership entails the enacting of conservative, integrative, adaptive, and transformative intelligent roles in response to the effects of complexity and change. As well, the findings suggest that the prevailing economic and political context, coupled with the technology-mediated transparency and immediacy of demands, generates a moral dilemma for secondary school principals, as it prescribes the ethics and methods of the private sector, which yield expedient, not wholly sustainable improvements. Sustainable improvements require the authenticating, mutually-actualizing and transcendental ethics of moral, servant or transforming leadership. As characterized by the principals in this study, generative leadership represents a philosophy, methodology, praxis, and profile of effective secondary school leadership during times of accelerated complexity and change.
Identification of Decoherence-Free Subspaces Without Quantum Process Tomography
Creators: name: Mahler, D. H.
name: Rozema, L.
name: Darabi, A.
name: Steinberg, A. M.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Characterizing a quantum process is the critical first step towards applying such a process in a quantum information protocol. Full process characterization is known to be extremely resource-intensive, motivating the search for more efficient ways to extract salient information about the process. An example is the identification of "decoherence-free subspaces", in which computation or communications may be carried out, immune to the principal sources of decoherence in the system. Here we propose and demonstrate a protocol which enables one to directly identify a DFS without carrying out a full reconstruction. Our protocol offers an up-to-quadratic speedup over standard process tomography. In this paper, we experimentally identify the DFS of a two-qubit process with 32 measurements rather than the usual 256, characterize the robustness and efficiency of the protocol, and discuss its extension to higher-dimensional systems.
description: 6 pages, 5 figures
Masquerade Detection Using a Taxonomy-Based Multinomial Modeling Approach in UNIX Systems
Creators: name: Salem, Malek Ben
name: Stolfo, Salvatore
Publisher: name: Columbia University
Year: 2008
Subjects: Computer science

description: This paper presents one-class Hellinger distance-based and one-class SVM modeling techniques that use a set of features to reveal user intent. The specific objective is to model user command profiles and detect deviations indicating a masquerade attack. The approach aims to model user intent, rather than only modeling sequences of user issued commands. We hypothesize that each individual user will search in a targeted and limited fashion in order to find information germane to their current task. Masqueraders, on the other hand, will likely not know the file system and layout of another user's desktop, and would likely search more extensively and broadly. Hence, modeling a user search behavior to detect deviations may more accurately detect masqueraders. To that end, we extend prior research that uses UNIX command sequences issued by users as the audit source by relying upon an abstraction of commands. We devised a taxonomy of UNIX commands that is used to abstract command sequences. The experimental results show that the approach does not lose information and performs comparably to or slightly better than the modeling approach based on simple UNIX command frequencies.
FairTorrent: Bringing Fairness to Peer-to-Peer Systems
Creators: name: Sherman, Alex
name: Nieh, Jason
name: Stein, Clifford S.
Publisher: name: Columbia University
Year: 2008
Subjects: Computer science

description: The lack of fair bandwidth allocation in Peer-to-Peer systems causes many performance problems, including users being disincentivized from contributing upload bandwidth, free riders taking as much from the system as possible while contributing as little as possible, and a lack of quality-of-service guarantees to support streaming applications. We present FairTorrent, a simple distributed scheduling algorithm for Peer-to-Peer systems that fosters fair bandwidth allocation among peers. For each peer, FairTorrent maintains a deficit counter which represents the number of bytes uploaded to a peer minus the number of bytes downloaded from it. It then uploads to the peer with the lowest deficit counter. FairTorrent automatically adjusts to variations in bandwidth among peers and is resilient to exploitation by free-riding peers. We have implemented FairTorrent inside a BitTorrent client without modifications to the BitTorrent protocol, and compared its performance on PlanetLab against other widely-used BitTorrent clients. Our results show that FairTorrent can provide up to two orders of magnitude better fairness and up to five times better download performance for high contributing peers. It thereby gives users an incentive to contribute more bandwidth, and improve overall system performance.
Automatic User Interaction Detection and Scheduling with RSIO
Creators: name: Zheng, Haoqiang
name: Nieh, Jason
Publisher: name: Columbia University
Year: 2008
Subjects: Computer science

description: Response time is one of the most important factors for the overall usability of a computer system. We present RSIO, a processor scheduling framework for improving the response time of latency-sensitive applications by monitoring accesses to I/O channels and inferring when user interactions occur. RSIO provides a general mechanism for all user interactions, including direct interactions via local HCI devices such as mouse and keyboard, indirect interactions through middleware, and remote interactions through networks. It automatically and dynamically identifies processes involved in a user interaction and boosts their priorities at the time the interaction occurs to improve system response time. RSIO detects processes that directly handle a user interaction as well as those indirectly involved in processing the interaction, automatically accounting for dependencies and boosting their priorities accordingly. RSIO works with existing schedulers, processes that may mix interactive and batch activities, and requires no application modifications to identify periods of latency-sensitive application activity. We have implemented RSIO in Linux and measured its effectiveness on microbenchmarks and real applications. Our results show that RSIO is easy to use and can provide substantial improvements in system performance for latency-sensitive applications.
The Hunt for Exomoons with Kepler (HEK): I. Description of a New Observational Project
Creators: name: Kipping, David M.
name: Bakos, Gáspár Á.
name: Buchhave, Lars A.
name: Nesvorny, David
name: Schmitt, Allan
Publisher: name: arXiv
Year: 2012
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Two decades ago, empirical evidence concerning the existence and frequency of planets around stars, other than our own, was absent. Since this time, the detection of extrasolar planets from Jupiter-sized to most recently Earth-sized worlds has blossomed and we are finally able to shed light on the plurality of Earth-like, habitable planets in the cosmos. Extrasolar moons may also be frequent habitable worlds but their detection or even systematic pursuit remains lacking in the current literature. Here, we present a description of the first systematic search for extrasolar moons as part of a new observational project called "The Hunt for Exomoons with Kepler" (HEK). The HEK project distills the entire list of known transiting planet candidates found by Kepler (2326 at the time of writing) down to the most promising candidates for hosting a moon. Selected targets are fitted using a multimodal nested sampling algorithm coupled with a planet-with-moon light curve modelling routine. By comparing the Bayesian evidence of a planet-only model to that of a planet-with-moon, the detection process is handled in a Bayesian framework. In the case of null detections, upper limits derived from posteriors marginalised over the entire prior volume will be provided to inform the frequency of large moons around viable planetary hosts, eta-moon. After discussing our methodologies for target selection, modelling, fitting and vetting, we provide two example analyses.
description: 21 pages, 8 figures, 4 tables, accepted in ApJ
Example application under PRET environment: Programming a MultiMediaCard
Creators: name: Dedhia, Devesh
Publisher: name: Columbia University
Year: 2009
Subjects: Computer science

description: PRET philosophy proposes the temporal characteristics to be made predictable. However for various applications the PRET processor will have to interact with a non predictable environment. In this paper an example of one such environment, an MultiMediaCard (MMC) is considered. This paper illustrates a method to make the response of the MMC predictable.
Using surface deformation to infer reservoir dilation induced by injection
Creators: name: Nanayakkara, Asanga Sanjeewee
Publisher: name: University of Calgary
Year: 2008

description: Bibliography: p. 232-331
description: This research project, using Truax's Scale for the Measurement of Accurate Empathy and an adapted version of Warman's Counseling Appropriateness Check-List, attempted to investigate the relationship between counselor empathy and student perception of counselor role. Results of the study indicated that counselors rated "high" in empathy were considered to be significantly more appropriate persons to consult for advice for personal-social problems than counselors rated "low". No significant differences were obtained for educational vocational problems. Female students in contrast to males considered the counselor to be significantly more appropriate for discussion of both problem areas. Grade 9 students considered the counselor to be significantly more appropriate for discussion of educational-vocational concerns than did grade 7 or grade 8 students. The results of this study and their implications were briefly discussed.
Reconstruction of a Nonminimal Coupling Theory with Scale-invariant Power Spectrum
Creators: name: Qiu, Taotao
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: A nonminimal coupling single scalar field theory, when transformed from Jordan frame to Einstein frame, can act like a minimal coupling one. Making use of this property, we investigate how a nonminimal coupling theory with scale-invariant power spectrum could be reconstructed from its minimal coupling counterpart, which can be applied in the early universe. Thanks to the coupling to gravity, the equation of state of our universe for a scale-invariant power spectrum can be relaxed, and the relation between the parameters in the action can be obtained. This approach also provides a means to address the Big-Bang puzzles and anisotropy problem in the nonminimal coupling model within Jordan frame. Due to the equivalence between the two frames, one may be able to find models that are free of the horizon, flatness, singularity as well as anisotropy problems.
description: 31 pages, 4 figures
Gas hydrate dissociation structures in clay slopes
Creators: name: Gidley, Iain Dennis Charles
Publisher: name: University of Calgary
Year: 2008

description: Bibliography: p. 176-187
description: Dissociation of gas hydrates releases large quantities of water and methane gas, which, depending on the host sediment can cause increased pore pressures, volumetric expansion, and/or fluid escape structures, all which have the effect of reducing the sediment stability. To further our understanding of the interaction between gas released during dissociation and the sediment that contains the hydrates, small scale physical models, using synthetic materials that enabled the dissociation process to be captured by high speed cameras, as well as a calibrated and verified finite element model were created. The results of the investigation show that slope angle affects the orientation of the fluid escape structures, depth of burial of the hydrate and a stiff overburden affect the amount of gas required for escape to occur and the violence of escape. Thin hydrate sheets cause the most cavity inflation and multiple hydrate nodules influence the orientation of the surface deformation.
Spreadable Connected Autonomic Networks (SCAN)
Creators: name: Reich, Joshua
name: Misra, Vishal
name: Rubenstein, Daniel Stuart
name: Zussman, Gil
Publisher: name: Columbia University
Year: 2008
Subjects: Computer science

description: A Spreadable Connected Autonomic Network (SCAN) is a mobile network that automatically maintains its own connectivity as nodes move. We envision SCANs to enable a diverse set of applications such as self-spreading mesh networks and robotic search and rescue systems. This paper describes our experiences developing a prototype robotic SCAN built from commercial, off-the-shelf hardware, to support such applications. A major contribution of our work is the development of a protocol, called SCAN1, which maintains network connectivity by enabling individual nodes to determine when they must constrain their mobility in order to avoid disconnecting the network. SCAN1 achieves its goal through an entirely distributed process in which individual nodes utilize only local (2-hop) knowledge of the network's topology to periodically make a simple decision: move, or freeze in place. Along with experimental results from our hardware testbed, we model SCAN1's performance, providing both supporting analysis and simulation for the efficacy of SCAN1 as a solution to enable SCANs. While our evaluation of SCAN1 in this paper is limited to systems whose capabilities match those of our testbed, SCAN1 can be utilized in conjunction with a wide-range of potential applications and environments, as either a primary or backup connectivity maintenance mechanism.
Memory Issues in PRET Machines
Creators: name: Shah, Nishant R.
Publisher: name: Columbia University
Year: 2008
Subjects: Computer science

description: In a processor design the premier issues with memory are (1) main memory allocation and (2) interprocess communication. These two mainly affect the performance of the memory system. The goal of this paper is to formulate a deterministic model for memory systems of PRET, taking into account all the intertwined parallelism of modern memory chips. Studying existing memory models is necessary to understand the implications of these factors to realize a perfectly time predictable memory system.
Decay rates for topological memories encoded with Majorana fermions
Creators: name: Goldstein, Garry
name: Chamon, Claudio
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Recently there have been numerous proposals to create Majorana zero modes in solid state heterojunctions, superconducting wires and optical lattices. Putatively the information stored in qubits constructed from these modes is protected from various forms of decoherence. Here we show that this is not the case. We present a generic method to study the effect of external perturbations on these modes. We focus on the case where there are no interactions between different Majorana modes either directly or through intermediary fermions. To quantify the rate of loss of the information stored in the Majorana modes we study the two-time correlators for qubits built from them. We analyze a generic gapped fermionic environment (bath) interacting via tunneling with different components of the qubit (different Majorana modes). We find that static (time-independent) perturbations are not harmful, and just lead to a depletion of the information stored that saturates in the long-time limit. On the other hand we find markedly different results for dynamic (time dependent) systems, with no coherence surviving in the long time limit. In particular we find that dephasing and energy fluctuations of the modes in the fermionic bath have adverse effects on the Majorana memories.
description: 27 pages, 5 figures, V2 some typos corrected and minor clarifications, V3: Some clarifications, accepted to PRB, V4 some corrections
The In Vivo Approach to Testing Software Applications
Creators: name: Murphy, Christian
name: Kaiser, Gail E.
name: Chu, Matt
Publisher: name: Columbia University
Year: 2008
Subjects: Computer science

description: Software products released into the field typically have some number of residual bugs that either were not detected or could not have been detected during testing. This may be the result of flaws in the test cases themselves, assumptions made during the creation of test cases, or the infeasibility of testing the sheer number of possible configurations for a complex system. Testing approaches such as perpetual testing or continuous testing seek to continue to test these applications even after deployment, in hopes of finding any remaining flaws. In this paper, we present our initial work towards a testing methodology we call in vivo testing, in which unit tests are continuously executed inside a running application in the deployment environment. These tests execute within the current state of the program (rather than by creating a clean slate) without affecting or altering that state. Our approach can reveal defects both in the applications of interest and in the unit tests themselves. It can also be used for detecting concurrency or robustness issues that may not have appeared in a testing lab. Here we describe the approach and the testing framework called Invite that we have developed for Java applications. We also enumerate the classes of bugs our approach can discover, and provide the results of a case study on a publicly-available application, as well as the results of experiments to measure the added overhead.
A PolyMUMPs Capacitive Micromachined Ultrasonic Transducer
Creators: name: Cai, Ming
Publisher: name: University of British Columbia
Year: 2011

description: This work presents the design of Capacitive Micromachined Ultrasonic Transducers (CMUTs) with one and multiple bottom electrodes and their fabrication using the PolyMUMPs technique provided by MEMSCAP Inc. It also reports a new behavioral model of the CMUTs written in VHDL-AMS, complemented by a comparison between finite element analysis, behavioral simulations and experimental measurements on the newly fabricated CMUT arrays. As an improvement on a previously developed VHDL-AMS CMUT behavioral model [1], where the CMUT was treated as a movable rigid plate capacitor, a mode decomposition approach was used in the present work to better approximate the dynamics of the CMUT membrane. Besides the frequency responses, time responses and electro-mechanical conversion efficiency, the simulation results also showed the electrostatic spring softening effect, and the optimization of the DC/AC voltage ratio that leads to a maximum transmitted acoustic power. The CMUT membrane capacitance variation predicted by the model compares favorably with results from the finite element analysis, with better matching than the previously developed models. Polytec Micro System Analyzer (Polytec MSA-500) using Laser Doppler Vibrometry was used for the experimental characterization, in which the pull-in voltage, vibration modes and their respective resonant frequencies were determined. Characterization results were compared with the ones from the finite element analysis and the behavioral model simulations, and excellent agreement was shown.
Retina: Helping Students and Instructors Based on Observed Programming Activities
Creators: name: Murphy, Christian
name: Kaiser, Gail E.
name: Loveland, Kristin
name: Hasan, Sahar
Publisher: name: Columbia University
Year: 2008
Subjects: Computer science

description: t is difficult for instructors of CS1 and CS2 courses to get accurate answers to such critical questions as 'how long are students spending on programming assignments?', or 'what sorts of errors are they making?' At the same time, students often have no idea of where they stand with respect to the rest of the class in terms of time spent on an assignment or the number or types of errors that they encounter. In this paper, we present a tool called Retina, which collects information about students' programming activities, and then provides useful and informative reports to both students and instructors based on the aggregation of that data. Retina can also make real-time recommendations to students, in order to help them quickly address some of the errors they make. In addition to describing Retina and its features, we also present some of our initial findings during two trials of the tool in a real classroom setting.
Low magnetic field reversal of electric polarization in a Y-type hexaferrite
Creators: name: Wang, Fen
name: Zou, Tao
name: Yan, Li-Qin
name: Liu, Yi
name: Sun, Young
Publisher: name: arXiv
Year: 2011
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Magnetoelectric multiferroics in which ferroelectricity and magnetism coexist have attracted extensive attention because they provide great opportunities for the mutual control of electric polarization by magnetic fields and magnetization by electric fields. From a practical point view, the main challenge in this field is to find proper multiferroic materials with a high operating temperature and great magnetoelectric sensitivity. Here we report on the magnetically tunable ferroelectricity and the giant magnetoelectric sensitivity up to 250 K in a Y-type hexaferrite, BaSrCoZnFe11AlO22. Not only the magnitude but also the sign of electric polarization can be effectively controlled by applying low magnetic fields (a few hundreds of Oe) that modifies the spiral magnetic structures. The magnetically induced ferroelectricity is stabilized even in zero magnetic field. Decayless reproducible flipping of electric polarization by oscillating low magnetic fields is shown. The maximum linear magnetoelectric coefficient reaches a high value of ~ 3.0\times10^3 ps/m at 200 K.
description: 9 pages, 5 figures, a couple of errors are corrected
Analysis of Clocks in X10 Programs (Extended)
Creators: name: Vasudevan, Nalini
name: Tardieu, Olivier
name: Dolby, Julian
name: Edwards, Stephen A.
Publisher: name: Columbia University
Year: 2008
Subjects: Computer science

description: Clocks are a mechanism for providing synchronization barriers in concurrent programming languages. They are usually implemented using primitive communication mechanisms and thus spare the programmer from reasoning about low-level implementation details such as remote procedure calls and error conditions. Clocks provide flexibility, but programs often use them in specific ways that do not require their full implementation. In this paper, we describe a tool that mitigates the overhead of general-purpose clocks by statically analyzing how programs use them and choosing optimized implementations when available. We tackle the clock implementation in the standard library of the X10 programming language---a parallel, distributed object-oriented language. We report our findings for a small set of analyses and benchmarks. Our tool only adds a few seconds to analysis time, making it practical to use as part of a compilation chain.
Troubled waters : the impact of North Sea oil in British politics, 1964-1979
Creators: name: Leaver, Daniel
Publisher: name: The University of St Andrews
Year: 2023
Subjects: subject: North Sea oil
subject: British politics and government, 1964-1979
subject: Conservative Party
subject: Labour Party
subject: Scottish nationalism
subject: Scottish National Party (SNP)
subject: HD9571.6L4
subject: Offshore oil industry--North Sea
subject: Petroleum in submerged lands--North Sea--Political aspects
subject: Great Britain--Politics and government--1964-1979
subject: Conservative Party (Great Britain)--History
subject: Labour Party (Great Britain)--History
subject: Scottish National Party--History
subject: Nationalism--Scotland

description: This thesis aims to explore the reactions of politicians to the discovery and development of North Sea oil in the United Kingdom between 1964 and 1979. In doing so, it attempts to consider why North Sea oil has largely been absent from existing narratives of post-war British history. It considers the politics of North Sea oil within the wider context of this period, looking at how it interacted with issues of economic modernisation, the relationship between the elected government and the trade unions, and the role of the state in the economy. Given the link between North Sea oil and the rise of the Scottish National Party in the early 1970s, it pays special attention to its association with constitutional change and the debate around Scottish devolution during this period. It presents an argument that North Sea oil proved too complex for both Labour and Conservative governments to fully incorporate into their agendas. For the 1964-70 and 1974-79 Labour governments, bringing oil into state ownership raised uncomfortable questions about potential retaliation by overseas governments regarding the operations of British firms such as BP. Likewise, for the 1970-74 Conservative government, and the government of Margaret Thatcher elected in 1979, keeping the British state out of the oil industry did not negate the fact that the government had to liaise with foreign governments who were heavily involved in their own oil industries. It also presents an argument that while the SNP’s rhetoric around North Sea oil was beneficial to the party during the early 1970s, there were a number of contradictions in the party’s oil policy that made it practically unfeasible. Ultimately, the party’s prioritisation of constitutional change over securing control of oil revenues after 1974 meant that the link between oil and constitutional change diminished during the later 1970s.
On dynamical adjoint functor
Creators: name: Mudrov, Andrey
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Algebra (math.QA)
subject: FOS: Mathematics

description: We give an explicit formula relating the dynamical adjoint functor and dynamical twist over nonalbelian base to the invariant pairing on parabolic Verma modules. As an illustration, we give explicit $U(sl(n))$- and $U_\hbar(sl(n))$-invariant star product on projective spaces.
Colorado water, October 2004
Creators: name: Blumanhourst, Gloria
name: Colorado Water Resources Research Institute, Publisher
Publisher: name: Mountain Scholar
Year: 2004
Subjects: subject: Water resources development -- Colorado
subject: Water use -- Colorado
subject: Water-supply -- Colorado
subject: Water-supply -- Management -- Colorado

description: The scope of the newsletter is devoted to enhancing communication between Colorado water users and managers and faculty at the research universities in the state.
description: Newsletter of the Water Center of Colorado State University.