in this paper the problem of minimizing the total transmitting power subject to a fixedtotal bit rate in ofdm systems is considered. upper bounds on transmitting power and bit rate ofeach subcarrier can also be taken into account. in practice, the number of bits of each subcarriershould be integer and nonnegative. in this paper an analytical optimal solution is derived for thecase of assuming t...

Application of quantum-dot is a promising technology for implementing digital systems at nano-scale.  Quantum-dot Cellular Automata (QCA) is a system with low power consumption and a potentially high density and regularity. Also, QCA supports the new devices with nanotechnology architecture. This technique works </...

In network steganography methods based on packet length, the length of the packets is used as a carrier for exchanging secret messages. Existing methods in this area are vulnerable against detections due to abnormal network traffic behaviors. The main goal of this paper is to propose a method which has great resistance to network traffic detections. In the first proposed method, the sender embe...

With the deepening of drilling depth, difficulty engineering increases gradually due to complex geological conditions. The traditional mechanical method shows problems high energy consumption, low efficiency, long cycle and cost. Because characteristics rock, abrasiveness rock causes great wear bit, which becomes an important factor affecting rate. High voltage electric pulse (Abbreviated as HV...