On the capacity of a cellular CDMA system

It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity     

The digi-neocognitron: a digital neocognitron neural network modelfor VLSI

One of the most complicated ANN models, the neocognitron (NC), is adapted to an efficient all-digital implementation for VLSI. The new model, the digi-neocognitron (DNC), has the same pattern recognition performance as the NC. The DNC model is derived from the NC model by a combination of preprocessing approximation and the definition of new model functions, e.g., multiplication and division are eliminated by conversion of factors to powers of 2, requiring only shift operations. The NC model is reviewed, the DNC model is presented, a methodology to convert NC models to DNC models is discussed, and the performances of the two models are compared on a character recognition example. The DNC model has substantial advantages over the NC model for VLSI implementation. The area-delay product is improved by two to three orders of magnitude, and I/O and memory requirements are reduced by representation of weights with 3 bits or less and neuron outputs with 4 bits or 7 bits.     

Computerised trace method for establishing equations for dimensions and tolerances in design and manufacture

A computerised trace method has been developed for determining the relationships of assembly requirements with design dimensions and tolerances of the components in an assembly, and the relationships of design specifications and machining allowance requirements with manufactured dimensions and tolerances of the component in a process plan. This method traces from the proposed components or planned operations only the dimensions and tolerances that affect the given requirement, and therefore the equations for design or for manufacture can be established simultaneously and accurately. Hence it is possible to establish constraints for the optimisation of dimensions and tolerances for design or for manufacture.     

Effect of the chemical composition of Fe-Mn-C-P alloys on the brittle-ductile transition temperature in the solidification range

The brittle-ductile transition temperature in the solidification range depends on the composition of the phase which solidifies as the last one. The paper presents a thermochemical study of Fe-Mn-C-P system, determining the conditions of crystallisation of carbides, phosphides and the pseudo-ternary eutectic M^L-M₃C-M₃P. Manganese raises the phosphorus concentration in eutectic. The eutectic temperature attains its maximum at about 6% of Mn. Then the brittle-ductile transition temperature is about 30 K higher than in ternary Fe-C-P alloy. A further raise is possible when the alloy is modified by an element forming stable, solide carbide, for ex. titanium. The results of theoretical analysis were verified by experimental work. The influence of titanium on the inclusions appearing in the vicinity of hot cracks of Hadfield cast steel has been studied.     

Structural vibrations of hydraulic structures at the boundary with fluid regions with a complex shape (three-dimensional problem)

Translated from Gidrotehnicheskoe Stroitel'stvo, No. 3, pp. 27–31, March, 1992.     

Influence of laminar lubricants on the structure,character of failure,and properties of silver-base electrical contact materials

Translated from Poroshkovaya Metallurgiya, No. 6(354), pp. 58–69, June, 1992.     

New full-voltage-swing BiCMOS buffers

Circuit techniques are presented for increasing the voltage swing of BiCMOS buffers through active charging and discharging using complementary bipolar drivers. These BiCMOS circuits offer near rail-to-rail output voltage swing, higher noise margins, and higher speed of operation at scaled-down power supply voltages. The circuits are simulated and compared to BiCMOS and CMOS buffers. The comparison shows that the conventional BiCMOS and the complementary BiCMOS buffers are efficient for power supply voltages greater than 3V and that if the power supply voltage is scaled down (<3 V) and the load capacitance is large (>1 pF), the complementary BiCMOS buffers would be the most suitable choice. They provide high speed and low delay to load sensitivity and high noise margins. The first implementation is favorable near a 2.5-V power supply for its smaller area     

Effects of nicotinamide and oxythiamine on the lipogenic parameters of the adipose tissue of mice with non-insulin-dependent type of experimental diabetes mellitus and hyperinsulinemia]

The influence of nicotinamide and oxythiamine on the activity of NADPH-producing dehydrogenases of glucoso-6-phosphate, 6-phosphogluconate, malate, isocitrate, as well as concentration and synthesis rate of fatty acids in fatty tissue were studied in experiments on mice with genetically conditioned non-insulin-dependent diabetes and hyperinsulinemia. It has been established that in these diseases the synthesis of fatty acids and their inclusion into lipids are activated without increasing the above enzymes activity. It is shown that nicotinamide and oxythiamine inhibit inclusion of C from glucose into free fatty acids, antivitamin intensifies lipolysis in the fatty tissue of the diseased animals.