A floating-gate MOS learning array with locally computed weightupdates

We have demonstrated on-chip learning in an array of floating-gate MOS synapse transistors. The array comprises one synapse transistor at each node, and normalization circuitry at the row boundaries. The array computes the inner product of a column input vector and a stored weight matrix. The weights are stored as floating-gate charge; they are nonvolatile, but can increase when we apply a row-learn signal. The input and learn signals are digital pulses; column input pulses that are coincident with row-learn pulses cause weight increases at selected synapses. The normalization circuitry forces row synapses to compete for floating-gate charge, bounding the weight values. The array simultaneously exhibits fast computation and slow adaptation: The inner product computes in 10 μs, whereas the weight normalization takes minutes to hours     

Evaluation of the cellulolytic capacity of Ascobolus furfuraceus (Fungi, Ascomycotina)

Growth kinetic variables (dry weight, mycelial protein, extracellular protein and pH evolution) were measured in Ascobolus furfuraceus cultures either with soluble cellulose (CMC) or crystalline cellulose as only carbon sources. When growing on CMC the mycelial protein production reached a maximum at 14 days, while the extracellular protein was maximal at 17 days. On crystalline cellulose more delay was observed (4 and 14 days, respectively). Straight lineal correspondence (r = 0.9883) was observed between the extracellular protein production and enzymatic activity kinetics, showing parallel behavior of these variables. When the biomass and extracellular protein production rates were analysed, the maxima were observed at diverse growth stages. For CMC, the dry weight production rythm precedes the cellulolytic system liberation rythm (maxima at 9 and 14 days, respectively). When crystalline cellulose was the substrate, the maximal rates were inverse, 16th day for biomass production rythm and 12th day for enzyme release rythm. On the basis of such tests and analyses, a model to explain cellulose degration by A. furfuraceus, is proposed.     

Measurement of ultralow gate tunneling currents using floating-gate integrator technique

We report for the first time that a gate tunneling current measurement sensitivity better than 3/spl times/10/sup -22/ A has been achieved by using a floating-gate integrator technique. The technique involves monitoring the charge change in the floating-gate integrated with an on-chip op-amp and an on-chip feedback capacitor. We used this technique to study the stress-induced leakage current (SILC) and its cycling dependence of 70 /spl Aring/ oxides in the direct tunneling region at oxide voltage as low as 1.9 V. The technique has been validated through correlation to direct measurement on MOSFET arrays and theoretical calculations. The measured SILC current is modeled with an Inelastic trap-assisted tunneling model.     

A Complementary Pair of Four-Terminal Silicon Synapses

We have developed a complementary pair of pFETand nFET floating-gate silicon MOS transistors foranalog learning applications. The memory storage is nonvolatile;hot-electron injection and electron tunneling permit bidirectionalmemory updates. Because these updates depend on both the storedmemory value and the transistor terminal voltages, the synapsescan implement a learning function. We have derived a memory-updaterule for both devices, and have shown that the synapse learningfollows a simple power law. Unlike conventional EEPROMs, thesynapses allow simultaneous memory reading and writing. Synapsetransistor arrays can therefore compute both the array output,and local memory updates, in parallel. We have fabricated prototypesynaptic arrays; because the tunneling and injection processesare exponential in the transistor terminal voltages, the writeand erase isolation between array synapses is better than 0.01 percentThe synapses are small, and typically are operated at subthresholdcurrent levels; they will permit the development of dense, low-powersilicon learning systems.     

Computer electronics meet animal brains

Although digital computers and nerve tissue both use voltage waveforms to transmit and process information, engineers and neurobiologists have yet to cohesively link the electronic signaling of digital computers with the electronic signaling of nerve tissue in freely behaving animals. Recent advances will finally let us link computer circuitry to neural cells in live animals and, in particular, to reidentifiable cells with specific, known neural functions. By enabling neuroscientists to better understand the neural basis of behavior, these devices may someday lead to neural prosthetics, hardware-based human-computer interfaces, and artificial systems that incorporate principles of biological intelligence.     

A 19.2 GOPS mixed-signal filter with floating-gate adaptation

We have built a 48-tap, mixed-signal adaptive FIR filter with 8-bit digital input and an analog output with 10 bits of resolution. The filter stores its tap weights in nonvolatile analog memory cells using synapse transistors, and adapts using the least mean square (LMS) algorithm. We run the input through a digital tapped delay line, multiply the digital words with the analog tap weights using mixed-signal multipliers, and adapt the tap coefficients using pulse-based feedback. The accuracy of the weight updates exceeds 13 bits. The total die area is 2.6 mm/sup 2/ in a 0.35-/spl mu/m CMOS process. The filter delivers a performance of 19.2 GOPS at 200 MHz, and consumes 20 mW providing a 6-mA differential output current.     

Review of Brain injury casebook: Methods for re-integration to home, school, and community.

Reviews the book, Brain injury casebook: Methods for re-integration to home, school, and community by Dorrie Rapp (1986). Any professional who has been part of the difficult process of helping a brain injured individual re-integrate into life will undoubtedly find Dr. Rapp's book useful and timely. Recent head injury seminars have begun to focus directly upon the myriad of problems facing the traumatically brain injured when he or she begins to deal with life after traditional rehabilitation. Through the use of actual and often poignant case studies, Dr. Rapp illustrates the flexibility, creativity, and persistence necessary when working with the traumatically brain injured and their families. As we begin to grasp the complexity of re-integration for the traumatically brain injured individual, more documentation of the comprehensiveness of the problem needs to be published. Professionals working with the brain injured will find both support and new ideas from reading Dr. Rapp's book. The only criticism is that it does not delve into vocational issues which, by far, comprise a large portion of reintegration problems. However, professionals, care providers, brain injured individuals, families, schools, funding agencies, and employers can all obtain an excellent overview of the complexity of successful re-integration following traumatic brain injury. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Breast Cancer and Microcalcifications: An Osteoimmunological Disorder?

The presence of microcalcifications in the breast microenvironment, combined with the growing evidences of the possible presence of osteoblast-like or osteoclast-like cells in the breast, suggest the existence of active processes of calcification in the breast tissue during a woman’s life. Furthermore, much evidence that osteoimmunological disorders, such as osteoarthritis, rheumatoid arthritis, or periodontitis influence the risk of developing breast cancer in women exists and vice versa. Antiresorptive drugs benefits on breast cancer incidence and progression have been reported in the past decades. More recently, biological agents targeting pro-inflammatory cytokines used against rheumatoid arthritis also demonstrated benefits against breast cancer cell lines proliferation, viability, and migratory abilities, both in vitro and in vivo in xenografted mice. Hence, it is tempting to hypothesize that breast carcinogenesis should be considered as a potential osteoimmunological disorder. In this review, we compare microenvironments and molecular characteristics in the most frequent osteoimmunological disorders with major events occurring in a woman’s breast during her lifetime. We also highlight what the use of bone anabolic drugs, antiresorptive, and biological agents targeting pro-inflammatory cytokines against breast cancer can teach us.     

EPCglobal第二代RFID标准

众所周知,从二战开始,类似RFI D技术的雷达技术就得到了应用,RFID技术可谓历史悠久.但和条码技术相比,RFID的应用为什么远远没有达到其潜力呢?其中一个主要的原因就是相关标准的发展情况.就目前的情况而言,RFID不是没有标准,而是标准太多,缺乏一个统一的、全球性的标准.     

Reliability of pFET EEPROM with 70-/spl Aring/ tunnel oxide manufactured in generic logic CMOS Processes

We investigate the reliability of pFET-based EEPROMs with 70-/spl Aring/ tunneling oxides fabricated in standard foundry 0.35-/spl mu/m, 0.25-/spl mu/m, and 0.18-/spl mu/m logic CMOS processes. The floating-gate memory cell uses Fowler-Nordheim tunneling erase and impact-ionization generated hot-electron injection for programming. We show that charge leakage is dominated by the leakage through interlayer dielectrics. We propose a retention model and show the data retention lifetime exceeds 10 years. These results demonstrate the feasibility of producing nonvolatile memory using standard logic processes that have a 70-/spl Aring/ oxide.