An efficiently implementable maximum likelihood decoding algorithm for tailbiting codes

Convolutional tailbiting codes are widely used in mobile systems to perform error-correcting strategies of data and control information. Unlike zero tail codes, tailbiting codes do not reset the encoder memory at the end of each data block, improving the code efficiency for short block lengths. The objective of this work is to propose a low-complexity maximum likelihood decoding algorithm for convolutional tailbiting codes based on the Viterbi algorithm. The performance of the proposed solution is compared to that of another maximum likelihood decoding strategy which is based on the A* algorithm. The computational load and the memory requirements of both algorithms are also analysed in order to perform a fair comparison between them. Numerical results considering realistic transmission conditions show the lower memory requirements of the proposed solution, which makes its implementation more suitable for devices with limited resources.     

A survey on nonlinear analog-to-digital converters

This paper presents a survey on Nonlinear Analog-to-Digital converters (ADC). This class of converters is extremely relevant in applications where there is a need for non-uniform quantization characteristic, for example, some specific applications in the areas of light detection, hearing aid, nuclear physics, image acquisition, communication systems, etc. This survey outlines the state-of-the-art Nonlinear ADC topologies, such as, floating point, logarithmic, piecewise linear and oversampled nonlinear converters, and discusses their performance and advantages in terms of their applications.     

Epitope-Imprinted Nanoparticles as Transforming Growth Factor-β3 Sequestering Ligands to Modulate Stem Cell Fate

Growth factors (GFs) are biomolecules with potent biological effects but inherent limitations hinder their potential as therapeutic agents and cell culture supplements in tissue engineering and regenerative medicine (TERM). Biomaterials that sequester endogenous GFs by affinity binding might circumvent such limitations and thus are being increasingly investigated. Here, molecularly imprinted nanoparticles (MINPs) are proposed as specific abiotic ligands for GFs. As a proof of concept, a conformational epitope of transforming growth factor-β3 (TGF-β3) is designed and surface imprinted onto polyacrylamide-based nanoparticles by inverse microemulsion polymerization. It is found that, depending on the polymerization mixture composition, MINPs can recognize and preferentially bind TGF-β3, either in noncompetitive assays or from a complex human fluid (platelet lysate). Substrates functionalized with MINPs are then used for 2D culture of adipose-derived stem cells. Remarkably, gene and protein expression profiles show a marked upregulation of SOX-9, suggesting activation of TGF-β3 signaling pathways without requiring supplementation with exogenous GF. Likewise, culturing these cells in pellets incorporating MINPs previously incubated with platelet lysate results in higher collagen II-rich matrix deposition, compared to pellets incorporating non-imprinted nanoparticles. In summary, results suggest MINPs can be used as cost-effective, stable, and scalable alternative abiotic GF ligands to guide cell fate in TERM applications.     

A 0.8 μm CMOS testable switched-capacitor filter for video frequency applications

This paper presents the design of a fifth-order low-pass elliptic filter that employs a parallel connection of two all-pass sections to satisfy specifications commonly used in video frequency applications. Operating with a sampling frequency of 16 MHz, the IC prototype was implemented in a standard double-poly CMOS 0.8 μm process. The experimental verification showed a passband frequency deviation smaller than 0.08 dB up to the passband edge frequency of 3.4 MHz, and an output noise power of 0.97 ${\mu {\rm V}_{\rm RMS}}/{\sqrt {Hz}}This paper presents the design of a fifth-order low-pass elliptic filter that employs a parallel connection of two all-pass sections to satisfy specifications commonly used in video frequency applications. Operating with a sampling frequency of 16 MHz, the IC prototype was implemented in a standard double-poly CMOS 0.8 μm process. The experimental verification showed a passband frequency deviation smaller than 0.08 dB up to the passband edge frequency of 3.4 MHz, and an output noise power of 0.97 , resulting in a dynamic range of 49.1 dB. The filter structure enables multiple fault detection and suits modern automated testing configurations to allow accurate estimation of the actually implemented transfer function parameters, an issue of increasing importance in VLSI circuit design. The relative area required for testing the fifth-order filter is only 8% of the total filter area, and decreases as the filter order increases. Jorge Morales Ca?ive was born in Cienfuegos, Cuba, in 1963. He received the B.Sc. and M.Sc. degrees from the Technical University of San Petersburg, Russia, in 1986 and 1988, respectively, and the D.Sc. degree from the Federal University of Rio de Janeiro, Brazil, in 1991, all in electrical engineering. From 1988 to 1994, he worked at CEADEN, in Havana, Cuba, on the development of nuclear equipments. From 1994 to 1997, he worked at INOR, in Havana, Cuba, on the research and development of acquisition systems and image processing for nuclear medicine. His research interests are in the areas of analog and digital signal processing. Antonio Petraglia (S’89-M’91-SM’99) received the Engineer and M.Sc. degrees from the Federal University of Rio de Janeiro (UFRJ), Brazil, in 1977 and 1982, respectively, and the Ph.D. degree from the University of California, Santa Barbara (UCSB), in 1991, all in electrical engineering. In 1979, he joined the Faculty of UFRJ as an Associate Professor of electrical engineering, where he served as a Co-Chair in the Department of Electronic Engineering from 1982 to 1984. During the second semester of 1991, he was a post-Doctoral researcher with the Department of Electrical and Computer Engineering at UCSB. Since 1992 he has been on the faculty of the Program for Post-Graduate Engineering at UFRJ, where in 1997 he established the Laboratory for the Processing of Analog and Digital Signals. From March 2001 through March 2002 he was a Visiting Scholar with the Electrical Engineering Department at the University of California, Los Angeles. He has been involved in teaching and research activities in the areas of analog and digital signal processing, and in mixed analog-digital integrated circuit design. He is a distinguished member of the Brazilian Millenium Group in Nanoelectronics and Microelectronics in 2006-2008. Dr. Petraglia served as an Associate Editor for the IEEE Transactions on Circuits and Systems-II: Analog and Digital Signal Processing in 2002–2003 Mariane Rembold Petraglia (M’97) received the B.Sc. degree in electronic engineering from the Federal University of Rio de Janeiro, Brazil, in 1985, and the M.Sc. and Ph.D. degrees in electrical engineering from the University of California, Santa Barbara, in 1988 and 1991, respectively. From 1992 to 1993, she was with the Department of Electrical Engineering, Catholic University of Rio de Janeiro, Brazil. Since 1993, she has been with the Department of Electronic Engineering and with the Program of Electrical Engineering, COPPE, at the Federal University of Rio de Janeiro, where she is presently an Associate Professor. From March 2001 to February 2002, she was a Visiting Researcher with the Adaptive Systems Laboratory, at the University of California, Los Angeles. Her research interests are in adaptive signal processing, multirate systems, and image processing. Dr. Petraglia is a member of Tau Beta Pi, and a distinguished member of the Brazilian Millenium Group in Nanoelectronics and Microelectronics in 2006–2008. She is serving as an Associate Editor for the IEEE Transactions on Signal Processing since Nov. 2004.     

High-voltage LDMOS transistors fully compatible with a deep-submicron 0.35 μm CMOS process

This work presents the design of LDMOS transistors fully compatible with a standard CMOS process, only requiring mask layout manipulation. A conventional 0.35 μm CMOS process was elected to demonstrate the viability of the approach. The prototyped LDMOS transistor exhibits a breakdown voltage of 24 V, which represents an improvement of 31% when compared with the high-voltage extended-drain NMOS available in the process library, while other static parameters remain in the same range. Furthermore, this solution enables the CMOS integration of a high-voltage pass-transistor, as a consequence of the formation of an isolated lightly doped p-type region inside the n-well.     

SDN-based architecture for providing quality of service to high-performance distributed applications

The specification of quality of service (QoS) requirements in most of the existing networks is still challenging. In part, traditional network environments are limited by their high administrative cost, although software-defined networks (SDNs), a newer network paradigm, simplify the management of the whole network infrastructure. In fact, SDN provides a simple way to effectively develop QoS provisioning mechanisms. In this sense, we explore the SDN model and its flexibility to develop a QoS provisioning architecture. Through the use of our new architecture, network operators are able to specify QoS levels in a simple way. Each individual data flow can be addressed, and the architecture we propose also negotiates the QoS requirements between the network controller and applications. On the other hand, the network controller continuously monitors the network environment. Then, it allocates network elements resources and prioritizes traffic, adjusting the network performance. We evaluate the feasibility of our QoS provisioning mechanism by presenting three experimental setups under realistic scenarios. For example, for a given scenario where we evaluate file transfers, our results indicate that the additional SDN modules present negligible overhead. Moreover, for a given setup, we observe a reduction of up to 82% in the file transfer times.     

In search of computer-aided social support in non-communicable diseases care

Non-communicable diseases burden is well-known and care for these diseases goes beyond patients’ engagement, extending to their family, friends, and acquaintances. The ability of social relations in alleviating the harmful effects of health risks is known as social support. Computing can be used to promote social support to enhance the care of non-communicable diseases. However, it is unclear how computing obtains such enhancement. This paper presents a systematic review, in the form of a mapping study, aiming to answer how computing enhances non-communicable diseases care by using social data and by promoting social support. It also looks for available computing models focused on social support promotion in non-communicable diseases care. The study was guided by a two-phase process review, resulting in 38 reviewed papers from journals, conferences, and chapters in the period from 2010 to 2016. In general, the reviewed papers focus on controlled trials, frameworks and systems, knowledge discovery, simulation models or social media usage analysis. Knowledge discovery was the predominant subject, followed by social media usage analysis, and frameworks and systems.     

Conjugated Polymers: High‐Resolution Scanning Near‐Field Optical Lithography of Conjugated Polymers (Adv. Funct. Mater. 17/2010)

The fabrication of high‐resolution nanostructures in both poly(p‐phenylene vinylene), PPV, and a crosslinkable derivative of poly(9,9′‐dioctylfluorene), F8, using scanning near‐field optical lithography, is reported. The ability to draw complex, reproducible structures with 65000 pixels and lateral resolution below 60 nm (< λ/5) is demonstrated over areas up to 20 μm × 20 μm. Patterning on length‐scales of this order is desirable for realizing applications both in organic nanoelectronics and nanophotonics. The technique is based on the site‐selective insolubilization of a precursor polymer under exposure to the confined optical field present at the tip of an apertured near‐field optical fiber probe. In the case of PPV, a leaving‐group reaction is utilized to achieve insolubilization, whereas the polyfluorene is insolubilized using a photoacid initiator to create a crosslinked network in situ. For PPV, resolubilization of the features is observed at high exposure energies. This is not seen for the crosslinked F8 derivative, r‐F8Ox, allowing us to pattern structures up to 200 nm in height.     

Vitamins as Active Agents for Highly Emissive and Stable Nanostructured Halide Perovskite Inks and 3D Composites Fabricated by Additive Manufacturing

The use of non-toxic and low-cost vitamins like α-tocopherol (α-TCP, vitamin E) to improve the photophysical properties and stability of perovskite nanocrystals (PNCs), through post-synthetic ligand surface passivation, is demonstrated for the first time. Especially interesting is its effect on CsPbI₃ the most unstable inorganic PNC. Adding α-TCP produces that the photoluminescence quantum yield (PLQY) of freshly prepared and aged PNCs achieves values of ≈98% and 100%, respectively. After storing 2 months under ambient air and 60% relative humidity, PLQY is maintained at 85% and 67%, respectively. α-TCP restores the PL features of aged CsPbI₃ PNCs, and mediates the radiative recombination channels by reducing surface defects. In addition, the combination of α-TCP and PNCs facilitates the chemical formulation to prepare PNCs-acrylic polymer composites processable by additive manufacturing. This enables the development of complex shaped parts with improved luminescent features and long-term stability for 4 months, which is not possible for non-modified PNCs. A PLQY ≈92% is reached in the 3D printed polymer/PNC composite, the highest value obtained for a red-emitting composite solid until now as far as it is known. The passivation shell provided by α-TCP makes that PNCs inks do not suffer any degradation process avoiding the contact with the environment and preserve their properties after reacting with polar monomers during composite polymerization.