Path-programmable logic

Journal ArticlePath-Programmable Logic (PPL) is a structured IC design methodology under development at the University of Utah. PPL employs a sea-of-wires approach to design. In PPL, design is done entirely using cells for both functionality and interconnect. PPL cells may have modifiers that change either their connections or functionality. Wires in the PPL design plane are segmentable at any cell boundary. PPL is implemented as a set of cell libraries (NMOS, CMOS, and GaAs) and a suite of tools that permit the designer to create, modify, simulate and check PPL circuit designs and to generate mask data for them. PPL exhibits little or no area penalty with respect to full custom densities while permitting system design to be done more rapidly than with gate arrays or standard cells. PPL may be implemented as a sea-of-gates gate array to provide fast turnaround

EEG Source Imaging: A Practical Review of the Analysis Steps

The electroencephalogram (EEG) is one of the oldest technologies to measure neuronal activity of the human brain. It has its undisputed value in clinical diagnosis, particularly (but not exclusively) in the identification of epilepsy and sleep disorders and in the evaluation of dysfunctions in sensory transmission pathways. With the advancement of digital technologies, the analysis of EEG has moved from pure visual inspection of amplitude and frequency modulations over time to a comprehensive exploration of the temporal and spatial characteristics of the recorded signals. Today, EEG is accepted as a powerful tool to capture brain function with the unique advantage of measuring neuronal processes in the time frame in which these processes occur, namely in the sub-second range. However, it is generally stated that EEG suffers from a poor spatial resolution that makes it difficult to infer to the location of the brain areas generating the neuronal activity measured on the scalp. This statement has challenged a whole community of biomedical engineers to offer solutions to localize more precisely and more reliably the generators of the EEG activity. High-density EEG systems combined with precise information of the head anatomy and sophisticated source localization algorithms now exist that convert the EEG to a true neuroimaging modality. With these tools in hand and with the fact that EEG still remains versatile, inexpensive and portable, electrical neuroimaging has become a widely used technology to study the functions of the pathological and healthy human brain. However, several steps are needed to pass from the recording of the EEG to 3-dimensional images of neuronal activity. This review explains these different steps and illustrates them in a comprehensive analysis pipeline integrated in a stand-alone freely available academic software: Cartool. The information about how the different steps are performed in Cartool is only meant as a suggestion. Other EEG source imaging software may apply similar or different approaches to the different steps