9479405
Topological network design of state-dependent queueing networks
29643487
Stochastic network evacuation models
Abstract Stochastic network evacuation models are crucial for the safe evacuation of occupants from buildings. In this paper, we compare an analytical closed queueing network and a simulation model for analyzing the evacuation of occupants from a hospital. Evacuation times, arc congestion, and optimization of the evacuation routes and staff assigned to the evacuation network are included.
10906069
Optimal multimodal fusion for multimedia data analysis
Considerable research has been devoted to utilizing multimodal features for better understanding multimedia data. However, two core research issues have not yet been adequately addressed. First, given a set of features extracted from multiple media sources (e.g., extracted from the visual, audio, and caption track of videos), how do we determine the best modalities? Second, once a set of modalities has been identified, how do we best fuse them to map to semantics? In this paper, we propose a two-step approach. The first step finds <i>statistically independent modalities</i> from raw features. In the second step, we use <i>super-kernel fusion</i> to determine the optimal combination of individual modalities. We carefully analyze the tradeoffs between three design factors that affect fusion performance: <i>modality independence</i>, <i>curse of dimensionality</i>, and <i>fusion-model complexity</i>. Through analytical and empirical studies, we demonstrate that our two-step approach, which achieves a careful balance of the three design factors, can improve class-prediction accuracy over traditional techniques.
45728102
Causal Identification in Design Networks
When planning and designing a policy intervention and evaluation, the policy maker will have to define a strategy which will define the (conditional independence) structure of the available data. Here, Dawid’s extended influence diagrams are augmented by including ‘experimental design’ decisions nodes within the set of intervention strategies to provide semantics to discuss how a ‘design’ decision strategy (such as randomisation) might assist the systematic identification of intervention causal effects. By introducing design decision nodes into the framework, the experimental design underlying the data available is made explicit. We show how influence diagrams might be used to discuss the efficacy of different designs and conditions under which one can identify ‘causal’ effects of a future policy intervention. The approach of this paper lies primarily within probabilistic decision theory.
9864663
Toward alternative metrics of journal impact: A comparison of download and citation data
We generated networks of journal relationships from citation and download data, and determined journal impact rankings from these networks using a set of social network centrality metrics. The resulting journal impact rankings were compared to the ISI IF. Results indicate that, although social network metrics and ISI IF rankings deviate moderately for citation-based journal networks, they differ considerably for journal networks derived from download data. We believe the results represent a unique aspect of general journal impact that is not captured by the ISI IF. These results furthermore raise questions regarding the validity of the ISI IF as the sole assessment of journal impact, and suggest the possibility of devising impact metrics based on usage information in general.
6106969
Service-Based Distributed Querying on the Grid
Service-based approaches (such as Web Services and the Open Grid Services Architecture) have gained considerable attention recently for supporting distributed application development in e-business and e-science. The emergence of a service-oriented view of hardware and software resources raises the question as to how database management systems and technologies can best be deployed or adapted for use in such an environment. This paper explores one aspect of service-based computing and data management, viz., how to integrate query processing technology with a service-based Grid. The paper describes in detail the design and implementation of a service-based distributed query processor for the Grid. The query processor is service-based in two orthogonal senses: firstly, it supports querying over data storage and analysis resources that are made available as services, and, secondly, its internal architecture factors out as services the functionalities related to the construction of distributed query plans on the one hand, and to their execution over the Grid on the other. The resulting system both provides a declarative approach to service orchestration in the Grid, and demonstrates how query processing can benefit from dynamic access to computational resources on the Grid.
7641862
Multi-granular detection of regional semantic concepts
A large number of interesting visual semantic concepts occur at a sub-frame granularity in images and occupy one or more regions at the sub-frame level. Detecting these concepts is a challenge due to segmentation imperfections. We propose multi-granular detection of visual concepts that have regional support. We build a single set of support vector machine based binary concept models from the training set with manually marked up regions. In this paper we show that detection can he significantly improved by scoring these models over multiple granularities in the test set images, where the regions are automatically detected a.$ a preprocessing step in detection. Using 27 regional semantic concepts from the NIST TRECVID 2003 common annotation lexicon and the corpus we demonstrate that multigranular detection leads to improvement in detection.