Link between T-Linear Resistivity and Quantum Criticality in Ambipolar Black Phosphorus.

The interplay between strong Coulomb interactions and kinetic energy leads to intricate many-body competing ground states owing to quantum fluctuations in 2D electron and hole gases. However, the simultaneous observation of quantum critical phenomena in both electron and hole regimes remains elusive. Here, we utilize anisotropic black phosphorus (BP) to show density-driven metal-insulator transition with a critical conductance ∼e2/h which highlights the significant role of quantum fluctuations in both hole and electron regimes. We observe a T-linear resistivity from the deep metallic phase to the metal-insulator boundary at moderate temperatures, while it turns to Fermi liquid behavior in the deep metallic phase at low temperatures in both regimes. An analysis of the resistivity suggests that disorder-dominated transport leads to T-linear behavior in the hole regime, while in the electron regime, the T-linear resistivity results from strong Coulomb interactions, suggestive of strange-metal behavior. Successful scaling collapse of the resistivity in the T-linear region demonstrates the link between quantum criticality and the T-linear resistivity in both regimes. Our study provides compelling evidence that ambipolar BP could serve as an exciting testbed for investigating exotic states and quantum critical phenomena in hole and electron regimes of 2D semiconductors.

Percolation-Based Metal-Insulator Transition in Black Phosphorus Field Effect Transistors.

The existence of a novel phenomenon, such as the metal-insulator transition (MIT) in two-dimensional (2D) systems, affords emerging functional properties that provide new aspects for future electronics and optoelectronics. Here, we report the observation of the MIT in black phosphorus field effect transistors by tuning the carrier density (n) controlled by back-gate bias. We find that the conductivity follows an n dependence as σ(n) ∝ nα with α ∼ 1, which indicates the presence of screened Coulomb impurity scattering at high carrier densities in the temperature range of 10-300 K. As n decreases, the screened Coulomb impurity scattering breaks down, developing strong charge density inhomogeneity leading to a percolation-based transition at the critical carrier density (nC). At low carrier densities (n < nC), the system is in the insulating regime, which is expressed by Mott variable range hopping that demonstrates the role of disorder in the system. In addition, the extracted average values of critical exponent δ are ∼1.29 ± 0.01 and ∼1.14 ± 0.01 for devices A and B, respectively, consistent with the 2D percolation exponent of 4/3, confirming the 2D percolation-based MIT in BP devices. Our findings strongly suggest that the 2D MIT observed in BP is a classical percolation-based transition caused by charge inhomogeneity induced by screened Coulomb charge impurity scattering around a transition point controlled by n through back-gate bias.

FPGA Implementation of the Chirp-Scaling Algorithm for Real-Time Synthetic Aperture Radar Imaging.

Synthetic aperture radar (SAR), which can generate images of regions or objects, is an important research area of radar. The chirp scaling algorithm (CSA) is a representative SAR imaging algorithm. The CSA has a simple structure comprising phase compensation and fast Fourier transform (FFT) operations by replacing interpolation for range cell migration correction (RCMC) with phase compensation. However, real-time processing still requires many computations and a long execution time. Therefore, it is necessary to develop a hardware accelerator to improve the speed of algorithm processing. In addition, the demand for a small SAR system that can be mounted on a small aircraft or drone and that satisfies the constraints of area and power consumption is increasing. In this study, we proposed a CSA-based SAR processor that supports FFT and phase compensation operations and presents field-programmable gate array (FPGA)-based implementation results. We also proposed a modified CSA flow that simplifies the traditional CSA flow by changing the order in which the transpose operation occurs. Therefore, the proposed CSA-based SAR processor was designed to be suitable for modified CSA flow. We designed the multiplier for FFT to be shared for phase compensation, thereby achieving area efficiency and simplifying the data flow. The proposed CSA-based SAR processor was implemented on a Xilinx UltraScale+ MPSoC FPGA device and designed using Verilog-HDL. After comparing the execution times of the proposed SAR processor and the ARM cortex-A53 microprocessor, we observed a 136.2-fold increase in speed for the 4096 × 4096-pixel image.

Cathelicidin-related antimicrobial peptide mediates skeletal muscle degeneration caused by injury and Duchenne muscular dystrophy in mice.

BACKGROUND: Cathelicidin, an antimicrobial peptide, plays a key role in regulating bacterial killing and innate immunity; however, its role in skeletal muscle function is unknown. We investigated the potential role of cathelicidin in skeletal muscle pathology resulting from acute injury and Duchenne muscular dystrophy (DMD) in mice. METHODS: Expression changes and muscular localization of mouse cathelicidin-related antimicrobial peptide (Cramp) were examined in the skeletal muscle of normal mice treated with chemicals (cardiotoxin and BaCl2 ) or in dystrophic muscle of DMD mouse models (mdx, mdx/Utrn+/- and mdx/Utrn-/- ). Cramp penetration into myofibres and effects on muscle damage were studied by treating synthetic peptides to mouse skeletal muscles or C2C12 myotubes. Cramp knockout (KO) mice and mdx/Utrn/Cramp KO lines were used to determine whether Cramp mediates muscle degeneration. Muscle pathophysiology was assessed by histological methods, serum analysis, grip strength and lifespan. Molecular factors targeted by Cramp were identified by the pull-down assay and proteomic analysis. RESULTS: In response to acute muscle injury, Cramp was activated in muscle-infiltrating neutrophils and internalized into myofibres. Cramp treatments of mouse skeletal muscles or C2C12 myotubes resulted in muscle degeneration and myotube damage, respectively. Genetic ablation of Cramp reduced neutrophil infiltration and ameliorated muscle pathology, such as fibre size (P < 0.001; n = 6) and fibrofatty infiltration (P < 0.05). Genetic reduction of Cramp in mdx/Utrn+/- mice not only attenuated muscle damage (35%, P < 0.05; n = 9-10), myonecrosis (53%, P < 0.05), inflammation (37-65%, P < 0.01) and fibrosis (14%, P < 0.05) but also restored muscle fibre size (14%, P < 0.05) and muscle force (18%, P < 0.05). Reducing Cramp levels led to a 63% (male, P < 0.05; n = 10-14) and a 124% (female, P < 0.001; n = 20) increase in the lifespan of mdx/Utrn-/- mice. Proteomic and mechanistic studies revealed that Cramp cross-talks with Ca2+ signalling in skeletal muscle through sarcoplasmic/endoplasmic reticulum Ca2+ -ATPase1 (SERCA1). Cramp binds and inactivates SERCA1, leading to the activation of Ca2+ -dependent calpain proteases that exacerbate DMD progression. CONCLUSIONS: These findings identify Cramp as an immune cell-derived regulator of skeletal muscle degeneration and provide a potential therapeutic target for DMD.

Selective Electron Beam Patterning of Oxygen-Doped WSe2 for Seamless Lateral Junction Transistors.

Surface charge transfer doping (SCTD) using oxygen plasma to form a p-type dopant oxide layer on transition metal dichalcogenide (TMDs) is a promising doping technique for 2D TMDs field-effect transistors (FETs). However, patternability of SCTD is a key challenge to effectively switch FETs. Herein, a simple method to selectively pattern degenerately p-type (p+ )-doped WSe2 FETs via electron beam (e-beam) irradiation is reported. The effect of the selective e-beam irradiation is confirmed by the gate-tunable optical responses of seamless lateral p+ -p diodes. The OFF state of the devices by inducing trapped charges via selective e-beam irradiation onto a desired channel area in p+ -doped WSe2 , which is in sharp contrast to globally p+ -doped WSe2 FETs, is realized. Selective e-beam irradiation of the PMMA-passivated p+ -WSe2 enables accurate control of the threshold voltage (Vth ) of WSe2 devices by varying the pattern size and e-beam dose, while preserving the low contact resistance. By utilizing hBN as the gate dielectric, high-performance WSe2 p-FETs with a saturation current of -280 µA µm-1 and on/off ratio of 109 are achieved. This study's technique demonstrates a facile approach to obtain high-performance TMD p-FETs by e-beam irradiation, enabling efficient switching and patternability toward various junction devices.

Architecture Exploration of a Backprojection Algorithm for Real-Time Video SAR.

This paper explores novel architectures for fast backprojection based video synthetic aperture radar (BP-VISAR) with multiple GPUs. The video SAR frame rate is analyzed for non-overlapped and overlapped aperture modes. For the parallelization of the backprojection process, a processing data unit is defined as the phase history data or range profile data from partial synthetic-apertures divided from the full resolution target data. Considering whether full-aperture processing is performed and range compression or backprojection are parallelized on a GPU basis, we propose six distinct architectures, each having a single-stream pipeline with a single GPU. The performance of these architectures is evaluated in both non-overlapped and overlapped modes. The efficiency of the BP-VISAR architecture with sub-aperture processing in the overlapped mode is accelerated further by filling the processing gap from the idling GPU resources with multi-stream based backprojection on multiple GPUs. The frame rate of the proposed BP-VISAR architecture with sub-aperture processing is scalable with the number of GPU devices for large pixel resolution. It can generate 4096 × 4096 video SAR frames of 0.5 m cross-range resolution in 23.0 Hz on a single GPU and 73.5 Hz on quad GPUs.

Compressive Sensing-Based SAR Image Reconstruction from Sparse Radar Sensor Data Acquisition in Automotive FMCW Radar System.

In this paper, we propose a method for reconstructing synthetic aperture radar (SAR) images by applying a compressive sensing (CS) technique to sparsely acquired radar sensor data. In general, SAR image reconstruction algorithms require radar sensor data acquired at regular spatial intervals. However, when the speed of the radar-equipped platform is not constant, it is difficult to consistently perform regular data acquisitions. Therefore, we used the CS-based signal recovery method to efficiently reconstruct SAR images even when regular data acquisition was not performed. In the proposed method, we used the l1-norm minimization to overcome the non-uniform data acquisition problem, which replaced the Fourier transform and inverse Fourier transform in the conventional SAR image reconstruction method. In addition, to reduce the phase distortion of the recovered signal, the proposed method was applied to each of the in-phase and quadrature components of the acquired radar sensor data. To evaluate the performance of the proposed method, we conducted experiments using an automotive frequency-modulated continuous wave radar sensor. Then, the quality of the SAR image reconstructed with data acquired at regular intervals was compared with the quality of images reconstructed with data acquired at non-uniform intervals. Using the proposed method, even if only 70% of the regularly acquired radar sensor data was used, a SAR image having a correlation of 0.83 could be reconstructed.

Region-Based Static Video Stitching for Reduction of Parallax Distortion.

In this paper, we propose a semantic segmentation-based static video stitching method to reduce parallax and misalignment distortion for sports stadium scenes with dynamic foreground objects. First, video frame pairs for stitching are divided into segments of different classes through semantic segmentation. Region-based stitching is performed on matched segment pairs, assuming that segments of the same semantic class are on the same plane. Second, to prevent degradation of the stitching quality of plain or noisy videos, the homography for each matched segment pair is estimated using the temporally consistent feature points. Finally, the stitched video frame is synthesized by stacking the stitched matched segment pairs and the foreground segments to the reference frame plane by descending order of the area. The performance of the proposed method is evaluated by comparing the subjective quality, geometric distortion, and pixel distortion of video sequences stitched using the proposed and conventional methods. The proposed method is shown to reduce parallax and misalignment distortion in segments with plain texture or large parallax, and significantly improve geometric distortion and pixel distortion compared to conventional methods.

Intra-Articular Administration of Cramp into Mouse Knee Joint Exacerbates Experimental Osteoarthritis Progression.

Osteoarthritis (OA) is the most common type of arthritis and is associated with wear and tear, aging, and inflammation. Previous studies revealed that several antimicrobial peptides are up-regulated in the knee synovium of patients with OA or rheumatoid arthritis. Here, we investigated the functional effects of cathelicidin-related antimicrobial peptide (Cramp) on OA pathogenesis. We found that Cramp is highly induced by IL-1ß via the NF-κB signaling pathway in mouse primary chondrocytes. Elevated Cramp was also detected in the cartilage and synovium of mice suffering from OA cartilage destruction. The treatment of chondrocytes with Cramp stimulated the expression of catabolic factors, and the knockdown of Cramp by small interfering RNA reduced chondrocyte catabolism mediated by IL-1ß. Moreover, intra-articular injection of Cramp into mouse knee joints at a low dose accelerated traumatic OA progression. At high doses, Cramp affected meniscal ossification and tears, leading to cartilage degeneration. These findings demonstrate that Cramp is associated with OA pathophysiology.

Multi-Frame Based Homography Estimation for Video Stitching in Static Camera Environments.

In this paper, a multi-frame based homography estimation method is proposed for video stitching in static camera environments. A homography that is robust against spatio-temporally induced noise can be estimated by intervals, using feature points extracted during a predetermined time interval. The feature point with the largest blob response in each quantized location bin, a representative feature point, is used for matching a pair of video sequences. After matching representative feature points from each camera, the homography for the interval is estimated by random sample consensus (RANSAC) on the matched representative feature points, with their chances of being sampled proportional to their numbers of occurrences in the interval. The performance of the proposed method is compared with that of the per-frame method by investigating alignment distortion and stitching scores for daytime and noisy video sequence pairs. It is shown that alignment distortion in overlapping regions is reduced and the stitching score is improved by the proposed method. The proposed method can be used for panoramic video stitching with static video cameras and for panoramic image stitching with less alignment distortion.

The device level modulation of carrier transport in a 2D WSe2 field effect transistor via a plasma treatment.

Tungsten diselenide (WSe2) has received significant attention because it shows the pristine ambipolar property arising from the Fermi level located near the midgap and can be converted to uni-polar form. In this study, we observe the formation of tungsten oxide (WOx) on the WSe2 surface after oxygen plasma treatment and show that the p-type WOx dopes WSe2. In our devices that underwent plasma treatment, it was interesting to find a strong correlation between the changes in the work function of WSe2 and a gold electrode, and the channel and contact resistances. The channel resistance changes very sensitively at a rate of 64 meV per dec with the increase in the WSe2 channel work function, which is close to the thermal limit; this indicates the defect-free oxidized WSe2 channel. The carrier transport in the oxidized WSe2 FET is shown to change to a high performance p-type device with greatly reduced channel and contact resistances with the increase in the plasma oxidation time.

A Fermi-Level-Pinning-Free 1D Electrical Contact at the Intrinsic 2D MoS2 -Metal Junction.

Currently 2D crystals are being studied intensively for use in future nanoelectronics, as conventional semiconductor devices face challenges in high power consumption and short channel effects when scaled to the quantum limit. Toward this end, achieving barrier-free contact to 2D semiconductors has emerged as a major roadblock. In conventional contacts to bulk metals, the 2D semiconductor Fermi levels become pinned inside the bandgap, deviating from the ideal Schottky-Mott rule and resulting in significant suppression of carrier transport in the device. Here, MoS2 polarity control is realized without extrinsic doping by employing a 1D elemental metal contact scheme. The use of high-work-function palladium (Pd) or gold (Au) enables a high-quality p-type dominant contact to intrinsic MoS2 , realizing Fermi level depinning. Field-effect transistors (FETs) with Pd edge contact and Au edge contact show high performance with the highest hole mobility reaching 330 and 432 cm2 V-1 s-1 at 300 K, respectively. The ideal Fermi level alignment allows creation of p- and n-type FETs on the same intrinsic MoS2 flake using Pd and low-work-function molybdenum (Mo) contacts, respectively. This device acts as an efficient inverter, a basic building block for semiconductor integrated circuits, with gain reaching 15 at VD = 5 V.

Comparative Study on the Epidemiological Trends and Aspects of Murine Typhus in Korea in the Last Decade (2006-2015).

INTRODUCTION: In this study, we undertook a retrospective analysis of the epidemiological aspects and risk factors of murine typhus (MT) in Korea in the last decade (2006-2015). MATERIALS AND METHODS: MT infections in Korea using a total of 411 cases obtained from the Diseases Web Statistical System of the Korea Center for Disease Control and Prevention. RESULTS: In a total of 411 MT infection cases, the cumulative incidence rate was 0.08/100,000 populations. Men were slightly more infected by MT as compared to women (51.3% vs. 48.7%), and a higher incidence of MT was observed in people aged over 40 years (93.4%; P < 0.01). The seasonal pattern of outbreaks revealed that most infections occurred from October to November (69.1% of the total cases) (P < 0.01). Significantly more outbreaks occurred in the southern part (53.5%) of the Korean peninsula as compared to its northern (33.3%) and central (10.7%) parts, as well as the Jeju Island (1.0%) (P < 0.01). In addition, the number of MT infections was significantly higher in rural and sea-village (87.6%) than in urban areas (12.4%; P < 0.01). CONCLUSION: In conclusion, the rapid reemergence of MT outbreaks can be minimized through health education, and a strong enforcement of control measures against rats and their ectoparasites could markedly reduce the transmission of this infection to humans in high-risk areas.

International Travel and Exotic Dengue Fever in South Korea from 2006 to 2015.

We analyzed reported dengue fever (DF) cases and DF-relevant characteristics in South Korea from 2006 to 2015. A total of 1,260 DF notifications were obtained during the study period that were presumably introduced from endemic foreign countries. The nationwide cumulative incidence rate (CIR) of DF was 0.25 per 100,000 population; CIR of DF among overseas travelers was 0.93. CIRs of overseas male and female travelers were 1.13 and 0.87, respectively. CIR of overseas travelers aged 20-39 years was the highest. More men (61.9%) were infected with the dengue virus than women (38.1%, P<0.01). Individuals aged 20-39 years were most infected than those of other ages (58.4%, P<0.01). About a third of reported DF cases occurred between June and November. Most of the imported DF cases were associated with traveling in Southeast Asia (86.1%). The incidence of DF was highly correlated with the total number of overseas travelers (Pearson correlation r=0.842, P<0.01). The number of reported patients with DF has been increasing in the last decade, and DF is associated with international travel. To prevent dengue virus infections, greater attention should be paid to individuals who are planning to travel to Southeast Asia.

Modulation of Quantum Tunneling via a Vertical Two-Dimensional Black Phosphorus and Molybdenum Disulfide p-n Junction.

Diverse diode characteristics were observed in two-dimensional (2D) black phosphorus (BP) and molybdenum disulfide (MoS2) heterojunctions. The characteristics of a backward rectifying diode, a Zener diode, and a forward rectifying diode were obtained from the heterojunction through thickness modulation of the BP flake or back gate modulation. Moreover, a tunnel diode with a precursor to negative differential resistance can be realized by applying dual gating with a solid polymer electrolyte layer as a top gate dielectric material. Interestingly, a steep subthreshold swing of 55 mV/dec was achieved in a top-gated 2D BP-MoS2 junction. Our simple device architecture and chemical doping-free processing guaranteed the device quality. This work helps us understand the fundamentals of tunneling in 2D semiconductor heterostructures and shows great potential in future applications in integrated low-power circuits.

A Comparative Study of the Trends of Imported Dengue Cases in Korea and Japan 2011 - 2015.

BACKGROUND: Dengue is a mosquito-borne febrile disease that represents a major public health problem in tropical and subtropical areas. Even though Korea and Japan are not the regions where dengue is epidemic, there have been many imported cases in both countries, and in increasing numbers. A better understanding of the characteristics of the prevalence of dengue and the recent trends in these neighboring countries may provide information to promote improvement and control strategies for both. The present study investigated the epidemiological status of imported dengue cases in Korea and Japan between 2011 and 2015, and compared their characteristics. METHODS: We analyzed the annual transition of prevalence, geographic origin of dengue infection, and seasonal distribution of occurrence. The raw data on dengue cases in Korea were obtained from the Korea Center for Disease Control and Prevention infectious diseases surveillance website and Korean Statistical Information Service website. Data on dengue cases in Japan were obtained from the National Institute of Infectious Diseases, Japan's Infectious Disease Surveillance Center website. RESULTS: There were 893 reported cases in Korea and 1,054 in Japan between 2011 and 2015. Cumulative incidence per 100,000 overseas travelers from Japan did not substantially differ from that for Korea (1.22 vs. 1.16, respectively), despite Japan's population being roughly 2.5 times larger. These results suggest Koreans engage in overseas travel more than Japanese. For Korea and Japan, Southeast Asia was the region accounting for the most cases of infection (89.4% vs. 75.4%, respectively). Notably, the Philippines and Indonesia were, respectively, the leading origin countries for Korean (38.1%) and Japanese (23.3%) cases. Seasonal distribution shows August and September were the months in which the largest number of cases occurred in Korea and Japan, respectively. These differences evidently derive from characteristics of travel destinations and timing of holidays. CONCLUSION: Based on the recent increasing trend in imported dengue cases in both countries, a more rigorous information system that can effectively provide warning of dengue risk and means of prevention for travelers headed to at-risk areas is urgently needed in both countries.

Shadow Detection Based on Regions of Light Sources for Object Extraction in Nighttime Video.

Intelligent video surveillance systems detect pre-configured surveillance events through background modeling, foreground and object extraction, object tracking, and event detection. Shadow regions inside video frames sometimes appear as foreground objects, interfere with ensuing processes, and finally degrade the event detection performance of the systems. Conventional studies have mostly used intensity, color, texture, and geometric information to perform shadow detection in daytime video, but these methods lack the capability of removing shadows in nighttime video. In this paper, a novel shadow detection algorithm for nighttime video is proposed; this algorithm partitions each foreground object based on the object's vertical histogram and screens out shadow objects by validating their orientations heading toward regions of light sources. From the experimental results, it can be seen that the proposed algorithm shows more than 93.8% shadow removal and 89.9% object extraction rates for nighttime video sequences, and the algorithm outperforms conventional shadow removal algorithms designed for daytime videos.

A Comparative Study of the Epidemiological Aspects of Legionnaires' Disease: Outbreaks in Korea and Japan, 2010 - 2014.

BACKGROUND: In the present study, we compared the epidemiological aspects of Legionnaire' disease (LD) outbreaks in Korea and Japan by analyzing the current state from 2010 to 2014. METHODS: The following factors were analyzed: nationwide cumulative incidence rate (CIR) per 100,000 populations and case-fatality rate in percentage, epidemiological aspects (i.e., case related to gender), male to female morbidity ratio (MFMR), age, seasonality and habitat distribution of LD cases. RESULTS: In total, there were 134 cases of LD with the CIR of 0.05 per 100,000 populations in Korea from 2010 to 2014. During the same period in Japan, there were 4,840 cases of LD with a CIR of 0.76 per 100,000 populations. The CIR in Japan was significantly higher than that in Korea. However, the case-fatality rates were at similar levels (3.0% vs. 5.9%). Moreover, LD affects both sexes differently, accounting for 2.05 and 4.41 of MFMR in Korea and Japan, respectively. In both countries, the incidence mainly occurred among people aged 40 years or older, and peaked in summer (37.3% vs. 33.7% of total cases). Significant differences were observed in the incidence of LD cases between the capital city and county areas in both two countries. These differences in LD risk factors reflect the different influences of reservoir/host with natural or artificial aquatic environments. CONCLUSION: This study provides a quantitative analysis of the epidemiological aspects and risk factors of LD outbreaks in Korea and Japan. We hope this study would be helpful for providing insight on effective future strategies to reduce LD outbreaks.

A Comparative Study of the Epidemiology of Human Leptospirosis in Korea and Japan between 2006 and 2012.

We undertook a comparative analysis of the epidemiology of reported human leptospirosis (HL) cases in Korea and Japan. Between 2006 and 2012, the cumulative incidence of HL in Korea was higher than that in Japan (1.26 vs. 0.14 per 100,000 population, respectively), and the total reported cases were 632 and 196, respectively. Significantly more men were infected than women in both Korea (63.0% men, P < 0.01) and Japan (87.8% men, P < 0.01). In both countries, the incidence was highest among those aged 40 years and older (60%), and peaked in autumn (78.5% cases in Korea, and 46.9% cases in Japan). However, Japan exhibited a significantly higher proportion of male cases, a younger age distribution, and less prominent seasonality. A significant difference was observed in the incidence of HL between the capital city and rural areas in Korea, but not in Japan. The differences in agricultural and forestry practices, and the efficacy or wastewater treatment infrastructure might influence the incidence level in rural areas in both countries. The differences between the 2 countries might be because of their unique geographical characteristics and variations in their levels of industrialization.

Step Detection Robust against the Dynamics of Smartphones.

A novel algorithm is proposed for robust step detection irrespective of step mode and device pose in smartphone usage environments. The dynamics of smartphones are decoupled into a peak-valley relationship with adaptive magnitude and temporal thresholds. For extracted peaks and valleys in the magnitude of acceleration, a step is defined as consisting of a peak and its adjacent valley. Adaptive magnitude thresholds consisting of step average and step deviation are applied to suppress pseudo peaks or valleys that mostly occur during the transition among step modes or device poses. Adaptive temporal thresholds are applied to time intervals between peaks or valleys to consider the time-varying pace of human walking or running for the correct selection of peaks or valleys. From the experimental results, it can be seen that the proposed step detection algorithm shows more than 98.6% average accuracy for any combination of step mode and device pose and outperforms state-of-the-art algorithms.