Overlay Model Research Articles

A Scheme to Address Routers in MIMO Triangular Wireless Overlay Mesh

A scheme to address router nodes is given for wireless Mesh Networks (WMN) with multiple input multiple output (MIMO) character. Both the wireless transceiver number of a node and geographical topology mesh contribute to wireless overlay model by placing link into different channel planes edge in case of interference. The triangular mesh is an important overlay topology for wireless networks. The router node addressing scheme keeps its instinct symmetric property. Several general cases over the addressing scheme are also discussed for the shortest routing path and the node coordination itself. The interference relation is abstracted into set models. Furthermore, the length of the shortest path is also given by a formula with the source node and destination node addresses. A general conclusion on relation of node address and hop count is also given.

Framework for exploring the interaction between design rules and overlay control

Overlay control is becoming increasingly more important with the scaling of technology. It has become even more critical and more challenging with the move toward multiple-patterning lithography, where overlay translates into CD variability. Design rules and overlay have strong interaction and can have a considerable impact on the design area, yield, and performance. We study this interaction and evaluate the overall design impact of rules, overlay characteristics, and overlay control options. For this purpose, we developed a model for yield loss from overlay that considers overlay residue after correction and the breakdown between field-to-field and within-field overlay; the model is then incorporated into a general design-rule evaluation framework to study the overlay/design interaction. The framework can be employed to optimize design rules and more accurately project overlay-control requirements of the manufacturing process. The framework is used to explore the design impact of litho-etch litho-etch double-patterning rules and poly line-end extension rule defined between poly and active layer for different overlay characteristics (i.e., within-field versus field-to-field overlay) and different overlay models at the 14-nm node. Interesting conclusions can be drawn from our results. For example, one result shows that increasing the minimum mask-overlap length by 1 nm would allow the use of a third-order wafer/sixth-order field-level overlay model instead of a sixth-order wafer/sixth-order field-level model with negligible impact on design.

Polypropylene surgical mesh coated with extracellular matrix mitigates the host foreign body response

Surgical mesh devices composed of synthetic materials are commonly used for ventral hernia repair. These materials provide robust mechanical strength and are quickly incorporated into host tissue; factors that contribute to reduced hernia recurrence rates. However, such mesh devices cause a foreign body response with the associated complications of fibrosis and patient discomfort. In contrast, surgical mesh devices composed of naturally occurring extracellular matrix (ECM) are associated with constructive tissue remodeling, but lack the mechanical strength of synthetic materials. A method for applying a porcine dermal ECM hydrogel coating to a polypropylene mesh is described herein with the associated effects upon the host tissue response and biaxial mechanical behavior. Uncoated and ECM coated heavy-weight BARD™ Mesh were compared to the light-weight ULTRAPRO™ and BARD™ Soft Mesh devices in a rat partial thickness abdominal defect overlay model. The ECM coated mesh attenuated the pro-inflammatory response compared to all other devices, with a reduced cell accumulation and fewer foreign body giant cells. The ECM coating degraded by 35 days, and was replaced with loose connective tissue compared to the dense collagenous tissue associated with the uncoated polypropylene mesh device. Biaxial mechanical characterization showed that all of the mesh devices were of similar isotropic stiffness. Upon explanation, the light-weight mesh devices were more compliant than the coated or uncoated heavy-weight devices. This study shows that an ECM coating alters the default host response to a polypropylene mesh, but not the mechanical properties in an acute in vivo abdominal repair model.

An Efficient P2P Overlay Network Model Based on Clustering

The P2P system was build with the topological structure of the network at the application layer, network topological structure for an P2P system has a very important significance. There is currently a wide range of different topology structure of P2P network, HCPON uses two-level clustering structure, based on HCPON, we propose an efficient overlay network model based on clustering (PONM), it solves the problem that the super node only uses a single backup node as a redundant backup leading system robustness improvement is limited in unstructured P2P system. The model through a directory server to manage all nodes on the network, The results of the simulation demonstrates that,compared with HCPON, PONM has a relatively stable path stretching rate and lower average link pressure, can meet the requirements of Large-Scale P2P streaming media service needs.

PeRSIVA: An empirical evaluation method of a student model of an intelligent e-learning environment for computer programming

In this paper an evaluation method for assessing the effectiveness, accuracy and validity of a student model was presented. Our method is called PeRSIVA and is a combination of the well-known evaluation method of Kirkpatrick and the layered evaluation framework. These well-known and commonly used evaluation techniques have been selected in order to design an accurate and correct evaluation methodology, since there are no clear guidelines in the literature for the evaluation of the student model of an adaptive tutoring system. Furthermore, PeRSIVA method was used to evaluate the hybrid student model, which combines an overlay model with stereotypes and fuzzy logic techniques, of an e-learning system. Particularly, PeRSIVA assesses the results of student modeling in students' satisfaction, performance, progress, behavior and state, as well as the validity of the conclusions drawn by the student model and the validity of the adaptation decision making. The e-learning system was used by the students of a postgraduate program in the field of informatics in the University of Piraeus and the evaluation results demonstrated learning improvements in students and adaptation success to students' needs.

Hybrid Optical Switching for Energy-Efficiency and QoS Differentiation in Core Networks

In the future, the Internet may ultimately be constrained by energy consumption and the capability to provide quality of service (QoS). As regards the Internet core, hybrid optical switching (HOS) is promising to provide service differentiation and reduced energy consumption in respect to current electronic switching solutions. In this paper we present a novel hybrid HOS network architecture that efficiently integrates the optical packet, burst, and circuit switching on the same network. The proposed HOS network envisages the use of two parallel switches, a slow optical switch for the transmission of circuits and long bursts, and a fast switch for the transmission of packets and short bursts. The most appropriate switching method is selected for the traffic generated by different applications and the less power consuming elements are utilized for transmission, ensuring flexibility, QoS differentiation, and low energy consumption. The HOS network is organized in an overlay model with the HOS control layer performing routing, signaling, and link management, and with the HOS forwarding layer managing the reservation of resources and data scheduling. Performance and energy efficiency of the analyzed network are assessed by means of a combined analytical and simulation approach.

Overlay cognitive radio OFDM system for 4G cellular networks

In this study, we integrate overlay cognitive radio technology into 4G cellular networks for the sharing of TV spectrum. On one hand, OFDM is a promising technique for high-speed data transmission over multipath fading channels and has been considered to be the best candidate for 4G mobile networks. On another hand, the overlay cognitive radio model makes it possible to have two concurrent transmissions in a given interference region, where conventionally only one communication takes place at a given time. We investigate different service provision scenarios and propose both time domain and frequency domain overlay cognitive radio OFDM systems for next generation cellular networks. Numerical results show our proposed schemes can achieve satisfying performance in different use cases.

EXPERIMENTAL CHARACTERIZATION AND MODELLING OF LARGE-STRAIN VISCOELASTIC BEHAVIOR OF A THERMOPLASTIC POLYURETHANE ELASTOMER

ABSTRACTThermoplastic polyurethane elastomers (TPUs) are a kind of elastomer that can be processed as thermoplastics. These elastomers exhibit a highly nonlinear behavior characterized by hyper-elastic deformability. Furthermore, the mechanical behavior of these elastomers is time-dependent, that is, they exhibit a viscoelastic behavior. We describe the material response of a TPU under moderate strains (ɛ < 1) by using an overlay visco-hyperelastic model assuming separation of time dependence from nonlinear stress–strain behavior. To achieve this goal, cyclic loading–unloading experimental tests are carried out for two homogeneous deformation states, uniaxial tension and pure shear, and the strain–stress data are then analyzed to fit a hyperelastic model. Conversely, a viscoelastic model is obtained from relaxation tests. Finally, the visco-hyperelastic model is implemented in a finite element calculation tool (ABAQUS), and the numerical results show a reasonable correlation with experimental data. As a result, a overlay visco-hyperelastic model depending on maximum strain is proposed.

Surgical navigation with a head-mounted tracking system and display.

We present the design of a self-contained head-mounted surgical navigation system, which consists of an optical tracking system and an optical see-through head-mounted display (HMD). While the current prototype is bulky, we envision a more compact solution via the eventual integration of the tracking camera(s) into the HMD goggles. Rather than attempting to accurately overlay preoperative models onto the field of view, we adopted a simpler approach of displaying a small "picture-in-picture" virtual view in the HMD. We believe this approach will provide suitable assistance for some image-guided procedures, such as tumor resection, while improving the ergonomics by reducing the need for the surgeon to look away from the patient to view an external monitor. We report the results of initial experiments performed with this system, while preparing for a more clinically realistic study.

Toward an Adaptive Learning System Framework: Using Bayesian Network to Manage Learner Model

This paper represents a new approach to manage learner modeling in an adaptive learning system framework. It considers developing the basic components of an adaptive learning system such as the learner model, the course content model and the adaptation engine. We use the overlay model and Bayesian network to evaluate learnersâ?? knowledge. In addition, we also propose a new content modeling method as well as adaptation engine to generate adaptive course based on learnerâ??s knowledge. Based on this approach, we developed an adaptive learning system named is ACGS-II, that teaches students how to design an Entity Relationship model in a database system course. Empirical testing results for students who used the application indicate that our proposed model is very helpful as guidelines to develop adaptive learning system to meet learnersâ?? demands.

RNA-Seq of Human Breast Ductal Carcinoma In Situ Models Reveals Aldehyde Dehydrogenase Isoform 5A1 as a Novel Potential Target

Breast ductal carcinoma in situ (DCIS) is being found in great numbers of women due to the widespread use of mammography. To increase knowledge of DCIS, we determined the expression changes that are common among three DCIS models (MCF10.DCIS, SUM102 and SUM225) compared to the MCF10A model of non-tumorigenic mammary epithelial cells in three dimensional (3D) overlay culture with reconstituted basement membrane (rBM). Extracted mRNA was subjected to 76 cycles of deep sequencing (RNA-Seq) using Illumina Genome Analyzer GAIIx. Analysis of RNA-Seq results showed 295 consistently differentially expressed transcripts in the DCIS models. These differentially expressed genes encode proteins that are associated with a number of signaling pathways such as integrin, fibroblast growth factor and TGFβ signaling, show association with cell-cell signaling, cell-cell adhesion and cell proliferation, and have a notable bias toward localization in the extracellular and plasma membrane compartments. RNA-Seq data was validated by quantitative real-time PCR of selected differentially expressed genes. Aldehyde dehydrogenase 5A1 (ALDH5A1) which is an enzyme that is involved in mitochondrial glutamate metabolism, was over-expressed in all three DCIS models at both the mRNA and protein levels. Disulfiram and valproic acid are known to inhibit ALDH5A1 and are safe for chronic use in humans for other disorders. Both of these drugs significantly inhibited net proliferation of the DCIS 3D rBM overlay models, but had minimal effect on MCF10A 3D rBM overlay models. These results suggest that ALDH5A1 may play an important role in DCIS and potentially serve as a novel molecular therapeutic target.

Three-dimensional cultures modeling premalignant progression of human breast epithelial cells: role of cysteine cathepsins

The expression of the cysteine protease cathepsin B is increased in early stages of human breast cancer.To assess the potential role of cathepsin B in premalignant progression of breast epithelial cells, we employed a 3D reconstituted basement membrane overlay culture model of MCF10A human breast epithelial cells and isogenic variants that replicate the in vivo phenotypes of hyper plasia(MCF10AneoT) and atypical hyperplasia (MCF10AT1). MCF10A cells developed into polarized acinar structures with central lumens. In contrast, MCF10AneoT and MCF10AT1 cells form larger structures in which the lumens are filled with cells. CA074Me, a cell-permeable inhibitor selective for the cysteine cathepsins B and L,reduced proliferation and increased apoptosis of MCF10A, MCF10AneoT and MCF10AT1 cells in 3D culture. We detected active cysteine cathepsins in the isogenic MCF10 variants in 3D culture with GB111, a cell-permeable activity based probe, and established differential inhibition of cathepsin B in our 3D cultures. We conclude that cathepsin B promotes proliferation and premalignant progression of breast epithelial cells. These findings are consistent with studies by others showing that deletion of cathepsin B in the transgenic MMTV-PyMT mice, a murine model that is predisposed to development of mammary cancer, reduces malignant progression.

A hierarchical overlay with cluster-based reputation tree for dynamic peer-to-peer systems

Traditional peer-to-peer technologies and systems assume that people operate with desktop computers in fixed broadband networks. When people with modern mobile devices now access Internet and Web services much in the manner they used to on desktop computers, the classical peer-to-peer overlay models can be vulnerable in wireless and mobile networks. This paper proposes a hierarchical overlay architecture based on partially central and semi-structured overlay models for the deployment of peer-to-peer systems in dynamic network environments. To keep up system scalability and efficacy, this architecture design exploits peer locality and network proximity, and contends with several problems of peer churn, peer mobility, search redundancy and traffic overhead that become much stickier in dynamic network environments. This design also integrates the reputation notion to mitigate the free-riding problem in peer-to-peer systems. According to a special cluster-based reputation tree, the hierarchical overlay is adjustable to moderate unfair or imbalanced resource utilization over the system. Furthermore, the cluster hierarchy is resilient to any points of failure at peer clusters in the overlay topology. Therefore, the effort of this study achieves an efficient and robust overlay architecture in dynamic network environments. Simulation results show that the proposed architecture is not only scalable to peer population, but also sustainable to peer- and network-initiated dynamics and influences in peer-to-peer systems.

Application of Geographic Information System (GIS) in Accuracy Assessment of Existing Land Use Map a Case Study of Enugu Area, South-Eastern Nigeria

It is suspected that continuous building collapses within Enugu area is due to faulty landuse map. This work aims at employing geographic information system principles to assess the validity of the existing landuse map of Enugu area. Three landuse options were considered (Industrial, residential and waste). The study was undertaken using Arc view 3.2a academic, Excel Statistical Software and autocard software of GIS. A total of 12 landuse determinants were selected as thematic data layers and basic factors influencing the choice of industrial, residential and waste disposal landuses. Soil characteristics and geology were integrated into the thematic maps to facilitate the weighting of the basic determinants. The thematic layers were weighted on a scale of 0% - 100% and 0-2 inclusive, using the criteria obtained from field work and laboratory investigation. The thematic layers for each landuse were subjected to overlay using arc view software overlay model builder. The operation yielded three (3) different landuse maps (Industrial, residential and wasted disposal,) which were further superimposed to produce a composite landuse map useful for regional and urban planning. Correlation with existing landuse map, exposed a lot of limitations of the existing landuse map. All the residential and industrial areas of the existing landuse map fall within the low capacity areas of the present study. Areas selected as open space by the existing landuse map correspond to the areas of industrial and residential land uses of the present study. Areas limited for use by the present study due to hazards of flooding, landslide, fault and gully erosion were not considered by the existing landuse map, rather they were mapped out for industrial, residential and partly as open space. The existing landuse map has no provision for waste disposal. The present study shows that areas to the West, Southwest and Southeast are highly suitable for industrial and residential landuses. The limitations of the existing landuse map exposed by the present study must have accounted for the cases of building collapses in the area.

Study on the routing mechanisms in ip over wdm networks with overlay model.

Study on the routing mechanisms in ip over wdm networks with overlay model.

Evaluating the integration of fuzzy logic into the student model of a web-based learning environment

In this paper, we evaluate the effectiveness and accuracy of the student model of a web-based educational environment for teaching computer programming. Our student model represents the learner’s knowledge through an overlay model and uses a fuzzy logic technique in order to define and update the student’s knowledge level of each domain concept, each time that s/he interacts with the e-learning system. Evaluation of the student model of an Intelligent Tutoring System (ITS) is an aspect for which there are not clear guidelines to be provided by literature. Therefore, we choose to use two well-known evaluation methods for the evaluation of our fuzzy student model, in order to design an accurate and correct evaluation methodology. These evaluation models are: the Kirkpatrick’s model and the layered evaluation method. Our system was used by the students of a postgraduate program in the field of Informatics in the University of Piraeus, in order to learn how to program in the programming language C. The results of the evaluation were very encouraging.

Ecological suitability evaluation for urban growth boundary in red soil hilly areas based on fuzzy theory

The fuzziness exists in spatial distribution of geographic data of land suitability evaluation processes, which makes it difficult to quantify land boundaries by using traditional binary logic-based overlay model. Aiming at this limitation, an ecological suitability evaluation analysis model was presented based on fuzzy theory and a research on urban growth boundary (UGB) of the Great-Hexi Leading District (GHLD) of Changsha was conducted. With the support of GIS, RS and MATLAB, slope, elevation, vegetation, soil productivity, soil permeability, water body and land use are selected as the input of model according to the characteristic properties of soil and terrain in red soil hilly areas. The running result of this model indicates that the ratios of highly suitable land, suitable land, moderately suitable land and unsuitable land in GHLD are 18.75%, 10.31%, 64.16%, 6.78%, respectively. This result accords with spatial structure worked out by Space Development Strategy Planning of GHLD. Based on this result, several suggestions are made to guide UGB developments in future.

Abstract 2467: Acidic pericellular pH increases contribution of cathepsin B to invasiveness of a human breast carcinoma cell line

Abstract Among the non-cellular microenvironmental factors that may contribute to malignancy of solid tumors is an acidic peritumoral pH (pHe). We have shown that this induces secretion of the lysosomal cysteine protease, cathepsin B. The object of the present study was to further examine the effect of a slightly acidic pericellular pH (i.e., pHe 6.8) on degradation of collagen IV and the activity and secretion of proteolytic enzymes, in particular cathepsin B. For these studies, we used: 1) a highly malignant human breast carcinoma line, MDA-MB-231-RFP; 2) a 3D reconstituted basement membrane overlay culture model; 3) a live cell confocal microscopy assay for imaging proteolysis and detecting active cathepsin B via an activity based probe, GB123; 4) a protocol for quantification of proteolysis on a per cell basis; 5) and fluorometric real-time and plate-reader assays for measuring cathepsin B activity. The live cell proteolysis assay confirmed that degradation of collagen IV by the MDA-MB-231 cells was consistently higher at a slightly acidic pHe and was decreased by a highly selective cathepsin B inhibitor, CA074. A dramatic increase in cathepsin B secretion from MDA-MB-231 cells was observed upon exposure to an acidic pHe, as assessed by assays of conditioned media and analysis of secretion in real-time. Our results are consistent with the hypothesis by Gillies and colleagues of “acid-mediated invasion” in tumors and suggest a role for cathepsin B in promoting degradation of collagen IV and thereby tumor invasiveness in the acidic peritumoral microenvironment. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2467. doi:1538-7445.AM2012-2467

Application of X-ray Photoelectron Spectroscopic Analysis to Protein Adsorption on Materials Relevant to Biomanufacturing

X-ray photoelectron spectroscopy (XPS) has been used to analyze the adsorption of a therapeutic monoclonal antibody (mAb), rituximab, and polyclonal human IgG (hIgG) on materials relevant to biomanufacturing of protein drug products. Details of the methods used to obtain qualitative confirmation of protein adsorption, using both the nitrogen (N 1s) signal originating from mAb proteins and an iodine heteroatom label, are presented. Both rituximab and hIgG were found to adsorb to a glass vial surface, vial rubber cap liner, syringe plunger tip, cell culture flask, serological pipette, and microcentrifuge tube. There was no evidence of protein adsorption on samples of polyvinylchloride (PVC) tubing or the barrel of a syringe. Differences in XPS heteroatom peak intensities, based on whether the heteroatom label was added to the protein prior to surface adsorption or after, suggest that adsorbed rituximab on a glass vial surface is in a structural conformation that allows extensive heteroatom labeling. Using a simple uniform overlayer model, the coverage of rituximab on a glass vial surface was determined by XPS to be 3.6 mg/m(2) , a value consistent with that expected for a theoretical monolayer.

Discovery of 1,4-Disubstituted 3-Cyano-2-pyridones: A New Class of Positive Allosteric Modulators of the Metabotropic Glutamate 2 Receptor

The discovery and characterization of compound 48, a selective and in vivo active mGlu2 receptor positive allosteric modulator (PAM), are described. A key to the discovery was the rational exploration of the initial HTS hit 13 guided by an overlay model built with reported mGlu2 receptor PAM chemotypes. The initial weak in vitro activity of the hit 13 was quickly improved, although compounds still had suboptimal druglike properties. Subsequent modulation of the physicochemical properties resulted in compounds having a more balanced profile, combining good potency and in vivo pharmacokinetic properties. Final refinement by addressing cardiovascular safety liabilities led to the discovery of compound 48. Besides good potency, selectivity, and ADME properties, compound 48 displayed robust in vivo activity in a sleep-wake electroencephalogram (sw-EEG) assay consistent with mGlu2 receptor activation, in accordance with previous work from our laboratories.