University of Twente Publications
University of Twente Repository provides publications of UT scientific staff, in many cases full text and publicly available.
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A generalized FFT algorithm on transputers - Roebbers, Herman; Welch, Peter; Wijbrans, Klaas
A generalized algorithm has been derived for the execution of the Cooley-Tukey FFT algorithm on a distributed memory machine. This algorithm is based on an approach that combines a large number of butterfly operations into one large process per processor. The performance can be predicted from theory. The actual algorithm has been implemented on a transputer array, and the performance of the implementation has been measured for various sizes of the complex input vector. It is shown that the algorithm scales linearly with the number of transputers and the problem size.
Facial recognition using new LBP representations - Akoushideh, Alireza; Veldhuis, R.N.J.; Spreeuwers, L.J.; Maybodi, Babak M.-N.
In this paper, we propose a facial recognition based on the LBP operator. We divide the face into non-overlapped regions. After that, we classify a training set using each region at a time under different configurations of the LBP operator. Regarding to the best recognition rate, we consider a weight and specific LBP configuration to the regions. To represent the face image, we extract LBP histograms with the specific configuration (radius and neighbors) and concatenate them into feature histogram. We propose a multi-resolution approach, to gather local and global information and improve the recognition rate. To evaluate our proposed approach,...
Semiparametric score sevel susion: Gaussian sopula approach - Susyanyo, N.; Klaassen, C.A.J.; Veldhuis, R.N.J.; Spreeuwers, L.J.
Score level fusion is an appealing method for combining multi-algorithms, multi- representations, and multi-modality biometrics due to its simplicity. Often, scores are assumed to be independent, but even for dependent scores, accord- ing to the Neyman-Pearson lemma, the likelihood ratio is the optimal score level fusion if the underlying distributions are known. However, in reality, the dis- tributions have to be estimated. The common approaches are using parametric and nonparametric models. The disadvantage of the parametric method is that sometimes it is very dicult to choose the appropriate underlying distribution, while the nonparametric method is computationally expensive when the dimen-...
Method for transforming a feature vector - Veldhuis, Raymond N.J.; Chen, Chun; Kevenaar, Thomas A.M.; Akkermans, Antonius H.M.
The present invention relates to a method for transforming a feature vector comprising a first and a second feature represented by a first and a second feature value, respectively, into a feature code using an encoder, said feature code usable in an algorithm and having a predetermined number of bits, said method comprising the steps of determining for each of the first and the second features the performance as a function of the length of the feature code, and using the dependency between the performance and the feature code length for each of the individual features derived in the step...
Real-time multiprocessor architecture for sharing stream processing accelerators - Dekens, B.H.J.; Bekooij, M.J.G.; Smit, G.J.M.
Stream processing accelerators are often applied in MPSoCs for software defined radios. Sharing of these accelerators between different streams could improve their utilization and reduce thereby the hardware cost but is challenging under real-time constraints.
In this paper we introduce entry- and exit-gateways that are responsible for multiplexing blocks of data over accelerators under real-time constraints. These gateways check for the availability of sufficient data and space and thereby enable the derivation of a dataflow model of the application. The dataflow model is used to verify the worst-case temporal behavior based on the sizes of the blocks of data used...
Coriolis flow sensor - Lotters, Joost Conrad; Katerberg, Marcel Ronald; Hakvoort, Wouter Bernardus Johannes; Kruijswijk, Willem David; Ridder, Lubbert van de
A Domain Specific Language for Performance Evaluation of Medical Imaging Systems - Berg, Freek van den; Remke, Anne; Haverkort, Boudewijn R.
We propose iDSL, a domain specific language and toolbox for performance evaluation of Medical Imaging Systems. iDSL provides transformations to MoDeST models, which are in turn converted into UPPAAL and discrete-event MODES models. This enables automated performance evaluation by means of model checking and simulations. iDSL presents its results visually. We have tested iDSL on two example image processing systems. iDSL has successfully returned differentiated delays, resource utilizations and delay bounds. Hence, iDSL helps in evaluating and choosing between design alternatives, such as the effects of merging subsystems onto one platform or moving functionality from one platform to another.
Elasto-capillary folding using stop-programmable hinges fabricated by 3D micro-nachining - Legrain, Antoine; Berenschot, Erwin J.W.; Tas, Niels R.; Abelmann, Leon
We show elasto-capillary folding of silicon nitride objects with accurate folding angles be- tween flaps of (70.6 ± 0.1)° and demonstrate the feasibility of such accurate micro-assembly with a final folding angle of 90°. The folding angle is defined by stop-programmable hinges that are fabricated starting from silicon molds employing accurate three-dimensional corner lithography. This nano-patterning method exploits the conformal deposition and the subse- quent timed isotropic etching of a thin film in a 3D shaped silicon template. The technique leaves a residue of the thin film in sharp concave corners which can be used as an inversion mask in...
Toward a theory of complexity escalation and collapse for system of systems - Bradley, Joseph; Efatmaneshnik, Mahmoud; Rajabalinejad, Mohammad
In this paper we urge the creation of new managerial tools and techniques that are relevant to the complexity of today’s system of systems (SOS). Normal modes of command and control systems cannot be effective under conditions where new constraints are added on a recurrent basis to the system of systems in response to emergent problems within the systems due to increased coupling introduced in component elements of the SOS. We present a first-step understanding of why unanticipated failures find more potential and more pathways to their occurrence when interventions in SOS operations, standards or processes are conducted without enough...
A model based safety architecture framework for Dutch high speed train lines - Schuitemaker, K.; Braakhuis, J.G.; Rajabalinejad, M.
This paper presents a model-based safety architecture framework (MBSAF) for capturing and sharing architectural knowledge of safety cases of safetycritical systems of systems (SoS). Whilst architecture frameworks in the systems engineering domain consider safety often as dependent attribute, this study focusses specifically on sharing architectural knowledge of safety cases between stakeholders and managing safety in systems development. For this purpose, we adapt the A3 architecture overview (A3AO) tool. The application is shown though the case study of Dutch high speed train lines and shows how to derive requirements from various stakeholders by carrying out iterative validations of the A3AOs. The...
Relation between speckle decorrelation and optical phase conjugation (OPC)- based turbidity suppression through dynamic scattering media: a study on in vivo mouse skin - Jang, Mooseok; Ruan, Haowen; Vellekoop, Ivo M.; Judkewitz, Benjamin; Chung, Euiheon; Yang, Changhuei
Light scattering in biological tissue significantly limits the accessible depth for localized optical interrogation and deep-tissue optical imaging. This challenge can be overcome by exploiting the time-reversal property of optical phase conjugation (OPC) to reverse multiple scattering events or suppress turbidity. However, in living tissue, scatterers are highly movable and the movement can disrupt time-reversal symmetry when there is a latency in the OPC playback. In this paper, we show that the motion-induced degradation of the OPC turbidity-suppression effect through a dynamic scattering medium shares the same decorrelation time constant as that determined from speckle intensity autocorrelation – a popular...
Cognitive ability and self-control in relation to dietary habits, physical activity and bodyweight in adolescents - Junger, Marianne; Kampen, Margit van
Previous studies showed that cognitive ability is related to health and mortality. The cause of this relationship remains largely unknown. One plausible explanation is that cognitive ability is related to behaviours that affect health. This study investigates whether cognitive ability is related to healthy dietary habits, physical activity and appropriate bodyweight in adolescents and examines whether self-control mediates the relationship between cognitive ability and health behaviour.
In total 201 high-school students aged between 15 and 20 participated in the study. They completed three cognitive tests, measuring cognitive ability, reaction time and memory span, and completed a questionnaire on self-control, dietary habits,...
Opportunities, Constraints and Perceptions of Rural Communities Regarding Their Potential to Contribute to Forest Landscape Transitions Under REDD+: Case Studies from Mexico - Skutsch, M.; Borrego, A.; Morales-Barquero, L.; Paneque-Gálvez, J.; Salinas Melgoza, M.A.; Ramirez, M.I.; Perez-Salicrup, D.; Benet, D.; Monroy, S.; Gao, Y.
In Mexico, REDD+ is being presented as a win-win policy enabling forest communities to benefit financially and diversify their income sources while preserving and increasing their forest carbon stocks through more sustainable management. Under the national programme, it is expected that forest communities will have opportunities to tailor their own approaches. However, to date there is little understanding about what opportunities and constraints exist in reality for forest communities to contribute to REDD+, and even less about how their members perceive these opportunities. We assess potential and constraints at community level and investigate perceptions about opportunities in REDD+ and strategies...
Force limited vibration testing: an evaluation of the computation of C2 for real load and probabilistic source - Wijker, J.J.; Boer, A. de; Ellenbroek, M.H.M.
To prevent over-testing of the test-item during random vibration testing Scharton proposed and discussed the force limited random vibration testing (FLVT) in a number of publications. Besides the random vibration specification, the total mass and the turn-over frequency of the load (test item), is a very important parameter for FLVT. A number of computational methods to estimate are described in the literature, i.e., the simple and the complex two degrees of freedom system, STDFS and CTDFS, respectively. The motivation of this work is to evaluate the method for the computation of a realistic value of to perform a representative random...