Robotic clusters: Multi-robot systems as computer clusters: A topological map merging demonstration

In most multi-robot systems, an individual robot is not capable of solving computationally hard problems due to lack of high processing power. This paper introduces the novel concept of robotic clusters to empower these systems in their problem solving. A robotic cluster is a group of individual robots which are able to share their processing resources, therefore, the robots can solve difficult problems by using the processing units of other robots. The concept, requirements, characteristics and architecture of robotic clusters are explained and then the problem of “topological map merging” is considered as a case study to describe the details of the presented idea and to evaluate its functionality. Additionally, a new parallel algorithm for solving this problem is developed. The experimental results proved that the robotic clusters remarkably speedup computations in multi-robot systems. The proposed mechanism can be used in many other robotic applications and has the potential to increase the performance of multi-robot systems especially for solving problems that need high processing resources.     

A new reactor concept for combining oxidative coupling and steam re‐forming of methane: modeling and analysis

A new and very promising application of auto‐thermal reactors is the coupling of endothermic and exothermic reactions where the product of the endothermic reaction is the desired one. Therefore, in this work, a reactor in which oxidative coupling of methane (OCM) and steam re‐forming of methane (SRM) reactions take place simultaneously was modeled. The results were obtained in a wide range of different conditions such as inlet feed, inlet temperature, portions of OCM and SRM catalysts, and inlet velocity. In selection of the catalysts, more attention was drawn to prevent re‐forming of OCM products. The main parameters of each reaction under different conditions such as conversion of the feed components, products selectivity and yield, temperature in the length of reactor, and component's concentration in the reactor were considered in course of this study. The results revealed that simultaneous OCM and SRM reactions in one reactor will tend to be auto‐thermal, and the waste of energy will be reduced. The results also show that complete conversion of water and majority of methane and oxygen will decrease the amount of unwanted products at the reactor's discharge–a constraint that exists in single reactors of each reaction specially OCM. Copyright © 2011 John Wiley & Sons, Ltd.     

Visual laser ablation of the prostate for patients with acute urinary retention

Examination of the long-term relation of a single fibrinogen determination to initial and recurrent atherosclerotic cardiovascular events over 20 years of follow-up revealed a powerful and comparably independent impact on initial events in both sexes but an influence on recurrent events only in men.     

Quantum chemical studies on molecular conformations,energetic and intramolecular hydrogen bonding in ground and electronic excited state of (thioxosilyl) ethyleneselenol

In this work, a conformational analysis of (thioxosilyl) ethyleneselenol was performed using several computational methods, including density-functional theory (DFT) (B3LYP), MP2 and G2MP2. Harmonic vibrational frequencies were estimated at the same levels to confirm the nature of the stationary points found and also to account for the zero point vibrational energy correction. MES-1 and TES-1 conformers exhibit hydrogen bonding. This feature, although is not the dominant factor in the stability of conformers, appears to be of foremost importance to define the geometry of the molecule. Two intramolecular hydrogen bonds established between the polar groups were identified by the structural geometric parameters. These involved the thiol and selenol functional groups and were identified and characterized by the frequency shift in their stretching vibration modes. Furthermore, the excited-state properties of intramolecular hydrogen bonding have been investigated theoretically using the time-dependent DFT method. The influence of the solvent on the stability order of conformers and the strength of intramolecular hydrogen bonding was considered using the PCM (polarizable continuum model), SCI-PCM (self consistent isodensity-polarizable continuum model) and IEF-PCM (integral equation formalism-polarizable continuum model) methods. The “atoms in molecules” theory of Bader was used to analyze critical points and to study the nature of hydrogen bond in these systems. Natural bond orbital (NBO) analysis was also performed for better understanding the nature of intramolecular interactions. The calculated highest occupiedmolecular orbital and lowest unoccupied molecular orbital energies show that charge transfer occur within the molecule. Further verification of the obtained transition state structures was implemented via intrinsic reaction coordinate analysis. Calculations of the ¹H NMR chemical shift at the GIAO/B3LYP/6–311++G** level of theory are also presented.     

Steganalysis of images based on spatial domain and two-dimensional JPEG array

The aim of digital image steganalysis is to detect hidden information (which can be a message or an image) in a steganographic image. An ideal steganography method encrypts the information in the image such that it cannot be easily detected. Currently, a wide variety of different steganography techniques are being used; therefore, more advanced steganalysis methods are needed that can detect the steganographic images coded by different techniques. A typical steganalysis technique consists of two parts: (1) feature extraction and (2) classification. In this paper, a new steganalysis technique based on the Markov chain process is proposed. In the proposed technique, after extraction of the new features, a non-linear classifier named support vector machine is applied to classify clean and encrypted images. Analysis of variance is used to reduce the dimensions of the proposed features. The performance of the proposed technique is compared against subtractive DCT coefficient adjacency matrix (SDAM) and subtractive pixel adjacency matrix (SPAM) methods using an image database prepared by three strong steganography techniques called yet another steganographic scheme, model based, and perturbed quantization. The obtained results show that the proposed method provides better performance than SDAM and SPAM methods.     

Simplified recursive identifier for ARMA processes

Symmetrical behaviour of the covariance matrix and the positive-definite criterion are used to simplify identification of single-input/single-output systems using recursive least squares. Simulation results are obtained and these are compared with ordinary recursive least squares. The adaptive nature of the identifier is verified by varying the system parameters on convergence.     

The Tunable Porous Structure of Gelatin–Bioglass Nanocomposite Scaffolds for Bone Tissue Engineering Applications: Physicochemical,Mechanical, and In Vitro Properties

Unidirectional freeze‐casting method is used to fabricate gelatin–bioglass nanoparticles (BGNPs) scaffolds. Transmission electron microscopy (TEM) images show that sol–gel prepared BGNPs are distributed throughout the scaffold with diameters of less than 10 nm. Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetric are used to evaluate the physicochemical properties of BGNPs. Scanning electron microscopy (SEM) micrographs present an oriented porous structure and a homogeneous distribution of BGNPs in the gelatin matrix. The lamellar‐type structure indicates an improvement of mechanical strength and absorption capacity of the scaffolds. Increasing the concentration of BGNPs from 0 to 50 wt% have no noticeable effect on pore orientation, but decreases porosity and pore size distribution. Increase in BGNPs content improves the compressive strength. The absorption and biodegradation rate reduces with augmentation in BGNPs concentration. Bioactivity is evaluated through apatite formation after immersion of the nanocomposites in simulated body fluid and is verified by SEM–energy‐dispersive X‐ray spectroscopy (EDS), an element map analysis, X‐ray powder diffractometer, and FTIR spectrum. SEM images and methyl thiazolyl tetrazolium assay confirm the biocompatibility of scaffolds and the supportive behavior of nanocomposites in cellular spreading. The results show that gelatin–(30 wt%)bioglass nanocomposites have incipient physicochemical and biological properties.     

Standards, options and recommendations (SOR) for clinical care of rhabdomyosarcoma (RMS) and other soft tissue sarcoma in children. Federation of the French Cancer Centers. French Society of Pediatric Oncology

CONTEXT: The "Standards, Options and Recommendations" (SOR) project, started in 1993, is a collaboration between the Federation of the French Cancer Centres (FNCLCC), the 20 French Cancer Centres and specialists from French Public Universities, General Hospitals and Private Clinics. For pediatric issues, this project is a collaboration between the FNCLCC and the French Society of Pediatric Oncology (SFOP). The main objective is the development of clinical practice guidelines to improve the quality of health care and outcomes for cancer patients. The methodology is based on literature review and critical appraisal by a multidisciplinary group of experts, with feedback from specialists in cancer care delivery. OBJECTIVES: To develop a clinical practice guideline according to the definitions of Standards, Options and Recommendations for the clinical care of rhabdomyosarcoma and other soft tissue sarcoma in children and adolescents. METHODS: Data have been identified by literature search using Medline (1985-may 1997) and experts group personal references lists. The main criteria considered were incidence, risk factors, prognostic factors and efficacy of cancer treatment. Once the guideline was defined, the document was submitted for review to 14 national and international independent reviewers, and to the medical committees of the 20 French Cancer Centres and, in particular the 4 which have expertise in pediatric cancer management, for agreement. RESULTS: The main recommendations for rhabdomyosarcoma management are: 1/ diagnosis is based on appropriate clinical and radiological findings; 2/ pathological and immunohistochemical studies are essential to confirm the diagnosis; 3/ surgery must be performed by an experienced surgeon. Surgery and radiotherapy must be as conservative as possible; 4/ therapeutic strategies for rhabdomyosarcoma depend on location and extends and are based on chemotherapy, surgery and radiotherapy. Inclusion of patients in SFOP, SIOP and IRS clinical trials is recommended; 5/ treatment of metastatic rhabdomyosarcoma is based on intensive chemotherapy, and surgery with or without radiotherapy; 6/ the management of non-rhabdomyosarcoma is based on the likelihood of sensitivity to chemotherapy; 7/ at the present time, there are no clear data on which to base guidelines for timing and duration of follow-up studies in these conditions.     

Experimental and Numerical Crashworthiness Investigation of the Empty and Foam‐Filled Conical Tube with Shallow Spherical Caps

This paper experimentally investigates the crash responses of the empty and polyurethane foam‐filled conical tubes with shallow spherical caps under quasi‐static axial loading. To find more details about the energy absorption mechanism, finite element methods is used to simulate the crush process. In terms of finding more efficient and lighter crash absorbers particularly, the energy absorption and specific energy absorption and load ratio have been considered. The influences of the tube geometrical and material parameters such as radius of spherical region, wall thickness, length, semi‐apical angle and foam density on the energy absorption mechanism have been investigated. This study provides practical information for the use of thin‐walled tubes with shallow spherical caps as energy absorbers in aerospace applications to design reentry of sounding rocket based on foam‐filled conical tube with shallow spherical caps.