Biblio

Traditionally, distributed computing concentrates on computation understood at the level of information exchange and sets aside human and organizational concerns as largely to be handled in an ad hoc manner.  Increasingly, however, distributed applications involve multiple loci of autonomy.  Research in multiagent systems (MAS) addresses autonomy by drawing on concepts and techniques from artificial intelligence.  However, MAS research generally lacks an adequate understanding of modern distributed computing.

In this Blue Sky paper, we envision decentralized multiagent systems as a way to place decentralized intelligence in distributed computing, specifically, by supporting computation at the level of social meanings.  We motivate our proposals for research in the context of the Internet of Things (IoT), which has become a major thrust in distributed computing.  From the IoT's representative applications, we abstract out the major challenges of relevance to decentralized intelligence.  These include the heterogeneity of IoT components; asynchronous and delay-tolerant communication and decoupled enactment; and multiple stakeholders with subtle requirements for governance, incorporating resource usage, cooperation, and privacy.  The IoT yields high-impact problems that require solutions that go beyond traditional ways of thinking.

We conclude with highlights of some possible research directions in decentralized MAS, including programming models; interaction-oriented software engineering; and what we term enlightened governance.

The notion of commitment is widely studied as a high-level abstraction for modeling multiagent interaction.  An important challenge is supporting flexible decentralized enactments of commitment specifications.  In this paper, we combine recent advances on specifying commitments and information protocols.  Specifically, we contribute Tosca, a technique for automatically synthesizing information protocols from commitment specifications. Our main result is that the synthesized protocols support commitment alignment, which is the idea that agents must make compatible inferences about their commitments despite decentralization.

Norms provide a way to model the social architecture of a sociotechnical system (STS) and are thus crucial for understanding how such a system supports secure collaboration between principals,that is, autonomous parties such as humans and organizations. Accordingly, an important challenge is to compute the state of a norm instance at runtime in a sociotechnical system.

Custard addresses this challenge by providing a relational syntax for schemas of important norm types along with their canonical lifecycles and providing a mapping from each schema to queries that compute instances of the schema in different lifecycle stages.  In essence, Custard supports a norm-based abstraction layer over underlying information stores such as databases and event logs. Specifically, it supports deadlines; complex events, including those based on aggregation; and norms that reference other norms.

We prove important correctness properties for Custard, including stability (once an event has occurred, it has occurred forever) and safety (a query returns a finite set of tuples).  Our compiler generates SQL queries from Custard specifications.  Writing out such SQL queries by hand is tedious and error-prone even for simple norms, thus demonstrating Custard's practical benefits.

The overarching vision of social machines is to facilitate social processes by having computers provide administrative support. We conceive of a social machine as a sociotechnical system (STS): a software-supported system in which autonomous principals such as humans and organizations interact to exchange information and services.  Existing approaches for social machines emphasize the technical aspects and inadequately support the meanings of social processes, leaving them informally realized in human interactions. We posit that a fundamental rethinking is needed to incorporate accountability, essential for addressing the openness of the Web and the autonomy of its principals.

We introduce Interaction-Oriented Software Engineering (IOSE) as a paradigm expressly suited to capturing the social basis of STSs. Motivated by promoting openness and autonomy, IOSE focuses not on implementation but on social protocols, specifying how social relationships, characterizing the accountability of the concerned parties, progress as they interact.  Motivated by providing computational support, IOSE adopts the accountability representation to capture the meaning of a social machine's states and transitions.

We demonstrate IOSE via examples drawn from healthcare.  We reinterpret the classical software engineering (SE) principles for the STS setting and show how IOSE is better suited than traditional software engineering for supporting social processes.  The contribution of this paper is a new paradigm for STSs, evaluated via conceptual analysis.

We propose Cupid, a language for specifying commitments that supports their information-centric aspects, and offers crucial benefits.  One, Cupid is first-order, enabling a systematic treatment of commitment instances.  Two, Cupid supports features needed for real-world scenarios such as deadlines, nested commitments, and complex event expressions for capturing the lifecycle of commitment instances.  Three, Cupid maps to relational database queries and thus provides a set-based semantics for retrieving commitment instances in states such as being violated,discharged, and so on.  We prove that Cupid queries are safe.  Four,to aid commitment modelers, we propose the notion of well-identified commitments, and finitely violable and finitely expirable commitments.  We give syntactic restrictions for obtaining such commitments.