RESUMEN
Analog in-memory computing synaptic devices are widely studied for efficient implementation of deep learning. However, synaptic devices based on resistive memory have difficulties implementing on-chip training due to the lack of means to control the amount of resistance change and large device variations. To overcome these shortcomings, silicon complementary metal-oxide semiconductor (Si-CMOS) and capacitor-based charge storage synapses are proposed, but it is difficult to obtain sufficient retention time due to Si-CMOS leakage currents, resulting in a deterioration of training accuracy. Here, a novel 6T1C synaptic device using only n-type indium gaIlium zinc oxide thin film transistor (IGZO TFT) with low leakage current and a capacitor is proposed, allowing not only linear and symmetric weight update but also sufficient retention time and parallel on-chip training operations. In addition, an efficient and realistic training algorithm to compensate for any remaining device non-idealities such as drifting references and long-term retention loss is proposed, demonstrating the importance of device-algorithm co-optimization.
RESUMEN
The development and application of a new ion detection method based on the electroacoustic (EA) effect is described. An EA signal, produced by applying a pulsed-type electric field to an electrolyte solution in an electroacoustic cell, is dependent on the electrical and thermal properties of the electrolyte and can be detected by using a conventional gas microphone system. The EA signals, generated in this fashion, are proportional to the square of the amplitude of the pulsed-type electric field and show an inverse dependence on the modulated frequency, as found in other acoustic detection systems. The results of this study demonstrate that the EA signals observed with the new system display a linear dependence on the concentration of the electrolyte over a 3 order-of-magnitude concentration range (ca. 10(-7)-10(-4) M). The detection limit of this system was shown to be as low as 29.9 ppb for an aqueous solution of HCl. The results also indicate that the EA signal is proportional to the equivalent conductivity of electrolytes in aqueous solution. As a consequence, the new method has the potential of being used as a universal detector for ions in solutions. An important property of this detection system is that it can be applied to in situ ion detection, and as a result, it can be employed in kinetic studies to follow the progress of ionic chemical reactions.
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[structure: see text] To develop novel consecutive beta- and gamma-turn mimetics, we designed and characterized alpha-aminooxy tripeptides (trimers) consisting of oxanipecotic acid dimer and alpha-aminooxy acid. According to FT-IR and NMR data, as well as ab initio quantum calculations, the trimers adopted unusual folded structures with consecutive beta- and gamma-turnlike conformations.
Asunto(s)
Imitación Molecular , Péptidos/química , Dimerización , Espectroscopía de Resonancia Magnética , Estructura Molecular , Péptidos/síntesis química , Estructura Secundaria de Proteína , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
Ab initio calculation and circular dichroism experiments reveal that Oxa-oligomers adopted pronounced non-hydrogen-bonded helical structures.
Asunto(s)
Ácidos Nipecóticos/química , Polímeros/química , Materiales Biomiméticos/química , Dicroismo Circular , Modelos Moleculares , Estructura Secundaria de Proteína , Estereoisomerismo , TermodinámicaRESUMEN
Image enhancement is an important issue in digital image processing. Various approaches have been developed to solve image enhancement problems, but most of them require deep expert knowledge to design appropriate image filters. To automatically design a filter, we propose a novel approach based on the genetic algorithm that optimizes a set of standard filters by determining their types and order. Moreover, the proposed method is able to manage various types of noise factors. We applied the proposed method to local and global image enhancement problems such as impulsive noise reduction, interpolation, and orientation enhancement. In terms of subjective and objective evaluations, the results show the superiority of the proposed method.
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Algoritmos , Procesamiento de Imagen Asistido por Computador/métodos , Modelos Genéticos , Reconocimiento de Normas Patrones Automatizadas/métodos , Distribución NormalRESUMEN
A case of melorheostosis, which affected upon left upper extremity as monomelic type, was experienced at the Department of Orthopedic Surgery of Seoul National University Hospital in May 1971. We report this case with reference because of the rarity of melorheostosis and an addition of the case, a case with the literal reference is persented.
Asunto(s)
Melorreostosis , Ortopedia , Seúl , Extremidad SuperiorRESUMEN
10 cases of tuberculosis of the greater trochanter of the femur were treated at the Department of Orthopedic Surgery, Seoul National University Hospital from Jan. 1964 to Jun. 1971 with following results; 1) Duration of onset was more than 2 years in 7 cases and tuberculous foci of other organ were noted in 4 cases. 2) Bony destruction on the greater trochanter was observed in all cases and marked synovial thickening was combined in 4 cases. 3) Radical curettage or resection of bony focus of the greater trochanter were carried out in all cases with excellent result except 1 case in which reoperation was necessary 4 years later.