A recursive method for breaking complex logic loops in Boolean system models

A finite iterative method is developed for solving system fault trees containing logic loops. The procedure yields correct expressions for the top events as well as for all intermediate gates.     

RF MEMS impedance tuners for 6–24 GHz applications

RF MEMS tuners with wide impedance coverage have been developed for 6–24 GHz noise parameter and load‐pull measurement systems. The tuners are based on triple‐, double‐, and single‐stub topologies loaded with switched MEMS capacitors. Several designs are presented, and they use 10–13 switched MEMS capacitors to produce 1024–8192 (2¹⁰–2¹³) different impedances. The measured impedance coverage agrees well with simulations and it is the widest ever measured impedance coverage from any planar tuner to‐date. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.     

Image quality assessment using block-based weighted SVD

Image quality is an important challenge in image processing. The quality measures should be designed in the direction where the correlation between the mathematical evaluation and subjective evaluation is high. We propose a new image quality assessment relying on block-based singular vectors. The corresponded distorted blocks are projected onto the singular vector matrices of the original blocks. These projection coefficients are the main quality attribute. The algorithm is further developed into the reduced reference method. Eigenvectors of the covariance matrix of all original blocks are used as the constant basis to compute the projecting coefficients of all original and distorted blocks. Simulation results on different databases with various distortion types and comparison to state-of-the-art methods show the proposed method in most cases gives the best correlation with human evaluation.     

Ad Hoc LTE Method for Resilient Smart Grid Communications

Wireless Personal Communications - LTE network is a good choice for delivering smart grid demand response (DR) traffic. However, LTE connectivity is not pervasively available due to smart meter...     

Power-to-ammonia in future North European 100 % renewable power and heat system

Power-to-gas and other chemicals-based storages are often suggested for energy systems with high shares of variable renewable energy. Here we study the North European power and district heat system with alternative long-term storage, the power-to-ammonia (P2A) technology. Assuming fully renewable power and heat sectors and large-scale electrification of road transport, we perform simultaneous optimization of capacity investments and dispatch scheduling of wind, solar, hydro and thermal power, energy storages as well as transmission, focusing on year 2050. We find that P2A has three major roles: it provides renewable feedstock to fertilizer industry and it contributes significantly to system balancing over both time (energy storage) and space (energy transfer). The marginal cost of power-based ammonia production in the studied scenarios varied between 431 and 528 €/t, which is in the range of recent ammonia prices. Costs of P2A plants were dominated by electrolysis. In the power and heat sector, with our cost assumptions, P2A becomes competitive compared to fossil natural gas only if gas price or CO₂ emission price rises above 70 €/MWh or 200 €/tCO₂.     

Cuckoo search for wind farm optimization with auxiliary infrastructure

This paper focuses on the optimization problem of a wind farm layout. This area of research is currently receiving widespread attention, as optimal positioning of the turbines promotes the financial viability of the wind farm and enhances the competitiveness of wind projects in the energy market. In this work, cuckoo search (CS), a modern population‐based metaheuristic optimization algorithm, is used. The objective is to find the turbine layout and types that maximize the net present value of the wind farm, while constraints on the turbine positions have to be met. The following constraints are considered: Firstly, the minimum distance between turbines for safe operation; secondly, a realistic wind farm shape including forbidden zones for installation and the existing infrastructure. Furthermore, the optimization of the wind farm includes an algorithm to find the least expensive layout of the wind farm roads and the electrical collector system. The algorithm is based on Dijkstra's shortest path and Prim's minimum spanning tree algorithms. The test results indicate that the infrastructure cost has a significant effect on the optimum wind farm solution. A genetic algorithm, commonly applied to wind farm micro‐siting problems, is used to benchmark the performance of the CS. The results show that the CS is capable of consistently finding better solutions than the genetic algorithm.     

Potential probiotic characteristics of Lactobacillus and Enterococcus strains isolated from traditional dadih fermented milk against pathogen intestinal colonization

Traditional fermented buffalo milk in Indonesia (dadih) has been believed to have a beneficial impact on human health, which could be related to the properties of the lactic acid bacteria (LAB) involved in its fermentation process. In previous studies, it was discovered that strains of dadih lactic isolates possessed some beneficial properties in vitro. In the present study, the adhesion capacity of specific LAB isolates from dadih to intestinal mucus was analyzed. Further, the ability to inhibit model human pathogens and displace them from mucus was assessed. The adhesion of tested LAB strains was strain-dependent and varied from 1.4 to 9.8%. The most adhesive Lactobacillus plantarum strain was IS-10506, with 9.8% adhesion. The competition assay between dadih LAB isolates and pathogens showed that a 2-h preincubation with L. plantarum at 37 degrees C significantly reduced pathogen adhesion to mucus. All tested LAB strains displaced and inhibited pathogen adhesion, but the results were strain-specific and dependent on time and pathogen strains. In general, L. plantarum IS-10506 showed the best ability against pathogen adhesion.     

Fan pressure-based testing,adjusting, and balancing of a ventilation system

Ventilation systems are responsible for the thermal comfort and air quality of indoor spaces. The adjustment of ventilation systems is a time-consuming task that may need multiple iterations. Incorrect adjustments of a ventilation system can reduce the quality of working and living conditions and degrade the energy efficiency of the ventilation. In this paper, a testing, adjusting, and balancing method for a ventilation system is presented that uses only the knowledge of the fan total flow rate and pressure. The method does not need additional instrumentation for the ventilation adjustment as the fan operating point can be estimated with the variable-speed drive. The method is noniterative, thereby saving time, and the ventilation system is adjusted to its minimum energy consumption setting without compromise in system operation. The proposed method is assessed with a laboratory test setup to verify the correct operation of the method in practice.     

Reversible surface binding of cadmium and lead by lactic acid and bifidobacteria

Extensive cadmium and lead contamination of water has been reported to occur locally as a result of human activities. Lactic acid bacteria have been reported to remove cadmium and lead from water. The aim of this work was to clarify the mechanisms of cadmium and lead removal from water. In addition, the effect of other metals, reversibility of binding and recyclability of the biomass was assessed. Based on our earlier data, the two most promising lactic acid bacteria, Lactobacillus fermentum ME3 and Bifidobacterium longum 46, were selected for these experiments. The results showed that the presence of other cationic metals and blocking of carboxyl and phosphoryl groups reduced cadmium and lead removal. These results suggest involvement of electrostatic interactions in cadmium and lead removal, and support our earlier findings. Transmission electron micrographs showed large deposits of lead on the bacterial surface suggesting formation of metallic lead precipitates. Both cadmium and lead removal were reversible processes established by full recovery of removed metal after desorption with dilute solutions of EDTA and HNO(3). Resorption capacity of both biomasses tested was reduced after regeneration with 10 mM EDTA and 15 mM HNO(3). Taken together, the results suggest involvement of several reversible mechanisms such as ion exchange and precipitation in cadmium and lead binding by lactic acid bacteria. The results show that specific lactic acid bacteria have the potential for removal of cadmium and lead from water although reduction in resorption capacity after regeneration of the biomass may form a problem. Since the studies so far have mainly focused on removal of single metals from pure water, metal removal in conditions of natural waters should be assessed in further experiments.