A looped-functional approach for robust stability analysis of linear impulsive systems

A new functional-based approach is developed for the stability analysis of linear impulsive systems. The new method, which introduces looped-functionals, considers non-monotonic Lyapunov functions and leads to LMIs conditions devoid of exponential terms. This allows one to easily formulate dwell-times results, for both certain and uncertain systems. It is also shown that this approach may be applied to a wider class of impulsive systems than existing methods. Some examples, notably on sampled-data systems, illustrate the efficiency of the approach.Comment: 13 pages, 2 figures, Accepted at Systems & Control Letter

Analytical evaluation of the impact of broad specification fuels on high bypass turbofan engine combustors

The impact of the use of broad specification fuels on the design, performance durability, emissions and operational characteristics of combustors for commercial aircraft gas turbine engines was assessed. Single stage, vorbix and lean premixed prevaporized combustors, in the JT9D and an advanced energy efficient engine cycle were evaluated when operating on Jet A and ERBS (Experimental Referee Broad Specification) fuels. Design modifications, based on criteria evolved from a literature survey, were introduced and their effectiveness at offsetting projected deficiencies resulting from the use of ERBS was estimated. The results indicate that the use of a broad specification fuel such as ERBS, will necessitate significant technology improvements and redesign if deteriorated performance, durability and emissions are to be avoided. Higher radiant heat loads are projected to seriously compromise liner life while the reduced thermal stability of ERBS will require revisions to the engine-airframe fuel system to reduce the thermal stress on the fuel. Smoke and emissions output are projected to increase with the use of broad specification fuels. While the basic geometry of the single stage and vorbix combustors are compatible with the use of ERBS, extensive redesign of the front end of the lean premixed prevaporized burner will be required to achieve satisfactory operation and optimum emissions

Europe’s New Post-Trade Infrastructure Rules. ECMI Policy Brief No. 20, 8 November 2012

After more than a decade of indecision, the EU is finally now set to implement a consistent regulatory architecture for clearing and settlement. Following the agreement on a European market infrastructure Regulation (EMIR), the European Commission has proposed harmonised rules for centralised settlement depositaries (CSDs), while the European Central Bank is moving forward with its plans for a central eurozone settlement engine. This paper analyses three components of the new post-trade infrastructure measures: 1) the regulatory framework for and supervision of central counterparties under the new EMIR legislation, 2) the authorisation requirements of trade repositories and 3) the draft CSD Regulation and the progress with the ECB’s Target 2 Securities project. It then discusses the impact of the new rules, and argues that, analogous to the unexpected impact of MiFID on trading infrastructures, a similar EMIR revolution may be on its way

Analytical screening of low emissions, high performance duct burners for supersonic cruise aircraft engines

An analytical screening study was conducted to identify duct burner concepts capable of providing low emissions and high performance in advanced supersonic engines. Duct burner configurations ranging from current augmenter technology to advanced concepts such as premix-prevaporized burners were defined. Aerothermal and mechanical design studies provided the basis for screening these configurations using the criteria of emissions, performance, engine compatibility, cost, weight and relative risk. Technology levels derived from recently defined experimental low emissions main burners are required to achieve both low emissions and high performance goals. A configuration based on the Vorbix (Vortex burning and mixing) combustor concept was analytically determined to meet the performance goals and is consistent with the fan duct envelope of a variable cycle engine. The duct burner configuration has a moderate risk level compatible with the schedule of anticipated experimental programs

The Financial Crisis and the Regulation of Credit Rating Agencies : A European Banking Perspective

Credit rating agencies (CRAs) bear some responsibility for the financial crisis that started in 2007 and remains ongoing. This is acknowledged by policymakers, market participants, and by the agencies themselves. It soon became clear that, given the depth of the crisis, CRAs would not be able to satisfy policymakers by eliminating flaws in their rating methods and improving corporate governance. Although the CRAs were more or less unregulated before the outbreak of the financial crisis, after the crisis started, politicians became increasingly vocal in demanding regulation. Initially, these demands were confined to a more binding form of self-regulation. But as the crisis progressed, the calls for state regulation grew ever louder. It became apparent after the November 2008 G-20 summit in Washington that state regulation could no longer be avoided. In Europe, the course had been set in this direction even before then. Since European policymakers saw the crisis as evidence that the Anglo-Saxon approach to the financial markets had failed, they believed they were now strongly placed to have a decisive influence on shaping a new international financial order. It is remarkable to note the shift in European policy from a self-regulatory approach, which was comparatively liberal in international terms, to quite rigorous state regulation of CRAs. Both the European Commission and the European Parliament drew up far-reaching plans. Although European policymakers knew that only globally consistent regulation would be appropriate for a new world financial order, their initial draft legislation was geared more toward stand-alone European regulation. While the final version of the European Union Regulation on Credit Rating Agencies focuses firmly on the European arena, the key point for all market participants is that this is unlikely to have an adverse effect on the global ratings market. It must nevertheless be recognized that the scope of the selected regulatory approach is extremely narrow. Certainly, it has the potential to improve the corporate governance of CRAs and prevent conflicts of interests. But it can do nothing to address the repeated calls for greater competition or for CRAs to be made liable for their ratings.credit rating agencies, financial crisis, financial regulation, European Regulation