13,239 research outputs found
Securing Communications with Friendly Unmanned Aerial Vehicle Jammers
No full textIn this paper, we analyze the impact of a friendly unmanned aerial vehicle (UAV) jammer on UAV communications in the presence of multiple eavesdroppers. We first present channel components determined by the line-of-sight (LoS) probability between the friendly UAV jammer and the ground device, and introduce different channel fadings for LoS and non-line-of-sight (NLoS) links. We then derive the secrecy transmission probability satisfying both constraints of legitimate and wiretap channels. We also analyze the secrecy transmission probability in the presence of randomly distributed multiple friendly UAV jammers. Finally, we show the existence of the optimal UAV jammer location, and the impact of the density of eavesdroppers, the transmission power of the UAV jammer, and the density of UAV jammers on the optimal location. IEEE1
DiTTO: A Distance Adaptive Over 100-mW Wireless Power Transfer System With 1.695-Mb/s Uplink Telemetry and a Shared Inductor Two-Output Regulating Rectification
No full textThis article presents a wireless power transfer (WPT) system that incorporates a seamless uplink data telemetry and a simultaneous shared inductor dual-output (SIDO) regulating rectification (RR) under distance variation over a single WPT link. The proposed double charging keying (DCK) uplink data modulation method assisted by a dynamic zoom control breaks the trade-off between power delivery to the load (PDL) and uplink data such that the high data-rate uplink data telemetry no longer limits the amount of PDLs. Furthermore, DCK alleviates the design difficulty in simultaneous uplink data telemetry and RR. The dynamic ZOOM-based digital control algorithm is employed to ensure reliable uplink data telemetry and rapid transient response of SIDO-RR with two Delta Sigma -loops under distance variations. This work achieves 1.695-Mb/s uplink data rate while delivering up to 108 mW to two independent loads over 10-42-mm single-link distance. The chip fabricated in standard 65-nm CMOS occupies 0.2-mm(2 )active area and its performance is validated through in vivo experiments.
Author Correction: Evaluation of skin cancer resection guide using hyper‑realistic in‑vitro phantom fabricated by 3D printing
No full textThe original version of this Article contained an error in the spelling of the author Taehun Kim which was incorrectly given as Teahun Kim. The original Article has been corrected
Table Recognition and Comparison Technology with AI in Technical Specifications for Equipment Purchasing Order
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Stretchable Electrodes Based on Over‐Layered Liquid Metal Networks
No full textLiquid metals are attractive materials for stretchable electronics owing to their high electrical conductivity and near-zero Young's modulus. However, the high surface tension of liquid metals makes it difficult to form films. A novel stretchable film is proposed based on an over-layered liquid-metal network. An intentionally oxidized interfacial layer helps to construct uninterrupted indium and gallium nanoclusters and produces additional electrical pathways between the two metal networks under mechanical deformation. The films exhibit gigantic negative piezoresistivity (G-NPR), which decreased the resistance up to 85% during the first 50% stretching. This G-NPR property is due to the rupture of the metal oxides, which allows the formation of liquid eutectic gallium-indium (EGaIn) and the connection of the over-layered networks to build new electrical paths. The electrodes exhibiting G-NPR are complementarily combined with conventional electrodes to amplify their performance or achieve some unique operations.
A Study about Chuimsae by Han Seongjun: - Focused on Columbia -
No full text판소리 고법에는 추임새가 동반된다. 한성준(1874~1941)은 근대시대 고수로서 왕성을 한 고 수인데, 고법(drumming pattern)의 연구와 함께 추임새의 연구도 수반되어야 한다. 본고에서는 이를 Columbia 의 진양조 장단을 중심으로 살펴보고 한성준의 추임새가 나타나는 박의 위치를 살펴보았다. 또, 추임새말의 종류 및 출현빈도, 그리고 추임새 성음의 양상 등을 살펴보았 다. 그 결과로 한성준의 추임새는 대개 진양조 장단 제 6박 위치에 나타났으며, 좋다라는 추임새 를 가장 많이 사용한 것으로 나타났다. 또 그의 추임새는 1~10도의 다양한 종류의 도약으로 표현 되었다. 요컨대 한성준의 추임새는 음악적인 형식이나 틀에 따라 정해진 규칙이 있지는 않았고 그 이유를 고수의 즉흥적인 판단에 기인한 것으로 보았다While Pansori singer sings a melody, a drummers drumming is to be accompanied. When it happens, drummer also calls out a cheering sound, called Chuimsae. Han Seongjun(1874~1941) is considered to be one of the best Pansori drummer in the early 20th century. Not only his drumming pattern, but also his Chuimsae are also needed to be examined for more understandings of earlier Pansori drumming. Through the study, it is found that Han more likely calls out a Chuimsae on the 6th beat of Jinyangjo Jangdan, and Jota is known to be his favorite Chuimsae word. However, he didnt used preset rules, but only did it by musical improvisational situations
Neo-GNNs: Neighborhood Overlap-aware Graph Neural Networks for Link Prediction
No full textGraph Neural Networks (GNNs) have been widely applied to various fields for learning over graph-structured data. They have shown significant improvements over traditional heuristic methods in various tasks such as node classification and graph classification. However, since GNNs heavily rely on smoothed node features rather than graph structure, they often show poor performance than simple heuristic methods in link prediction where the structural information, e.g., overlapped neighborhoods, degrees, and shortest paths, is crucial. To address this limitation, we propose Neighborhood Overlap-aware Graph Neural Networks (Neo-GNNs) that learn useful structural features from an adjacency matrix and estimate overlapped neighborhoods for link prediction. Our Neo-GNNs generalize neighborhood overlap-based heuristic methods and handle overlapped multi-hop neighborhoods. Our extensive experiments on Open Graph Benchmark datasets (OGB) demonstrate that Neo-GNNs consistently achieve state-of-the-art performance in link prediction
Effects of Cervical Extension on Deformation of Intervertebral Disk and Migration of Nucleus Pulposus
No full textBackground: We theorized that active cervical extension should influence the position of the nucleus pulposus (NP) within the intervertebral disk (IVD) in the sagittal plane. Although several studies on the lumbar IVD have been conducted, there are no quantitative data for in vivo positional changes of the NP in the cervical IVD. Objective: To evaluate the influence and mechanism of cervical extension on the deformation and migration of IVD and NP in the sagittal plane and understand underlying mechanisms of the extension maneuver. Design: Asymptomatic subjects underwent magnetic resonance imaging while supine with their cervical spines in neutral and extended positions. Setting: Academic medical center. Participants: Ten young, healthy male participants (age range 19-30 years; mean 22.4 +/- 1.64 years). Methods: T2-weighted sagittal images from C3-C4 to C6-C7 of subjects in both neutral and extension positions were analyzed. Main Outcome Measurements: Deformation of IVD and positional change of NP were quantified and compared between neutral and extension positions. Intersegmental angles between vertebrae, horizontal positions of anterior and posterior IVD and NP margins, IVD outer and inner heights, and sagittal morphology of NP were quantified and compared between the neutral and extension positions. Correlations between the measured parameters and segmental extension angle were also investigated. Results: Anterior and posterior IVD margins moved posteriorly with respect to the vertebral body in extension. Both NP margins remained unchanged relative to the vertebral body but moved anteriorly with respect to the IVD. IVD outer and inner heights in the anterior region increased in extension, and morphological changes of the NP were less noticeable when compared with its relative migration within the IVD. Most of the intradiskal changes were linearly correlated with the segmental extension angle. Conclusions: Cervical extension induces anterior migration of the NP away from the posterior disk margin and may have a clinical effect on diskogenic neck pain resulting from internal disk disruption.
Graph transformer networks
No full textGraph neural networks (GNNs) have been widely used in representation learning on graphs and achieved state-of-the-art performance in tasks such as node classification and link prediction. However, most existing GNNs are designed to learn node representations on the fixed and homogeneous graphs. The limitations especially become problematic when learning representations on a misspecified graph or a heterogeneous graph that consists of various types of nodes and edges. In this paper, we propose Graph Transformer Networks (GTNs) that are capable of generating new graph structures, which involve identifying useful connections between unconnected nodes on the original graph, while learning effective node representation on the new graphs in an end-to-end fashion. Graph Transformer layer, a core layer of GTNs, learns a soft selection of edge types and composite relations for generating useful multi-hop connections so-called meta-paths. Our experiments show that GTNs learn new graph structures, based on data and tasks without domain knowledge, and yield powerful node representation via convolution on the new graphs. Without domain-specific graph preprocessing, GTNs achieved the best performance in all three benchmark node classification tasks against the state-of-the-art methods that require pre-defined meta-paths from domain knowledge
Transformable underwater docking mechanism based on origami-inspired deployable and bistable structures
No full textThe increasing deployment of autonomous systems, such as autonomous underwater vehicles (AUVs), highlights critical need for robust and efficient recovery mechanisms. A significant challenge in extended autonomous operations is the limited onboard battery capacity, which necessitates reliable docking solutions. This paper presents a transformable underwater docking mechanism based on origami-inspired deployable and bistable structures, which can be mounted on a submarine. The proposed docking station system is divided into two components, which are the deployable funnel, and the landing station, respectively. The deployable funnel and landing station employe the Sarrus linkage and bistable structure, respectively. Additionally, the applied structures help reduce the burden on system control, enabling the use of a minimal number of actuators. The grasping forces of both components are analyzed, and the structural stability is simulated. The performance of the proposed mechanism is verified by conducting five underwater docking experiments in a circulation water tunnel with a free-stream velocity of 0.6 m/s.
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