bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiple intracranial space‐occupying lesions in a renal transplant recipient from an area endemic for tuberculosis (TB): TB vs. toxoplasmosis
Authors: Bagchi S. , Sachdev S.S. , Nalwa A. , Das C.J. , Sinha S. , Suri V. , Mahajan S. , Bhowmik D. , Agarwal S.
Published: July 2014

Renal transplant recipients may present with intracranial space‐occupying lesions (SOLs) due to infections as well as a post‐transplant lymphoproliferative disorder (PTLD). Here, we discuss a renal transplant recipient who presented with neurologic symptoms and magnetic resonance imaging (MRI) of the brain showed multiple focal SOLs. Tuberculosis (TB), toxoplasmosis, nocardiosis, fungal infections, and PTLD were considered in the differential diagnosis. MRI spectroscopy was suggestive of an infectious cause, such as toxoplasmosis or TB. Serologic tests using Toxoplasma were negative. A brain biopsy followed by immunohistochemical staining using Toxoplasma antibody demonstrated multiple intravascular cysts of toxoplasma. This case highlights the diagnostic dilemma in an immunocompromised patient with multiple focal brain lesions, especially in areas where TB is endemic.
Poor appointment‐keeping behaviour among repeat blood donors and its relationship to the intent to donate again
Authors: Mousavi S. A. , Hermundstad B. , Kjustad Frøyland E.‐M. , Llohn A. H. , Knutsen T. R.
Published: July 2014

Background and objectives

Anecdotal evidence suggests that missed donation appointments among repeat whole‐blood donors are associated with decreased likelihood of future blood donation. This study sought to examine the relationship between missed donation appointments and intention to donate again among repeat whole‐blood donors and to examine whether demographic variables are related to appointment‐keeping behaviour.

Methods

During the period February–June 2013, telephone interviews were conducted with repeat donors who either did not show up for or cancelled their donation appointments on the day of the appointment. We asked them whether or not they wanted to schedule appointments for subsequent donations.

Results

Rates of missed donation appointments varied by age, but not gender. Although a statistically significant difference between male and female donors was not found with regard to willingness to donate again, female donors were more likely than male donors to call and cancel their appointment. Finally, compared with repeat donors who called and cancelled their appointment, no‐show donors were 2·5 times less likely to schedule appointments for subsequent donations (P < 0·001).

Conclusion

The results demonstrate that poor appointment‐keeping behaviour, and in particular no‐show behaviour, is significantly associated with decreased likelihood of future blood donation among repeat whole‐blood donors.
Evaluating Bias of Illumina-Based Bacterial 16S rRNA Gene Profiles
Authors: Kennedy Katherine , Hall Michael W. , Lynch Michael D. J. , Moreno-Hagelsieb Gabriel , Neufeld Josh D.
Published: July 2014

Massively parallel sequencing of 16S rRNA genes enables the comparison of terrestrial, aquatic, and host-associated microbial communities with sufficient sequencing depth for robust assessments of both alpha and beta diversity. Establishing standardized protocols for the analysis of microbial communities is dependent on increasing the reproducibility of PCR-based molecular surveys by minimizing sources of methodological bias. In this study, we tested the effects of template concentration, pooling of PCR amplicons, and sample preparation/interlane sequencing on the reproducibility associated with paired-end Illumina sequencing of bacterial 16S rRNA genes. Using DNA extracts from soil and fecal samples as templates, we sequenced pooled amplicons and individual reactions for both high (5- to 10-ng) and low (0.1-ng) template concentrations. In addition, all experimental manipulations were repeated on two separate days and sequenced on two different Illumina MiSeq lanes. Although within-sample sequence profiles were highly consistent, template concentration had a significant impact on sample profile variability for most samples. Pooling of multiple PCR amplicons, sample preparation, and interlane variability did not influence sample sequence data significantly. This systematic analysis underlines the importance of optimizing template concentration in order to minimize variability in microbial-community surveys and indicates that the practice of pooling multiple PCR amplicons prior to sequencing contributes proportionally less to reducing bias in 16S rRNA gene surveys with next-generation sequencing.
Dynamic metabolomic responses of Escherichia coli to nicotine stress
Authors: Ding Lijian , Chen Juanjuan , Zou Jianding , Zhang Limin , Ye Yangfang
Published: July 2014

Previously, we reported the metabolic responses of Pseudomonas sp. strain HF-1, a nicotine-degrading bacterium, to nicotine stress. However, the metabolic effects of nicotine on non-nicotine-degrading bacteria that dominate the environment are still unclear. Here, we have used nuclear magnetic resonance based metabolomics in combination with multivariate data analysis methods to comprehensively analyze the metabolic changes in nicotine-treated Escherichia coli. Our results showed that nicotine caused the changes of energy-related metabolism that we believe are due to enhanced glycolysis and mixed acid fermentation as well as inhibited tricarboxylic acid cycle activity. Furthermore, nicotine resulted in the alteration of choline metabolism with a decreased synthesis of betaine but an increased production of dimethylamine. Moreover, nicotine caused a decrease in amino acid concentration and an alteration of nucleotide synthesis. We hypothesize that these changes caused the decrease in bacterial cell density observed in the experiment. These findings provide a comprehensive insight into the metabolic response of E. coli to nicotine stress. Our study highlights the value of metabolomics in elucidating the metabolic mechanisms of nicotine action.
Drinfeld center of planar algebra
Authors: Das Paramita , Ghosh Shamindra Kumar , Gupta Ved Prakash
Published: July 2014

We introduce fusion, contragradient and braiding of Hilbert affine representations of a subfactor planar algebra P (not necessarily having finite depth). We prove that if N ⊂ M is a subfactor realization of P, then the Drinfeld center of the N–N-bimodule category generated byNL2(M)M, is equivalent to the category of Hilbert affine representations of P satisfying certain finiteness criterion. As a consequence, we prove Kevin Walker's conjecture for planar algebras.
EFFECTS OF QUANTITATIVE EASING ON ASIA: CAPITAL FLOWS AND FINANCIAL MARKETS
Authors: CHO DONGCHUL , RHEE CHANGYONG
Published: July 2014

This paper studies the effects of US quantitative easing (QE) on Asia by examining capital flows and financial markets. After the global financial crisis (GFC), Asian economies with more open and developed capital markets experienced greater swings in capital inflows. In particular, large capital flows manifest more in portfolio investment and other investment such as bank loans than in foreign direct investment. Empirical analysis shows QE, QE1 in particular, significantly contributed to the rebounding of capital inflows to the region after the onset of the crisis by lowering domestic yield rates as well as CDS premiums. Although the currency value responses differed across countries, it appears that economies with stable exchange rates roughly coincide with those in which house prices have been rising, suggesting that monetary easing of advanced countries have affected Asian countries through either appreciation of currency values or increases in the prices of housing.
THE RELATIONSHIP BETWEEN EMPLOYMENT AND EARNINGS IN SINGAPORE: 1991–2012
Authors: TAN G. K. RANDOLPH
Published: July 2014

Since its formation in 1972 under the leadership of its founding chairman, Professor Lim Chong Yah, the NWC has been a major force in ensuring the stability of the labor market. A key recommendation which the NWC pushed for as a means of saving jobs in the recessions has been the reduction of the cost of labor to employers. The underlying assumption was that the reaction of demand to reduced labor costs would be large enough to justify such an approach. The main aim of this paper is to derive estimates of the elasticity of demand for labor using a suitable time-series econometric approach. The estimates imply that the elasticity of demand for labor in Singapore is less than but close to being unitary in magnitude.
UNIQUELY SINGAPORE'S BUDGETARY SYSTEM AND SOCIAL PROTECTION FINANCING SCHEMES
Authors: CHIA NGEE CHOON
Published: July 2014

This paper examines Singapore's fiscal position and its unique way of financing targeted welfare programs. We examine how reserves are accumulated through fiscal discipline during times of phenomenal economic growth in Singapore and when Singapore was enjoying demographic dividend. The existence of the large accumulated reserves has resulted in particular features of the Singapore's budgetary process, such as fiscal rules, which govern the utilization of revenues from the reserves. Innovative budget implementation, such as Block Budgeting, has helped Singapore to ensure fiscal sustainability. The accumulation of reserves throughout its economic history has afforded Singapore a unique way to fund social protection through special transfers and funds, without having to raise taxes.
HOUSING POLICIES IN SINGAPORE: EVALUATION OF RECENT PROPOSALS AND RECOMMENDATIONS FOR REFORM
Authors: PHANG SOCK-YONG , LEE DAVID , CHEONG ALAN , PHOON KOK-FAI , WEE KAROL
Published: July 2014

The Singapore housing market is unusual in its high homeownership rate, the dominance of HDB housing, and the extensive intervention of the government in regulating housing supply and demand in both the HDB and private housing sectors. Recent rapid population increases in a low interest rate and high global liquidity environment has resulted in accelerated house prices increases in Singapore. Earlier this year, the government launched "Our Singapore Conversation" of which discussion on housing policies constitutes one major component. This "conversation" comes in the wake of several consecutive rounds of measures to stabilize housing prices using various instruments. This paper evaluates the main policy changes proposed and makes recommendations for housing market reforms: (i) the government need to clarify goals of housing policies and make available more detailed data on the foreign component of our population for better analysis of housing markets; (ii) the housing supply regime should target an overall effective vacancy rate that encompasses both the Housing and Development Board (HDB) and private sector; (iii) policy makers need to monitor carefully excess demand indicators for housing in addition to housing affordability indicators over the entire spectrum of incomes and household types; (iv) housing REITs should be established to provide an alternative investment option as well as to develop an efficient and affordable rental sector; and (v) in addition to macroprudential measures, owner-occupancy requirements and fiscal measures such as stamp duties and property taxes could be further utilized to reduce the foreign demand for Singapore housing and real estate.
INTO THE AGE OF NON-ECONOMICS
Authors: MOELLER JOERGEN OERSTROEM
Published: July 2014

Most economic concepts such as the market, competition, flexibility, pricing of production factors and consumption theory no longer reflect the reality of the contemporary situation. The current economic model and political system form a synthesis of fiduciary economics and privilege political systems. The exponential rise in material wealth amassed over the industrial age is unsustainable when figuring in the availability of resources. Even more interesting is how it may run counter to human instincts, our gene structure, and how the mindset and behavioral pattern are forged. As the economy and society evolves, combining in-depth knowledge across various disciplines is crucial to furthering our understanding of the world.
Electron systems out of equilibrium: Nonequilibrium Green's function approach
Authors: Špička Václav , Velický Bedřich , Kalvová Anděla
Published: July 2014

This review deals with the state of the art and perspectives of description of nonequilibrium many-body systems using the nonequilibrium Green's function (NGF) method. The basic aim is to describe time evolution of the many-body system from its initial state over its transient dynamics to its long time asymptotic evolution. First, we discuss basic aims of transport theories to motivate the introduction of the NGF techniques. Second, this article summarizes the present view on construction of the electron transport equations formulated within the NGF approach to nonequilibrium. We discuss incorporation of complex initial conditions to the NGF formalism, and the NGF reconstruction theorem, which serves as a tool to derive simplified kinetic equations. Three stages of evolution of the nonequilibrium, the first described by the full NGF description, the second by a non-Markovian generalized master equation and the third by a Markovian master equation will be related to each other.
Numerical study of carbon nanotube field effect transistors in presence of carbon–carbon third nearest neighbor interactions
Authors: Naderi Ali
Published: July 2014

In this paper, for the first time, we have used a more precise Hamiltonian matrix based on first nearest neighbor (1NN) and third nearest neighbor (3NN) carbon–carbon interactions to simulate carbon nanotube field effect transistors (CNTFETs). By taking the interactions with more distant neighbors into account, an improvement in tight-binding picture is gained. A self-consistent solution of Schrodinger equation based on nonequilibrium Green's function (NEGF) formalism coupled to a two-dimensional Poisson's equation for treating the electrostatics of the device has been employed to simulate CNTFETs. A tight-binding Hamiltonian with an atomistic (pz orbitals) mode space basis in the ballistic limits has been used to describe the carbon nanotube (CNT) region. Simulations show that in the presence of 3NN, the energy bandgap of the CNT decreases and consequently the simulated device has lower threshold voltage compared to a simulated device with just 1NN. Short channel effects study demonstrates that neglecting 3NN underestimates the subthreshold swing and overestimates ON/OFF current ratio. All these investigations show that for simulating a CNTFET more precisely, the 3NN interactions can be taken into account in addition to the 1NN.
Laser enhanced RKKY interaction in nanorings
Authors: Feng Peng , Yin Chunyu
Published: July 2014

The conduction electrons can deliver an indirect exchange interaction, namely RKKY interaction, between impurities dissolved in nonmagnetic metals or semiconductors by the interaction between the conduction electron spins and localized impurity spins. In two- and three-dimensional systems this interaction is very weak when the separation of impurities is large enough. However, an unexpected result exists in quantum rings. In this work we find that the laser can effectively enhance RKKY interaction in quantum rings on certain conditions, and there is a critical width of keeping this effect for the tube-like nanorings. As a possible application of this effect, it would provide a mechanism of realizing quantum communication by magnetic impurities.
A ± 0.2 V, 0.12 μW CCTA USING VTMOS AND AN APPLICATION FRACTIONAL-ORDER UNIVERSAL FILTER
Authors: COMEDANG TADA , INTANI PATTNA
Published: July 2014

In this paper, a variable threshold voltage metal oxide semiconductor (VTMOS) field effect transistor is used to improve an ultra-low voltage, ultra-low power current conveyor transconductance amplifier (CCTA). To achieve the desired result, an analytical subthreshold VTMOS model is used. Designs that utilize the TSMC 0.18 μm technology are verified using PSPICE simulation. The power consumption is simply 0.12 μW at a ± 0.2 V supply voltage. The proposed CCTA is synthesized using fractional-order (FO) universal filters that can simultaneously realise low pass (LP), high pass (HP) and bandpass (BP) responses with independent control of quality factor and pole frequency by transconductances (gm). Moreover, the circuit has low input and high output impedance which would be an ideal choice for cascading in current-mode circuit. The FO filters are constructed using two FO capacitors of orders α and β (0 < α, β ≤ 1). The FO filters provide improved performance in terms of pole frequency compared with conventional-order filters. The filter has a low power consumption of 0.71 μW at a ± 0.2 V supply voltage. The validity of the proposed filter is verified through PSPICE simulations.
Comparative study of the energy dependent and independent two-nucleon interactions — A supersymmetric approach
Authors: Laha U. , Bhoi J.
Published: July 2014

By exploiting supersymmetry inspired factorization method nucleon–nucleon (n–n) potentials, both energy dependent and independent, in the partial waves 1P1 and 3P1 are generated by judicious use of appropriate ground state wave functions and interactions. The energy independent Hulthen and energy dependent equivalent local Yamaguchi potentials and their corresponding S-wave functions are used as the starting point of our calculation. The scattering phase shifts are computed for the constructed potentials through Phase Function Method (PFM) and compared with the standard results to examine the merit of our approach to the problem.
THERMAL SHOCK BEHAVIOR OF AIR PLASMA SPRAYEDCoNiCrAlY/YSZTHERMAL BARRIER COATINGS
Authors: LIU ZI WEI , WU WEI , HUA JIA JIE , LIN CHU CHENG , ZHENG XUE BIN , ZENG YI
Published: July 2014

The structural changes and failure mechanism of thermal barrier coatings (TBCs) during thermal shock cycling were investigated. TBCs consisting of CoNiCrAlY bond coat and partially yttria-stabilized zirconia (YSZ) top coat were deposited by atmospheric plasma spraying (APS) on a nickel-based alloy substrate and its thermal shock resistance performance was evaluated. TBCs were heated at 1100°C for 15 min followed by cold water quenching to ambient temperature. Microstructural evaluation and elemental analysis of TBCs were performed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), respectively. The crack features of YSZ coatings in TBCs during thermal shock cycling, including those of horizontal (parallel to the substrate) and vertical cracks (perpendicular to the substrate), were particularly investigated by means of SEM and image analysis. Results show that horizontal and vertical cracks have different influences on the thermal shock resistance of the coatings. Horizontal cracks that occur at the interface of YSZ and thermally growth oxidation (TGO) cause partial or large-area spalling of coatings. When vertical and horizontal cracks encounter, network segments are formed which lead to partial spalling of the coatings.
The Formal Semantics of a Domain-Specific Modeling Language for Semantic Web Enabled Multi-Agent Systems
Authors: Getir Sinem , Challenger Moharram , Kardas Geylani
Published: July 2014

Development of agent systems is without question a complex task when autonomous, reactive and proactive characteristics of agents are considered. Furthermore, internal agent behavior model and interaction within the agent organizations become even more complex and hard to implement when new requirements and interactions for new agent environments such as the Semantic Web are taken into account. We believe that the use of both domain specific modeling and a Domain-specific Modeling Language (DSML) may provide the required abstraction and support a more fruitful methodology for the development of Multi-agent Systems (MASs) especially when they are working on the Semantic Web environment. Although syntax definition based on a metamodel is an essential part of a modeling language, an additional and required part would be the determination and implementation of DSML constraints that constitute the (formal) semantics which cannot be defined solely with a metamodel. Hence, in this paper, formal semantics of a MAS DSML called Semantic Web enabled Multi-agent Systems (SEA_ML) is introduced. SEA_ML is a modeling language for agent systems that specifically takes into account the interactions of semantic web agents with semantic web services. What is more, SEA_ML also supports the modeling of semantic agents from their internals to MAS perspective. Based on the defined abstract and concrete syntax definitions, we first give the formal representation of SEA_ML's semantics and then discuss its use on MAS validation. In order to define and implement semantics of SEA_ML, we employ Alloy language which is declarative and has a strong description capability originating from both relational and first-order logic in order to easily define complex structures and behaviors of these systems. Differentiating from similar contributions of other researchers on formal semantics definition for MAS development languages, SEA_ML's semantics, presented in this paper, defines both static and dynamic aspects of the interaction between software agents and semantic web services, in addition to the definition of the semantics already required for agent internals and MAS communication. Implementation with Alloy makes definition of SEA_ML's semantics to include relations and sets with a simple notation for MAS model definitions. We discuss how the automatic analysis and hence checking of SEA_ML models can be realized with the defined semantics. Design of an agent-based electronic barter system is exemplified in order to give some flavor of the use of SEA_ML's formal semantics. Lessons learned during the development of such a MAS DSML semantics are also reported in this paper.
L-band multi-wavelength Brillouin–Raman fiber laser utilizing the reverse-S-shaped section
Authors: Ahmad Hambali N. A. M. , Ali Toor M. , Yusoff Z. , Ajiya M.
Published: July 2014

In this paper, we experimentally demonstrated multi-wavelength Brillouin–Raman fiber laser that operates in the L-band wavelength region. The laser structure utilizes the reverse-S-shaped technique. 35 output Brillouin Stokes signals were generated at the injection of 6.3 mW of Brillouin pump power at wavelength of 1580 nm into the laser cavity together with a Raman pump power of 891.25 mW. The generated output Brillouin Stokes signals are rigidly separated by 0.08 nm (10 GHz). The structure also provides a high tuning range of 25 nm, from 1570 nm to 1595 nm at the injection of 6.3 mW of Brillouin pump signal power with a Raman pump signal power of 795.3 mW. The generated Brillouin Stokes signals also have an average peak power of 1.11 mW. Highest optical signal-to-noise ratio of 21 dB was obtained at Brillouin pump wavelength of 1595 nm.
ORGANIC SPINTRONICS: PAST, PRESENT AND FUTURE
Authors: LV XIAO-RONG , LIANG SHI-HENG , TAO LING-LING , HAN XIU-FENG
Published: July 2014

Organic spintronics, extended the conventional spintronics with metals, oxides and semiconductors, has opened new routes to explore the important process of spin-injection, transport, manipulation and detection, holding significant promise of revolutionizing future spintronic applications in high density information storage, multi-functional devices, seamless integration, and quantum computing. Here we survey this fascinating field from some new viewpoints on research hotspots and emerging trends. The main achievements and challenges arising from spin injection and transport, in organic materials are highlighted, as well as prospects of novel organic spintronic devices are also emphasized.
Middle to Late Pleistocene radiolarian biostratigraphy in the water-mixed region of the Kuroshio and Oyashio currents, northeastern margin of Japan (JAMSTEC Hole 902-C9001C)
Authors: Matsuzaki Kenji M. , Suzuki Noritoshi , Nishi Hiroshi , Takashima Reishi , Kawate Yumiko , Sakaii Toyosaburo
Published: July 2014

Abstract. A continuous Quaternary sediment sequence was recovered from Hole 902-C9001C during the D/V Chikyu 2006 mission along the northeastern margin of Japan. The age and rate of deposition of this core were estimated using calcareous nannofossil biostratigraphy and oxygen isotope curves measured from benthic foraminifera (Uvigerina akitaensis) and dated from 740 ka to the present, a period that spanned the Brunhes normal polarity epoch. Sediment consisted of diatomaceous siltstone and contained an abundance of radiolarians. A total of 91 radiolarian species was found in the core, of which 74 were analysed. Of these radiolarian species, 36 demonstrated continuous stratigraphical distribution over the past 740 ka and 38 had shorter ranges of biostratigraphical interest. Three of the 38 species were determined to be novel and are described in the present study (Amphisphaera tanzhiyuani sp. nov., Schizodiscus japonicus sp. nov. and Siphonosphaera? paraphoros sp. nov.). Based on 17 radiolarian bioevents, including four datums which have been commonly used across a wide area of the North Pacific, the radiolarian sequence of this core was divided into 8 zones: Amphirhopalum virchowii Zone (613–740 ka), Spongaster tetras irregularis Zone (516–613 ka), Cyrtidosphaera reticulata Zone (357–516 ka), Spongurus cylindricus Zone (238–357 ka), Pterocanium depressum Zone (209–238 ka), Spongoliva ellipsoides Zone (131–209 ka), Ceratospyris problematica Zone (33–131 ka), and the Acanthodesmia vinculata Zone (0–33 ka).
Development of the freeze–thaw processing technique for disaggregation of indurated mudrocks and enhanced recovery of calcareous microfossils
Authors: Kennedy Alice E. , Coe Angela L.
Published: July 2014

Abstract. Microfossil extraction from indurated mudrocks is widely acknowledged as challenging, especially for foraminifera. Here we report development of the freeze–thaw extraction method through the addition of rapid heating, detergent and ultrasound stages. We use indurated mudrock samples from the Toarcian (Early Jurassic) of Yorkshire, UK to assess the effectiveness and develop the freeze–thaw method. We compare our results from freeze–thaw with those from standard foraminifera processing techniques, including the use of hydrogen peroxide. Processing by freeze–thaw increased the degree of mudrock disaggregation and resulted in no damage or dissolution of foraminifera. Following the freeze–thaw method with treatment in white spirit and sodium hexametaphosphate aided the separation of foraminifera from the disaggregated clays and was twice as efficient as pressure washing. Samples processed with hydrogen peroxide contained damaged microfossils and an under representation of delicate calcareous foraminifera. Many other studies of indurated mudrocks have used hydrogen peroxide to extract foraminifera, and this might have resulted in apparently barren intervals. The freeze–thaw method outlined here provides a low-cost, low-risk and successful method of disaggregating and extracting calcareous microfossils from indurated mudrocks. We anticipate our method may be relevant for other fossil groups and merits further development.
High-Performance Evaluation of Finite Element Variational Forms via Commuting Diagrams and Duality
Authors: Kirby Robert C.
Published: July 2014

We revisit the question of optimizing the construction and application of finite element matrices. By using commuting properties of the reference mappings and duality, we reorganize stiffness matrix construction and matrix-free application so that the bulk of the work can be done by optimized matrix multiplication libraries. We provide examples, including numerical experiments, with the Laplace and curl-curl operators as well as develop a general framework. Our techniques are applicable in general geometry and are not restricted to constant coefficient operators.
Fast Reverse-Mode Automatic Differentiation using Expression Templates in C++
Authors: Hogan Robin J.
Published: July 2014

Gradient-based optimization problems are encountered in many fields, but the associated task of differentiating large computer algorithms can be formidable. The operator-overloading approach to performing reverse-mode automatic differentiation is the most convenient for the user but current implementations are typically 10-35 times slower than the original algorithm. In this paper a fast new operator-overloading method is presented that uses the
expression template
programming technique in C++ to provide a compile-time representation of each mathematical expression as a computational graph that can be efficiently traversed in either direction. Benchmarking with four different numerical algorithms shows this approach to be 2.6--9 times faster than current operator-overloading libraries, and 1.3--7.7 times more efficient in memory usage. It is typically less than 4 times the computational cost of the original algorithm, although poorer performance is found for all libraries in the case of simple loops containing no mathematical functions. An implementation is freely available in the
Adept
C++ software library.
Incremental Text Indexing for Fast Disk-Based Search
Authors: Margaritis Giorgos , Anastasiadis Stergios V.
Published: July 2014

Real-time search requires to incrementally ingest content updates and almost immediately make them searchable while serving search queries at low latency. This is currently feasible for datasets of moderate size by fully maintaining the index in the main memory of multiple machines. Instead, disk-based methods for incremental index maintenance substantially increase search latency with the index fragmented across multiple disk locations. For the support of fast search over disk-based storage, we take a fresh look at incremental text indexing in the context of current architectural features. We introduce a greedy method called Selective Range Flush (SRF) to contiguously organize the index over disk blocks and dynamically update it at low cost. We show that SRF requires substantial experimental effort to tune specific parameters for performance efficiency. Subsequently, we propose the Unified Range Flush (URF) method, which is conceptually simpler than SRF, achieves similar or better performance with fewer parameters and less tuning, and is amenable to I/O complexity analysis. We implement interesting variations of the two methods in the Proteus prototype search engine that we developed and do extensive experiments with three different Web datasets of size up to 1TB. Across different systems, we show that our methods offer search latency that matches or reduces up to half the lowest achieved by existing disk-based methods. In comparison to an existing method of comparable search latency on the same system, our methods reduce by a factor of 2.0--2.4 the I/O part of build time and by 21--24% the total build time.
Algorithm 943
Authors: Erway Jennifer B. , Marcia Roummel F.
Published: July 2014

A MATLAB implementation of the Moré-Sorensen sequential (MSS) method is presented. The MSS method computes the minimizer of a quadratic function defined by a limited-memory BFGS matrix subject to a two-norm trust-region constraint. This solver is an adaptation of the Moré-Sorensen direct method into an L-BFGS setting for large-scale optimization. The MSS method makes use of a recently proposed stable fast direct method for solving large shifted BFGS systems of equations [Erway and Marcia 2012; Erway et al. 2012] and is able to compute solutions to any user-defined accuracy. This MATLAB implementation is a matrix-free iterative method for large-scale optimization. Numerical experiments on the CUTEr [Bongartz et al. 1995; Gould et al. 2003]) suggest that using the MSS method as a trust-region subproblem solver can require significantly fewer function and gradient evaluations needed by a trust-region method as compared with the Steihaug-Toint method.
Algorithm 944
Authors: Antonelli Laura , Corsaro Stefania , Marino Zelda , Rizzardi Mariarosaria
Published: July 2014

We present Talbot Suite, a C parallel software collection for the numerical inversion of Laplace Transforms, based onTalbot's method. It is designed to fit both single and multiple Laplace inversion problems, which arise in several application and research fields.

In our software, we achieve high accuracy and efficiency, making full use of modern architectures and introducing two different levels of parallelism: coarse and fine grained parallelism. They offer a reasonable tradeoff between accuracy, the main aspect for a few inversions, and efficiency, the main aspect for multiple inversions. To take into account modern high-performance computing architectures, Talbot Suite provides different software versions: an OpenMP-based version for shared memory machines and a MPI-based version for distributed memory machines. Moreover, oriented to hybrid architectures, a combined MPI/OpenMP-based implementation is provided too. We describe our parallel algorithms and the software organization. We also report some performance results. Our software includes sample programs to call the Talbot Suite functions from C and from MATLAB.
Foundations of Trust and Distrust in Networks
Authors: Qian Yi , Adali Sibel
Published: July 2014

Modeling trust in very large social networks is a hard problem due to the highly noisy nature of these networks that span trust relationships from many different contexts, based on judgments of reliability, dependability, and competence. Furthermore, relationships in these networks vary in their level of strength. In this article, we introduce a novel extension of structural balance theory as a foundational theory of trust and distrust in networks. Our theory preserves the distinctions between trust and distrust as suggested in the literature, but also incorporates the notion of relationship strength that can be expressed as either discrete categorical values, as pairwise comparisons, or as metric distances. Our model is novel, has sound social and psychological basis, and captures the classical balance theory as a special case. We then propose a convergence model, describing how an imbalanced network evolves towards new balance, and formulate the convergence problem of a social network as a Metric Multidimensional Scaling (MDS) optimization problem. Finally, we show how the convergence model can be used to predict edge signs in social networks and justify our theory through extensive experiments on real datasets.
Propagating Both Trust and Distrust with Target Differentiation for Combating Link-Based Web Spam
Authors: Zhang Xianchao , Wang You , Mou Nan , Liang Wenxin
Published: July 2014

Semi-automatic anti-spam algorithms propagate either trust through links from a good seed set (e.g., TrustRank) or distrust through inverse links from a bad seed set (e.g., Anti-TrustRank) to the entire Web. These kinds of algorithms have shown their powers in combating link-based Web spam since they integrate both human judgement and machine intelligence. Nevertheless, there is still much space for improvement. One issue of most existing trust/distust propagation algorithms is that only trust or distrust is propagated and only a good seed set or a bad seed set is used. According to Wu et al. [2006a], a combined usage of both trust and distrust propagation can lead to better results, and an effective framework is needed to realize this insight. Another more serious issue of existing algorithms is that trust or distrust is propagated in nondifferential ways, that is, a page propagates its trust or distrust score uniformly to its neighbors, without considering whether each neighbor should be trusted or distrusted. Such kinds of blind propagating schemes are inconsistent with the original intention of trust/distrust propagation. However, it seems impossible to implement differential propagation if only trust or distrust is propagated. In this article, we take the view that each Web page has both a trustworthy side and an untrustworthy side, and we thusly assign two scores to each Web page: T-Rank, scoring the trustworthiness of the page, and D-Rank, scoring the untrustworthiness of the page. We then propose an integrated framework that propagates both trust and distrust. In the framework, the propagation of T-Rank/D-Rank is penalized by the target's current D-Rank/T-Rank. In other words, the propagation of T-Rank/D-Rank is decided by the target's current (generalized) probability of being trustworthy/untrustworthy; thus a page propagates more trust/distrust to a trustworthy/untrustworthy neighbor than to an untrustworthy/trustworthy neighbor. In this way, propagating both trust and distrust with target differentiation is implemented. We use T-Rank scores to realize spam demotion and D-Rank scores to accomplish spam detection. The proposed Trust-DistrustRank (TDR) algorithm regresses to TrustRank and Anti-TrustRank when the penalty factor is set to 1 and 0, respectively. Thus TDR could be seen as a combinatorial generalization of both TrustRank and Anti-TrustRank. TDR not only makes full use of both trust and distrust propagation, but also overcomes the disadvantages of both TrustRank and Anti-TrustRank. Experimental results on benchmark datasets show that TDR outperforms other semi-automatic anti-spam algorithms for both spam demotion and spam detection tasks under various criteria.
Mining text and social streams
Authors: Aggarwal Charu C.
Published: July 2014

The large amount of text data which are continuously produced over time in a variety of large scale applications such as social networks results in massive streams of data. Typically massive text streams are created by very large scale interactions of individuals, or by structured creations of particular kinds of content by dedicated organizations. An example in the latter category would be the massive text streams created by news-wire services. Such text streams provide unprecedented challenges to data mining algorithms from an efficiency perspective. In this paper, we review text stream mining algorithms for a wide variety of problems in data mining such as clustering, classification and topic modeling. A recent challenge arises in the context ofsocial streams, which are generated by large social networks such asTwitter. We also discuss a number of future challenges in this area of research.
Brain network analysis
Authors: Kong Xiangnan , Yu Philip S.
Published: July 2014

Following the recent advances in neuroimaging technology, the research on brain network analysis becomes an emerging area in data mining community. Brain network data pose many unique challenges for data mining research. For example, in brain networks, the nodes (i.e., the brain regions) and edges (i.e., relationships between brain regions) are usually not given, but should be derived from the neuroimaging data. The network structure can be very noisy and uncertain. Therefore, innovative methods are required for brain network analysis. Many research efforts have been devoted to this area. They have achieved great success in various applications, such as brain network extraction, graph mining, neuroimaging data analysis. In this paper, we review some recent data mining methods which are used in the literature for mining brain network data.
Predictive analysis of engine health for decision support
Authors: Mukherjee Shubhabrata , Varde Aparna S. , Javidi Giti , Sheyban Ehsan
Published: July 2014

Data mining, the discovery of knowledge from data, bridges several disciplines such as database management, artificial intelligence, statistics, visualization and the domain of the data, e.g., biology or engineering. Knowledge discovered by mining the data can be used for various purposes such as developing decision support systems and intelligent tutors. In this paper we present such a data mining problem in the mechanical engineering domain where knowledge discovery from the data is performed using statistical approaches, to conduct predictive analysis for decision support. More specifically, we focus on the engine health problem which consists of using existing data on the behavior of an engine in order to predict whether the engine is capable of functioning well (i.e., it is healthy) and to offer suggestions on preventive maintenance. The data we use for this predictive analysis consists of graphs that plot process parameters such as the vibration and temperature of the engine with respect to time. In this paper we define the problem in detail, propose a solution based on statistical inference techniques, summarize our experimental evaluation and discuss the applications of this work in various fields from a decision support angle.
The Mill
Authors: Godard Ivan
Published: July 2014

Real-world programs often thrash in the instruction cache, especially when SMT methods are used. The Mill™ split-stream encoding doubles the effective capacity of the instruction cache at no increase in perinstruction power usage or cache access latency, while also sharply increasing the potential maximal decode rate for instruction sets that use variable-length encoding.
Accelerating sequential Monte Carlo method for real-time air traffic management
Authors: Chau Thomas C.P. , Targett James S. , Wijeyasinghe Marlon , Luk Wayne , Cheung Peter Y.K. , Cope Benjamin , Eele Alison , Maciejowski Jan
Published: July 2014

This paper presents how field-programmable gate arrays (FPGAs) are used to accelerate the Sequential Monte Carlo method for air traffic management. A novel data structure is introduced for a particle stream that enables efficient evaluation of constraints and weights. A parallel implementation for this streaming data structure is designed, and an analytical model is provided for estimating the performance and resource usage of our implementation. We compare our design to implementations on CPU and GPU. We show 9.3 times speed up and 89 times improvement in energy efficiency over an Intel Core i7-950 CPU with 8 threads and demonstrate 1.3 times speed up and 13.5 times improvement in energy efficiency over an NVIDIA Tesla C2070 GPU with 448 cores. We also estimate the performance of FPGA in future scenario and show that FPGA is able to control 15 times and 2.8 times more aircraft than CPU and GPU in real-time respectively.
The Ultrasmall soft processor
Authors: Tanaka Yuichiroh , Sato Shimpei , Kise Kenji
Published: July 2014

A soft processor is a processor that is implemented using logic synthesis mainly targeting programmable logic device like FPGA and it becomes a common component for FPGA designs. The supersmall soft processor (small-core) developed at University of Toronto is an unique soft processor because its main concern is very low hardware cost while supporting 32-bit ISA.

With the same concept as small-core, we are developing the ultrasmall soft processor (UltraSmall) based on smallcore. The goal of this project is to implement the smallest 32-bit ISA soft processor while aiming to achieve high performance. We propose UltraSmall and describe its key ideas and implementations. The evaluation results indicate that the hardware cost of UltraSmall is smaller than smallcore in the latest FPGA while achieving 1.8x performance of small-core.
A run-time reconfigurable system for adaptive high performance efficient computing
Authors: Hong Chuan , Benkrid Khaled , Isa Nazrin , Iturbe Xabier
Published: July 2014

Field programmable hardware gives electronic systems the ability to be reconfigured at run time. This allows electronic systems to be more efficiently customized on demand and on-the-fly depending on user requirements and environmental changes. This paper presents a run-time reconfigurable system that allows computing tasks to adjust their sizes in response to current available resources, optimizing the overall performance by maximally exploiting all the resources on the chip. In particular, we present a novel run-time task assembler, which assembles tasks with desired parameters on-the-fly, together with an efficacious run-time task placer to rapidly configure tasks at optimum locations. The system is demonstrated with a dynamic programming-based pairwise sequence alignment application. Real hardware implementation result shows that our run-time reconfigurable system optimizes resource usage on the fly by ~ 3x, while matching the performance of carefully hand-crafted static solutions.
Statistical reform in information retrieval?
Authors: Sakai Tetsuya
Published: July 2014

IR revolves around evaluation. Therefore, IR researchers should employ sound evaluation practices. Nowadays many of us know that statistical significance testing is not enough, but not all of us know exactly what to do about it. This paper provides suggestions on how to report effect sizes and confidence intervals along with p-values, in the context of comparing IR systems using test collections. Hopefully, these practices will make IR papers more informative, and help researchers form more reliable conclusions that "add up." Finally, I pose a specific question for the IR community: should IR journal editors and SIGIR PC chairs require (rather than encourage) reporting of effect sizes and confidence intervals.
Report on the CIKM workshop on living labs for information retrieval evaluation
Authors: Balog Krisztian , Elsweiler David , Kanoulas Evangelos , Kelly Liadh , Smucker Mark D.
Published: July 2014

Evaluation is a central aspect of information retrieval (IR) research. In the past few years, a new evaluation methodology known as living labs has been proposed as a way for researchers to be able to perform in-situ evaluation. The first CIKM workshop on Living Labs for IR evaluation (LL'13) was held on 1st November 2013 in San Francisco, USA. The workshop consisted of an industrial keynote, four oral paper presentations, three demo presentations, and a discussion session. This report presents an overview of the scope and contents of the workshop and outlines the major outcomes.
Exploiting entities for query expansion
Authors: Brandão Wladmir Cardoso
Published: July 2014

A substantial fraction of web search queries contain references to entities, such as persons, organizations, and locations. This signi cant presence of named entities in queries provides an opportunity for web search engines to improve their understanding of the user's information need.

In this thesis, we investigate the entity-oriented query expansion process. Particularly, we propose two novel and effective query expansion approaches that exploit semantic sources of evidence to devise discriminative term features, and machine learning techniques to effectively combine these features in order to rank candidate expansion terms. As a result, not only do we select effective expansion terms, but we also weigh these terms according to their predicted effectiveness. In addition, since our query expansion approaches consider Wikipedia infoboxes as a source of candidate expansion terms, a frequent obstacle is that only about 20% of Wikipedia articles have an infobox. To overcome this problem we propose WAVE, a self-supervised approach to autonomously generate infoboxes for Wikipedia articles.

First, we propose UQEE, an unsupervised entity-oriented query expansion approach, which effectively selects expansion terms using taxonomic features devised by the semantic structure implicitly provided by infobox templates. We show that query expansion using infoboxes presents a better trade-off between retrieval performance and query latency. Moreover, we demonstrate that the automatically generated infoboxes provided by WAVE are as effective as manually generated infoboxes for query expansion. Lastly, we propose L2EE, a learning to rank approach for entity-oriented query expansion, which considers semantic evidence encoded in the content of Wikipedia article fields, and automatically labels training examples proportionally to their observed retrieval effectiveness.

Experiments on three TREC web test collections attest the effectiveness of L2EE, with significant gains compared to UQEE and state-of-the-art pseudo-relevance feedback and entity-oriented pseudo-relevance feedback approaches.