36,437 research outputs found
Patent reform: a mixed blessing for the U.S. economy?
The 1980s represented a period of dramatic change in the design and enforcement of U.S. intellectual property law. Many of these changes were adopted in the hopes of stimulating private research and development and improving the technological competitiveness of American industries. This article examines the effects of an especially important aspect of these changes: many more inventions qualify for patent protection than before. While it seems logical that making patents easier to obtain will encourage more inventive activity, economic analysis reveals this is not always true, and it is less likely to be true in industries that innovate rapidly.Patents
Understanding new venture market application search processes: A propositional model.
Technology-based ventures are confronted with complex decisions on how to apply their technology platform in highly uncertain and ambiguous market environments. Based on four case studies, a dynamic decision model is developed in which we highlight the similarities between the search and learning processes in venture development contexts and in new product development contexts. This entrepreneurial search and learning process is understood as consisting of sequences of episodes – characterized by uncertainty and ambiguity - and scripts – i.e. approaches to market application search. The model implies that a venture's adaptability - i.e. its ability to move efficiently and effectively between these episodes and their related scripts - influences its survival.Case studies; Decision; Decisions; Learning; Market; Model; Processes; Product; Product development; Research; Sequences; Similarity; Studies; Technology; Uncertainty;
Digital IP Protection Using Threshold Voltage Control
This paper proposes a method to completely hide the functionality of a
digital standard cell. This is accomplished by a differential threshold logic
gate (TLG). A TLG with inputs implements a subset of Boolean functions of
variables that are linear threshold functions. The output of such a gate is
one if and only if an integer weighted linear arithmetic sum of the inputs
equals or exceeds a given integer threshold. We present a novel architecture of
a TLG that not only allows a single TLG to implement a large number of complex
logic functions, which would require multiple levels of logic when implemented
using conventional logic primitives, but also allows the selection of that
subset of functions by assignment of the transistor threshold voltages to the
input transistors. To obfuscate the functionality of the TLG, weights of some
inputs are set to zero by setting their device threshold to be a high .
The threshold voltage of the remaining transistors is set to low to
increase their transconductance. The function of a TLG is not determined by the
cell itself but rather the signals that are connected to its inputs. This makes
it possible to hide the support set of the function by essentially removing
some variable from the support set of the function by selective assignment of
high and low to the input transistors. We describe how a standard cell
library of TLGs can be mixed with conventional standard cells to realize
complex logic circuits, whose function can never be discovered by reverse
engineering. A 32-bit Wallace tree multiplier and a 28-bit 4-tap filter were
synthesized on an ST 65nm process, placed and routed, then simulated including
extracted parastics with and without obfuscation. Both obfuscated designs had
much lower area (25%) and much lower dynamic power (30%) than their
nonobfuscated CMOS counterparts, operating at the same frequency
How and why communications industry suppliers get “squeezed out” by outsourcing: cases, impact and the next phases
The communications systems,terminals,and service, industries, have undergone over the past ten years a significant technological internal evolution and external revolution at customer end (such as shifting to IP, wireless 3G and LTE evolutions, new terminals, broadband...). Very little management research has studied their survivability irrespective of changes in demand volumes, due to technological sourcing and outsourcing practices driven by other global industries serving as predators in view of the huge business potential of communications products and services. These other industries include computing software, semiconductor and contract manufacturing industries, many of with roots in emerging countries. This paper analyzes the implications of using in-sourced genuine non-proprietary open communications standards , of the wider use of in-sourced /purchased technologies ,and of outsourced contract manufacturing . The methodology used is equilibrium analyses from case analysis data. They show a trend towards active or passive knowledge leakage. Three specific areas will be mentioned as examples .The paper also shows the processes how eventually those industries in a later cycle bounce back.Communications industry; Communications industry suppliers; Business processes; Intellectual property; Technical competence; Customer bases
Monolithically integrated InAsSb-based nBnBn heterostructure on GaAs for infrared detection
High operating temperature i
nfrared
photo
detectors
with multi
-color function
that are
capable of monolithic
integration
are of increasing importance
in developing the next
generation
of
mid
-IR
imag
e sensors.
Applications of these sensors
include defense, medical diagnosis, environmental and
astronomical observations.
We
have
investigated a novel
InAsSb
-based nBnBn heterostructure that combines a state
-of-art
InAsSb nBn detector with
an
InAsSb/GaSb heterojuncti
on
detector
. At room temperature, r
educti
on
in the dark current
density of more than an order of magnitude
was
achieved
compared to
previously investigated
InAsSb/GaSb heterojunction
dete
ctors
.
Electrical
characterization
from
cryogenic
temperatures to roo
m temperature
confirmed that the nBnBn
device was diffusion limited
for temperature
s above 150K. O
ptical
measurements
demonstrated that the
nBnBn detector
was
sensitive in
both
the
SWIR and MWIR wavelength range at
room
temperature
. The specific
detectivity
(D*)
of the competed nBnBn
devices
was calculated to be
8.6
×
10
8
cm
·
Hz
1/2
W
-1
at 300K and
approximately 1.0
×
10
10
cm
·
Hz
1/2
W
-1
when cooled down to 200K
(with
0.3V reverse bias
and 1550nm illumination
). In addition,
all
photodetector layers were
grown monolithically on GaAs active
layers u
sing the interfacial misfit
array
growth
mode
. Our results
therefore pave the way
for the development of
new active pixel
designs for monolithically integrated mid
-IR imaging arrays
Hybrid and modular multilevel converter designs for isolated HVDC–DC converters
Efficient medium and high-voltage dc-dc conversion is critical for future dc grids. This paper proposes a hybrid multilevel dc-ac converter structure that is used as the kernel of dc-dc conversion systems. Operation of the proposed dc-ac converter is suited to trapezoidal ac-voltage waveforms. Quantitative and qualitative analyses show that said trapezoidal operation reduces converter footprint, active and passive components' size, and on-state losses relative to conventional modular multilevel converters. The proposed converter is scalable to high voltages with controllable ac-voltage slope; implying tolerable dv/dt stresses on the converter transformer. Structural variations of the proposed converter with enhanced modularity and improved efficiency will be presented and discussed with regards to application in front-to-front isolated dc-dc conversion stages, and in light of said trapezoidal operation. Numerical results provide deeper insight of the presented converter designs with emphasis on system design aspects. Results obtained from a proof-of-concept 1-kW experimental test rig confirm the validity of simulation results, theoretical analyses, and simplified design equations presented in this paper. - 2013 IEEE.Scopu
Investigation of FACTS devices to improve power quality in distribution networks
Flexible AC transmission system (FACTS) technologies are power electronic solutions
that improve power transmission through enhanced power transfer volume and stability,
and resolve quality and reliability issues in distribution networks carrying sensitive
equipment and non-linear loads. The use of FACTS in distribution systems is still in
its infancy. Voltages and power ratings in distribution networks are at a level where
realistic FACTS devices can be deployed. Efficient power converters and therefore loss
minimisation are crucial prerequisites for deployment of FACTS devices.
This thesis investigates high power semiconductor device losses in detail. Analytical
closed form equations are developed for conduction loss in power devices as a function
of device ratings and operating conditions. These formulae have been shown to predict
losses very accurately, in line with manufacturer data. The developed formulae enable
circuit designers to quickly estimate circuit losses and determine the sensitivity of those
losses to device voltage and current ratings, and thus select the optimal semiconductor
device for a specific application.
It is shown that in the case of majority carrier devices (such as power MOSFETs), the
conduction power loss (at rated current) increases linearly in relation to the varying rated
current (at constant blocking voltage), but is a square root of the variable blocking voltage
when rated current is fixed. For minority carrier devices (such as a pin diode or IGBT),
a similar relationship is observed for varying current, however where the blocking voltage
is altered, power losses are derived as a square root with an offset (from the origin).
Finally, this thesis conducts a power loss-oriented evaluation of cascade type multilevel
converters suited to reactive power compensation in 11kV and 33kV systems. The cascade
cell converter is constructed from a series arrangement of cell modules. Two prospective
structures of cascade type converters were compared as a case study: the traditional type
which uses equal-sized cells in its chain, and a second with a ternary relationship between
its dc-link voltages. Modelling (at 81 and 27 levels) was carried out under steady state
conditions, with simplified models based on the switching function and using standard
circuit simulators. A detailed survey of non punch through (NPT) and punch through
(PT) IGBTs was completed for the purpose of designing the two cascaded converters.
Results show that conduction losses are dominant in both types of converters in NPT
and PT IGBTs for 11kV and 33kV systems. The equal-sized converter is only likely to
be useful in one case (27-levels in the 33kV system). The ternary-sequence converter
produces lower losses in all other cases, and this is especially noticeable for the 81-level
converter operating in an 11kV network
- …