Specification and Verification of Commitment-Regulated Data-Aware Multiagent Systems

In this paper we investigate multi agent systems whose agent interaction is based on social commitments that evolve over time, in presence of (possibly incomplete) data. In particular, we are interested in modeling and verifying how data maintained by the agents impact on the dynamics of such systems, and on the evolution of their commitments. This requires to lift the commitment-related conditions studied in the literature, which are typically based on propositional logics, to a first-order setting. To this purpose, we propose a rich framework for modeling data-aware commitment-based multiagent systems. In this framework, we study verification of rich temporal properties, establishing its decidability under the condition of “state-boundedness”, i.e., data items come from an infinite domain but, at every time point, each agent can store only a bounded number of them

Modeling and Verifying Probabilistic Social Commitments in Multi-Agent Systems

Interaction among autonomous agents in Multi-Agent Systems (MASs) is the key aspect for solving complex problems that an individual agent cannot handle alone. In this context, social approaches, as opposed to the mental approaches, have recently received a considerable attention in the area of agent communication. They exploit observable social commitments to develop a verifiable formal semantics by which communication protocols can be specified. However, existing approaches for defining social commitments tend to assume an absolute guarantee of correctness so that systems run in a certain manner. That is, social commitments have always been modeled with the assumption of certainty. Moreover, the widespread use of MASs increases the interest to explore the interactions between different aspects of the participating agents such as the interaction between agents’ knowledge and social commitments in the presence of uncertainty. This results in having a gap, in the literature of agent communication, on modeling and verifying social commitments in probabilistic settings. In this thesis, we aim to address the above-mentioned problems by presenting a practical formal framework that is capable of handling the problem of uncertainty in social commitments. First, we develop an approach for representing, reasoning about, and verifying probabilistic social commitments in MASs. This includes defining a new logic called the probabilistic logic of commitments (PCTLC), and a reduction-based model checking procedure for verifying the proposed logic. In the reduction technique, the problem of model checking PCTLC is transformed into the problem of model checking PCTL so that the use of the PRISM (Probabilistic Symbolic Model Checker) is made possible. Formulae of PCTLC are interpreted over an extended version of the probabilistic interpreted systems formalism. Second, we extend the work we proposed for probabilistic social commitments to be able to capture and verify the interactions between knowledge and commitments. Properties representing the interactions between the two aspects are expressed in a new developed logic called the probabilistic logic of knowledge and commitment (PCTLkc). Third, we develop an adequate semantics for the group social commitments, for the first time in the literature, and integrate it into the framework. We then introduce an improved version of PCTLkc and extend it with operators for the group knowledge and group social commitments. The new refined logic is called PCTLkc+. In each of the latter stages, we respectively develop a new version of the probabilistic interpreted systems over which the presented logic is interpreted, and introduce a new reduction-based verification technique to verify the proposed logic. To evaluate our proposed work, we implement the proposed verification techniques on top of the PRISM model checker and apply them on several case studies. The results demonstrate the usefulness and effectiveness of our proposed work

Model Checking Logics of Social Commitments for Agent Communication

This thesis is about specifying and verifying communications among autonomous and possibly heterogeneous agents, which are the key principle for constructing effective open multi-agent systems (MASs). Effective systems are those that successfully achieve applicability, feasibility, error-freeness and balance between expressiveness and verification efficiency aspects. Over the last two decades, the MAS community has advocated social commitments, which successfully provide a powerful representation for modeling communications in the figure of business contracts from one agent to another. While modeling communications using commitments provides a fundamental basis for capturing flexible communications and helps address the challenge of ensuring compliance with specifications, the designers and business process modelers of the system as a whole cannot guarantee that an agent complies with its commitments as supposed to or at least not wantonly violate or cancel them. They may still wish to first formulate the notion of commitment-based protocols that regulate communications among agents and then establish formal verification (e.g., model checking) by which compliance verification in those protocols is possible. In this thesis, we address the aforementioned challenges by firstly developing a new branching-time temporal logic---called ACTL*c---that extends CTL* with modal operators for representing and reasoning about commitments and all associated actions. The proposed semantics for ACL (agent communication language) messages in terms of commitments and their actions is formal, declarative, meaningful, verifiable and semi-computationally grounded. We use ACTL*c to derive a new specification language of commitment-based protocols, which is expressive and suitable for model checking. We introduce a reduction method to formally transform the problem of model checking ACTL*c to the problem of model checking GCTL* so that the use of the CWB-NC model checker is possible. We prove the soundness of our reduction method and implement it on top of CWB-NC. To check the effectiveness of our reduction method, we report the verification results of the NetBill protocol and Contract Net protocol against some properties. In addition to the reduction method, we develop a new symbolic algorithm to perform model checking ACTL*c. To balance between expressiveness and verification efficiency, we secondly adopt a refined fragment of ACTL*c, called CTLC, an extension of CTL with modalities for commitments and their fulfillment. We extend the formalism of interpreted systems introduced to develop MASs with shared and unshared variables and considered agents' local states in the definition of a full-computationally grounded semantics for ACL messages using commitments. We present reasonable axioms of commitment and fulfillment modalities. In our verification technique, the problem of model checking CTLC is reduced into the problems of model checking ARCTL and GCTL* so that respectively extended NuSMV and CWB-NC (as a benchmark) are usable. We prove the soundness of our reduction methods and then implement them on top of the extended NuSMV and CWB-NC model checkers. To evaluate the effectiveness of our reduction methods, we verified the correctness of two business case studies. We finally proceed to develop a new symbolic model checking algorithm to directly verify commitments and their fulfillment and commitment-based protocols. We analyze the time complexity of CTLC model checking for explicit models and its space complexity for concurrent programs that provide compact representations. We prove that although CTLC extends CTL, their model checking algorithms still have the same time complexity for explicit models, and the same space complexity for concurrent programs. We fully implement the proposed algorithm on top of MCMAS, a model checker for the verification of MASs, and then check its efficiency and scalability using an industrial case study

DR-CAFTA and Worker’s Rights: Moving from Paper to Practice

This study analyses the “White Paper” projects and initiatives taken by the US government to improve labor rights practice in DR-CAFTA countries. Based on a three year study, WOLA has concluded that U.S. funding for projects to strengthen the enjoyment and enforcement of labor rights in the DR-CAFTA countries is insufficient to address institutional weakness and pervasive impunity. In this report WOLA defines labor law reforms needed in the six participating countries and recommends implementation methods

Global governance approaches to addressing illegal logging: Uptake and lessons learned

One of the most challenging tasks facing development agencies, trade ministries, environmental groups, social activists and forest-focused business interests seeking to ameliorate illegal logging and related timber trade is to identify and nurture promising global governance interventions capable of helping improve compliance to governmental policies and laws at national, subnational and local levels. This question is especially acute for developing countries constrained by capacity challenges and “weak states” (Risse, 2011). This chapter seeks to shed light on this task by asking four related questions: How do we understand the emergence of illegal logging as a matter of global interest? What are the types of global interventions designed to improve domestic legal compliance? How have individual states responded to these global efforts? What are the prospects for future impacts and evolution? We proceed in the following steps. Following this introduction, step two reviews how the problem of “illegal logging” emerged on the international agenda. Step three reviews leading policy interventions that resulted from this policy framing. Step four reviews developments in selected countries/regions around the world according to their place on the global forest products supply chain: consumers (United States, Europe and Australia); middle of supply chain manufacturers (China and South Korea) and producers (Russia; Indonesia; Brazil and Peru; Ghana, Cameroon and the Republic of Congo). We conclude by reflecting on key trends that emerge from this review relevant for understanding the conditions through which legality might make a difference in addressing critical challenges

Progress in Implementing Capacity-Building Provisions under the Labor Chapter of the Dominican Republic-Central America-United States Free Trade Agreement

The report provides relevant background on the CAFTA-DR. It describes the efforts of the CAFTA-DR countries to identify areas for improvement of labor standards, make additional reforms to their labor laws, and develop strategies for continued capacity-building and improvement

Progress in Implementing Capacity-Building Provisions under the Labor Chapter of the Dominican Republic – Central America – United States Free Trade Agreement

[Excerpt] Section 403(a) of the CAFTA-DR Implementation Act includes a reporting requirement on labor issues related to the CAFTA-DR. Specifically, that section requires the President to submit a biennial report to Congress on the progress made by the CAFTA-DR countries in implementing (i) Chapter Sixteen (Labor) of the CAFTA-DR, and (ii) the White Paper. The President delegated this reporting function to the Secretary of Labor, to be carried out in consultation with the United States Trade Representative (USTR). This is the first report in fulfillment of Section 403(a) of the CAFTA-DR Implementation Act. As required, this report includes: A. A description of the progress made by the Labor Cooperation and Capacity Building Mechanism established by Article 16.5 and Annex 16.5 of the CAFTA-DR, and the Labor Affairs Council established by Article 16.4 of the CAFTA-DR, in achieving their stated goals, including a description of the capacity-building projects undertaken, funds received, and results achieved, in each CAFTA-DR country; B. Recommendations on how the United States can facilitate full implementation of the recommendations contained in the White Paper; C. A description of the work done by the CAFTA-DR countries with the International Labor Organization (ILO) to implement the White Paper recommendations and to advance common commitments regarding labor matters; and D. A summary of public comments received on these matters

Progress in Implementing Capacity-Building Provisions under the Labor Chapter of the Dominican Republic – Central America – United States Free Trade Agreement

[Excerpt] Section 403(a) of the CAFTA-DR Implementation Act includes a reporting requirement on labor issues related to the CAFTA-DR. Specifically, that section requires the President to submit a biennial report to Congress on the progress made by the CAFTA-DR countries in implementing (i) Chapter Sixteen (Labor) of the CAFTA-DR, and (ii) the White Paper. The President delegated this reporting function to the Secretary of Labor, to be carried out in consultation with the United States Trade Representative (USTR). This is the first report in fulfillment of Section 403(a) of the CAFTA-DR Implementation Act. As required, this report includes: A. A description of the progress made by the Labor Cooperation and Capacity Building Mechanism established by Article 16.5 and Annex 16.5 of the CAFTA-DR, and the Labor Affairs Council established by Article 16.4 of the CAFTA-DR, in achieving their stated goals, including a description of the capacity-building projects undertaken, funds received, and results achieved, in each CAFTA-DR country; B. Recommendations on how the United States can facilitate full implementation of the recommendations contained in the White Paper; C. A description of the work done by the CAFTA-DR countries with the International Labor Organization (ILO) to implement the White Paper recommendations and to advance common commitments regarding labor matters; and D. A summary of public comments received on these matters

October 2006 - Report on Cocoa and Forced Child Labor

This document is part of a digital collection provided by the Martin P. Catherwood Library, ILR School, Cornell University, pertaining to the effects of globalization on the workplace worldwide. Special emphasis is placed on labor rights, working conditions, labor market changes, and union organizing.ILRF_ReportOnCocoaAndForcedChildLabor_2006.pdf: 257 downloads, before Oct. 1, 2020