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FPCA: Parasitic coding Authentication for UAVs by FM Signals

IEEE-ACM TRANSACTIONS ON NETWORKING 2024年第6期32卷 4570-4584页

作者： Zhu, Shaopeng Zheng, Xiaolong Liu, Liang Ma, Huadong Beijing Univ Posts & Telecommun Sch Comp Sci State Key Lab Networking & Switching Technol Beijing 100088 Peoples R China

De-authentication attack is one of the major threats to Unmanned Aerial Vehicle (UAV) communication, in which the attacker continuously sends de-authentication frames to disconnect the UAV communication link. Existing defense methods are based on authentication by digital passwords or physical channel features. But they suffer from replay attacks or cannot adapt to the UAV mobility. In this paper, instead of enhancing the in-channel authentication, we leverage the ambient broadcasting signal to establish a low-cost additional channel for authentication. Different from methods using another dedicated secure communication channel to perform an independent authentication, we use the ambient FM radio broadcasting channel and couple the two channels by encoding parasitic bits on the host signals of the broadcasting channel, which is called parasitic coding. To further enhance the security, we propose the FM-based Parasitic coding Authentication (FPCA) that leverages elaborate host signal processing and vector coding to ensure that the attacker cannot decode our authentication even knowing the FM receiving frequency. We implement FPCA on the embedded UAV platform. The extensive experiments show that FPCA can resist replay attacks and brute force searching, achieving reliable continuous authentication for UAVs.

关键词： Authentication Autonomous aerial vehicles Encoding Frequency modulation Reliability Receivers Security Broadcasting Wireless communication vectors UAV de-authentication attack authentication FM signal vector coding

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Joint Coordination and Stiffness During Landing in Individuals With Chronic Ankle Instability

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JOURNAL OF APPLIED BIOMECHANICS 2021年第2期37卷 156-162页

作者： Li, Yumeng Ko, Jupil Walker, Marika A. Brown, Cathleen N. Simpson, Kathy J. Texas State Univ Dept Hlth & Human Performance San Marcos TX 78666 USA Incheon Natl Univ Div Hlth & Kinesiol Incheon South Korea Univ Georgia Dept Kinesiol Athens GA 30602 USA Oregon State Univ Dept Athlet Training & Kinesiol Corvallis OR 97331 USA

The purpose of the present study was to examine the effect of chronic ankle instability (CAI) on lower-extremity joint coordination and stiffness during landing. A total of 21 female participants with CAI and 21 pair-matched healthy controls participated in the study. Lower-extremity joint kinematics were collected using a 7-camera motion capture system, and ground reaction forces were collected using 2 force plates during drop landings. Coupling angles were computed based on the vector coding method to assess joint coordination. Coupling angles were compared between the CAI and control groups using circular Watson-Williams tests. Joint stiffness was compared between the groups using independent t tests. Participants with CAI exhibited strategies involving altered joint coordination including a knee flexion dominant pattern during 30% and 70% of their landing phase and a more in-phase motion pattern between the knee and hip joints during 30% and 40% and 90% and 100% of the landing phase. In addition, increased ankle inversion and knee flexion stiffness were observed in the CAI group. These altered joint coordination and stiffness could be considered as a protective strategy utilized to effectively absorb energy, stabilize the body and ankle, and prevent excessive ankle inversion. However, this strategy could result in greater mechanical demands on the knee joint.

关键词： lower extremity nonlinear analysis ankle sprains vector coding

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Hip-Knee Joint Coordination Patterns are Associated With Patellofemoral Joint Cartilage Composition in Patients With Anterior Cruciate Ligament Reconstruction

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JOURNAL OF APPLIED BIOMECHANICS 2022年第1期38卷 20-28页

作者： Samaan, Michael A. Pedoia, Valentina Tanaka, Matthew S. Souza, Richard B. Ma, C. Benjamin Li, Xiaojuan Univ Kentucky Dept Kinesiol & Hlth Promot Lexington KY 40506 USA Univ Calif San Francisco Dept Radiol & Biomed Imaging Musculoskeletal Quantitat Imaging Res Grp San Francisco CA 94143 USA Univ Calif San Francisco Dept Phys Therapy & Rehabil Sci San Francisco CA 94143 USA Univ Calif San Francisco Dept Orthopaed Surg San Francisco CA USA Cleveland Clin Dept Biomed Engn Cleveland OH 44106 USA

Joint coordination variability during walking that is associated with patellofemoral joint cartilage degeneration after anterior cruciate ligament reconstruction are not well understood. The purpose of this study was to assess between-limb differences in joint coordination variability and to determine the relationship of coordination variability with postoperative patellofemoral joint cartilage composition. Thirty-five patients underwent bilateral gait analysis and a magnetic resonance exam of the reconstructed knee joint at 6 months post anterior cruciate ligament reconstruction. vector coding was used to assess coordination variability during the early (1%-33%), mid (34%-66%), and late (67%-100%) stance phase. The T1 /T2 mapping was used to evaluate the glycosaminoglycan-collagen matrix of the patellar and femoral trochlear cartilage. Compared with the uninjured limb, the reconstructed limb exhibited higher hip sagittal/knee sagittal plane coordination variability during midstance as well as higher knee sagittal/ankle sagittal plane coordination variability during both mid and late stance. The hip sagittal/knee sagittal plane coordination variability during midstance predicted 14.6% of the variance in patellar cartilage T1 values within the reconstructed limb. In addition, sex of participants was able to predict 32.4% and 13.7% of the variance in femoral trochlea T1 and T2 values, respectively. The study results demonstrate that a multijoint mechanism may be associated with early patellofemoral joint cartilage degeneration at 6 months after anterior cruciate ligament reconstruction.

关键词： vector coding ACL-reconstruction gait T1(p) T-2

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Low back pain affects coordination between the trunk segments but not variability during running

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JOURNAL OF BIOMECHANICS 2020年第0期101卷 109605-000页

作者： Pelegrinelli, Alexandre R. M. Silva, Mariana F. Guenka, Leandro C. Carrasco, Aline C. Moura, Felipe A. Cardoso, Jefferson R. Univ Estadual Londrina Lab Biomech & Clin Epidemiol PAIFIT Res Grp Av Robert Kock 60 BR-86038440 Londrina Parana Brazil Univ Estadual Londrina Lab Appl Biomech Londrina Parana Brazil

This study aimed to analyze the coordination and variability between the thorax, lumbar, and pelvis segments in runners with chronic low back pain group (LBPG) and matched control group (CG). Twenty-six recreational runners were evaluated on a treadmill at 33 m/s. The coordination of the pelvis-lumbar and lumbar-thorax in all three planes and between the transverse and frontal plane of the lumbar segment were evaluated using the vector coding technique. Coordination was analyzed via histograms with the percentage of each pattern and the coupling angle during the cycle. The variability coordination was calculated from the angular deviation between the cycles. Differences were observed in the coordination patterns and in the coupling angle during the cycle. Between the pelvis-lumbar in the frontal plane, the LBPG ((x) over bar = 50.6% (SD = 10.7)) presented more in-phase pattern than the CG (38.6% (8.7;P = 0.05). For the lumbar-thorax, differences occurred in all planes. Between the frontal-transverse plane of the lumbar segment, the LBPG (27.6% (7.9)) presented more in-phase pattern than the CG (38.6% (8.7): P = 0.02). The variability did not demonstrate the differences between the groups;these differences were observed in coordination between the lumbar and adjacent segments in all planes. The model of rigid segments and the coordination analyses were sensitive to detect these differences, and the presence of more in-phase patterns could be related to the protection mechanism in order to avoid painful movements. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Running vector coding Variability Lumbar Pain

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Trunk Coordination in Dancers and Nondancers

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JOURNAL OF APPLIED BIOMECHANICS 2014年第4期30卷 547-554页

作者： Jarvis, Danielle N. Smith, Jo Armour Kulig, Kornelia Univ So Calif Div Biokinesiol & Phys Therapy Los Angeles CA 90089 USA

Variability, or how a task changes across trials, may reveal differences between athletes of differing skill levels. The purpose of this study was to examine trunk and lower extremity (LE) single joint kinematic variability and intersegmental coordination variability in dancers and nondancers during bipedal vertical dance jumps (sautes). Twenty healthy females, 10 with no formal dance training and 10 professional dancers, performed 20 consecutive sautes. Single joint kinematic variability was assessed using mean standard deviation of angular displacement, and intersegmental coordination variability was assessed using angular deviation of the coupling angle between segments. Within the context of the standard error of measure, there was no difference in single joint kinematic variability between dancers and nondancers. Intersegmental coordination variability in the trunk was higher than variability in LE couplings for both groups. Dancers had lower intersegmental coordination variability than nondancers for LE sagittal, frontal, and transverse plane couplings, and sagittal plane trunk couplings. Trunk adjustments may be important for successful performance, but lower intersegmental coordination variability in expert dancers indicates a higher level of control. Trunk coordination and postural control may be important factors to investigate in skilled athletes.

关键词： dance variability vector coding jumping

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The effects of fatigue on lower extremity kinematics, kinetics and joint coupling in symptomatic female runners with iliotibial band syndrome

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CLINICAL BIOMECHANICS 2016年 39卷 84-90页

作者： Brown, Allison M. Zifchock, Rebecca A. Hillstrom, Howard J. Song, Jinsup Tucker, Carole A. Rutgers Biomed & Hlth Sci Dept Rehabil & Movement Sci Newark NJ USA US Mil Acad Dept Civil & Mech Engn West Point NY 10996 USA Hosp Special Surg MD Mot Anal Lab Leon Root 535 E 70th St New York NY 10021 USA Temple Univ Gait Study Ctr Sch Podiatr Med Philadelphia PA 19122 USA Temple Univ Dept Phys Therapy Philadelphia PA 19122 USA

Background: Altered hip and knee kinematics and joint coupling have been documented in runners with iliotibial band syndrome. Symptoms often present themselves after several minutes of running, yet the effect of fatigue warrants further exploration. The purpose of this study was to determine the effect of a run to fatigue in runners with iliotibial band syndrome, as compared to healthy controls. Methods: Twenty uninjured and 12 female runners with iliotibial band syndrome performed a treadmill run to fatigue. Prior-to and following a run to fatigue, overground running data were collected. Variables of interest included stance phase: peak hip adduction and internal rotation, peak hip abductor and external rotator joint moments and frontal-sagittal plane hip and knee joint coupling. Findings: Fatigue resulted in decreased peak hip adduction angles in injured runners. Fatigue did not affect injured runners differently than controls with respect to the remaining variables. Coupling differences did not exist between healthy and injured runners with respect to the loading or propulsive phases of stance. Interpretation: While clinicians often strengthen hip abductor muscles and provide gait re-training to decrease stance phase hip adduction, our results suggest that, when exerted, female runners with iliotibial band syndrome independently modify their running gait to decrease hip adduction, potentially as a result of pain. Fatigue did not have an effect on the remaining study variables. It is possible that reducing the length of the iliotibial band through minimizing hip adduction reduces pain, but the other variables examined are not sensitive to this phenomenon. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： Running injury Fatigue Hip vector coding

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Effect of Age on Thoracic, Lumbar, and Pelvis Coordination During Trunk Flexion and Extension

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JOURNAL OF APPLIED BIOMECHANICS 2022年第3期38卷 170-178页

作者： Kakar, Rumit S. Higgins, Seth Tome, Joshua M. Knight, Natalie Finer, Zachary Doig, Zachary Li, Yumeng Oakland Univ Dept Human Movement Sci Rochester MI 48063 USA Ithaca Coll Dept Phys Therapy Ithaca NY 14850 USA Elite Performance & Rehabil Ctr Santa Barbara CA USA Texas State Univ Dept Hlth & Human Performance San Marcos TX USA

The purpose of this study was to investigate normative and age-related differences in trunk and pelvis kinematics and intersegmental coordination during sagittal plane flexion-extension. Trunk and pelvis kinematics were recorded while 76 participants performed a maximal range of motion task in the sagittal plane. Cross-correlation was calculated to determine the phase lag between adjacent segment motion, and coupling angles were calculated using vector coding and classified into one of 4 coordination patterns: in-phase, antiphase, superior, and inferior phase. A 2-way mixed-model multivariate analysis of variance was used to compare lumbar spine and pelvis angular kinematics, phase lags, and cross-correlation coefficients between groups. Young participants exhibited greater trunk range of motion compared with middle-aged participants. The lumbar spine and pelvis were predominantly rotating with minimum phase lag during flexion and extension movement for both age groups, and differences in coordination between the groups were seen during hyperextension and return to upright position. In conclusion, middle-aged adults displayed lower range of motion but maintained similar movement patterns to young adults, which could be attributed to protective mechanisms. Healthy lumbar and pelvis movement patterns are important to understand and need to be quantified as a baseline, which can be used to develop rehabilitation protocols for individuals with spinal ailments.

关键词： vector coding cross-correlations spine biomechanics

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Stable Coordination Variability in Overground Walking and Running at Preferred and Fixed Speeds

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JOURNAL OF APPLIED BIOMECHANICS 2021年第4期37卷 299-303页

作者： Wyatt, Hannah E. Weir, Gillian Jewell, Carl van Emmerik, Richard E. A. Hamill, Joseph Auckland Univ Technol Sports Performance Res Inst New Zealand Auckland New Zealand Univ Massachusetts Biomech Lab Amherst MA 01003 USA Univ Massachusetts Motor Control Lab Amherst MA 01003 USA

Coordination variability (CV) is commonly analyzed to understand dynamical qualities of human locomotion. The purpose of this study was to develop guidelines for the number of trials required to inform the calculation of a stable mean lower limb CV during overground locomotion. Three-dimensional lower limb kinematics were captured for 10 recreational runners performing 20 trials each of preferred and fixed speed walking and running. Stance phase CV was calculated for 9 segment and joint couplings using a modified vector coding technique. The number of trials required to achieve a CV mean within 10% of 20 strides average was determined for each coupling and individual. The statistical outputs of mode (walking vs running) and speed (preferred vs fixed) were compared when informed by differing numbers of trials. A minimum of 11 trials were required for stable mean stance phase CV. With fewer than 11 trials, CV was underestimated and led to an oversight of significant differences between mode and speed. Future overground locomotion CV research in healthy populations using a vector coding approach should use 11 trials as a standard minimum. Researchers should be aware of the notable consequences of an insufficient number of trials for overall study findings.

关键词： vector coding segment coupling joint coupling reliability

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Increased movement variability in one-leg hops about 20 years after treatment of anterior cruciate ligament injury

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CLINICAL BIOMECHANICS 2018年 53卷 37-45页

作者： Srinivasan, Divya Tengman, Eva Hager, Charlotte K. Umea Univ Dept Community Med & Rehabil Physiotherapy Umea Sweden Virginia Polytech Inst & State Univ Dept Ind & Syst Engn Blacksburg VA 24061 USA

Background: Recent studies highlight the need for understanding movement control of adjacent joints when evaluating knee function following anterior cruciate ligament (ACL) injury. However, while short-term adaptations to lower-extremity joint coupling have been studied, little is known about any potential long-term adaptations in neuromuscular control displayed by ACL-injured individuals. The aim of our study was to determine whether coordination variability of the hip-knee joint couplings during the one-leg hop is altered about 20 years after injury in two ACL-injured groups compared to healthy knee controls. Methods: Seventy persons performed one leg hops 23 years after ACL injury and following different treatments: 33 participants treated with physiotherapy in combination with ACL-reconstruction (ACLR);37 participants with physiotherapy alone (ACLRT). They were compared to 33 matched controls. A vector coding procedure was used to create joint couplings for knee and hip angles on all the cardinal planes for the Take-off and Landing phases. The standard deviation of each coupling was computed as a measure of coordination variability. Findings: Both the ACL groups differed significantly from controls on their injured side with 50% higher knee abduction-adduction/hip internal-external rotation variability during the Take-off phase;33% higher knee abduction-adduction/knee flexion-extension variability and greater knee abduction-adduction/hip flexion-extension variability (ACLR 50%;ACLPT 80%) during the Landing phase. There were no major differences between injured and non-injured sides in any group. Interpretation: Increased variability in lower-extremity joint couplings has emerged as a conspicuous feature of ACL injured persons in the very long term compared to non-injured controls, independent of treatment. Further research of the processes leading to alterations in movement variability using longitudinal studies would facilitate better understanding of the funct

关键词： vector coding Movement variability Kinematics ACL reconstruction Physiotherapy

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Acetabular cartilage defects cause altered hip and knee joint coordination variability during gait

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CLINICAL BIOMECHANICS 2015年第10期30卷 1202-1209页

作者： Samaan, Michael A. Teng, Hsiang-Ling Kumar, Deepak Lee, Sonia Link, Thomas M. Majumdar, Sharmila Souza, Richard B. Univ Calif San Francisco Dept Radiol & Biomed Imaging Musculoskeletal Quantitat Imaging Res Grp San Francisco CA 94107 USA Med Univ S Carolina Coll Hlth Profess Div Phys Therapy Charleston SC 29425 USA Univ Calif San Francisco Dept Phys Therapy & Rehabil Sci San Francisco CA 94158 USA

Background: Patients with acetabular cartilage defects reported increased pain and disability compared to those without acetabular cartilage defects. The specific effects of acetabular cartilage defects on lower extremity coordination patterns are unclear. The purpose of this study was to determine hip and knee joint coordination variability during gait in those with and without acetabular cartilage defects. Methods: A combined approach, consisting of a semi-quantitative MRI-based quantification method and vector coding, was used to assess hip and knee joint coordination variability during gait in those with and without acetabular cartilage lesions. Findings: The coordination variability of the hip flexion-extension/knee rotation, hip abduction-adduction/knee rotation, and hip rotation/knee rotation joint couplings were reduced in the acetabular lesion group compared to the control group during loading response of the gait cycle. The lesion group demonstrated increased variability in the hip flexion-extension/knee rotation and hip abduction-adduction/knee rotation joint couplings, compared to the control group, during the terminal stance/pre-swing phase of gait. Interpretation: Reduced variability during loading response in the lesion group may suggest reduced movement strategies and a possible compensation mechanism for lower extremity instability during this phase of the gait cycle. During terminal stance/pre-swing, a larger variability in the lesion group may suggest increased movement strategies and represent a compensation or pain avoidance mechanism caused by the load applied to the hip joint. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： Acetabular cartilage lesions vector coding Joint coordination Gait Lower extremity MRI

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