44,354 research outputs found

    Medical image enhancement using threshold decomposition driven adaptive morphological filter

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    One of the most common degradations in medical images is their poor contrast quality. This suggests the use of contrast enhancement methods as an attempt to modify the intensity distribution of the image. In this paper, a new edge detected morphological filter is proposed to sharpen digital medical images. This is done by detecting the positions of the edges and then applying a class of morphological filtering. Motivated by the success of threshold decomposition, gradientbased operators are used to detect the locations of the edges. A morphological filter is used to sharpen these detected edges. Experimental results demonstrate that the detected edge deblurring filter improved the visibility and perceptibility of various embedded structures in digital medical images. Moreover, the performance of the proposed filter is superior to that of other sharpener-type filters

    Novel CCII-based Field Programmable Analog Array and its Application to a Sixth-Order Butterworth LPF

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    In this paper, a field programmable analog array (FPAA) is proposed. The proposed FPAA consists of seven configurable analog blocks (CABs) arranged in a hexagonal lattice such that the CABs are directly connected to each other. This structure improves the overall frequency response of the chip by decreasing the parasitic capacitances in the signal path. The CABS of the FPAA is based on a novel fully differential digitally programmable current conveyor (DPCCII). The programmability of the DPCCII is achieved using digitally controlled three-bit MOS ladder current division network. No extra biasing circuit is required to generate specific analog control voltage signals. The DPCCII has constant standby power consumption, offset voltage, bandwidth and harmonic distortions over all its programming range. A sixth-order Butterworth tunable LPF suitable for WLAN/WiMAX receivers is realized on the proposed FPAA. The filter power consumption is 5.4mW from 1V supply; it’s cutoff frequency is tuned from 5.2 MHz to 16.9 MHz. All the circuits are realized using 90nm CMOS technology from TSMC. All simulations are carried out using Cadence

    The oscillatory distribution of distances in random tries

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    We investigate \Delta_n, the distance between randomly selected pairs of nodes among n keys in a random trie, which is a kind of digital tree. Analytical techniques, such as the Mellin transform and an excursion between poissonization and depoissonization, capture small fluctuations in the mean and variance of these random distances. The mean increases logarithmically in the number of keys, but curiously enough the variance remains O(1), as n\to\infty. It is demonstrated that the centered random variable \Delta_n^*=\Delta_n-\lfloor2\log_2n\rfloor does not have a limit distribution, but rather oscillates between two distributions.Comment: Published at http://dx.doi.org/10.1214/105051605000000106 in the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Is Helicobacter Pylori Associated with a Migraine?

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    Objective: To determine whether Helicobacter pylori (H. pylori) is associated with migraine headache. Design: Case-control study. Settings: Local tertiary Hospitals in Cairo, Egypt and in HaferAlbaten, Saudi Arabia. Participants: A total of 70 patients with migraine who were 7 to 17 years old and who fulfilled the International Headache Society criteria for migraine and a total of 50 controls without migraine who were matched by the country of origin, age, sex, ethnicity, and socioeconomic status to the 70 migraine cases. Main Outcome Measures: Antibody levels to H. pylori (IgG) and H. pylori stool antigens were compared between the two groups. Results: Significant association was found between H. pylori and migraine and of the total of 70 migraineur cases, 55.7% were positive for H. pylori stool antigen testing compared to 20% in control group (P value=0.0002). Joint pain was reported in 44.3% and 18.0% of cases and controls respectively (P value=0.0034). Conclusion: H. pylori is associated with migraine without aura and may be a causative factor. Moreover, H. pylori may induce joint pain in the migraineur patients

    Real-time speech encoding based on Code-Excited Linear Prediction (CELP)

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    This paper reports on the work proceeding with regard to the development of a real-time voice codec for the terrestrial and satellite mobile radio environments. The codec is based on a complexity reduced version of code-excited linear prediction (CELP). The codebook search complexity was reduced to only 0.5 million floating point operations per second (MFLOPS) while maintaining excellent speech quality. Novel methods to quantize the residual and the long and short term model filters are presented
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