An image of an area is given, and it is required to define the locations
of the area and of the photographing camera within some pre-defined scene,
as well as the camera parameters. The method of solution is as follows.
Details of the scene are extracted from a sequence of its images and fed
into a data base. The recognition system tries to identify the details
in the image and to obtain equations comprising parameters of the camera
and of the found details. The solution of the equations provides the required
data. The problem is generalized for sequences of images.
A telephone network is given with specified flows between each pair
of nodes. The problem is to efficiently cover the network by a set of rings
with specific properties, so that all flows are transferred through the
rings without exceeding their capacities. Criteria for efficiency are:
equipment cost and flexibility, namely the maximal ratio of the flow in
a ring and its capacity. A planning tool was constructed which allows the
user to define and edit a network with its pertinent data and obtain efficient
sets of rings and optimal sets of paths and flows.
An algorithm for image enhancement has been developed which considerably
improves the visual quality of video images. The algorithm combines an
adaptive brightness processing of obscure areas in the image and a sharpening
filtration procedure. The enhancement algorithm contains a mollifying (regularization)
component, in order to weaken the differentiation artifacts that are typical
for sharpening filters.
A smokestack of an electric power station usually emits droplets containing
toxic materials generated during combustion. The droplets formed inside
the stack result from complex hydrodynamic and thermal processes, such
as condensation on the stack wall and in the flow, deposition and flow
separation. The Israel Electric Corporation needed to specify requirements
to prospective stack constructors towards the construction of a new power
station. The project has provided adequate description of the main processes
with their possible scenarios, determined the basic factors responsible
for them and formulated the appropriate requirements. The following phase
will include expert evaluation and analysis of proposals put forward by
the firms bidding for the contract.
Differential equations have been derived and a program has been written
to simulate the motion of a Maneuvering Projectile in a vertical plane
with account for nonlinearities in aerodynamic forces. Numerical analysis
has been carried out of the motion with a given control. The effect of
the control parameters on the rocket's eigenfrequencies has been studied
numerically aiming at evaluating the effect of measurement errors on final
deviation.
Our contribution to the well-known problem of straight lines recognition
is the development of two new methods accommodating noisy distorted images
and weakly curved lines: (1) the weighted Hough transform - a more robust
version of Hough's known method, and (2) the method of slide correlation,
based on the invariance of a straight line with respect to translations
parallel to it. Both methods have been implemented in a two-stage algorithm
for line recognition. At the initial stages the image is subdivided into
cells in which local line segments are found. These are subsequently linked
into global lines.
While most aesthetic properties may be studied only by highly skilled specialists or
artists, some basic aesthetic features may be expressed in mathematical form. Computer
evaluation of image aesthetic quality is especially important for automatic page layout
practiced in multimedia and publishing process, for at the present time only user evaluation is
available. Such basic aesthetic criteria were worked out to evaluate numerically the color
distribution quality of any image. These criteria realize in a simple mathematical form some
well known traditional composition laws (color balance).
When printing large high quality posters (1.6 x 2.5 m) by means of a printer with more than
hundred printing heads a characteristic problem is encountered: bright strips emerge in the
printing direction. This phenomenon is called “bending”. These strips are especially visible on
poster regions with constant color. The problem is to change the command to the printer in
order to avoid the bending strips. In other words any image sent to printer by computer has to
be distorted in such a way that the given non-ideal printer will produce the original
not-distorted image. A systematic mathematical study of input-output relations was carried out
using harmonic analysis and fast Fourier transform. A significant improvement of the printer
performance was attained.
A thermoplastic-jet model of penetration has been developed, taking
into account the resistance of projectile and target materials to deformations
occurring during the penetration process. The model determines all significant
parameters of penetration, including the crater dimensions.
A flexible multi-ply plate under a concentrated impact exhibits elastic
and failure waves. A model for these phenomena has been developed and the
influence of parameters of the composite on the stopping power has been
determined. The dynamics and fracture of a viscoelastic discrete lattice
have been analytically and numerically investigated.
A model has been constructed to study the weld process and to assess
the weld strength as a function of the material and of the structural parameters
of the welding device. A series of mathematical models has been developed
to analyze the influence of viscoelasticity and viscoplasticity of welded
materials on the properties of joints. In particular, the effects of the
cooling program and material aging have been studied both analytically
and numerically. The results of the numerical simulation have been compared
with available experimental data and good correspondence was found.
MOST - Vortex Chambers
Design work is under way to develop a compact cyclone for air purification
with enhanced efficiency relative to existing cyclones. In order to raise
the quality of purification and to achieve separation of small-size particles
(down to several mm) an original scheme has been proposed for moistening
the air flow, which is effectively achieved by the injection of water.
The proposed method of air moistening is theoretically studied and the
hydrodynamic conditions are determined providing for its optimal effectiveness.
The effect of deflection from coaxiality of the cyclone outlet nozzle on
the degree of purification and on the cyclone efficiency is theoretically
evaluated. Design specifications have been worked out for a test device
for air moistening according to the proposed scheme, and a sample device
has been manufactured. Vortex chambers of two different designs are also
considered theoretically and numerically - with inserted perforated and
non-perforated tubes for particle separation. Solution stability and quasi-steady-state
solutions are studied for an equation system describing the motion of dust
particles in vortex chambers.
The Israeli railroads company needs a planning tool to schedule the
transportation of empty freight cars so as to enable the daily realization
of freight transportation plans. Three problems have been investigated:
(1) an algorithm to select which transportation orders to satisfy from
among the incoming stream considering the expected revenue and some administrative
constraints; (2) application of the transportation problem with restrictions
to determine the number of cars to be transported from points where they
are found in the evening to points where they are needed next morning;
(3) a combination of optimization and heuristic methods to plan the transportation
by existing trains. An appropriate scheme for data collection and instruction
distribution has been designed.
Pelephone company faces extensive fraud activity in various aspects,
one of which is cloning of cellular handsets. A comprehensive concept for
an anti-fraud system has been designed and several basic algorithms have
been constructed and implemented in the company’s information systems.
The set includes an advanced algorithm for detecting and evaluating the
full extent of events of overlapping calls, statistical algorithms to assess
the number of cloning devices from the behavior of traffic, a sophisticated
algorithm to detect pairs of calls which are inconsistent by space-time
considerations, methods for on-line data collection for the algorithms.
Some new and surprising loss estimates have been performed.