Matching with Commitments

We consider the following stochastic optimization problem first introduced by Chen et al. in \cite{chen}. We are given a vertex set of a random graph where each possible edge is present with probability p_e. We do not know which edges are actually present unless we scan/probe an edge. However whenever we probe an edge and find it to be present, we are constrained to picking the edge and both its end points are deleted from the graph. We wish to find the maximum matching in this model. We compare our results against the optimal omniscient algorithm that knows the edges of the graph and present a 0.573 factor algorithm using a novel sampling technique. We also prove that no algorithm can attain a factor better than 0.898 in this model

Did the Kyoto Protocol fail? An evaluation of the effect of the Kyoto Protocol on CO2 emissions

In this paper, we empirically investigate the impact of the Kyoto Protocol on CO2 emissions using a sample of 170 countries over the period 1992-2009. We propose the use of a difference-in-differences estimator with matching to address the endogeneity of the policy variable, namely Kyoto commitments. Countries are matched according to observable characteristics to create a suitable counterfactual. We correspondingly estimate a panel data model for the whole sample and the matched sample and compare the results to those obtained using an instrumental variable approach. The main results indicate that Kyoto Protocol commitments have a measurable reducing effect on CO2 emissions, indicating that a treaty often deemed a 'failure' may in fact be producing some non-negligible effects for those who signed it

Access and benefit sharing policies for climate resilient seed systems: matching global commitments with national realities.

This synthesis paper provides a summary of main findings on climate resilient seed systems and access and benefit sharing of case studies from Uganda, Rwanda, Zambia and Zimbabwe. This study analyses what is actually happening at the national and subnational levels in terms of climate change, its impacts on particular crops, what experiences countries have had to date in terms of accessing, using and sharing benefits derived from genetic resources for climate change adaptation, and what kinds of ABS policy initiatives or reforms could help those countries to make better use of genetic diversity for climate change adaptation in the future. This study is designed to analyze how these different ‘threads’ come together at national and subnational level in the four countries. Findings from these studies indicate that countries are already facing climate change which is affecting farmers and shaping their needs in terms of suitably adapted seed. As a result, the countries are embracing (inter and intra specific) crop diversification as a means to adapt to climate changes. This depends upon accessibility, availability and use of inter and intra specific crop genetic diversity from local, national and international sources. The proportion of PGRFA in the countries’ national genebanks that is potentially adaptable to that country’s changing climate is decreasing over time (as climates change more). National level research and the development of new varieties is also not sufficient to meet these demands. Countries are therefore becoming more interdependent. There are also significant constraints on ability to access, use and share benefits associated with materials in other countries as a result of the lack of on-line accession level documentation (and linked implementation of ITPGRFA and Nagoya Protocol) and lack of proper polices, legislation and guidelines on ABS. The study therefore recommends that international partnerships and programmes are important mechanisms for the exchanges of genetic resources into and out of the four countries for agricultural research and development especially at regional level and that the ITPGRFA and Nagoya Protocol are not self-executing agreements but need to be proactively implemented. In addition, considerable investment in capacity building is necessary for stakeholders – including farmers – to be able to exchange genetic resources in a way that makes seed systems more resilient

Institutions, Information, and Trade Policy in Times of Crisis

The paper examines the role of international institutions in preventing the rise of protectionism in times of times of crisis. Economic crisis exacerbates uncertainty in the conduct of commercial relations and thus makes it more likely for countries to resort to "beggar-thy-neighbor" trade policies. The historical record of the Great Depression supports this argument, where global trade suffered a downward spiral as governments pursued protectionist trade policies as a response to domestic pressures. This paper argues that the current era of globalization is distinguishable from its earlier counterparts by the presence of an extensive network of international institutions, which serve as conveyors of information that help to mitigate the information problem that prevails in prisoner‘s dilemma settings. Specifically, international institutions such as the WTO, preferential trade agreements (PTAs) and other international economic organizations increase the flow of information among countries. In doing so, they alleviate coordination problems as well as facilitate the detection of violations in commitments to maintaining a liberal trade regime. We suggest that this mechanism may explain why the current crisis is not replicating the pattern of the Great Depression. Moreover, we explore the combined effect of membership in international organization and political variables, the latter including democracy, veto players, partisanship of government, and government effectiveness. We test this argument using a newly-compiled dataset of trade policies during the current economic crisis and membership in international organizations. The paper finds strong support for the informational role of international institutions as a key factor preventing the rise of protectionism in times of crisis. Conversely, there is mixed evidence that the combining effect of international organizations and domestic political variables matters in explaining protectionism during this crisis

Security and Efficiency Analysis of the Hamming Distance Computation Protocol Based on Oblivious Transfer

open access articleBringer et al. proposed two cryptographic protocols for the computation of Hamming distance. Their first scheme uses Oblivious Transfer and provides security in the semi-honest model. The other scheme uses Committed Oblivious Transfer and is claimed to provide full security in the malicious case. The proposed protocols have direct implications to biometric authentication schemes between a prover and a verifier where the verifier has biometric data of the users in plain form. In this paper, we show that their protocol is not actually fully secure against malicious adversaries. More precisely, our attack breaks the soundness property of their protocol where a malicious user can compute a Hamming distance which is different from the actual value. For biometric authentication systems, this attack allows a malicious adversary to pass the authentication without knowledge of the honest user's input with at most $O(n)$ complexity instead of $O(2^n)$, where $n$ is the input length. We propose an enhanced version of their protocol where this attack is eliminated. The security of our modified protocol is proven using the simulation-based paradigm. Furthermore, as for efficiency concerns, the modified protocol utilizes Verifiable Oblivious Transfer which does not require the commitments to outputs which improves its efficiency significantly

Effect of oil palm sustainability certification on deforestation and fire in Indonesia.

Many major corporations and countries have made commitments to purchase or produce only "sustainable" palm oil, a commodity responsible for substantial tropical forest loss. Sustainability certification is the tool most used to fulfill these procurement policies, and around 20% of global palm oil production was certified by the Roundtable on Sustainable Palm Oil (RSPO) in 2017. However, the effect of certification on deforestation in oil palm plantations remains unclear. Here, we use a comprehensive dataset of RSPO-certified and noncertified oil palm plantations (∼188,000 km2) in Indonesia, the leading producer of palm oil, as well as annual remotely sensed metrics of tree cover loss and fire occurrence, to evaluate the impact of certification on deforestation and fire from 2001 to 2015. While forest loss and fire continued after RSPO certification, certified palm oil was associated with reduced deforestation. Certification lowered deforestation by 33% from a counterfactual of 9.8 to 6.6% y-1 Nevertheless, most plantations contained little residual forest when they received certification. As a result, by 2015, certified areas held less than 1% of forests remaining within Indonesian oil palm plantations. Moreover, certification had no causal impact on forest loss in peatlands or active fire detection rates. Broader adoption of certification in forested regions, strict requirements to avoid all peat, and routine monitoring of clearly defined forest cover loss in certified and RSPO member-held plantations appear necessary if the RSPO is to yield conservation and climate benefits from reductions in tropical deforestation

Occupational Mobility and the Business Cycle

Do workers sort more randomly across different job types when jobs are harder to find? To answer this question, we study the mobility of male workers among three-digit occupations in the matched files of the monthly Current Population Survey over the 1979-2004 period. We clean individual occupational transitions using the algorithm proposed by Moscarini and Thomsson (2008). We then construct a synthetic panel comprising annual birth cohorts, and we examine the respective roles of three potential determinants of career mobility: individual ex ante worker characteristics, both observable and unobservable, labor market prospects, and ex post job matching. We provide strong evidence that high unemployment somewhat offsets the role of individual worker considerations in the choice of changing career. Occupational mobility declines with age, family commitments and education, but when unemployment is high these negative effects are weaker, and reversed for college education. The cross-sectional dispersion of the monthly series of residuals is strongly countercyclical. As predicted by Moscarini (2001)’s frictional Roy model, the sorting of workers across occupations is noisier when unemployment is high. As predicted by job-matching theory, worker mobility has significant residual persistence over time. Finally, younger cohorts, among those in the sample for most of their working lives, exhibit increasingly low unexplained career mobility.occupational mobility, business cycle, synthetic cohorts

"Explaining the September 1992 ERM Crisis: The Maastricht Bargain and Domestic Politics in Germany, France and Great Britain"

At the time of the September 1992 crisis, the conventional wisdom held in the ERM was due to an unfortunate contuence of exceptional circumstances -- the shock of German reunification, a debt-driven recession in Britain, and the uncertainties caused by the Danish and French referenda on Maastricht. This paper points to systemic factors at both the EC and domestic levels in explaining the September crisis. At the Community level, it is argued that the ERM was the victim of an underlying structural flaw in the Maastricht 3-stage plan for EMU. Intergovemmental bargaining, reflecting the differing national preferences of Germany and France in particular, produced an untenable compromise with potentially chaotic consequences: the matching of demanding economic convergence criteria with a strict timetable for their fulfillment, upon commencement of Stage II of the EMU process set for January 1994. Far from being epiphenomenal, this bargain was only the latest manifestation of an ongoing debate between "economist" and monetarist" approaches to monetary integration, tracing back to the early 1970s. and I argue that the "framing effects" of the Stage II criteria fundamentally altered the nature of economic discourse at Stage I, beginning in 1990. Specific reference numbers for debt ratios and relative and interest rate targets emphasized economic divergence in countries with clearly overvalued currencies, and invited markets to test the strength of govemments' political commitments to their exchange rate pegs. The second component of my explanation of the September crisis lies at the domestic level. Even though strict convergence criteria and timetables provided a severe test of the credibility of members' European commitments, it was not a foregone conclusion that the Maastricht bargain would result in turbulence on the currency markets. A margin of maneuver was left to the member governments, through the demonstration of a willingness to take painful measures, such as fiscal and wage restraint or timely interest rate hikes, to defend the ERM commitment

Encoding CSP into CCS

We study encodings from CSP into asynchronous CCS with name passing and matching, so in fact, the asynchronous pi-calculus. By doing so, we discuss two different ways to map the multi-way synchronisation mechanism of CSP into the two-way synchronisation mechanism of CCS. Both encodings satisfy the criteria of Gorla except for compositionality, as both use an additional top-level context. Following the work of Parrow and Sj\"odin, the first encoding uses a centralised coordinator and establishes a variant of weak bisimilarity between source terms and their translations. The second encoding is decentralised, and thus more efficient, but ensures only a form of coupled similarity between source terms and their translations.Comment: In Proceedings EXPRESS/SOS 2015, arXiv:1508.0634