Exact Essential-Hazard-Free State Minimization of Incompletely Specified Asynchronous Sequential Machines

To insure correct dynamic behaviour of asynchronous sequential machines, hazards must be eliminated for they may cause malfunctions of the whole system. However, Hazard-free state minimization has received almost no prior attention in the literature. This paper describes an exact algorithm for essential-hazard-free state minimization of incompletely specified asynchronous sequential machines. Novel techniques for the elimination of apparent and potential essential hazards are proposed and exploited in our algorithm. The algorithm has been implemented and applied to over a dozen asynchronous sequential machines. Results are compared with results of non-essential-hazard-free method SIS. Most of the tested cases can be reduced to essential hazard free flow tables

Contributions to the Design of Asynchronous Macromodular Systems

In this thesis, I advocate the use of macromodules to design and build robust and performance-competitive asynchronous systems. The contributions of the work relate to different aspects of the design of asynchronous macromodular systems. First, an architectural optimization for 4-phase systems is introduced. The goal of the optimization is to increase the performance of a system by increasing the level of concurrent activity in the sequencing of data processing stages. In particular, three new asynchronous sequencers are designed, which increase the throughput of the system. Existing asynchronous data paths do not operate correctly at this increased level of concurrency: data hazards may result. Interlock mechanisms are introduced to insure correct operation. The technique can also be regarded as a low-power optimization: The increased throughput can be traded for a significant reduction in the power consumption of the entire system. SPICE simulation results show that the new sequencers allow roughly twice the throughput of non-concurrent sequencers. The simulations also show that, after voltage scaling, energy dissipation is reduced by a factor of 2.5. Second, the use of pulses for efficient inter-module synchronization is introduced. The idea is complemented with the definition of a pulse-mode handshake protocol and the characterization of Pulse-Burst Operation (PBO), an important extension to traditional pulse-mode operation. Also, a basic set of macromodules, that efficiently implement control operations such as sequencing, selection, iteration, concurrency control, resource sharing, and arbitration is presented. Modules for interfacing pulse-mode circuits with traditional 2-phase and 4-phase circuits are also included in the set. Finally, the design of a packet switch is used to demonstrate the viability of pulse-mode macromodules to implement complex, high performance systems. The switch organization, its asynchronous operation, and the low control overhead introduced by pulse-mode macromodules result in a design that can handle 2.4 times the target throughput of 155 Mbits/Sec. Also, the switch is characterized by very low input-to-output latency. These results suggest that pulse-mode macromodules can keep control overhead low without introducing complex, unsafe timing considerations, two necessary conditions to achieve robust, performance-competitive systems

Performance Comparison of Time-Step-Driven versus Event-Driven Neural State Update Approaches in SpiNNaker

The SpiNNaker chip is a multi-core processor optimized for neuromorphic applications. Many SpiNNaker chips are assembled to make a highly parallel million core platform. This system can be used for simulation of a large number of neurons in real-time. SpiNNaker is using a general purpose ARM processor that gives a high amount of flexibility to implement different methods for processing spikes. Various libraries and packages are provided to translate a high-level description of Spiking Neural Networks (SNN) to low-level machine language that can be used in the ARM processors. In this paper, we introduce and compare three different methods to implement this intermediate layer of abstraction. We have examined the advantages of each method by various criteria, which can be useful for professional users to choose between them. All the codes that are used in this paper are available for academic propose.EU H2020 grant 644096 ECOMODEEU H2020 grant 687299 NEURAM3Ministry of Economy and Competitivity (Spain) / European Regional Development Fund TEC2015-63884-C2-1-P (COGNET

The Extended Synthesis: Something Old, Something New

Abstract The eclipse of Darwinism began to end in the 1980s and hangs in the balance today. We need an Extended Synthesis, using “extension” metaphorically. We must extend back in time to recover important aspects of Darwinism that were set aside, and then lost during neo-Darwinism, then move forward beyond neo-Darwinism to encompass new data and concepts. The most comprehensive framework for the Extended Synthesis is the Major Transitions in Evolution. The Extended Synthesis rests comfortably within a philosophical perspective in which biology does not need to be connected with other areas of science in order to justify itself. I am attracted to an older concept in which biology needs a covering law to connect it with the rest of the natural sciences. Darwin implicated a “higher law,” but did not specify it. If we can elucidate that law, the Extended Synthesis will become the Unified Theory of Biology called for by Brooks and Wiley 25 years ago

Avances en la inmunosupresión para el trasplante renal. Nuevas estrategias para preservar la función renal y reducir el riesgo cardiovascular

The development of new immunosuppressants for renal transplantation is aimed not only at improving short-term outcomes, but also at achieving better safety, cardiovascular, and metabolic profiles and at decreasing nephrotoxicity. Belatacept is a fusion protein that inhibits T cell activation by binding to CD80 and CD86 antigens. Clinical trials, particularly the BENEFIT and BENEFIT-EXT studies, have shown that belatacept preserves function and structure in renal grafts. The effects of belatacept provide long-term, sustained results, and the safety and efficacy of this drug have been demonstrated in cases of renal transplantation from expanded criteria donors. Compared to calcineurin inhibitors, belatacept is associated with a lower incidence of chronic allograft nephropathy and a more favourable cardiovascular and metabolic profile