16953383
Extending the SCR Method for Real-Time Systems
Wepropose timed SCR specifications, which are a generalizationof SCR specifications, intended to specify quantitative timingproperties of real-time systems. We extend the tabular notationof the SCR method to deal with sporadic and periodic timing constraints.We present a formal semantics for timed SCR specifications bytranslating them into timed transition systems. A shutdown systemin Korean nuclear power plants is used as a case study to illustratetimed SCR specifications.
195642367
Co-Validation Environment for Memory Card.
423782
Evolutionary Learning of Modular Neural Networks with Genetic Programming
Evolutionary design of neural networks has shown a great potential as a powerful optimization tool. However, most evolutionary neural networks have not taken advantage of the fact that they can evolve from modules. This paper presents a hybrid method of modular neural networks and genetic programming as a promising model for evolutionary learning. This paper describes the concepts and methodologies for the evolvable model of modular neural networks, which might not only develop new functionality spontaneously, but also grow and evolve its own structure autonomously. We show the potential of the method by applying an evolved modular network to a visual categorization task with handwritten digits. Sophisticated network architectures as well as functional subsystems emerge from an initial set of randomly-connected networks. Moreover, the evolved neural network has reproduced some of the characteristics of natural visual system, such as the organization of coarse and fine processing of stimuli in separate pathways.
42619529
EIMD: A New Congestion Control for Fast Long-Distance Networks
In fast long-distance networks, TCP fails to fully utilize the bandwidth due to its congestion control mechanism A plethora of congestion control schemes that may enhance the performance of the transport protocol in fast long-distance networks have been proposed The proposed schemes aim to satisfy three requirements of congestion control schemes: bandwidth scalability, TCP friendliness, and RTT fairness However, due to the trade-off among these requirements, it is difficult to satisfy all the requirements simultaneously In this paper, we propose a new window-based congestion control scheme called EIMD (Exponential Increase/Multiplicative Decrease) that increases congestion window size exponentially to quickly grap the unutilized bandwidth We evaluate the performance of EIMD via computer simulations The simulation results show that EIMD satisfies the three requirements In addition, EIMD converges fast to the fair-share points.
10122388
Modular neural networks evolved by genetic programming
We present an evolvable model of modular neural networks which are rich in autonomy and creativity. In order to build an artificial neural network which is rich in autonomy and creativity, we have adopted the ideas and methodologies of artificial life. The paper describes the concepts and methodologies for the evolvable model of modular neural networks, which will be able not only to develop new functionality spontaneously but also to grow and evolve its own structure autonomously. Although the ultimate goal of this model is to design the control system for such behavior based robots as Khepera, we have attempted to apply the mechanism to a visual categorization task with handwritten digits. The evolutionary mechanism has shown a strong possibility to generate useful network architectures from an initial set of randomly connected networks.
34099032
Aggregated Aggressiveness Control on Groups of TCP Flows
The use of multiple concurrent parallel TCP flows is an easy way to achieve higher speed reliable data transfers. However, parallel TCP flows are inherently unfair with respect to single TCP flows. We suggest a new scheme called TCP-P, which controls aggressiveness of a group of parallel TCP flows by regulating their total aggressiveness (or unfairness) to be comparable to a single TCP flow, or any multiple thereof. TCP-P makes a group of N parallel TCP flows appear to other flows like k separable TCP flows – i.e., have strength k – through appropriate manipulations of increase and decrease behavior of the congestion windows of the TCP flows in the group. We implemented our scheme as part of Linux and experimental results show that the proposed scheme effectively controls aggressiveness of parallel TCP flows.
18832102
TCP Performance Improvement with ACK Pacing in Wireless Data Networks
Wireless data services are fundamental in ubiquitous networks. In wireless data networks, the TCP congestion mechanism can mistake a wireless channel error or blackout for congestion on the route. Several wireless TCP protocols have been proposed considering TCP performance degradation in wireless systems. However, these protocols are too complex to deploy in wireless systems. In this paper, we propose the ACK Pacing algorithm for long lasting loss periods like a hand-off or a blackout. By pacing ACK packets sending, we prevent bursty data delivery to the old path and a spurious timeout occurrence. Also, paced ACK packets trigger the route update to the new path faster. The proposed algorithm can be implemented in the wireless-node-side which is easily applicable to wireless systems. From simulation results, ACK Pacing improves TCP performance compared with many TCP variations. The ACK Pacing algorithm shows good performance during a long lasting loss period.