Arm Length Research Articles

Static-to-kinematic modeling and experimental validation of tendon-driven quasi continuum manipulators with nonconstant subsegment stiffness

Continuum robots with high flexibility and compliance have the capability to operate in confined and cluttered environments. To enhance the load capacity while maintaining robot dexterity, we propose a novel non-constant subsegment stiffness structure for tendon-driven quasi continuum robots (TDQCRs) comprising rigid-flexible coupling subsegments. Aiming at real-time control applications, we present a novel static-to-kinematic modeling approach to gain a comprehensive understanding of the TDQCR model. The analytical subsegment-based kinematics for the multisection manipulator is derived based on screw theory and product of exponentials formula, and the static model considering gravity loading, actuation loading, and robot constitutive laws is established. Additionally, the effect of tension attenuation caused by routing channel friction is considered in the robot statics, resulting in improved model accuracy. The root-mean-square error between the outputs of the static model and the experimental system is less than 1.63% of the arm length (0.5 m). By employing the proposed static model, a mapping of bending angles between the configuration space and the subsegment space is established. Furthermore, motion control experiments are conducted on our TDQCR system, and the results demonstrate the effectiveness of the static-to-kinematic model.

Investigation of the Relationship Between Functional Skills, Sensory Functions, and Anthropometric Properties of the Hand in Occupational Therapy Students Using Hierarchical Clustering Analysis

Purpose: This study aims to examine the relationship between functional skills, sensorimotor, and anthropometric variables of the hand in health science students.
 Material and Methods: The study was carried out on 70 students (21.51± 1.59 years; 61 women, 9 men) from Biruni University. Upper extremity anthropometric measurements were taken from the students. Hand Dynamometer and Pinchmeter were used for hand grip strength, Purdue Pegboard Test for hand dexterity, Semmes-Weinstein Monofilament for two-point discrimination, and Vibration Perception Test were used for sensory functions. Hierarchical cluster analysis was employed to find the clustering trend of the variables.
 Results: At the end of the research, two main clusters were obtained, of which four sub-clusters belonging to the second one were identified. The main cluster I contains pinch, dipod, tripod, lateral grip force, Purdue pegboard dominant, non-dominant, both, and assembly. Main cluster II contains finger lengths, palmar length, hand grip, total upper extremity length, height, two-point discrimination, vibration, weight, BMI, monofilament, palmar width, segmental arm, forearm, and hand length.
 Conclusion: As a result of the research, it was determined that pinch grip strength, dexterity, anthropometric and sensory characteristics were related to each other.

LISAmax: improving the low-frequency gravitational-wave sensitivity by two orders of magnitude

Within its Voyage 2050 planning cycle, the European Space Agency is considering long-term large class science mission themes. Gravitational-wave astronomy is among the topics under study. Building on previous work by other authors (Folkner 2011 (NNH11ZDA019L); Ni 2010 Mod. Phys. Lett. A 25 922–35; Sesana et al 2021 Exp. Astron. 51 1333–83), this paper studies a gravitational-wave interferometer concept, dubbed ‘LISAmax’, consisting of three spacecraft, each located close to one of the Sun–Earth libration points L3, L4 and L5, forming a triangular constellation with an arm length of 259 million kilometers (to be compared to LISA’s 2.5 million kilometer arms). We argue that this is the largest triangular formation that can be reached from Earth without a major leap in mission complexity and cost (hence the name). The sensitivity curve of such a detector is at least two orders of magnitude lower in amplitude than that of LISA, at frequencies below 1 mHz. This makes the observatory sensitive to gravitational waves in the µHz range and opens a new window for gravitational-wave astronomy, not covered by any other planned detector concept. We analyze in detail the constellation stability for a 10 year mission in the full numerical model including insertion dispersion, and self-gravity-induced accelerations. We compute the orbit transfers using a European launcher and chemical propulsion. Different orbit options, such as precessing, inclined orbits, the use of flybys for the transfer, and the launch strategy, are discussed. The payload design parameters are assessed, and the expected sensitivity curve is compared with a number of potential gravitational-wave sources. No show stoppers are identified at this point of the analysis.

Evaluation of radiologic predisposing factors for greater trochanteric pain syndrome

Objectives: Greater trochanteric pain syndrome (GTPS) is one of the causes of lateral hip pain. We aimed to determine the significance of certain anatomical parameters related to GTPS in imaging tests. Methods: Data of patients who were treated with glucocorticoid injection for trochanteric bursitis in our clinic between July 2019 and July 2022 for GTPS were analyzed. The control group was constituted of patients without GTPS but with hip and spinal problems who had pelvic computerized tomography (CT) images and undergone robotic-assisted knee arthroplasty. Standard anteroposterior pelvic radiograms, pelvic CTs, or magnetic resonance images were evaluated for anatomical parameters. Results: Among anatomical parameters, acetabular anteversion, length of trochanter major, and abductor index were significantly different between the patients with and without GTPS. Although mean age was different between the GTPS and control patient groups, age was not found to be correlated with any anatomical parameter. Abductor lever arm length (p = 0.001) and abductor index (p = 0.009) were found to be correlated. Conclusions: The length of trochanter major and abductor index were shown to be predisposing anatomical parameters for GTPS.

Anatomical Variations of the Musculocutaneous Nerve in the Human Fetus

Knowing the motor branches and variations of the musculocutaneous nerve to the muscles along its course will facilitate the treatment of flexor spasticity and supracondylar fractures of the humerus in order to minimize nerve lesion. In fetal cadavers, the purpose of our study was to determine the number and course of the formation variations and motor branches of the musculocutaneous nerve. The significance of studying fetal nerve variations is due to injury to the brachial plexus roots during birth. Our study was conducted using the anatomical dissection technique on 102 upper limbs from 51 fetuses ages ranged from 17 to 40weeks. Throughout its course, the variations and motor branches of the musculocutaneous nerve were analyzed. In 13.7% of cases, the musculocutaneous nerve did not pierce the coracobrachialis. The musculocutaneous nerve gave the muscles 1-3 motor branches. Additionally, motor branches terminated with 1-7 fringes. The biceps brachii motor branches of the musculocutaneous nerve were typed. Accordingly, 15.6% were type 1A, 3.9% were type 1B, 35.4% were type 1C, and 19.6% were type 1D. It was determined that 23.5% of the extremities were type 2 and that 1.9% were type 3. The distance between the musculocutaneous nerve's motor branches and the acromion was proportional to the arm's length. There were no statistically significant differences between the sides and genders for any measurement. Our study's findings will aid in the diagnosis and treatment of pediatrics, orthopedics, surgical sciences, and radiology conditions. It reduces the risk of iatrogenic injury and postoperative complications. We also believe that our research will serve as a resource for anatomists and other scientists.

Overview of KAGRA : Data transfer and management

Abstract KAGRA is a newly built gravitational wave observatory, a laser interferometer with a 3 km arm length, located in Kamioka, Gifu prefecture, Japan. In this article, we describe the KAGRA data management system, i.e., recording of data, transfer from the KAGRA experiment site to computing resources, as well as data distribution to tier sites, including international sites in Taiwan and Korea. The amount of KAGRA data exceeded 1.0 PiB and increased by about 1.5 TB per day during operation in 2020. Our system has succeeded in data management, and has achieved performance that can withstand observations after 2023, that is, a transfer rate of 20 MB s-1 or more and file storage of sufficient capacity for petabyte class. We also discuss the sharing of data between the global gravitational-wave detector network with other experiments, namely LIGO and Virgo. The latency, which consists of calculation of calibrated strain data and transfer time within the global network, is very important from the view of multi-messenger astronomy using gravitational waves. Real-time calbrated data delivered from the KAGRA detector site and other detectors to our computing system arrive with about 4–15 seconds of latency. These latencies are sufficiently short compared to the time taken for gravitational wave event search computations. We also established a high-latency exchange of offline calibrated data that was aggregated with a better accuracy compared with real-time data.

At Arm's Length: A Rhetoric of Character in Children's and Young Adult Literature by Mike Cadden (review)

At Arm's Length: A Rhetoric of Character in Children's and Young Adult Literature by Mike Cadden (review)

Enhancing Electro-Hydraulic Load Simulator Performance Through Variable Arm Length and Particle Swarm-Optimized Controllers

This study presents a novel approach to improve the loading characteristics of an electro-hydraulic load simulator by introducing a variable arm length mechanism and employing advanced control strategies rooted in Particle Swarm Optimization (PSO). The design enhancements focus on optimizing the physical connection between the steering gear system and the load system, resulting in an electro-hydraulic load simulator equipped with adjustable arm length. Through a meticulous analysis of the ideal pivot position for the rocker lever, a fuzzy Proportional-Integral-Derivative (PID) controller based on PSO has been developed for the steering gear system. In recognition of the PSO algorithm’s susceptibility to local optima convergence, a fuzzy PID controller employing Single-Particle Random Search (SSPSO) has also been devised for the load system. To assess the effectiveness of this innovative hardware configuration and controller implementation in mitigating over-suppression, comprehensive joint simulation experiments were conducted. The results unequivocally indicate that the incorporation of the variable arm length structure, along with the PSO-based fuzzy PID controller optimized using binding factors, substantially enhances the dynamic loading performance of the electro-hydraulic load simulator. This enhancement translates into superior loading accuracy and overall performance metrics, establishing this research as a valuable reference for future investigations in this field.

Validity and Reliability of the Kinvent Handheld Dynamometer in the Athletic Shoulder Test.

Long-lever shoulder strength tests may aid clinical decision-making regarding return to sport after a shoulder injury. The Athletic Shoulder Test (AST) was developed to measure force production in 3 positions of shoulder abduction (90°, 135°, and 180°) using force plates. However, handheld dynamometers (HHDs) are more portable, affordable, and may provide valid and reliable results which would increase the clinical utility of long-lever tests. HHDs vary in shape, design, and their capacity to report parameters such as rate of force production and require further investigation. The aim of this study was to examine the intrarater reliability of the Kinvent HHD and assess its validity against Kinvent force plates in the AST. Peak force (in kilograms), torque (in Newton meters), and normalized torque (in Newton meters per kilogram) were reported. Validity and reliability study. Twenty-seven participants with no history of upper limb injury performed the test in a randomized order using the Kinvent HHD and force plates. Each condition was assessed 3 times, and peak force was recorded. Arm length was measured to calculate peak torque. Normalized peak torque was calculated by dividing torque by bodyweight (in kilograms). The Kinvent HHD is reliable when measuring force (intraclass correlation coefficient [ICC] ≥ .80), torque (ICC ≥ .84), and normalized torque (ICC ≥ .64) during the AST. The Kinvent HHD is also valid when compared with the Kinvent force plates for force (ICC ≥ .79; r ≥ .82), torque (ICC ≥ .82; r ≥ .76), and normalized torque (ICC ≥ .71; r ≥ .61). There were no statistically significant differences across the 3 trials on analyses of variance (P > .05). The Kinvent HHD is a reliable tool when used to measure force, torque, and normalized torque in the AST. Furthermore, given the lack of significant difference between trials, clinicians can use one test to accurately report relative peak force/torque/normalized torque rather than average 3 separate trials. Finally, the Kinvent HHD is valid when compared with Kinvent force plates.

Development of Handball Academy Korea Physical Fitness Test Model for Youth Handball Players

PURPOSE: This study aimed to develop a Handball Academy Korea Physical Fitness Test Battery for youth handball athletes considering their characteristics using the Delphi/AHP method.METHODS: After reviewing previous studies, an expert meeting was held to draft a battery. To select physical fitness variables, 17 experts with more than 10 years of research or coaching experience in related fields were invited. The contact validity of each variable was verified using the 1st and 2nd Delphi surveys. A decision-making method based on the analytic hierarchy process (AHP) was used to assign weights to each factor in the final physical fitness battery, which was selected based on the results of the Delphi survey.RESULTS: Ten physical fitness factors, namely, length (CVR=1.00), weight (CVR=0.67), muscle strength (CVR=0.67), muscular endurance (CVR=0.83), cardiorespiratory fitness (CVR=0.83), flexibility (CVR=0.67), power (CVR=1.00), agility (CVR=1.00), speed (CVR=0.80), coordination (CVR=1.00), were determined. As test variables for physical fitness, height (CVR=0.83), arm span (CVR=0.67), lean body mass (CVR=0.64), handgrip strength (CVR=0.83), push-up (CVR=0.67), 20 m shuttle run (CVR=1.00), sitand-reach (CVR=0.83), standing long jump (CVR=0.76), countermovement jump (CVR=0.67), ball speed (CVR=0.67), rollercoaster run (CVR=0.83), visual reaction (CVR=0.83), 20 m sprint (CVR=0.83), and ball handling (CVR=0.67) were found to be valid. Weight was calculated according to the relative importance of the determined variables.CONCLUSIONS: The present findings indicate that the Handball Academy Korea Physical Fitness Test Battery can be used to evaluate the physical fitness of youth handball athletes and select potential players.

A Geometric Analysis of Relativity

Relativity’s mathematical models are based upon the MichelsonMorley Interferometer Experiment of 1887. Wikipedia provides an illustration of the interferometer and a description of the experiment: A ray of light traveling at velocity, c, was reflected from one mirror to another at a distance, L (the length of the interferometer arms), in an attempt to measure movement of the earth relative to light, v.

Antenna Array with Low Side Lobe Levels for MIMO Applications

Abstract: To design a single element microstrip patch antenna at a frequency of 4 GHz. A uniform planar array with 4 patch elements is designed. A non uniform planar array is designed to overcome the mutual coupling effect. Simulation of the designed uniform planar array and non uniform planar array antenna array is performed on HFSS tools. A single microstrip feed patch antenna element is designed at a frequency of 4 GHz. The substrate material used is Rogers 6002. A 2*2 array is designed by using 4 similar patch elements. The proposed model has dimensions of the substrate as 58mm x 68mm, the dimensions of the patch is 20mm x 22mm. For the proposed model slots are added to each patch with the dimensions 5mm x 1mm. The substrate material used is FR4 epoxy. It is further improved by changing the dielectric material variations, slot arm length variations, slot arm thickness variations.

Reaksi Pasar Saham di Indonesia terhadap Keterbukaan Informasi Terkait Transaksi Afiliasi

Affiliated transaction or also known as related party transaction (RPT) refers to a transaction involving two or more parties with a special or related relationship. Due to this relationship, the transactions may not be conducted according to the arm's length principle or cause a potential agency problem. Therefore, information disclosure to the public is necessary to provide a material information regarding affiliated transactions and as a key aspect of adhering to principles of good corporate governance. The aim of this study is to analyze whether there is a significant and positive impact on Indonesian stock market, in response to the RPT Announcements by issuers in Indonesia. Despite the prevalence of affiliated transactions among group companies in Indonesia, there is little research focused on the impact of RPT announcements on stock market reactions in Indonesia. Using event study as the method, in this study assess whether stock prices adjust in a timely manner upon the arrival of new public information. The results indicate that there is a significant and positive average abnormal return on the third trading day before RPT Announcement, and a significant and negative average abnormal return on the fourth trading day after RPT Announcement. 
 
 Keywords: Stock market reaction, RPT announcement, affiliated transaction, event study

Temperature and strain simultaneous sensing measurement based on an all-fiber Mach-Zehnder interferometer and fiber Bragg grating.

We designed and fabricated what we believe to be a novel dual-parameter fiber optic sensor for simultaneous measurement of temperature and strain, which was composed of a femtosecond laser inscribed fiber Bragg grating (FBG), three segments of a single-mode fiber (SMF), and two segments of a multimode fiber (MMF), forming a SMF-MMF-FBG-MMF-SMF structure. The FBG and Mach-Zehnder interferometer (MZI) were present in this structure so that the changes of the temperature and strain parameters can be sensed by the shifts of the reflection center wavelength of the FBG and the interference valley wavelength of the MZI. We simulated the light field distribution of the sensor structure, compared the shapes of the interference spectra formed by the MZI structure with different sensing arm lengths of 25, 35, and 45mm, and analyzed the spectra in the spatial frequency domain. The simulation results showed that the interference spectrum of the MZI structure with a 25mm length sensing arm was clearer and more suitable for the experiment. The experimental results showed that the temperature sensitivity of the FBG and MZI was 14.81 and 43.54pm/°C in the range of 80°C to 240°C, and the strain sensitivity was 1.49 and -2.58pm/µε in the range of 0 to 1200µε, with a high linearity and excellent repeatability. The sensor is economical, sensitive, and convenient to fabricate, and exhibits promising applications in the fields of biochemical medical detection and industrial production monitoring.

Modified bow-tie antenna array with efficient electric near-field enhancement for terahertz band

Antenna arrays can induce strong electric near-field enhancement to improve the performance of biological imaging resolution, macromolecule detection sensitivity, and sensing accuracy. However, the use of antenna arrays to regulate both the electric near-field enhancement factor and area has rarely been reported. In this paper, a novel modified bow-tie (MBT) antenna array is proposed for better near-field enhancement performance in terahertz (THz) regime. Using commercially available high frequency structure simulator (HFSS), the dimensions of the MBT antenna array, including gap width, arm length, array period, and substrate thickness, are optimized to improve electric near-field enhancement performance in terms of higher factor, larger area, more controllable peak frequency, and wider 1-dB bandwidth. The as-optimized MBT and bow-tie (BT) THz antenna arrays are fabricated on quartz substrate via lithography and lift-off process. The normalized transmittances of the MBT and BT antenna arrays are characterized by THz time-domain spectroscopy (THz-TDS) and compared with the corresponding simulated near-field enhancement factor and normalized transmittance. The results indicate that the MBT antenna array outperforms the BT antenna array with a three-fold increase in near-field enhancement area and a 66.7% wider 1-dB bandwidth, and therefore can be used to enhance detection sensitivity and sensing accuracy in weak terahertz environment.

Selective Construction of Borromean Rings andTweezer‐LikeMolecular Assembly Featuring Cp*Rh/Ir Clips forNear‐InfraredPhotothermal Conversion†

Comprehensive SummaryMaking full use of coordination‐driven self‐assembly strategy, we herein described the selective synthesis of a molecular Borromean rings and two cases of “U”‐shaped tweezer‐like molecular assemblies in high yield by using bipyridyl ligands based on biphenyl unit and half‐sandwich binuclear rhodium(III)/iridium(III) building blocks. The selective synthesis was realized by adjusting the length of dipyridyl arms. The utilization of curved U‐shaped bipyridyl ligandL1led to tweezer‐like molecular assemblies. Subsequently, olefinic bonds were introduced to elongate dipyridyl arms obtaining ligandL2. The ligandL2has two stable conformations, U‐shape and Z‐shape, which facilitated the formation of different topologies including the tetranuclear macrocycle and Borromean rings with different building blocks in this work. These structures in solid and solution all have been further confirmed by single‐crystal X‐ray diffraction, NMR analysis, and mass spectrometry. In addition, as an important driving force, π‐π stacking interactions not only played a significant role in the stability of structures but also further triggered photothermal conversion in solution. The experimental results demonstrated that compounds1aand2had good NIR photothermal conversion efficiency (11.83% and 17.76%), and further analysis found the photothermal conversion efficiency had a gradual increase in the trend with the π‐π stacking interactions increasing. This research expands the application of topological structures in materials science and provides a new idea for the synthesis of novel photothermal conversion materials.

An Art for Art's Sake or a Critical Concept of Art's Autonomy? Autonomy, Arm's Length Distance, and Art's Freedom

What is the relationship between the philosophical concept of the “autonomy of art” and the cultural policy-notion of “artistic freedom”? This article seeks to answer this question by taking the Swedish governmental report This Is How Free Art Is (Så fri är konsten 2021) and its reception in the Swedish main stream media as an emblematic example and by reading it symptomatically. Firstly, it traces the critical history of “artistic freedom” and the interrelated term “arm’s length distance”, primarily in the context of Great Britain. Secondly, it critically reconstructs the concept of the “autonomy of art” in the history of Western philosophy by making a critique of a fetishized notion of art’s autonomy in the name of l’art pour l’art. The main argument is that the idea about art’s autonomy, on which the Swedish report leans, resembles such philosophical and art historical idea of art’s autonomy. The claim is also that such an understanding of art does not tie up, either philosophically or historically, with the arm’s length principle, since they ultimately rely on different conceptions of art’s freedom.

Influence of side chain lengths in mechanophore‐containing polyisobutylene‐graft‐polystyrene

AbstractPolymer architecture plays an important role in morphology and mechanochemical response. Here, graft copolymers containing mechanophores at the backbone‐arm junction are synthesized through a combination of post‐polymerization modification of butyl rubber and controlled radical polymerization. A series of graft copolymers with 70:30 or 50:50 polyisobutylene:polystyrene (PIB:PS) volume fractions were synthesized by changing the grafting density and arm length to keep the volume fractions constant. The morphologies for these polymers are disordered but show a decreasing domain size with shorter arm lengths, and the samples with a greater number of PS side chains show greater domain mixing. Using pulsed ultrasound experiments, we found greater backbone scission occurs for polymers with a greater number of short grafts per chain than the long grafts with fewer grafting points. Finally, mechanophore activation is greater for samples with arm molecular weights ≥13 kg/mol, attributed to exceeding the cutoff molecular weight for PS.

Automatic Digitization of JMA Strong-Motion Seismograms Recorded on Smoked Paper: An Attempt Using Deep Learning

Abstract Using deep learning, an attempt was made to automatically digitize waveforms in scanned Japan Meteorological Agency (JMA) analog seismograms of strong-motion seismographs recorded on smoked paper. We manually traced the waveforms in the scanned images to be used as supervised data for a convolutional neural network (CNN) model using these images. In the analog recording system, ground shaking was recorded on paper with a needle attached to the end of an arm. Because the other end of the arm is fixed on a pivot, the needle moves in an arc around the pivot for large shaking compared to the arm length. We carefully considered the effects of the finite arm length in the analog system and trained the CNNs. To validate the learning results, the trained CNN model was applied to images that were not used for the training. The automatic digitization by our method works fairly well, except for seismograms rich in high-frequency components and those with long-period large amplitudes. Even these images can be well digitized by resizing the image height by, for example, 1/2. To further improve the accuracy of automatic digitization, it would be effective to prepare many additional input and supervised data, and retrain the model. Other training is also necessary for other types of seismographs that have features and characteristics different from strong-motion seismograms.

Reassessing the Proportional System of Joseon Era Wooden Architecture: The Bracket Arm Length and Width as a Standard Modular Method

Previous research has agreed that standard modular methods in Song Yingzao Fashi and Qing Gongcheng Zuofa were not applied to Korean wooden architecture. This study notes the size of bracket arms as a standard modular method by investigating the proportion systems of Sungnyemun, Paldalmun, and Heunginjimun Gates, the official government buildings of the Joseon Dynasty. The purlin direction bracket arms in the intercolumnar bracket sets apply a proportional system in the ratio of a regular integer relationship to the front and side facades and building height. Challenging current assumptions, the application of the bracket arm width as a modular rule is divided into more subdivided values than the measurement units. A particularly important finding is that, unlike the height of the bracket arms, the width and length of the brackets are standard members that determine the height of the side facades. This is very similar to the official government building styles in the Song and Qing Dynasties, premodern China. Therefore, this study is meaningful in reassessing wooden frame structures of the Joseon era, deriving parametric measuring rules universally applied in East Asia to provide basic data useful for heritage conservation.