Partial exploration

How might this held develop in the future At this time, the chemistry of 1-silaallenes is fairly well understood, and that of 1-germaallenes is at least partially explored. Perhaps the series can be extended to 1 -stannaallenes, but these are predicted to have quite limited stability. The isolation of the 1,2.3-tristannaallcne shows that any combination of heteroatoms may be combined to form allenes... 

We have been fully occupied by our explorations. There has been no attempt as yet, in our laboratories or in others , to apply the chemistry to the synthesis of natural products or pharmaceuticals there has been no attempt to utilize the chemistry for industrial requirements, nor has there yet been any systematic effort to develop the physical organic aspects of this area. All that is still before us. Another major task before us is that of educating students in the experimental methods and techniques of this area of chemistry so that they will not hesitate to apply these fascinating new methods. Clearly we have uncovered a new continent, only partially explored. It will require a major effort on the part of many chemists to continue the exploration and to apply the chemistry for the benefit of mankind. 

The study of gas phase reactions between ions and neutral species is an application of mass spectrometry to organozinc chemistry with only partially explored potential. These experiments could be useful for the understanding of mechanisms of selected reactions as well as for the structural characterization of unstable intermediates. 

To comprehend the value of fundamental scientific work one must look back and weave the strands together. Sometimes the threads are very evident. For example, the battle of Britain was won in considerable part by the use of planes which were products of combustion research. The interrelationships of supercharging, compression, and fuel properties and composition in the reciprocating engine had been partially explored at that time. The Germans seemed to apply these principles but slowly at first. The British put this knowledge to work immediately as did the petroleum industry in the United States in those frantic days of producing tremendous quantities of fuel. 

In regard to third-party collaboration in the manufacture of Schering-Plough s antibiotic, Florfenicol (XVII), the initial thrust by our Animal Health Division, developers of the molecule, was to involve a third party with an excellent track record in another project with them. The third party partially explored the synthesis outlined in Scheme 6. 

The relative importance of these assumptions and the effects of introducing changes during accretion have been partially explored in several studies (HaUiday et ai, 1996, 2000 Halliday and Lee, 1999 Halliday, 2000). The issue of metal-silicate equilibration has been investigated recently by Yoshino et al. (2003). However, the data upon which many of the fundamental isotopic and chemical parameters are based are in a state of considerable uncertainty. 

It was thus early recognized that structural deformations of double bonds are related to instability and enhanced reactivity. It is this relationship that induced extensive studies of strained carbon compounds and distorted olefins. Moreover, it is evident that even today, the inherent chemical information potential of strained olefins has only been partially explored (4-6). 

When we progress from the foregoing qualitative discussion of structure-property relationships to the quantitative specification of mechanical properties, we enter a jungle that has been only partially explored. The most convenient point of departure into this large and complex subject is provided by the topic of "linear viscoelasticity." Linear viscoelasticity represents a relatively simple extension of classical (small-strain) theory of elasticity. In situations where linear viscoelasticity applies, the mechanical properties can be determined from a few experiments and can be specified in any of several equivalent formulations (11). 

Major questions remain. Much, but possibly not all, of this synthesis occurs in the Golgi apparatus, but transglycosylations might well take place in the wall itself. Nothing is known of initiation and priming mechanisms in any part of pectin assembly, or of any requirements there may be for lipid-linked intermediates. The control of precursor pool sizes and the relative importance of the cyclitol pathway have been only partially explored. Pectin still has much to offer the biochemist. 

Validating the correctness of systems by generating the corresponding state space (SSp) is a common method limited by the possible exponential growth of its size, known as the SSp explosion problem. Probabilistic methods focus on analyzing just a fraction of the SSp by means of partial exploration, but the probability of omitting states is greater than zero, sometimes incorrect evaluations are bound to happen and conclusiveness is not achievable all the time. 

Our research is to determine the existence of certain states without having to explore the entire SSp. This is done with a reachability analysis, by using a partial exploration algorithm. 

In the confines of reachability analysis in SSp generated from Petri net (PN) systems, there is a large list of works doing partial exploration [1, 5, 6, 11]. Although good results exist for some specific cases, others lack conclusiveness due to unsuccessful search [7, 8, 10]. 

The output of any partial exploration can be seen as a probabilistic sample. Upon unsuccessful search, a hypothesis test can be conducted for completeness using the sample. In general, random walk is used in the partial exploration algorithm, but random walk cannot be used as a sampling method because the probability that a given state is visited is far from being uniform [13]. Therefore, the sample is biased and any posterior hypothesis test will be incorrect. 

In this chapter first we show how to obtain a sample during the partial exploration of the SSp which is utilizable in any posterior hypothesis test, and second we explain how to give conclusiveness to the reachability analysis in the case of unsuccessful search by means of a h) thesis test. 

This chapter presents a partial exploration algorithm guided by a quota sampling. It is basically a table of quotas to fill in during the exploration. The sampling method is neither totally unbiased nor valid variance estimate, but it goes in the direction toward obtaining a representative sample. Then, we show a proper treatment to the sample by means of a hypothesis test [10] to provide conclusiveness to the analysis. 

One analysis strategy for the state space (SSp) is exploration. The exploration can be complete and partial. A major difficulty in the partial exploration is to conduct a random search with proper length and simultaneously traversing it all. 

Partial Exploration of State Spaces and Hypothesis Test for Unsuccessful Search 3... 

Non-probabilistic sampling methods appeal more to notions of representativity [14]. In this section we explain how to get a representative sample of the SSp according to the variable Y which is assumed to be normally distributed. The sample is obtained with a partial exploration algorithm guided by a quota sampling [14]. 

In our reachability analysis, in searching a target marking m, with cardinality of c, the partial exploration algorithm fills in the quota of samples for a table of n markings from the SSp. 

Jimenez SE (2011) Hypothesis test for unsuccessful partial explorations of state spaces of Petri nets, hi Proceedings of world congress on engineering (WCE 2011). Lecture Notes in Engineering and Computer Science. London, UK, 6-8 July 2011, pp 1254-1259... 

Development of remotely operated vehicles, greatly expanded since the 1980 s, has made it possible to penetrate ocean depths that were unreachable by manned undersea devices. In May, 2009, the Woods Hole Oceanographic Institution used a remotely operated vehicle called the Nereus to revisit the depths of the Mariana Trench, which had been partially explored by a Japanese remotely operated vehicle in 1998. The small dimensions of the Nereus (8 feet wide and 14 feet long) enabled it to maneuver in tight spaces, and the vehicle combined several advanced technologies, most notably a remarkably thin fiber-optic tether. 

The 1953 discovery of DNA opened a previously inconceivable window on a new biology horizon, so vast that it is not yet even partially explored ... 

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