851,606 research outputs found
A Novel Method for Adaptive Control of Manufacturing Equipment in Cloud Environments
The ability to adaptively control manufacturing equipment, both in local and distributed environments, is becoming increasingly more important for many manufacturing companies. One important reason for this is that manufacturing companies are facing increasing levels of changes, variations and uncertainty, caused by both internal and external factors, which can negatively impact their performance. Frequently changing consumer requirements and market demands usually lead to variations in manufacturing quantities, product design and shorter product life-cycles. Variations in manufacturing capability and functionality, such as equipment breakdowns, missing/worn/broken tools and delays, also contribute to a high level of uncertainty. The result is unpredictable manufacturing system performance, with an increased number of unforeseen events occurring in these systems. Events which are difficult for traditional planning and control systems to satisfactorily manage. For manufacturing scenarios such as these, the use of real-time manufacturing information and intelligence is necessary to enable manufacturing activities to be performed according to actual manufacturing conditions and requirements, and not according to a pre-determined process plan. Therefore, there is a need for an event-driven control approach to facilitate adaptive decision-making and dynamic control capabilities. Another reason driving the move for adaptive control of manufacturing equipment is the trend of increasing globalization, which forces manufacturing industry to focus on more cost-effective manufacturing systems and collaboration within global supply chains and
manufacturing networks. Cloud Manufacturing is evolving as a new manufacturing paradigm to match this trend, enabling the mutually advantageous sharing of resources, knowledge and information between distributed companies and manufacturing units. One of the crucial objectives for Cloud Manufacturing is the coordinated planning, control and execution of discrete manufacturing operations in collaborative and networked environments. Therefore, there is also a need that such an event-driven control approach supports the control of distributed manufacturing equipment. The aim of this research study is to define and verify a novel and comprehensive method for adaptive control of manufacturing equipment in cloud environments. The presented research follows the Design Science Research methodology. From a review of research literature, problems regarding adaptive manufacturing equipment control have been identified. A control approach, building on a structure of event-driven Manufacturing Feature Function Blocks, supported by an Information Framework, has been formulated. The Function Block structure is constructed to generate real-time control instructions, triggered by events from the manufacturing environment. The Information Framework uses the concept of Ontologies and The Semantic Web to enable description and matching of manufacturing resource capabilities and manufacturing task requests in distributed environments, e.g. within Cloud Manufacturing. The suggested control approach has been designed and instantiated, implemented as prototype systems for both local and distributed manufacturing scenarios, in both real and virtual applications. In these systems, event-driven Assembly Feature Function Blocks for adaptive control of robotic assembly tasks have been used to demonstrate the applicability of the control approach. The utility and performance of these prototype systems have been tested, verified and evaluated for different assembly scenarios. The proposed control approach has many promising characteristics for use within both local and distributed environments, such as cloud environments. The biggest advantage compared to traditional control is that the required control is created at run-time according to actual manufacturing conditions. The biggest obstacle for being applicable to its full extent is manufacturing equipment controlled by proprietary control systems, with native control languages. To take the full advantage of the IEC Function Block control approach, controllers which can interface, interpret and execute these Function Blocks directly, are necessary
Decoding the neural substrates of reward-related decision making with functional MRI
Although previous studies have implicated a diverse set of brain regions in reward-related decision making, it is not yet known which of these regions contain information that directly reflects a decision. Here, we measured brain activity using functional MRI in a group of subjects while they performed a simple reward-based decision-making task: probabilistic reversal-learning. We recorded brain activity from nine distinct regions of interest previously implicated in decision making and separated out local spatially distributed signals in each region from global differences in signal. Using a multivariate analysis approach, we determined the extent to which global and local signals could be used to decode subjects' subsequent behavioral choice, based on their brain activity on the preceding trial. We found that subjects' decisions could be decoded to a high level of accuracy on the basis of both local and global signals even before they were required to make a choice, and even before they knew which physical action would be required. Furthermore, the combined signals from three specific brain areas (anterior cingulate cortex, medial prefrontal cortex, and ventral striatum) were found to provide all of the information sufficient to decode subjects' decisions out of all of the regions we studied. These findings implicate a specific network of regions in encoding information relevant to subsequent behavioral choice
A System for Distributed Mechanisms: Design, Implementation and Applications
We describe here a structured system for distributed mechanism design
appropriate for both Intranet and Internet applications. In our approach the
players dynamically form a network in which they know neither their neighbours
nor the size of the network and interact to jointly take decisions. The only
assumption concerning the underlying communication layer is that for each pair
of processes there is a path of neighbours connecting them. This allows us to
deal with arbitrary network topologies.
We also discuss the implementation of this system which consists of a
sequence of layers. The lower layers deal with the operations that implement
the basic primitives of distributed computing, namely low level communication
and distributed termination, while the upper layers use these primitives to
implement high level communication among players, including broadcasting and
multicasting, and distributed decision making.
This yields a highly flexible distributed system whose specific applications
are realized as instances of its top layer. This design is implemented in Java.
The system supports at various levels fault-tolerance and includes a
provision for distributed policing the purpose of which is to exclude
`dishonest' players. Also, it can be used for repeated creation of dynamically
formed networks of players interested in a joint decision making implemented by
means of a tax-based mechanism. We illustrate its flexibility by discussing a
number of implemented examples.Comment: 36 pages; revised and expanded versio
Distributed Hypothesis Testing with Social Learning and Symmetric Fusion
We study the utility of social learning in a distributed detection model with
agents sharing the same goal: a collective decision that optimizes an agreed
upon criterion. We show that social learning is helpful in some cases but is
provably futile (and thus essentially a distraction) in other cases.
Specifically, we consider Bayesian binary hypothesis testing performed by a
distributed detection and fusion system, where all decision-making agents have
binary votes that carry equal weight. Decision-making agents in the team
sequentially make local decisions based on their own private signals and all
precedent local decisions. It is shown that the optimal decision rule is not
affected by precedent local decisions when all agents observe conditionally
independent and identically distributed private signals. Perfect Bayesian
reasoning will cancel out all effects of social learning. When the agents
observe private signals with different signal-to-noise ratios, social learning
is again futile if the team decision is only approved by unanimity. Otherwise,
social learning can strictly improve the team performance. Furthermore, the
order in which agents make their decisions affects the team decision.Comment: 10 pages, 7 figure
Stewardship of the evolving scholarly record: from the invisible hand to conscious coordination
The scholarly record is increasingly digital and networked, while at the same time expanding in both the volume and diversity of the material it contains. The long-term future of the scholarly record cannot be effectively secured with traditional stewardship models developed for print materials. This report describes the key features of future stewardship models adapted to the characteristics of a digital, networked scholarly record, and discusses some practical implications of implementing these models.
Key highlights include:
As the scholarly record continues to evolve, conscious coordination will become an important organizing principle for stewardship models.
Past stewardship models were built on an "invisible hand" approach that relied on the uncoordinated, institution-scale efforts of individual academic libraries acting autonomously to maintain local collections.
Future stewardship of the evolving scholarly record requires conscious coordination of context, commitments, specialization, and reciprocity.
With conscious coordination, local stewardship efforts leverage scale by collecting more of less.
Keys to conscious coordination include right-scaling consolidation, cooperation, and community mix.
Reducing transaction costs and building trust facilitate conscious coordination.
Incentives to participate in cooperative stewardship activities should be linked to broader institutional priorities.
The long-term future of the scholarly record in its fullest expression cannot be effectively secured with stewardship strategies designed for print materials. The features of the evolving scholarly record suggest that traditional stewardship strategies, built on an “invisible hand” approach that relies on the uncoordinated, institution-scale efforts of individual academic libraries acting autonomously to maintain local collections, is no longer suitable for collecting, organizing, making available, and preserving the outputs of scholarly inquiry.
As the scholarly record continues to evolve, conscious coordination will become an important organizing principle for stewardship models. Conscious coordination calls for stewardship strategies that incorporate a broader awareness of the system-wide stewardship context; declarations of explicit commitments around portions of the local collection; formal divisions of labor within cooperative arrangements; and robust networks for reciprocal access. Stewardship strategies based on conscious coordination involve an acceleration of an already perceptible transition away from relatively autonomous local collections to ones built on networks of cooperation across many organizations, within and outside the traditional cultural heritage community
An Architecture for Integrated Intelligence in Urban Management using Cloud Computing
With the emergence of new methodologies and technologies it has now become
possible to manage large amounts of environmental sensing data and apply new
integrated computing models to acquire information intelligence. This paper
advocates the application of cloud capacity to support the information,
communication and decision making needs of a wide variety of stakeholders in
the complex business of the management of urban and regional development. The
complexity lies in the interactions and impacts embodied in the concept of the
urban-ecosystem at various governance levels. This highlights the need for more
effective integrated environmental management systems. This paper offers a
user-orientated approach based on requirements for an effective management of
the urban-ecosystem and the potential contributions that can be supported by
the cloud computing community. Furthermore, the commonality of the influence of
the drivers of change at the urban level offers the opportunity for the cloud
computing community to develop generic solutions that can serve the needs of
hundreds of cities from Europe and indeed globally.Comment: 6 pages, 3 figure
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