210 research outputs found

    Parallel, Self-Organizing, Hierarchical Neural Networks

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    A new neural network architecture called the parallel self-organizing hierarchical neural network (PSHNN) is discussed. The PSHNN involves a number of stages in which each stage can be a particular neural network (SNN). At the end of each SNN, error detection is carried out, and a number of input vectors are rejected. Between 2 SNN’s there is a nonlinear transformation of those input vectors rejected by the first SNN. The PSHNN has many desirable properties such as optimized system complexity in the sense of minimized self-organizing number of stages, high classification accuracy, minimized learning and recall times, and truly parallel architectures in which all SNN’s are operating simultaneously without waiting for data from each other during testing. The experiments performed in comparison to multilayered networks with backpropagation training indicated the superiority of the PSHN

    Fast Algorithms for the Real Discrete Fourier Transform

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    Fast algorithms for the computation of the real discrete Fourier transform (RDFT) are discussed. Implementations based on the RDFT are always efficient whereas the implementations based on the DFT are efficient only when signals to be processed are complex. The fast real Fourier (FRFT) algorithms discussed are the radix-2 decimation-in-time (DIT), the radix-2 decimation-in-frequency (DIF), the radix-4 DIT, the split-radix DIT, the split-radix DIF, the prime-factor, the Rader prime, and the Winograd FRFT algorithms

    VLSI Implementation of Discrete Cosine Transform Based on the Shared-Multiplier Algorithm

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    In this paper a new algorithm for discrete cosine transform (DCT) is proposed. This algorithm is especially efficient for VLSI implementation because each multiplier in @e 1-D DCT is shared by two constants rather than one. This greatly reduces the chip area, and the high speed characteristics are still retained. Based on this algorithm, we have developed the corresponding bit-parallel, fully-pipelined architecture for the size-8 DCT. The core area of the chip is only 8.6mm x 8.5mm, using 1.2um double-metal single-poly CMOS technology. This chip is simulated for operation at the maximum speed of 100 MHz which far exceeds the speed requirement of the HDTV system (70 MHz)

    Advances in Nonlinear Matched Filtering

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    Symmetric nonlinear matched filters (SNMF’s) involve the transformation of the signal spectrum and the filter transfer function through pointwise nonlinearities before they are multiplied in the transform domain. The resulting system is analogous to a 3-layer neural net The experimental and theoretical results discussed indicate that SNMF’s hold considerable potential to achieve high-power of discrimination, resolution and large SNR. The statistical analysis of a particular SNMF in the 2-class problem indicates that the performance coefficient of the SNMF is about four times larger than the performance coefficient of the classical matched filter. In terms of resolving closeby signals, there seems to be no limit to die achievable resolution. However, intermodulation noise has to be carefully monitored

    Fiber mode excitation using phase-only spatial light modulation: Guideline on free-space path design and lossless optimization

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    Phase-only spatial light modulators allow to reshape a Gaussian beam by imposing a given phase distribution along the beam cross section. This technique is widely used in the context of mode-division multiplexing to produce, after propagation through a free-space path, the field designed to excite a given fiber mode. In case of orbital angular momentum modes, the target field is approximated as circularly polarized and several complex algorithms have been developed to increase the purity of the obtained modes. Besides their complexity, those algorithms often exploit higher-order diffraction and spatial filtering, hence entailing power loss. In the theoretical work described here, the mode purity is increased in a simple and efficient way by improving the mode approximation adopted to obtain circularly polarized modes and by optimizing two free parameters in the setup, as demonstrated through pertinent simulations

    A multidisciplinary approach to address climate-resilience, conservation and comfort in traditional architecture: The PROT3CT example

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    Traditional dwellings despite their environmental credentials, due to age, previous damage, and residents unable to afford even the limited maintenance allowed by restrictive legal framework, may offer poor thermal performance, which is expected to be further exacerbated by changing climate. More than 70% of Turkey’s built heritage stock is composed of traditional dwellings, which makes this stock able to create a major impact nationally on the building-related energy use, carbon emissions and population wellbeing. This research aims to develop an evidence-based multidisciplinary methodology for cost-effective retrofit of the traditional dwellings in Turkey, to improve energy performance, satisfy user expectations of comfort, and protect heritage value

    Turner syndrome and associated problems in turkish children: A multicenter study

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    Objective: Turner syndrome (TS) is a chromosomal disorder caused by complete or partial X chromosome monosomy that manifests various clinical features depending on the karyotype and on the genetic background of affected girls. This study aimed to systematically investigate the key clinical features of TS in relationship to karyotype in a large pediatric Turkish patient population. Methods: Our retrospective study included 842 karyotype-proven TS patients aged 0-18 years who were evaluated in 35 different centers in Turkey in the years 2013-2014. Results: The most common karyotype was 45,X (50.7%), followed by 45,X/46,XX (10.8%), 46,X,i(Xq) (10.1%) and 45,X/46,X,i(Xq) (9.5%). Mean age at diagnosis was 10.2±4.4 years. The most common presenting complaints were short stature and delayed puberty. Among patients diagnosed before age one year, the ratio of karyotype 45,X was significantly higher than that of other karyotype groups. Cardiac defects (bicuspid aortic valve, coarctation of the aorta and aortic stenosi) were the most common congenital anomalies, occurring in 25% of the TS cases. This was followed by urinary system anomalies (horseshoe kidney, double collector duct system and renal rotation) detected in 16.3%. Hashimoto’s thyroiditis was found in 11.1% of patients, gastrointestinal abnormalities in 8.9%, ear nose and throat problems in 22.6%, dermatologic problems in 21.8% and osteoporosis in 15.3%. Learning difficulties and/or psychosocial problems were encountered in 39.1%. Insulin resistance and impaired fasting glucose were detected in 3.4% and 2.2%, respectively. Dyslipidemia prevalence was 11.4%. Conclusion: This comprehensive study systematically evaluated the largest group of karyotype-proven TS girls to date. The karyotype distribution, congenital anomaly and comorbidity profile closely parallel that from other countries and support the need for close medical surveillance of these complex patients throughout their lifespan. © Journal of Clinical Research in Pediatric Endocrinology

    A multi-sensor network for the protection of cultural heritage

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    The paper presents a novel automatic early warning system to remotely monitor areas of archaeological and cultural interest from the risk of fire. Since these areas have been treasured and tended for very long periods of time, they are usually surrounded by old and valuable vegetation or situated close to forest regions, which exposes them to an increased risk of fire. The proposed system takes advantage of recent advances in multi-sensor surveillance technologies, using optical and infrared cameras, wireless sensor networks capable of monitoring different modalities (e.g. temperature and humidity) as well as local weather stations on the deployment site. The signals collected from these sensors are transmitted to a monitoring centre, which employs intelligent computer vision and pattern recognition algorithms as well as data fusion techniques to automatically analyze sensor information. The system is capable of generating automatic warning signals for local authorities whenever a dangerous situation arises, as well as estimating the propagation of the fire based on the fuel model of the area and other important parameters such as wind speed, slope, and aspect of the ground surface. © 2011 EURASIP
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