bluuebunny/crossref_metadata_2025 huggingface dataset:
Expanding the Regulatory Network Governed by the Extracytoplasmic Function Sigma Factor σHin Corynebacterium glutamicum
Authors: Toyoda Koichi , Teramoto Haruhiko , Yukawa Hideaki , Inui Masayuki
Published: November 2014

The extracytoplasmic function sigma factor σHis responsible for the heat and oxidative stress response inCorynebacterium glutamicum. Due to the hierarchical nature of the regulatory network, previous transcriptome analyses have not been able to discriminate between direct and indirect targets of σH. Here, we determined the direct genome-wide targets of σHusing chromatin immunoprecipitation with microarray technology (ChIP-chip) for analysis of a deletion mutant ofrshA, encoding an anti-σ factor of σH. Seventy-five σH-dependent promoters, including 39 new ones, were identified. σH-dependent, heat-inducible transcripts for several of the new targets, includingilvDencoding a labile Fe-S cluster enzyme, dihydroxy-acid dehydratase, were detected, and their 5′ ends were mapped to the σH-dependent promoters identified. Interestingly, functional internal σH-dependent promoters were found in operon-like gene clusters involved in the pentose phosphate pathway, riboflavin biosynthesis, and Zn uptake. Accordingly, deletion ofrshAresulted in hyperproduction of riboflavin and affected expression of Zn-responsive genes, possibly through intracellular Zn overload, indicating new physiological roles of σH. Furthermore,sigAencoding the primary σ factor was identified as a new target of σH. Reporter assays demonstrated that the σH-dependent promoter upstream ofsigAwas highly heat inducible but much weaker than the known σA-dependent one. Our ChIP-chip analysis also detected the σH-dependent promoters upstream ofrshAwithin thesigH-rshAoperon and ofsigBencoding a group 2 σ factor, supporting the previous findings of their σH-dependent expression. Taken together, these results reveal an additional layer of the sigma factor regulatory network inC. glutamicum.
A Salmonella Type Three Secretion Effector/Chaperone Complex Adopts a Hexameric Ring-Like Structure
Authors: Roblin Pierre , Dewitte Frédérique , Villeret Vincent , Biondi Emanuele G. , Bompard Coralie
Published: November 2014

Many bacterial pathogens use type three secretion systems (T3SS) to inject virulence factors, named effectors, directly into the cytoplasm of target eukaryotic cells. Most of the T3SS components are conserved among plant and animal pathogens, suggesting a common mechanism of recognition and secretion of effectors. However, no common motif has yet been identified for effectors allowing T3SS recognition. In this work, we performed a biochemical and structural characterization of the
Salmonella
SopB/SigE chaperone/effector complex by small-angle X-ray scattering (SAXS). Our results showed that the SopB/SigE complex is assembled in dynamic homohexameric-ring-shaped structures with an internal tunnel. In this ring, the chaperone maintains a disordered N-terminal end of SopB molecules, in a good position to be reached and processed by the T3SS. This ring dimensionally fits the ring-organized molecules of the injectisome, including ATPase hexameric rings; this organization suggests that this structural feature is important for ATPase recognition by T3SS. Our work constitutes the first evidence of the oligomerization of an effector, analogous to the organization of the secretion machinery, obtained in solution. As effectors share neither sequence nor structural identity, the quaternary oligomeric structure could constitute a strategy evolved to promote the specificity and efficiency of T3SS recognition.
Ubiquitin Activates Patatin-Like Phospholipases from Multiple Bacterial Species
Authors: Anderson David M. , Sato Hiromi , Dirck Aaron T. , Feix Jimmy B. , Frank Dara W.
Published: November 2014

Phospholipase A2enzymes are ubiquitously distributed throughout the prokaryotic and eukaryotic kingdoms and are utilized in a wide array of cellular processes and physiological and immunological responses. Several patatin-like phospholipase homologs of ExoU fromPseudomonas aeruginosawere selected on the premise that ubiquitin activation of this class of bacterial enzymes was a conserved process. We found that ubiquitin activated all phospholipases tested in bothin vitroandin vivoassays via a conserved serine-aspartate catalytic dyad. Ubiquitin chains versus monomeric ubiquitin were superior in inducing catalysis, and ubiquitin-like proteins failed to activate phospholipase activity. Toxicity studies in a prokaryotic dual-expression system grouped the enzymes into high- and low-toxicity classes. Toxicity measured in eukaryotic cells also suggested a two-tiered classification but was not predictive of the severity of cellular damage, suggesting that each enzyme may correspond to unique properties perhaps based on its specific biological function. Additional studies on lipid binding preference suggest that some enzymes in this family may be differentially sensitive to phosphatidyl-4,5-bisphosphate in terms of catalytic activation enhancement and binding affinity. Further analysis of the function and amino acid sequences of this enzyme family may lead to a useful approach to formulating a unifying model of how these phospholipases behave after delivery into the cytoplasmic compartment.
A patient with mosaic neurofibromatosis type 2 presenting with early onset meningioma
Authors: Chu Yoyo Wing-Yiu , Cheuk Daniel Ka Leung , Chung Brian Hon Yin , Bowers Naomi L , Ha Shau-Yin , Chiang Alan Kwok-Shing , Chan Godfrey Chi-Fung
Published: November 2014

A female patient was found to have meningioma when she was 3 years and 11 months old and subtotal excision was performed. The residual tumour recurred 3 months after the first excision, and again 11 months after the second one. She was also found to have subcutaneous neurofibroma. However, her clinical features did not fulfil the diagnostic criteria for neurofibromatosis type 2 (NF2), and her family history was unremarkable. Considering that primary meningioma is extremely rare in the paediatric population, the diagnosis of NF2 was considered. It was thought that this might have an impact on her subsequent management. Genetic testing on blood DNA for NF2 was arranged, and the results confirmed that she had mosaic deletion of the promoter to exon 16 ofNF2. With uncertainty of whetherNF2mutations are also present in other tissues, vigilant follow-up for other NF2-related complications would be required in the future.
Imaging features of macrodystrophia lipomatosa: an unusual cause of a brawny arm
Authors: Dhanasekaran Jagadeesan , Reddy Ajit Kumar , Sarawagi Radha , Lakshmanan Prakash Manikka
Published: November 2014

Macrodystrophia lipomatosa (MDL), a rare non-hereditary congenital disorder of localised gigantism, is characterised by progressive proliferation of all mesenchymal elements, with a disproportionate increase in fibroadipose tissue. We report a case of a 19-year-old man who presented with a history of painless enlargement of the left upper limb since childhood, which was gradually increasing in size and predominantly involving the radial aspect of the upper limb with relative sparing of the ulnar aspect. The patient was imaged with X-ray and MRI. Imaging and clinical features were classical of MDL. The patient underwent stage 1 reduction plasty of the left forearm; preoperative and histopathological findings confirmed the preoperative diagnosis.
Psychophysiological response and energy balance during a 14-h ultraendurance mountain running event
Authors: Clemente-Suárez Vicente Javier
Published: November 2014

Many studies have researched the psychophysiological response and energy balance of athletes in numerous ultraendurance probes, but none has investigated an ultraendurance mountain running event. The current study aims to analyze changes in blood lactate concentration, rating of perceived exertion, heart rate, heart rate variability, and energy balance after the performance of an ultraendurance mountain running event. The parameters in the 6 participants who finished the event were analyzed (age, 30.8 ± 3.1 years; height, 176.2 ± 8.6 cm; body mass, 69.2 ± 3.7 kg). The race covered 54 km, with 6441 m of altitude change, 3556 m downhill and 2885 m uphill. The athletes completed together the race in 14 h and 6 min. After the ultraendurance event, the athletes presented a negative energy balance of 4732 kcal, a blood lactate concentration of 2.8 ± 0.3 mmol/L, a heart rate mean/heart rate maximum ratio of 0.64, a heart rate mean of 111.4 ± 5.9 beats/min, a decrease in vagal modulation, and an increase in sympathetic modulation, and recorded 19.5 ± 1.5 points on the 6–20 rating of perceived exertion scale. The event was a stressful stimulus for the athletes despite the low intensity measured by blood lactate concentration and heart rate. The results obtained may be used by coaches as a reference parameter of heart rate, heart rate variability, rating of perceived exertion, and lactate concentration to develop specific training programs. In addition, the energy balance data obtained in this research may improve nutritional intake strategies.
Anti-mycobacterial activities of copper(II) complexes. Part II. Lipophilic hydroxypyridinones derived from maltol
Authors: Salsbury Lauren E. , Robertson Katherine N. , Flewelling Andrew J. , Li Hoaxin , Geier Stephen J. , Vogels Christopher M. , Gray Christopher A. , Westcott Stephen A.
Published: November 2014

Eight lipophilic 3-hydroxy-4-pyridinones have been prepared from a microwave-mediated reaction along with the corresponding copper(II) complexes. All complexes have been obtained elementally pure and X-ray diffraction studies on two of the copper complexes have confirmed the structure of these compounds. Some of these complexes showed a promising degree of anti-mycobacterial activity against Mycobacterium tuberculosis, where activity seemed to vary by substitution at the pyridinone nitrogen atom.
A combination of pharmacophore modeling, molecular docking, and virtual screening for P2Y12 receptor antagonists from Chinese herbs
Authors: He Yusu , Jiang Ludi , Yang Zhen , Qiao Yanjiang , Zhang Yanling
Published: November 2014

P2Y12, a member of the G-protein-coupled receptors, is associated with abnormal platelet aggregation, a condition that contributes to thrombus formation. As receptor antagonists are effective solutions for anti-thrombus, the P2Y12 receptor is a popular drug target. After the recent resolution of the P2Y12 receptor’s crystal structure, pharmacophore modeling and docking were combined to discover potential natural antagonists. Various approaches were used for the validation of the pharmacophore models and the optimization of docking algorithms. Hypo18, which was generated by 24 known antagonists, was determined to be the best hypothesis and is comprised of one ring aromatic, one hydrogen bond acceptor, one exclude volume, and three hydrophobic features. Hypo18 was thus utilized to screen TCMD (version 2009) to identify any potential active compounds, which then resulted in a hit list of 121 compounds with drug-likeness analysis. In addition, docking was used to refine the pharmacophore-based screening results as a cross-linking method. Then, the top 20 compounds with high docking scores were reserved. This paper provides a reliable source for discovering natural P2Y12 receptor antagonists from traditional Chinese herbs.
Inflation as a white hole explosion from a 5D vacuum
Authors: Anabitarte Mariano , Bellini Mauricio
Published: November 2014

Using a new kind of 5D Ricci-flat canonical metric, we obtain by a static foliation an effective 4D Schwarzschild – de Sitter hypersurface. We examine some particular initial conditions that could be responsible for the inflationary expansion of the early universe, which could be driven by the explosion of a white hole (WH). The zeroth-order spectrum outside the WH describes quantum fluctuations, which for a scale invariant power spectrum, can be expressed in terms of the cosmological constant, or the square mass of the WH.
Host sex and parasitism in Red-winged Blackbirds (Agelaius phoeniceus): examining potential causes of infection biases in a sexually dimorphic species
Authors: Stewart T.E. , Merrill L.
Published: November 2014

Sex biases in parasitism rates are widely reported in the literature. Among vertebrates in particular, males are more frequently parasitized than females. These sex-linked differences are often attributed to different investment strategies in current versus future reproduction at the ultimate level and to different levels of circulating androgens at the proximate level. But there are other factors that can influence parasitism rates that are often neglected. In this study, we examined multiple measures of parasitism in male and female Red-winged Blackbirds (Agelaius phoeniceus (L., 1766)) to determine whether sex biases occur and sought to identify physiological and ecological factors that may be shaping such differences. We assessed three groups of parasites (ectoparasites, intestinal parasites, blood parasites), one measure of immune function (bacteria-killing ability), and diet. We found that male-biased infections were common only for intestinal parasites, but could not be attributed to dietary or immunological differences. We also found that immune function was associated with an individual’s infection status, appearing elevated in males infected with helminths. Our results suggest that, for this species, sex biases in parasitism do occur but are not the norm. Furthermore, their existence may depend on the nature of the host–parasite relationship.
Effect of randomness in logistic maps
Authors: Khaleque Abdul , Sen Parongama
Published: November 2014

We study a random logistic map xt+1 = atxt[1 - xt] where at are bounded (q1 ≤ at ≤ q2), random variables independently drawn from a distribution. xt does not show any regular behavior in time. We find that xt shows fully ergodic behavior when the maximum allowed value of at is 4. However 〈xt→∞〉, averaged over different realizations reaches a fixed point. For 1 ≤ at ≤ 4, the system shows nonchaotic behavior and the Lyapunov exponent is strongly dependent on the asymmetry of the distribution from which at is drawn. Chaotic behavior is seen to occur beyond a threshold value of q1(q2) when q2(q1) is varied. The most striking result is that the random map is chaotic even when q2 is less than the threshold value 3.5699⋯ at which chaos occurs in the nonrandom map. We also employ a different method in which a different set of random variables are used for the evolution of two initially identical x values, here the chaotic regime exists for all q1 ≠ q2 values.
Introduction to the special issue on "indirect dark matter searches"
Authors: Khlopov Maxim Yu.
Published: November 2014

The nature of cosmological dark matter finds its explanation in physics beyond the Standard Model of elementary particles. The landscape of dark matter candidates contains a wide variety of species, either elusive or hardly detectable in direct experimental searches. Even in case, when such searches are possible the interpretation of their results implies additional sources of information, which provide indirect effects of dark matter. Some nontrivial probes for the nature of the dark matter are presented in the present issue.
Cosmic ray excesses from multi-component dark matter decays
Authors: Geng Chao-Qiang , Huang Da , Tsai Lu-Hsing
Published: November 2014

We use multi-component decaying dark matter (DM) scenario to explain the possible cosmic ray excesses in the positron fraction recently confirmed by AMS-02 and the total e+ +e- flux observed by Fermi-LAT. In the two-component DM models, we find an interesting variation of the flavor structure along with the cutoff of the heavy DM. For the three-component DM case, we focus on a particular parameter range in which the best fits prefer to open only two DM decay channels with a third DM contributing nothing to the electron and positron spectra. We show that all models give the reasonable fits to both the AMS-02 positron fraction and the Fermi-LAT total e++e- flux, which are also consistent with the measured diffuse γ-ray flux by Fermi-LAT.
Nucleon mass splitting in the isospin medium
Authors: Lee Bum-Hoon , Mamedov Shahin , Park Chanyong
Published: November 2014

Using the AdS/CFT correspondence, we investigate a nucleon mass splitting and pion–nucleon coupling in the isospin medium. We find that there exists a nucleon mass splitting which is exactly given by the half of the meson mass splitting because nucleon has the half isospin charge of the charged mesons. In addition, we also investigate the pion–nucleon and four pion interactions which requires the modification of the known Abelian-type unitary gauge fixing because of the non-Abelian structure of the isospin medium. After finding the non-Abelian unitary gauge fixing, we find that in the isospin medium the couplings only for π0 π0 π+ π- and π0 π0π0 π0 of four pion interactions shift, while there is no pion–nucleon coupling splitting in spite of the nucleon's and meson's mass splittings.
Double-electron capture in collision of fast alpha particles with helium atoms
Authors: Ghanbari-Adivi Ebrahim , Ghavaminia Hoda
Published: November 2014

A four-body boundary-corrected first-order Jackson–Schiff approximation (JS1-4B) is developed to calculate the differential and integral cross-sections (DCSs) for double-electron exchange in collision of fast alpha ions with helium atoms in their ground states. The influence of the static electron correlations on cross-sections is taken into account through choosing the different wave functions to describe the initial and final bound states of the electrons. The quantum-mechanical post and prior transition amplitudes for double charge exchange are derived in terms of two-dimensional real integrals which can be calculated numerically. The validity and utility of the applied approach is critically assessed in comparison with the available experimental data for differential and integral cross-sections. The present calculations are also compared with the results obtained from the other theories.
Emerging quantum mechanics: Coefficient of second-order coherence from classical random fields interacting with threshold type detectors
Authors: Khrennikov Andrei
Published: November 2014

This paper is a contribution to the project "emergent quantum mechanics" unifying a variety of attempts to treat quantum mechanics (QMs) as emergent from other theories pretending on finer descriptions of quantum phenomena. More concretely it is about an attempt to model detection probabilities predicted by QM for single photon states by using classical random fields interacting with detectors of the threshold type. Continuous field model, prequantum classical statistical field theory (PCSFT), was developed in recent years and its predictions about probabilities and correlations match well with QM. The main problem is to develop the corresponding measurement theory which would describe the transition from continuous fields to discrete events, "clicks of detectors". Some success was achieved and the click-probabilities for quantum observables can be derived from PCSFT by modeling interaction of fields with the threshold type detectors. However, already for the coefficient of second-order coherence g2(0) calculations are too complicated and only an estimation of g2(0) was obtained. In this paper, we present results of numerical simulation based on PCSFT and modeling of interaction with threshold type detectors. The "prequantum random field" interacting with a detector is modeled as the Brownian motion in the space of classical fields (Wiener process in complex Hilbert space). Simulation for g2(0) shows that this coefficient approaches zero with increase of the number of detections.
Knowledge Transfer Mechanisms and Global R&D Operations in MNCs
Authors: Song Nan , Zhu Jinping , Rundquist Jonas
Published: November 2014

With the development of globalization, companies will need worldwide resources for R&D. Multinational corporations (MNCs) will rely on their subunits located in different countries for R&D. As a result, knowledge transfer between headquarters and subunits or among subunits will be crucial for MNCs to operate their R&D activities. This study explores the relationship between knowledge transfer and R&D operations, using a qualitative research approach including four multinational companies. We conducted a cross-case analysis connecting four R&D configurations and two knowledge transfer mechanisms: expatriate management policy and communication frequency. Results show that both transfer mechanisms are very important for MNCs for the management of knowledge transfer in global R&D operations. However, each of these mechanisms will need a different focus depending on R&D strategy and configuration. The paper summarizes recommendations for managers as drawn from these insights.
Metal molybdate nanorods as non-precious electrocatalysts for the oxygen reduction
Authors: Wu Tian , Zhang Lieyu
Published: November 2014

Development of non-precious electrocatalysts with applicable electrocatalytic activity towards the oxygen reduction reaction (ORR) is important to fulfill broad-based and large-scale applications of metal/air batteries and fuel cells. Herein, nickel and cobalt molybdates with uniform nanorod morphology are synthesized using a facile one-pot hydrothermal method. The ORR activity of the prepared metal molybdate nanorods in alkaline media are investigated by using cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperomety in rotating disk electrode (RDE) techniques. The present study suggests that the prepared metal molybdate nanorods exhibit applicable electrocatalytic activities towards the ORR in alkaline media, promising the applications as non-precious cathode in fuel cells and metal–air batteries.
Enhancement effects of two kinds of carbon black on piezoelectricity of PVDF-HFP composite films
Authors: Hu Bin , Hu Ning , Wu Liangke , Cui Hao , Ying Ji
Published: November 2014

Two kinds of carbon black (CB) (i.e., CB#300 and CB#3350) were added into poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP), respectively, to improve its piezoelectricity. The results revealed that when 0.5 wt.% CB was added, the best performance of the PVDF-HFP/CB composite films was obtained. The calibrated open circuit voltage and the density of harvested power of 0.5 wt.% CB#3350 contained composite films were 204%, and 464% (AC) and 561% (DC) of those of neat PVDF-HFP films. Similarly, for 0.5 wt.% CB#300 contained films, they were 211%, and 475% (AC) and 624% (DC), respectively. The enhancement mechanisms of piezoelectricity were clarified by the observation of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and scanning electron microscope (SEM). We found that the added CBs act as nucleate agents to promote the formation of elongated, oriented and fibrillar β-phase crystals during the fabrication process, which increase the piezoelectricity. Overdosed CBs lead to a lower crystallinity degree, resulting in the lower piezoelectricity. Compared with CB#3350, CB#300 performs slightly better, which may be ascribed to its higher specific surface area.
THE NUMERICAL SIMULATION OF UNSTEADY CAVITATION EVOLUTION INDUCED BY PRESSURE WAVE
Authors: KHOO B.C. , ZHENG J.G.
Published: November 2014

The present study is focused on the numerical simulation of pressure wave propagation through the cavitating compressible liquid flow, its interaction with cavitation bubble and the resulting unsteady cavitation evolution. The compressibility effects of liquid water are taken into account and the cavitating flow is governed by one-fluid cavitation model which is based on the compressible Euler equations with the assumption that the cavitation is the homogeneous mixture of liquid and vapour which are locally under both kinetic and thermodynamic equilibrium. Several aspects of the method employed to solve the governing equations are outlined. The unsteady features of cavitating flow due to the external perturbation, such as the cavitation deformation and collapse and consequent pressure increase are resolved numerically and discussed in detail. It is observed that the cavitation bubble collapse is accompanied by the huge pressure surge of order of 100 bar, which is thought to be responsible for the material erosion, noise, vibration and loss of efficiency of operating underwater devices.
TURBULENCE DRIVEN BY FARADAY SURFACE WAVES
Authors: SHATS MICHAEL , FRANCOIS NICOLAS , XIA HUA , PUNZMANN HORST
Published: November 2014

We report experimental results which show that the particle motion on the surface perturbed by Faraday waves is similar to the fluid motion in 2D turbulence. It supports the inverse energy cascade or the spectral energy transfer from smaller to larger scales. The vertical acceleration ranges from the Faraday instability threshold up to the droplet nucleation threshold where the ripples are a couple of millimeters high. Such a configuration rules out any 2D assumption on the fluid motion. The motion of floaters on the surface of the Faraday waves is essentially three dimensional but its horizontal component shows unexpected analogy with two-dimensional turbulence. The presence of the inverse cascade is detected by measuring frequency spectra of the Lagrangian velocity and confirmed by computing the third moment of the horizontal Eulerian velocity fluctuations. This is a robust phenomenon observed in deep water in a broad range of flow energies and wavelengths. The emergence of such a phenomenology in Faraday waves broadens the applicability of features common to 2D turbulent flows to the context of surface wave phenomena which is prevalent in many systems.
CALCULATION OF ACOUSTIC RADIATION FORCE AND MOMENT IN MICROFLUIDIC DEVICES
Authors: LIM KIAN-MENG , RAHNAMA SHAHROKH SEPEHRI
Published: November 2014

The ability to compute the acoustic radiation force and torque acting on a particle is critical to the design of microfluidic devices and the operating conditions for separation of different species of particles or biological cells using this force field. Closed-form formulae had been reported in the literature for calculating the acoustic radiation force acting on simple geometries such as spheres and ellipsoids. Also, these analytical formulae are limited to objects that are small compared to the wavelength of sound in the surrounding fluid. Numerical methods provide a more flexible way to calculate the acoustic radiation force and torque on suspended objects of arbitrary shape and size. In this paper, we will present results of using the finite element method and the multipole expansion method to calculate the acoustic radiation force and moment. For harmonic excitation, the Helmholtz equation is solved for the velocity potential of the acoustic field with the appropriate boundary conditions imposed on the surface of the spherical or ellipsoidal objects. The resultant force and torque were then calculated by performing a surface integral of the second order, time-averaged Brillouin stress over the object. The numerical results show good agreement with the analytical results for small size spheres and ellipsoids. When the object size is comparable to the wavelength of the acoustic field, the analytical results breakdown and numerical methods are necessary to obtain accurate results.
THERMO-CHEMICAL NONEQUILIBRIUM PHENOMENA OF THE STRONG SHOCK WAVE TO GENERATE HYPERVELOCITY TEST FLOW
Authors: MIN HU ZONG , CHUN WANG , LIN JIANG ZONG , CHEONG KHOO BOO
Published: November 2014

To generate the hypervelocity (above 5 km/s) test flow for the experimental study of reentry physics, a shock-expansion tube or tunnel is the only qualified test facility by far. In such a facility, the working gas shall be compressed by an extremely strong shock wave, e.g., Ms=27.7 for the 8 km/s test condition. Therefore, thermo-chemical nonequilibrium phenomena may occur in the gas post the shock wave. Such phenomena, consequently, can incur difficulties in diagnostic and measurement to experimental study, and instability problems to numerical analysis on the other hand. The present paper will focus on the numeric-aid diagnostics of the flow conditions.
A Learning-Based Approach to Confident Event Detection in Heterogeneous Sensor Networks
Authors: Keally Matthew , Zhou Gang , Xing Guoliang , Nguyen David T. , Qi Xin
Published: November 2014

Wireless sensor network applications, such as those for natural disaster warning, vehicular traffic monitoring, and surveillance, have stringent accuracy requirements for detecting or classifying events and demand long system lifetimes. Through quantitative study, we show that existing event detection approaches are challenged to explore the sensing capability of a deployed system and choose the right sensors to meet user-specified accuracy. Event detection systems are also challenged to provide a generic system that efficiently adapts to environmental dynamics and works easily with a range of applications, machine learning approaches, and sensor modalities. Consequently, we propose Watchdog, a modality-agnostic event detection framework that clusters the right sensors to meet user-specified detection accuracy during runtime while significantly reducing energy consumption. Watchdog can use different machine learning techniques to learn the sensing capability of a heterogeneous sensor deployment and meet accuracy requirements. To address environmental dynamics and ensure energy savings, Watchdog wakes up and puts to sleep sensors as needed to meet user-specified accuracy. Through evaluation with real vehicle detection trace data and a building traffic monitoring testbed of IRIS motes, we demonstrate the superior performance of Watchdog over existing solutions in terms of meeting user-specified detection accuracy, energy savings, and environmental adaptability.
Sequentially Constructive Concurrency—A Conservative Extension of the Synchronous Model of Computation
Authors: Hanxleden Reinhard Von , Mendler Michael , Aguado Joaquín , Duderstadt Björn , Fuhrmann Insa , Motika Christian , Mercer Stephen , O'brien Owen , Roop Partha
Published: November 2014

Synchronous languages ensure determinate concurrency but at the price of restrictions on what programs are considered valid, or
constructive
. Meanwhile, sequential languages such as C and Java offer an intuitive, familiar programming paradigm but provide no guarantees with regard to determinate concurrency. The
sequentially constructive
(SC) model of computation (MoC) presented here harnesses the synchronous execution model to achieve determinate concurrency while taking advantage of familiar, convenient programming paradigms from sequential languages.

In essence, the SC MoC extends the classical synchronous MoC by allowing variables to be read and written in any order and multiple times, as long as the sequentiality expressed in the program provides sufficient scheduling information to rule out race conditions. This allows to use programming patterns familiar from sequential programming, such as testing and later setting the value of a variable, which are forbidden in the standard synchronous MoC. The SC MoC is a conservative extension in that programs considered constructive in the common synchronous MoC are also SC and retain the same semantics. In this article, we investigate classes of shared variable accesses, define SC-admissible scheduling as a restriction of “free scheduling,” derive the concept of sequential constructiveness, and present a priority-based scheduling algorithm for analyzing and compiling SC programs efficiently.
Incremental Bisimulation Abstraction Refinement
Authors: Song Lei , Zhang Lijun , Hermanns Holger , Godskesen Jens CHR.
Published: November 2014

Abstraction refinement techniques in probabilistic model checking are prominent approaches for verification of very large or infinite-state probabilistic concurrent systems. At the core of the refinement step lies the implicit or explicit analysis of a counterexample. This article proposes an abstraction refinement approach for the probabilistic computation tree logic (PCTL), which is based on incrementally computing a sequence of may- and must-quotient automata. These are induced by depth-bounded bisimulation equivalences of increasing depth. The approach is both sound and complete, since the equivalences converge to the genuine PCTL equivalence. Experimental results with a prototype implementation show the effectiveness of the approach.
Garbage-Free Reversible Multipliers for Arbitrary Constants
Authors: Mogensen Torben Ægidius
Published: November 2014

We present a method based on Mealy machines for constructing reversible circuitry for multiplying integers by arbitrary integer constants. The circuits generate no garbage and use no ancillae. The circuits are quite compact for small constants and are, in the worst case, bounded by O(
n
2
) multi-control Toffoli gates per bit-slice, where
n
is the number of bits in the constant. These gates will have O(
n
) inputs, so the total number of pass-transistors needed to implement the circuit is O(
n
3
) transistors per bit slice, and the quantum cost (which is exponential in the number of inputs to a Toffoli gate) is O(2

n

).

For some interesting cases, the cost can be reduced to O(
n
) gates per bit-slice, reducing the cost to O(
n
2
) transistors per bit slice. The quantum cost is still O(2

n

), as the remaining gates have O(
n
) inputs.

We also look at an alternative construction that, at the cost of adding O(
n
) ancillae, reduces the cost for arbitrary constants to O(
n
) gates, O(
n
2
) transistors, though still with O(2

n

) quantum cost.
Quantifying Irreversible Information Loss in Digital Circuits
Authors: Hänninen Ismo K. , Lent Craig S. , Snider Gregory L.
Published: November 2014

Heat generation limits the performance of state-of-the-art integrated circuits, originating from the wasteful static CMOS operating principle. Near-term solutions like adiabatic charging for energy recovery and limiting friction-type heat sources provide considerable improvement. However, these methods do not address the ultimate thermodynamic necessity to expel energy related to information loss in the computing process. In emerging beyond-CMOS technologies, this bit erasure heat alone can overwhelm the cooling capacity and set the limits of the computing performance. Therefore, logical information loss is becoming an important factor for digital circuit design, and tools have to be developed for analysis and optimization. This article presents a framework for estimating the amount of information loss in complex logic circuits, demonstrating the method by modeling the irreversible bit erasures in a standard binary adder structure. Binary addition is one of the most often used and highly optimized digital designs, and we estimate the erasure bounds for components on various levels of design abstraction, showing that the actual logic gate implementations have orders of magnitude higher loss than the addition operation itself would require. The method and the results can be used to optimize circuits for a higher degree of logical reversibility and energy conservation.
An Improved Reversible Circuit Synthesis Approach using Clustering of ESOP Cubes
Authors: Datta Kamalika , Rathi Gaurav , Sengupta Indranil , Rahaman Hafizur
Published: November 2014

The problem of reversible logic synthesis has drawn the attention of many researchers over the last two decades with growing emphasis on low-power design. Among the various synthesis approaches that have been reported, the ones based on compact circuit representations like Binary Decision Diagrams (BDD) and Exclusive-or Sum-Of-Products (ESOP) are interesting in the sense that they can handle large circuits with more than 100 inputs. The drawback of these approaches, however, is that the generated netlists are sub-optimal, and there is lot of scope for optimizing them. One of the best methods in this regard is an approach, where the ESOP cubes are grouped into sublists based on sharing among more than one outputs. In the work reported in this article, in contrast, an approach based on clustering the ESOP cubes based on their similarity with respect to input variables is presented, along with a technique to map each of the clusters into reversible gate netlists. This approach results in a significant reduction in quantum cost of the final netlist, but requires one additional garbage line. Experimental results on a number of reversible circuit benchmarks have been presented in support of the claim and also demonstrate that the method is very fast.
Constructing and Comparing User Mobility Profiles
Authors: Chen Xihui , Pang Jun , Xue Ran
Published: November 2014

Nowadays, the accumulation of people's whereabouts due to location-based applications has made it possible to construct their mobility profiles. This access to users' mobility profiles subsequently brings benefits back to location-based applications. For instance, in on-line social networks, friends can be recommended not only based on the similarity between their registered information, for instance, hobbies and professions but also referring to the similarity between their mobility profiles.

In this article, we propose a new approach to construct and compare users' mobility profiles. First, we improve and apply
frequent sequential pattern mining
technologies to extract the sequences of places that a user frequently visits and use them to model his mobility profile. Second, we present a new method to calculate the similarity between two users using their mobility profiles. More specifically, we identify the weaknesses of a similarity metric in the literature, and propose a new one which not only fixes the weaknesses but also provides more precise and effective similarity estimation. Third, we consider the semantics of spatio-temporal information contained in user mobility profiles and add them into the calculation of user similarity. It enables us to measure users' similarity from different perspectives. Two specific types of semantics are explored in this article:
location semantics
and
temporal semantics
. Last, we validate our approach by applying it to two real-life datasets collected by Microsoft Research Asia and Yonsei University, respectively. The results show that our approach outperforms the existing works from several aspects.
Sentiment-Focused Web Crawling
Authors: Vural A. Gural , Cambazoglu B. Barla , Karagoz Pinar
Published: November 2014

Sentiments and opinions expressed in Web pages towards objects, entities, and products constitute an important portion of the textual content available in the Web. In the last decade, the analysis of such content has gained importance due to its high potential for monetization. Despite the vast interest in sentiment analysis, somewhat surprisingly, the discovery of sentimental or opinionated Web content is mostly ignored. This work aims to fill this gap and addresses the problem of quickly discovering and fetching the sentimental content present in the Web. To this end, we design a sentiment-focused Web crawling framework. In particular, we propose different sentiment-focused Web crawling strategies that prioritize discovered URLs based on their predicted sentiment scores. Through simulations, these strategies are shown to achieve considerable performance improvement over general-purpose Web crawling strategies in discovery of sentimental Web content.
Automated Generation of Music Playlists: Survey and Experiments
Authors: Bonnin Geoffray , Jannach Dietmar
Published: November 2014

Most of the time when we listen to music on the radio or on our portable devices, the order in which the tracks are played is governed by so-called playlists. These playlists are basically sequences of tracks that traditionally are designed manually and whose organization is based on some underlying logic or theme. With the digitalization of music and the availability of various types of additional track-related information on the Web, new opportunities have emerged on how to automate the playlist creation process. Correspondingly, a number of proposals for automated playlist generation have been made in the literature during the past decade. These approaches vary both with respect to which kind of data they rely on and which types of algorithms they use. In this article, we review the literature on automated playlist generation and categorize the existing approaches. Furthermore, we discuss the evaluation designs that are used today in research to assess the quality of the generated playlists. Finally, we report the results of a comparative evaluation of typical playlist generation schemes based on historical data. Our results show that track and artist popularity can play a dominant role and that additional measures are required to better characterize and compare the quality of automatically generated playlists.
A Scheduling Framework for Spatial Architectures Across Multiple Constraint-Solving Theories
Authors: Nowatzki Tony , Sartin-Tarm Michael , De Carli Lorenzo , Sankaralingam Karthikeyan , Estan Cristian , Robatmili Behnam
Published: November 2014

Spatial architectures provide energy-efficient computation but require effective scheduling algorithms. Existing heuristic-based approaches offer low compiler/architect productivity, little optimality insight, and low architectural portability.

We seek to develop a spatial-scheduling framework by utilizing constraint-solving theories and find that architecture primitives and scheduler responsibilities can be related through five abstractions: computation placement, data routing, event timing, resource utilization, and the optimization objective. We encode these responsibilities as 20 mathematical constraints, using SMT and ILP, and create schedulers for the TRIPS, DySER, and PLUG architectures. Our results show that a general declarative approach using constraint solving is implementable, is practical, and can outperform specialized schedulers.
Anisotropic simplicial meshing using local convex functions
Authors: Fu Xiao-Ming , Liu Yang , Snyder John , Guo Baining
Published: November 2014

We present a novel method to generate high-quality simplicial meshes with specified anisotropy. Given a surface or volumetric domain equipped with a Riemannian metric that encodes the desired anisotropy, we transform the problem to one of functional approximation. We construct a convex function over each mesh simplex whose Hessian locally matches the Riemannian metric, and iteratively adapt vertex positions and mesh connectivity to minimize the difference between the target convex functions and their piecewise-linear interpolation over the mesh. Our method generalizes optimal Delaunay triangulation and leads to a simple and efficient algorithm. We demonstrate its quality and speed compared to state-of-the-art methods on a variety of domains and metrics.
Automatic semantic modeling of indoor scenes from low-quality RGB-D data using contextual information
Authors: Chen Kang , Lai Yu-Kun , Wu Yu-Xin , Martin Ralph , Hu Shi-Min
Published: November 2014

We present a novel solution to automatic semantic modeling of indoor scenes from a sparse set of low-quality RGB-D images. Such data presents challenges due to noise, low resolution, occlusion and missing depth information. We exploit the knowledge in a scene database containing 100s of indoor scenes with over 10,000 manually segmented and labeled mesh models of objects. In seconds, we output a visually plausible 3D scene, adapting these models and their parts to fit the input scans. Contextual relationships learned from the database are used to constrain reconstruction, ensuring semantic compatibility between both object models and parts. Small objects and objects with incomplete depth information which are difficult to recover reliably are processed with a two-stage approach. Major objects are recognized first, providing a known scene structure. 2D contour-based model retrieval is then used to recover smaller objects. Evaluations using our own data and two public datasets show that our approach can model typical real-world indoor scenes efficiently and robustly.
Slippage-free background replacement for hand-held video
Authors: Zhong Fan , Yang Song , Qin Xueying , Lischinski Dani , Cohen-Or Daniel , Chen Baoquan
Published: November 2014

We introduce a method for replacing the background in a video of a moving foreground subject, when both the
source video
capturing the subject, and the
target video
capturing the new background scene, are natural videos, casually captured using a freely moving hand-held camera. We assume that the foreground subject has already been extracted, and focus on the challenging task of generating a video with a new background, such that the new background motion appears compatible with the original one. Failure to match the motion results in disturbing
slippage
or
moonwalk
artifacts, where the subject's feet appear to slide or slip over the ground. While matching the motion across the entire frame is impossible for scenes with differing geometry, we aim to match the
local motion
of the ground in the vicinity of the subject. This is achieved by reordering and warping the available target background frames in a manner that optimizes a suitably designed objective function.
Site-Specific Models for Realistic Wireless Network Simulation
Authors: Sengul Cigdem , Al-Bado Mustafa , Feldmann Anja
Published: November 2014

The utility of simulation-based performance evaluation for wireless networking has been under scrutiny as the community relies increasingly on testbed-based performance evaluations. While testbeds are invaluable tools for realistic network and protocol evaluation, these results are generally obtained after cumbersome system implementation and debugging. On the other hand, realistic simulation models can reduce the time and effort for
concept testing
of ideas. To this end, we develop BOWLsim PHY layer models—propagation, frame detection, and frame error models—based on extensive measurements in the Berlin Open Wireless Lab indoor and outdoor testbeds. Our models are integrated into the ns-3 simulator. We run an extensive measurement and simulation study, which illustrates that BOWLsim models represent network conditions at the physical (PHY) layer and transport layer accurately.
EXIP
Authors: Kyusakov Rumen , Pereira Pablo Puñal , Eliasson Jens , Delsing Jerker
Published: November 2014

Developing and deploying Web applications on networked embedded devices is often seen as a way to reduce the development cost and time to market for new target platforms. However, the size of the messages and the processing requirements of today's Web protocols, such as HTTP and XML, are challenging for the most resource-constrained class of devices that could also benefit from Web connectivity.

New Web protocols using binary representations have been proposed for addressing this issue. Constrained Application Protocol (CoAP) reduces the bandwidth and processing requirements compared to HTTP while preserving the core concepts of the Web architecture. Similarly, Efficient XML Interchange (EXI) format has been standardized for reducing the size and processing time for XML structured information. Nevertheless, the adoption of these technologies is lagging behind due to lack of support from Web browsers and current Web development toolkits.

Motivated by these problems, this article presents the design and implementation techniques for the EXIP framework for embedded Web development. The framework consists of a highly efficient EXI processor, a tool for EXI data binding based on templates, and a CoAP/EXI/XHTML Web page engine. A prototype implementation of the EXI processor is herein presented and evaluated. It can be applied to Web browsers or thin server platforms using XHTML and Web services for supporting human-machine interactions in the Internet of Things.

This article contains four major results: (1) theoretical and practical evaluation of the use of binary protocols for embedded Web programming; (2) a novel method for generation of EXI grammars based on XML Schema definitions; (3) an algorithm for grammar concatenation that produces normalized EXI grammars directly, and hence reduces the number of iterations during grammar generation; (4) an algorithm for efficient representation of possible deviations from the XML schema.