1,934 research outputs found

Recommended from our members

### A Taxonomy and Process for Structured Innovation, Creative Problem Solving and Opportunity Creating

Myriad problem-solving techniques exist, but the literature indicates that people and organisations lack appreciation of the range and nature of the techniques available, and do not fully understand the use, value and potential of such techniques. A more profound understanding of the role that different types of problem-solving technique can play and how they can be deployed more effectively in creativity and innovation processes would form a sound basis for the improvement of creative practices and innovation processes within organisations.
This research aims to provide the means to improve innovation and creative problem solving by using more effective matching of participants’ cognitive styles to the techniques available.
In order to achieve synergy in the relationship between the techniques and their users, this research examined the contribution that techniques make to the creative problem solving cycle, and the degree of creativity they encourage was explored first through a review of the relevant literature. This resulted in a novel classification of the techniques and the cognitive skills involved in creative problem solving.
The relationship between people and techniques was investigated through a set of experiments in which individuals and groups undertook problem-solving exercises and responded to a questionnaire to evaluate their experience of the exercise. Participants’ preferred cognitive styles were determined so that problem-solving techniques could be selectively assigned to align with or be opposed to their preferred cognitive styles. Results were analysed using both qualitative and quantitative approaches.
The cognitive styles provided parameters for a taxonomic framework for the techniques. An improved approach to describing personalities based on a continuum of cognitive abilities instead of a set of discrete cognitive styles was a further outcome of this work. The results demonstrate that people show significant preference for problem-solving activities and techniques that are in accord with their preferred cognitive styles. A key conclusion is that people who follow such an approach will improve their ideation productivity in terms of quantity and novelty and will gain more satisfaction from their experience than those who do not. Analysis of the purpose of creative problem solving techniques and the cognitive styles that such techniques encourage, revealed synergy between paradigms used by psychologists and those used by technologists. The synergy between paradigms established a platform for a new creative problem-solving strategy

### Operator-Valued Frames for the Heisenberg Group

A classical result of Duffin and Schaeffer gives conditions under which a
discrete collection of characters on $\mathbb{R}$, restricted to $E = (-1/2,
1/2)$, forms a Hilbert-space frame for $L^2(E)$. For the case of characters
with period one, this is just the Poisson Summation Formula. Duffin and
Schaeffer show that perturbations preserve the frame condition in this case.
This paper gives analogous results for the real Heisenberg group $H_n$, where
frames are replaced by operator-valued frames. The Selberg Trace Formula is
used to show that perturbations of the orthogonal case continue to behave as
operator-valued frames. This technique enables the construction of
decompositions of elements of $L^2(E)$ for suitable subsets $E$ of $H_n$ in
terms of representations of $H_n$

### Coordinating Complementary Waveforms for Sidelobe Suppression

We present a general method for constructing radar transmit pulse trains and
receive filters for which the radar point-spread function in delay and Doppler,
given by the cross-ambiguity function of the transmit pulse train and the pulse
train used in the receive filter, is essentially free of range sidelobes inside
a Doppler interval around the zero-Doppler axis. The transmit pulse train is
constructed by coordinating the transmission of a pair of Golay complementary
waveforms across time according to zeros and ones in a binary sequence P. The
pulse train used to filter the received signal is constructed in a similar way,
in terms of sequencing the Golay waveforms, but each waveform in the pulse
train is weighted by an element from another sequence Q. We show that a
spectrum jointly determined by P and Q sequences controls the size of the range
sidelobes of the cross-ambiguity function and by properly choosing P and Q we
can clear out the range sidelobes inside a Doppler interval around the zero-
Doppler axis. The joint design of P and Q enables a tradeoff between the order
of the spectral null for range sidelobe suppression and the signal-to-noise
ratio at the receiver output. We establish this trade-off and derive a
necessary and sufficient condition for the construction of P and Q sequences
that produce a null of a desired order

### Submodularity and Optimality of Fusion Rules in Balanced Binary Relay Trees

We study the distributed detection problem in a balanced binary relay tree,
where the leaves of the tree are sensors generating binary messages. The root
of the tree is a fusion center that makes the overall decision. Every other
node in the tree is a fusion node that fuses two binary messages from its child
nodes into a new binary message and sends it to the parent node at the next
level. We assume that the fusion nodes at the same level use the same fusion
rule. We call a string of fusion rules used at different levels a fusion
strategy. We consider the problem of finding a fusion strategy that maximizes
the reduction in the total error probability between the sensors and the fusion
center. We formulate this problem as a deterministic dynamic program and
express the solution in terms of Bellman's equations. We introduce the notion
of stringsubmodularity and show that the reduction in the total error
probability is a stringsubmodular function. Consequentially, we show that the
greedy strategy, which only maximizes the level-wise reduction in the total
error probability, is within a factor of the optimal strategy in terms of
reduction in the total error probability

### Detection Performance in Balanced Binary Relay Trees with Node and Link Failures

We study the distributed detection problem in the context of a balanced
binary relay tree, where the leaves of the tree correspond to $N$ identical and
independent sensors generating binary messages. The root of the tree is a
fusion center making an overall decision. Every other node is a relay node that
aggregates the messages received from its child nodes into a new message and
sends it up toward the fusion center. We derive upper and lower bounds for the
total error probability $P_N$ as explicit functions of $N$ in the case where
nodes and links fail with certain probabilities. These characterize the
asymptotic decay rate of the total error probability as $N$ goes to infinity.
Naturally, this decay rate is not larger than that in the non-failure case,
which is $\sqrt N$. However, we derive an explicit necessary and sufficient
condition on the decay rate of the local failure probabilities $p_k$
(combination of node and link failure probabilities at each level) such that
the decay rate of the total error probability in the failure case is the same
as that of the non-failure case. More precisely, we show that $\log
P_N^{-1}=\Theta(\sqrt N)$ if and only if $\log p_k^{-1}=\Omega(2^{k/2})$

### On the use of artificial neural networks for the analysis of survival data

Artificial neural networks are a powerful tool for analyzing data sets where there are complicated nonlinear interactions between the measured inputs and the quantity to be predicted. We show that the results obtained when neural networks are applied to survival data depend critically on the treatment of censoring in the data. When the censoring is modeled correctly, neural networks are a robust model independent technique for the analysis of very large sets of survival data

### Waveform libraries: Measures of effectiveness for radar scheduling

Our goal was to provide an overview of a circle of emerging ideas in the area of waveform scheduling for active radar. Principled scheduling of waveforms in radar and other active sensing modalities is motivated by the nonexistence of any single waveform that is ideal for all situations encountered in typical operational scenarios. This raises the possibility of achieving operationally significant performance gains through closed-loop waveform scheduling. In principle, the waveform transmitted in each epoch should be optimized with respect to a metric of desired performance using all information available from prior measurements in conjunction with models of scenario dynamics. In practice, the operational tempo of the system may preclude such on-the-fly waveform design, though further research into fast adaption of waveforms could possibly attenuate such obstacles in the future. The focus in this article has been on the use of predesigned libraries of waveforms from which the scheduler can select in lieu of undertaking a real-time design. Despite promising results, such as the performance gains shown in the tracking example presented here, many challenges remain to be addressed to bring the power of waveform scheduling to the level of maturity needed to manifest major impact as a standard component of civilian and military radar systems.Douglas Cochran, Sofia Suvorova, Stephen D. Howard and Bill Mora

- …