A public key cryptosystem based on block upper triangular matrices

We propose a public key cryptosystem based on block upper triangular matrices. This system is a variant of the Discrete Logarithm Problem with elements in a finite group, capable of increasing the difficulty of the problem while maintaining the key size. We also propose a key exchange protocol that guarantees that both parties share a secret element of this group and a digital signature scheme that provides data authenticity and integrity.

Quantitative stability of linear infinite inequality systems under block perturbations with applications to convex systems

The original motivation for this paper was to provide an efficient quantitative analysis of convex infinite (or semi-infinite) inequality systems whose decision variables run over general infinite-dimensional (resp. finite-dimensional) Banach spaces and that are indexed by an arbitrary fixed set J. Parameter perturbations on the right-hand side of the inequalities are required to be merely bounded, and thus the natural parameter space is l ∞(J). Our basic strategy consists of linearizing the parameterized convex system via splitting convex inequalities into linear ones by using the Fenchel–Legendre conjugate. This approach yields that arbitrary bounded right-hand side perturbations of the convex system turn on constant-by-blocks perturbations in the linearized system. Based on advanced variational analysis, we derive a precise formula for computing the exact Lipschitzian bound of the feasible solution map of block-perturbed linear systems, which involves only the system’s data, and then show that this exact bound agrees with the coderivative norm of the aforementioned mapping. In this way we extend to the convex setting the results of Cánovas et al. (SIAM J. Optim. 20, 1504–1526, 2009) developed for arbitrary perturbations with no block structure in the linear framework under the boundedness assumption on the system’s coefficients. The latter boundedness assumption is removed in this paper when the decision space is reflexive. The last section provides the aimed application to the convex case.

Comparison of Lattice-Fluid Binary Parameters For Mixtures and Block Copolymers

The aim of this report is to discuss the method of determination of lattice-fluid binary interaction parameters by comparing well characterized immiscible blends and block copolymers of poly(methyl methacrylate) (PMMA) and poly(ϵ−caprolactone) (PCL). Experimental pressure-volume-temperature (PVT) data in the liquid state were correlated with the Sanchez—Lacombe (SL) equation of state with the scaling parameters for mixtures and copolymers obtained through combination rules of the characteristic parameters for the pure homopolymers. The lattice-fluid binary parameters for energy and volume were higher than those of block copolymers implying that the copolymers were more compatible due to the chemical links between the blocks. Therefore, a common parameter cannot account for both homopolymer blend and block copolymer phase behaviors based on current theory. As we were able to adjust all data of the mixtures with a single set of lattice-binary parameters and all data of the block copolymers with another single set we can conclude that both parameters did not depend on the composition for this system. This characteristic, plus the fact that the additivity law of specific volumes can be suitably applied for this system, allowed us to model the behavior of the immiscible blend with the SL equation of state. In addition, a discussion on the relationship between lattice-fluid binary parameters and the Flory–Huggins interaction parameter obtained from Leibler's theory is presented.

Freedom of movement of persons - the building block of European growth. CHALLENGE EUROPE Issue 22 - Challenges and new beginnings: Priorities for the EU's new leadership, September 2014.

The European integration project is founded on values and principles which are simple, equal, and advantageous for all. Freedom of movement of persons is one of the main cornerstones of EU success. It is a fundamental, cherished right of EU citizens. Thanks to this liberty, European citizenship is real, concrete and attractive. Moreover, it spurs economic growth and technological development. But because freedom of movement has become an obvious feature of our day-to-day lives, some of us tend to underestimate its consequences. Important recent developments mean that we must renew our commitment to defend this building-block of a Europe whole and free.

Could Transnistria block Moldova's integration with the EU? OSW Commentary No. 95, 2012-10-23

Moldova’s progress in its negotiations on an Association Agreement with the European Union, with a Deep and Comprehensive Free Trade Area (DCFTA) as its key element, has become a source of tension between Chisinau and the breakaway Republic of Transnistria. An almost certain refusal by Transnistria to join the DCFTA, will deprive the region of the benefits it currently enjoys under the EU Autonomous Trade Preferences (ATP) worsening its already precarious economic situation. It is to be expected that the issue will become an additional source of tension between the two sides of the Transnistrian conflict, and might also have a negative impact on the EU–Russia relationship. The signing of the Association Agreement, which is scheduled for the autumn of 2013, will be an important step towards Moldova’s integration with the EU. Both sides assign great importance to the speediest possible finalisation of the Agreement, and so far the negotiations have been described as progressing very smoothly. Transnistria’s highly sceptical attitude towards its possible accession to the DCFTA, however, is consistent with the interests of its main ally, Moscow. It is highly probable that Russia intends to thwart Moldova’s EU association process. Moscow’s objective seems to be to draw Moldova permanently into its own sphere of influence, and therefore it perceives Chisinau’s movement towards the EU as a transgression against its geopolitical interests. Consequently, in order to hinder this process, Russia may instrumentally exploit its extensive influence over Transnistria to provoke a crisis between Tiraspol and Chisinau. An apparent increase in Russian presence in the region over the last few months (including tighter control over Transnistria’s KGB and the Ministry of Information) may suggest that the Kremlin is preparing to implement such a scenario.

Heads buried in the sand: member states block solutions to the refugee crisis. EPC Commentary, 15 September 2015

Yesterday’s meeting of Interior Ministers demonstrated that the EU’s asylum and immigration policy remains incomplete. This is mainly due to the member states’ inability to plan ahead, their reluctance to adopt binding common rules – considered as a violation of their sovereignty – and their central position in the implementation of EU rules.

spotlight europe #2015/04—October 2015: A Fiscal Union for Europe – Building Block and Not a Magic Bullet

The dramatic negotiations with Greece in the past few months have been a telling reminder of the weaknesses of the euro area. Most of the commentators are of the opinion that if the monetary union is going to be crisis-resistant and stable in the long term, certain very important elements will have to be changed. However, there is little or no agreement when it comes to specifying the "what" and the "how". In particular there are heated debates about the right steps to further integration in the area of fiscal policy. "Fiscal union can create stability only if it includes both credible budgetary rules and some kind of risk sharing", argue Katharina Gnath and Jörg Haas in the latest spotlight europe. However, "whilst it is an important and effective way of stabilizing the euro area, it should not exclude the use of other instruments."

Hangsterfer Block in 1862 or 1867 at 316 South State St., Ann Arbor, Mich.

Former site of Kresge's. Source: Ray Hutzel

Left: Livery & Sale Stables, J.A. Polhemus & Son, Proprs., Ann Arbor, Mich. Left: Buchoz's Block, Ann Arbor, Mich. Bottom: Orchestrian Hall, Fred Rettich, Proprietor, Ann Arbor, Mich.

Ann Arbor, Mich. businesses. Publication information: Chicago, Ill. : Everts & Stewart, 1874.