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Driving in the wrong lane: towards a longer life-span of cars
Within the context of product longevity, one especially impactful and ubiquitous product demands further research: the car. Car longevity has been addressed in the context of product life extension and product lifetime optimisation but there have been a few studies on car longevity in the context of business and none specifically from an industrial design context. This paper presents initial findings from preliminary interviews with key industry representatives such as car designers and engineers. It discusses the barriers to and opportunities for designing a car with a longer life-span. This and further data will later be analysed in order to produce a design framework to inform car
designers on life-span and usage optimization through design. Strategies such as increased longevity or use-intensity can potentially reduce the throughput - and thereafter the consumption - of cars. Such a shift in the automotive sector would support the transition from a linear economy to a more sustainable one. The initial findings, however, suggest that a longer life car is not an uncompromised solution and important concessions would have to be made in order to make this an acceptable
product
A novel steganography approach for audio files
We present a novel robust and secure steganography technique to hide images into audio files aiming at increasing the carrier medium capacity. The audio files are in the standard WAV format, which is based on the LSB algorithm while images are compressed by the GMPR technique which is based on the Discrete Cosine Transform (DCT) and high frequency minimization encoding algorithm. The method involves compression-encryption of an image file by the GMPR technique followed by hiding it into audio data by appropriate bit substitution. The maximum number of bits without significant effect on audio signal for LSB audio steganography is 6 LSBs. The encrypted image bits are hidden into variable and multiple LSB layers in the proposed method. Experimental results from observed listening tests show that there is no significant difference between the stego audio reconstructed from the novel technique and the original signal. A performance evaluation has been carried out according to quality measurement criteria of Signal-to-Noise Ratio (SNR) and Peak Signal-to-Noise Ratio (PSNR)
Optimal control of a dengue epidemic model with vaccination
We present a SIR+ASI epidemic model to describe the interaction between human
and dengue fever mosquito populations. A control strategy in the form of
vaccination, to decrease the number of infected individuals, is used. An
optimal control approach is applied in order to find the best way to fight the
disease.Comment: This is a preprint of a paper accepted for presentation at ICNAAM
2011, Halkidiki, Greece, 19-25 September 2011, and to appear in AIP
Conference Proceedings, volume 138
Modeling and Optimal Control Applied to a Vector Borne Disease
A model with six mutually-exclusive compartments related to Dengue disease is
presented. In this model there are three vector control tools: insecticides
(larvicide and adulticide) and mechanical control. The problem is studied using
an Optimal Control (OC) approach. The human data for the model is based on the
Cape Verde Dengue outbreak. Some control measures are simulated and their
consequences analyzed
Insecticide control in a Dengue epidemics model
A model for the transmission of dengue disease is presented. It consists of
eight mutually-exclusive compartments representing the human and vector
dynamics. It also includes a control parameter (insecticide) in order to fight
the mosquitoes. The main goal of this work is to investigate the best way to
apply the control in order to effectively reduce the number of infected humans
and mosquitoes. A case study, using data of the outbreak that occurred in 2009
in Cape Verde, is presented.Comment: Accepted 28/07/2010 in the special session "Numerical Optimization"
of the 8th International Conference of Numerical Analysis and Applied
Mathematics (ICNAAM 2010), Rhodes, Greece, 19-25 September 201
Dynamics of Dengue epidemics using optimal control
We present an application of optimal control theory to Dengue epidemics. This
epidemiologic disease is an important theme in tropical countries due to the
growing number of infected individuals. The dynamic model is described by a set
of nonlinear ordinary differential equations, that depend on the dynamic of the
Dengue mosquito, the number of infected individuals, and the people's
motivation to combat the mosquito. The cost functional depends not only on the
costs of medical treatment of the infected people but also on the costs related
to educational and sanitary campaigns. Two approaches to solve the problem are
considered: one using optimal control theory, another one by discretizing first
the problem and then solving it with nonlinear programming. The results
obtained with OC-ODE and IPOPT solvers are given and discussed. We observe that
with current computational tools it is easy to obtain, in an efficient way,
better solutions to Dengue problems, leading to a decrease of infected
mosquitoes and individuals in less time and with lower costs.Comment: Submitted to Mathematical and Computer Modelling 25/Oct/2009;
accepted for publication, after revision, 22/June/201
Optimization of Dengue Epidemics: a test case with different discretization schemes
The incidence of Dengue epidemiologic disease has grown in recent decades. In
this paper an application of optimal control in Dengue epidemics is presented.
The mathematical model includes the dynamic of Dengue mosquito, the affected
persons, the people's motivation to combat the mosquito and the inherent social
cost of the disease, such as cost with ill individuals, educations and sanitary
campaigns. The dynamic model presents a set of nonlinear ordinary differential
equations. The problem was discretized through Euler and Runge Kutta schemes,
and solved using nonlinear optimization packages. The computational results as
well as the main conclusions are shown.Comment: Presented at the invited session "Numerical Optimization" of the 7th
International Conference of Numerical Analysis and Applied Mathematics
(ICNAAM 2009), Rethymno, Crete, Greece, 18-22 September 2009; RepositoriUM,
id: http://hdl.handle.net/1822/1083
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