Power dissipation is an important issue in VLSI circuit design. This paper emphasizes on adaptive leakage control using body bias technique to reduce the power dissipation of the 65 nm MOS devices. Through adding forw...
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ISBN:
(纸本)9781424429523
Power dissipation is an important issue in VLSI circuit design. This paper emphasizes on adaptive leakage control using body bias technique to reduce the power dissipation of the 65 nm MOS devices. Through adding forward body biasing, the leakage is reduced in sub-100 nm CMOS devices (unlike above-100 run devices) while slightly increasing the signal propagation delay. For the conditions where the circuit does not use up the entire clock cycle, this slack can be used to reduce the power dissipation without any loss in performance. The fact that the circuit delay remains less than the clock period provides the opportunity to reduce power consumption of VLSI circuits. The objective is to change the voltage of the body bias to reduce leakage, allowing the circuit to consume less power whenever the clock edge can be met as detected beforehand.
This paper proposes a novel low-power fully asynchronous ACS module of the Viterbi decoder to improve the shortcomings of low throughput and high power consumption in conventional synchronous ACS module. The computati...
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This paper proposes a novel low-power fully asynchronous ACS module of the Viterbi decoder to improve the shortcomings of low throughput and high power consumption in conventional synchronous ACS module. The computation quantity can be reduced by adopting pre-computation algorithm which can select the survival path ahead of time. We use Null Convention Logic to implement the fully asynchronous circuits to reach lowpower and delay-insensitive. These qualities allow the module working at the maximum speed environment permits,and meanwhile avoid performance degradation in conventional synchronous design brought by critical path. Results have demonstrated that the design proposal in this paper has a throughput improvement by 36.3% and a power consumption reduced by 30.1% over the synchronous one. The novel design is suitable for low-power wireless communication applications with the characteristics of glitch immunization,delay-insensitive and speed adaptive.
Energy-efficiency is one of the main concerns in the wireless information dissemination system. This paper presents a wireless broadcast stream organization scheme which enables complex queries (e.g., aggregation quer...
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Energy-efficiency is one of the main concerns in the wireless information dissemination system. This paper presents a wireless broadcast stream organization scheme which enables complex queries (e.g., aggregation queries) to be processed in an energy-efficient way. For efficient processing of complex queries, we propose an approach of broadcasting their pre-computed results with the data stream, wherein the way of replication of index and pre-computation results are investigated. Through analysis and experiments, we show that the new approach can achieve significant performance enhancement for complex queries with respect to the access time and tuning time.
For Viterbi decoders, high throughput rate is achieved by applying look-ahead techniques in the add-compare-select unit, which is the system speed bottleneck. Look-ahead techniques combine multiple binary trellis step...
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ISBN:
(纸本)9781424429233
For Viterbi decoders, high throughput rate is achieved by applying look-ahead techniques in the add-compare-select unit, which is the system speed bottleneck. Look-ahead techniques combine multiple binary trellis steps into one equivalent complex trellis step in time sequence, which is referred to as the branch metrics precomputation (BMP) unit. The complexity and latency of BMP increase exponentially and linearly with respect to the look-ahead levels, respectively. For a Viterbi decoder with constraint length K and M-step look-ahead, 2(M+K-1) branch metrics need to be computed and compared. In this paper, the computational redundancy in existing branch metric computation approaches is first recognized, and a general mathematical model for describing the approach space is built, based on which a new approach with minimal complexity and latency is proposed. The proof of its optimality is also given. This highly efficient approach leads to a novel overall optimal architecture for M that is any multiple of K. The results show that the proposed approaches can reduce the complexity by up to 45.65% and the latency by up to 72.50%. In addition, the proposed architecture can also be applied when All is any value while achieving the minimal complexity.
Exponentiation is an important mathematical operation in many areas, and is constantly being researched for more efficient methods. This paper presents a power efficient implementation of integer modular exponentiatio...
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ISBN:
(纸本)9781424429202
Exponentiation is an important mathematical operation in many areas, and is constantly being researched for more efficient methods. This paper presents a power efficient implementation of integer modular exponentiation using discrete logarithm transformation. By transforming the base of an exponent, this method is able to perform modular exponentiation without the use of multipliers. Originally developed and implemented for high speed applications, this method has been modified and implemented for low power while maintaining comparable performance. The design is created and simulated with a repetitive-square design for comparison purpose. The two circuits are compared in terms of speed and power consumption. Results show that for bus sizes greater than 32 bit, the proposed design is able to use only approximately 40% of the power that the repetitive-square counterpart consumes.
This paper presents an iterative construction method for building composite permutations. Its efficiency is based on the concepts of pre-computation and equivalence classes. Equivalence class representatives of permut...
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This paper presents an iterative construction method for building composite permutations. Its efficiency is based on the concepts of pre-computation and equivalence classes. Equivalence class representatives of permutations on four bits are pre-computed. These class representatives can serve as input to the construction method, however, the results are also of independent interest for applications in cryptography. A well-known example of a cryptosystem using composite permutations for its Substitution boxes (S-boxes) is the Data Encryption Standard (DES). Throughout the paper, DES-like S-boxes are defined as mappings satisfying all design criteria as disclosed by one of the designers of DES. All permutations on four bits with DES-like properties are identified. Starting with pre-computed representatives of classes with such permutations, two iterations of a specialized version of the algorithm are applied to obtain bounds on the minimum differential uniformity and minimum non-linear uniformity of DES-like S-boxes. It is established that the two values cannot be less than eight, and that DES-like S-boxes for which the values are both equal to 12 do exist. In addition, if the non-linear uniformity of each of the four permutations in a DES-like S-box is at most six, as in all DES S-boxes, then its non-linear uniformity cannot be less than ten and its minimum differential uniformity equals 12.
This paper presents a method to model leaves with realistic animation. Leaves' movement is consisted of three parts: leafstalk's rotation, leaf surface's rotation and bend. For each of them, a movement mod...
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ISBN:
(纸本)7506278413
This paper presents a method to model leaves with realistic animation. Leaves' movement is consisted of three parts: leafstalk's rotation, leaf surface's rotation and bend. For each of them, a movement model was constructed and the movement was computed based on each model, respectively. For the leafstalk, we regarded it as a spring-like thing, and it vibrates with the wind;for the leaf surface, wind force make it rotate around local y-axis and x-axis, which actually the surface's bend and rotation. The final leaves' movements were obtained by superposing these three movements. pre-computation and a new physically based model were developed to speedup the simulation. The result shows that this method is effect and easy to implement.
This paper presents a method to model leaves with realistic animation. Leaves' movement is consisted of three parts: leafstalk's rotation, leaf surface's rotation and bend. For each of them, a movement mod...
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This paper presents a method to model leaves with realistic animation. Leaves' movement is consisted of three parts: leafstalk's rotation, leaf surface's rotation and bend. For each of them, a movement model was constructed and the movement was computed based on each model, respectively. For the leafstalk, we regarded it as a spring-like thing, and it vibrates with the wind;for the leaf surface, wind force make it rotate around local y-axis and x-axis, which actually the surface's bend and rotation. The final leaves' movements were obtained by superposing these three movements. pre-computation and a new physically based model were developed to speedup the simulation. The result shows that this method is effect and easy to implement.
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