Charge tunneling events in an ac-voltage-driven asymmetric single-electron transistor (aSET) under appropriate gate charge are rectified due to the tilted Coulomb blockade (CB) diagram, which induces a finite dc electric current even under zero dc biasing. We demonstrate dependence of the dc current upon the gate charge and the amplitude of the ac voltage by means of numerical simulation based on the Monte Carlo method. Device parameters of the aSET optimized for generation of the ac-induced dc current are derived by both analytical and numerical methods.

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The flat fading channel approximation error is investigated when employed for propagation channel modeling in wireless systems. The contributions of this paper are as follows. First, a bound for the approximation error is derived which is tighter in comparison with previously reported expressions. Second, practical error bounds are presented for WLAN systems in a typical indoor channel situation. The error bounds are derived as a function of the channel coherence bandwidth.

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A new design principle of optical burst switching (OBS) networks of ring configuration cooperating with static wavelength-division multiplexed (WDM) optical add/drop multiplexers (OADMs) is described. The paper indicates that wavelength-bypassing provided by the OADMs improves burst transport in several ways. For example, the bypassing makes the size of OBS switch fabric and mean hop-counts small. The paper focuses on burst loss rate performance. An optimum design to minimize burst loss rate in an OBS ring network under a given WDM level and the number of nodes is formulated through theoretical analysis. Simulation results show good agreement with the theory.

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An improved soft switching dual-switch forward converter topology is proposed in this paper. Compared with conventional dual-switch forward converter, the proposed converter employs an auxiliary switch and a clamp capacitor to instead of two reset diodes. Therefore, its duty cycle can exceed 0.5 to achieve wide range input voltage, also soft switching can be achieved for all switches. Especially, voltage stress across main switches can be clamped at 1/2V_in, voltage stress across auxiliary switch can be clamped at V_in. In addition, due to clamp capacitor series with the transformer, duty ratio can be extended with equation V_o = {V_in(1-D)D}/N. Thus, as a kind of better cost-effective approach, it is very attractive for high input, wide range and high efficiency application.

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