462 research outputs found
Some Theoretical Aspects of Car Trips within Urban Area
OD trips in urban area are described by an ergodic Markov chain for each kind of car and have a certain steady pattern for each trip. The pattern of OD trips is effected by the total number of cars independently of initial distribution of registered cars and strongly by the transition probabilities from zone to zone and their limiting vector. The limiting vector make a display of potentiality of generating trips for each kind of car. In estimating future traffic volume, it plays an important role in determination of the pattern of car trips, because the limiting vector is given by land use planning. Transition probabilities are introduced from maximizing entropy per unit time under the fixed limiting vector. Thus OD trips in the future are easily estimated, using the transition probabilities. It is proved that car trips estimated by maximizing entropy are symmetrical
Slowly Decaying Ringdown of a Rapidly Spinning Black Hole: Probing the No-Hair Theorem by Small Mass-Ratio Mergers with LISA
The measurability of multiple quasinormal (QN) modes, including overtones and
higher harmonics, with the Laser Interferometer Space Antenna is investigated
by computing the gravitational wave (GW) signal induced by an intermediate or
extreme mass ratio merger involving a supermassive black hole (SMBH). We
confirm that the ringdown of rapidly spinning black holes are long-lived, and
higher harmonics of the ringdown are significantly excited for mergers of small
mass ratios. We investigate the measurability and separability of the QN modes
for such mergers and demonstrate that the observation of GWs from rapidly
rotating SMBHs has an advantage for detecting superposed QN modes and testing
the no-hair theorem of black holes.Comment: 8 pages, 8 figures, version accepted for publication in PR
Detached and Continuous Circumstellar Matter in Type Ibc Supernovae from Mass Eruption
Some hydrogen-poor supernovae (SNe) are found to undergo interaction with
dense circumstellar matter (CSM) that may originate from mass eruption(s) just
prior to core-collapse. We model the interaction between the remaining star and
the bound part of the erupted CSM that eventually fall back to the star. We
find that while fallback initially results in a continuous CSM down to the
star, feedback processes from the star can push the CSM to large radii of
cm from several years after the eruption. In the latter case,
a tenuous bubble surrounded by a dense and detached CSM extending to cm is expected. Our model offers a natural unifying explanation for
the diverse CSM structures seen in hydrogen-poor SNe, such as Type Ibn/Icn SNe
that show CSM signatures soon after explosion, and the recently discovered Type
Ic SNe 2021ocs and 2022xxf ("the Bactrian") with CSM signatures seen only at
late times.Comment: 6 pages, 4 Figures. To be submitted to PASJ letters in the weeken
The Development of Trip Chaining Approaches in Travel Demand Modelling
The purpose of this paper is to incorporate trip chaining into travel demand analysis, and also to develop a model for an estimation of trip generation. Before the discussion on the model formulation, a brief historical review of trip chaining approaches is presented, and some validations of those approaches are explored. The model proposed here is able to explain the derived nature of travel demand due to various kinds of business activities in a metropolitan area. One particular concern is to describe the cycle-sojourn zone distribution, which plays an important role for generating a sequence of business trips. In this model, the cycle-sojourn zone distribution is formulated by applying an entropy maximizing distribution model of the gravity type. From its application, it can be found that this model is useful for representing business trip chaining behaviours in a single day
Analysis of the Image for Landscape of Port City
The purpose of this study is to obtain basic information available to make a new design concept at the first stage of landscape planning. Recently, with the large change of waterfront spaces, urban environments around port cities are getting more serious in Japan. So it is nesessary to begin planning to recreate the landscapes and facilities. However in this case we should consider the people's image and impression on curtural climate or environments to make fascinating townscapes. We sconsider two positions of people's image denned. One is the Media Image, and the other is the Residents' Image. Many current topics on tourist resorts or fascinating landscapes have been usually reported by visual and linguistic mass media in Japan. Many people form their images on townscapes without real experience. This image is called the Media Image and represents the external people's hope for spaces. On the other hand, the internal residents in the port city form their image by real experience or influence on their lives. This image is defined as the Residents' Image. Through a psychological experiment under the stimulus of visual media, this study specifies basic characteristics of the visual landscapes at representative port cities in Japan by comparing the two images
A Safety Index for Traffic with Linear Spacings
The authors have tried to improve the traffic dynamic theory of Prof. Pipes and have found the fundamental equation of traffic dynamics for a case in which the velocity of the following vehicle is determined not only by the space between following and lead cars but also by the velocity of the lead car. The safety of the following car with respect to rear end collision when the lead car is in sinusoidal motion is quantified by introducing a safety index. At the same time, the authors describe the stability of the indicial response of the following car, and the stability of the propagation of a sinusoidal disturbance down a line of cars
Precursors of Supernovae from Mass Eruption: Prospects for Early Warning of Nearby Core-collapse Supernovae
Recent observations of a large fraction of Type II supernovae show traces of
dense circumstellar medium (CSM) very close to the progenitor star. If this CSM
is created by eruptive mass loss several months before core-collapse, the
eruption itself may be visible as a precursor, helpful as an early warning of a
near-future supernova. Using radiation hydrodynamical simulations based on the
open-source code CHIPS, we theoretically model the emission from mass eruption
of a red supergiant star. We find that for a modest mass eruption the
luminosity is typically on the order of erg s, can last as
long as hundreds of days until the star explodes, and is mainly bright in the
infrared (from -9 to -11 mag around peak). We discuss observational strategies
to find these signatures from Galactic and local Type II supernovae.Comment: 15 pages (main text 10p), 9 figures. Expanded parameter study in
Appendix, conclusions unchanged. Accepted by Ap
A Photon Burst Clears the Earliest Dusty Galaxies: Modelling Dust in High-redshift Galaxies from ALMA to JWST
The generation and evolution of dust in galaxies are important tracers for
star formation, and can characterize the rest-frame ultraviolet to infrared
emission from the galaxies. In particular understanding dust in high-redshift
galaxies are important for observational cosmology, as they would be necessary
to extract information on star formation in the early universe. We update the
public semi-analytical model A-SLOTH (Ancient Stars and Local Observables by
Tracing Halos) to model the evolution of dust, focusing on high-redshift
star-forming galaxies with stellar masses of --
observed by ALMA () and JWST (). We find that these
galaxies should qualitatively differ in their star formation properties; while
the samples in ALMA are explained by dust growth in normal star-forming
galaxies, the lack of dust in the samples by JWST requires dust ejection by
radiation pressure due to recent highly efficient star-formation within a few
10 Myr, with order 100 times higher efficiency than normal galaxies calibrated
by A-SLOTH. Depending on where the JWST galaxies locate on the luminosity
function, their bursty star formation histories inferred from our model can
have impacts for rates of star formation, supernova explosion, stellar
feedback, and detectability of dusty, mature galaxies in the very early
universe.Comment: 13 pages, 7 figures. Revised after MNRAS referee report. Comments
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