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31.
32.
Several researchers have recently investigated the connection between reinforcement learning and classification. We are motivated
by proposals of approximate policy iteration schemes without value functions, which focus on policy representation using classifiers
and address policy learning as a supervised learning problem. This paper proposes variants of an improved policy iteration
scheme which addresses the core sampling problem in evaluating a policy through simulation as a multi-armed bandit machine.
The resulting algorithm offers comparable performance to the previous algorithm achieved, however, with significantly less
computational effort. An order of magnitude improvement is demonstrated experimentally in two standard reinforcement learning
domains: inverted pendulum and mountain-car. 相似文献
33.
A steady-state interval operability methodology is introduced here for multivariable non-square systems with fewer inputs than output variables to be used in the design of model-based constrained controllers (MPC, DMC). For such systems, set-point control is not possible for all the outputs and interval control is needed. The proposed iterative approach enables the selection of the needed interval constraints systematically, so that the tightest possible control is achieved without rendering the control problem infeasible. The application of this methodology to high-dimensional industrial problems characterizing processes of Air Products and Chemicals and DuPont shows that very significant reduction of the constrained region can be achieved from the steady-state point of view. Ratios of the initial to the calculated volume of the constrained regions examined range between 104 and 108. 相似文献
34.
Lambrini Seremeti Christos Goumopoulos Achilles Kameas 《Pervasive and Mobile Computing》2009,5(5):574-591
As the computer disappears in the environments surrounding our activities, the objects therein become augmented with sensors, actuators, processors, memories, wireless communication modules and they can receive, store, process and transmit information. In addition to objects, spaces also undergo a change towards becoming smart and eventually Ambient Intelligence (AmI) spaces. In order to model the way everyday activities are carried out within an AmI environment, we introduce the notion of “activity sphere”. In this paper, we are interested in the ontology-based representation of activity spheres from two different perspectives (as creators and as observers), as well as the modeling and control of the dynamic nature of activity spheres. 相似文献
35.
We study aG/G/1 queueing system with a bursty arrival process. Based on a general model for such a bursty process, we derive infinitesimal perturbation analysis (IPA) derivative estimators of the mean system time with respect to various parameters of interest. The cases of both complete and partial state information are considered. To ensure unbiasedness and strong consistency of the estimators, different sample path representations are developed such that sample functions are continuous with respect to the particular parameter of interest. Some of these representations are applicable to a wider class of gradient estimation problems where sample path discontinuities arise. Simulation results are included to compare the convergence rates and variance properties of the different IPA estimators developed. 相似文献
36.
The AT&T Internet Difference Engine (AIDE) is a system that finds and displays changes to pages on the World Wide Web. The system consists of several components, including a webcrawler that detects changes, an archive of past versions of pages, a tool called HtmlDiff to highlight changes between versions of a page, and a graphical interface to view the relationship between pages over time. This paper describes AIDE, with an emphasis on the evolution of the system and experiences with it. It also raises some sociological and legal issues. 相似文献
37.
Soft computing continuously gains interest in many fields of academic and industrial domain; among the most notable characteristics for using soft computing methodological tools is the ability to handle with vague and imprecise data in decision making processes. Similar conditions are often encountered in requirements engineering. In this paper, we introduce the PriS approach, a security and privacy requirements engineering framework which aims at incorporating privacy requirements early in the system development process. Specifically, PriS provides a set of concepts for modelling privacy requirements in the organisation domain and a systematic way-of-working for translating these requirements into system models. The conceptual model of PriS uses a goal hierarchy structure. Every privacy requirement is either applied or not on every goal. To this end every privacy requirement is a variable that can take two values [0,1] on every goal meaning that the requirements constraints the goal (value 1) or not (value 0). Following this way of working PriS ends up suggesting a number of implementation techniques based on the privacy requirements constraining the respective goals. Taking into account that the mapping of privacy variables to a crisp set consisting of two values [0,1] is constraining, we extend also the PriS framework so as to be able to address the degree of participation of every privacy requirement towards achieving the generic goal of privacy. Therefore, we propose a fuzzification of privacy variables that maps the expression of the degree of participation of each privacy variable to the [0,1] interval. We also present a mathematical framework that allows the concurrent management of combined independent preferences towards the necessity of a privacy measure; among the advantages of the presented extended framework is the scalability of the approach in such a way that the results are not limited by the number of independent opinions or by the number of factors considered while reasoning for a specific selection of privacy measures. 相似文献
38.
Operator context scanning to support high segmentation rates for real time license plate recognition
Ioannis Giannoukos Author Vitae Christos-Nikolaos Anagnostopoulos Author VitaeAuthor Vitae Eleftherios Kayafas Author Vitae 《Pattern recognition》2010,43(11):3866-3878
Introducing high definition videos and images in object recognition has provided new possibilities in the field of intelligent image processing and pattern recognition. However, due to the large amount of information that needs to be processed, the computational costs are high, making the HD systems slow. To this end, a novel algorithm applied to sliding window analysis, namely Operator Context Scanning (OCS), is proposed and tested on the license plate detection module of a License Plate Recognition (LPR) system. In the LPR system, the OCS algorithm is applied on the Sliding Concentric Windows pixel operator and has been found to improve the LPR system’s performance in terms of speed by rapidly scanning input images focusing only on regions of interest, while at the same time it does not reduce the system effectiveness. Additionally, a novel characteristic is presented, namely, the context of the image based on a sliding windows operator. This characteristic helps to quickly categorize the environmental conditions upon which the input image was taken. The algorithm is tested on a data set that includes images of various resolutions, acquired under a variety of environmental conditions. 相似文献
39.
Christos Bouras Apostolos Gkamas Georgios Kioumourtzis 《Journal of Network and Systems Management》2011,19(2):143-177
In this paper, we present Adaptive Smooth Simulcast Protocol (ASSP) for simulcast transmission of multimedia data over best-effort
networks. ASSP is a new multiple-rate protocol that implements a single rate TCP-friendly protocol as the underlying congestion
control mechanism for each simulcast stream. The key attributes of ASSP are: (a) TCP-friendly behavior, (b) adaptive per-stream
transmission rates, (c) adaptive scalability to large sets of receivers and (d) smooth transmission rates that are suitable
for multimedia applications. We evaluate the performance of ASSP under an integrated simulation environment which combines
the measurements of both network and video performance metrics. We also compare ASSP against other proposed solutions and
the results demonstrate that the performance of ASSP is significantly better than the tested solutions. Finally, ASSP is a
practical solution with very low implementation complexity for video transmission over best-effort networks. 相似文献
40.
A repairable queueing model with a two-phase service in succession, provided by a single server, is investigated. Customers arrive in a single ordinary queue and after the completion of the first phase service, either proceed to the second phase or join a retrial box from where they retry, after a random amount of time and independently of the other customers in orbit, to find a position for service in the second phase. Moreover, the server is subject to breakdowns and repairs in both phases, while a start-up time is needed in order to start serving a retrial customer. When the server, upon a service or a repair completion finds no customers waiting to be served, he departs for a single vacation of an arbitrarily distributed length. The arrival process is assumed to be Poisson and all service and repair times are arbitrarily distributed. For such a system the stability conditions and steady state analysis are investigated. Numerical results are finally obtained and used to investigate system performance. 相似文献