bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-Scale Near-Wall Averaging and Two-Phase Logarithmic Law for a CFD Two-Fluid Model
Authors: Vaidheeswaran Avinash , Buchanan John R. , Guilbert Paul , Lopez de Bertodano Martin
Published: December 2014

A considerable amount of work has been done in the past to improve the solution methodology using the two-fluid model in the near-wall region. This includes the works of Larrateguy et al. [1], and Moraga et al. [2], based on a multi-scale bubble-center averaging technique. However one shortcoming is that the primitive variables must be recovered from the bubble-center averaged variables. This makes it difficult to implement it in a commercial CFD code. The current research focuses on an engineering approach to overcome this issue. A multi-scale near-wall averaging technique is proposed which separates the effects of bubble dynamics from its geometry in this region.

In addition, the averaged volume fraction profile makes the CFD approach consistent with the modified logarithmic law of Marie et al. [3]. A step function volume fraction distribution was assumed in the near-wall region while developing the theory. However, the volume fraction prediction obtained from CFD calculations is not uniform in this region. The proposed near-wall averaging technique resolves this issue and makes the CFD implementation of the modified wall function approach consistent with the theory of Marie et al. [3].
CFD and Heat Transfer Analysis of Vortex Formation in a Solar Reactor
Authors: Chien Min-Hsiu , Ozalp Nesrin , Morrison Gerald
Published: December 2014

A hydrogen producing solar reactor was experimentally tested to study the cyclone flow dynamics of the gas-particle two-phase phenomenon. Two dimensional PIV (particle image velocimetry) was used to observe the flow and to quantify the vortex formation inside the solar reactor. The vortex flow structure in the reactor was reconstructed by capturing images from orientations perpendicular and parallel to the geometrical axis of the reactor respectively. The experimental results showed that the tangential components of the fluid velocity formed a Rankine-vortex profile. The free vortex portions of the Rankine profile were synchronized and independent of the axial position. The axial components showed a vortex funnel of higher speed fluid supplied by a reversing secondary flow. According to the inlet channel design, the geometry dominates the flow dynamics. A stable precessing vortex line was observed. As the vortex flow evolves towards the exit, the vortex funnel expands radially with decreasing tangential velocity magnitude peak as a result of the vortex stretching. An optimal residence time of the flow was found by changing the cyclone flow inlet conditions. The swirl number versus the main flow rate change was obtained. Upon the completion of the experimental studies, a thorough numerical analysis was conducted to model the flow dynamics inside the solar reactor and to verify the results by comparison to the experimental results. Three turbulence models including the standard k-ε, k-ε RNG and Reynolds Stress Transport models were used. CFD simulations were coupled with heat transfer analysis via Discrete Ordinate model. Particle tracing in Lagrange frame was applied to simulate the particle trajectory. A comparison between the turbulence modeling results for the room temperature and high temperature cases, as well as the experimental results for room temperature cases is presented.
Numerical Simulation of Turbulent Spray Flows Using Transported PDF Methods
Authors: Hu Yong , Gutheil Eva
Published: December 2014

This paper presents a numerical study of a turbulent acetone spray flow, where the gas phase model includes a transported joint probability density function (PDF) of the gas phase velocity and the mixture fraction. This approach greatly benefits from the fact that the spray evaporation rate appears in closed form, and no additional modeling is required, whereas the molecular mixing requires closure. This is achieved through use of the extended interaction-by-exchange-with-the-mean (IEM) model with an additional term to account for spray evaporation. The dispersed liquid phase is described through a Lagrangian discrete parcel method with a point-source approximation. For droplet evaporation, an equilibrium model is compared with a more advanced non-equilibrium model. Numerical results of droplet size as well as mean and fluctuating velocities are presented and discussed in comparison with experimental results from the literature, and good agreement is observed. The non-equilibrium model predicts somewhat slower spray evaporation compared with the equilibrium model.
On Topology Dependence of Explosive Shock Properties
Authors: Costain Andrew , Bayandor Javid
Published: December 2014

When explosive material is ignited, a detonation wave is generated causing a chemical reaction to take place. This chemical reaction results in the creation of a shockwave in the air surrounding the explosive material. The properties of this shockwave are dependent upon many different variables including but not limited to the type of explosive material used, the amount of material used, the surrounding fluid and the distance that the shockwave travels from the point of ignition. One variable that is not often considered is how the topology of the explosive material may affect the properties of a shockwave. If all other properties are held constant, the shockwave created by a spherical explosive charge will have different properties from those created by a cylindrical or cubical charge. This work uniquely applies an explicit finite element approach to simulate different shapes of explosives and the effects of explosive surface topology on the ensuing shockwaves. In order to fully observe these varying shockwaves, a target wall was included in the simulations. The propagating shockwaves damage the wall on impact, while creating a series of reflective shock- and strain-waves. By thoroughly examining the damaged portions of the target wall in conjunction with wave propagation patterns, it is possible to study the strength of the shockwave and the mechanism by which the reflective waves are created. Through these investigations, shockwave pressure, velocity, patterns and shapes, as well as damage sustained by the wall will be considered. The paper will conclude how shockwave properties are influenced by the original topology of the explosive mass.
Multi-Scale Simulation of Reactive Flow Through a Fixed Bed of Catalyst Particles
Authors: Dorai Ferdaous , Briquet Ludovic , Hammouti Abdelkader , Rolland Matthieu , Wachs Anthony
Published: December 2014

We investigate the reactive flow through a fixed bed of catalyst particles. Our simulation method belongs to the class of multi-scale approaches and combines nano scale DFT (Density Functional Theory) computations, mean-field kinetics at the micro scale and fully-resolved hydrodynamic simulations at the millimetric scale. At this stage, the simulations at the chemical (nano and micro) scales provide the rate constants needed by the hydrodynamic model in a one-way coupling. In this paper, we focus on the fully-resolved millimetric scale simulation model based on a Distributed Lagrange Multiplier/Fictitious Domain (DLM/FD) method combined with a Finite Volume/Staggered Grid scheme and a high order reconstruction at the fluid/solid interface. In particular, we present various DLM/FD algorithms that supply a divergence free velocity field, a property crucial for the accurate discretization of the additional diffusion-convection equations modeling the chemical reactions. Our method is implemented in our fully MPI platform PeliGRIFF (www.peligriff.com) dedicated to the multi-scale simulation of flows with particles/bubbles/drops. We illustrate the assets of our simulation method on the reactive flow through a pack of 3D cylinders and discuss the forthcoming developments required to extend our approach to a two-way coupling in which the reaction rates are affected by the flow dynamics.
Limitations of and Alternatives to Traditional Uncertainty Quantification for Measurements
Authors: Smith Barton L. , Oberkampf William L.
Published: December 2014

Measurement uncertainty of quantities that are functions of more than one measured variable are usually determined using propagation methods; either the Taylor Series Method or the Monte Carlo Method. Each of these requires critical assumptions that are more sweeping and potentially dangerous than commonly realized. The implications of these assumptions is explained along with some examples of how violation of these assumptions invalidates the uncertainty estimate. A new perspective based on consideration of potential error sources is presented ranging from the physical system being measured, the measurement system, the data reduction system, to the final experimental measurement result. An alternative approach that relies on sampling of error sources, whether known or unknown, is demonstrated through several examples. These examples demonstrate that the alternative approach can provide a more realistic estimate of total experimental uncertainty; one which is commonly much larger than that provided by traditional propagation methods.
Turbulent Flow-Field Comparisons of RANS and LES for a Twisted Pin Lattice Geometry at Low Reynolds Number
Authors: Kraus Adam R. , Merzari Elia , Fischer Paul F.
Published: December 2014

The accurate evaluation of fuel and cladding peak temperatures is of prime importance for nuclear reactor design and safety. The Global Threat Reduction Initiative reactor conversion program often encounters exotic flow geometries in its mission to aid in converting reactors from high-enriched to low-enriched fuel. These geometries can pose modeling challenges. Analysis presented here concerns a reactor with twisted fuel pins that are in direct contact with each other in a large, hexagonal-pitch lattice. The Reynolds number for a unit cell is only 7500. Such flow conditions can present difficulties for standard approaches based on Reynolds-Averaged Navier-Stokes (RANS). Moreover there are no available experimental data and a small expected margin to the limiting cladding surface temperature. Given some of the geometric uncertainties, reducing the turbulence model uncertainty is thus important for meaningful calculations. A computational fluid dynamics model of a full-length unit cell was built using the commercial code STAR-CCM+. Multiple RANS models were employed, which gave disparate results. To provide higher-fidelity data for comparison, given the lack of experimental data, a periodic single-helical-pitch simulation with a Large Eddy Simulation (LES) approach was performed using Nek5000, a massively-parallel spectral-element code. This was compared with single-pitch RANS simulations from STAR-CCM+. Stream-wise velocity profile shape was generally well-represented by RANS. Cross-velocities and peak turbulent kinetic energy (TKE) were underestimated for most of the turbulence models with respect to LES, while mean flow TKE was universally underestimated. The overall results suggest that the Realizable k-ε Two-Layer model, which was the best at reproducing the LES TKE distribution, would likely be the most appropriate turbulence model choice for this flow. Future work includes full conjugate heat transfer simulations of 1/6 sectors of fuel assemblies featuring this type of pin lattice.
Influence of Guide Vane Shapes on Hydraulic Characteristics for a Shaft-Extension Tubular Pump Turbine at Turbine Mode
Authors: Huang Renfang , Luo Xianwu , Ji Bin , Zheng Yuan
Published: December 2014

Guide vanes are important components for a shaft-extension tubular pump turbine. To study the influence of guide vanes on the performance of a shaft-extension tubular pump turbine, three guide vanes with different section profiles are prepared. The steady flows through the whole passage of the shaft-extension tubular pump turbine with different guide vanes are simulated based on RNG k-ε turbulence model. The numerical results show that the section profile of a guide vane influences the hydraulic performance of the pump turbine. It is noted that the pump turbine with the guide vane profile having a large curvature has a broader operation range with high efficiency, and the minimal hydraulic loss among three guide vanes. Further investigation depicts that the static pressure and velocity distribution in the guide vane are relatively uniform, and there are hardly flow incidence at the leading edge and little low pressure zone near the suction side for the suitable guide vane profile.
Flexible Turbulence Absorbers for Enhancing the Liquid Flow in Pipelines
Authors: Abdulbari Hayder A. , Yunus Rosli Bin Mohd , Charles Ashwin
Published: December 2014

In the present work, an additive-free new technique for enhancing the flow in pipelines is introduced. Such technique depends on inserting Turbulence Altering Pseudo-Surface, TAPS with certain dimensions inside the pipe (adjacent to the inner wall). Such technique is meant to simulate the viscoelastic behaviour of soluble additives to enhance the flow in pipelines. Liquid circulation system with a testing section divided into four subsections was used to test the drag reduction effect of the new technique. The results showed that almost 60% flow enhancement is achievable when inserting 12 strips with 60 cm length into 0.0381 m diameter pipe.
Image Adaptive Thresholding for Multiphase Wavy Flow
Authors: Al-Nasser Mustafa , Elshafei Moustafa , Al-Sarkhi Abdelsalam
Published: December 2014

Multiphase flow measurement is a very challenging issue in process industry. One of the promising approaches for multiphase flow analysis is image processing. Image segmentation is very important step in multiphase flow analysis. Determination of appropriate threshold value is very critical step for correct identification of the liquid and gas phases. There are two main thresholding techniques: Global and Adaptive. Adaptive thresholding is more suitable for multiphase flow case due to it’s adaptability to image conditions such non-uniform illumination and noise. In this work, six adaptive thresholding techniques are examined for the case of wavy flow regime. These algorithms are used to estimate the wave shape and mix region between liquid and gas. In general, the adaptive algorithms are able to compensate for non-uniform illumination and they are able to estimate wave shape and mix region correctly. The execution time for the adaptive techniques is higher than global thresholding technique, but with the availability of new powerful PCs, it will become a minor issue.
Association of Muscle-Strengthening Activity With Knee and Low Back Pain, Falls, and Health-related Quality of Life Among Japanese Older Adults: A Cross-sectional Survey
Authors: Harada Kazuhiro , Shibata Ai , Oka Koichiro , Nakamura Yoshio
Published: December 2014

This study aimed to examine the association of muscle-strengthening activity with knee and low back pain, falls, and health-related quality of life among Japanese older adults. A cross-sectional survey targeted 3,000 people. The response rate was 52% and 208 respondents did not meet the inclusion criteria. Therefore, 1,351 individuals were analyzed. Muscle-strengthening activity (exercise using equipment and body weight, lifestyle activities), knee and low back pain, falls over the past year, health-related quality of life (SF-8), and potential confounders were assessed. Individuals engaging in exercise using body weight and lifestyle activity (≥ 2 days/week) were more likely to have knee pain. Engaging in exercise using equipment and body weight was associated with higher scores of general health. These results indicate that exercise using equipment and body weight might have a positive effect on health-related quality of life, but muscle-strengthening activities are associated with knee pain in older people.
Removing Barriers to Athlete Performance Enhancement: A Hermeneutic Case Study of Observed and Experiential Integration
Authors: Wall Jessie M. , Kwee Janelle L. , McDonald Marvin J. , Bradshaw Richard A.
Published: December 2014

This study was the first to explore the treatment effects of observed and experiential integration (OEI) therapy for the salient psychological barriers to performance experienced by athletes. The hermeneutic single case efficacy design was used to explore the relationship between OEI therapy and athlete psychological functioning. The participant was a student-athlete who met the criteria for the performance dysfunction (multilevel classification system of Sport psychology) category, which indicates that subclinical issues were present. After five phases of data collection, a rich case record was compiled and referenced to develop skeptic and affirmative briefs and corresponding rebuttals by two research teams of three experts (OEI clinician, non-OEI clinician, and sport expert). Three independent judges adjudicated the cases and unanimously concluded that the client changed considerably to substantially and that OEI, the therapeutic relationship, and client expectancy were active variables in the change process.
Unprovoked deep venous thrombosis in a young adult associated with membranous obstruction of inferior vena cava
Authors: Epperla Narendranath , Usoltseva Natalia
Published: December 2014

Unprovoked deep venous thrombosis (DVT) in young adults is an unusual phenomenon, but it is associated with significant morbidity. Developmental anomalies of the inferior vena cava (IVC) should be considered as a possible aetiological factor, and appropriate investigations should be performed to determine the conclusive diagnosis and necessary treatment plan. We report a case of spontaneous thrombosis of the IVC and bilateral iliac venous system in a young man, associated with membranous obstruction of the IVC. He was diagnosed using several different investigational techniques, and successfully treated with mechanical thrombectomy, thrombolysis therapy and anticoagulation.
Late-onset congenital lateral dermal sinus tract
Authors: Nishimon Mari , Shimizu Yusuke , Ueno Mari , Iwanami Akio
Published: December 2014

Cases of laterally located, congenital dermal sinus tracts are extremely rare, with only six having been reported to date. We describe a case of a 14-year-old girl who developed symptoms of this type of sinus tract at an age that was considerably older than is usually reported. At the age of 12 years, the patient exhibited a purulent discharge from a pit on the right buttock. MRI indicated the presence of two tracts running from the right buttock skin to a cystic lesion that had formed on the right ala of the sacral spine. The lesion was surgically resected and successfully reconstructed using a partial iliocostalis lumborum muscle flap, without any functional morbidity. From our experience, such flaps appear to be appropriate treatment choices for lateral congenital dermal sinus tracts that develop late and result in large defects.
Absence of left circumflex with superdominant right coronary artery
Authors: Quijada-Fumero Alejandro , Pimienta-González Raquel , Rodriguez-Esteban Marcos
Published: December 2014

Congenital anomalies of coronary arteries are a group of diseases that are infrequently found. Their prevalence has been reported from 0.6% to 1.3%. Most clinical manifestations are benign and asymptomatic. Congenital absence of the left circumflex artery is a very rare congenital anomaly of the coronary circulation, and only a few cases have been reported in the literature. We report a case of a 51-year-old man who underwent a cardiac catheterisation. Coronary angiography showed a left anterior descending coronary artery with no circumflex and a dominant right coronary artery.
Rectal ulcer associated with SpaceOAR hydrogel insertion during prostate brachytherapy
Authors: Teh Amy Y M , Ko Hung-Ta , Barr Gavin , Woo Henry H
Published: December 2014

We present a case of rectal ulceration associated with SpaceOAR hydrogel insertion during low-dose-rate (LDR) brachytherapy in a patient with prostate cancer.
Postsurgical large adrenal cyst recurrence: treatment by means of percutaneous alcohol ablation
Authors: Hatzidakis Adam , Kozana Androniki , Petrakis Ioannis , Mamoulakis Charalampos
Published: December 2014

We describe a case of a 28-year-old man who presented with symptomatic, right-sided, large adrenal cyst recurrence 9 months after laparoscopic decortication. Final treatment was achieved by means of percutaneous aspiration and ethanol ablation. On 6-month follow-up the patient was asymptomatic and the cyst remained minimised. In our opinion, percutaneous treatment with alcohol ablation of primary benign symptomatic or recurrent uncomplicated adrenal cysts should be considered as an effective alternative method when patients are frail or surgery fails to resolve the problem.
A finding with a diagnosis: I just can't put my finger on it
Authors: Lambe Gerard , Le Patricia , Clay Timothy D
Published: December 2014

A 72-year-old man with metastatic squamous cell carcinoma of the lung presents with new lesions in the distal phalanx of right fifth finger (painful) and left great toe (painless due to long-standing peripheral neuropathy). Initially a complication of cytotoxic chemotherapy is considered and a dermatological opinion is requested. Enlargement of the lesions over the space of a week leads to plain X-ray, with findings of destruction of the distal phalanx of the involved digits confirming metastatic disease. Palliative radiotherapy is administered to decrease pain and reduce the likelihood of cutaneous and infectious complications. The patient died from systemic disease progression soon after finishing his radiotherapy. Digital metastasis (acrometastasis) should be considered by clinicians in the workup of patients with persistent digital symptoms, particularly in those with known cancer or those at high risk of cancer.
Functional role of myocardial electrical remodeling in diabetic rabbits
Authors: Ovechkin Alexey O. , Vaykshnorayte Marina A. , Sedova Ksenia , Shumikhin Konstantin V. , Arteyeva Natalia V. , Azarov Jan E.
Published: December 2014

The objective of the study was to investigate the role of electrical remodeling of the ventricular myocardium in hemodynamic impairment and the development of arrhythmogenic substrate. Experiments were conducted with 11 healthy and 12 diabetic (alloxan model, 4 weeks) rabbits. Left ventricular pressure was monitored and unipolar electrograms were recorded from 64 epicardial leads. Aortic banding was used to provoke arrhythmia. The diabetic rabbits had prolonged QTc, with activation–recovery intervals (surrogates for repolarization durations) being relatively short on the left ventricular base and long on the anterior apical portions of both ventricles (P < 0.05). In the diabetic rabbits, a negative correlation (–0.726 to –0.817) was observed between dP/dtmax, dP/dtmin, and repolarization dispersions. Under conditions of systolic overload (5 min), tachyarrhythmias were equally rare and the QTc and activation–recovery intervals were shortened in both groups (P < 0.05), whereas QRS was prolonged in the diabetic rabbits only. The repolarization shortening was more pronounced on the apex, which led to the development of apicobasal and interventricular end of repolarization gradients in the healthy animals, and to the flattening of the repolarization profile in the diabetic group. Thus, the diabetes-related pattern of ventricular repolarization was associated with inotropic and lusitropic impairment of the cardiac pump function.
Tunable Low Power UWB Transmitter for WBAN Application
Authors: Kumar V. Vinod , Meenakshi M.
Published: December 2014

This paper presents the design and simulation results for a Federal Communication Committee (FCC) complaint current starved delay line based Ultra Wide Band (UWB) Gaussian pulse transmitter, which is designed for operating in the 3.1–10.6 GHz range. The wavelet is a mono cycle Gaussian impulse wave, which is practically well suited for low cost, low power, low data rate wireless data transfer such as in wireless body area network (WBAN) applications. The transmitter operating frequency and bandwidth (BW) is controlled using a dc voltage provided at the input stage of a voltage controlled delay line (VCDL) and this aspect can be exploited for increasing the communication coverage area without compromising on the power consumption. A Gaussian wave shaping is performed for FCC compliance and the simulation has been carried out with 130 nm technology. The simulation of our design suggests an average dynamic power consumption of 1.11 mw for an energy efficiency of 14.2 pJ/pulse. The proposed IR-UWB transmitter design though a bit inferior in terms of the power efficiency, can claim superior performance with respect to tuning the BW, which is very relevant in a cognitive wireless networking scenario with other interfering signals.
Cosmological evolution with interaction between dark energy and dark matter
Authors: Bolotin Yuri L. , Kostenko Alexander , Lemets Oleg A. , Yerokhin Danylo A.
Published: December 2014

In this review we consider in detail different theoretical topics associated with interaction in the dark sector. We study linear and nonlinear interactions which depend on the dark matter and dark energy densities. We consider a number of different models (including the holographic dark energy and dark energy in a fractal universe), with interacting dark energy and dark matter, have done a thorough analysis of these models. The main task of this review was not only to give an idea about the modern set of different models of dark energy, but to show how much can be diverse dynamics of the universe in these models. We find that the dynamics of a universe that contains interaction in the dark sector can differ significantly from the Standard Cosmological Model.
Managing Knowledge and Information by Students
Authors: Świgoń Marzena , Weber Karsten
Published: December 2014

The concept of Personal Knowledge and Information Management (PKIM) is based, among others, on two theories: Personal Information Management (PTM) and Personal Knowledge Management (PKM), which hitherto were both subjects of separate studies. Moreover, the concept of PKIM is related to IL, which is a concept of information skills and competences of individuals — a person who manages knowledge has to be information literate. Some of the empirical studies results in the field of PKIM, started in Poland and recently continued in Germany, are presented. As the research method an unstructured questionnaire with open questions was used.

Given the results of the survey as well as taking into account the subject literature, the concepts of PIM, PKM, and Information Literacy (IL) seem to be compatible and connected with each other. Our respondents perceive Knowledge and Information as well as knowledge management (KM) and information management (IM) in the context of learning and studying as integrated areas of interests. Although they do see differences between them, interconnections and relations seem more important. Furthermore, KM and IM are recognized as tools of coping with information overload. All aspects that have repercussions on KM and IM are related to three categories: personal characteristics, environment (macro and micro environment), and knowledge and information sources.
Porphyrin nanorods-polymer composites for solar radiation harvesting applications
Authors: Mongwaketsi Nametso P. , Kotsedi Lebogang , Nuru Zebib Y. , Sparrow Raymond , Garab Gyozo , Maaza Malik
Published: December 2014

The interest in exploring porphyrin-based nanostructures for artificial solar radiation harvesting stems from their structural similarity to chlorophylls. In nature, the precise organization and orientation of the chlorophylls result in efficient absorption of light energy. Inspired by these naturally occurring architectures relevant optical studies including the dynamics of intermolecular and intra-molecular processes of the porphyrin nanorods were investigated. The design of artificial light harvesting systems requires several key factors, such as absorption in the UV-visible and near-infrared wavelengths, energy transfer ability and the selection of light absorbing pigments. Another key factor is the organizational structure through which the components will interact. We attempted to accomplish this by incorporating porphyrin nanorods into polymer matrices and this will also aid in achieving an arrangement where they can be directly used as devices. The nanorods were embedded in a polymeric matrix, using latex technology and electrospinning which gave the possibility of investigating the orientation of nanorods in the polymer. Spectroscopic and microscopic studies were conducted to investigate the optical and morphological properties of the porphyrin nanorods-polymer composites for applications in artificial solar radiation harvesting systems.
A novel terbium-cobalt tetra(4-sulfonatophenyl)porphyrin: Synthesis, structure and photophysical and electrochemical properties
Authors: Chen Wen-Tong , Huang Jian-Gen , Luo Qiu-Yan , Xu Ya-Ping , Fu Hong-Ru
Published: December 2014

A novel terbium-cobalt porphyrin {[ Tb ( H 2 O )3][ Co ( TPPS )]}n•n H 3 O (1) (TPPS = tetra(4-sulfonatophenyl)porphyrin) has been synthesized via a hydrothermal reaction and structurally characterized by X-ray single crystal diffraction. Compound 1 is characterized by a three-dimensional (3-D) porous open framework, which is originated from the Co ( TPPS ) moieties interconnected by the terbium ions. The fluorescence study shows that compound 1 displays an emission band in the blue region. Nanosecond transient spectra reveals that the fluorescence lifetime is 1.14 ms. The cyclic voltammetry (CV) and differential pulse voltammetry (DPV) experiments discovers one reversible wave with E1/2 = -0.80 V .
Cooperative Multi-Vehicle Search and Coverage Problem in an Uncertain Environment
Authors: Sharifi Farid , Mirzaei Mostafa , Zhang Youmin , Gordon Brandon W.
Published: December 2014

A distributed approach is proposed in this paper to address a cooperative multi-vehicle search and coverage problem in an uncertain environment such as forest fires monitoring and detection. Two different types of vehicles are used for search and coverage tasks: search and service vehicles. The search vehicles have a priori probability maps of targets in the environment. These vehicles update the probability maps based on their sensors measurements during the search mission. The search vehicles use a limited look-ahead dynamic programming algorithm to find their own path individually while their objective is to maximize the amount of information gathered by the whole team. The task of the service vehicles is to optimally spread out over the environment to cover the interested area for a mission. A Voronoi-based coverage control strategy is proposed to modify the configuration of service vehicles in such a way that a prescribed coverage cost function is minimized using the updated probability maps which are provided by the search vehicles. The improved performance of the proposed approach compared to conventional coverage methods is demonstrated by numerical simulation and experimental results.
CDS pricing with long memory via fractional Lévy processes
Authors: Fink Holger , Scherr Christian
Published: December 2014

In this paper, we consider spread rates of credit default swaps (CDSs) in a long memory fractional Lévy setting, i.e. where interest and hazard rates are driven by processes whose autocovariance functions decrease very slowly over time. Empirically, this property can be found in many variables like interest and hazard rates, but the usually applied Markovian models are unable to reflect this. Using earlier results on conditional distributions of fractional Lévy processes, we carry out an extensive analysis of parameter sensitivities useful for researchers and practitioners alike and derive an analytical pricing formula for CDS contracts. A first empirical application is provided as well.
Accounting for earnings announcements in the pricing of equity options
Authors: Leung Tim , Santoli Marco
Published: December 2014

We study an option pricing framework that accounts for the price impact of an earnings announcement (EA), and analyze the behavior of the implied volatility surface prior to the event. On the announcement date, we incorporate a random jump to the stock price to represent the shock due to earnings. We consider different distributions of the scheduled earnings jump as well as different underlying stock price dynamics before and after the EA date. Our main contributions include analytical option pricing formulas when the underlying stock price follows the Kou model along with a double-exponential or Gaussian EA jump on the announcement date. Furthermore, we derive analytic bounds and asymptotics for the pre-EA implied volatility under various models. The calibration results demonstrate adequate fit of the entire implied volatility surface prior to an announcement. We also compare the risk-neutral distribution of the EA jump to its historical distribution. Finally, we discuss the valuation and exercise strategy of pre-EA American options, and illustrate an analytical approximation and numerical results.
Adaptive Gesture Recognition with Variation Estimation for Interactive Systems
Authors: Caramiaux Baptiste , Montecchio Nicola , Tanaka Atau , Bevilacqua Frédéric
Published: December 2014

This article presents a gesture recognition/adaptation system for human--computer interaction applications that goes beyond activity classification and that, as a complement to gesture labeling, characterizes the movement execution. We describe a template-based recognition method that simultaneously aligns the input gesture to the templates using a Sequential Monte Carlo inference technique. Contrary to standard template-based methods based on dynamic programming, such as Dynamic Time Warping, the algorithm has an adaptation process that tracks gesture variation in real time. The method continuously updates, during execution of the gesture, the estimated parameters and recognition results, which offers key advantages for continuous human--machine interaction. The technique is evaluated in several different ways: Recognition and early recognition are evaluated on 2D onscreen pen gestures; adaptation is assessed on synthetic data; and both early recognition and adaptation are evaluated in a user study involving 3D free-space gestures. The method is robust to noise, and successfully adapts to parameter variation. Moreover, it performs recognition as well as or better than nonadapting offline template-based methods.
Affectionate Interaction with a Small Humanoid Robot Capable of Recognizing Social Touch Behavior
Authors: Cooney Martin , Nishio Shuichi , Ishiguro Hiroshi
Published: December 2014

Activity recognition, involving a capability to recognize people's behavior and its underlying significance, will play a crucial role in facilitating the integration of interactive robotic artifacts into everyday human environments. In particular, social intelligence in recognizing affectionate behavior will offer value by allowing companion robots to bond meaningfully with interacting persons. The current article addresses the issue of designing an affectionate haptic interaction between a person and a companion robot by exploring how a small humanoid robot can behave to elicit affection while recognizing touches. We report on an experiment conducted to gain insight into how people perceive three fundamental interactive strategies in which a robot is either always highly affectionate, appropriately affectionate, or superficially unaffectionate (emphasizing positivity, contingency, and challenge, respectively). Results provide insight into the structure of affectionate interaction between humans and humanoid robots—underlining the importance of an interaction design expressing sincere liking, stability and variation—and suggest the usefulness of novel modalities such as warmth and cold.
Property-Driven Design for Robot Swarms
Authors: Brambilla Manuele , Brutschy Arne , Dorigo Marco , Birattari Mauro
Published: December 2014

In this article, we present property-driven design, a novel top-down design method for robot swarms based on prescriptive modeling and model checking. Traditionally, robot swarms have been developed using a code-and-fix approach: in a bottom-up iterative process, the developer tests and improves the individual behaviors of the robots until the desired collective behavior is obtained. The code-and-fix approach is unstructured, and the quality of the obtained swarm depends completely on the expertise and ingenuity of the developer who has little scientific or technical support in his activity. Property-driven design aims at providing such scientific and technical support, with many advantages compared to the traditional unstructured approach. Property-driven design is composed of four phases: first, the developer formally specifies the requirements of the robot swarm by stating its desired properties; second, the developer creates a prescriptive model of the swarm and uses model checking to verify that this prescriptive model satisfies the desired properties; third, using the prescriptive model as a blueprint, the developer implements a simulated version of the desired robot swarm and validates the prescriptive model developed in the previous step; fourth, the developer implements the desired robot swarm and validates the previous steps. We demonstrate property-driven design using two case studies: aggregation and foraging.
Haptic 3D Surface Representation of Table-Based Data for People With Visual Impairments
Authors: Braier Jonas , Lattenkamp Katharina , Räthel Benjamin , Schering Sandra , Wojatzki Michael , Weyers Benjamin
Published: December 2014

The UN Convention on the Rights of Persons with Disabilities Article 24 states that “States Parties shall ensure inclusive education at all levels of education and life long learning.” This article focuses on the inclusion of people with visual impairments in learning processes including complex table-based data. Gaining insight into and understanding of complex data is a highly demanding task for people with visual impairments. Especially in the case of table-based data, the classic approaches of braille-based output devices and printing concepts are limited. Haptic perception requires sequential information processing rather than the parallel processing used by the visual system, which hinders haptic perception to gather a fast overview of and deeper insight into the data. Nevertheless, neuroscientific research has identified great dependencies between haptic perception and the cognitive processing of visual sensing. Based on these findings, we developed a haptic 3D surface representation of classic diagrams and charts, such as bar graphs and pie charts. In a qualitative evaluation study, we identified certain advantages of our relief-type 3D chart approach. Finally, we present an education model for German schools that includes a 3D printing approach to help integrate students with visual impairments.
Accessing Peer Social Interaction
Authors: Tartaro Andrea , Cassell Justine , Ratz Corina , Lira Jennifer , Nanclares-Nogués Valeria
Published: December 2014

Autism spectrum and related communication and social disorders can severely affect some children's ability to engage in peer social interaction. In this article, we describe and evaluate an Authorable Virtual Peer (AVP), technology designed to help children access peer interactions by supporting them in developing critical social skills. Children interact with the AVP in three ways: (1) engaging in face-to-face interaction with a life-sized, computer-animated child; (2) creating new social behaviors for the AVP; and (3) controlling the AVP using a graphical user interface to select appropriate responses while the AVP interacts with another person. Our evaluation suggests that when an AVP is used as an activity during a social group intervention, a common intervention approach used with children with social and communication difficulties, that children's use of specific social behaviors critical to successful social interaction increases during role-play of common social situations with another child.
T-Cell Cytokine Gene Polymorphisms and Vitamin D Pathway Gene Polymorphisms in End-Stage Renal Disease due to Type 2 Diabetes Mellitus Nephropathy: Comparisons with Health Status and Other Main Causes of End-Stage Renal Disease
Authors: Grzegorzewska Alicja E. , Ostromecki Grzegorz , Zielińska Paulina , Mostowska Adrianna , Jagodziński Paweł P.
Published: December 2014

Background. T-cell cytokine gene polymorphisms and vitamin D pathway gene polymorphisms were evaluated as possibly associated with end-stage renal disease (ESRD) resulting from type 2 diabetes mellitus (DM) nephropathy.Methods. Studies were conducted among hemodialysis (HD) patients with ESRD due to type 2 DM nephropathy, chronic glomerulonephritis, chronic infective tubulointerstitial nephritis, and hypertensive nephropathy as well as in healthy subjects. A frequency distribution of T-cell-related interleukin (IL) genes (IL18rs360719,IL12Ars568408,IL12Brs3212227,IL4Rrs1805015,IL13rs20541,IL28Brs8099917,IL28B, and rs12979860) and vitamin D pathway genes (GC genes: rs2298849, rs7041, and rs1155563; VDR genes: rs2228570, rs1544410; and RXRA genes: rs10776909, rs10881578, and rs749759) was compared between groups.Results. No significant differences in a frequency distribution of tested polymorphisms were shown between type 2 DM nephropathy patients and controls. A difference was found inIL18rs360719 polymorphic distribution between the former group and chronic infective tubulointerstitial nephritic patients (Ptrend=0.033), which also differed in this polymorphism from controls (Ptrend=0.005).Conclusion. T-cell cytokine and vitamin D pathway gene polymorphisms are not associated with ESRD due to type 2 DM nephropathy in Polish HD patients.IL18rs360719 is probably associated with the pathogenesis of chronic infective tubulointerstitial nephritis.
Bladder Perforation Secondary to Primary Systemic Amyloidosis
Authors: Dru Christopher J. , Feng Tom S. , Kim Howard H.
Published: December 2014

Amyloidosis is a disorder of protein folding characterized by extracellular aggregation and deposition of amyloid protein fibrils. Light-chain amyloidosis, also known as primary systemic amyloidosis, is the most common form of the disease. We present a case of an 84-year-old male with a history of systemic primary amyloidosis causing genitourinary, cardiac, and autonomic dysfunction who presented with hematuria and hypotension secondary to bladder perforation. He underwent open repair of a large extraperitoneal bladder defect. He ultimately died as a result of medical complications from his disease.
Outcomes and Complications of the Midline Anterior Approach 3 Years after Lumbar Spine Surgery
Authors: Fischer Charla R. , Braaksma Brian , Peters Austin , Weinreb Jeffrey H. , Nalbandian Matthew , Spivak Jeffrey M. , Petrizzo Anthony
Published: December 2014

Objective. The purpose of this study was to evaluate a new questionnaire to assess outcomes related to the midline anterior lumbar approach and to identify risk factors for negative patient responses.Methods. A retrospective review of 58 patients who underwent anterior lumbar surgery at a single institution for either degenerative disc disease or spondylolisthesis in 2009 was performed. The outcome measures included our newly developed Anterior Lumbar Surgery Questionnaire (ALSQ), ODI, and EQ-5D.Results. There were 58 patients available for followup, 27 women and 31 men. The average age at surgery was 50.8 years, with an average followup of 2.92 years. The average change in ODI was 34.94 (22.7) and EQ-5D was 0.28 (0.29). The rate of complications with the anterior approach was 10.3% and there was one male patient (3.2%) with retrograde ejaculation. Determination of the effectiveness of the new ALSQ revealed that it significantly correlated to the EQ-5D and ODI(P<0.05). Smoking was associated with a negative response on thirteen questions. BMP use was not associated with a negative response on any sexual function questions.Conclusions. Our new Anterior Lumbar Surgery Questionnaire determines patient perceived complications related to the midline anterior lumbar surgical approach.
On Parametric Gevrey Asymptotics for Some Cauchy Problems in Quasiperiodic Function Spaces
Authors: Lastra A. , Malek S.
Published: December 2014

We investigate Gevrey asymptotics for solutions to nonlinear parameter depending Cauchy problems with 2π-periodic coefficients, for initial data living in a space of quasiperiodic functions. By means of the Borel-Laplace summation procedure, we construct sectorial holomorphic solutions which are shown to share the same formal power series as asymptotic expansion in the perturbation parameter. We observe a small divisor phenomenon which emerges from the quasiperiodic nature of the solutions space and which is the origin of the Gevrey type divergence of this formal series. Our result rests on the classical Ramis-Sibuya theorem which asks to prove that the difference of any two neighboring constructed solutions satisfies some exponential decay. This is done by an asymptotic study of a Dirichlet-like series whose exponents are positive real numbers which accumulate to the origin.
Ciprofloxacin Release Using Natural Rubber Latex Membranes as Carrier
Authors: Dias Murbach Heitor , Jaques Ogawa Guilherme , Azevedo Borges Felipe , Romeiro Miranda Matheus Carlos , Lopes Rute , Roberto de Barros Natan , Guedes Mazalli Alexandre Vinicius , Gonçalves da Silva Rosângela , Ferreira Cinman José Luiz , de Camargo Drago Bruno , Donizetti Herculano Rondinelli
Published: December 2014

Natural rubber latex (NRL) fromHevea brasiliensisis easily manipulated, low cost, is of can stimulate natural angiogenesis and cellular adhesion, is a biocompatible, material and presents high mechanical resistance. Ciprofloxacin (CIP) is a synthetic antibiotic (fluoroquinolone) used in the treatment of infection at external fixation screws sites and remote infections, and this use is increasingly frequent in medical practice. The aim of this study was to develop a novel sustained delivery system for CIP based on NRL membranes and to study its delivery system behavior. CIP was found to be adsorbed on the NRL membrane, according to results of energy dispersive X-ray spectroscopy. Results show that the membrane can release CIP for up to 59.08% in 312 hours and the mechanism is due to super case II (non-Fickian). The kinetics of the drug release could be fitted with double exponential function X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy shows some interaction by hydrogen bound, which influences its mechanical behavior.
Correlation between Serum RANTES Levels and the Severity of Parkinson’s Disease
Authors: Tang Peng , Chong Li , Li Xiaoqing , Liu Yue , Liu Peng , Hou Chen , Li Rui
Published: December 2014

Inflammatory mediators may reflect a role of systemic inflammation in the neurodegenerative process of Parkinson’s disease (PD). Interleukin-6 (IL-6) and chemokine ligand 5 (CCL5), also known as RANTES (regulated on activation, normal T cell expressed and secreted), have been implicated in neurodegenerative diseases including PD. Serum levels of RANTES and IL-6 of 78 consecutive PD patients and age-matched 80 controls were measured. Patients with PD had higher RANTES and IL-6 levels compared with the controls. We found that serum RANTES levels strongly correlated with Hoehn-Yahr score and disease duration in PD patients. This study indicated that patients with PD have an on-going systemic inflammatory profile where the elevated peripheral production of RANTES may play a role in the neurodegenerative process.