Folding Technique Research Articles

Architectural Design of 32 Bit Polar Encoder

The rapid development in the digital circuit design enhances the applications on very large scale integration era. Encoders are one among the digital circuits found in all communication systems. The polar encoding is mainly meant for its channel achieving property. It finds its application in communications, sensing and information theory. This coding proposed by Erdal Arikan is significant because of its zero error floors and simple architecture for hardware implementation. In this paper, a folded polar encoder is designed to start from the fully parallel architecture and proceeds with its data flow graph, delay requirement calculation, lifetime analysis and register allocation, which results in a very large scale integration architecture with minimum hardware utilization. The results are simulated for 4 and 8 parallel folded 32-bit polar encoder using Xilinx 14.6 ISIM and implemented in Virtex 5 field programmable gate array. A comparison is made on fully parallel and various folding techniques based on their resource utilization.

Gum Sensor: A Stretchable, Wearable, and Foldable Sensor Based on Carbon Nanotube/Chewing Gum Membrane.

Presented in this work is a novel and facile approach to fabricate an elastic, attachable, and cost-efficient carbon nanotube (CNT)-based strain gauge which can be efficiently used as bodily motion sensors. An innovative and unique method is introduced to align CNTs without external excitations or any complicated procedure. In this design, CNTs are aligned and distributed uniformly on the entire chewing gum by multiple stretching and folding technique. The current sensor is demonstrated to be a linear strain sensor for at least strains up to 200% and can detect strains as high as 530% with a high sensitivity ranging from 12 to 25 and high durability. The gum sensor has been used as bodily motion sensors, and outstanding results are achieved; the sensitivity is quite high, capable of tracing slow breathing. Since the gum sensor can be patterned into various forms, it has wide applications in miniaturized sensors and biochips. Interestingly, we revealed that our gum sensor has the ability to monitor humidity changes with high sensitivity and fast resistance response capable of monitoring human breathing.

A 6-bit 2.5-GS/s Time-Interleaved Analog-to-Digital Converter Using Resistor-Array Sharing Digital-to-Analog Converter

This paper presents a 6-bit 2.5-GS/s time-interleaved (TI) successive-approximation-register (SAR) analog-to-digital converter (ADC) that uses a resistor-array sharing digital-to-analog converter (RASD). By applying the input folding technique in the input stage and utilizing the flash-assisted TI-SAR ADC with the proposed RASD, the static power dissipation is reduced by 69%. ON-chip and OFF-chip calibration techniques are used to compensate the interchannel error sources. The prototype was fabricated in a 65-nm CMOS process technology. The peak integral nonlinearity and differential nonlinearity are measured as 0.52 and 0.51 LSB, respectively. At 2.5 GS/s, a signal-to-noise and distortion ratio (SNDR) of 18.6/31.9 dB and a spurious-free dynamic range (SFDR) of 23.7/42.1 dBc are measured before and after the calibration at the Nyquist input frequency with 1 Vpp-diff input signal, and the figure of merit is 0.27 pJ/conversion-step. This chip consumes 22 mW at 1.2-V supply and occupies 0.27-mm2 area.

Evaluating the quality of bed length and area balance in 2D structural restorations

The use of structural restorations as a tool to investigate structural evolution, fault and horizon relationships, and validity of interpretation has been widespread for more than four decades. The first efforts relied on hand-drafted bed-length measurements of commonly constant thickness stratigraphic units and were typically applied to fold-and-thrust belt settings. The advent of computer-assisted section construction and restoration software allowed for the assessment of more complicated structural interpretations by applying several new methods for forward and inverse strain transformation. Although quicker and more accurate than hand-drafted, the results of computer-aided structural modeling still need to be interrogated. We have reviewed the different strain transformation (restoration) methods available and their implications for bed length and area conservation: (1) fundamental simple shear and its two basic modes (flexural slip and inclined shear inversions), (2) fault-related folding techniques, and (3) the effects of mechanical stratigraphy and compaction. The assessment of the restoration methods was illustrated by examining two examples: the Mount Crandell Duplex Structure in southern Alberta and the Virgin River Extensional Basin in the southeast of Nevada. For both examples, we developed tables listing and confirming the deformed/restored state line lengths and areas. We believe that such tables should be provided for any strain transformation exercise, along with the restoration results as parameters for quality control, to prevent over- and underestimations that deviate more than 5% from the initial interpretation.

Multidimensional folding for sinusoidal order selection

Estimation of the number of harmonics in multidimensional sinusoids is studied in this paper. The ESTimation ERror (ESTER) is a subspace based detection approach that is robust against colored noise. However, the number of signals it can detect is very limited. To improve the identifiability, we propose to combine the multidimensional folding (MDF) techniques with ESTER for multidimensional sinusoidal order selection. Our algorithm development is inspired by the shift invariance properties of the two matrix slices resulting from multidimensional folding and unfolding, which have been exploited to extract the spatial frequencies in the literature. The maximum identifiable number of signals of the MDF-ESTER is of the order of magnitude of product of the lengths of all spatial dimensions with uniform spacing, which is significantly larger than that of the conventional multidimensional ESTER methods. Meanwhile, it inherits the robustness of the ESTER against colored noise, and performs comparably to state-of-the-art schemes when the number of signals is small.

Hetero‐Nanonet Rechargeable Paper Batteries: Toward Ultrahigh Energy Density and Origami Foldability

Forthcoming smart energy era is in strong pursuit of full‐fledged rechargeable power sources with reliable electrochemical performances and shape versatility. Here, as a naturally abundant/environmentally friendly cellulose‐mediated cell architecture strategy to address this challenging issue, a new class of hetero‐nanonet (HN) paper batteries based on 1D building blocks of cellulose nanofibrils (CNFs)/multiwall carbon nanotubes (MWNTs) is demonstrated. The HN paper batteries consist of CNF/MWNT‐intermingled heteronets embracing electrode active powders (CM electrodes) and microporous CNF separator membranes. The CNF/MWNT heteronet‐mediated material/structural uniqueness enables the construction of 3D bicontinuous electron/ion transport pathways in the CM electrodes, thus facilitating electrochemical reaction kinetics. Furthermore, the metallic current collectors‐free, CNF/MWNT heteronet architecture allows multiple stacking of CM electrodes in series, eventually leading to user‐tailored, ultrathick (i.e., high‐mass loading) electrodes far beyond those accessible with conventional battery technologies. Notably, the HN battery (multistacked LiNi0.5Mn1.5O4 (cathode)/multistacked graphite (anode)) provides exceptionally high‐energy density (=226 Wh kg−1 per cell at 400 W kg−1 per cell), which surpasses the target value (=200 Wh kg−1 at 400 W kg−1) of long‐range (=300 miles) electric vehicle batteries. In addition, the heteronet‐enabled mechanical compliance of CM electrodes, in combination with readily deformable CNF separators, allows the fabrication of paper crane batteries via origami folding technique.

Unraveling metamaterial properties in zigzag-base folded sheets.

Creating complex spatial objects from a flat sheet of material using origami folding techniques has attracted attention in science and engineering. In the present work, we use the geometric properties of partially folded zigzag strips to better describe the kinematics of known zigzag/herringbone-base folded sheet metamaterials such as Miura-ori. Inspired by the kinematics of a one-degree of freedom zigzag strip, we introduce a class of cellular folded mechanical metamaterials comprising different scales of zigzag strips. This class of patterns combines origami folding techniques with kirigami. Using analytical and numerical models, we study the key mechanical properties of the folded materials. We show that our class of patterns, by expanding on the design space of Miura-ori, is appropriate for a wide range of applications from mechanical metamaterials to deployable structures at small and large scales. We further show that, depending on the geometry, these materials exhibit either negative or positive in-plane Poisson's ratios. By introducing a class of zigzag-base materials in the current study, we unify the concept of in-plane Poisson's ratio for similar materials in the literature and extend it to the class of zigzag-base folded sheet materials.

A low-cost transcervical laryngeal injection trainer.

To develop a low-cost, easy-to-construct model for education in transcervical laryngeal injection techniques. To validate the simulator among both fellowship-trained laryngologists and otolaryngology resident learners. Survey. A transcervical laryngeal injection model was constructed. Fourteen otolaryngology residents used the model to practice vocal fold injection techniques. Survey feedback was obtained from all residents. Most learners agreed or strongly agreed that the simulator was easy to use (93%), was a good method to learn transcervical laryngeal injection technique (79%), improved their confidence with the procedure (78%), and could be applied to patients (72%). One hundred percent of the learners agreed or strongly agreed that they would recommend the simulator to other learners. Residents can be taught transcervical laryngeal injection techniques with a low-cost, easily constructed simulator prior to treating patients. This allows for a low-stress environment in which the learner can practice injection techniques. Resident feedback about the transcervical laryngeal injection simulator was very positive, including unanimous recommendation for use in other learners. N/A.

Design and assessment of composite civil moderate code structure for efficient global positioning system L2 civil signal acquisition

In global positioning system modernisation, a new civil signal namely L2C signal has been broadcast since 2005. Compared with the widely used C/A code signal, although the new signal provides lots of advantages such as better acquisition and tracking performances, the used civil moderate (CM) code and civil long code have much longer periods than C/A code and they make L2C signal acquisition challengeable. Although previous acquisition methods are effective, their computational complexities are still high. To this end, in the study, a composite CM (CCM) code structure is developed by reconstructing the previous return-to-zero CM (RZCM) code through the previous folding technique. Then the CCM code is comprehensively assessed. Compared with the RZCM code, the developed CCM code has following advantages. It can be implemented by small scale FFT block, which is desirable for resource-limited L2C receivers; it is more robust against navigation data and carrier Doppler, and performs more reliable detection performance; for normally received L2C signal, which is usually not <42 dBHz, it spends less time on acquisition. Theoretical and simulation results demonstrate the advantages.

Non‐singular sequence folding‐based pseudorandom key generation algorithm for cryptographic processor

AbstractIn this paper, a new algorithm to construct the non‐linear‐based Boolean function using non‐singular sequence folding technique is proposed to generate pseudorandom binary key sequence for cryptographic processor. Unlike the conventional methodology to generate recursive pseudorandom nibble of 15 (60‐bit) from minimum seed of four bits, the proposed algorithm has the novelty to generate non‐recursive pseudorandom nibble of 63 (252‐bit) from the same minimum seed of four bits. In this proposed algorithm, a given binary sequence is converted to de Bruijn sequence and folded to minimum state with the strategy of binary encoding, which supports to determine the non‐linear Boolean function. Further, the next state functions with minimum logic complexity is formulated using the algebraic normal form to generate non‐recursive pseudorandom binary sequence. The key stream analysis is performed, and randomness tests for the generated pseudorandom binary sequence (key stream) is validated using National Institute of Standards and Technology test suite. The proposed algorithm in this paper has improved in terms of sequence size and number of stages compared with existing algorithms. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Foldable Paper-Based Lithium-Ion Batteries

One of the most important aspects to enabling paper electronics are suitable and well integrated power sources. A convenient and useful aspect of paper is its ability to be folded into a multitude of shapes, such as those available by applying origami concepts, which can open the door for unprecedented types of paper electronics. Hence, the development of robust batteries that can also be folded is attractive for achieving good integration with paper-based devices. In this talk, I will discuss how paper folding techniques inspired from Japanese origami can be used to compact a Li-ion battery and increase its energy per footprint area. Full cells were prepared using Li4Ti5O12 and LiCoO2 powders deposited onto current collectors consisting of paper coated with carbon nanotubes. Folded cells showed higher areal capacities compared to the planar versions, with a 5 x 5 cell folded using the Miura-ori pattern displaying a ~14X increase in areal energy density. Furthermore, these cells could achieve extremely high levels of deformability, including foldability, bendability and twistability. This strategy represents the fusion of the art of origami, materials science, and functional energy storage devices and provides new opportunities for foldable, flexible and curvilinear electronics with new mechanical characteristics and functionalities.

3D Paper-Based Lithium-Ion Batteries Using Origami Folding Principles

Recently, there has been much interest in the development of energy storage and electronic devices using paper and textile components. The low cost, roll-to-roll fabrication methods, flexibility, and bendability of these substrates are attractive for high-performance devices. Many flexible devices demonstrated using paper or cellulose components include organic field effect transistors, RF devices, sensors, microfluidics, displays, transparent conducting films, and light-emitting diodes and 3D antennas. Specifically for energy storage and conversion applications, the ability for the power source to be intimately integrated to unconventional substrates has motivated research in flexible devices such as batteries, supercapacitors, nanogenerators, solar cells, and fuel cells. For applications such as MEMS, smart dust motes, and on-chip power, there is an increasing need for batteries with high energy areal energy due to the limited area available in the device. However, it is difficult to increase the energy per footprint area in 2D, planar devices since increasing the thickness of the active material layers also leads to a corresponding increase in resistivity and decrease in electrochemical performance. To address these issues, we have taken an approach that uses the conventional 2D planar battery platform but applies origami folding concepts typically used to fold paper into more compact shapes in order to realize a Li-ion battery with higher areal charge storage capacity. Origami paper folding techniques, namely the Miura-ori pattern, were used to compact a Li-ion battery and increase its energy per footprint area. Full cells were prepared using Li4Ti5O12 and LiCoO2 powders deposited onto paper coated with carbon nanotubes as current collectors. Our 5 x 5 folded cell was found to display a ~14X increase in areal energy density compared to the planar version.

Design of Deployable Membranes Using Conformal Mapping

This paper proposes a new method for designing the crease patterns of deployable membranes that can be wrapped up compactly. The method utilizes conformal mapping and the origami folding technique. The mapping of the flow with circulation can be used to control the angles between the fold lines, produce elements of the same shape, and maintain regularity of the fold lines. The proposed method thus enables the systematic and efficient design of complex patterns based on simple ones. The proposed method was successfully used to produce the patterns of Nojima and other extended new patterns of deployable membranes consisting of discrete equiangular spirals. The patterns were wrapped and used to form pillars such as regular polygonal, rectangular, and diamond pillars. Toward the industrial application of the proposed method, this paper also discusses pattern design for space-saving storage and to reduce the effect of thickness when using versatile materials.

Kinetic Solar Skin: A Responsive Folding Technique

The paper focuses on optimized movements analysed by means of Origami, the Japanese traditional art of paper folding. The study is a way to achieve different deployable shading systems categorized by a series of parameters that describe the strengths and weaknesses of each tessellation. Through the kinetic behaviour of Origami geometriesthe research compares simple folding diagrams with the purpose to understand the deployment at global scale and thus the potential of kinetic patterns’ morphology for application in adaptive facades. The possibilities of using a responsive folding technique to develop a kinetic surface that can change its configuration are here examined through the variation of parameters that influence kinematics’ form. Moreover, in order to perform the shape change without any external mechanical devices, the use of Shape Memory Alloy (SMA) actuators has been tested.

Efficient Audio Filter Using Folded Pipelining Architecture Based on Retiming Using Evolutionary Computation

It is important in digital signal processing (DSP) architectures to minimize the silicon area of the integrated circuits. This can be achieved by reducing the number of functional units such as adders and multipliers. In literature, folding technique is used to reduce the functional units by executing multiple algorithm operations on a single functional unit. Register minimization techniques are used to reduce the number of registers in a folded architecture. Retiming is a technique that needs to be performed before applying folding. In this paper, retiming is performed based on nature inspired evolutionary computation method. This technique generates the database of solutions from which best solution can be picked for folding further. As a part of this work, an efficient folded noise removal audio filter prototype is designed as an application example using evolutionary computation-based retiming and folding with register minimization. Folding technique will however increase the number of registers while multiplexing datapath adder and multiplier elements. Register minimization technique is used after folding to reduce the number of registers. After obtaining retimed, folded filter architecture, low level synthesis is performed which involves mapping of datapath adder and multiplier blocks to actual hardware. Various architectures of adders and multipliers are compared in area-power-performance space and depending on the user defined constraint, folded architecture with specific combination of data path elements is mapped on to hardware. A framework is designed in this paper to automate the entire process which reduces the design cycle time. All the designed filters are targeted for ASIC implementation. The results are compared and are provided as part of simulation results.

Performability Evaluation of Grid Environments Using Stochastic Reward Nets

In this paper, performance of grid computing environment is studied in the presence of failure-repair of the resources. To achieve this, in the first step, each of the grid resource is individually modeled using Stochastic Reward Nets (SRNs), and mean response time of the resource for grid tasks is computed as a performance measure. In individual models, three different scheduling schemes called random selection, non-preemptive priority, and preemptive priority are considered to simultaneously schedule local and grid tasks to the processors of a single resource. In the next step, single resource models are combined to shape an entire grid environment. Since the number of the resources in a large-scale grid environment is more than can be handled using such a monolithic SRN, two approximate SRN models using folding and fixed-point techniques are proposed to evaluate the performance of the whole grid environment. Brouwer’s fixed-point theorem is used to theoretically prove the existence of a solution to the fixed-point approximate model. Numerical results indicate an improvement of several orders of magnitude in the model state space reduction without a significant loss of accuracy.

Design Trade off and Performance Analysis of Router Architectures in Network-on-Chip

Abstract On chip interconnection networks simplify the challenges of integrating large number of processing elements. Routers are backbone of networks. Buffers and crossbar in router consumes significant area and power of network. Reducing buffers could lead to degradation of network performance. Dual Xbar router architecture combines buffered and bufferless feature to reduce buffer read/write energy with dual crossbars. While Switch folding technique introduced to reduce wire density and decrease muxes in crossbar by increasing resource utilization. In this paper, we propose Folded Dual Xbar architecture by combining the Dual Xbar and Folding technique in order to get advantages of both architectures. Performance of architectures is evaluated using OMNET++ platform under different load conditions. Simulation results shows that there is slight increase in throughput and reduction in buffer read/write energy by average 46% at high loads in proposed 2-Folded Dual Xbar as compared to conventional architecture. Proposed 3-Folded Dual Xbar results at least 16.6% increase in throughput as compared to conventional architecture with 43-45% reduced buffer read/write energy but slight increase in crossbar. Throughput of 3-Folded Dual Xbar decreased only by 5-7% as compared to Dual Xbar with distributed wire density advantage.

Graph-Based Approaches to Placement of Processing Element Networks on FPGAs for Physical Model Simulation

Physical models utilize mathematical equations to characterize physical systems like airway mechanics, neuron networks, or chemical reactions. Previous work has shown that field programmable gate arrays (FPGAs) execute physical models efficiently. To improve the implementation of physical models on FPGAs, this article leverages graph theoretic techniques to synthesize physical models onto FPGAs. The first phase maps physical model equations onto a structured virtual processing element (PE) graph using graph theoretic folding techniques. The second phase maps the structured virtual PE graph onto physical PE regions on an FPGA using graph embedding theory. A simulated annealing algorithm is introduced that can map any physical model onto an FPGA regardless of the model's underlying topology. We further extend the simulated annealing approach by leveraging existing graph drawing algorithms to generate the initial placement. Compared to previous work on physical model implementation on FPGAs, embedding increases clock frequency by 25% on average (for applicable topologies), whereas simulated annealing increases frequency by 13% on average. The embedding approach typically produces a circuit whose frequency is limited by the FPGA clock instead of routing. Additionally, complex models that could not previously be routed due to complexity were made routable when using placement constraints.

Folding method for bandwidth and directivity enhancement of meandered loop ultra‐high frequency antenna for heart failure detection system

A wideband antenna with unidirectional radiation is designed for lower ultra-high frequency (UHF) band, which is utilised in medical diagnostic systems, in addition to telecommunications, such as UHF television channels, WiMax, cognitive radio, radio frequency identification, mobile digital TV and CDMA/GSM800. In medical imaging, there are additional antenna design requirements, such as compact size, wide operating bandwidth and unidirectional radiation. A combination of dual monopole feeding, meandering and folding techniques is used to realise the required frequency band and directivity for the antenna, while reducing its size. The final design has the compact size of 0.23λ × 0.08λ × 0.08λ (λ is the wavelength of the lowest measured operating frequency of the antenna), a wide measured operating bandwidth of 50% (590–985 MHz), a peak gain of 3.6 dBi and a measured efficiency of more than 89% over the band of operation. The designed antenna is then used with a compact microwave transceiver, and proper data acquisition and processing algorithms to build a system for the early detection of congestive heart failure. The system is tested using a realistic artificial human torso.

Trends in Utilization of Vocal Fold Injection Procedures

Objectives: Office-based laryngeal procedures, vocal fold injections in particular, have become increasingly popular over the past 15 years. The purpose of this study was to examine trends in the use of different vocal fold injection techniques in the United States from 2000 to 2012 and see if they reflect this shift. Methods: The United States Part B Medicare claims database was queried from the years 2000 through 2012. The Current Procedural Terminology codes for indirect laryngoscopy with injection (31513), direct laryngoscopy with injection (31570), and direct laryngoscopy with injection, aided by telescope or operating microscope (31571) were used. For comparison, data for medialization laryngoplasty (31588) were also examined. The volume of procedures performed was tabulated for each code by year. Results: Over the time period studied, the number of non-operative laryngoscopic injections (31513, 31570) and operative medialization laryngoplasties remained constant. Operative vocal fold injection (31571) demonstrated significant, linear growth over the 12-year study period, from 744 procedures in 2000 to 4788 in 2012, an increase of over 640%. Conclusions: The dramatic increased incidence in the use of code 31571 reflects an increasing share of vocal fold injections being performed in the operating room and not in an office setting, which runs counter to the prevailing trend within laryngology of awake, office-based injection procedures. This may indicate that these procedures have become more popular over time within the otolaryngology community and are being performed increasingly by providers more comfortable with the controlled operating room setting.