bluuebunny/crossref_metadata_2025 huggingface dataset:
Activation of AQP4, p66Shc and endoplasmic reticulum stress is involved in inflammation by carrageenan and is suppressed by argirein, a derivative of rhein
Authors: Cong Xiao-Dong , Wu You , Dai De-Zai , Ding Ming-Jian , Zhang Yun , Dai Yin
Published: March 2012

Objectives

We investigated the effect of argirein on acute inflammation edema and examined that aquaporin 4 (AQP4), p66Shc and activating transcription factor (ATF-6) might be involved in carrageenan-induced rat paw inflammation and be reversed by argirein, rhein and indometacin, but not l-arginine.

Methods

Inflammation was produced by carrageenan injected into rat paw and treated orally with argirein (100 mg/kg), rhein (100 mg/kg), l-arginine (100 mg/kg) or indometacin (5 mg/kg). Inflammatory oedema and biomarkers were examined.

Key findings

Swelling was reduced by argirein, rhein and indometacin; argirein was more effective than rhein at 1 h following medication. Activation of AQP4, p66Shc, ATF-6, NADPH oxidase subunits p22phox, gp91phox and matrix metalloproteinase 2 (P < 0.01) was significant and was suppressed by arginine, rhein and indometacin but not by l-arginine.

Conclusions

Activated AQP4, endoplasmic reticulum stress and p66Shc were actively implicated in the inflammation and these were suppressed by argirein, and its activity is favorable due to synergism in combination with l-arginine.
Personality and place
Authors: Gelade Garry A.
Published: March 2012

This paper examines the distribution of national personality dimensions in geographical space. The relationship between geographical location and aggregate personality in a wide range of nations is quantified using spatial autocorrelation, and it is found that the personalities of nations that are geographical neighbours are more similar than those that are far apart. The five factors of both the Revised NEO Personality Inventory (NEO‐PI‐R) and the Big Five Inventory (BFI), all show a significant degree of spatial organization. The personality factors most strongly associated with geographical location are NEO‐PI‐R extraversion and BFI conscientiousness; both vary with position around the globe about as much as the physical climate. These findings support previous research suggesting associations between aggregate personality and geography, and imply that the sources of variation in national personality are themselves geographically organized.
Existence of Solutions of Riccati Differential Equations
Authors: Kilicaslan Sinan , Banks Stephen P.
Published: March 2012

A necessary condition for the existence of the solution of the Riccati differential equation for both linear, time varying systems and nonlinear systems is introduced. First, a necessary condition for the existence of the solution of the Riccati differential equation for linear, time varying systems is proposed. Then, the sufficient conditions to satisfy the necessary condition are given. After that, the existence of the solution of the Riccati differential equation is generalized for nonlinear systems.
Residual Analysis of Autoregressive Models of Terrain Topology
Authors: Wagner Shannon , Ferris John B.
Published: March 2012

Terrain topology is the principal source of vertical excitation into the vehicle system and must be accurately represented in order to correctly predict the vehicle response. It is desirable to evaluate vehicle models over a wide range of terrain, but it is computationally impractical to simulate long distances of every terrain type. A method to parsimoniously characterize terrain topology is developed in this work so that terrain can be grouped into meaningful sets with similar topological characteristics. Specifically, measured terrain profiles are considered realizations of an underlying stochastic process; an autoregressive model and a residual process provide the mathematical framework to describe this process. A statistical test is developed to determine if the residual process is independent and identically distributed (IID) and, therefore, stationary. A reference joint probability distribution of the residuals is constructed based on the assumption that the data are realizations of an IID stochastic process. The distribution of the residuals is then compared to this reference distribution via the Kolmogorov–Smirnov “goodness of fit” test to determine whether the IID assumption is valid. If the residual process is IID, a single probability distribution can be used to generate residuals and synthetic terrain of any desired length. This modeling method and statistical test are applied to a set of U.S. highway profile data and show that the residual process can be assumed to be IID in virtually all of these cases of nondeformable terrain surfaces.
A Passive Fault Tolerant Flight Control for Maximum Allowable Vertical Tail Damaged Aircraft
Authors: Li Xiaobo , Liu Hugh H. T.
Published: March 2012

This paper investigates a passive fault tolerant control to aircraft that suffers from vertical tail damage. A novel notion of damage degree is introduced to parameterize the damaged flight dynamics model. It is applied to seek the maximum allowable damage degree (tolerance capacity) stabilizable by the proposed passive fault tolerant and backup control under a linearized model. The design algorithms are presented and illustrated through numerical simulations on a Boeing-747 100/200 model. Furthermore, the impact of potential control saturation is taken into account in the proposed design and a set of design parameters are tuned such that the maximum allowable damage degree is bounded, represented as the so-called critical damage degree.
Process Parameters Effect on Mechanical Properties and Fatigue Behavior of Friction Stir Weld AA6060 Joints
Authors: Longo M. , D’Urso G. , Giardini C. , Ceretti E.
Published: March 2012

Friction stir welding (FSW) is the most remarkable welding technology that has been invented and developed in the last decade. It is a solid-state welding process in which a rotating tool is driven into the material and translated along the interface of two or more plates. This technology has been successfully used to join materials that are considered difficult to be welded by fusion welding methods. FSW has potentially significant applications in many industrial fields such as aerospace, automotive, and naval industry. Anyway, FSW technology requires a meticulous understanding of the process and consequent mechanical properties of the welds in order to be used in the production of high performance components. The present work deals with an experimental campaign aimed at the evaluation of the mechanical properties of AA6060 T6 friction stir welded joints. The butt joints obtained using two different tool geometries (standard and threaded) were performed by varying the welding parameters, namely, tool rotating speed and feed rate. The standard tool was a very simple device fabricated using AISI 1040 steel, with a flat shoulder and a cylindrical pin. The threaded tool was a more complex device based on two main components: a tool holder, with a flat shoulder, and a threaded probe obtained using a commercial thread forming tap. The quality of the joints was evaluated in terms of both tensile strength (UTS) and fatigue behavior. The study of axial pulsing fatigue properties required the fabrication of a specific testing device able to avoid parasite bending moments. In order to estimate the more efficient and effective tool type, the welding forces (axial and longitudinal) were also measured.
Stability of Residual Stresses Created by Shot Peening in Monotonic Loading and at the Presence of Load Reversals—Experiments and Modeling
Authors: Dalaei K. , Persson C. , Karlsson B.
Published: March 2012

As a method for mechanical surface treatment, shot peening has been widely used to improve the fatigue strength of materials. However, the influence of residual stresses introduced by shot peening depends on their stability. The stability of residual stresses during fatigue may be studied in two stages: the first cycle and successive cyclic loading. In this study the stability and development of the residual stresses during the first cycle of strain controlled fatigue of normalized steel was investigated. The influence of total strain amplitude and the loading direction was studied. The residual stresses were obtained using the x-ray diffraction technique. It was shown that the stability and relaxation of the residual stresses depend both on the amount and the direction of the loading stresses. Finite element modeling (FEM) was used to rationalize the experimental data. Very good agreement between the experimental and FEM results were observed.
Analysis of Carbon Nanotubes and Graphene Nanoribbons With Folded Racket Shapes
Authors: Plaut R. H. , Borum A. D. , Dillard D. A.
Published: March 2012

Folding of carbon nanotubes and graphene nanoribbons into a shape that looks like a tennis racket is considered. An elastic continuum model is utilized in two types of analysis. The first is called an “adhesion model,” in which the adjacent sides of the racket handle are assumed to be straight and bonded together with constant or no separation. The nanotube or nanoribbon is represented as an elastica. This model has been treated in the literature, but new analytical results are derived here, involving the geometry, work of adhesion, and bending and adhesion energies. Expressions are determined for (i) the length for which the total energy is the same as for the straight unstrained equilibrium configuration and (ii) for the minimum length for existence of a stable racket equilibrium shape. The second type of analysis uses the Lennard-Jones potential to model the attractive (van der Waals) and repulsive forces between the two sides of the racket. A nanoribbon is investigated, and the derivative of the interatomic potential is integrated along the length and across the width. Numerical solutions of the integro-differential equations are obtained with a new technique utilizing the finite difference method and minimization of the squares of the resulting algebraic equations. The results are presented for two cases with different flexural rigidities. The separation between the two sides of the handle decreases in the direction of the racket head (loop), and the handle experiences internal compression under the external attractive and repulsive forces. For the adhesion model, the dimensions of the head are proportional to the square root of the flexural rigidity, and this relationship is approximately satisfied in the numerical results based on the Lennard-Jones model.
The Contribution of History in Plastic Behavior of Metals in Machining
Authors: Vaziri M. R. , Mashayekhi M. , Salimi M.
Published: March 2012

Mechanical and thermal properties significantly affect many aspects of machining, such as chip formation, cutting forces, cutting temperatures, and surface integrity of machined products. One of the most important mechanical properties is the material flow stress, which is governed by the field variables including the strain, strain rate, and temperature. Due to the presence of high values of these variables in machining, it is important to evaluate the performance of different material models, typically developed at much lower strains, strain rates, and temperatures. The other issue is to identify the effect of the history of these variables that material microvolume experiences while moving through the shear zones and include them in the model. It is demonstrated that such material models may be suitable choices to describe the material flow in simulation of machining, which leads to an extrapolation from the mathematical form of these models. In addition, this paper discuses the importance of history dependency in flow stress and compares the performance of three commonly employed material constitutive models including the nonhistory-dependent Johnson–Cook (J–C) model, the empirical Oxley model, and the history-dependent Maekawa model. It is demonstrated that among the metals with different crystal structures, the flow stress of face-centered cubic (FCC) metals is highly affected by the strain path and is very little sensitive to temperature and strain-rate changes. In addition, the magnitudes of these effects are discussed.
Model of Droplet Impingement Based on Least-Squares Solution of Proper Orthogonal Decomposition Basis Matrices
Authors: Hanchak M. S. , Byrd L. W. , Briones A. M. , Ervin J. S. , Putnam S. A.
Published: March 2012

A reduced order model of the surface profiles of droplets impinging on a flat surface is presented based on axisymmetric, transient computational fluid dynamics (CFD). The free surfaces resulting from the volume-of-fluid simulations were interpolated in polar coordinates and arranged as rectangular matrices (time versus space). Proper orthogonal decomposition was then used to expand the data into sets of temporal and spatial basis vectors, which were truncated beyond diminishing singular values. The reduced model is a general linear combination of constant matrices and dimensionless parameters that, when combined, recreate the temporal and spatial basis vectors for each case. The constant matrices were determined with a least-squares solution to the overdetermined linear combinations. To predict a new case, the initial Reynolds, Weber, and Ohnesorge numbers were combined with the calculated constant matrices to determine the new basis vectors, which were used to create the new free surface profile. A new case predicted by the model was validated using a CFD simulation. The single maximum error between the CFD profile and the general linear model was approximately 9% of the initial droplet diameter. The root-mean-squared error for the entire droplet motion was approximately 2% of the initial droplet diameter.
GBP5 Promotes NLRP3 Inflammasome Assembly and Immunity in Mammals
Authors: Shenoy Avinash R. , Wellington David A. , Kumar Pradeep , Kassa Hilina , Booth Carmen J. , Cresswell Peter , MacMicking John D.
Published: March 2012

Generating Inflammasomes

Inflammasomes are large, multiprotein complexes that assemble in response to infection that are also involved in the pathogenesis of a variety of other diseases, including type 2 diabetes and atherosclerosis. The assembly of the inflammasome triggers an inflammatory cascade that results in the activation of caspase-1 and production of the cytokines interleukin-1 and -18. Very little, however, is known about the specific signals that trigger inflammasome assembly.

Shenoy
et al.

(p. 481, published online 29 March; see the Perspective by

Caffrey and Fitzgerald

) now show that guanylate binding protein 5 (GBP5) promotes the assembly of the NLRP3-containing inflammasome in response to certain activation signals, such as pathogenic bacteria and adenosine triphosphate, but not others, like crystalline stimuli. Mice deficient in GBP5 exhibited impaired caspase-1 activation and production of cytokines. NLRP3 inflammasome–dependent responses to pathogenic bacteria and inflammatory stimuli were also impaired in mice lacking GBP5.
A Dynamic Network Model of mTOR Signaling Reveals TSC-Independent mTORC2 Regulation
Authors: Dalle Pezze Piero , Sonntag Annika G. , Thien Antje , Prentzell Mirja T. , Gödel Markus , Fischer Sven , Neumann-Haefelin Elke , Huber Tobias B. , Baumeister Ralf , Shanley Daryl P. , Thedieck Kathrin
Published: March 2012

Modeling and testing network structures reveal a distinct mechanism of mTORC2 activation by insulin.
Chronic Activation of mTOR Complex 1 Is Sufficient to Cause Hepatocellular Carcinoma in Mice
Authors: Menon Suchithra , Yecies Jessica L. , Zhang Hui H. , Howell Jessica J. , Nicholatos Justin , Harputlugil Eylul , Bronson Roderick T. , Kwiatkowski David J. , Manning Brendan D.
Published: March 2012

Aberrant activation of the mammalian target of rapamycin complex 1 disrupts tissue homeostasis, leading to carcinogenesis.
Donuts Dissociate
Authors: Hines Pamela J.
Published: March 2012

A tryptophan pyramid allows a dimeric protein to perceive ultraviolet light without an additional chromophore.
Toxin Receptors Unite
Authors: Gough Nancy R.
Published: March 2012

Neurexin and CL1 interact and can mediate cellular adhesion.
Native Valve Endocarditis Caused by Corynebacterium striatum with Heterogeneous High-Level Daptomycin Resistance: Collateral Damage from Daptomycin Therapy?
Authors: Tran Truc T. , Jaijakul Siraya , Lewis Cole T. , Diaz Lorena , Panesso Diana , Kaplan Heidi B. , Murray Barbara E. , Wanger Audrey , Arias Cesar A.
Published: March 2012

We describe a patient who developed
Corynebacterium striatum
native valve endocarditis after receiving two 6-week courses of daptomycin for the treatment of methicillin-resistant
Staphylococcus aureus
bacteremia and osteomyelitis. The organism exhibited
in vitro
heteroresistance to daptomycin, with two subpopulations showing daptomycin susceptibility (MIC of ≤0.094 μg/ml) and high-level resistance to daptomycin (MIC of ≥256 μg/ml). The selection of daptomycin-resistant Gram-positive skin flora with the potential of causing invasive disease may be a concern during prolonged courses of daptomycin.
Membrane-Active Action Mode of Polybia-CP, a Novel Antimicrobial Peptide Isolated from the Venom of Polybia paulista
Authors: Wang Kairong , Yan Jiexi , Chen Ru , Dang Wen , Zhang Bangzhi , Zhang Wei , Song Jingjing , Wang Rui
Published: March 2012

The extensive use of antibiotics in medicine, the food industry, and agriculture has resulted in the frequent emergence of multidrug-resistant bacteria, which creates an urgent need for new antibiotics. It is now widely recognized that antimicrobial peptides (AMPs) could play a promising role in fighting multidrug-resistant bacteria. Antimicrobial peptide polybia-CP was purified from the venom of the social wasp
Polybia paulista
. In this study, we synthesized polybia-CP and studied its action mode of antibacterial activity. Our results revealed that polybia-CP has potent antibacterial activity against both Gram-positive and Gram-negative bacteria. The results from both the real bacterial membrane and the
in vitro
model membrane showed that polybia-CP is membrane active and that its action target is the membrane of bacteria. It is difficult for bacteria to develop resistance to polybia-CP, which may thus offer a new strategy for defending against resistant bacteria in medicine and the food and farming industries.
Kinetic Analysis of Enterococcus faecium
l
,
d
-Transpeptidase Inactivation by Carbapenems
Authors: Dubée Vincent , Arthur Michel , Fief Hélène , Triboulet Sébastien , Mainardi Jean-Luc , Gutmann Laurent , Sollogoub Matthieu , Rice Louis B. , Ethève-Quelquejeu Mélanie , Hugonnet Jean-Emmanuel
Published: March 2012

Bypass of classical penicillin-binding proteins by the
l
,
d
-transpeptidase of
Enterococcus faecium
(Ldt
fm
) leads to high-level ampicillin resistance in
E. faecium
mutants, whereas carbapenems remain the lone highly active β-lactams. Kinetics of Ldt
fm
inactivation was determined for four commercial carbapenems and a derivative obtained by introducing a minimal ethyl group at position 2. We show that the bulky side chains of commercial carbapenems have both positive and negative effects in preventing hydrolysis of the acyl enzyme and impairing drug binding.
FlaA Proteins in Leptospira interrogans Are Essential for Motility and Virulence but Are Not Required for Formation of the Flagellum Sheath
Authors: Lambert Ambroise , Picardeau Mathieu , Haake David A. , Sermswan Rasana W. , Srikram Amporn , Adler Ben , Murray Gerald A.
Published: March 2012

Spirochetes have periplasmic flagella composed of a core surrounded by a sheath. The pathogen
Leptospira interrogans
has four
flaB
(proposed core subunit) and two
flaA
(proposed sheath subunit) genes. The
flaA
genes are organized in a locus with
flaA2
immediately upstream of
flaA1
. In this study,
flaA1
and
flaA2
mutants were constructed by transposon mutagenesis. Both mutants still produced periplasmic flagella. The
flaA1
mutant did not produce FlaA1 but continued to produce FlaA2 and retained normal morphology and virulence in a hamster model of infection but had reduced motility. The
flaA2
mutant did not produce either the FlaA1 or the FlaA2 protein. Cells of the
flaA2
mutant lacked the distinctive hook-shaped ends associated with
L. interrogans
and lacked translational motility in liquid and semisolid media. These observations were confirmed with a second, independent
flaA2
mutant. The
flaA2
mutant failed to cause disease in animal models of acute infection. Despite lacking FlaA proteins, the flagella of the
flaA2
mutant were of the same thickness as wild-type flagella, as measured by electron microscopy, and exhibited a normal flagellum sheath, indicating that FlaA proteins are not essential for the synthesis of the flagellum sheath, as observed for other spirochetes. This study shows that FlaA subunits contribute to leptospiral translational motility, cellular shape, and virulence.
Myeloid-Derived Suppressor Cells Evolve during Sepsis and Can Enhance or Attenuate the Systemic Inflammatory Response
Authors: Brudecki Laura , Ferguson Donald A. , McCall Charles E. , El Gazzar Mohamed
Published: March 2012

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous Gr1+CD11b+population of immature cells containing granulocytic and monocytic progenitors, which expand under nearly all inflammatory conditions and are potent repressors of T-cell responses. Studies of MDSCs during inflammatory responses, including sepsis, suggest they can protect or injure. Here, we investigated MDSCs during early and late sepsis. To do this, we used our published murine model of cecal ligation and puncture (CLP)-induced polymicrobial sepsis, which transitions from an early proinflammatory phase to a late anti-inflammatory and immunosuppressive phase. We confirmed that Gr1+CD11b+MDSCs gradually increase after CLP, reaching ∼88% of the bone marrow myeloid series in late sepsis. Adoptive transfer of early (day 3) MDSCs from septic mice into naive mice after CLP increased proinflammatory cytokine production, decreased peritoneal bacterial growth, and increased early mortality. Conversely, transfer of late (day 12) MDSCs from septic mice had the opposite effects. Early and late MDSCs studiedex vivoalso differed in their inflammatory phenotypes. Early MDSCs expressed nitric oxide and proinflammatory cytokines, whereas late MDSCs expressed arginase activity and anti-inflammatory interleukin 10 (IL-10) and transforming growth factor β (TGF-β). Late MDSCs had more immature CD31+myeloid progenitors and, when treatedex vivowith granulocyte-macrophage colony-stimulating factor (GM-CSF), generated fewer macrophages and dendritic cells than early MDSCs. We conclude that as the sepsis inflammatory process progresses, the heterogeneous MDSCs shift to a more immature state and from being proinflammatory to anti-inflammatory.
Why do so few patients with heart failure participate in cardiac rehabilitation? A cross-sectional survey from England, Wales and Northern Ireland
Authors: Dalal Hasnain M , Wingham Jennifer , Palmer Joanne , Taylor Rod , Petre Corinna , Lewin Robert
Published: March 2012

Objectives

To determine why so few patients with chronic heart failure in England, Wales and Northern Ireland take part in cardiac rehabilitation.

Design

Two-stage, postal questionnaire-based national survey.

Participants and setting

Stage 1: 277 cardiac rehabilitation centres that provided phase 3 cardiac rehabilitation in England, Wales and Northern Ireland registered on the National Audit of Cardiac Rehabilitation register. Stage 2: 35 centres that indicated in stage 1 that they provide a separate cardiac rehabilitation programme for patients with heart failure.

Results

Full data were available for 224/277 (81%) cardiac rehabilitation centres. Only 90/224 (40%) routinely offered phase 3 cardiac rehabilitation to patients with heart failure. Of these 90 centres that offered rehabilitation, 43% did so only when heart failure was secondary to myocardial infarction or revascularisation. Less than half (39%) had a specific rehabilitation programme for heart failure. Of those 134 centres not providing for patients with heart failure, 84% considered a lack of resources and 55% exclusion from commissioning contracts as the reason for not recruiting patients with heart failure. Overall, only 35/224 (16%) centres provided a separate rehabilitation programme for people with heart failure.

Conclusions

Patients with heart failure as a primary diagnosis are excluded from most cardiac rehabilitation programmes in England, Wales and Northern Ireland. A lack of resources and direct exclusion from local commissioning agreements are the main barriers for not offering rehabilitation to patients with heart failure.
A170P mutation inSHOXgene in a patient not presenting with Madelung deformity: Figure 1
Authors: Álvarez-Mora María Isabel , Madrigal Irene , Rodriguez-Revenga Laia , Mur Antonio , Calvo Dolors , Pascual i Bardají Josep , Milà Montserrat
Published: March 2012

Idiopathic short stature is a multifactorial disease caused by defects in several genes. Among them, short stature homeobox-containing gene (SHOX) mutations have an incidence of 2%–15% within the idiopathic short population. The authors report a patient with moderate intellectual disability, short stature and no other radiological traits referred for subtelomeric screening. MLPA and sequencing results showed a heterozygous mutation inSHOXgene (A170P). This mutation has been described to fully cosegregate with Madelung deformity in patients affected with Léri–Weill dyschondrosteosis and Langer mesomelic dysplasia. The authors report the first case of idiopathic short stature due to the A170P mutation in a patient without any radiological trait. The A170P mutation is the most prevalent mutation in the Spanish gypsy population affected with short stature disorders. The authors strongly recommendSHOXscreening for deletions, duplications and point mutations in patients affected with short stature although they do not present any radiological traits.
Efficacy of ethinylestradiol 20 µg/drospirenone 3 mg in a flexible extended regimen in women with moderate-to-severe primary dysmenorrhoea: an open-label, multicentre, randomised, controlled study
Authors: Strowitzki Thomas , Kirsch Bodo , Elliesen Jörg
Published: March 2012

Objectives

The aim of this Phase III, multicentre, open-label, randomised study was to compare the efficacy and safety of ethinylestradiol (EE)/drospirenone (DRSP) in a new flexible extended regimen that allowed the management of intracyclic (breakthrough) bleeding (MIB) with that of EE/DRSP in a conventional 28-day regimen in women with moderate-to-severe primary dysmenorrhoea.

Methods

Women (aged 18–40 years) with moderate-to-severe primary dysmenorrhoea-related pain received a flexible extended regimen with MIB (flexibleMIB; minimum 24, maximum 120 days of continuous tablet intake for a flexible number of cycles to reach a treatment duration of at least 140 days with 4-day breaks between cycles) or a conventional 28-day regimen (24 active and four placebo tablets for five cycles) of EE/DRSP. The primary outcome was the number of days with dysmenorrhoeic pain over 140 days. Secondary outcomes included other dysmenorrhoea-related pain outcomes, bleeding profile, satisfaction and safety.

Results

Overall, 223 patients received study medication. There were significantly fewer days with dysmenorrhoeic pain with the flexibleMIBregimen than the conventional regimen (difference −4.2 days, 95% CI −6.5 to −2.0;p=0.0003), as well as considerably fewer days with at least moderate dysmenorrhoeic pain (difference −2.5 days, 95% CI −3.7 to −1.3), dysmenorrhoeic pain that interfered with daily activities (difference −2.2 days, 95% CI −4.2 to −0.1) and pelvic pain (difference −3.4 days, 95% CI −5.9 to −0.9). Adverse events were similar with both regimens.

Conclusions

Compared with the conventional regimen, the flexible extended regimen of EE/DRSP with MIB was associated with a significantly greater reduction in days with dysmenorrhoeic pain in women with moderate-to-severe primary dysmenorrhoea. The flexibleMIBregimen was also associated with greater improvements in dysmenorrhea according to the Clinical Global Impression rating scale and was generally well tolerated.
RESEARCH ON TRUST PREDICTION MODEL FOR SELECTING WEB SERVICES BASED ON MULTIPLE DECISION FACTORS
Authors: LI XIAOYONG , ZHOU FENG , YANG XUDONG
Published: March 2012

With the widespread application of web services, trust-based service selection has become a significant requirement from a requester's point of view, and trust prediction mechanism has become a determining factor for any given service's success. But the dynamic nature of trust creates the biggest challenge in measuring a trust value and make trust predictions. In this paper, a new trust prediction model is proposed based on multiple decision factors. Firstly, the proposed model integrates multiple complementary decision factors to reflect complexity and uncertainty of trust relationship. In addition to including traditional experience-based trust factor and feedback-based trust factor, this model innovatively integrates QoS-based trust factor into global trust evaluation, which makes the model have a better rationality and a higher practicability than the existing approaches. Meanwhile, the proposed model applies the theory of OWA (Ordered Weighted Averaging) operator to assign the classification weights to these decision factors, which makes the model exhibit a strong adaptability in handling various dynamic behaviors of service providers. Simulation results show that, compared to the existing approaches, the proposed model has remarkable enhancements in the accuracy of trust prediction.
AUTOMATIC ONTOLOGY CONSTRUCTION IN FICTION-BASED DOMAIN
Authors: GOH HUI-NGO , KIU CHING-CHIEH , SOON LAY-KI , RANAIVO-MALANÇON BALI
Published: March 2012

The field of ontology has received attention lately due to the increasing needs in conceptualizing the domain knowledge for resolving various jobs' demand. Numerous new techniques, tools and applications have then been developed for their suitability in managing knowledge. However, most works carried out focused on non-fiction domain and categorizing the concepts into component or cluster. Hence, the originality of the content flow is not preserved. This paper presents an automated ontology construction in fiction domain. The significance of the study lies in (1) designing a simple and easy algorithmic framework for automated ontology construction while preserving the originality of the content flow in an ontology, (2) identification of suitable threshold value in extracting true terms, and (3) process an unstructured fiction-based domain text into meaningful structure automatically.
CAPTURING INTERFACE PROTOCOLS TO SUPPORT COMPREHENSION AND EVALUATION OF C++ LIBRARIES
Authors: MALLOY BRIAN A. , LLOYD ERROL L. , HALLSTROM JASON O. , DUFFY EDWARD B.
Published: March 2012

Developing and maintaining reliable object-oriented software requires a precise understanding of how individual classes must be used. Unfortunately, for many systems, especially those that are large, the available documentation is inadequate. Developers are left with incomplete information concerning the allowable set of call sequences that each class can accommodate. Techniques for reverse engineering this information and presenting it to developers in an intellectually scalable manner are critical.

In this paper, we present four contributions to address this challenge. First, we describe a runtime trace collection system for large C++ applications. Second, we present a methodology for reverse engineering interface protocols from collected trace data. Third, we present a scalable, tunable algorithm for generating compact specifications of these protocols. Finally, we present a detailed case study involving the Mozilla Necko library. We consider popular applications in common use constructed using this library. The results are promising both in terms of the performance of the approach and the utility of the identified protocols.
PROCESSING CONTINUOUS QUERIES ON SENSOR-BASED MULTIMEDIA DATA STREAMS BY MULTIMEDIA DEPENDENCY ANALYSIS AND ONTOLOGICAL FILTERING
Authors: CHANG SHI-KUO , COLACE FRANCESCO , ZHAO LEI , SUN YAO
Published: March 2012

We present a mathematical model of multimedia data streams and a framework for multimedia functional dependency analysis. The dual objectives are to effectively design multimedia data streams schema and to efficiently process continuous queries on sensor-based multimedia data streams. To further improve query processing, we introduce the concept of ontological filtering. A software tool to add multimedia functional dependencies to ontology is developed. Based upon multimedia functional dependency analysis and ontological filtering, query processing algorithms, illustrative examples and experimental results for sensor-based multimedia data streams continuous querying are presented to demonstrate the practical applications of our approach.
NEUTRON SKIN THICKNESS IN NEUTRON-RICH NUCLEI: BULK AND SURFACE CONTRIBUTIONS AND SHELL EFFECTS
Authors: VIÑAS X. , WARDA M. , CENTELLES M. , ROCA-MAZA X.
Published: March 2012

We analyze theoretically the neutron skin thickness in nuclei and its correlation with the symmetry energy by using semiclassical and mean field approaches together with nuclear effective interactions. Semiclassical approaches reveal that the neutron skin thickness in nuclei is formed by a combination of bulk and surface contributions. To investigate the neutron skin thickness predicted by mean field models, we fit the corresponding densities by two-parameter Fermi distributions. Using these parametrized densities, we study the neutron skin thickness as well as its bulk and surface contributions in 208 Pb and in Zr isotopes, where the influence of shell effects along the isotopic chain is discussed.
ON THE STABILITY OF THE BEST REPLY MAP FOR NONCOOPERATIVE DIFFERENTIAL GAMES
Authors: BRESSAN ALBERTO , WANG ZIPENG
Published: March 2012

Consider a differential game for two players in infinite time horizon, with exponentially discounted costs. A pair of feedback controls [Formula: see text] is Nash equilibrium solution if [Formula: see text] is the best strategy for Player 1 in reply to [Formula: see text], and [Formula: see text] is the best strategy for Player 2, in reply to [Formula: see text]. The aim of the present note is to investigate the stability of the best reply map: [Formula: see text]. For linear-quadratic games, we derive a condition which yields asymptotic stability, within the class of feedbacks which are affine functions of the state x ∈ ℝn. An example shows that stability is lost, as soon as nonlinear perturbations are considered.
NEW MATERIALS FOR INNOVATIVE ENERGY SYSTEMS PRODUCED BY COLD PLASMA TECHNIQUE
Authors: TYCZKOWSKI JACEK
Published: March 2012

The cold plasma technique, developed especially in recent years, opens the door to new materials with unique properties. This is related both to the plasma deposited thin films, which constitute integrally new materials, and to the plasma surface treatments, which drastically change the surface properties of conventional materials. Looking for novel solutions for innovative energy systems, it has been found that the both types of plasma activity are very useful for this purpose. The objective of this paper is to demonstrate the possibilities of the cold plasma technique for preparation of new materials for energy systems. A few examples of recent studies on such materials are presented. A special attention is focused on plasma deposited optoelectronically active thin films for solar cells, nanocatalytic thin films for fuel cells and plasma treated carbon electrodes for supercapacitors. These examples confirm the important role of the cold plasma technique in the development of modern and advanced energy systems.
Efficient Mining of Gap-Constrained Subsequences and Its Various Applications
Authors: Li Chun , Yang Qingyan , Wang Jianyong , Li Ming
Published: March 2012

Mining frequent subsequence patterns is a typical data-mining problem and various efficient sequential pattern mining algorithms have been proposed. In many application domains (e.g., biology), the frequent subsequences confined by the predefined gap requirements are more meaningful than the general sequential patterns. In this article, we propose two algorithms, Gap-BIDE for mining closed gap-constrained subsequences from a set of input sequences, and Gap-Connect for mining repetitive gap-constrained subsequences from a single input sequence. Inspired by some state-of-the-art closed or constrained sequential pattern mining algorithms, the Gap-BIDE algorithm adopts an efficient approach to finding the complete set of closed sequential patterns with gap constraints, while the Gap-Connect algorithm efficiently mines an approximate set of long patterns by connecting short patterns. We also present several methods for feature selection from the set of gap-constrained patterns for the purpose of classification and clustering. Our extensive performance study shows that our approaches are very efficient in mining frequent subsequences with gap constraints, and the gap-constrained pattern based classification/clustering approaches can achieve high-quality results.
Isolation-Based Anomaly Detection
Authors: Liu Fei Tony , Ting Kai Ming , Zhou Zhi-Hua
Published: March 2012

Anomalies are data points that are few and different. As a result of these properties, we show that, anomalies are susceptible to a mechanism called
isolation
. This article proposes a method called Isolation Forest (
i
Forest), which detects anomalies purely based on the concept of isolation without employing any distance or density measure---fundamentally different from all existing methods.

As a result,
i
Forest is able to exploit subsampling (i) to achieve a low linear time-complexity and a small memory-requirement and (ii) to deal with the effects of swamping and masking effectively. Our empirical evaluation shows that
i
Forest outperforms ORCA, one-class SVM, LOF and Random Forests in terms of AUC, processing time, and it is robust against masking and swamping effects.
i
Forest also works well in high dimensional problems containing a large number of irrelevant attributes, and when anomalies are not available in training sample.
Information Leaks in Structured Peer-to-Peer Anonymous Communication Systems
Authors: Mittal Prateek , Borisov Nikita
Published: March 2012

We analyze information leaks in the lookup mechanisms of structured peer-to-peer (P2P) anonymous communication systems and how these leaks can be used to compromise anonymity. We show that the techniques used to combat active attacks on the lookup mechanism dramatically increase information leaks and the efficacy of passive attacks, resulting in a tradeoff between robustness to active and passive attacks.

We study this tradeoff in two P2P anonymous systems: Salsa and AP3. In both cases, we find that, by combining both passive and active attacks, anonymity can be compromised much more effectively than previously thought, rendering these systems insecure for most proposed uses. Our results hold even if security parameters are changed or other improvements to the systems are considered. Our study, therefore, shows the importance of considering these attacks in P2P anonymous communication.
The effects of common random numbers on stochastic kriging metamodels
Authors: Chen Xi , Ankenman Bruce E. , Nelson Barry L.
Published: March 2012

Ankenman et al. introduced stochastic kriging as a metamodeling tool for representing stochastic simulation response surfaces, and employed a very simple example to suggest that the use of Common Random Numbers (CRN) degrades the capability of stochastic kriging to predict the true response surface. In this article we undertake an in-depth analysis of the interaction between CRN and stochastic kriging by analyzing a richer collection of models; in particular, we consider stochastic kriging models with a linear trend term. We also perform an empirical study of the effect of CRN on stochastic kriging. We also consider the effect of CRN on metamodel parameter estimation and response-surface gradient estimation, as well as response-surface prediction. In brief, we confirm that CRN is detrimental to prediction, but show that it leads to better estimation of slope parameters and superior gradient estimation compared to independent simulation.
Fast synthesis of persistent fractional Brownian motion
Authors: Inácio Pedro R. M. , Freire Mário M. , Pereira Manuela , Monteiro Paulo P.
Published: March 2012

Due to the relevance of self-similarity analysis in several research areas, there is an increased interest in methods to generate realizations of self-similar processes, namely in the ones capable of simulating long-range dependence. This article describes a new algorithm to approximate persistent fractional Brownian motions with a predefined Hurst parameter. The algorithm presents a computational complexity ofO(n) and generates sequences withn(n∈ N) values with a small multiple of log2(n) variables. Because it operates in a sequential manner, the algorithm is suitable for simulations demanding real-time operation. A network traffic simulator is presented as one of its possible applications.
Learning to Program with Personal Robots
Authors: McGill Monica M.
Published: March 2012

One of the goals of using robots in introductory programming courses is to increase motivation among learners. There have been several types of robots that have been used extensively in the classroom to teach a variety of computer science concepts. A more recently introduced robot designed to teach programming to novice students is the Institute for Personal Robots in Education (IPRE) robot. The author chose to use this robot and study its motivational effects on non-computer science students in a CS0 course. The purpose of this study was to determine whether using the IPRE robots motivates students to learn programming in a CS0 course. After considering various motivational theories and instruments designed to measure motivation, the author used Keller’s Instructional Materials Motivation Survey to measure four components of motivation: attention, relevance, confidence, and satisfaction. Additional items were added to the survey, including a set of open-ended questions. The results of this study indicate that the use of these robots had a positive influence on participants’ attitudes towards learning to program in a CS0 course, but little or no effect on relevance, confidence, or satisfaction. Results also indicate that although gender and students interests may affect individual components of motivation, gender, technical self-perception, and interest in software development have no bearing on the overall motivational levels of students.
Approximating Linear Threshold Predicates
Authors: Cheraghchi Mahdi , Håstad Johan , Isaksson Marcus , Svensson Ola
Published: March 2012

We study constraint satisfaction problems on the domain {−1, 1}, where the given constraints are homogeneous linear threshold predicates, that is, predicates of the form sgn(
w
1
x
1
+ ⋯ +
w
n
x
n
) for some positive integer weights
w
1
, ...,
w
n
. Despite their simplicity, current techniques fall short of providing a classification of these predicates in terms of approximability. In fact, it is not easy to guess whether there exists a homogeneous linear threshold predicate that is approximation resistant or not.

The focus of this article is to identify and study the approximation curve of a class of threshold predicates that allow for nontrivial approximation. Arguably the simplest such predicate is the majority predicate sgn(
x
1
+ ⋯ +
x
n
), for which we obtain an almost complete understanding of the asymptotic approximation curve, assuming the Unique Games Conjecture. Our techniques extend to a more general class of “majority-like” predicates and we obtain parallel results for them. In order to classify these predicates, we introduce the notion of
Chow-robustness
that might be of independent interest.
Is accessibility conformance an elusive property? A study of validity and reliability of WCAG 2.0
Authors: Brajnik Giorgio , Yesilada Yeliz , Harper Simon
Published: March 2012

The Web Content Accessibility Guidelines (WCAG) 2.0 separate testing into both “Machine” and “Human” audits; and further classify “Human Testability” into “Reliably Human Testable” and “Not Reliably Testable”; it is human testability that is the focus of this paper. We wanted to investigate the likelihood that “at least 80% of knowledgeable human evaluators would agree on the conclusion” of an accessibility audit, and therefore understand the percentage of success criteria that could be described as reliably human testable, and those that could not. In this case, we recruited twenty-five experienced evaluators to audit four pages for WCAG 2.0 conformance. These pages were chosen to differ in layout, complexity, and accessibility support, thereby creating a small but variable sample.

We found that an 80% agreement between experienced evaluators almost never occurred and that the average agreement was at the 70--75% mark, while the error rate was around 29%. Further, trained—but novice—evaluators performing the same audits exhibited the same agreement to that of our more experienced ones, but a reduction on validity of 6--13% ; the validity that an untrained user would attain can only be a conjecture. Expertise appears to improve (by 19%) the ability to avoid false positives. Finally, pooling the results of two independent experienced evaluators would be the best option, capturing
at most
76% of the true problems and producing
only
24% of false positives. Any other
independent
combination of audits would achieve worse results.

This means that an 80% target for agreement, when audits are conducted without communication between evaluators, is not attainable, even with experienced evaluators, when working on pages similar to the ones used in this experiment; that the error rate even for experienced evaluators is relatively high and further, that untrained accessibility auditors be they developers or quality testers from other domains, would do much worse than this.
Polymorphic type inference for scripting languages with object extensions
Authors: Zhao Tian
Published: March 2012

This paper presents a polymorphic type inference algorithm for a small subset of JavaScript. The goal is to prevent accessing undefined members of objects. We define a type system that allows explicit extension of objects through add operation and implicit extension through method calls. The type system also permits strong updates and unrestricted extensions to new objects. The type inference algorithm is modular so that each function definition is only analyzed once and larger programs can be checked incrementally.
Bounded-latency regional garbage collection
Authors: Klock Felix S. , Clinger William D.
Published: March 2012

Regional garbage collection is scalable, with theoretical worst-case bounds for gc latency, MMU, and throughput that are independent of mutator behavior and the volume of reachable storage. Regional collection improves upon the worst-case pause times and MMU seen in most other general-purpose collectors, including garbage-first and concurrent mark/sweep collectors.
Managing Technical Debt
Authors: Allman Eric
Published: March 2012

In 1992, Ward Cunningham published a report at OOPSLA (Object-oriented Programming, Systems, Languages, and Applications) in which he proposed the concept of technical debt. He defines it in terms of immature code: "Shipping first-time code is like going into debt." Technical debt isn’t limited to first-time code, however. There are many ways and reasons (not all bad) to take on technical debt.