15,600 research outputs found
Towards formal models and languages for verifiable Multi-Robot Systems
Incorrect operations of a Multi-Robot System (MRS) may not only lead to
unsatisfactory results, but can also cause economic losses and threats to
safety. These threats may not always be apparent, since they may arise as
unforeseen consequences of the interactions between elements of the system.
This call for tools and techniques that can help in providing guarantees about
MRSs behaviour. We think that, whenever possible, these guarantees should be
backed up by formal proofs to complement traditional approaches based on
testing and simulation.
We believe that tailored linguistic support to specify MRSs is a major step
towards this goal. In particular, reducing the gap between typical features of
an MRS and the level of abstraction of the linguistic primitives would simplify
both the specification of these systems and the verification of their
properties. In this work, we review different agent-oriented languages and
their features; we then consider a selection of case studies of interest and
implement them useing the surveyed languages. We also evaluate and compare
effectiveness of the proposed solution, considering, in particular, easiness of
expressing non-trivial behaviour.Comment: Changed formattin
Quire: Lightweight Provenance for Smart Phone Operating Systems
Smartphone apps often run with full privileges to access the network and
sensitive local resources, making it difficult for remote systems to have any
trust in the provenance of network connections they receive. Even within the
phone, different apps with different privileges can communicate with one
another, allowing one app to trick another into improperly exercising its
privileges (a Confused Deputy attack). In Quire, we engineered two new security
mechanisms into Android to address these issues. First, we track the call chain
of IPCs, allowing an app the choice of operating with the diminished privileges
of its callers or to act explicitly on its own behalf. Second, a lightweight
signature scheme allows any app to create a signed statement that can be
verified anywhere inside the phone. Both of these mechanisms are reflected in
network RPCs, allowing remote systems visibility into the state of the phone
when an RPC is made. We demonstrate the usefulness of Quire with two example
applications. We built an advertising service, running distinctly from the app
which wants to display ads, which can validate clicks passed to it from its
host. We also built a payment service, allowing an app to issue a request which
the payment service validates with the user. An app cannot not forge a payment
request by directly connecting to the remote server, nor can the local payment
service tamper with the request
The Productivity of Schools and Other Local Public Goods Providers
I construct an agency model of local public goods producers with special reference to public schools. The model assumes that households make Tiebout choices among jurisdictions, but it has more realistic assumptions about information and the cost of residential mobility. I examine producers' effort and rent under local property tax finance and centralized finance. I show that, if there are a sufficient number of jurisdictions to choose among, conventional local property tax finance substantially reduces the agency problem and associated loss of productivity. Specifically, I demonstrate that local property tax finance can attain about as much productivity as a social planner with centralized finance can, even if the social planner is armed with more information that a real social planner could plausibly have. The key insight is that decentralized Tiebout choices make some information the social planner would need verifiable and other information unnecessary.
Towards a Framework for Developing Mobile Agents for Managing Distributed Information Resources
Distributed information management tools allow users to author, disseminate, discover and manage information within large-scale networked environments, such as the Internet. Agent technology provides the flexibility and scalability necessary to develop such distributed information management applications. We present a layered organisation that is shared by the specific applications that we build. Within this organisation we describe an architecture where mobile agents can move across distributed environments, integrate with local resources and other mobile agents, and communicate their results back to the user
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