23,839 research outputs found
How can you estimate the value of a bus service? Evaluating buses in tourist areas
Bus services are currently threatened with cuts to reduce local government spending. Services provided for leisure activities in rural areas are particularly at risk as leisure travel is seen as less important than utility travel and the people using the buses are often from outside the area. This paper reports the findings of an ESRC funded project monitoring the benefits of such services and how their benefits to the area and passengers can be quantified. Although the goals of reducing car use, increasing social inclusion and access to areas of recreation, generating local spending and improving health and well-being are largely shared by different organisations, the project found very different priorities among stakeholders. Also, value for money was not the only criterion when budgets were allocated
Design and implementation of a microcomputer-based user interface controller for bursted data communications satellite ground terminals
The NASA Lewis Research Center is developing a laboratory-based satellite communications test bed for evaluation of state-of-the-art communications hardware and systems. Most of the digital components of the ground terminals are being constructed in-house at NASA Lewis. One of the ground terminal subsystems, the user interface controller, controls the connection and disconnection of all users to the communication network. The role of the user interface controller in the ground terminal is described and the design and implementation of the microcomputer-based subsystem is discussed
Travel Disruption: Three Case Studies
This report draws together the findings of three studies of travel disruption and its impacts on travellers: the volcanic ash cloud which disrupted aviation in Europe in 2010, the loss of road bridges between November 2009 and April 2010 at Workington, Cumbria and the severe winter weather across the UK in the winter of 2010-2011. It proposes a six phase cycle: normality, when transport provision matches expectations drawn from experience, tickets, timetables, etc;, disruption, when the transport provision fails to meet expectations; touching the new context when travellers seek to assess how the changed conditions affect their travel plans; the revised plan, when travellers make new plans on the basis of what they know about the context, the consequences, which includes counting the cost of changed travel plans in terms of extra expenditure of time, money, effort, prolonged absences as well as any benefits emanating from the experience; reflection and incorporation whereby the experience of disruption is assimilated int the new normality; this can include trust of agents, information, travelling more prepared for disruption or being aware of new channels of information or help
Galactic masers and the Milky Way circular velocity
Masers found in massive star-forming regions can be located precisely in
six-dimensional phase space and therefore serve as a tool for studying Milky
Way dynamics. The non-random orbital phases at which the masers are found and
the sparseness of current samples require modeling. Here we model the
phase-space distribution function of 18 precisely measured Galactic masers,
permitting a mean velocity offset and a general velocity dispersion tensor
relative to their local standards of rest, and accounting for different pieces
of prior information. With priors only on the Sun's distance from the Galactic
Center and on its motion with respect to the local standard of rest, the maser
data provide a weak constraint on the circular velocity at the Sun of V_c = 246
+/- 30 km/s. Including prior information on the proper motion of Sgr A* leads
to V_c = 244 +/- 13 km/s. We do not confirm the value of V_c \approx 254 km/s
found in more restrictive models. This analysis shows that there is no conflict
between recent determinations of V_c from Galactic Center analyses, orbital
fitting of the GD-1 stellar stream, and the kinematics of Galactic masers; a
combined estimate is V_c = 236 +/- 11 km/s. Apart from the dynamical
parameters, we find that masers tend to occur at post-apocenter,
circular-velocity-lagging phases of their orbits.Comment: ApJ in pres
Digitally modulated bit error rate measurement system for microwave component evaluation
The NASA Lewis Research Center has developed a unique capability for evaluation of the microwave components of a digital communication system. This digitally modulated bit-error-rate (BER) measurement system (DMBERMS) features a continuous data digital BER test set, a data processor, a serial minimum shift keying (SMSK) modem, noise generation, and computer automation. Application of the DMBERMS has provided useful information for the evaluation of existing microwave components and of design goals for future components. The design and applications of this system for digitally modulated BER measurements are discussed
Real-time data compression of broadcast video signals
A non-adaptive predictor, a nonuniform quantizer, and a multi-level Huffman coder are incorporated into a differential pulse code modulation system for coding and decoding broadcast video signals in real time
Continued fractions for some transcendental numbers
We consider series of the form , where and the integer sequence satisfies a certain non-autonomous recurrence of second order, which entails that for n?1. It is shown that the terms of the sequence, and multiples of the ratios of successive terms, appear interlaced in the continued fraction expansion of the sum of the series, which is a transcendental number
Worthy is the Lamb: Pastoral Symbols of Salvation in Christian Art and Music
This paper examines the role of the lamb and the Good Shepherd as Christian symbols of atonement in art and music. Christians adopted the lamb as a religious symbol from ancient cultures and from Jewish sacrificial traditions. It reflects their understanding of how redemption is achieved. The author demonstrates that the lamb, as well as the Good Shepherd, became emblems commonly used by visual artists and composers to represent theories of atonement which were generally accepted during their own times, as well as those which had enjoyed popularity in the past. Significant works explored here which employ the lamb and Good Shepherd as iconic figures include early Christian funerary art, the Agnus Dei of the mass, the Easter Sequence, Hubert and Jan Van Eyck\u27s Ghent altarpiece, Matthias Grunewald\u27s Isenheim altarpiece, George Friderich Handel\u27s oratorio, Messiah, and many Christian hymns. Some of these artistic works are shown to represent more than one idea about atonement
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