Medical image reconstruction,processing, visualization,and analysis: the MIPG perspective. Medical Image Processing Group

In this paper, we identify and describe the key ideas, concepts and software related to Medical Imaging that emerged from our research group, which is commonly known by the acronym MIPG, denoting Medical Image Processing Group. For the purpose of our presentation, we consider the entire discipline of Medical Imaging to consist of the areas of acquisition, postprocessing, evaluation, and application. We are indeed fortunate to be able to discuss seminal research from our group in each of these areas. In Section II, we identify relevant moments of inception and describe our past contributions. Our achievements, current activities, and future directions are summarized in Section III, Section IV, and Section V, respectively; the keys to our success are listed in Section V     

Cognitive-Behavioral Analysis System of Psychotherapy as a Maintenance Treatment for Chronic Depression.

Although the efficacy of maintenance pharmacotherapy for the prevention of recurrence in major depressive disorder (MDD) is well documented, few studies have tested the efficacy of psychotherapy as a maintenance treatment. The authors examined the efficacy of the cognitive-behavioral analysis system of psychotherapy (CBASP) as a maintenance treatment for chronic forms of MDD. Eighty-two patients who had responded to acute and continuation phase CBASP were randomized to monthly CBASP or assessment only for 1 year. Significantly fewer patients in the CBASP than assessment only condition experienced a recurrence. The 2 conditions also differed significantly on change in depressive symptoms over time. These findings support the use of CBASP as a maintenance treatment for chronic forms of MDD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A wide-band high-accuracy incremental ADC

In this paper, a high resolution and wideband incremental ADC with extended counting is described and analyzed. The modulator introduced inter-stage gain to reduce the quantization noise without adding any hardware. Also, a gain scaling technique was used to decrease the power consumption by reducing the integrators’ output swing. First, the 2nd order incremental ΔΣ ADC and 11-bit SAR ADC were measured separately. Second, the incremental ΔΣ ADC with extended counting was tested. It achieved a 91.6 dB dynamic range and 77.8 dB SNDR in the 0–1.25 MHz signal band. The total power consumption is 53.5 mW with dual power supplies (analog 3.3 V, digital 1.8 V).     

Enhanced split-architecture delta–sigma ADCs

A split delta–sigma ADC topology is proposed, which provides enhanced noise shaping by cross-coupling the quantization errors of the two halves of the structure. Unlike the multi-stage noise shaping (MASH) architecture, the new structure is insensitive to mismatch errors, and it does not reduce the stability of the loops. Simulations confirm the effectiveness of the proposed scheme.     

Mode selection schemes for unicasting device‐to‐device communications supported by network coding

Device‐to‐device (D2D) communication in a cellular spectrum increases the spectral and energy efficiency of local communication sessions, while also taking advantage of accessing licensed spectrum and higher transmit power levels than when using unlicensed bands. To realize the potential benefits of D2D communications, appropriate mode selection algorithms that select between the cellular and D2D communication modes must be designed. On the other hand, physical‐layer network coding (NWC) at a cellular base station—which can be used without D2D capability—can also improve the spectral efficiency of a cellular network that carries local traffic. In this paper, we ask whether cellular networks should support D2D communications, physical‐layer NWC, or both. To this end, we study the performance of mode selection algorithms that can be used in cellular networks that use physical‐layer NWC and support D2D communications. We find that the joint application of D2D communication and NWC scheme yields additional gains compared with a network that implements only one of these schemes, provided that the network implements proper mode selection and resource allocation algorithms. We propose 2 mode selection schemes that aim to achieve high signal‐to‐interference‐plus‐noise ratio and spectral efficiency, respectively, and take into account the NWC and D2D capabilities of the network.     

A 100-dB gain-corrected delta-sigma audio DAC with headphone driver

An oversampled digital-to-analog converter (DAC) with a 100-dB A-weighted dynamic range is presented. It uses a switched-capacitor (SC) array to transfer the sampled charges directly into the headphone driver. The overall DAC gain is precisely controlled by a novel reference stage. A new dynamic element matching algorithm, based on split-set data-weighted averaging (SDWA), is used to improve the dynamic range and to reduce the nonlinearity caused by mismatches in the multibit DAC.     

Switched-capacitor track-and-hold amplifier with low sensitivity to op-amp imperfections

This paper describes a high-precision switched-capacitor (SC) track-and-hold amplifier (THA) stage. It uses a novel continuous-time correlated double sampling (CDS) scheme to desensitize the operation to amplifier imperfections. Unlike earlier predictive-CDS THAs, the circuit does not need a sample-and-held input signal for its operation. During the tracking period, an auxiliary continuous-time signal path is established, which predicts the output voltage during the holding period. This allows accurate operation even for low amplifier gains and large offsets over a wide input frequency range. Extensive simulations were performed to compare the performance of the proposed THA with earlier circuits utilizing CDS. The results verify that its operation is far more robust than that of any previously described THA.     

Electromyographic investigation of abdominal exercises and the effects of fatigue

Abdominal exercises are widely used to develop the anterior muscles of the trunk. These exercises can be undertaken without the aid of equipment, but increasingly manufacturers are developing equipment which purportedly enhances the training effect for abdominal muscles. As there are many different products and exercises used for abdominal muscle development, it is likely that some are more effective than others. This study aimed to investigate the effectiveness of five commonly performed abdominal exercises. A second aim was to investigate the effects of fatigue on these exercises. Five different types of abdominal exercise [standard crunch (sit-up) with bent knees, gym ball crunch, crunch with 5 kg weight held behind the head, legs raised crunch and a commercially manufactured roller crunch] were examined using integrated surface electromyography (IEMG). The lower rectus abdominis (LRA), upper rectus abdominis (URA) and obliquus externus abdominis (EO) of 15 healthy male participants [age (mean +/- SD) 22.2 +/- 6.8 years; height 1.77 +/- 0.06 m; mass 79.3 +/- 10.7 kg] were monitored using a four-channel special purpose EMG data logger. Three trials of each exercise were performed in random order and normalized to enable comparisons between muscles and exercises. At a later date, ten participants were then re-tested when fresh and after a 30 min whole-body fatigue protocol that specifically targeted the abdominal muscles. Two exercises were evaluated, the abdominal roller crunch and legs raised crunch, which were judged to be the least and most effective, respectively, of the five exercises previously used. The normalized IEMG showed significant (p < 0.001) differences between exercises (gym ball crunch = 86.0 +/- 7.5%; legs raised crunch = 79.9 +/- 5.1%; 5 kg weight crunch = 65.1 +/- 13.4%; standard crunch = 56.2 +/- 3.2%; and roller crunch = 45.0 +/- 11.4%). Post-fatigue, the normalized mean IEMG for both exercises increased significantly (p < 0.05) for LRA and URA muscles but not for the EO (p > 0.05). It was concluded that exercises can be constructed to provide a greater challenge to abdominal muscles, commercially available roller-type equipment appears to be little different from the standard abdominal crunch with bent knees, and fatiguing exercise results in the LRA and URA being more highly activated. These findings provide more detailed knowledge and understanding of the effects of different forms of abdominal exercise.