Large Bit Research Articles

Antiferromagnetic Nanoscale Bit Arrays of Magnetoelectric Cr2O3 Thin Films.

Magnetism of oxide antiferromagnets (AFMs) has been studied in single crystals and extended thin films. The properties of AFM nanostructures still remain underexplored. Here, we report on the fabrication and magnetic imaging of granular 100 nm-thick magnetoelectric Cr2O3 films patterned in circular bits with diameters ranging from 500 down to 100 nm. With the change of the lateral size, the domain structure evolves from a multidomain state for larger bits to a single domain state for the smallest bits. Based on spin-lattice simulations, we show that the physics of the domain pattern formation in granular AFM bits is primarily determined by the energy dissipation upon cooling, which results in motion and expelling of AFM domain walls of the bit. Our results provide a way toward the fabrication of single domain AFM-bit-patterned memory devices and the exploration of the interplay between AFM nanostructures and their geometric shape.

WEAR MECHANISM FOR DEEP-WELLS DRILLING TOOLS

When drilling deep wells with a large diameter drill bit, it is important to ensure optimum progress with the cutting tool, effectively cutting or crushing the rock through which we are penetrating for as long as possible. When drilling a well, we encounter complex conditions at depth resulting from variables such as the strength of the rock, the load on the bit, the number of revolutions of the tool, significant temperature and pressure fluctuations and the material properties of the tools used in the drilling. The article shows how mechanisms develop due to the drilling parameters used and the complex drilling conditions, which lead to wear of the cutting unit and a decrease in efficiency. The influence of the aforementioned drilling conditions on the steel materials of the roller-cone drill bit, which is the tool we use to penetrate deeper, is reflected in the change in the material properties of the steels. These changes, which are explained in the article, lead to gradual fatigue and degradation of the materials. The wear mechanism of the cutting tool is composed of the different material properties of the steel from which the roller-cone drill bit is formed, the influence of sudden temperature changes on the steel materials and erosion processes on free, newly formed surfaces, which are the result of the erosion effect.

Interference-enhanced micro-vision-based single-shot imaging of five degrees-of-freedom error motions for ultra-precision rotary axes

The measurement of five degrees-of-freedom (5-DOF) error motions, including radial, axial, and tilt motions, is crucial for ultra-precision rotary axes, which are key components of ultra-precision machine tools and instrumentation. In this study, we propose an interference-enhanced micro-vision technique to concurrently derive the 5-DOF error motions from a single-shot two-dimensional image, which was captured by a standard industrial camera equipped with an interference objective lens. By consolidating the essential features into a single optical path, the interference-enhanced micro-vision technique ingeniously merges machine micro-vision and modified white-light interference to detect in-plane and out-of-plane motions. Numerical simulations demonstrated, the basic principle for deriving the 5-DOF error motions, and the magnification of objective lens had inconsistent effects on the measurement accuracy for the radial and tilt motions, i.e. higher magnification led to higher radial accuracy but lower tilt accuracy. As practical application, the error motion detection capability was demonstrated by simultaneously measuring the 5-DOF synchronous and asynchronous error motions for a typical air bearing spindle at rotation speeds of 8.33, 108.33, and 308.33 rpm. The synchronous errors were nearly identical at various spindle speeds. However, because of system dynamics, increased vibrations were observed to be superimposed on the basic tilt error motions as the spindle speeds increased, which were verified by the vibration marks imprinted on the turned surfaces. For the 5-DOF motion measurements, the least-square fitting using large-volume edge and greyscale data of the captured image enabled super-high resolutions, despite using a camera with a relatively large pixel size and low bit depth. These results demonstrate that the proposed interference-enhanced micro-vision technique is a simple and effective tool for measuring spatial error motions in ultra-precision rotary axes.

Flow Field Simulation of a Hydrogeological Exploration Drill Bit for Switching between Coring Drilling and Non-Coring Drilling

Drilling is one of the most commonly used techniques in hydrogeological exploration and is employed to obtain rock samples and create boreholes. During conventional drilling, it is necessary to raise all the drilling tools in the borehole when switching between coring drilling and non-coring drilling, which causes large auxiliary operation time consumption and poor drilling efficiency. Based on the structure of wireline coring tools, a large diameter modular drill bit was designed to switch between coring drilling and non-coring drilling without lifting the whole set of drilling tools. In the COMSOL simulation environment, a simulation model of the modular bit was constructed. Drilling fluid velocity and pressure characteristics flowing through the modular bit were studied. According to the analysis results, with the same input flow rate, similar velocities and lower pressure loss can be obtained in non-coring drilling as with the coring bit, and thus drilling cuttings can be removed effectively even if there are more cuttings produced in non-coring drilling than in coring drilling for a borehole drilled at the same diameter. When the outside diameter of the modular bit is 216 mm, the recommended clearance value is 9 mm or 10 mm in order to obtain lower pressure loss and larger diameter core. To generate low pressure loss and ensure bit strength, a layout with four nozzles on the internal non-coring bit is recommended. The modular bit enables fast switching between coring drilling and non-coring drilling without raising the drilling tools. The simulation model can be used for drilling parameter selection and drill bit optimization.

Highly sensitive and quantitative HiBiT-tagged Nipah virus-like particles: A platform for rapid antibody neutralization studies

Biocontainment regulations restrict the research on NiV to BSL-4 laboratories, thus limiting the mechanistic studies related to viral entry and allied pathogenesis. Understanding the precise process of viral-particle production and host cell entry is critical for designing targeted therapies or particle-based vaccines. In this study, we have synthesized HiBiT-tagged-NiV-VLPs to ease in-vitro BSL-2 particle handling. We propose a simple yet effective approach of generating substantial amount of HiBiT-tagged NiV-VLPs in vitro by co-expressing viral structural proteins in HEK293T cells. Though homologous to parent virus, the incapacitated replication potential facilitates a BSL-2 handling of these particles. The inclusion of a highly sensitive HiBiT tag on these VLPs allows for a quick detection of viral binding and entry, as well as in assessing the efficiency of neutralizing antibodies in vitro using the NanoBiT technology. The HiBiT-tag binds in high affinity with LgBiT (Large BiT an 18 kDa fusion protein and complementary subunit of HiBiT peptide), and the resultant complex elicits high intensity luminescence in the presence of substrate. The VLPs produced were morphologically and functionally identical to the native virus, and the HiBiT-tag permitted their quick application in viral binding, entry, and antibody neutralization assays.“Thus, we report a simple setting for generating HiBiT-NiV VLPs which can be utilized in a BSL-2 laboratory, to concurrently quantify features of NiV assembly, binding and entry. This also offers an alternate-safe and effective platform for viral based antibody neutralization assays in vitro”.

An S–K Band 6-Bit Digital Step Attenuator with Ultra Low Insertion Loss and RMS Amplitude Error in 0.25 μm GaAs p-HEMT Technology

An S–K Band 6-Bit Digital Step Attenuator with Ultra Low Insertion Loss and RMS Amplitude Error in 0.25 μm GaAs p-HEMT Technology

Learning-enabled data transmission with up to 32 multiplexed orbital angular momentum channels through a commercial multi-mode fiber.

Multiplexing orbital angular momentum (OAM) modes enable high-capacity optical communication. However, the highly similar speckle patterns of adjacent OAM modes produced by strong mode coupling in common fibers prevent the utility of OAM channel demultiplexing. In this paper, we propose a machine learning-supported fractional OAM-multiplexed data transmission system to sort highly scattered data from up to 32 multiplexed OAM channels propagating through a commercial multi-mode fiber parallelly with an accuracy of >99.92%, which is the largest bit number of OAM superstates reported to date (to the best of our knowledge). Here, by learning limited samples, unseen OAM superstates during the training process can be predicted precisely, which reduces the explosive quantity of the dataset. To verify its application, both gray and colored images, encoded by the given system, have been successfully transmitted with error rates of <0.26%. Our work might provide a promising avenue for high-capacity OAM optical communication in scattering environments.

DISH: Digital image steganography using stochastic-computing with high-capacity

Stochastic computing is a relatively new approach to computing that has gained interest in recent years due to its potential for low-power and high-noise environments. It is a method of computing that uses probability to represent and manipulate data, therefore it has applications in areas such as signal processing, machine learning, and cryptography. Stochastic steganography involves hiding a message within a cover image using a statistical model. Unlike traditional steganography techniques that use deterministic algorithms to embed the message, stochastic steganography uses a probabilistic approach to hide the message in a way that makes it difficult for an adversary to detect. Due to this error robustness and large bit streams stochastic computing, they are well suited for high capacity and secure image steganography. In this paper, as per the authors’ best knowledge, image steganography using stochastic computing based on linear feedback shift register (LFSR) is proposed for the first time. In the proposed technique, the cover image is converted to stochastic representation instead of the binary one, and then a secret image is embedded in it. The resulting stego image has a high PSNR value transmitted with no visual trace of the hidden image. The final results are stego image with PSNR starting from 30 dB and a maximum payload up to 40 bits per pixel (bpp) with an effective payload up to 28 bpp. The proposed method achieves high security and high capability of the number of stored bits in each pixel. Thus, the proposed method can prove a vital solution for high capacity and secure image steganography, which can then be extended to other types of steganography.

Accuracy of routine external ventricular drain placement following a mixed reality-guided twist-drill craniostomy.

The traditional freehand placement of an external ventricular drain (EVD) relies on empirical craniometric landmarks to guide the craniostomy and subsequent passage of the EVD catheter. The diameter and trajectory of the craniostomy physically limit the possible trajectories that can be achieved during the passage of the catheter. In this study, the authors implemented a mixed reality-guided craniostomy procedure to evaluate the benefit of an optimally drilled craniostomy to the accurate placement of the catheter. Optical marker-based tracking using an OptiTrack system was used to register the brain ventricular hologram and drilling guidance for craniostomy using a HoloLens 2 mixed reality headset. A patient-specific 3D-printed skull phantom embedded with intracranial camera sensors was developed to automatically calculate the EVD accuracy for evaluation. User trials consisted of one blind and one mixed reality-assisted craniostomy followed by a routine, unguided EVD catheter placement for each of two different drill bit sizes. A total of 49 participants were included in the study (mean age 23.4 years, 59.2% female). The mean distance from the catheter target improved from 18.6 ± 12.5 mm to 12.7 ± 11.3 mm (p = 0.0008) using mixed reality guidance for trials with a large drill bit and from 19.3 ± 12.7 mm to 10.1 ± 8.4 mm with a small drill bit (p < 0.0001). Accuracy using mixed reality was improved using a smaller diameter drill bit compared with a larger bit (p = 0.039). Overall, the majority of the participants were positive about the helpfulness of mixed reality guidance and the overall mixed reality experience. Appropriate indications and use cases for the application of mixed reality guidance to neurosurgical procedures remain an area of active inquiry. While prior studies have demonstrated the benefit of mixed reality-guided catheter placement using predrilled craniostomies, the authors demonstrate that real-time quantitative and visual feedback of a mixed reality-guided craniostomy procedure can independently improve procedural accuracy and represents an important tool for trainee education and eventual clinical implementation.

Adaptive HEVC Video Steganography With High Performance Based on Attention-Net and PU Partition Modes

With the increasing popularity of digital video, video steganography has become a hot research topic in the field of covert communication and privacy protection. The existing prediction unit (PU) based video steganography often tends to result in large bit rate increase, which is also easily noticeable to the steganography analyst. To solve this problem, an adaptive steganography for HEVC video based on attention-net and PU partition modes is proposed. First, the distortion of modified PUs is analyzed from the perspective of rate distortion optimization at the group of pictures (GOP) level, and we find that modifying PU will lead to distortion accumulation and abnormal bitrate increase. Therefore, an adaptive distortion function based on the improved rate distortion cost is designed, and the embedding distortion is minimized by using Syndrome-Trellis Code (STC) steganography coding. Meanwhile, a super-resolution convolutional neural network with non-local sparse attention-net filter is proposed to replace the in-loop filter in HEVC to reconstruct the reference frame, thereby reducing the bitrate cost and improving the visual quality of stego-video. Experimental results show that the proposed algorithm can achieve superior perceptual quality and bitrate performance comparing with the sate-of-the-art works.

Video coding using closed-loop texture analysis and synthesis

The compression of video content containing high-frequency textures using the Mean Squared Error (MSE) criterion or other similar distortion measures typically leads to very large bit rate assignments to these areas. However, we assume that the exact reproduction (in an MSE sense) is subjectively not required and that other measures and coding methods can be used leading to substantially lower bit rate assignments. One such measure is a global similarity measure and we demonstrate its suitability for assessing the distortion of such textures in the context of video coding. The above-mentioned concept is adapted to a new, generic, and fully automated video coding scheme that provides a texture analyzer at the encoder and a texture synthesizer at the decoder. The texture analyzer thereby identifies the target textures, where it is assumed that the viewer perceives the semantic meaning of the displayed texture rather than the specific details therein. The texture synthesizer regenerates an approximate version of the original texture based on corresponding meta data transmitted by the encoder. The texture itself is not coded in the sense of minimizing MSE or other similar distortion measures. The new approacch is integrated into an H.264/AVC video codec and yields bit rate reductions of up to 41% when compared at the same visual quality to a reference H.264/AVC codec.

Efficient Encoding Method for Combined Codes in the MWD Telemetry System

MPPM (Multipulse Position Modulation) is a pulse code technology that is widely used in optical communication and deep space communication due to its high energy efficiency. Combination code is a variation of MPPM and is widely used in MWD (Measurement While Drilling) telemetry systems. However, whether it is MPPM or combination code, it is difficult to establish a simple mapping relationship between bit symbols and pulse symbols. Therefore, an encoding table is usually used to realize the mapping between bit symbols and pulse symbols. With an increase in bit width, the storage complexity of the encoding table increases exponentially. This is unacceptable for underground transmitters working in harsh environments. This paper maps the code symbols of MPPM to a hyper-triangular region of a high-dimensional tensor and establishes a simple lookup table and lookup algorithm to achieve low-complexity mapping from bit symbols to MPPM code symbols. At the same time, this paper also provides a method for extending from MPPM code symbols to commonly used combination code symbols in MWD, thereby providing an efficient implementation path for large bit width combination code encoding at the underground end of MWD.

SAT271 Ligand Induced GR Heterodimerization With MR In Living Cells

Abstract Disclosure: T. Sueyoshi: None. L. Perera: None. J.A. Cidlowski: None. We have established methods for monitoring heterodimer formation between GR and MR in living cells upon the addition of ligands. Two protein fragments derived from NanoBit luciferase (Small Bit peptide composed of 11 amino acids and Large Bit peptide sized 17.6 kDa) can form functional enzyme when protein-protein interaction brings these fragments close proximity. Utilizing the enzyme fragments for fusion protein partners for the hormone receptors, we have constructed expression plasmids for every combination of receptor and enzyme fragments comprising N-terminal or C-terminal fusion proteins. GR and MR fusion proteins with the luciferase fragments were expressed in HEK293 cells and the enzyme activities were determined in time course before and after the addition of ligands (dexamethasone and aldosterone). We observed robust increases of NanoBit luciferase activity in GR and MR transfected cells less than 20 min after the addition of ligands suggesting the heterodimer was formed in the time period. Similar assays detected these receptors formed homodimer after the addition of ligand for each receptor suggesting homodimer and heterodimer co-exists when appropriate ligands are in this assay system. DNA binding null mutations of GR DNA binding domain effectively abolished GR homodimers but not GR - MR heterodimers suggesting mechanistical differences between the homodimer and heterodimer formation. Based on the results only C-terminal NanoBit fusion receptors showed positive heterodimerization-induced enzyme activity, we proposed ligand binding domain 3D structure heterodimer models and found amino acid residues in helix 9, helix 10, and near C-terminus are involved in the heterodimer interaction interface. Thus, this method will be a powerful tool for analyzing molecular mechanisms of GR - MR heterodimer formation in living cells. Presentation: Saturday, June 17, 2023

An adaptive greedy heuristic for large scale airline crew pairing problems

A crew pairing represents a sequence of flight legs that constitute a crew work allocation, starting and ending at the same crew base. A complete set of crew pairings covers all flight legs in the timetable of an airline for a given planning horizon. That determines the rosters for the crew and their quality, since those pairings would potentially include layovers, deadheads and connection times which are the key factors which directly contribute to the operational crew costs. Considering that crew costs form the second largest bit in the overall operational cost, generating optimized crew pairings is a vital process for the airline companies. In this study, a score-based adaptive greedy heuristic and a genetic algorithm are presented for solving large scale instances of airline crew pairing problems. Both solution methods are applied to a set of real-world problem instances from Turkish Airlines which is one of the largest carriers in the world. The empirical results show that the proposed approaches are indeed capable of generating high quality solutions for crew pairing, even for the large scale problem instances.

Technological Prospection and Requirements of 800G Transmission Systems for Ultra-Long-Haul All-Optical Terrestrial Backbone Networks

With the standardizations of 400GE and 400G completed or near completion, the attention is now refocused to next generation techniques with larger bit rates, i.e. 800G. We can see that current research commonly aims to short-reach or metro transmission for sharing key components with 400G, while ultra-long-haul transmission (typically ≥ 1500km) based on 800G is still in unknown state. Moreover, all-optical networking with OXC and ROADM is being gradually deployed all around the world, which further increases transmission performance requirement. According to past progress, it is urgent for us to analyze and clarify the requirements of 800G transmission systems for ultra-long-haul all-optical backbone networks. This work provides the technological prospection and requirements of 800G transmission systems for ultra-long-haul all-optical backbone networks. Firstly, the field network status and basic technical requirements for 800G are analyzed. Our record real-time 10-λ×800-Gb/s sub-carrier-multiplexing 95-GBd DP PCS-64QAM transmission over 2018-km G.654.E Fiber with pure backward distributed Raman amplification shows that reusing the components of current 400G technique is not the future direction. By numerically simulating the transmission performances of non-fully-loaded and fully-loaded DWDM scenarios, symbol rate higher than 180GBd, G.654.E, and optical bandwidth ≥ 12THz are necessary.

Variable Rate Point Cloud Geometry Compression Method

With the development of 3D sensors technology, 3D point cloud is widely used in industrial scenes due to their high accuracy, which promotes the development of point cloud compression technology. Learned point cloud compression has attracted much attention for its excellent rate distortion performance. However, there is a one-to-one correspondence between the model and the compression rate in these methods. To achieve compression at different rates, a large number of models need to be trained, which increases the training time and storage space. To address this problem, a variable rate point cloud compression method is proposed, which enables the adjustment of the compression rate by the hyperparameter in a single model. To address the narrow rate range problem that occurs when the traditional rate distortion loss is jointly optimized for variable rate models, a rate expansion method based on contrastive learning is proposed to expands the bit rate range of the model. To improve the visualization effect of the reconstructed point cloud, a boundary learning method is introduced to improve the classification ability of the boundary points through boundary optimization and enhance the overall model performance. The experimental results show that the proposed method achieves variable rate compression with a large bit rate range while ensuring the model performance. The proposed method outperforms G-PCC, achieving more than 70% BD-Rate against G-PCC, and performs about, as well as the learned methods at high bit rates.

Analysis of ICONNET Fiber Optic Network Improvement in Cluster Rayon Panam at Strategic Business Unit Central Sumatra PT PLN ICON PLUS

Optical fiber is a telecommunications transmission medium that has a large bandwidth and bit rate so that it can meet the needs of today's data services with great reliability and efficiency. Optical fiber applications continue to be broad and have included seabed networks, terrestrial networks, metropolitan and regional scope networks, and small-scale networks. Optical fiber communication systems have 2 factors that affect the quality of network performance, namely internal aspects and external aspects. These internal and external aspects can degrade the performance quality of the optical fiber used and can cause attenuation and other transmission losses. As an effort to prevent sudden and significant deterioration in the quality of a network, it is necessary to try regular maintenance activities such as scheduled fiber optic cable network service quality measurements. These maintenance activities can help ensure network capacity increase decisions. One of the quality of service parameters that is often measured is transmission attenuation and received signal energy (received power). This research examines increasing the bandwidth capacity of PT PLN ICON PLUS in the Central Sumatra region during a network anomaly, namely a slow internet connection in the Rayon Panam Cluster. The sample taken from one of the customers shows the results of measuring the internet speed of 4-5 Mbps only, while the service taken is 10 Mbps. The results of checking on the up-link side to OLT Rayon Panam found that the data output was close to its capacity, which was 940,919,000 bits/sec or 0.9 Gb/sec. Increasing bandwidth capacity is done by moving the OLT port on the up-link side from the gigabit ethernet port to the tengigabit ethernet port, then replacing the SR type SFP with SFP ER and adding fiber optic attenuators so that the speed test results on the customer side have returned to their original appearance., 10 Mbps.

Ultralow-power spiking neural networks for 1024-ary orbital angular momentum shift keying free-space optical communication

The theoretical unbounded orbital angular momentum (OAM) states can be exploited as data bits in the OAM shift keying (OAM-SK) free-space optical (FSO) communications. In order to cope with the atmospheric turbulence (AT) and misalignment in practical applications, various machine learning algorithms, or neural networks (NNs), have been put forward to decode the OAM states. However, to recognize the hybrid spatial modes representing a large bit states, the massive learnable nodes, longer computation time and more training parameters are required to improve the capability of the NNs, resulting in energy efficiency burden to the hardware device. In this paper, the event-based spiking neural network (SNN) is utilized to recognize the hybrid spatial modes consisting of superposed coaxial Laguerre–Gaussian modes with l ranging from 0 to 9 and p = 0, which is termed as spiking OAM-recognition neural network (Spiking-ORNN). In comparison to the previous solution of running deep NNs on graphics processing units, the neuromorphic solution of running Spiking-ORNN on neuromorphic chips exhibits 4300× higher energy efficiency without obvious sacrifice of recognition accuracy (less than 0.5%). Moreover, we experimentally demonstrate a 10 m 1024-ary OAM-SK FSO communication for the transmission of an image with a 10 bit grey level, wherein the peak signal-to-noise ratio of the received image can exceed 41.4 dB under the AT of =10−15 m−2/3. We anticipate that our results can stimulate further researches on the utilization of the brain-like SNN chips to reduce the energy consumptions based on the artificial-intelligence-enhanced optoelectronic systems.

Long-Wavelength VCSELs: Status and Prospects

Single-mode long-wavelength (LW) vertical-cavity surface-emitting lasers (VCSELs) present an inexpensive alternative to DFB-lasers for data communication in next-generation giga data centers, where optical links with large transmission distances are required. Narrow wavelength-division multiplexing systems demand large bit rates and single longitudinal and transverse modes. Spatial division multiplexing transmission through multicore fibers using LW VCSELs is enabling still larger-scale data center networks. This review discusses the requirements for achieving high-speed modulation, as well as the state-of-the-art. The hybrid short-cavity concept allows for the realization of f3dB frequencies of 17 GHz and 22 GHz for 1300 nm and 1550 nm range VCSELs, respectively. Wafer-fusion (WF) concepts allow the realization of long-time reliable LW VCSELs with a record single-mode output power of more than 6 mW, 13 GHz 3 dB cut-off frequency, and data rates of 37 Gbit/s for non-return-to-zero (NRZ) modulation at 1550 nm.

Improved ISPP scheme for narrow threshold voltage distribution in 3-D NAND flash memory

Three-dimensional NAND flash technology exhibits a trend of increasing bit density. The narrow threshold voltage (Vth) distribution of each program state in a chip is important for increasing the number of bits in a multilevel cell (MLC) technique. An abnormal program cell (APC), which is an excessively programmed cell whose Vth overlaps with the next program state, increases the Vth distribution width (Wv). The wide Vth distribution makes it difficult to distinguish the data stored in each cell and causes data errors. In this study, an improved incremental step pulse programming (ISPP) method to narrow the Vth distribution has been proposed. As the programming step voltage (Vstep) decreases immediately before the target cells pass the nth program verify level (PVn), the difference between Vth and PVn decreases, causing a reduction in the number of APCs. Therefore, in the improved ISPP, the Vstep is selectively reduced at the target ISPP steps at which most cells are predicted to be programmed in the next ISPP step for each program state. As a result, the Wv of the improved scheme decreases compared to the conventional scheme with the minimum increase in the total number of program pulses. Larger bit density is feasible by applying improved ISPP, resulting in high-capacity NAND flash memory.