2,724 research outputs found
Game prototype for understanding safety issues of life boat launching process.
Novel advanced game techniques provide us with new possibilities to mimic a complicated training process, with the benefit of safety enhancement. In this paper, we design and implement a 3D game which imitates the lifeboat launching process. Lifeboat launching is such a complex but vital process which can on one side saving people's life on sea and on the other side associating many potential hazards. It involves both the tractor manoeuvres and boat operations. The primary objective of the game is to allow novices to better understand the sequence of the operations in launching process and manager the potential hazards happening during the launching. There is also great educational significance with the promotion of the game to the general public for enhanced awareness of safety issues. The key modules of the game are designed based on physical simulation which gives the players enhanced plausible cognition and enjoyable interaction
Tomonaga-Luttinger features in the resonant Raman spectra of quantum wires
The differential cross section for resonant Raman scattering from the
collective modes in a one dimensional system of interacting electrons is
calculated non-perturbatively using the bosonization method. The results
indicate that resonant Raman spectroscopy is a powerful tool for studying
Tomonaga-Luttinger liquid behaviour in quasi-one dimensional electron systems.Comment: 4 pages, no figur
Spin dynamics of a trapped spin-1 Bose Gas above the Bose-Einstein transition temperature
We study collective spin oscillations in a spin-1 Bose gas above the
Bose-Einstein transition temperature. Starting from the Heisenberg equation of
motion, we derive a kinetic equation describing the dynamics of a thermal gas
with the spin-1 degree of freedom. Applying the moment method to the kinetic
equation, we study spin-wave collective modes with dipole symmetry. The dipole
modes in the spin-1 system are found to be classified into the three type of
modes. The frequency and damping rate are obtained as functions of the peak
density. The damping rate is characterized by three relaxation times associated
with collisions.Comment: 19 pages, 5 figur
Atomic position localization via dual measurement
We study localization of atomic position when a three-level atom interacts
with a quantized standing-wave field in the Ramsey interferometer setup. Both
the field quadrature amplitude and the atomic internal state are measured to
obtain the atomic position information. It is found that this dual measurement
scheme produces an interference pattern superimposed on a diffraction-like
pattern in the atomic position distribution, where the former pattern
originates from the state-selective measurement and the latter from the field
measurement. The present scheme results in a better resolution in the position
localization than the field-alone measurement schemes. We also discuss the
measurement-correlated mechanical action of the standing-wave field on the atom
in the light of Popper's test.Comment: 6.5 pages and 5 figure
Order parameter model for unstable multilane traffic flow
We discuss a phenomenological approach to the description of unstable vehicle
motion on multilane highways that explains in a simple way the observed
sequence of the phase transitions "free flow -> synchronized motion -> jam" as
well as the hysteresis in the transition "free flow synchronized motion".
We introduce a new variable called order parameter that accounts for possible
correlations in the vehicle motion at different lanes. So, it is principally
due to the "many-body" effects in the car interaction, which enables us to
regard it as an additional independent state variable of traffic flow. Basing
on the latest experimental data (cond-mat/9905216) we assume that these
correlations are due to a small group of "fast" drivers. Taking into account
the general properties of the driver behavior we write the governing equation
for the order parameter. In this context we analyze the instability of
homogeneous traffic flow manifesting itself in both of the mentioned above
phase transitions where, in addition, the transition "synchronized motion ->
jam" also exhibits a similar hysteresis. Besides, the jam is characterized by
the vehicle flows at different lanes being independent of one another. We
specify a certain simplified model in order to study the general features of
the car cluster self-formation under the phase transition "free flow
synchronized motion". In particular, we show that the main local parameters of
the developed cluster are determined by the state characteristics of vehicle
motion only.Comment: REVTeX 3.1, 10 pages with 10 PostScript figure
Path finding strategies in scale-free networks
We numerically investigate the scale-free network model of Barab{\'a}si and
Albert [A. L. Barab{\'a}si and R. Albert, Science {\bf 286}, 509 (1999)]
through the use of various path finding strategies. In real networks, global
network information is not accessible to each vertex, and the actual path
connecting two vertices can sometimes be much longer than the shortest one. A
generalized diameter depending on the actual path finding strategy is
introduced, and a simple strategy, which utilizes only local information on the
connectivity, is suggested and shown to yield small-world behavior: the
diameter of the network increases logarithmically with the network size
, the same as is found with global strategy. If paths are sought at random,
is found.Comment: 4 pages, final for
Statistics of Wave Functions in Coupled Chaotic Systems
Using the supersymmetry technique, we calculate the joint distribution of
local densities of electron wavefunctions in two coupled disordered or chaotic
quantum billiards. We find novel spatial correlations that are absent in a
single chaotic system. Our exact result can be interpreted for small coupling
in terms of the hybridization of eigenstates of the isolated billiards. We show
that the presented picture is universal, independent of microscopic details of
the coupling.Comment: 4 pages, 2 figures; acknowledgements and references adde
Dynamic transition in driven vortices across the peak effect in superconductors
We study the zero-temperature dynamic transition from the disordered flow to
an ordered flow state in driven vortices in type-II superconductors. The
transition current is marked by a sharp kink in the
characteristic with a concomitant large increase in the defect concentration.
On increasing magnetic field , the follows the behaviour of the
critical current . Specifically, in the peak effect regime
increases rapidly along with . We also discuss the effect of varying
disorder strength on .Comment: 4 pages, 4 figure
Identifying the Technology Position on Patent Acquisition of Cardiovascular Stent by Complementarity and Supplementary Knowledge
[[abstract]]The most common way for an organization to expand its innovation capability is to acquire technological patent. Consequently, it is an important issue for firms to identify and estimate the target patent. Before acquiring, firms also have to make sure whether the target patents is matching the strategic purpose, and whether the target patent is suitable for the adopting after acquiring. And the result of patent citation analysis can be referred for estimating target patent as the result reveals the technology relationship between firms, the market value of technologies and the technology development strategy. Moreover, technology network analysis can visualize the overall social structure of actors in the technology network and illuminate their relationships and roles. However, few scholars have examined the relative positions of firms in technology networks from the viewpoint of individual social networks. This research uses the idea of the "ego-network", defining the firm's core technology patent portfolio as "ego" while patents which directly cite core patents are defined as the "neighborhood. The purpose of this research is to understand how the firm, through patent transfers, alters its technology position and performs inductive analysis as a reference for future changes in its patent portfolio strategies. The results of this research demonstrate that irrespective of patent transfer strategy, the relative position of firms in the technology network is displaced by patent transfers. By dividing the trajectory of displacement into quadrants the data set may be named as pioneers, leaders, followers, and laggards. And the result shows firms may exit markets, reduce internal subdivisions, carry out cost control, or sell off patents, moving their position to the left or downward and making them followers or laggards. By the same token, when firms enter a new technology area or market, increase their technological capabilities, or acquire technology patents, their position shits to the right or downward, and they become leaders or pioneers.[[notice]]補正完
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