Hybrid image steganography method using Lempel Ziv Welch and genetic algorithms for hiding confidential data

Multidimensional Systems and Signal Processing - Digital images are commonly used in steganography due to the popularity of digital image transfer and exchange through the Internet. However, the...     

Implantable central venous access devices in children with metabolic disease

We have inserted 20 totally implantable central venous devices in 17 patients with severe metabolic disease over a 43-month span. Patient ages ranged from 2 months to 17 years (mean, 4.2 years). The underlying pathology was Gaucher's disease in six patients, vitamin D-dependent rickets type II in five, propionic acidemia in two, and methylmalonic acidemia, 3-hydroxyl-3-methylglutaryl coenzyme A (CoA) lyase deficiency, fructose 1,6 diphosphatase deficiency, and urea cycle disorder in one child each. There were seven complications (six due to catheter-related infection and one due to occlusion of the system) during a total of 7,278 patient-catheter days. The infection rate was 0.8 per 1,000 days. Six catheters were removed due to complications and two due to completion of treatment. There were no operative complications or deaths. Our experience demonstrates that a totally implantable device may be useful in children with metabolic disease who need long-term venous access. Attention should be given to minimize the infection rate to reduce the rate of catheter removal.     

Sensitivity analysis of stand alone PV systems

Daily solar insulation is stochastic quantity. Therefore there is always a risk for a stand alone PV system not to meet the load, loads fed by PV systems widely vary by the importance. Therefore there should be different risk level for different loads, eg the loss of load risk (LOLR) level for rural house could be much less than that for telecommunication installation. Risk reduction is always accompanied by cost increase. This paper introduces a simple method to assess LOLR with least costs which can lead to better PV system design.     

Proportion assessment of combined PV-wind generating systems

The availability of sun and wind is often in contrast. This fact has led to the proposal of a combined generating system consisting of PV and Wind Generator. This paper introduces a method enabling the assessment of the optimal proportion of PV to wind generator capacities. The method is based on evaluation of costs and loss of load risk (LOLR). According to the Daily Electrical Energy Demand, the required generating system is designed with different alternatives: only PV, only wind generator and a combined PV and wind generator in various proportions. For each alternative, the costs and LOLR are evaluated. LOLR evaluation is performed using a probabilistic model introduced here. The alternatives are compared with each other and the optimal one is determined.     

Photovoltaic system for transmission substation application

This paper suggests using a photovoltaic system to supply the required power for the operation of switching substations. This suggestion is justified by the low power demand needed for this type of substations and the high cost of conventional means for performing this task. A design methodology for the PV system is described and a comparative study showing the superiority of photovoltaic system is given.