A precision sidereal telescope drive based on a solar time crystal clock

A requirement arose for a sidereal drive for a small microwave radiometer on an equatorial mount, the equipment to run unattended to a precision of about 2 minutes in hour angle over a 7-day period. The installation already included a solar-time crystal clock based on a IO MHz oscillator (type HCD 25), which through decade scalers could easily be arranged to operate a standard 50 Hz synchronous motor which would drive the mounting at one revolution per solar day. However, no suitable gearing was available to generate the required sidereal rate

A Search for Isolated Microwave Pulses from the Perseus Cluster of Galaxies

The paper describes a search for prompt microwave emissions from supernovae in the central region of the Perseus cluster of galaxies, using a coincidence technique involving five tracking radiometers located at widely spaced sites. No coincidences were found between January and December, 1973, and no supernovae were reported during this period from the optical surveys, in that region of sky

An Upper Limit to Microwave Pulse Emission at the Onset of a Supernova

This paper reports an upper limit at 10 GHz of 4 x 10^(43) erg in a 40 MHz bandwidth for the microwave pulse emission at the onset of an optically observed supernova

The Fundamental Diagram of Pedestrian Movement Revisited

The empirical relation between density and velocity of pedestrian movement is not completely analyzed, particularly with regard to the `microscopic' causes which determine the relation at medium and high densities. The simplest system for the investigation of this dependency is the normal movement of pedestrians along a line (single-file movement). This article presents experimental results for this system under laboratory conditions and discusses the following observations: The data show a linear relation between the velocity and the inverse of the density, which can be regarded as the required length of one pedestrian to move. Furthermore we compare the results for the single-file movement with literature data for the movement in a plane. This comparison shows an unexpected conformance between the fundamental diagrams, indicating that lateral interference has negligible influence on the velocity-density relation at the density domain $1 m^{-2}<\rho<5 m^{-2}$. In addition we test a procedure for automatic recording of pedestrian flow characteristics. We present preliminary results on measurement range and accuracy of this method.Comment: 13 pages, 9 figure

Transportation research needs and issues for Chinese agriculture

Interprovincial circulation of grain and wholesale markets in China / Wu Shuo -- Inter-state/province grain transportation in the U.S. and China / Tenpao Lee, Robert J. Hauser, Stanley R. Thompson, and Barbara J. Hrutka -- Methodology and data systems for study of transportation / Won W. Koo and Jerry Fruin -- An application of a spatial equilibrium model to analyze the impact on China's trade of a policy change / Shwu-Eng H. Webb, Catherine K. Halbrendt, Rajaram Gana, and Francis Tuan -- Possible Joint Chinese and U.S. grain transportation and distribution research opportunities / Roland R. Robinson and Donald W. Larson -- Transportation research needs and issues for Chinese agriculture: discussion of session presentations / Dale G. Anderso

Enhanced empirical data for the fundamental diagram and the flow through bottlenecks

In recent years, several approaches for modelling pedestrian dynamics have been proposed and applied e.g. for design of egress routes. However, so far not much attention has been paid to their 'quantitative' validation. This unsatisfactory situation belongs amongst others on the uncertain and contradictory experimental data base. The fundamental diagram, i.e. the density-dependence of the flow or velocity, is probably the most important relation as it connects the basic parameter to describe the dynamic of crowds. But specifications in different handbooks as well as experimental measurements differ considerably. The same is true for the bottleneck flow. After a comprehensive review of the experimental data base we give an survey of a research project, including experiments with up to 250 persons performed under well controlled laboratory conditions. The trajectories of each person are measured in high precision to analyze the fundamental diagram and the flow through bottlenecks. The trajectories allow to study how the way of measurement influences the resulting relations. Surprisingly we found large deviation amongst the methods. These may be responsible for the deviation in the literature mentioned above. The results are of particular importance for the comparison of experimental data gained in different contexts and for the validation of models.Comment: A contribution to: Pedestrian and Evacuation Dynamics 2008 (Springer) 12 pages, 7 figure

Pedestrian, Crowd, and Evacuation Dynamics

This contribution describes efforts to model the behavior of individual pedestrians and their interactions in crowds, which generate certain kinds of self-organized patterns of motion. Moreover, this article focusses on the dynamics of crowds in panic or evacuation situations, methods to optimize building designs for egress, and factors potentially causing the breakdown of orderly motion.Comment: This is a review paper. For related work see http://www.soms.ethz.c

Engineering egress data considering pedestrians with reduced mobility

To quantify the evacuation process, evacuation practitioners use engineering egressdata describing the occupant movement characteristics. These data are typicallybased to young and fit populations. However, the movement abilities of occupantswho might be involved in evacuations are becoming more variable—with the buildingpopulations of today typically including increasing numbers of individuals: withimpairments or who are otherwise elderly or generally less mobile. Thus, there willbe an increasing proportion of building occupants with reduced ability to egress. Forsafe evacuation, there is therefore a need to provide valid engineering egress dataconsidering pedestrians with disabilities. Gwynne and Boyce recently compiled aseries of data sets related to the evacuation process to support practitioner activitiesin the chapter Engineering Data in the SFPE Handbook of Fire Protection Engineering.This paper supplements these data sets by providing information on and presentingdata obtained from additional research related to the premovement and horizontalmovement of participants with physical-, cognitive-, or age-related disabilities. Theaim is to provide an overview of currently available data sets related to, and keyfactors affecting the egress performance of, mixed ability populations which could beused to guide fire safety engineering decisions in the context of building design

Intelligent evacuation management systems: A review

Crowd and evacuation management have been active areas of research and study in the recent past. Various developments continue to take place in the process of efficient evacuation of crowds in mass gatherings. This article is intended to provide a review of intelligent evacuation management systems covering the aspects of crowd monitoring, crowd disaster prediction, evacuation modelling, and evacuation path guidelines. Soft computing approaches play a vital role in the design and deployment of intelligent evacuation applications pertaining to crowd control management. While the review deals with video and nonvideo based aspects of crowd monitoring and crowd disaster prediction, evacuation techniques are reviewed via the theme of soft computing, along with a brief review on the evacuation navigation path. We believe that this review will assist researchers in developing reliable automated evacuation systems that will help in ensuring the safety of the evacuees especially during emergency evacuation scenarios

Spatial layout planning in sub-surface rail station design for effective fire evacuation

The London Underground network is a crucial part of the transportation system in one of only four ‘Alpha’ world cities. The other three – Paris, New York and Tokyo – also have such sub-surface railway transport systems that may benefit from this shape grammar station design process in a future research proposal. In London’s case, the passenger flow rates are the underlining factor in sizing infrastructure where passengers have access – it is therefore this criterion that provides the basis for the shape grammar formulation for the largest, oldest and one of the most complex underground systems in the world. The research aims to improve passenger fire evacuation times, with due cognisance of the growth of numbers using the system, and its present susceptibility to terrorist attacks taken into account. The proposed shape grammar approach will provide for generation of spatial layouts, based upon visual rules of shape recognition, replacement / union, their connectivity and spatial relationships. The paper concentrates on definition and implementation of novel shape grammar design rules that incorporate station planning design knowledge, and in particular also discusses designers’ fire risk assessment approach and related knowledge that is also needed to produce credible station design solutions. Development, to date, of the proposed artificially intelligent CAD environment is also described along with parallel theoretical research. The proposed CAD interface provides familiarity to the designer and avoids incompatibility issues regarding drawing exchange format between various software systems. The shape grammar layouts produced will be tested in SIMULEX, a commercially available evacuation package, and be compared against ‘traditionally’ designed layouts to demonstrate improvements of preliminary ‘reference’ designs, which follow the standard London Underground design process as a later stage of this research