How do elderly pedestrians perceive hazards in the street? - An initial investigation towards development of a pedestrian simulation that incorporates reaction of various pedestrians to environments

In order to evaluate the accessibility of street and transport environments, such as railway stations, we are now developing a pedestrian simulation that incorporates elderly and disable pedestrians and their interaction with various environments including hazards on the street. For this development, it is necessary to understand how elderly and disabled pedestrians perceive hazards in the street and transport environments. Many elderly people suffer from some visual impairment. A study in the UK suggested 12% of people aged 65 or over have binocular acuity of 6/18 or less (Van der Pols et al, 2000). It should be noted that a quarter of the UK population will be aged 65 or over by 2031 (The Government Actuary's Department, 2004). Because of age-related changes of visual perception organs, elderly people suffer not only visual acuity problems but also other forms of visual disabilities, such as visual field loss and less contrast sensitivity. Lighting is considered to be an effective solution to let elderly and disable pedestrians perceive possible hazards in the street. Interestingly, British Standards for residential street lighting have not considered lighting needs of elderly pedestrians or pedestrians with visual disabilities (e.g. Fujiyama et al, 2005). In order to design street lighting that incorporates elderly and visually disabled pedestrians, it would be useful to understand how lighting improves the perception of hazards by elderly and disable pedestrians. The aim of this paper is to understand how elderly pedestrians perceive different hazards and to address issues to be investigated in future research. This paper focuses on fixation patterns of elderly pedestrians on different hazards in the street under different lighting conditions. Analysing fixation patterns helps us understand how pedestrians perceive environments or hazards (Fujiyama, 2006). This paper presents the initial results of our analysis of the eye tracker data of an ordinary elderly participant

Mapping social vulnerability to flood hazard in Norfolk, England

In this paper, we present a method to assess social vulnerability through the creation of an Open Source Vulnerability Index (OS-VI). The OS-VI provides context to environmental hazards and allows NGOs and local agencies to better tailor services and provide targeted pre-emptive vulnerability reduction and resilience-building programmes. A deductive indicator-based approach is utilised to incorporate a wide range of vulnerability indicators known to influence vulnerability. Unlike many vulnerability indices, the OS-VI incorporates flood risk as well as the loss of capabilities and the importance of key services (health facilities and food stores) through the measurement of accessibility when determining an area's level of social vulnerability. The index was developed using open-source mapping and analysis software and is composed completely of open-source data from national data sets. The OS-VI was designed at the national level, with data for all proxy indicators available across the entirety of England and Wales. For this paper, a case study is presented concerned with one English county, Norfolk

Pedestrian level of interaction on platform conflict areas by real-scale laboratory experiments

The objective of this work was to develop a new method to measure the interaction of passengers boarding and alighting at metro stations. This method included the Level of Interaction (LOI) as more precise indicator compared to the Level of Service (LOS). The method consisted of building a mock-up of a metro car and a series of simulation experiments in University College London’s Pedestrian Accessibility Movement Environmental Laboratory (PAMELA) based on observation at two London Underground station. This mock-up included Platform Edge Doors (PEDs) and a new space defined as Platform Conflict Area in front of the train doors in which the density of passengers was high. Results of the laboratory experiments were expressed according to the types of queues, formation of lanes, density by layer, and distance between passengers, in which the interaction followed a Logarithmic Distribution and no statistical differences were found with PEDs. These results are helpful for traffic engineers and policy makers to measure the interaction and use the LOI as a new indicator for the design of spaces in metro systems

Charge Segregation, Cluster Spin-Glass and Superconductivity in La1.94Sr0.06CuO4

A 63Cu and 139La NMR/NQR study of superconducting (Tc=7 K) La1.94Sr0.06CuO4 single crystal is reported. Coexistence of spin-glass and superconducting phases is found below ~5 K from 139La NMR relaxation. 63Cu and 139La NMR spectra show that, upon cooling, CuO2 planes progressively separate into two magnetic phases, one of them having enhanced antiferromagnetic correlations. These results establish the AF-cluster nature of the spin-glass. We discuss how this phase can be related to the microsegregation of mobile holes and to the possible pinning of charge-stripes.Comment: 4 pages. Modified manuscript with clarification

Nuclear spin-spin coupling in La_{2-x}Sr_{x}CuO_{4} studied by stimulated echo decay

We have performed copper NQR experiments in high temperature superconductors YBa_{2}Cu_{4}O_{8}, YBa_{2}Cu_{3}O_{7}, and La_{2-x}Sr_{x}CuO_{4} (x=0.12 and 0.15), using the stimulated echo technique. The stimulated echo intensity is analyzed by a model that includes the spin-lattice relaxation process (T_ {1 }-process) and the fluctuating local field due to nuclear spin-spin coupling. The model gives quantitative account of the experimental results in Y-based compounds using the known values of 1/T_{1} and 1/T_{2G}, the gaussian decay rate of the spin echo intensity. The same model applied to LSCO enables us to extract the value of T_{2G}. Our results indicate that T_{1}T/T_{2G} is independent of temperature, implying that the dynamic exponent is one in La_{2-x}Sr_{x}CuO_{4}.Comment: 14 pages, 11 fugures, The bibliography field is correcte

Nonbonding oxygen holes and spinless scenario of magnetic response in doped cuprates

Both theoretical considerations and experimental data point to a more complicated nature of the valence hole states in doped cuprates than it is predicted by Zhang-Rice model. Actually, we deal with a competition of conventional hybrid Cu 3d-O 2p $b_{1g}\propto d_{x^2 -y^2}$ state and purely oxygen nonbonding state with $e_{u}x,y \propto p_{x,y}$ symmetry. The latter reveals a non-quenched Ising-like orbital moment that gives rise to a novel spinless purely oxygen scenario of the magnetic response in doped cuprates with the oxygen localized orbital magnetic moments of the order of tenths of Bohr magneton. We consider the mechanism of ${}^{63,65}$Cu-O 2p transferred orbital hyperfine interactions due to the mixing of the oxygen O 2p orbitals with Cu 3p semicore orbitals. Quantitative estimates point to a large magnitude of the respective contributions both to local field and electric field gradient, and their correlated character.Comment: 7 pages, 1 figur

Charge order, superconductivity, and a global phase diagram of doped antiferromagnets

We investigate the interplay between lattice-symmetry breaking and superconducting order in a two-dimensional model of doped antiferromagnets, with long-range Coulomb interactions and Sp(2N) spin symmetry, in the large-N limit. Our results motivate the outline of a global phase diagram for the cuprate superconductors. We describe the quantum transitions between the phases, the evolution of their fermion excitation spectrum, and the experimental implications.Comment: 4 pages, 4 figs, final version as publishe

Pseudogap Induced Antiferromagnetic Spin Correlation in High-Temperature Superconductors

The pseudogap phenomena observed on cuprate high temperature superconductors are investigated based on the exact diagonalization method on the finite cluster t-J model. The results show the presence of the gap-like behavior in the temperature dependence of various magnetic properties; the NMR relaxation rate, the neutron scattering intensity and the static susceptibility. The calculated spin correlation function indicates that the pseudogap behavior arises associated with the development of the antiferromagnetic spin correlation with decreasing the temperature. The numerical results are presented to clarify the model parameter dependence, that covers the realistic experimental situation. The effect of the next-nearest neighbor hopping $t'$ is also studied.Comment: 7 pages, Revtex, with 10 eps figures, to appear in J. Phys. Soc. Jpn. (Vol. 70, No. 1

Nuclear Spin Relaxation in Hole Doped Two-Leg Ladders

The nuclear spin-lattice relaxation rate ($1/T_{1}$) has been measured in the single crystals of hole doped two-leg ladder compounds Sr$_{14-x}$Ca$_{x}$Cu$_{24}$O$_{41}$ and in the undoped parent material La$_6$Ca$_8$Cu$_{24}$O$_{41}$. Comparison of $1/T_{1}$ at the Cu and the two distinct oxygen sites revealed that the major spectral weight of low frequency spin fluctuations is located near $q \sim (\pi, \pi)$ for most of the temperature and doping ranges investigated. Remarkable difference in the temperature dependence of $1/T_1$ for the two oxygen sites in the heavily doped $x$=12 sample revealed reduction of singlet correlations between two legs in place of growing antiferromagnetic correlations along the leg direction with increasing temperature. Such behavior is most likely caused by the dissociation of bound hole pairs.Comment: 4 pages. to appear in J. Phys. Soc. Jpn. Vol. 6

Estimation of the passenger space in the boarding and alighting at metro stations

Platform edge doors (PEDs) have been used in various metro stations to improve safety and ventilation conditions, however limited research has been done to estimate the passenger space (PS) in the boarding and alighting process when PEDs are installed. The aim of this study was to estimate the space needed for boarding and alighting at metro stations. The method was based on a mock-up carriage and the relevant portion of the platform at University College London´s Pedestrian Accessibility Movement Environmental Laboratory (PAMELA), in which different load scenarios of boarding and alighting were conducted. The scenarios were based in a preliminary analysis observed at Westminster Station, in which PEDs are installed. To obtain the position of each passenger on the platform a tracking tool was used. The hypothesis of this research was that PS for alighting passengers can be represented as an asymmetrical ellipse, in which the longitudinal and lateral radii changed according to the negotiation with other passengers alighting or waiting on the platform to board the train. Therefore, there is a relationship between PS and the level of interaction, which suggests that passengers adjust their PS to avoid collision. This research can be used by traffic engineers to estimate PS of passengers boarding and alighting when PEDs are used. This in turn can help in designing the platform train interface (PTI) and platforms at transport infrastructures