Denis Onen

A Row-Parallel 8

An algebraic integer (AI)-based time-multiplexed row-parallel architecture and two final reconstruction step (FRS) algorithms are proposed for the implementation of bivariate AI encoded 2-D discrete cosine transform (DCT). The architecture directly realizes an error-free 2-D DCT without using FRSs between row-column transforms, leading to an 8 × 8 2-D DCT that is entirely free of quantization errors in AI basis. As a result, the user-selectable accuracy for each of the coefficients in the FRS facilitates each of the 64 coefficients to have its precision set independently of others, avoiding the leakage of quantization noise between channels as is the case for published DCT designs. The proposed FRS uses two approaches based on: 1) optimized Dempster-Macleod multipliers, and 2) expansion factor scaling. This architecture enables low-noise high-dynamic range applications in digital video processing that requires full control of the finite-precision computation of the 2-D DCT. The proposed architectures and FRS techniques are experimentally verified and validated using hardware implementations that are physically realized and verified on field-programmable gate array (FPGA) chip. Six designs, for 4-bit and 8-bit input word sizes, using the two proposed FRS schemes, have been designed, simulated, physically implemented, and measured. The maximum clock rate and block rate achieved among 8-bit input designs are 307.787 MHz and 38.47 MHz, respectively, implying a pixel rate of 8 × 307.787≈2.462 GHz if eventually embedded in a real- time video-processing system. The equivalent frame rate is about 1187.35Hz for the image size of 1920 × 1080. All implementations are functional on a Xilinx Virtex-6 XC6VLX240T FPGA device.

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A time-multiplexed row-parallel architecture is proposed for the real-time implementation of bivariate algebraic integer (AI) encoded 2-D discrete cosine transform (DCT) of images and video sequences. The architecture is based on the Arai algorithm with AI encoding. This leads to an 8×8 2-D DCT which is entirely free of quantization errors. The error free coefficients may be converted into a regular arithmetic format using a final reconstruction step (FRS) at the output stage. The accuracy of the FRS allows each of the 64 coefficients to have its precision set independent of other coefficients without the leakage of quantization noise between coefficient channels. Our architecture leads to low-noise applications in digital video compression, coding, and other image processing applications that rely on the fast systolic computation of the 2-D DCT. A prototype of the 2-D DCT is physically realized, tested, and verified on chip, using a Xilinx Virtex-4 Sx35-10ff668 device. The maximum clock rate was Fclock = 121 MHz, implying an equivalent frame sample rate of 466 Hz, for an image frame size of 1920×1080, which is a common high definition video format.

8 2-D DCT Architecture Using Algebraic Integer-Based Exact Computation

Background: Gastric Electrical Stimulation (GES) has been suggested as a new tool for the treatment of obesity. Among the known methods for GES, only Neural Gastric Electrical Stimulation (NGES) provides direct control of contractility without utilizing the spontaneously existing gastric electrical activity as an intermediary. However, only one of the established GES techniques, gastric pacing, has been described to produce retrograde peristalsis for delaying gastric emptying. The aim of this study was to explore the possibility of producing retrograde peristalsis using either single electrode set or dual electrode set NGES. Methods: 8 anesthetized dogs underwent laparotomy and implantation of 2 circumferential electrode sets approximately 3 cm and 7 cm proximal to the pylorus, respectively. Single-set and dual-set NGES sessions were repeatedly administered using a custom-designed implantable neurostimulator. Gastric motility patterns were captured using 3 force transducers implanted on the anterior gastric wall along the gastric axis. Motility indices and velocities were employed to quantify the produced contractile patterns. Results: Both single-set and dual-set NGES produced circumferential lumen-occluding contractions in the vicinity of the electrode sets. The invoked contractions propagated proximally in a retrograde fashion. The propagation scope was different depending on the number of electrode sets used. Different velocities of the invoked retrograde contractions associated with single- and dual-set NGES were observed and quantified. Contractility patterns reflected by the normalized motility indices were very similar regardless of the electrode stimulation technique. Conclusion: Pre-pyloric NGES can produce controlled retrograde peristalsis and serve as another avenue for the treatment of obesity.

Algebraic integer based 8×8 2-D DCT architecture for digital video processing

Transformation and quantization play a critical role in video codecs. Recently proposed algebraic-integer-(AI-) based discrete cosine transform (DCT) algorithms are analyzed in the presence of quantization, using the High Efficiency Video Coding (HEVC) standard. AI DCT is implemented and tested on asynchronous quasi delay-insensitive logic, using Achronix SPD60 field programmable gate array (FPGA), which leads to lower complexity, higher speed of operation, and insensitivity to process-voltagetemperature variations. Performance of AI DCT with HEVC is measured in terms of the accuracy of the transform coefficients and the overall rate-distortion (R-D) characteristics, using HM 7.1 reference software. Results indicate a 31% improvement over the integer DCT in the number of transformcoefficients having error within 1%. The performance of the 65 nmasynchronous hardware in terms of speed of operation is investigated and compared with the 65 nm synchronous Xilinx FPGA. Considering word lengths of 5 and 6 bits, a speed increase of 230% and 199% is observed, respectively. These results indicate that AI DCT can be potentially utilized in HEVC for applications demanding high accuracy as well as high throughput. However, novel quantization schemes are required to allow the accuracy improvements obtained.

Pre-Pyloric Neural Electrical Stimulation Produces Cholinergically-Mediated Reverse Peristalsis in the Acute Canine Model of Microprocessor-Invoked Gastric Motility for the Treatment of Obesity

Manipulation of gastric motility by gastric electrical stimulation (GES) has been suggested as a minimally invasive alternative treatment of gastric motility disorders and obesity. However, only neural GES (NGES) has been successful in invoking gastric contractions. Nevertheless, the relationship between these contractions and the controlling NGES parameters has not been quantified. We aimed at determining the relationship between the electrical energy delivered to the tissue as a function of NGES parameters, and the strength and duration of the resulting invoked gastric contractions. Five healthy mongrel dogs underwent subserosal prepyloric implantation of two NGES electrode pairs. Gastric motility was captured by a force transducer implanted in the vicinity of the distal pair of stimulating electrodes. Custom-designed implantable stimulator delivered NGES with 8-16 V (peak-to-peak) amplitudes, and 60-100% duty cycles. Normalized motility index (MI) was utilized to quantify the contractions recorded from the force transducer. The MI increased with increasing voltage amplitudes. However, it remained remarkably constant across all duty cycles when voltage was held constant. Calculated motility generation efficiency indices (MGEI) indicated that highest energy efficiency for invoked motility was achieved at the lowest duty cycle. The parametric data obtained in the present study can be utilized to optimize the power efficiency of implantable gastric neurostimulators

Asynchronous realization of algebraic integer-based 2D DCT using achronix speedster SPD60 FPGA

Purpose This paper aims to offer an integrative conceptual theory of conflict and reports on the nomological net of team conflict profiles. Specifically, it integrates social self-preservation theory with information-processing theory to better understand the occurrence of team profiles involving task conflict, relationship conflict and process conflict. Design/methodology/approach The study collected data from 178 teams performing and engineering design tasks. The multilevel nomological net that was examined consisted of constructive controversy, psychological safety and team-task performance (team level), as well as perceptions of learning, burnout and peer ratings of performance (individual level). Findings Findings indicated mixed support for the associations between conflict profiles and the hypothesized nomological net. Research limitations/implications Future research should consider teams’ profiles of team conflict types rather than examining task, relationship and process conflict in isolation. Practical implications Teams can be classified into profiles of team conflict types with implications for team functioning and effectiveness. As a result, assessment and team launch should consider team conflict profiles. Originality/value The complexity perspective advanced here will allow research on conflict types to move forward beyond the extensive research examining conflict types in isolation rather than their interplay.

Parametric Study of Neural Gastric Electrical Stimulation in Acute Canine Models

Teamwork is frequently used to tackle complex and demanding tasks in organizational and educational settings. While teamwork may offer substantial benefits, the challenges of working effectively in teams are considerable. This study examines the roles of psychological contract breach and person-team fit in relation to teams’ effectiveness. Twelve teams of electrical and computer engineering students were surveyed at three time points to assess their perceptions of personteam fit and psychological contract breach. Results of a longitudinal mediation model supported our hypotheses that team level psychological contract breach would result in decreased supplementary fit and increased complementary fit. Regarding team outcomes, we found that perceptions of supplementary fit increased team member peer feedback ratings, while perceptions of complementary fit increased team potency. Follow-up analyses revealed that psychological safety was positively related to psychological contract breach. Implications for practice are discussed.

The multilevel nomological net of team conflict profiles

With the knowledge that team work is not always associated with high(er) performance, we draw from the Multi-Level Theory of Psychological Contracts, Person-Environment Fit Theory, and Optimal Distinctiveness Theory to study shared perceptions of psychological contract (PC) breach in relation to shared perceptions of complementary and supplementary fit to explain why some teams perform better than other teams. We collected three repeated survey measures in a sample of 128 respondents across 46 teams. After having made sure that we met all statistical criteria, we aggregated our focal variables to the team-level and analyzed our data by means of a longitudinal three-wave autoregressive moderated-mediation model in which each relationship was one-time lag apart. We found that shared perceptions of PC breach were directly negatively related to team output and negatively related to perceived team member effectiveness through a decrease in shared perceptions of supplementary fit. However, we also demonstrated a beneficial process in that shared perceptions of PC breach were positively related to shared perceptions of complementary fit, which in turn were positively related to team output. Moreover, best team output appeared in teams that could combine high shared perceptions of complementary fit with modest to high shared perceptions of supplementary fit. Overall, our findings seem to indicate that in terms of team output there may be a bright side to perceptions of PC breach and that perceived person-team fit may play an important role in this process.