31 research outputs found
Quasi-Static Analysis on Transoral Surgical Tendon-Driven Articulated Robot Units
Wire actuation in tendon-driven continuum robots enables the transmission of
force from a distance, but it is understood that tension control problems can
arise when a pulley is used to actuate two cables in a push-pull mode. This
paper analyzes the relationship between angle of rotation, pressure, as well as
variables of a single continuum unit in a quasi-static equilibrium. The primary
objective of the quasi-static analysis was to output pressure and the analysis,
given the tensions applied. Static equilibrium condition was established, and
the bisection method was carried out for the angle of rotation. The function
for the bisection method considered pressure-induced forces, friction forces,
and weight. {\theta} was 17.14{\deg}, and p was 405.6 Pa when Tl and Ts were
given the values of 1 N and 2 N, respectively. The results seemed to be
consistent with the preliminary design specification, calling for further
simulations and experiments
Recommended from our members
RETROGRADE TGF-β SIGNALING AND ITS EFFECTS ON WD40 AT THE DROSOPHILA NEUROMUSCULAR JUNCTION
TGF-β signaling is particularly well studied for its role in early embryonic patterning and cell proliferation specific to cancer progression. At the larval neuromuscular junction (NMJ) of the model organism Drosophila melanogaster, several ligands from the TGF-β superfamily have been shown to promote synaptic growth and evoked neurotransmitter release. We focused on the retrograde bone morphogenic protein (BMP) signaling pathway and its potential role for the presynaptic expression of WD40, a potential cofactor of the E3 ubiquitin ligase Cullin 4 (Cul4) that is required for evoked neurotransmitter release. The goal of this project was to investigate whether this TGF-β signaling pathway regulates the expression of WD40. In conclusion, our data shows evidence that WD40 might a critical effector of retrograde BMP signaling at Drosophila NMJs
A Novel Biometric Identification Based on a User's Input Pattern Analysis for Intelligent Mobile Devices
As intelligent mobile devices become more popular, security threats targeting them are increasing. The resource constraints of mobile devices, such as battery life and computing power, however, make it harder to handle such threats effectively. The existing physical and behavioural biometric identification methods - looked upon as good alternatives - are unsuitable for the current mobile environment. This paper proposes a specially designed biometric identification method for intelligent mobile devices by analysing the user's input patterns, such as a finger's touch duration, pressure level and the touching width of the finger on the touch screen. We collected the input pattern data of individuals to empirically test our method. Our testing results show that this method effectively identifies users with near a 100% rate of accuracy
AVX512Crypto: Parallel Implementations of Korean Block Ciphers Using AVX-512
Cryptographic algorithms are widely used as the foundation of various security systems and applications (e.g., secure communication, blockchain systems, and cloud services). A block cipher is an essential cryptographic algorithm to achieve confidentiality. This paper proposes parallel implementations of Korean block ciphers using Advanced Vector eXtension (AVX)-512, which is a new Single instruction, multiple data (SIMD) instruction set that has recently been integrated into several high-end Intel central processing unit (CPU). Target algorithms are LEA, HIGHT, and CHAM block ciphers. Additionally, this paper also proposes applicable implementing techniques, which are designed for each algorithm. These enable to use of parallel processing instructions in AVX-512 properly for each algorithm. The proposed LEA-128 (192, 256 resp.)implementation demonstrates a performance improvement of 506.09% (323.31%, 386.76% resp.) compared to the reference code, and our HIGHT implementation exhibits a performance improvement of 520.88% compared to the reference code. In addition, CHAM-64/128 (128/256 resp.) implementation shows a performance improvement of 1,325.81% (833.61% resp.) compared to the reference code. In addition, we measured the performance with a 32MB long message. LEA-128 (192, 256 resp.) implementation showed an improvement of 556.32% (594.74%, 615.38% resp.) compared with the reference code. Also, HIGHT implementation showed 834.40%, and CHAM showed 1,332.40% (832.86% resp.) for CHAM-64/128 (CHAM-128/256 resp.), compared by the reference code. To the best of our knowledge, this is the first result of the study to optimize Korean cryptographic algorithms using the AVX-512 instruction set. The proposed methods can effectively be used in Addition, Rotation, and XOR (ARX)-based cryptographic algorithms, enabling efficient cryptographic algorithm processing in various environments such as hash-based signatures, service environments, gateway, and edge computing
Virtual daily living test to screen for mild cognitive impairment using kinematic movement analysis.
Questionnaires or computer-based tests for assessing activities of daily living are well-known approaches to screen for mild cognitive impairment (MCI). However, questionnaires are subjective and computerized tests only collect simple performance data with conventional input devices such as a mouse and keyboard. This study explored the validity and discriminative power of a virtual daily living test as a new diagnostic approach to assess MCI. Twenty-two healthy controls and 20 patients with MCI were recruited. The virtual daily living test presents two complex daily living tasks in an immersive virtual reality environment. The tasks were conducted based on subject body movements and detailed behavioral data (i.e., kinematic measures) were collected. Performance in both the proposed virtual daily living test and conventional neuropsychological tests for patients with MCI was compared to healthy controls. Kinematic measures considered in this study, such as body movement trajectory, time to completion, and speed, classified patients with MCI from healthy controls, F(8, 33) = 5.648, p < 0.001, η2 = 0.578. When both hand and head speed were employed in conjunction with the immediate free-recall test, a conventional neuropsychological test, the discrimination power for screening MCI was significantly improved to 90% sensitivity and 95.5% specificity (cf. the immediate free-recall test alone has 80% sensitivity and 77.3% specificity). Inclusion of the kinematic measures in screening for MCI significantly improved the classification of patients with MCI compared to the healthy control group, Wilks' Lambda = 0.451, p < 0.001
Wireless-Powered Chemical Sensor by 2.4 GHz Wi-Fi Energy-Harvesting Metamaterial
Metamaterial Sensors show significant potential for applications ranging from hazardous chemical detection to biochemical analysis with high-quality sensing properties. However, they require additional measurement systems to analyze the resonance spectrum in real time, making it difficult to use them as a compact and portable sensor system. Herein, we present a novel wireless-powered chemical sensing system by using energy-harvesting metamaterials at microwave frequencies. In contrast to previous studies, the proposed metamaterial sensor utilizes its harvested energy as an intuitive sensing indicator without complicated measurement systems. As the spectral energy-harvesting rate of the proposed metamaterial sensor can be varied by changing the chemical components and their mixtures, we can directly distinguish the chemical species by analyzing the resulting output power levels. Moreover, by using a 2.4 GHz Wi-Fi source, we experimentally realize a prototype chemical sensor system that wirelessly harvests the energy varying from 0 mW up to 7 mW depending on the chemical concentration of the water-based binary mixtures
Virtual daily living test to screen for mild cognitive impairment using kinematic movement analysis
Questionnaires or computer-based tests for assessing activities of daily living are well-known approaches to screen for mild cognitive impairment (MCI). However, questionnaires are subjective and computerized tests only collect simple performance data with conventional input devices such as a mouse and keyboard. This study explored the validity and discriminative power of a virtual daily living test as a new diagnostic approach to assess MCI. Twenty-two healthy controls and 20 patients with MCI were recruited. The virtual daily living test presents two complex daily living tasks in an immersive virtual reality environment. The tasks were conducted based on subject body movements and detailed behavioral data (i.e., kinematic measures) were collected. Performance in both the proposed virtual daily living test and conventional neuropsychological tests for patients with MCI was compared to healthy controls. Kinematic measures, such as body movement trajectory, time to completion, and speed, were differently classified in patients with MCI compared to healthy controls, F(8, 33) = 5.648, p < 0.001, η2 = 0.578. When both hand and head speed measures were employed in conjunction with the immediate free-recall test, a conventional neuropsychological test, the discrimination power for screening MCI was significantly improved to 90% sensitivity and 95.5% specificity (cf. the immediate free-recall test alone has 80% sensitivity and 77.3% specificity). Inclusion of the kinematic measures in screening for MCI significantly improved the classification of patients with MCI compared to healthy controls, Wilks’ Lambda = 0.451, p < 0.001
Ensemble-NQG-T5: Ensemble Neural Question Generation Model Based on Text-to-Text Transfer Transformer
Deep learning chatbot research and development is exploding recently to offer customers in numerous industries personalized services. However, human resources are used to create a learning dataset for a deep learning chatbot. In order to augment this, the idea of neural question generation (NQG) has evolved, although it has restrictions on how questions can be expressed in different ways and has a finite capacity for question generation. In this paper, we propose an ensemble-type NQG model based on the text-to-text transfer transformer (T5). Through the proposed model, the number of generated questions for each single NQG model can be greatly increased by considering the mutual similarity and the quality of the questions using the soft-voting method. For the training of the soft-voting algorithm, the evaluation score and mutual similarity score weights based on the context and the question–answer (QA) dataset are used as the threshold weight. Performance comparison results with existing T5-based NQG models using the SQuAD 2.0 dataset demonstrate the effectiveness of the proposed method for QG. The implementation of the proposed ensemble model is anticipated to span diverse industrial fields, including interactive chatbots, robotic process automation (RPA), and Internet of Things (IoT) services in the future
Resting-state electroencephalographic characteristics related to mild cognitive impairments
Alzheimer's disease (AD) causes a rapid deterioration in cognitive and physical functions, including problem-solving, memory, language, and daily activities. Mild cognitive impairment (MCI) is considered a risk factor for AD, and early diagnosis and treatment of MCI may help slow the progression of AD. Electroencephalography (EEG) analysis has become an increasingly popular tool for developing biomarkers for MCI and AD diagnosis. Compared with healthy elderly, patients with AD showed very clear differences in EEG patterns, but it is inconclusive for MCI. This study aimed to investigate the resting-state EEG features of individuals with MCI (n = 12) and cognitively healthy controls (HC) (n = 13) with their eyes closed. EEG data were analyzed using spectral power, complexity, functional connectivity, and graph analysis. The results revealed no significant difference in EEG spectral power between the HC and MCI groups. However, we observed significant changes in brain complexity and networks in individuals with MCI compared with HC. Patients with MCI exhibited lower complexity in the middle temporal lobe, lower global efficiency in theta and alpha bands, higher local efficiency in the beta band, lower nodal efficiency in the frontal theta band, and less small-world network topology compared to the HC group. These observed differences may be related to underlying neuropathological alterations associated with MCI progression. The findings highlight the potential of network analysis as a promising tool for the diagnosis of MCI