2,511 research outputs found

    Fire design in safety engineering: likely fire curve for people’s safety

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    The present study analyses fire design settings according to Fire Safety Engineering (FSE) for the simulation of fire in civil activities and compares these simulations developed using natural and analytic fire curves. The simulated Heat Rate Release (HRR) curve, appropriately linearized, allows for the estimation of a Likely Fire Curve (LFC). The analytic curves have been introduced for the purpose of evaluating the strength and integrity of the structure, and the adoption of these curves in the fire safety engineering was made following the assumption that the phenomena of major intensity ensure the safe approach of fire design. This argument describes the method adopted for determining a likely fire model that guarantees a greater adherence of the virtualized phenomenon with respect to the potential event. The study showed that the analytic curve, adopted in order to verify the structural strength, in the beginning phases of fire produces fields of temperature and toxic concentrations lower than those obtained by simulation of the Likely Fire Curve. The assumption of the Likely Fire Curve model safeguards exposed people during self-rescue and emergency procedure. The programs used since 2011 for the simulation are FDS (Fire Dynamic Simulator v. 5.4.3) and Smokeview (5.4.8). Comparative analysis was developed using thermo-fluid dynamic parameters (temperature and heat release rate) relevant to the safety of the exposed persons; the case study focuses on children and employees of the nursery. The main result shows that the safety criterion, implicitly included in the analytical fire curves - normally used for fire resistance - doesn’t have the same applicability of a performance based approach on safety evaluation involving people. This paper shows that the Likely Fire Curve assumption involves a thermo-chemical stress more relevant to assessing the safety of exposed people

    Heat and Smoke Transport in a Residential-Scale Live Fire Training Facility: Experiments and Modeling

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    Understanding fire behavior is critical to effective tactical decision making on the fireground, particularly since fireground operations significantly impact the growth and spread of the fire. Computer-based simulation is a flexible, low-cost training methodology with proven success in fields such as pilot training, space, and military applications. Computer-based simulation may enhance fire behavior training and promote effective fireground decision making. This study evaluates the potential of the NIST Fire Dynamics Simulator (FDS) and Smokeview to be utilized as a part of a computer-based fire fighter trainer. Laboratory compartment fire experiments and full-scale fire experiments in a live-fire training facility were both conducted as part of the NIST Multiphase Study on Fire Fighter Safety and the Deployment of Resources. The laboratory experiments characterized the burning behavior of wood pallets to design a repeatable fire for use in the field experiments. The field experiments observed the effects of varying fire fighter deployment configurations on the performance times of fire fighter actions at a live fire training facility. These actions included opening the front door and fire suppression. Because the field experiments simulated numerous fire department responses to a repeatable fire, data were available to evaluate FDS simulation of heat and smoke spread, and changes in the thermal environment after the front door is opened and fire suppressed. In simulating the field experiments, the laboratory-measured heat release rate was used as an input. Given this assumption, this study has two objectives: 1) to determine if simulations accurately spread heat and smoke through a multi-level, multi-compartment live fire training facility 2) to determine if the simulations properly reproduce changes in the thermal environment that result from two typical fire fighter actions: opening the front door and fire suppression. In simulation, heat and smoke spread to measurement locations throughout the test structure at times closely matching experimentally measured times. Predictions of peak temperatures near the ceiling were within approximately 20% for all measurement locations. Hot gas layer temperature and depth were both predicted within 10% of the floor to ceiling height. After the front door was opened, temperature changes near the door at the highest and lowest measurement locations matched with temperature changes in the experiments. After fire suppression, FDS simulated temperature decay at a rate within the range measured in the field experiments and approximated the total rise of the hot gas layer interface in the burn compartment 250 seconds after suppression

    VELOS : a VR platform for ship-evacuation analysis

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    Virtual Environment for Life On Ships (VELOS) is a multi-user Virtual Reality (VR) system that aims to support designers to assess (early in the design process) passenger and crew activities on a ship for both normal and hectic conditions of operations and to improve ship design accordingly. This article focuses on presenting the novel features of VELOS related to both its VR and evacuation-specific functionalities. These features include: (i) capability of multiple users’ immersion and active participation in the evacuation process, (ii) real-time interactivity and capability for making on-the-fly alterations of environment events and crowd-behavior parameters, (iii) capability of agents and avatars to move continuously on decks, (iv) integrated framework for both the simplified and advanced method of analysis according to the IMO/MSC 1033 Circular, (v) enrichment of the ship geometrical model with a topological model suitable for evacuation analysis, (vi) efficient interfaces for the dynamic specification and handling of the required heterogeneous input data, and (vii) post-processing of the calculated agent trajectories for extracting useful information for the evacuation process. VELOS evacuation functionality is illustrated using three evacuation test cases for a ro–ro passenger ship

    Early Turn-taking Prediction with Spiking Neural Networks for Human Robot Collaboration

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    Turn-taking is essential to the structure of human teamwork. Humans are typically aware of team members' intention to keep or relinquish their turn before a turn switch, where the responsibility of working on a shared task is shifted. Future co-robots are also expected to provide such competence. To that end, this paper proposes the Cognitive Turn-taking Model (CTTM), which leverages cognitive models (i.e., Spiking Neural Network) to achieve early turn-taking prediction. The CTTM framework can process multimodal human communication cues (both implicit and explicit) and predict human turn-taking intentions in an early stage. The proposed framework is tested on a simulated surgical procedure, where a robotic scrub nurse predicts the surgeon's turn-taking intention. It was found that the proposed CTTM framework outperforms the state-of-the-art turn-taking prediction algorithms by a large margin. It also outperforms humans when presented with partial observations of communication cues (i.e., less than 40% of full actions). This early prediction capability enables robots to initiate turn-taking actions at an early stage, which facilitates collaboration and increases overall efficiency.Comment: Submitted to IEEE International Conference on Robotics and Automation (ICRA) 201

    Geographic interpretation: The role of spatial knowledge in the interpretation of natural resources

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    A surge of interest in geographic information has stemmed from the recent proliferation of Geographic Information Systems, Global Positioning Systems, and web-based tools such as Google Earth. This growing interest in geographic information has many implications for natural resource interpretation. Visitor centers and interpretive centers have long been sources of geographic information---providing maps and exhibits depicting a site or region. Such displays come in all shapes and sizes and in a variety of media, including maps, models, projections, animations and dioramas. Yet missing from the field of interpretation is research on the effectiveness of these tools in conveying geographic information to visitors.;A need for research on visitors\u27 understanding of geographic and spatial concepts has also surfaced in the social science literature on wildland fire. Researchers have repeatedly intimated a lack of knowledge by the public regarding the size of fires. Interpretation is used as a tool to increase knowledge about fire effects and to influence attitudes towards fire policy. Using interpretation to communicate spatial concepts pertaining to fire is therefore a logical extension. The recent shift to ecosystem management has created a need to communicate to the public about the nature of landscape-level processes. This raises the question of how people perceive large landscapes and how they learn about large-scale spaces.;In the study reported in this thesis, the spatial cognition of National Forest visitors was researched through the use of a survey. Visitors to the Columbia River Gorge National Scenic Area and Mt. Hood National Forest in Oregon were sampled from March-April, 2006. These visitors were asked about their cognitive representations of forest environments and their perceptions of the size of a recent fire. Three methods were adapted from research on human cognition: schema representations, cognitive mapping, and language structure. The results revealed a significant difference between male and female perceptions of fire size and a general lack of knowledge concerning fire size for both groups.;This thesis also reviews the literature on spatial cognition and provides a theoretical and empirical basis to suggest strategies for interpretation. Principles of geographic interpretation are outlined, and the terms geointerpretation and sense of space are suggested and defined

    ANALYZING THE POTENTIAL OF GRAPHICAL BUILDING INFORMATION FOR EMERGENCY RESPONSES: TOWARD A CONTROLLED EXPERIMENT

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    Improving the efficacy of emergency agencies like fire departments is receiving increased attention in academia and practice. In recent times, novel firefighter information technologies like digital plans and augmented reality systems have been proposed to better support the work of firefighters. These technologies, however, mostly result from technology-driven approaches and run a risk of failing the actual needs of the users. In this paper, we present the design of a controlled study to more rigorously examine firefighters’ needs for information. Considering the search and rescue task during a building fire as an exemplary case, we first identify informational potentials to support the work on site. Based on theories of situation awareness and cognitive science, we then hypothesize that graphical building information can facilitate the search and rescue task. To examine the hypotheses, we propose the design of a controlled, yet realistic laboratory experiment that was developed in cooperation with a Bavarian state firefighting academy. During the experiment, firefighter squads will be provided with different kinds of building information and evaluated with respect to their task performance. The results of the experiment are expected to provide implications for the design of novel firefighter information technologies and firefighters’ working routines
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