We propose Orpheus, a novel programming model for communicating agents based on information protocols and realized using cognitive programming. Whereas traditional models are focused on reactions to handle incoming messages, Orpheus supports organizing the internal logic of an agent based on its goals. We give an operational semantics for Orpheus and implement this semantics in an adapter to help build agents. We use the adapter to demonstrate how Orpheus simplifies the programming of decentralized multiagent systems compared to the reactive programming model.

An interaction protocol specifies how the member agents of a decentralized multiagent system may communicate to satisfy their respective stakeholders' requirements. We focus on information protocols, which are fully declarative specifications of interaction and support asynchronous communication. We offer Mambo, an approach for protocol design. Mambo identifies common patterns of requirements, provides a notation to express them, and a verification procedure. Mambo incorporates heuristics to generate small internal representations for efficiency. Experimental results demonstrate Mambo's effectiveness on practical protocols.

Protocols model multiagent systems (MAS) by capturing the communications between its agents. Belief-Desire-Intention (BDI) architectures provide an attractive way for organizing an agent in terms of cognitive concepts. Current BDI approaches, however, lack adequate support for engineering protocol-based agents. We describe Argus, an approach that melds recent advances in flexible, declarative communication protocols with BDI architectures. For concreteness, we adopt Jason as an exemplar of the BDI paradigm and show how to support protocol-based reasoning in it. Specifically, Argus contributes (1) a novel architecture and formal operational semantics combining protocols and BDI; (2) a code generation-based programming model that guides the implementation of agents; and (3) integrity checking for incoming and outgoing messages that help ensure that the agents are well-behaved. The Argus conceptual architecture builds quite naturally on top of Jason. Thus, Argus enables building more flexible multiagent systems while using a BDI architecture than is currently possible.

Abstract We conceptualize a decentralized software application as one constituted from autonomous agents that communicate via asynchronous messaging. Modern software paradigms such as microservices and settings such as the Internet of Things evidence a growing interest in decentralized applications. Constructing a decentralized application involves designing agents as independent local computations that coordinate successfully to realize the application’s requirements. Moreover, a decentralized application is susceptible to faults manifested as message loss, delay, and reordering. We contribute Mandrake , a programming model for decentralized applications that tackles these challenges without relying on infrastructure guarantees. Specifically, we adopt the construct of an information protocol that specifies messaging between agents purely in causal terms and can be correctly enacted by agents in a shared-nothing environment over nothing more than unreliable, unordered transport. Mandrake facilitates (1) implementing protocol-compliant agents by introducing a programming model; (2) transforming protocols into fault-tolerant ones with simple annotations; and (3) a declarative policy language that makes it easy to implement fault-tolerance in agents based on the capabilities in protocols. Mandrake’s significance lies in demonstrating a straightforward approach for constructing decentralized applications without relying on coordination mechanisms in the infrastructure, thus achieving some of the goals of the founders of networked computing from the 1970s.

A decentralized application involves multiple autonomous principals, e.g., humans and organizations. Autonomy motivates (i) specifying a decentralized application via a protocol that captures the interactions between the principals, and (ii) a programming model that enables each principal to independently (from other principals) construct its own protocol-compliant agent. An agent encodes its principal's decision making and represents it in the application. We contribute Deserv, the first protocol-based programming model for decentralized applications that is suited to the cloud. Specifically, Deserv demonstrates how to leverage function-as-a-service (FaaS), a popular serverless programming model, to implement agents. A notable feature of Deserv is the use declarative protocols to specify interactions. Declarative protocols support implementing stateful agents in a manner that naturally exploits the concurrency and autoscaling benefits offered by serverless computing.

Interaction-Oriented Programming (IOP) refers to multiagent concepts, languages, and programming models for engineering applications that are characterized by interactions between autonomous parties. Such applications arise in domains such as e-commerce, health care, and finance. Owing to the autonomy of the principals involved, such applications are conceptually decentralized. We demonstrate how to specify a decentralized application flexibly and how to engineer correct, fault-tolerant endpoints (agents) for the principals in a straightforward manner. Notably, the entire application is realized as agents communicating over an unordered, unreliable messaging infrastructure (our implementations in fact use UDP). IOP departs from traditional distributed systems approaches that rely on guarantees in the application's communication infrastructure, e.g., for ordering and fault tolerance. Notably, IOP shows how to address application semantics, the holy grail of distributed systems.

Engineering a decentralized multiagent system (MAS) requires realizing interactions modeled as a communication protocol between autonomous agents. We contribute Clouseau, an approach that takes a commitment-based specification of an interaction and generates a communication protocol amenable to decentralized enactment. We show that the generated protocol is (1) correct—realizes all and only the computations that satisfy the input specification; (2) safe—ensures the agents' local views remain consistent; and (3) live—ensures the agents can proceed to completion.

Communication protocols are central to engineering decentralized multiagent systems. Modern protocol languages are typically formal and address aspects of decentralization, such as asynchrony. However, modern languages differ in important ways in their basic abstractions and operational assumptions. This diversity makes a comparative evaluation of protocol languages a challenging task. We contribute a rich evaluation of diverse and modern protocol languages. Among the selected languages, Scribble is based on session types; Trace-C and Trace-F on trace expressions; HAPN on hierarchical state machines, and BSPL on information causality. Our contribution is four-fold. One, we contribute important criteria for evaluating protocol languages. Two, for each criterion, we compare the languages on the basis of whether they are able to specify elementary protocols that go to the heart of the criterion. Three, for each language, we map our findings to a canonical architecture style for multiagent systems, highlighting where the languages depart from the architecture. Four, we identify design principles for protocol languages as guidance for future research.

Advances in AI techniques and computing platforms have triggered a lively and expanding discourse on ethical decision making by autonomous agents. Much recent work in AI concentrates on the challenges of moral decision making from a decision-theoretic perspective, and especially the representation of various ethical dilemmas. Such approaches may be useful but in general are not productive because moral decision making is as context-driven as other forms of decision making, if not more. In contrast, we consider ethics not from the standpoint of an individual agent but of the wider sociotechnical systems (STS) in which the agent operates. Our contribution in this paper is the conception of ethical STS founded on governance that takes into account stakeholder values, normative constraints on agents, and outcomes (states of the STS) that obtain due to actions taken by agents. An important element of our conception is accountability, which is necessary for adequate consideration of outcomes that prima facie appear ethical or unethical. Focusing on STS provides a basis for tackling the difficult problems of ethics because the norms of an STS give an operational basis for agent decision making.

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.

Online discussions about software applications generate a large amount of requirements-related information. This information can potentially be usefully applied in requirements engineering; however currently, there are few systematic approaches for extracting such information. To address this gap, we propose Canary, an approach for extracting and querying requirements-related information in online discussions. The highlight of our approach is a high-level query language that combines aspects of both requirements and discussion in online forums. We give the semantics of the query language in terms of relational databases and SQL. We demonstrate the usefulness of the language using examples on real data extracted from online discussions. Our approach relies on human annotations of online discussions. We highlight the subtleties involved in interpreting the content in online discussions and the assumptions and choices we made to effectively address them. We demonstrate the feasibility of generating high-quality annotations by obtaining them from lay Amazon Mechanical Turk users.

Interactions among stakeholders and engineers is key to Requirements engineering (RE). Increasingly, such interactions take place online, producing large quantities of qualitative (natural language) and quantitative (e.g., votes) data. Although a rich source of requirements-related information, extracting such information from online forums can be nontrivial.We propose Canary, a tool-assisted approach, to facilitate systematic extraction of requirements-related information from online forums via high-level queries. Canary (1) adds structure to natural language content on online forums using an annotation schema combining requirements and argumentation ontologies, (2) stores the structured data in a relational database, and (3) compiles high-level queries in Canary syntax to SQL queries that can be run on the relational database.We demonstrate key steps in Canary workflow, including (1) extracting raw data from online forums, (2) applying annotations to the raw data, and (3) compiling and running interesting Canary queries that leverage the social aspect of the data.

No abstract available.

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 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.

We address the challenge of requirements engineering for sociotechnical systems, wherein humans and organizations supported by technical artifacts such as software interact with one another. Traditional requirements models emphasize the goals of the stakeholders above their interactions. However, the participants in a sociotechnical system may not adopt the goals of the stakeholders involved in its specification. We motivate, Protos, a requirements engineering approach that gives prominence to the interactions of autonomous parties and specifies a sociotechnical system in terms of its participants' social relationships, specifically, commitments. The participants can adopt any goal they like, a key basis for innovative behavior, as long as they interact according to the commitments. Protos describes an abstract requirements engineering process as a series of refinements that seek to satisfy stakeholder requirements by incrementally expanding a specification set and an assumption set, and reducing requirements until all requirements are accommodated. We demonstrate this process via the London Ambulance System described in the literature.

No abstract available.

Increasingly, software engineering involvesopensystems consisting of autonomous and heterogeneous participants oragentswho carry out loosely coupled interactions. Accordingly, understanding and specifying communications among agents is a key concern. A focus on ways to formalizemeaningdistinguishes agent communication from traditional distributed computing: meaning provides a basis for flexible interactions and compliance checking. Over the years, a number of approaches have emerged with some essential and some irrelevant distinctions drawn among them. As agent abstractions gain increasing traction in the software engineering of open systems, it is important to resolve the irrelevant and highlight the essential distinctions, so that future research can be focused in the most productive directions. This article is an outcome of extensive discussions among agent communication researchers, aimed at taking stock of the field and at developing, criticizing, and refining their positions on specific approaches and future challenges. This article serves some important purposes, including identifying (1) points of broad consensus; (2) points where substantive differences remain; and (3) interesting directions of future work.

No abstract available.

Business service engagements involve processes that extend across two or more autonomous organizations. Because of regulatory and competitive reasons, requirements for cross-organizational business processes often evolve in subtle ways. The changes may concern the business transactions supported by a process, the organizational structure of the parties participating in the process, or the contextual policies that apply to the process. Current business process modeling approaches handle such changes in an ad hoc manner, and lack a principled means for determining what needs to be changed and where. Cross-organizational settings exacerbate the shortcomings of traditional approaches because changes in one organization can potentially affect the workings of another. This article describes Amoeba, a methodology for business processes that is based on business protocols . Protocols capture the business meaning of interactions among autonomous parties via commitments. Amoeba includes guidelines for (1) specifying cross-organizational processes using business protocols, and (2) handling the evolution of requirements via a novel application of protocol composition. This article evaluates Amoeba using enhancements of a real-life business scenario of auto-insurance claim processing, and an aerospace case study.

Business process modeling and enactment are notoriously complex, especially in open settings, where business partners are autonomous, requirements must be continually finessed, and exceptions frequently arise because of real-world or organizational problems. Traditional approaches, which attempt to capture processes as monolithic flows, have proven inadequate in addressing these challenges. We propose (business) protocols as components for developing business processes. A protocol is an abstract, modular, publishable specification of an interaction among different roles to be played by different participants. When instantiated with the participants' internal policies, protocols yield concrete business processes. Protocols are reusable and refinable, thus simplifying business process design. We show how protocols and their composition are theoretically founded in the phi;-calculus.