A unified approach to superresolution and multichannel blind deconvolution.

This paper presents a new approach to the blind deconvolution and superresolution problem of multiple degraded low-resolution frames of the original scene. We do not assume any prior information about the shape of degradation blurs. The proposed approach consists of building a regularized energy function and minimizing it with respect to the original image and blurs, where regularization is carried out in both the image and blur domains. The image regularization based on variational principles maintains stable performance under severe noise corruption. The blur regularization guarantees consistency of the solution by exploiting differences among the acquired low-resolution images. Several experiments on synthetic and real data illustrate the robustness and utilization of the proposed technique in real applications.     

Smoothing Streams in an In-Home Digital Network: Optimization of Bus and Buffer Usage

In an in-home digital network it may be expected that several data streams (audio, video) run simultaneously over a shared communication device, e.g., a bus. The burstiness of a data stream can be reduced by buffering data at the sending and receiving side, thereby allowing a lower bus share allocation for the stream. In this paper we present an algorithm that determines how much of the bus capacity and buffer space should be allocated to each stream, in order to have a feasible transmission schedule for each stream. Furthermore, the algorithm determines a transmission schedule for each stream, indicating how much data is transmitted over time. We show how this multiple-stream problem can be solved by repeatedly solving single-stream problems. We present efficient algorithms to solve these single-stream problems. Furthermore, we present some experimental results. This revised version was published online in September 2006 with corrections to the Cover Date.     

Influence of the underneath cavity on buoyant‐forced cooling of the integrated photovoltaic panels in building roof: a thermography study

Airflow around building‐integrated photovoltaics (BIPV) has a significant impact on their hygrothermal behavior and degradation. The potential of reducing the temperature of BIPV using an underneath cavity is experimentally and numerically investigated in literature. Most of the models are oversimplified in terms of modeling the impact of 3D flow over/underneath of PV modules, which can result in a non‐uniform surface temperature and consequently a non‐homogenous thermal degradation. Moreover, the simultaneous presence of radiation and convection related to upstream wind, in addition to the combined impact of back‐ventilation and surface convection, is barely addressed in literature. However, these simplifications can result in the unrealistic loading climate conditions. This paper aims to present a unique experimental setup to provide more realistic climate conditions for investigating the ventilation potential of the underneath. The setup consists of a solar simulator and a building prototype with installed PV, placed inside an atmospheric wind tunnel to control upstream wind velocity. Thermography is performed using an infrared camera to monitor the surface temperature of the BIPV. The potential of an underneath cavity with various cavity heights and PV arrangement is further investigated in this paper. The outcome would be eventually useful in the development of practical guidelines for BIPV installation. Copyright © 2013 John Wiley & Sons, Ltd.     

Demonstration of the monolithic interconnection on CIS solar cells by picosecond laser structuring on 30 by 30 cm2 modules

In this paper, we present the selective structuring of all three patterns (P1, P2 and P3) of a monolithic interconnection of CIS (Cu(In,Ga)(S,Se)₂) thin film solar cells by picosecond laser pulses at a wavelength of 1064 nm. We show results for single pulse ablation threshold values and line scribing of molybdenum films on glass (P1), CIS on molybdenum (P2) and zinc oxide on CIS (P3). The purposes of these processes are the p‐type isolation (P1), cell interconnect (P2) and n‐type isolation (P3), which are required for complete cell architecture. The half micron thick molybdenum back electrode can be structured with a process speed of more than 15 m/s at about 15 W average power without detectable residues and damage by direct induced laser ablation from the back side (P1). The CIS layer can be structured selectively down to the molybdenum at process speeds up to 1 m/s at about 15 W average power, due to the precision of direct laser ablation in the ultrashort pulse regime (P2). The ZnO front electrode layer is separated by clean trenches with straight side walls at process speeds of up to 15 m/s at about 10 W average power, as a result of indirect induced laser ablation (P3). A validation of functionality of all processes is demonstrated on CIS solar cell modules (30 × 30 cm²). By replacing one state‐of‐the‐art process by a picosecond laser process at a time, solar efficiencies could be increased for P1 and P2 and stayed on a similar level for P3. After an optimization of the patterning processes in the R&D pilot line of AVANCIS, we achieved a new record efficiency for an all‐laser‐patterned CIS solar module: 14.7% as best value for the aperture area efficiency of a 30 × 30 cm² sized CIS module was reached. Copyright © 2014 John Wiley & Sons, Ltd.     

Highly Utilized Active Sites on Pt@Cu/C for Ethanol Electrocatalytic Oxidation in Alkali Metal Hydroxide Solutions

Using ethanol electrocatalytic oxidation reaction (EOR) with a lower reaction potential to replace oxygen evolution reaction (OER) and integrating hydrogen evolution reaction (HER) have a promising development prospect for more energy-saving electrolytic hydrogen production. However, the main challenges of EOR are insufficient catalytic activity, high overpotential, and slow kinetics. Active sites on the electrocatalysts surface are occupied by alkali metal ion hydrate clusters by noncovalent interactions, which is considered to be one of the major causes of these challenges. To reduce the effect of the noncovalent interactions on the catalytic activity of the electrocatalyst, copper is chosen and doped in the form of a single atom in the electrocatalyst (Pt@Cu/C) to increase the electrocatalyst conductivity and make the anode contain more positive charge in this study. Then, alkali metal ion hydrate clusters are difficult to adsorb at the active site of Pt@Cu/C. The EOR electrocatalytic activity of Pt@Cu/C is up to 8184 mA mg_Pt⁻¹, which is ≈4.8 times as high as that of Pt/C. The two-electrode hydrogen production device using Pt@Cu/C as anode for coupled EOR&HER requires a smaller voltage of 0.60 V to reach 10 mA cm⁻² compared with that of Pt/C (0.76 V).     

A novel propagation modeling for microcellular communications inurban environments

A novel method for microcellular communications to predict propagation characteristics is presented in this paper. It takes into account multiple reflections among walls, ground, vehicles, as well as the transmission/reflection due to groups of trees. Although these are three-dimensional (3-D) problems, we can combine two-dimensional (2-D) ray tracing and simple 3-D geometric considerations to solve them in a very efficient way. We have investigated the propagation loss versus size, number, and locations of vehicles and groups of trees on a safe island. Our results show that the radio wave propagation exhibits severe fast fading, attenuation, and blockage due to reflection, transmission, and shadowing, respectively     

Determination of aryloxyphenoxypropanoic acid derivatives in crops treated with herbicidal sprays

Summary A reproducible and sensitive gas Chromatographic method has been developed for the trace analysis of fluazifop-butyl, haloxyfop-ethoxyethyl and quizalofop-ethyl as well as their main metabolites (corresponding acids analysed after conversion to methyl esters) in some fruits and vegetables treated with herbicidal sprays. Comparable detection limits (0.01 mg/kg) were achieved when mass fragmentography and/or the electron capture detector were employed. However, in the latter case, bromination of fluazifop esters had to be carried out prior to GC analysis. By means of the nitrogen-phosphorus detector, determination of residues at a level of 0.05 mg/kg was possible. The residue values found in strawberries, cabbages, cauliflowers and carrots were used to discuss the degree of metabolic hydrolysis of parent esters, i.e. active ingredients of herbicides.

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Bestimmung von Aryloxyphenoxypropionsäure-Derivaten in mit Herbicidsprays behandelten Produkten

Zusammenfassung Es wurde eine gaschromatographische Methode zur quantitativen und selektiven Bestimmung von Fluazifop-butyl, Haloxyfop-ethoxyethyl und Quizalofop-ethyl sowie von ihren Hauptmetaboliten (den entsprechenden Säuren, die zu Methylestern umgesetzt werden müssen) in mit Herbiciden behandelten Obst- und Gemüseproben entwickelt. Eine Nachweisgrenze von 0,01 mg/kg wurde durch Elektroneneinfanggaschromatographie oder durch Massenfragmentographie erzielt. Um die gleiche Empfindlichkeit des EC-Detektors bei Fluazifop zu erreichen, wurden die beiden Ester mit Brom umgesetzt. Mit Hilfe des NP-Detektors konnte eine Nachweisgrenze von 0,05 mg/kg erreicht werden. Die festgestellten Rückstandsgehalte in Erdbeeren, Kohl, Blumenkohl und Möhren wurden gleichzeitig zur Beurteilung der metabolischen Hydrolyse der diskutierten Ester (der Wirkstoffe der Herbicide) herangezogen.

     

Approach to stress tests in SIP environment based on marginal analysis

In the field of performance metrics and measurements of SIP (Session Initiation Protocol) Proxy and B2BUA (Back-to-Back User Agent) no standardized methodology has been presented yet. This gap results in a problematic determination of a hardware, the performance of which would be cost-effective and sufficient for the running the SIP Server in a given environment. Today practice relies on the administrator’s skills and experience with the needs of the telephony infrastructure. From this and the increasing usage of SIP based VoIP technologies come the main reasons for creating a methodology that would allow administrators to precisely measure the SIP Server performance and compare it to other software and hardware platform. This work also utilizes SIP Server performance measurements to comparison the results taken when transcoding was in use and when it was not and provides the means for comparison of B2BUAs platform independently.     

Identifying peer‐to‐peer communities in the network by connection graph analysis

In this paper we present a unified solution to identify peer‐to‐peer (P2P) communities operating in the network. We propose an algorithm that is able to progressively discover nodes cooperating in a P2P network and to identify that P2P network. Starting from a single known node, we can easily identify other nodes in the P2P network, through the analysis of widely available and standardized IPFIX (NetFlow) data. Instead of relying on the analysis of content characteristics or packet properties, we monitor connections of known nodes in the network and then progressively discover other nodes through the analysis of their mutual contacts. We show that our method is able to discover cooperating nodes in many P2P networks and present the real computational requirements of the algorithm on a large network. The use of standardized input data allows for easy deployment onto real networks. Copyright © 2014 John Wiley & Sons, Ltd.     

B-spline explicit active surfaces: an efficient framework for real-time 3-D region-based segmentation

A new formulation of active contours based on explicit functions has been recently suggested. This novel framework allows real-time 3-D segmentation since it reduces the dimensionality of the segmentation problem. In this paper, we propose a B-spline formulation of this approach, which further improves the computational efficiency of the algorithm. We also show that this framework allows evolving the active contour using local region-based terms, thereby overcoming the limitations of the original method while preserving computational speed. The feasibility of real-time 3-D segmentation is demonstrated using simulated and medical data such as liver computer tomography and cardiac ultrasound images.