18135743
A clustering entropy-driven approach for exploring and exploiting noisy functions
Linear, Gaussian, fitness proportional, clustering, and Rosca entropies are succinct measures of diversity that have been applied to balance exploration and exploitation in evolutionary algorithms. In previous studies, an entropy-driven approach using linear entropy explicitly balances and/or searches optimal solutions for the selected unimodal and multimodal functions excluding noisy functions. This paper investigates the reasons for such an exception and introduces a clustering entropy-driven approach to solve the problem. Such an approach provides a coarse-grained diversity measure that filters the noise of functions, varies cluster size and categorizes individuals at the genotype level. The experimental results show that the clustering entropy-driven approach further improves the searching results of noisy functions by one more degree.
7160160
QoS-UniFrame: a Petri net-based modeling approach to assure QoS requirements of distributed real-time and embedded systems
Assuring quality of service (QoS) requirements is critical when assembling a distributed real-time and embedded (DRE) system from a repository of existing components. This paper presents a two-level approach for assuring satisfaction of QoS requirements in the context of a reduced design space for DRE systems. A dynamic and parallel approach is introduced to prune off the infeasible design spaces at the first level. Evolutionary algorithms cooperating with a domain-specific scripting language then discard less probable design spaces using statistics. These techniques fulfill the collective objectives of pruning and assuring the design space at system assembly time.
8071150
TCP-Illinois: A loss- and delay-based congestion control algorithm for high-speed networks
We introduce a new congestion control algorithm for high-speed networks, called TCP-Illinois. TCP-Illinois uses packet loss information to determine whether the window size should be increased or decreased, and uses queueing delay information to determine the amount of increment or decrement. TCP-Illinois achieves high throughput, allocates the network resource fairly, and is incentive compatible with standard TCP. We also build a new stochastic matrix model, capturing standard TCP and TCP-Illinois as special cases, and use this model to analyze their fairness properties for both synchronized and unsynchronized backoff behaviors. We finally perform simulations to demonstrate the performance of TCP-Illinois.
3186847
A Hardware/Software Framework for Real-Time Spiking Systems
One focus of recent research in the field of biologically plausible neural networks is the investigation of higher-level functions such as learning, development and modulatory functions in spiking neural networks. It is desirable to explore these functions in physical neural network systems operating in real-time. We present a framework which supports such research by combining hardware spiking neurons implemented in analog VLSI (aVLSI) together with software agents. These agents are embedded in the spiking communication of the network and can change the parameters and connectivity of the network. This new approach incorporating feedback from active software agents to aVLSI hardware allows the exploration of a large variety of dynamic real-time spiking network models by adding the flexibility of software to the real-time performance of hardware.
14515232
An investigation of the approach to specification-based program review through case studies
Software review is an effective means to enhance the quality of software systems. However, traditional review methods emphasize the importance of the way to organize reviews and rely on the quality of the reviewers' experience and personal skills. In this paper we propose a new approach to rigorously reviewing programs based on their formal specifications. The fundamental idea of the approach is to use a formal specification as a standard to check whether all the required functions and properties in the specification are correctly implemented by its program. To help investigate the effectiveness and the weakness of the approach, we conduct two case studies of reviewing two program systems that implement the same formal specification of "A Research Management Policy" using different strategies, and present the evaluation of the case studies. The results show that the review approach is effective in detecting faults when the reviewer is different from the programmer, but less effective when the reviewer is the same as the programmer.
7952210
Semi-automatic transformation from formal specifications to programs
As model-based formal methods (e.g. VDM, Z) are becoming popular for the development of safety-critical and complex systems in industry, automatic transformation from formal specifications to programs is an ideal and efficient approach to software production. However, it is impossible in general for this transformation to be fully automatic, because the language of first order logic used for specification is not decidable. This paper uses VDM (Vienna Development Method) as an example to investigate this difficulty, and proposes an approach to address the problem. Rules for automatically transforming abstract level VDM specifications are described and further transformation at a detailed level is discussed. Finally, further work towards the construction of a rule-based software system to support the transformation from VDM specifications to programs in general is addressed.
6161480
Homeostasis in a Silicon Integrate and Fire Neuron
In this work, we explore homeostasis in a silicon integrate-and-fire neuron. The neuron adapts its firing rate over long time periods on the order of seconds or minutes so that it returns to its spontaneous firing rate after a lasting perturbation. Homeostasis is implemented via two schemes. One scheme looks at the presynaptic activity and adapts the synaptic weight depending on the presynaptic spiking rate. The second scheme adapts the synaptic "threshold" depending on the neuron's activity. The threshold is lowered if the neuron's activity decreases over a long time and is increased for prolonged increase in postsynaptic activity. Both these mechanisms for adaptation use floating-gate technology. The results shown here are measured from a chip fabricated in a 2-µm CMOS process.