System synthesis domain level

There exist a number of approaches for the controller synthesis of system and component-level behavior models from system specifications which considers no time (e g. [29,30]). Current work in this domain focuses on synthesis approaches based on modal transition systems (e.g.[31]). The motivation of these approaches is to capture the possible system or component implementations. In general, these approaches are also able to restrict the forbidden behavior by properties. 

Within each of the two classical domains, bacteria and eucarya, reciprocal combinations of ribosomal subunits from distantly related organisms yield synthetically active hybrid ribosomes [174-176], In contrast, formation of hybrid particles from eucaryal and bacterial ribosomal subunits appears to be subject to severe constraints [174], One case of hybrid monosome formation from subunits of bacterial E. coli) and eucaryal ribosomes Artemia salina) has been reported by Boublik et al. [177] hybrid ribosomes (73S), however, were assembled only from Artemia 40S subunits and E. coli SOS subunits, and only at levels (30mM) considerably higher -about twofold - than those (ISIS mM) normally required for poly(U)-directed poly(Phe) synthesis in both bacterial and eucaryal cell-free systems. 

Fig. 7.4. Developmental path for the mechanism of intercellular communication by cAMP signals in D. discoideum, in agreement with the variations observed for the activity of adenylate cyclase and phosphodiesterase after starvation. The diagram is constructed as indicated in fig. 7.2, for system (5.1) to which the term (-k a) has been added in the evolution equation for variable a, to take into account the utilization of ATP to ends other than cAMP synthesis. In these conditions, the developmental path accounting for the sequential transitions of fig. 7.1 corresponds to the increase in the two enzyme activities that is observed in the hours that follow starvation (fig. 7.3). Domains A, B and C have the same meaning as in fig. 7.2 domain D corresponds to a stable steady state characterized by an elevated level of cAMP, while two stable steady states can coexist in E. The signal considered for amplification in B is y = 10. Parameter values are V = 0.04 s, k, - 0.4 s k = 10" s", = 10, L = lO", q = 100 (Goldbeter Segel, 1980).

The H2 receptor is a 359-amino-acid protein in humans. It has some features similar to the Hi protein (e.g., N-terminal glycosylation sites) and phosphorylation sites in the C-terminal. An aspartic acid residue in the third transmembrane loop appears to be critical to agonist and antagonist binding, and threonine/aspartate and tyrosine/aspartate couples in the fifth transmembrane domain appear to be important for interaction of the imidazole part of the histamine molecule. It is positively coupled via Gas to activate adenylyl cyclase for synthesis of cyclic adenosine monophosphate (cAMP) as a second messenger. In some systems, it is coupled through Gq proteins to stimulate phospholipase C. It appears in some cells that other processes, such as breakdown of phosphoinositides, control of intracellular calcium ion levels, and phospholipase A2 activity, can be regulated by other cAMP-independent pathways. 

The presented approach has been successfully tested on some high-level synthesis benchmarks. Although the fifth order elliptic filter benchmark is not representative for the investigated application domain, it was submitted to the synthesis system, mainly for testing the synthesis fiow. The example could be mapped successfully onto the emulator board, and the scheduling results are comparable to the best reported in literature. 

The goal of the hardware synthesis work within these projects has been to contribute design methodologies and synthesis techniques which address the design trajectory from real behavior down to the RT-level structural specification of the system. In order to provide complete support for this synthesis trajectory, many design problems must be tackled. We do not claim to cover the complete path, but we do believe we have contributed to the solution of a number of the most crucial problems in the domains of specification and synthesis. We therefore expect this book to be of interest in academia not for detailed descriptions of the research results—these have been published elsewhere—but for the overview of the field and a view on the many important but less widely known issues which must be addressed to arrive at industrially relevant results. 

In the above representation, the starting point for high-level synthesis is a behavioral domain specification at levels above the logic level. We will assume that the behavior is specified in a sequential (procedural, imperative) Hardware Description Language (HDL) such as sequential VHDL. Synchronous systems can be described in terms of a simple model of time using basic time units called control steps (cycles, or states of a finite automaton). The initial design... 

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