An Axiomatic Approach to Liveness for Differential Equations

This paper presents an approach for deductive liveness verification for ordinary differential equations (ODEs) with differential dynamic logic. Numerous subtleties complicate the generalization of well-known discrete liveness verification techniques, such as loop variants, to the continuous setting. For example, ODE solutions may blow up in finite time or their progress towards the goal may converge to zero. Our approach handles these subtleties by successively refining ODE liveness properties using ODE invariance properties which have a well-understood deductive proof theory. This approach is widely applicable: we survey several liveness arguments in the literature and derive them all as special instances of our axiomatic refinement approach. We also correct several soundness errors in the surveyed arguments, which further highlights the subtlety of ODE liveness reasoning and the utility of our deductive approach. The library of common refinement steps identified through our approach enables both the sound development and justification of new ODE liveness proof rules from our axioms.Comment: FM 2019: 23rd International Symposium on Formal Methods, Porto, Portugal, October 9-11, 201

The EU-South Korea Free Trade Agreement and Its Implications for the United States

[Excerpt] On October 6,2010, the 27 member European Union (EU) and South Korea signed a bilateral free trade agreement (FTA). The agreement is expected to go into effect on July 1, 2011, pending approval by the European Parliament and the South Korean National Assembly. If enacted, the South Korea-EU FTA (KOREU FTA) would be the largest FTA in terms of market size that South Korea has entered into. The KOREU FTA reflects the EU and South Korean trade strategies to use FTAs to strengthen economic ties outside their home regions. It also builds upon the surge in trade and investment flows between South Korea and the EU over the past decade. This agreement has possible implications for U.S. trade with South Korea and congressional action on the proposed U.S.-South Korea FTA (KORUS FTA). The proposed KOREU FTA is very comprehensive. It would reduce and eliminate tariffs and other trade barriers in manufactured goods, agricultural products and services and would also cover such trade-related activities as government procurement, intellectual property rights, labor rights and environmental issues. Most studies done on the potential impact of the KOREU FTA estimate that the agreement will have a small but positive effect on the economies of the EU and South Korea as a whole and that the larger relative impact would be on the South Korean economy. The greatest economic impact of the KOREU FTA would be on specific sectors in each economy. EU services providers would be expected to experience gains from the agreement, especially in the areas of retail and wholesale trade, transportation services, financial services, and business services. In terms of trade in goods, EU exporters of pharmaceuticals, auto parts, industrial machinery, electronics parts, and some agricultural goods and processed foods would be expected to gain from the KOREU FTA\u27s implementation. At the same time, South Korean manufacturers of cars, ships, wireless telecommunications devices, chemical products, and imaging equipment would be expected to increase their exports to the EU market. The KOREU FTA is similar to the proposed KORUS FTA in many respects. Both agreements are comprehensive and both would eliminate tariffs on most trade in goods soon after they enter into force. However, they differ in other respects. Phase-out periods for tariffs on some manufactured goods differ. In addition, the KOREU FTA does not cover foreign direct investment. Unlike the KORUS FTA, the KOREU FTA would not allow trade sanctions to be applied where violations of the workers\u27 rights, and environment provisions have been deemed to occur. In addition, the KORUS FTA would cover a broader range of trade in services than would the KOREU FTA. It is not clear whether these differences in the structures of the FTAs would result in appreciable differences in outcomes in terms of economic gains and losses. U.S. and European firms are close competitors in a number of sectors and industries, particularly autos. Some business representatives argue that enactment of the KOREU FTA before enactment of the KORUS FTA would give European competitors commercial first mover advantages, since EU firms, such as those in the auto industry or the services sector, could gain greater market opportunities in South Korea not afforded to US. firms. On the other hand, other factors could also mitigate such advantages. For example, U.S. multinational firms operating in the EU could benefit from the KOREU FTA. Nevertheless, the content and fate of the KOREU FTA could influence the pace and tone of any debate in the United States on the KORUS FTA in the 112th Congress

The Proposed U.S.-South Korea Free Trade Agreement (KORUS FTA): Provisions and Implications

[Excerpt] On June 30, 2007, U.S. and South Korean trade officials signed the proposed U.S.-South Korean Free Trade Agreement (KORUS FTA) for their respective countries. If approved, the KORUS FTA would be the second-largest FTA that South Korea has signed to date, after the agreement with the European Union (EU). It would be the second-largest (next to North American Free Trade Agreement, NAFTA) in which the United States participates. South Korea is the seventhlargest trading partner of the United States and the United States is South Korea’s third-largest trading partner. Various studies conclude that the agreement would increase bilateral trade and investment flows. The final text of the proposed KORUS FTA covers a wide range of trade and investment issues and, therefore, could have substantial economic implications for both the United States and South Korea. The agreement will not enter into force unless Congress approves implementation legislation. The negotiations were conducted under the trade promotion authority (TPA), also called fast-track trade authority, that Congress granted the President under the Bipartisan Trade Promotion Act of 2002 (P.L. 107-210). Under TPA the President has the discretion on when to submit the implementing legislation to Congress. President Bush did not submit the legislation because of differences with the Democratic leadership over treatment of autos and beef, among other issues. Early in his Administration, President Obama indicated the need to resolve those issues before he would submit the implementing legislation. On December 3, 2010, after a series of arduous negotiations and missed deadlines, President Obama and President Lee announced that their negotiators reached agreement on modifications in the KORUS FTA, and that they were prepared to move ahead to getting the agreement approved by the respective legislatures. The White House is expected to send implementing legislation to the 112th Congress and that it would like to see Congress approve the agreement by July 1 of this year. The modifications are in the form of changes in phase-out periods for tariffs on autos, a new safeguard provision on autos, and concessions by South Korea on allowing a larger number of U.S. cars into South Korea under U.S. safety standards than was the case under the original KORUS FTA provisions. The issue of full U.S. beef access was not resolved because of the political sensitivity of the issue in South Korea. In 2008, when President Lee reached a separate agreement with the United States to lift South Korea’s ban on U.S. beef imports, massive anti-South Korean government protests forced the two governments to renegotiate its terms. The U.S. beef sector has largely supported the KORUS FTA. A broad swath of the U.S. business community supports the KORUS FTA . With the modifications in the agreement reached in December, this group also includes the three Detroit-based auto manufacturers and the United Auto Workers (UAW) union. It still faces opposition from some labor unions and other groups, including Public Citizen. Many U.S. supporters view passage of the KORUS FTA as important to secure new opportunities in the South Korean market, while opponents claim that the KORUS FTA does not go far enough to break down South Korean trade barriers or that the agreement will encourage U.S. companies to move their production offshore at the expense of U.S. workers. Other observers have suggested the outcome of the KORUS FTA could have implications for the U.S.-South Korean alliance as a whole, as well as on U.S. Asia policy and U.S. trade policy, particularly in light of an FTA signed in by South Korea and the EU that is expected to go into effect on July 1, 2011

Towards Physical Hybrid Systems

Some hybrid systems models are unsafe for mathematically correct but physically unrealistic reasons. For example, mathematical models can classify a system as being unsafe on a set that is too small to have physical importance. In particular, differences in measure zero sets in models of cyber-physical systems (CPS) have significant mathematical impact on the mathematical safety of these models even though differences on measure zero sets have no tangible physical effect in a real system. We develop the concept of "physical hybrid systems" (PHS) to help reunite mathematical models with physical reality. We modify a hybrid systems logic (differential temporal dynamic logic) by adding a first-class operator to elide distinctions on measure zero sets of time within CPS models. This approach facilitates modeling since it admits the verification of a wider class of models, including some physically realistic models that would otherwise be classified as mathematically unsafe. We also develop a proof calculus to help with the verification of PHS.Comment: CADE 201

Extending Hybrid CSP with Probability and Stochasticity

Probabilistic and stochastic behavior are omnipresent in computer controlled systems, in particular, so-called safety-critical hybrid systems, because of fundamental properties of nature, uncertain environments, or simplifications to overcome complexity. Tightly intertwining discrete, continuous and stochastic dynamics complicates modelling, analysis and verification of stochastic hybrid systems (SHSs). In the literature, this issue has been extensively investigated, but unfortunately it still remains challenging as no promising general solutions are available yet. In this paper, we give our effort by proposing a general compositional approach for modelling and verification of SHSs. First, we extend Hybrid CSP (HCSP), a very expressive and process algebra-like formal modeling language for hybrid systems, by introducing probability and stochasticity to model SHSs, which is called stochastic HCSP (SHCSP). To this end, ordinary differential equations (ODEs) are generalized by stochastic differential equations (SDEs) and non-deterministic choice is replaced by probabilistic choice. Then, we extend Hybrid Hoare Logic (HHL) to specify and reason about SHCSP processes. We demonstrate our approach by an example from real-world.Comment: The conference version of this paper is accepted by SETTA 201

Constructive Hybrid Games

Hybrid games are models which combine discrete, continuous, and adversarial dynamics. Game logic enables proving (classical) existence of winning strategies. We introduce constructive differential game logic (CdGL) for hybrid games, where proofs that a player can win the game correspond to computable winning strategies. This is the logical foundation for synthesis of correct control and monitoring code for safety-critical cyber-physical systems. Our contributions include novel static and dynamic semantics as well as soundness and consistency.Comment: 60 pages, preprint, under revie

The role of health determinants in the influenza vaccination uptake among older adults (65+): a scope review

Background: Although the burden of influenza infection is the highest in older adults, vaccination coverage remains low, despite this age group being more vulnerable than others. Aims: Given the current pandemic of SARS-CoV-2, it was the aim of this scope review to update knowledge on factors affecting seasonal influenza vaccine uptake among older adults to strengthen prevention approaches in the context of an overall burden of infectious diseases. Methods: We searched bibliographic databases from 2012 to 2019. All studies reviewed one or more social determinant of health listed by WHO, or factors affecting the decision-making process whether to accept influenza vaccine or not. Results: Overall, 44 studies were included, 41 determinants were extracted and summarized into six categories. Older age and constitutional factors including multiple chronic diseases as well as preventive lifestyle and frequent routine healthcare utilization positively affected vaccination uptake (VU). Living and working conditions are also researched determinants of influenza vaccine uptake. A small number of studies explored the role of social inclusion and system-based interventions. Discussion and conclusions: This scope review provides a comprehensive overview on factors affecting seasonal influenza vaccination uptake among older citizens. The review also clearly shows gaps for evidence on system-based level or political strategies to improve vaccination uptake

Labour Market and Social Policy in Italy: Challenges and Changes. Bertelsmann Policy Brief #2016/02

vEight years after the outbreak of the financial crisis, Italy has still to cope with and overcome a plethora of economic and social challenges. On top of this, it faces an unfavourable demographic structure and severe disparities between its northern and southern regions. Some promising reforms have recently been enacted, specifically targeting poverty and social exclusion. However, much more remains to be done on the way towards greater economic stability and widely shared prosperity