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1. SWiLoc: Fusing Smartphone Sensors and WiFi CSI for Accurate Indoor Localization

   https://doi.org/10.3390/s24196327  

   Mottakin, Khairul; Davuluri, Kiran; Allison, Mark; Song, Zheng (October 2024, Sensors)

   Dead reckoning is a promising yet often overlooked smartphone-based indoor localization technology that relies on phone-mounted sensors for counting steps and estimating walking directions, without the need for extensive sensor or landmark deployment. However, misalignment between the phone’s direction and the user’s actual movement direction can lead to unreliable direction estimates and inaccurate location tracking. To address this issue, this paper introduces SWiLoc (Smartphone and WiFi-based Localization), an enhanced direction correction system that integrates passive WiFi sensing with smartphone-based sensing to form Correction Zones. Our two-phase approach accurately measures the user’s walking directions when passing through a Correction Zone and further refines successive direction estimates outside the zones, enabling continuous and reliable tracking. In addition to direction correction, SWiLoc extends its capabilities by incorporating a localization technique that leverages corrected directions to achieve precise user localization. This extension significantly enhances the system’s applicability for high-accuracy localization tasks. Additionally, our innovative Fresnel zone-based approach, which utilizes unique hardware configurations and a fundamental geometric model, ensures accurate and robust direction estimation, even in scenarios with unreliable walking directions. We evaluate SWiLoc across two real-world environments, assessing its performance under varying conditions such as environmental changes, phone orientations, walking directions, and distances. Our comprehensive experiments demonstrate that SWiLoc achieves an average 75th percentile error of 8.89 degrees in walking direction estimation and an 80th percentile error of 1.12 m in location estimation. These figures represent reductions of 64% and 49%, respectively for direction and location estimation error, over existing state-of-the-art approaches. 

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2. 3D Janus plasmonic helical nanoapertures for polarization-encrypted data storage

   https://doi.org/10.1038/s41377-019-0156-8  

   Chen, Yang; Yang, Xiaodong; Gao, Jie (May 2019, Light: Science & Applications)

   Abstract Helical structures have attracted considerable attention due to their inherent optical chirality. Here, we report a unique type of 3D Janus plasmonic helical nanoaperture with direction-controlled polarization sensitivity, which is simply fabricated via the one-step grayscale focused ion beam milling method. Circular dichroism in transmission of as large as 0.72 is experimentally realized in the forward direction due to the spin-dependent mode coupling process inside the helical nanoaperture. However, in the backward direction, the nanoaperture acquires giant linear dichroism in transmission of up to 0.87. By encoding the Janus metasurface with the two nanoaperture enantiomers having specified rotation angles, direction-controlled polarization-encrypted data storage is demonstrated for the first time, where a binary quick-response code image is displayed in the forward direction under the circularly polarized incidence of a specified handedness, while a distinct grayscale image is revealed in the backward direction under linearly polarized illumination with a specified azimuthal angle. We envision that the proposed Janus helical nanoapertures will provide an appealing platform for a variety of applications, which will range from multifunctional polarization control, enantiomer sensing, data encryption and decryption to optical information processing. 

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3. Encoding and control of orientation to airflow by a set of Drosophila fan-shaped body neurons

   https://doi.org/10.7554/eLife.61510  

   Currier, Timothy A; Matheson, Andrew MM; Nagel, Katherine I (December 2020, eLife)

   null (Ed.)

   The insect central complex (CX) is thought to underlie goal-oriented navigation but its functional organization is not fully understood. We recorded from genetically-identified CX cell types in Drosophila and presented directional visual, olfactory, and airflow cues known to elicit orienting behavior. We found that a group of neurons targeting the ventral fan-shaped body (ventral P-FNs) are robustly tuned for airflow direction. Ventral P-FNs did not generate a ‘map’ of airflow direction. Instead, cells in each hemisphere were tuned to 45° ipsilateral, forming a pair of orthogonal bases. Imaging experiments suggest that ventral P-FNs inherit their airflow tuning from neurons that provide input from the lateral accessory lobe (LAL) to the noduli (NO). Silencing ventral P-FNs prevented flies from selecting appropriate corrective turns following changes in airflow direction. Our results identify a group of CX neurons that robustly encode airflow direction and are required for proper orientation to this stimulus. 

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4. Geometrical Relations between Slab Dip and the Location of Volcanic Arcs and Back-arc Spreading Centers

   https://doi.org/10.5281/zenodo.7636704  

   Ha, Goeun; Montési, Laurent G.; Zhu, Wenlu (January 2023, Zenodo)

   The dataset includes the measurements of individual subduction zones defined in the convergence-parallel, trench-perpendicular, and spreading-parallel direction. </p>  </p> Table S3. Location of each trench, arc, and back-arc defined in a direction parallel to the convergence, and the corresponding distance from the trench to the arc (D_TA), subarc slab depth (H), and from the trench to the back-arc spreading center (D_TB). The slab dip is measured at 50km (Dip50), 100km (Dip100), and 200km (Dip200) and averaged from 0 to 50 km (Dip050), 0 to 100km (Dip0100), 0 to 200km (Dip0200), and 50 to 200km (Dip50200). </p> Table S4. Location of each trench, arc, and back-arc defined in a direction perpendicular to the trench, and the corresponding distance from the trench to the arc (D_TA), subarc slab depth (H), and from the trench to the back-arc spreading center (D_TB). The slab dip is measured at 50km (Dip50), 100km (Dip100), and 200km (Dip200) and averaged from 0 to 50 km (Dip050), 0 to 100km (Dip0100), 0 to 200km (Dip0200), and 50 to 200km (Dip50200). </p> Table S5. Location of each trench, arc, and back-arc defined in a direction parallel to the spreading direction, and the corresponding distance from the trench to the arc (D_TA), subarc slab depth (H), and from the trench to the back-arc spreading center (D_TB). The slab dip is measured at 50km (Dip50), 100km (Dip100), and 200km (Dip200) and averaged from 0 to 50 km (Dip050), 0 to 100km (Dip0100), 0 to 200km (Dip0200), and 50 to 200km (Dip50200). </p>  </p> 

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5. Local direction change of surface gliding microtubules

   https://doi.org/10.1002/bit.26933  

   Li, Feiran; Pan, Jing; Choi, Jong_Hyun (February 2019, Biotechnology and Bioengineering)

   Abstract In vitro gliding assay, microtubule translocation by kinesin motor proteins on a surface, has been used as an engineering tool in analyte detection, molecular cargo transport, and other applications. Although controlling the moving direction is often necessary to realize these applications, current direction control methods focus largely on lithographic microfabrication of tracks or external fields on the microtubules. These methods are effective, but are relatively complicated. In addition, they cannot target particular microtubules without affecting others. In this study, we propose a facile approach that can make local direction changes for selected microtubules using a polystyrene particle as a circular motion center and a DNA double helix with streptavidin as a capture arm. The DNA arm captures a microtubule in the close proximity of the immobilized particle via biotin–streptavidin interaction and changes the moving direction ~10° on average. In contrast, no significant direction changes are observed other than random variations with streptavidin‐less DNA arms (normal distribution centered at 0°), similar to regular motility assay. The particle‐assisted local direction change scheme is compared with a flow field‐based ensemble method. The combination of flow and kinesin interactions with each microtubule exerts a force to change the direction, ultimately aligning it to the flow field, regardless of its initial direction. A simple model based on the force balance predicts the time needed for such an alignment. Overall, the particle‐based local scheme is distinct and different from ensemble methods such as crossflow that changes directions of all microtubules in the field, thus offering unique utility in engineering applications. 

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