bluuebunny/crossref_metadata_2025 huggingface dataset:
Enacting Scotland's ‘Written Constitution’: The Scotland Act 1998*
Authors: WINETROBE BARRY K.
Published: January 2011

The Scotland Act 1998 was one of the most significant pieces of constitutional legislation of the 1997–2010 Labour government. Yet, unlike the attempts to enact devolution in the 1970s, its parliamentary passage was relatively uncontroversial. In the 1970s, there was no party or public consensus for the proposed scheme, and no majority government to prevent various enforced amendments which ultimately led to its defeat in the March 1979 referendum. In the late 1990s, the situation was very different with much more consensus; a huge parliamentary majority with favourable legislative programming, and extensive advance policy development. The parliamentary progress of the bill was characterised by smooth passage and constructive scrutiny. Once enacted, the legislation was implemented smoothly and swiftly, though this did not prevent some unintended consequences, such as controversies over the Sewel convention and over the size of the Scottish parliament. The devolution scheme of the 1998 act enjoyed an extended honeymoon, with generally favourable political, financial and legal circumstances. However, recent years have seen the onset of more fluid and difficult times, which will test the robustness and viability of the 1998 act in the government of Scotland and of the United Kingdom.
Divided Loyalties: The European Communities Act 1972
Authors: NORTON PHILIP
Published: January 2011

UK membership of the European Communities (EC) was prompted by economic and political factors. It represented a novel constitutional departure; one that was contested. The proposal for membership created divisions between, and within, both main parties. Although both Houses voted overwhelmingly in support of the principle of the membership, the short bill to give legal effect in UK law to membership was bitterly contested, the government achieving the second reading of the bill through a vote of confidence. The bill was opposed consistently by the Labour opposition and dissident Conservative back benchers, though passage of the bill was achieved eventually, courtesy of Liberals and some abstaining Labour MPs, and without amendment. The act enabled the United Kingdom to become a member of the EC, with important consequences for the UK constitution, including creating a juridical dimension unparalleled since before the Glorious Revolution of 1688. Parliament has provided for its own legislation to be subordinate to that of the EC, while adapting to the new situation through the creation of committees to scrutinise European documents.
The Primary Photophysics of the Avena sativa Phototropin 1 LOV2 Domain Observed with Time‐resolved Emission Spectroscopy†
Authors: van Stokkum Ivo H. M. , Gauden Magdalena , Crosson Sean , van Grondelle Rienk , Moffat Keith , Kennis John T. M.
Published: January 2011

The phototropins are blue‐light receptors that base their light‐dependent action on the reversible formation of a covalent bond between a flavin mononucleotide (FMN) cofactor and a conserved cysteine in light, oxygen or voltage (LOV) domains. The primary reactions of the Avena sativa phototropin 1 LOV2 domain were investigated by means of time‐resolved and low‐temperature fluorescence spectroscopy. Synchroscan streak camera experiments revealed a fluorescence lifetime of 2.2 ns in LOV2. A weak long‐lived component with emission intensity from 600 to 650 nm was assigned to phosphorescence from the reactive FMN triplet state. This observation allowed determination of the LOV2 triplet state energy level at physiological temperature at 16600 cm−1. FMN dissolved in aqueous solution showed pH‐dependent fluorescence lifetimes of 2.7 ns at pH 2 and 3.9−4.1 ns at pH 3–8. Here, too, a weak phosphorescence band was observed. The fluorescence quantum yield of LOV2 increased from 0.13 to 0.41 upon cooling the sample from 293 to 77 K. A pronounced phosphorescence emission around 600 nm was observed in the LOV2 domain between 77 and 120 K in the steady‐state emission.
Jiddat al Harasis 422: A ureilite with an extremely high degree of shock melting
Authors: JANOTS Emilie , GNOS Edwin , HOFMANN Beda A. , GREENWOOD Richard C. , FRANCHI Ian A. , BISCHOFF Addi
Published: January 2011

Abstract–

The Jiddat al Harasis (JaH) 422 ureilite was found in the Sultanate of Oman; it is classified as a ureilitic impact melt breccia. The meteorite consists of rounded polycrystalline olivine clasts (35%), pores (8%), and microcrystalline matrix (57%). Clasts and matrix have oxygen isotopic values and chemical compositions (major and trace elements) characteristic of the ureilite group. The matrix contains olivine (Fo83–90), low‐Ca pyroxene (En84–92Wo0–5), augite (En71–56Wo20–31), graphite, diamond, Fe‐metal, sulfides, chromite, and felsic glass. Pores are partly filled by secondary Fe‐oxihydroxide and desert alteration products. Pores are surrounded by strongly reduced silicates. Clasts consist of fine‐grained aggregates of polygonal olivine. These clasts have an approximately 250 μm wide reaction rim, in which olivine composition evolves progressively from the core composition (Fo79–81) to the matrix composition (Fo84–87). Veins crossing the clasts comprise pyroxene, Fe‐oxihydroxide, C‐phases, and chromite. Clasts contain Ca‐, Al‐, and Cr‐rich glass along olivine grain boundaries (<1 μm wide). We suggest that a significant portion of JaH 422, including olivine and all the pyroxenes, was molten as a result of an impact. In comparison with other impact‐melted ureilites, JaH 422 shows the highest melt portion. Based on textural and compositional considerations, clasts and matrix probably originated from the same protolith, with the clasts representing relict olivine that survived, but was recrystallized in the impact melt. During the melt stage, the high availability of FeO and elevated temperatures controlled oxygen fugacity at values high enough to stabilize olivine with Fo∼83–87 and chromite. Along pores, high Mg# compositions of silicates indicate that in a late stage or after melt crystallization FeO became less available and fO2 conditions were controlled by C−CO + CO2.
Experimental investigation of the impact fragmentation of blocks embedded in regolith
Authors: DURDA Daniel D. , CHAPMAN Clark R. , CINTALA Mark J. , FLYNN George J. , STRAIT Melissa M. , MINNICK Anderson
Published: January 2011

Abstract– We present results of a set of impact experiments designed to examine the effects of impacts onto rocky blocks resting on and embedded within regoliths. The targets were approximately 500 g granodiorite blocks, struck with one‐eighth inch aluminum spheres at nominal speeds of approximately 5 km s−1. The granodiorite blocks were emplaced in 20–30 grade silica sand to simulate an asteroidal or lunar regolith; block burial depths ranged from resting flush on the surface to submerged completely below the surface. We observe a trend for largest remnant mass to increase with block burial depth. Documentary still image and high‐speed video of the resulting block fragments and surrounding regolith reveal new insights into the morphologies of blocks and secondary craters observed on asteroids like 433 Eros.
The habitual use of emotion regulation strategies in schizophrenia
Authors: Perry Yael , Henry Julie D. , Grisham Jessica R.
Published: January 2011

Objectives. Although emotion dysregulation is regarded as a core feature of schizophrenia, the use of specific regulatory strategies remains poorly understood. The aim of this study, therefore, was to investigate the habitual use of suppression, reappraisal, and acceptance in this population.

Methods. Thirty‐three individuals with schizophrenia and 36 matched controls completed self‐report measures examining emotion regulation and psychosocial functioning.

Results. No group differences were found in terms of use of suppression or reappraisal, but clinical participants reported using less acceptance. Further, greater use of acceptance was associated with better psychosocial outcomes.

Conclusions. Results highlight the potential utility of acceptance‐based interventions for comorbid psychopathology in schizophrenia.
Sampling-Based Stochastic Sensitivity Analysis Using Score Functions for RBDO Problems With Correlated Random Variables
Authors: Lee Ikjin , Choi K. K. , Noh Yoojeong , Zhao Liang , Gorsich David
Published: January 2011

This study presents a methodology for computing stochastic sensitivities with respect to the design variables, which are the mean values of the input correlated random variables. Assuming that an accurate surrogate model is available, the proposed method calculates the component reliability, system reliability, or statistical moments and their sensitivities by applying Monte Carlo simulation to the accurate surrogate model. Since the surrogate model is used, the computational cost for the stochastic sensitivity analysis is affordable compared with the use of actual models. The copula is used to model the joint distribution of the correlated input random variables, and the score function is used to derive the stochastic sensitivities of reliability or statistical moments for the correlated random variables. An important merit of the proposed method is that it does not require the gradients of performance functions, which are known to be erroneous when obtained from the surrogate model, or the transformation from X-space to U-space for reliability analysis. Since no transformation is required and the reliability or statistical moment is calculated in X-space, there is no approximation or restriction in calculating the sensitivities of the reliability or statistical moment. Numerical results indicate that the proposed method can estimate the sensitivities of the reliability or statistical moments very accurately, even when the input random variables are correlated.
Design, Construction and Evaluation of a Sun-Tracking System on a Mobile Structure
Authors: Mousazadeh Hossein , Keyhani Alireza , Javadi Arzhang , Mobli Hossein , Abrinia Karen , Sharifi Ahmad
Published: January 2011

Although using sun-trackers are not mandatory in PV systems, their application improves the efficiency and maximizes daily collected energy. To maximize collected energy from an on-board PV array, on a solar assist plug-in hybrid electric tractor (SAPHT) a sun-tracking system was designed and installed. Considering the mobile structure above the SAPHT, designing a time and date independent sun-tracker was desirable. Using four light dependent resistive sensors a sun-tracking system on a mobile structure was constructed and evaluated. Using the designed sun-tracking system, the experimental tests illustrated that 30% more energy was collected in comparison to that of the horizontally fixed mode. Only 1.8% of all maximized energy is consumed by actuators of the designed tracking system. However, the developed sun-tracking system is robust and inexpensive and showed acceptable performance during experimental tests.
Study on Air Accumulation and Influence on Flow Balance in Micro-Injection Molding
Authors: Cao Wei , Gan Shufeng , Ye Shubing , Li Qian , Shen Changyu
Published: January 2011

The conventional finite element method was employed to study the relationship between melt filling and air accumulation in micro-cavities. The variational equation for melt flow with slip boundary condition and air resistance was generalized based on Galerkin principle. To investigate the effect of air accumulation, the governing equation for air flow inside runner was established by dimensionless method. An iterative approach was proposed to solve the coupled melt flow problem and air flow problem. Numerical results show that air accumulation can affect the melt filling in micro-cavity, and closely depends on injection speed. Adjusting branch runner distribution can improve the flow balance, which was convinced by a real micro-part manufacturing.
Cavity Air Flow Behavior During Filling in Microinjection Molding
Authors: Griffiths C. A. , Dimov S. S. , Scholz S. , Tosello G.
Published: January 2011

Process monitoring of microinjection molding (μ-IM) is of crucial importance in understanding the effects of different parameter settings on the process, especially on its performance and consistency with regard to parts’ quality. Quality factors related to mold cavity air evacuation can provide valuable information about the process dynamics and also about the filling of a cavity by a polymer melt. In this paper, a novel experimental setup is proposed to monitor maximum air flow and air flow work as an integral of the air flow over time by employing a microelectromechanical system gas sensor mounted inside the mold. The influence of four μIM parameters, melt temperature, mold temperature, injection speed, and resistance to air evacuation, on two air flow-related output parameters is investigated by carrying out a design of experiment study. The results provide empirical evidences about the effects of process parameters on cavity air evacuation, and the influence of air evacuation on the part flow length.
Emission enhancement from nonpolar a-plane III-nitride nanopillar
Authors: Kim Byung-Jae , Jung Younghun , Mastro Michael A. , Hite Jennifer , Nepal Neeraj , Eddy Charles R. , Kim Jihyun
Published: January 2011

A nonpolar a-plane GaN-based light emitting structure was patterned by self-assembled SiO2 nanosphere lithography and subsequent inductively coupled plasma (ICP) etch to define an array of nanopillar light emitters. The photoluminescence (PL) intensity was enhanced by ∼110% after the anisotropic ICP etch, compared with an unprocessed sample, which is attributed to a reduction in wave-guiding effects in the thin film. Additionally, the anisotropic ICP etch caused minimal wavelength shift in the dominant 3.34 eV near-bandedge radiative transition. A subsequent photoelectrochemical (PEC) etch process of the a-plane GaN nanopillars preferentially etched the underlying n-type layers, leaving a wider p-type cap. The n-type layers wet-etched by recession of the N-polar (000-1) plane (perpendicular to the a-plane growth axis) via formation of the distinctive pyramid-shaped facets. The PL intensity was enhanced by ∼168% after ICP and PEC etching although the peak emission occurred at a lower energy. The combination of nanosphere lithography and ICP was highly effective in improving the light extraction efficiency in a-plane nonpolar GaN-based light emitting diodes.
Reduction of structural defects in a-plane GaN epitaxy by use of periodic hemispherical patterns in r-plane sapphire substrates
Authors: Wu Z. H. , Sun Y. Q. , Yin J. , Fang Y.-Y , Dai J. N. , Chen C. Q. , Wei Q. Y. , Li T. , Sun K. W. , Fischer A. M. , Ponce F. A.
Published: January 2011

Using hemisphere-shaped patterned r-plane sapphire substrates, high quality nonpolar (112¯0) a-plane gallium nitride (GaN) films have been obtained with superior structural characteristics to films grown on conventional (unpatterned) r-plane sapphire. This is evidenced by reduced x-ray rocking curve widths, smaller in-plane crystallographic anisotropy, and smoother surface morphology. Observations by transmission electron microscopy and cathodoluminescence reveal that the defect density is remarkably reduced in regions above the patterned hemispheres. The growth of a-plane GaN on the patterned substrates proceeds first by a relatively fast growth of the film on the flat surface region, and then a gradual lateral overgrowth over the protruding hemispheres, where the direct epitaxial growth is severely retarded.
Circular apertures for contact hole patterning in 193 nm immersion lithography
Authors: Tay C. J. , Quan C. , Ling M. L. , Chua G. S. , Tan S. K. , Lin Q.
Published: January 2011

Contact hole patterning has always been one of the most challenging issues in lithography. Conventional optical proximity correction (OPC) approach for contact hole patterning involves dimensional biasing, addition of serifs at corners, and insertion of subresolution enhancement features. However, as dimensions reduce, process window enhancement resulted from conventional OPC approach encounters limitations. In this paper, a new approach for contact hole patterning is investigated. Instead of using a square shape as target of a printed feature, a circular shape is proposed. Using the proposed method improvement in aerial image quality is achieved and the average improvement in the depth of focus is around 11%. In addition, the average normalized image logarithmic slope improvement for different pitches is found to be around 15%.
Protein expression analysis of ALCAM and CEACAM6 in breast cancer metastases reveals significantly increased ALCAM expression in metastases of the skin
Authors: Ihnen Maike , Kilic Ergin , Köhler Nadine , Löning Thomas , Witzel Isabell , Hagel Christian , Höller Sylvia , Kersten Jan F , Müller Volkmar , Jänicke Fritz , Milde-Langosch Karin
Published: January 2011

Aims

For prediction and understanding of underlying mechanisms of organ-specific metastases, various gene and protein expression signatures have been identified in primary breast carcinomas. These expression signatures often include several genes coding for adhesion molecules, such as activated leucocyte cell adhesion molecule (ALCAM/CD166) and carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6), both of which may play an important role in the development of distant metastases because of their adherent properties. Owing to their predominantly membranous localisation, they are also considered to have certain therapeutic potential. Apart from expression data obtained in the primary tumour, data for gene and protein expression patterns in distant breast cancer metastases are rare. Therefore this study focuses on analysing the distribution of ALCAM and CEACAM6 protein expression in breast cancer metastases from different sites.

Methods

Immunohistochemical staining for ALCAM and CEACAM6 in 117 breast cancer metastases derived from liver (n=24), lung (n=19), brain (n=21), bone (n=36) and skin (n=17) was performed.

Results

Immunoreactive scores (IRS) for ALCAM in all metastases except skin metastases ranged from 2.63 to 5.10 (membranous) and 2.79 to 3.67 (cytoplasmic), showing a positive correlation with each other (r=0.690, p<0.001). In skin metastases, ALCAM expression was significantly stronger (membranous IRS, 8.76; cytoplasmic IRS, 7.12; p<0.001). Mean staining intensity for CEACAM6 was IRS 3.88. No or weak CEACAM6 and ALCAM staining (IRS 0–3) was seen in 53% vs 27% of all metastases.

Conclusions

Compared with CEACAM6, ALCAM showed significantly stronger protein expression in breast cancer skin metastases compared with metastases in all other sites.
Reticulocyte population data in different erythropoietic states
Authors: Zini Gina , Di Mario Antonella , Garzia Mariagrazia , Bianchi Maria , d'Onofrio Giuseppe
Published: January 2011

Aims

To assess changes in reticulocyte impedance volume, conductivity and light scatter (reticulocyte population data or RPD) obtained with the volume, conductivity and laser light scatter (VCS) technology in healthy subjects and in different erythropoietic states.

Methods

Blood samples were analysed with the Beckman–Coulter LH750 system, using the VCS method, from a group of 40 healthy subjects and three groups of patients with different types of untreated or treated anaemia: 24 cases of iron deficiency at the time of diagnosis, 16 patients with iron deficiency anaemia during intravenous iron administration, and 57 patients with chronic kidney disease undergoing dialysis and administration of rHu-erythropoietin and intravenous iron.

Results

RPD data were reproducible. Average mean channels for volume were 50.9 for controls and 49.2, 55.7 and 64.0 for the three patient groups, respectively. Average mean channels for conductivity were 52.0 for controls and 59.8, 55.7 and 56.1 for the three patient groups. Average mean channels for light scatter were 108.4 for controls and 113.3, 117.3 and 128.2 for the three patient groups. SD data indicated increased dispersion in the patient groups.

Conclusion

When values in the patient groups are compared with reference values obtained in healthy controls, the main differences are found in impedance volume and light scatter, which were both increased in patients with stimulated erythropoiesis. These data indicate the opportunity to further evaluate the clinical usefulness of RPD in haematological diseases.
AMPLITUDES FOR gg→VV′ AND THEIR HIGH ENERGY SUSY CONSTRAINTS
Authors: GOUNARIS G. J. , LAYSSAC J. , RENARD F. M.
Published: January 2011

We study how the property of asymptotic helicity conservation (HCns), expected for any 2-to-2 process in the minimal supersymmetric model (MSSM), is realized in the processes gg →γγ, γZ, ZZ, W+W-, at one-loop electroweak order and very high energies. The violation of this property for the same process in the standard model (SM) is also shown. This strengthens the claim that HCns is specific to the renormalizable SUSY model, and not generally valid in the SM. HCns strongly reduces the number of nonvanishing 2-to-2 amplitudes at asymptotic energies in the MSSM.
A NEW PHYSICAL STATE FOR DE SITTER LINEAR GRAVITY
Authors: DEHGHANI M.
Published: January 2011

Based on conformal invariance and using Dirac's six-cone formalism, a new conformally invariant physical field equation for de Sitter (dS) linear gravity has been obtained, which corresponds to one of the unitary irreducible representations of the dS group and is denoted by [Formula: see text] in the sense of discrete series. Using ambient space notations, it has been shown that the solution to this new field equation can be written as the multiplication of a generalized symmetric polarization tensor of rank 2 and a massless conformally coupled scalar field in dS space–time. The physical tensor two-point function has been calculated in terms of the conformally coupled scalar two-point function in the ambient space formalism. It has been expressed in terms of dS intrinsic coordinates from its ambient space counterpart, which is dS-invariant and free of any divergences.
BIG BANG NUCLEOSYNTHESIS WITH A CONSTANT VACUUM ENERGY MOTIVATED BY CYCLIC COSMOLOGY
Authors: KALITA S. , DUORAH H. L. , DUORAH K.
Published: January 2011

Abundances of primordial deuterium, [Formula: see text] and helium, Yp, are examined by modifying the early universe expansion rate and hence the time–temperature relation, including a constant vacuum energy motivated by the cyclic scenario of brane cosmology. Enhancement of abundances with respect to standard BBN prediction is found. Rapid expansion leads to early freeze-out of weak interaction and hence to an enhanced neutron fraction at elevated freeze-out temperature, which in turn results in more helium. Nucleosynthesis at a much lower temperature (due to rapid expansion) faces a larger Coulomb barrier and leaves more deuterium behind, which is also implied by a lower baryon-to-photon ratio (η) as we increase the vacuum energy density. The change in the helium fraction agrees within orders of magnitudes with that found by the effect of more neutrino flavors on Yp. Elevation of the neutron fraction at freeze-out is revealed by decrease in the neutron–proton mass difference (Q) from 1.293 MeV to 1.279 MeV, which is consistent with the study of the influence of extra dimension size on BBN. The lowest Q value corresponds to the highest vacuum energy and also to the largest size of the extra dimension. The upper limit on vacuum energy density is found by estimating the contribution from nonbaryonic dark matter by using X-ray emission from galaxy clusters and taking a flat spatial geometry, which is found to be the cosmological constant (Λ) observed today, so that the abundances do not run beyond the observational upper bounds. The allowed range of ΩΛ, 0.786 ≤ ΩΛ≤ 0.844, makes Ypand [Formula: see text] lie within the observational upper bounds, which yields a Big Bang equivalence of the Λ universe. This is expected to further motivate the cyclic scenario, which incorporates a small and constant vacuum energy density tied to spacetime.
SPACE–TIME SINGULARITIES IN STRING AND ITS LOW DIMENSIONAL EFFECTIVE THEORY
Authors: SHARMA PREET , TZIOLAS ANDREAS , WANG ANZHONG , WU ZHONG CHAO
Published: January 2011

Space–time singularities are studied in both the (D+d)-dimensional string theory and its D-dimensional effective theory, obtained by the Kaluza–Klein compactification. It is found that space–time singularities in the low dimensional effective theory may or may not remain after lifted to the (D+d)-dimensional string theory, depending on particular solutions. It is also found that there exist cases in which space–time singularities appearing in high/low dimensional space–times do not necessarily happen on the same surfaces.
PROPAGATORS OF GENERALIZED SCHRÖDINGER EQUATIONS RELATED BY HIGHER-ORDER SUPERSYMMETRY
Authors: POZDEEVA EKATERINA , SCHULZE-HALBERG AXEL
Published: January 2011

We construct explicit integral relations between propagators of generalized Schrödinger equations that are linked by higher-order supersymmetry. Our results complement and extend the findings obtained in J. Phys. A40, 10557 (2007) for the conventional Schrödinger equation.
CHIRAL LOGARITHMIC QUARK MODEL OF N AND Δ WITH AN A-TERM IN THE MEAN-FIELD APPROXIMATION
Authors: ABU-SHADY M.
Published: January 2011

The A-term is included in the logarithmic quark sigma model, which is based on chiral symmetry and its spontaneous breaking. We investigate the consequences of this term and its relevance to baryon properties. The field equations have been solved in the mean-field approximation for the hedgehog baryon state. We found that including the A-term in the logarithmic quark model leads to lower energies of the nucleon and delta masses and reduces the values of the sigma commutator σπN(0), proton μp(N), and neutron μn(N) of the magnetic moments. This indicates that the inclusion of the A-term improves the calculated nucleon properties in comparison with previous work and other models.
EMBEDDING THEOREMS FOR CERTAIN ANISOTROPIC BESOV–MORREY SPACES
Authors: KHIDR SHABAN , YEIHIA KHALEAL
Published: January 2011

For smooth functions defined on a bounded domain satisfying the weak σ-horn condition, integral representations in terms of their derivatives and their differences are introduced. These representations are employed to prove embedding theorems in the [Formula: see text]-function spaces, [Formula: see text] with [Formula: see text] for all i = 0, 1, 2, …, n and j = 1, 2, …, n.
DIRECT QUANTIZATION OF EQUATIONS OF MOTION: FROM CLASSICAL DYNAMICS TO TRANSITION AMPLITUDES VIA STRINGS
Authors: KOCHAN DENIS
Published: January 2011

New method of quantization is presented. It is based on classical Newton–Lagrange equations of motion (representing the fundamental physical law of mechanics) rather than on their traditional Lagrangian and/or Hamiltonian precursors. It is shown that classical dynamics is governed by canonical two-form Ω, which embodies kinetic energy and forces acting within the system. New type of variational principle employing differential two-form Ω and "umbilical strings" is introduced. The Feynman path integral over histories of the system is then rearranged to "umbilical world-sheet" functional integral in accordance with the proposed variational principle. In the case of potential-generated forces, world-sheet approach reduces to the standard quantum mechanics. As an example Quantum Mechanics with friction is analyzed in detail.
THE HAMILTON–JACOBI FORMALISM FOR HIGHER-ORDER FIELD THEORIES
Authors: VITAGLIANO LUCA
Published: January 2011

We extend the geometric Hamilton–Jacobi formalism for Hamiltonian mechanics to higher-order field theories with regular Lagrangian density. We also investigate the dependence of the formalism on the Lagrangian density in the class of those yielding the same Euler–Lagrange equations.
ROUTH REDUCTION FOR SINGULAR LAGRANGIANS
Authors: LANGEROCK BAVO , LÓPEZ MARCO CASTRILLÓN
Published: January 2011

This paper concerns the Routh reduction procedure for Lagrangians systems with symmetry. It differs from the existing results on geometric Routh reduction in the fact that no regularity conditions on either the Lagrangian L or the momentum map JL are required apart from the momentum being a regular value of JL. The main results of this paper are: the description of a general Routh reduction procedure that preserves the Euler–Lagrange nature of the original system and the presentation of a presymplectic framework for Routh reduced systems. In addition, we provide a detailed description and interpretation of the Euler–Lagrange equations for the reduced system. The proposed procedure includes Lagrangian systems with a non-positively definite kinetic energy metric.
Semantics of transactional memory and automatic mutual exclusion
Authors: Abadi Martín , Birrell Andrew , Harris Tim , Isard Michael
Published: January 2011

Software Transactional Memory (STM) is an attractive basis for the development of language features for concurrent programming. However, the semantics of these features can be delicate and problematic. In this article we explore the trade-offs semantic simplicity, the viability of efficient implementation strategies, and the flexibility of language constructs. Specifically, we develop semantics and type systems for the constructs of the Automatic Mutual Exclusion (AME) programming model; our results apply also to other constructs, such as atomic blocks. With this semantics as a point of reference, we study several implementation strategies. We model STM systems that use in-place update, optimistic concurrency, lazy conflict detection, and rollback. These strategies are correct only under nontrivial assumptions that we identify and analyze. One important source of errors is that some efficient implementations create dangerous “zombie” computations where a transaction keeps running after experiencing a conflict; the assumptions confine the effects of these computations.
Mechanically verified proof obligations for linearizability
Authors: Derrick John , Schellhorn Gerhard , Wehrheim Heike
Published: January 2011

Concurrent objects are inherently complex to verify. In the late 80s and early 90s, Herlihy and Wing proposed
linearizability
as a correctness condition for concurrent objects, which, once proven, allows us to reason about concurrent objects using pre- and postconditions only. A concurrent object is linearizable if all of its operations appear to take effect instantaneously some time between their invocation and return.

In this article we define simulation-based proof conditions for linearizability and apply them to two concurrent implementations, a lock-free stack and a set with lock-coupling. Similar to other approaches, we employ a theorem prover (here, KIV) to mechanize our proofs. Contrary to other approaches, we also use the prover to mechanically check that our proof obligations actually guarantee linearizability. This check employs the original ideas of Herlihy and Wing of verifying linearizability via
possibilities
.
Crowdsourcing for search evaluation
Authors: Carvalho Vitor R. , Lease Matthew , Yilmaz Emine
Published: January 2011

The Crowdsourcing for Search Evaluation Workshop (CSE 2010) was held on July 23, 2010 in Geneva, Switzerland, in conjunction with the 33rd Annual ACM SIGIR Conference. The workshop addressed the latest advances in theory and empirical methods in crowdsourcing for search evaluation, as well as novel applications of crowdsourcing for evaluating search systems. Three invited talks were presented, along with seven refereed papers. Proceedings from the workshop, along with presentation slides, have been made available online.
Report on the SIGIR 2010 workshop on the simulation of interaction
Authors: Azzopardi Leif , Järvelin Kalervo , Kamps Jaap , Smucker Mark D.
Published: January 2011

All search in the real-world is inherently interactive. Information retrieval (IR) has a firm tradition of using simulation to evaluate IR systems as embodied by the Cranfield paradigm. However, to a large extent, such system evaluations ignore user interaction. Simulations provide a way to go beyond this limitation. With an increasing number of researchers using simulation to evaluate interactive IR systems, it is now timely to discuss, develop and advance this powerful methodology within the field of IR. During the SimInt 2010 workshop around 40 participants discussed and presented their views on the simulation of interaction. The main conclusion and general consensus was that simulation offers great potential for the field of IR; and that simulations of user interaction can make explicit the user and the user interface while maintaining the advantages of the Cranfield paradigm.
The 8th workshop on large-scale distributed systems for information retrieval (LSDS-IR'10)
Authors: Blanco Roi , Cambazoglu B. Barla , Lucchese Claudio
Published: January 2011

The size of theWeb as well as user bases of search systems continue to grow exponentially. Consequently, providing subsecond query response times and high query throughput become quite challenging for large-scale information retrieval systems. Distributing different aspects of search (e.g., crawling, indexing, and query processing) is essential to achieve scalability in large-scale information retrieval systems. The 8th Workshop on Large-Scale Distributed Systems for Information Retrieval (LSDS-IR'10) has provided a venue to discuss the current research challenges and identify new directions for distributed information retrieval. The workshop contained two industry talks as well as six research paper presentations. The hot topics in this year's workshop were collection selection architectures, application of MapReduce to information retrieval problems, similarity search, geographically distributed web search, and optimization techniques for search efficiency.
EVIA 2010
Authors: Webber William , Sakai Tetsuya , Sanderson Mark
Published: January 2011

The Third International Workshop on Evaluating Information Access (EVIA 2010) was held at the National Institute of Informatics, Tokyo, on June 15th, 2010. Themes were evaluation depth; the management of collaborative experiments; result diversity; and user studies.
Personalizing information retrieval using task stage, topic knowledge, and task products
Authors: Liu Jingjing
Published: January 2011

Personalization of information retrieval tailors search towards individual users to meet their particular information needs by taking into account information about users and their contexts, often through implicit sources of evidence such as user behaviors and contextual factors. The current study looks particularly at users' dwelling behavior, measured by the time that they spend on documents; and several contextual factors: the stage of users' work tasks, task type, users' knowledge of task topics, to explore whether or not taking account of task stage, task type, and topic knowledge could help predict document usefulness from the time that users spend on the documents. This study also investigates whether or not expanding queries with important terms extracted from task products and useful pages improves search performance. To these ends, a controlled lab experiment was conducted with 24 student participants, each coming three times in a two-week period to work on three subtasks in a general work task. Data were collected by logging software that recorded user-system interaction and questionnaires that elicited users' background information and perceptions on a number of aspects. Observations in the study and examinations of the data found that the time users spent on documents could have three different types: total display time, total dwell time, and decision time, which had different roles in working as a reliable indicator of document usefulness. Task stage was found to help interpret certain types of time as reliable indicators of document usefulness in certain task types, so was topic knowledge, and the latter played a more significant role when both were available. This study contributes to a better understanding of how information seeking behaviors, specifically, time that users spend on documents, can be used as implicit evidence of document usefulness, as well as how contextual factors of task stage, topic knowledge, and task type can help interpret time as an indicator of usefulness. These findings have theoretical and practical implications for using behaviors and contextual factors in the development of personalization systems. Future studies are suggested on making use of these findings as well as research on related issues.
Proof of concept
Authors: Trieschnigg Dolf
Published: January 2011

In this thesis we investigate the possibility to integrate domain-specific knowledge into biomedical information retrieval (IR). Recent decades have shown a fast growing interest in biomedical research, reflected by an exponential growth in scientific literature. An important problem for biomedical IR is dealing with the complex and inconsistent terminology encountered in biomedical publications. Dealing with the terminology problem requires domain knowledge stored in terminological resources: controlled indexing vocabularies and thesauri. The integration of this knowledge is, however, far from trivial.

The first research theme investigates heuristics for obtaining word-based representations from biomedical text for robust retrieval. We investigated the effect of choices in document preprocessing heuristics on retrieval effectiveness. Document preprocessing heuristics such as stop word removal, stemming, and breakpoint identification and normalization were shown to strongly affect retrieval performance. An effective combination of heuristics was identified to obtain a word-based representation from text for the remainder of this thesis.

The second research theme deals with concept-based retrieval. We compared a word-based to a concept-based representation and determined to what extent a manual concept-based representation can be automatically obtained from text. Retrieval based on only concepts was demonstrated to be significantly less effective than word-based retrieval. This deteriorated performance could be explained by errors in the classification process, limitations of the concept vocabularies and limited exhaustiveness of the concept-based document representations. Retrieval based on a combination of word-based and automatically obtained concept-based query representations did significantly improve word-only retrieval.

In the third and last research theme we propose a cross-lingual framework for monolingual biomedical IR. In this framework, the integration of a concept-based representation is viewed as a cross-lingual matching problem involving a word-based and concept-based representation language. This framework gives us the opportunity to adopt a large set of established crosslingual information retrieval methods and techniques for this domain. Experiments with basic term-to-term translation models demonstrate that this approach can significantly improve word-based retrieval.

Directions for future work are using these concepts for communication between user and retrieval system, extending upon the translation models and extending CLIR-enhanced concept-based retrieval outside the biomedical domain.

Available online from http://purl.utwente.nl/publications/72481.
In search of the Why
Authors: Verberne Suzan
Published: January 2011

The problem of automatically answering natural language questions by pinpointing exact answers in a large text (web) corpus has been studied since the mid 1990s. Most research has been directed at answering factoid questions: questions that expect a short, clearly identifiable answer; usually a named entity such as a person name, location or year. In this dissertation, we have focused on the problem of answering why-questions (why-QA). Whyquestions require a different approach than factoid questions because their answers tend to be longer and more complex. Our main research question was: "What are the possibilities and limitations of an approach to why-QA that uses linguistic information in addition to text retrieval techniques?

We first experimented with a simple bag-of-words approach on a set of open-domain whyquestions and Wikipedia as answer corpus. With Lemur as retrieval engine and TF-IDF as ranking model, we were able to retrieve a correct answer passage in the top-10 for 45% of the questions. The most important limitation of the bag-of-words approach for why-QA is that the structure of the questions and the candidate answers is not taken into account. We studied a number of levels of linguistic information on both the side of the question and the side of the answer passage in order to find out which type of information is the most important for answering why-questions.

We implemented a re-ranking module that incorporates knowledge about the syntactic structure of why-questions and the document context of the answers. With this module, we were able to improve significantly over the already quite reasonable bag-of-words baseline. After we optimized the feature combination in a learning-to-rank set-up, our system reached an MRR of 0.35 with a success@10 score of 57%. These scores were reached with only eight overlap features, one of which was the baseline ranker TF-IDF and the others were based on linguistic information (e.g. question focus, cue words and WordNet Similarity) and document structure (e.g. document title and the position of the answer passage in the document).

For solving the remaining 43% of the questions, we found that more is needed than classic NLP. Our conclusion is that why-QA deserves renewed attention from the field of artificial intelligence.

The dissertation is available online at http://lands.let.ru.nl/~sverbern/.
Towards architecture independent metrics for multicore performance analysis
Authors: Kulkarni Milind , Pai Vijay , Schuff Derek
Published: January 2011

The prevalence of multicore architectures has made the performance analysis of multithreaded applications an intriguing area of inquiry. An understanding of locality effects and communication behavior can provide programmers with valuable information about performance bottlenecks and opportunities for optimization. Unfortunately, most performance analyses are architecture dependent, and hence insights gleaned from an application's behavior on one platform may not apply when the application is run on another. In this position paper, we argue that what is needed are architecture independent metrics that characterize the behavior of an application in a system-agnostic manner. Such metrics will allow a program's performance to be analyzed across a range of architectures without incurring the overhead of repeated profiling and analysis. We propose two specific analyses: multicore-aware reuse distance, which captures the locality properties of an application and communication analysis, which exposes the structure of communication in an application. We also discuss a number of applications of these analyses, in the domains of optimization, code restructuring and performance modeling.
LiveLab
Authors: Shepard Clayton , Rahmati Ahmad , Tossell Chad , Zhong Lin , Kortum Phillip
Published: January 2011

We present LiveLab, a methodology to measure real-world smartphone usage and wireless networks with a reprogrammable indevice logger designed for long-term user studies. We discuss the challenges of privacy protection and power impact in LiveLab and offer our solutions. We present an iPhone 3GS based deployment of LiveLab with 25 users intended for one year. Early results from the data collection so far highlight the unique strengths and potential of LiveLab. We have two objectives in this position paper. First, we demonstrate the feasibility and capability of LiveLab. By sharing our experience, we seek to advocate LiveLab as a network and user measurement methodology. Second, we present our preliminary findings, and seek feedback from the community regarding what data to collect.
Achieving energy savings and QoS in internet access routers
Authors: Lombardo Alfio , Panarello Carla , Schembra Giovanni
Published: January 2011

In order to provide high quality communications over a best-effort network, an alternative to complex QoS control procedures is represented by generously over-provisioning the network resources. This approach has guaranteed in the near past reasonably performance for many applications, but it implies a waste of energy that today is unsustainable. This paper proposes an autonomous measurement mechanism, named G-Router, to allow an access node in the Internet to align its power consumption to either the maximum capacity the user traffic requires, or the minimum available capacity in the network path between source and destination. Simulation results show that allowing access network nodes to adapt the switching and transmission resources to the minimum between the above values, the G-Router guarantees the maximum QoS while minimizing the energy consumption.
Apples-to-apples
Authors: Bianzino Aruna Prem , Raju Anand Kishore , Rossi Dario
Published: January 2011

Research on energy-efficiency of communication networks has already gained the attention of a broad research community. Specifically, we consider efforts towards improving environmental sustainability by making networks energyaware. An important step in this direction is establishing a comprehensive methodology for measuring and reporting the energy consumption of the network. In this work, we compare and contrast various energy-related metrics used in the recent literature, by means of a taxonomy definition, as well as through relevant case studies. We believe this to be a first necessary step towards the definition of a common framework for the performance evaluation of energy-aware networks.
LMS Strategies in Higher Education
Authors: Reed Daniel
Published: January 2011

Academic institutions understand the importance of cutting edge, comprehensive course offerings; and having a robust LMS makes all the difference in attracting and retaining students. Creating an LMS strategy is not only about picking the right vendor; institutions must also do their due diligence when it comes to updating or replacing their systems.
Mathematizing C++ concurrency
Authors: Batty Mark , Owens Scott , Sarkar Susmit , Sewell Peter , Weber Tjark
Published: January 2011

Shared-memory concurrency in C and C++ is pervasive in systems programming, but has long been poorly defined. This motivated an ongoing shared effort by the standards committees to specify concurrent behaviour in the next versions of both languages. They aim to provide strong guarantees for race-free programs, together with new (but subtle) relaxed-memory atomic primitives for high-performance concurrent code. However, the current draft standards, while the result of careful deliberation, are not yet clear and rigorous definitions, and harbour substantial problems in their details.

In this paper we establish a mathematical (yet readable) semantics for C++ concurrency. We aim to capture the intent of the current (`Final Committee') Draft as closely as possible, but discuss changes that fix many of its problems. We prove that a proposed x86 implementation of the concurrency primitives is correct with respect to the x86-TSO model, and describe our Cppmem tool for exploring the semantics of examples, using code generated from our Isabelle/HOL definitions.

Having already motivated changes to the draft standard, this work will aid discussion of any further changes, provide a correctness condition for compilers, and give a much-needed basis for analysis and verification of concurrent C and C++ programs.