People Indoors Research Articles

Distributed Emergency Guiding with Evacuation Time Optimization Based on Wireless Sensor Networks

This paper proposes a load-balancing framework for distributed emergency guiding based on wireless sensor networks. A load-balancing guiding scheme is designed and an analytical model is derived to reduce the total evacuation time of people indoors. The guiding scheme can provide the fastest path for people to reach an exit according to the evacuation time estimated using the analytical model. Based on thorough research, this is the first distributed solution in which corridor capacity and length, exit capacity, and the concurrent movement and distribution of people are considered in estimating the evacuation time and planning escape paths. Using the proposed framework, congestion in corridors and at exits can be eased to substantially reduce the total evacuation time. Analytical and simulation results show that this approach outperforms existing schemes and can prevent people from following local-optimal guiding directions that increase the evacuation time. A prototype called the Load-balancing Emergency Guiding System (LEGS) is implemented; this system can be used to compare the evacuation times and guiding directions provided by existing schemes and the proposed scheme for various distributions of people.

Effects of Positioning Data Quality and Navigation Models on Map-Matching of Indoor Positioning Data

AbstractWith rising complexity of indoor environments and growing demand for positioning and tracking of people (such as occupants and field workers) indoors, there has been an increasing need to have accurate and reliable indoor positioning. In this paper, the effects of (1) the quality of positioning data and (2) the types of navigation models on the accuracy of map-matching of indoor positioning data are evaluated. Sensitivity analyses on the quality of two different types of positioning data, namely, (1) absolute point-positioning data and (2) relative point-positioning data have been carried out. Two different types of navigation models, namely, (1) network models and (2) metric models, have been evaluated to examine their effect on the accuracy of the map-matching results. Eight different map-matching algorithms were selected and their accuracies were assessed in six different indoor data-collection routes containing spaces with varying density, sizes, and shapes. The results show different ways thr...

Signage Versus Environmental Affordances: Is the Explicit Information Strong Enough to Guide Human Behavior During a Wayfinding Task?

AbstractThis study aims to explore how people behave when they have to find a location within a complex building and are confronted with situations where directional signage (i.e., explicit information) is in opposition to environmental affordances that naturally direct users towards a specific path, creating a situation with conflicting information (e.g., a brighter corridor vs. a darker corridor but with a directional sign indicating to follow the darker one). A virtual reality–based methodology was used and a between‐subject design was considered. Thus, participants were given the tasks of finding three publicly accessible central points in a virtual hotel and confronted with a two forced‐choice task of local scenes in which environmental variables (i.e., corridor width and brightness) and signage varied systematically, in two experimental conditions (i.e., neutral and signage). For the signage condition, signs were inserted to explicitly point in the opposite direction than that implicitly suggested by the environmental affordances, creating situations with conflicting information. Results indicate that environmental variables were able to direct people indoors acting as environmental affordances. Users preferred to follow the wider and brighter paths. However, when directional signage pointed in the opposite direction of the paths preferred by the participants, most of them complied with signage.

Mobile Node Localization Focusing on Stop-and-Go Behavior of Indoor Pedestrians

Despite recent advances in localization technology for mobile devices, to provide real-time position information to people indoors is still a big challenge; usually there is a trade-off between localization accuracy and infrastructural costs (e.g., dense anchor deployment). A possible solution would be employing cooperative approaches which utilize estimated positions of surrounding mobile nodes to complement a small number of anchors. However, it often results in poor estimation accuracy since a temporary large position error due to node mobility easily propagates to neighbor nodes. This paper presents a novel cooperative localization algorithm that addresses this problem by focusing on “stop-and-go behavior” of indoor pedestrians. The key idea is to collaboratively find movement state (moving or static) of each node based on peer-to-peer distance measurement which is inherently necessary for cooperative localization, and use only static nodes as reference points for localization to avoid potential accuracy deterioration. Also, nodes in static state can reduce localization frequency to conserve battery power, keeping the tracking quality. Through extensive simulations, we have demonstrated the performance of our method in terms of accuracy and energy efficiency. The effectiveness in a real application scenario has been also confirmed using a measurement-based sensor model and real mobility traces.

Behavior of Montandoniola confusa Streito & Matocq (Hemiptera: Anthocoridae) preying upon gall-forming thrips Gynaikothrips ficorum Marchal (Thysanoptera: Phlaeothripidae)

The gall-forming thrips Gynaikothrips ficorum Marchal (Thysanoptera: Phlaeothripidae) is recorded in all regions where its host plant, Ficus microcarpa (Marchal) (Moraceae), has been cultivated as an urban and interior landscape plant species, including potted plants and bonsai. Similarly, the thrips predator Montandoniola confusa Streito & Matocq (Hemiptera: Anthocoridae) has generally followed the prey distribution. The gall induced by thrips degrades the plant foliage, and the thrips themselves can be annoying for people both outdoors and indoors. The galls, however, create a microcosm with all developmental stages of the thrips and its predator. In this study we present the first records of M. confusa in South America, document the species’ widespread concomitant occurrence across Brazil, and report our studies of three aspects of M. confusa predation upon the eggs, larvae/prepupae, and adults of G. ficorum thrips: (i) functional response of the predator adult female as a function of different densities of thrips eggs, larvae/prepupae and adults separately: (ii) predation on eggs by adult M. confusa with adult thrips present in the gall; and (iii) adult M. confusa prey preferences when all thrips stages occurred simultaneously in the gall. For all three thrips life stages tested, the predator exhibited a type II functional response. Despite the availability of different life stages in the gall, M. confusa adults are capable of preying upon all life stages of G. ficorum, predation was preferentially on thrips eggs, with an estimated ∼10-fold greater predation on eggs compared to larvae/prepupae and adult thrips. Egg predation was unaffected by the presence of defensive adult thrips in the gall under low densities (<30 eggs/gall) but when egg densities were greater than 30 eggs/gall, it was reduced when adult thrips were present. However, the relative number of thrips adults per gall did not statistically change the outcome.

A Prototype Navigation System for Guiding Blind People Indoors using NXT Mindstorms

People with visual impairment face enormous difficulties in terms of their mobility as they do not have enough information about their location and orientation with respect to traffic and obstacles on their route. Visually impaired people can navigate unknown areas by relying on the assistance of canes, other people, or specially trained guide dogs. The traditional ways of using guide dogs and long-cane only help to avoid obstacles, not to know where they are. The research presented in this paper introduces a mobile assistant navigation prototype to locate and direct blind people indoors. Since most of the existing navigation systems developed so far for blind people employ a complex conjunction of positioning systems, video cameras, location-based and image processing algorithms, we designed an affordable low-cost prototype navigation system for orienting and tracking the position of blind people in complex environments. The prototype system is based on the inertial navigation system and experiments have been performed on NXT Mindstorms platform.

Support Vector Machine and Probability Neural Networks in a Device-Free Passive Localization (DFPL) Scenario

Abstract The holy grail of tracking people indoors is being able to locate them when they are not carrying any wireless tracking devices. The aim is to be able to track people just through their physical body interfering with a standard wireless network that would be in most peoples home. The human body contains about 70% water which attenuates the wireless signal reacting as an absorber. The changes in the signal along with prior fingerprinting of a physical location allow identification of a person’s location. This paper is focused on taking the principle of Device-free Passive Localisation (DfPL) and applying it to be able to actually distinguish if there is more than one person in the environment. In order to solve this problem, we tested a Support Vector Machine (SVM) classifier with kernel functions such as Linear, Quadratic, Polynomial, Gaussian Radial Basis Function (RBF) and Multilayer Perceptron (MLP), and a Probabilistic Neural Network (PNN) in order to detect movement based on changes in the wireless signal strength.

Real-time computational processing and implementation for concealed object detection

Millimeter wave (MMW) readily penetrates fabrics, thus it can be used to detect objects concealed under clothing. A passive MMW imaging system can operate as a stand-off type sensor that scans people both indoors and outdoors. However, because of the diffraction limit and low signal level, the imaging system often suffers from low image quality. Therefore, suitable computational processing would be required for automatic analysis of the images. The authors present statistical and computational algorithms and their implementations for real-time concealed object detection. The histogram of the image is modeled as a Gaussian mixture distribution, and hidden object areas are segmented by a multilevel scheme involving the expectation-maximization algorithm. The complete algorithm has been implemented in both MATLAB and C++. Experimental and simulation results confirm that the implemented system can achieve real-time detection of concealed objects.

Book Review: Blogistan: The Internet and Politics in Iran

Blogistan: The Internet and Politics in Iran. Annabelle Sreberny and Gholam Khiabany. London: I.B. Tauris, 2010. 240 pp. $75 hbk. $27.50 pbk.In June the world was riveted by news of demonstrators taking to the streets in Tehran to protest the reelection of Mahmud Ahmadinejad. Images of a young woman, Neda Agha-Sultan, dying in the street were posted on YouTube and watched by hundreds of thousands. Ultimately, Iran's Twitter Revolution did not lead to a regime change. Although Blogistan: The Internet and Politics in Iran was largely written before the uprising, Annabelle Sreberny and Gholam Khiabany explain the roots of the protest and give context to the events of 2009.Sreberny, professor of global media and communications at the University of London and president of the International Association of Media and Communication Research, builds on her earlier studies of communication during the Iranian revolution in 1979. Khiabany, a reader in international communication at London Metropolitan University, has written about the paradox of modernity in the Iranian media.In Blogistan, they draw on news accounts, as well as reports from Iranian bloggers and previously published studies, to describe the growth of the Internet and blogosphere in Iran. They argue that when the country's regime suppressed traditional media and face-to-face political discourse, the Internet became the space for political debate. In creating an atmosphere of suspicion and keeping people indoors with little to do but fiddle with computers, the regime helped to induce a generation of digital adepts, the consequences of which it was to rue in the summer of 2009, they write.Sreberny and Khiabany carefully make their case, reaching back in history when necessary to give context to present developments. In chapter 1, the authors describe how the Iranian government both used and sought to curtail access to the Internet following the 1979 revolution. The government's ambivalence toward technology gave rise to ad hoc and contradictory regulations. Internet growth in Iran has been phenomenal. In 2006, eleven million Iranians had access to the Internet, an increase of 50% over the previous year. Still, Internet usage has been stymied, not only by government restrictions, but by the country's financial crisis, which leaves citizens with less money to spend on computers and Internet access fees.In chapter 2, the authors explore reasons behind the growth of the Iranian blogosphere and conclude that despite political oppression-and even because of it-Iranians have embraced blogging as a means of self-expression. Sreberny and Khiabany estimate that there are seventy thousand Iranian blogs; many are personal diaries that espouse the writers' interests in sports, games, and entertainment. …

An evaluation of indoor location determination technologies

The development of real-time locating systems (RTLS) has become an important add-on to many existing location aware systems. While GPS has solved most of the outdoor RTLS problems, it fails to repeat this success indoors. A number of technologies have been used to address the indoor tracking problem. The ability to accurately track the location of people indoors has many applications ranging from medical, military and logistical to entertainment. However, current systems cannot provide continuous real-time tracking of a moving target or lose capability when coverage is poor. The deployment of a real-time location determination system however is fraught with problems. To date there has been little research into comparing commercial systems on the market with regard to informing IT departments as to their performance in various aspects which are important to tracking devices and people in relatively confined areas. This article attempts to provide such a useful comparison by providing a review of the practicalities of installing certain location-sensing systems. We also comment on the accuracies achieved and problems encountered using the position-sensing systems.

Consequence analysis to buildings from bursting cylindrical vessels

AbstractDamage effects to buildings must be taken into account when performing consequence analysis, because people indoors can be affected by such damage. The objective of this article is to provide a methodology for estimating damage to buildings from the pressure wave produced by bursting cylindrical vessels, by combining characteristic overpressure‐impulse‐distance curves with PROBIT equations. This methodology allows the damage to be shown in the same diagram as the overpressure, impulse, and distance. Diagrams and equations are presented to determine minor damage to brick buildings of four or less floors (broken windows, displacement of doors and window frames, tile displacement, etc), major structural damage (cracks in walls, collapse of some walls), and collapse (the damage is so extensive that the building is partially or totally demolished). © 2009 American Institute of Chemical Engineers Process Saf Prog, 2009

International Circumpolar Surveillance, an Arctic network for the surveillance of infectious diseases.

Peoples of the Arctic and sub-Arctic regions live in social and physical environments that differ substantially from those of their more southern-dwelling counterparts. The cold northern climate keeps people indoors, amplifying the effects of household crowding, smoking, and inadequate ventilation on person-to-person spread of infectious disease. The emergence of antimicrobial drug resistance among bacterial pathogens, the reemergence of tuberculosis, the entrance of HIV into Arctic communities, and the spectre of pandemic influenza or the sudden emergence and introduction of new viral pathogens such as severe acute respiratory syndrome are of increasing concern to residents, governments, and public health authorities. The International Circumpolar Surveillance system is a network of hospital, public health agencies, and reference laboratories throughout the Arctic linked together to collect, compare, and share uniform laboratory and epidemiologic data on infectious diseases and assist in the formulation of prevention and control strategies.

An algorithm for fast, model-free tracking indoors

Tracking people and objects indoors from signal strength measurements has applications as diverse as security monitoring, self-guided museum tours, and personalization of communications services. Accurate dynamic tracking in real-time has been elusive, though, because signal propagation in buildings and the paths that people follow are complex. This paper proposes a simple algorithm for indoor tracking that requires neither a propagation model nor a motion model. It is also simple to compute, requiring only standard tools: Delaunay triangulation, linear interpolation, moving averaging, and local regression. Experiments with real data and simulations based on real data show that the algorithm is not only simple, it is effective.

A 3D Feature-Based Binocular Tracking Algorithm

This paper presents a 3D feature-based binocular tracking algorithm for tracking crowded people indoors. The algorithm consists of a two stage 3D feature points grouping method and a robust 3D feature-based tracking method. The two stage 3D feature points grouping method can use kernel-based ISODATA method to detect people accurately even though the part or almost full occlusion occurs among people in surveillance area. The robust 3D feature-based Tracking method combines interacting multiple model (IMM) method with a cascade multiple feature data association method. The robust 3D feature-based tracking method not only manages the generation and disappearance of a trajectory, but also can deal with the interaction of people and track people maneuvering. Experimental results demonstrate the robustness and efficiency of the proposed framework. It is real-time and not sensitive to the variable frame to frame interval time. It also can deal with the occlusion of people and do well in those cases that people rotate and wriggle.

Building calibration for IAQ management

Demand Control System (DCV) is designed to optimise the energy consumption with respect to the demand of outdoor air quantity based on the number of people indoors. However, if significant indoor pollutant sources exist, which is not a function of the number of people, the DCV may cause the indoor air quality to be unacceptable. This paper discusses a procedure of calibrating the building in respect of managing the indoor air quality. The objective is to set the minimum fresh air quantity which is a function of the indoor pollutant concentrations rather than metabolic carbon dioxide. Radon is used as an example because it is a common pollutant embedded in the building materials of high-rise buildings in Hong Kong. This paper also presents a year-round record of the indoor air quality in a typical high-rise building which is very useful for building indoor air quality (IAQ) design.

Potential for Anopheles campestris (Diptera: Culicidae) to transmit malaria parasites in Pa Rai subdistrict (Aranyaprathet, Sa Kaeo Province), Thailand.

Member(s) of the Anopheles barbirostris group Reid, particularly Anopheles barbirostris and Anopheles campestris Reid are the suspected vectors of Plasmodium vivax in Pa Rai (Aranyaprathet, Sa Kaeo province). To determine if An. barbirostris, An. campestris, or both, are present in Pa Rai and to determine their potential to transmit malaria, a field and laboratory study was conducted. Isofemale colonizations of wild caught mosquitoes captured by landing catches were made for species confirmation and to determine the mosquito life cycle. Pupal morphology indicated all mosquitoes were An. campestris. During the late rainy season (October and November), An. campestris populations comprised 78.6% of all females captured by human landing catches and 7.1% of mosquitoes in a cow-baited trap. The biting activity cycle peaked between 2000 and 0100 hours and was highest (17.6 bites per person per hour) at 2300 hours. More An. campestris bit people indoors (nine bites per person per hour) than outdoors (four bites per person per hour). Immature An. campestris were found in ponds, swamps, rice-fields, puddles, marshes, ground pools, and pits with open sunlight to partial shade. The time from egg hatch to adult was 18-47 d and 14-22 d under laboratory (25.0-27.0 degrees C) and ambient (26-32 degrees C) conditions, respectively. The fecundity of An. campestris ranged from 173 to 311 eggs. Based on experimental infections, An. campestris was able to support the sporogonic cycle of P. vivax with 76.2 and 23.8% oocyst and sporozoite formation rate, respectively. An. campestris shows high potential as a malaria vector in Pa Rai.

Pyroclastic flow hazard assessment at Vesuvius (Italy) by using numerical modeling. II. Analysis of flow variables

The numerical simulations of pyroclastic flow propagation along the Vesuvius slopes, described in a companion paper (Todesco et al. 2002, this volume), are herein analyzed in terms of the local variables of the flow with the aim of assessing quantitatively pyroclastic flow hazard in the Vesuvian area. The analysis was carried out by determining the timewise behavior of selected hazard variables of the flow – such as density, velocity, temperature, dynamic pressure, and pressure perturbation – at various distances from the crater and in the proximity of ground level. Density, velocity, temperature, and pressure of the flow were directly computed by the model during a period of about 15 min. These variables were then used to estimate two additional variables: the dynamic pressure of the flow and the isotropic pressure variation with respect to the undisturbed atmospheric pressure. These two variables may be both critical for the assessment of damage produced by the flow on engulfed buildings and people indoors. Dynamic pressure is associated with the motion of the flow, whereas the isotropic pressure variation accounts for the large-scale dynamics of the process, including the effect of the weight of the flow and the propagation of pressure waves into the atmosphere. A post-processing of the time series produced led to the definition of peak curves of the main hazard variables as a function of distance from the vent. The results indicate that pyroclastic flow propagation is an unsteady process producing strongly transient stresses on the structures encountered. Mass flow-rate per unit angle of propagation of the flow is confirmed as the main parameter controlling the flow dispersal and, therefore, the intensity of dynamic pressure and isotropic pressure variation. For the worst case considered, i.e., a mass flow-rate of 5×107 kg s–1 spreading over a sector of 90°, the two contributions have a similar magnitude, with typical values ranging between 3 and 1 kPa in the medium (4 km) and distal (7.5 km) regions of the flow, respectively. For this case, no significant variations are predicted between the southern and northern axisymmetric profiles assumed. Production of missiles transported by the flow is expected to represent an additional significant hazard associated with the flows.

Designing a positioning system for finding things and people indoors

Despite extraordinary advances in Global Positioning System (GPS) technology, millions of square meters of indoor space are out of reach of Navstar satellites. Their signals, originating high above the Earth, are not designed to penetrate most construction materials, and no amount of technical wizardry is likely to help. So the greater part of the world's commerce, being conducted indoors, cannot be followed by GPS satellites. Here, the authors describe how tracking people and assets indoors has now moved from the realm of science fiction to reality, thanks to a radiofrequency identification technique now being introduced to the market.

Light Extinction by Fire Smokes

Visibility of escape routes is most important to guarantee the safety of people indoors during fires. In the case of a fire, visibility is strongly in fluenced by the smoke present in the room. In the present work, the extinction co efficient of the visible light has been experimentally measured in the presence of the smoke produced by four different test fires, named TF2, TF3, TF4, and TF5. Tests have been carried out in a specially suited test room in the Italian Fire De partment Research Center, provided with instruments to measure the optical density of smoke and the spectral extinction coefficient.

Some Observations on the Biting Behavior ofAnopheles gambiae s.s, Anopheles arabiensis, andAnopheles funestusand Their Implications for Malaria Control

Studies were carried out in three villages in western Kenya on the biting behavior ofAnopheles gambiae s.s., Anopheles arabiensis,andAnopheles funestus.Blood feeding behavior and departure from houses were studied under the impact of permethrin-impregnated eaves-sisal curtains. Only 2–13% of the female vector population was collected biting before 2200 hr. Over 90% of the villagers went to bed by 2100 hr.An. funestuswas 6.6–8.2 times more likely to bite people indoors than outdoors, whileAn. gambiae s.l.females were only 2 times as likely. Under the influence of permethrin-impregnated sisal curtains placed under the eaves of village houses, there was a marked egress of blood-fedAn. funestusandAn. gambiae s.s.Permethrin seems to have induced exophily of half-gravid femaleAn. gambiae s.s.WhileAn. gambiae s.s.remained highly anthropophagic under the impact of permethrin,An. funestusshifted to feeding more on cattle.An. arabiensiswere largely zoophilic. Our results underline the difficulties of controllingAn. gambiae s.s.,the principal African malaria vector. New strategies must be found to control this vector