Oligonucleotides containing a 3'-thiothymidine residue (T3's) at the cleavage site for the EcoRV restriction endonuclease (between the central T and A residues of the sequence GATATC) have been prepared on an automated DNA synthesizer using 5'-O-monomethoxytritylthymidine 3'-S-(2-cyanoethyl N,N-diisopropylphosphorothioamidite). The self-complementary sequence GACGAT3'sATCGTC was completely resistant to cleavage by EcoRV, while the heteroduplex composed of 5'-TCTGAT3'sATCCTC and 5'-GAGGATATCAGA (duplex 4) was cleaved only in the unmodified strand (5'-GAGGATATCAGA). In contrast, strands containing a 3'-S-phosphorothiolate linkage could be chemically cleaved specifically at this site with Ag+. A T3's residue has also been incorporated in the (-) strand of double-stranded closed circular (RF IV) M13mp18 DNA at the cleavage site of a unique EcoRV recognition sequence by using 5'-pCGAGCTCGAT3'sATCGTAAT as a primer for polymerization on the template (+) strand of M13mp18 DNA. On treatment of this substrate with EcoRV, only one strand was cleaved to produce the RF II or nicked DNA. Taken in conjunction with the cleavage studies on the oligonucleotides, this result demonstrates that the 3'-S-phosphorothiolate linkage is resistant to scission by EcoRV. Additionally, the phosphorothiolate-containing strand of the M13mp18 DNA could be cleaved specifically at the point of modification using iodine in aqueous pyridine. The combination of enzymatic and chemical techniques provides, for the first time, a demonstrated method for the sequence-specific cleavage of either the (+) or (-) strand.
The terms ‘capability’ and ‘capability engineering’ are now widely used across industry and in government procurement, but it is clear that different communities use the terms with similar, but distinctly different meanings. Using a soft systems methodological approach, an INCOSE UK working group has identified eight perspectives of capability, which have been related to Ring's value cycle and the Hitchins' five layer model of systems engineering. It is asserted that capability is the ability to do something and that capability engineering is the overarching approach that links value, purpose, and solution of a systems problem. It is equivalent to layers 1–4 of Hitchins' Five Layer Model and is equivalent to an holistic perspective of systems engineering. There are significant practice and examples of capability engineering from (at least) the UK rail provision, defence, and Information Services and it is the view of the working group that further INCOSE guidance may be needed to ensure engineers are properly equipped to deal with capability and capability engineering.
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Abstract. The last 20 years have shown a dramatic expansion in Systems Engineering theory, knowledge, knowhow and practical application. Despite this increase, there is evidence within organisations that there has been a growing gap between the SE required and the SE delivered. The authors of this paper describe the results of a study into the reasons for this gap, based on an on-line survey which received 85 valid responses.The authors conclude that:• Project professionals are using approaches that are not appropriate to the problems being tackled; • Behaviour is being driven by narrow views of what organisations believe is right, rather than the broader range of practice that they allow; • Project professionals adopt preferred approaches which they apply across more than one type of problem.The authors demonstrate that there is truth in the assertion that Systems Engineers apply the same approach, irrespective of the situation. Whilst standard Systems Engineering approaches, for example the V lifecycle, are the right approach in the complicated space, it is less appropriate in simple, complex or chaotic spaces. All too often, projects start with the assumption that we should use standard Systems Engineering approaches that we have used before, rather than ask: 'To V or not to V?'
Lead systems engineer (Rail) 5 th Floor AbstractThe conventional systems engineering process (as defined in ISO 15288 or the INCOSE SE handbook) assumes that projects start with a defined requirement or problem statement and end with contract acceptance or in-service validation. This has led to a belief by some in industry that the role of systems engineers within client organisations is kicking-off and accepting well formed programmes for industry to deliver. Whilst this is an important role, it is not the only part of the client side systems engineer's job.This paper describes the activities that systems engineers do when working for the client such as government, a transport service company or an information services company. Far from just playing a peripheral role in product systems engineering, the client side systems engineer is involved in:• Capability systems engineering -identifying, developing and integrating systems and services to realise operational capability • Service systems engineering -integrating existing and newly delivered systems to deliver operational services • Enterprise systems engineering -redesigning their organisations to improve organisational performance or reduce costs This paper describes these different systems engineering disciplines and draws comparisons between the types of systems engineering needed to deliver capabilities, services and enterprises and the more familiar approaches needed to deliver products (included at Annex A). The paper examines the different tools, processes, people and relationships needed to undertake these different types of systems engineering, in particular comparing them to conventional product systems engineering. Additionally, the paper introduces a framework within which the different types of systems engineering can be evaluated.
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