IEEE transactions on medical robotics and bionics最新文献_第8页

Enhanced EMG-Based Hand Gesture Classification in Real-World Scenarios: Mitigating Dynamic Factors With Tempo-Spatial Wavelet Transform and Deep Learning 真实世界场景中基于 EMG 的增强型手势分类：利用节奏空间小波变换和深度学习减轻动态因素的影响

IF 3.4

IEEE transactions on medical robotics and bionics Pub Date : 2024-06-03 DOI: 10.1109/TMRB.2024.3408896

Parul Rani;Sidharth Pancholi;Vikash Shaw;Manfredo Atzori;Sanjeev Kumar

{"title":"Enhanced EMG-Based Hand Gesture Classification in Real-World Scenarios: Mitigating Dynamic Factors With Tempo-Spatial Wavelet Transform and Deep Learning","authors":"Parul Rani;Sidharth Pancholi;Vikash Shaw;Manfredo Atzori;Sanjeev Kumar","doi":"10.1109/TMRB.2024.3408896","DOIUrl":"https://doi.org/10.1109/TMRB.2024.3408896","url":null,"abstract":"Dynamic factors, like limb position changes and electrode shifting, significantly impact the performance of EMG-based hand gesture classification as the transition is made from a laboratory-controlled environment to real-life scenarios. Traditionally, researchers have employed conventional wavelet transform methods to improve classification performance. This study compares a tempo-spatial technique that utilizes the wavelet multiresolution method and compares it with the conventional wavelet transform using eight machine learning algorithms. Two public datasets are utilized. DB1 comprising ideal conditions with a range of limb positions, while DB2 incorporates dynamic factors like electrode shifting and muscle fatigue. The training/testing involves two cases: one using single-position data and other with multiple positions. Results demonstrate that the Deep Neural Network (DNN) classifier outperforms others in classification accuracy. Proposed technique achieves mean accuracies of 84.07% (DB1) and 68.15% (DB2), while conventional wavelet transform methods achieve 79.39% (DB1) and 53.48% (DB2) for single-position DNN training. For multiple positions, particularly two limb positions, the proposed technique achieves mean accuracies of 94.43% (DB1) and 73.79% (DB2), compared to conventional wavelet transform, which achieves 84.38% (DB1) and 51.98% (DB2) with DNN. Paired t-tests (p-value<0.001) show significant improvement over conventional wavelet transformation, indicating the proposed technique’s potential to enhance gesture classification in real-world scenarios.","PeriodicalId":73318,"journal":{"name":"IEEE transactions on medical robotics and bionics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141965576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Pose-Independent Interaction Distance Adjustment for Magnetically Driven Robotic Capsules 磁力驱动机器人胶囊的姿态无关交互距离调整

IF 3.4

IEEE transactions on medical robotics and bionics Pub Date : 2024-06-03 DOI: 10.1109/TMRB.2024.3408324

Guoqing Li;Jing Li;Gastone Ciuti;Paolo Dario;Qiang Huang

{"title":"Pose-Independent Interaction Distance Adjustment for Magnetically Driven Robotic Capsules","authors":"Guoqing Li;Jing Li;Gastone Ciuti;Paolo Dario;Qiang Huang","doi":"10.1109/TMRB.2024.3408324","DOIUrl":"https://doi.org/10.1109/TMRB.2024.3408324","url":null,"abstract":"Safe capsule-colon interaction for magnetically driven robotic capsules is important in clinical applications. This work presents a solution based on the amplitude information of the magnetic field to adjust the distance between the interacting magnets, in order to prevent the magnetic forces exerted on the capsule robot and the pressure on the intestine walls from being overlarge, which may cause large deformation of the colon. As the first step, the geometry of the internal magnet embedded in the capsule is optimized to approach a near-spherical amplitude of the magnetic field based on the dipole model. Next, mathematical mapping from magnetic field amplitude to the interaction distance between the magnets is presented with constraint derivation and implementation. Then, a strategy to adjust the distance between the interacting magnets is provided based on the mapping using the magnetic field information. Finally, experiments are designed to validate the pose-independent interaction distance adjustment. Compared with the previous work, the proposed solution enables the quick interaction distance adjustment between the magnets to enhance the safety of capsule-colon interaction in the magnetically driven capsule endoscopies, since the interaction distance is derived straightforwardly from the magnetic field signals, without requiring the prerequisite implementation of capsule localization.","PeriodicalId":73318,"journal":{"name":"IEEE transactions on medical robotics and bionics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141965166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Fourier Decomposition-Based Automated Classification of Healthy, COPD, and Asthma Using Single-Channel Lung Sounds 基于傅立叶分解的健康、慢性阻塞性肺病和哮喘的单通道肺音自动分类法

IF 3.4

IEEE transactions on medical robotics and bionics Pub Date : 2024-06-03 DOI: 10.1109/TMRB.2024.3408325

Vaibhav Koshta;Bikesh Kumar Singh;Ajoy K. Behera;Ranganath T. G.

{"title":"Fourier Decomposition-Based Automated Classification of Healthy, COPD, and Asthma Using Single-Channel Lung Sounds","authors":"Vaibhav Koshta;Bikesh Kumar Singh;Ajoy K. Behera;Ranganath T. G.","doi":"10.1109/TMRB.2024.3408325","DOIUrl":"https://doi.org/10.1109/TMRB.2024.3408325","url":null,"abstract":"Subjective discrimination of asthma and Chronic Obstructive Pulmonary Disease (COPD) is challenging as they share overlapping symptoms and are subject to personal interpretation. Hence, there is a demand for an alternative diagnostic system devoid of any subjective interference. The current study introduces Fourier Decomposition Method (FDM) based models utilizing Discrete Cosine Transform (DCT) and Discrete Fourier Transform (DFT) to identify patients with asthma and COPD by analyzing lung sound signals. The signals were decomposed into Fourier intrinsic band functions (FIBF) using three filter banks: dyadic, equal energy, and uniform band. Four statistical attributes, namely: Shannon entropy, log entropy, median absolute deviation and kurtosis, are calculated from relevant FIBF. Support vector machine (SVM), k-nearest neighbor (kNN) and ensemble classifier (EC) optimized with Bayesian optimization are used for classification of asthma vs COPD and normal vs adventitious sound, respectively. The highest accuracies achieved using DCT with 10-fold cross-validation are as follows: 99.4% (Asthma vs COPD), 99.1% (Asthma vs COPD vs Normal), 99.4% (COPD vs Normal) and 99.7% (Asthma vs Normal). Similarly, the highest accuracies reported by DFT with 10-fold cross-validation are: 99.4% (Asthma vs COPD), 99.6% (Asthma vs COPD vs Normal), 99.4% (COPD vs Normal) and 99.8% (Asthma vs Normal).","PeriodicalId":73318,"journal":{"name":"IEEE transactions on medical robotics and bionics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141965687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Bayesian Algorithm-Based Force Profiles Optimization of Hip-Assistive Soft Exosuits Under Variable Walking Speeds 不同步行速度下基于贝叶斯算法的髋关节辅助软外包受力曲线优化设计

IF 3.4

IEEE transactions on medical robotics and bionics Pub Date : 2024-06-03 DOI: 10.1109/TMRB.2024.3408308

Qiang Chen;Jiaxin Wang;Qian Xiang;Shijie Guo

{"title":"Bayesian Algorithm-Based Force Profiles Optimization of Hip-Assistive Soft Exosuits Under Variable Walking Speeds","authors":"Qiang Chen;Jiaxin Wang;Qian Xiang;Shijie Guo","doi":"10.1109/TMRB.2024.3408308","DOIUrl":"https://doi.org/10.1109/TMRB.2024.3408308","url":null,"abstract":"Relevant research highlights humans’ capacity to continuously adapt their walking speed to minimize metabolic energy consumption during overground free walking. Past studies have shown that soft exosuits assisting in hip flexion and extension can reduce metabolic costs and regulate gait parameters during human locomotion. This emphasizes the need to fine-tune hip exosuit parameters to align with walking speed, thereby enhancing metabolic efficiency. This study aims to optimize assistive force parameters of hip exosuits across different walking speeds, providing insights for optimizing force profiles in outdoor walking. We employed a human-in-the-loop approach with Bayesian optimization to determine optimal force profiles for hip assistance. Six subjects performed treadmill walking at four fixed speeds (0.84, 1.16, 1.48, and 1.8 m/s), optimizing control parameters for each speed and establishing a Bayesian experience (BXE) linking walking speed to optimal parameters. Furthermore, we developed a real-time force optimization controller based on the BXE for adjusting the force parameters of assistance. Outdoor walking experiments with the same subjects showed that BXE-optimized profiles significantly reduced metabolic costs compared to fixed profiles. This study underscores the importance of optimizing assistive forces for varying walking speeds in humans.","PeriodicalId":73318,"journal":{"name":"IEEE transactions on medical robotics and bionics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141965684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Design and Evaluation for a Soft Intra-Abdominal Wireless Laparoscope 腹腔内软性无线腹腔镜的设计与评估

IF 3.4

IEEE transactions on medical robotics and bionics Pub Date : 2024-04-18 DOI: 10.1109/TMRB.2024.3391048

Hui Liu;Ning Li;Shuai Li;Gregory J. Mancini;Jindong Tan

{"title":"Design and Evaluation for a Soft Intra-Abdominal Wireless Laparoscope","authors":"Hui Liu;Ning Li;Shuai Li;Gregory J. Mancini;Jindong Tan","doi":"10.1109/TMRB.2024.3391048","DOIUrl":"https://doi.org/10.1109/TMRB.2024.3391048","url":null,"abstract":"In single-incision laparoscopic surgery (SILS), magnetic anchoring and guidance system (MAGS) is a promising technique to prevent clutter in the surgical workspace and provide a larger vision field. Existing camera designs mainly rely on a rigid structure and sliding motion, which may cause stress concentration and tissue damage on curved abdominal walls. Meanwhile, the insertion procedure is also challenging. In this paper, we proposed a wireless MAGS consisting of soft material and wheel structure design. The camera can passively bend and adapt to the curved tissue surface to relieve stress concentration. The wheel structure transfers the sliding motion to rolling motion when the camera tilts and translates, avoiding tissue rupture due to dry friction and facilitating smooth motion. The experiments show the novel laparoscope has dexterous locomotion and bendability with 20° in bending angle and \u0000<inline-formula> <tex-math>$16.4mm$ </tex-math></inline-formula>\u0000 in displacement. The maximum stress is reduced by 64% compared with rigid designs. An easy and safe insertion procedure based on soft property is also introduced, which takes less than 2 minutes on average without the assistance of additional instruments.","PeriodicalId":73318,"journal":{"name":"IEEE transactions on medical robotics and bionics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141965168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Pneumatic Driven MRI-Guided Robot System for Prostate Interventions 用于前列腺介入治疗的气动驱动核磁共振成像引导机器人系统

IF 3.4

IEEE transactions on medical robotics and bionics Pub Date : 2024-04-16 DOI: 10.1109/TMRB.2024.3389490

Haipeng Liang;Wanli Zuo;Dimitri Kessler;Tristan Barrett;Zion Tsz Ho Tse

引用次数: 0

Toward Automatic Stomach Screening Using a Wireless Magnetically Actuated Capsule Endoscope 利用无线磁控胶囊内窥镜实现胃部自动筛查

IEEE transactions on medical robotics and bionics Pub Date : 2024-04-10 DOI: 10.1109/TMRB.2024.3387040

Heng Zhang;Yehui Li;Xinfa Shi;Yichong Sun;Jixiu Li;Yisen Huang;Wing Yin Ng;Chengxiang Liu;Philip Wai Yan Chiu;Chi-Kwan Lee;Zheng Li

{"title":"Toward Automatic Stomach Screening Using a Wireless Magnetically Actuated Capsule Endoscope","authors":"Heng Zhang;Yehui Li;Xinfa Shi;Yichong Sun;Jixiu Li;Yisen Huang;Wing Yin Ng;Chengxiang Liu;Philip Wai Yan Chiu;Chi-Kwan Lee;Zheng Li","doi":"10.1109/TMRB.2024.3387040","DOIUrl":"https://doi.org/10.1109/TMRB.2024.3387040","url":null,"abstract":"Stomach cancer remains one of the primary health challenges with a high incidence and motility. Magnetically actuated capsule endoscope (MACE) provides a noninvasive and practical solution for stomach screening, due to its contactless actuation and high maneuverability. In this work, with an aim of shortening procedure duration and lowering surgeon workload, we propose an automatic stomach screening strategy by using a MACE to automatically detect and capture specific gastric features for mapping the whole stomach. To achieve this, an electromagnetic actuation system and a wireless MACE with real-time video transmission and orientation feedback are developed. Magnetic actuation modeling and kinematics analysis of the MACE are conducted, based on which an optimization-based position controller and a visual-servo-based orientation controller are designed. Simulative and experimental validation are conducted for proof-of-concept, with attractive results showing that the MACE can be accurately and stably controlled with a mean absolute position error of around 2.56 mm and an average convergent time of about 1.1 s for visual servoing and that automatic stomach screening is successfully demonstrated in a stomach phantom. The proposed stomach screening strategy using a MACE indicates high potential in clinical practice.","PeriodicalId":73318,"journal":{"name":"IEEE transactions on medical robotics and bionics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140820245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

daVinci Research Kit Patient Side Manipulator Dynamic Model Using Augmented Lagrangian Particle Swarm Optimization 利用增强拉格朗日粒子群优化技术建立达芬奇研究套件病人侧机械手动态模型

IEEE transactions on medical robotics and bionics Pub Date : 2024-04-10 DOI: 10.1109/TMRB.2024.3387070

Omer Faruk Argin;Rocco Moccia;Cristina Iacono;Fanny Ficuciello

{"title":"daVinci Research Kit Patient Side Manipulator Dynamic Model Using Augmented Lagrangian Particle Swarm Optimization","authors":"Omer Faruk Argin;Rocco Moccia;Cristina Iacono;Fanny Ficuciello","doi":"10.1109/TMRB.2024.3387070","DOIUrl":"https://doi.org/10.1109/TMRB.2024.3387070","url":null,"abstract":"In surgical robotics, accurate characterization of the dynamic model is crucial. It serves as a foundation for developing robust control algorithms that effectively handle the complex dynamics of the robot and its interactions with the environment. Additionally, an accurate dynamic model aids in estimating external forces and disturbances, enhancing the safety and stability of the control. Among surgical robots, the da Vinci Research Kit (dVRK) is one of the most used, and it has been a crucial instrument in removing a barrier to entry for new research groups in surgical robotics by facilitating the development of improved control algorithms. This paper presents a method for dynamic model identification of the dVRK *psm robot that employs a novel friction model definition. The model formulation has been modified by including the Stribeck effect at low velocities, and the friction has been estimated using the superposition method. The dynamic parameters are identified utilizing a restricted optimization method with physical consistency requirements in an Augmented Lagrangian Particle Swarm Algorithm (ALPSO) methodology. The identified model is thoroughly evaluated, and the results are compared with existing literature methods. Also, a model-based sensorless force estimation method was used to test the dynamic model.","PeriodicalId":73318,"journal":{"name":"IEEE transactions on medical robotics and bionics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140820396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Design, Modeling and Optimization of a Magnetic Resonance Conditional 3-RRR Spherical Parallel Robot for Neurosurgery 用于神经外科手术的磁共振条件 3-RRR 球形并行机器人的设计、建模和优化

IEEE transactions on medical robotics and bionics Pub Date : 2024-04-10 DOI: 10.1109/TMRB.2024.3387114

Yanding Qin;Yueyang Shi;Longxin Wang;Hongpeng Wang;Jianda Han

{"title":"Design, Modeling and Optimization of a Magnetic Resonance Conditional 3-RRR Spherical Parallel Robot for Neurosurgery","authors":"Yanding Qin;Yueyang Shi;Longxin Wang;Hongpeng Wang;Jianda Han","doi":"10.1109/TMRB.2024.3387114","DOIUrl":"https://doi.org/10.1109/TMRB.2024.3387114","url":null,"abstract":"In neurosurgery, magnetic resonance (MR) imaging is extensively utilized for preoperative diagnosis and postoperative evaluation due to its superior soft tissue contrast. However, the strong magnetic field poses a challenge to the real-time utilization of MR for intraoperative navigation. To facilitate neurosurgery in the MR environment, this paper develops a MR conditional robot featuring nonferrous materials and ultrasonic motor actuation. The robot consists of a 3-degree-of-freedom (3-DOF) translational module and a 3-DOF remote center of motion (RCM) module. The RCM module incorporates a 3-RRR spherical parallel mechanism. The mechanical design and kinematic modeling of the RCM module is completed. This paper further conducts the optimization for the RCM module. Additionally, a path-planning algorithm, focusing on the maximization of dexterity, is introduced, and the feasible workspace of the optimized RCM module is evaluated. A prototype is fabricated, and the orientation repeatability of the RCM module is measured to be 0.055±0.0016°, and the absolute orientation error is 2.05±0.019°. Needle insertion experiments are performed on an agarose phantom to evaluate the feasibility of the robot. The impact on signal-to-noise ratio in MRI images caused by the robot is less than 4%, indicating a highly promising applicability in MR conditional neurosurgery.","PeriodicalId":73318,"journal":{"name":"IEEE transactions on medical robotics and bionics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140820254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development of a Robotic Ultrasound System to Assist Ultrasound Examination of Pregnant Women 开发辅助孕妇超声波检查的机器人超声波系统

IF 3.4

IEEE transactions on medical robotics and bionics Pub Date : 2024-04-10 DOI: 10.1109/TMRB.2024.3387047

Maria Bamaarouf;Flavien Paccot;Laurent Sarry;Hélène Chanal

{"title":"Development of a Robotic Ultrasound System to Assist Ultrasound Examination of Pregnant Women","authors":"Maria Bamaarouf;Flavien Paccot;Laurent Sarry;Hélène Chanal","doi":"10.1109/TMRB.2024.3387047","DOIUrl":"https://doi.org/10.1109/TMRB.2024.3387047","url":null,"abstract":"This research paper centers on addressing a common issue faced by clinicians during ultrasound examinations, namely work-related musculoskeletal disorders (WRMSDs). The implementation of robotic ultrasound has the potential to reduce these disorders using teleoperated assistance, collaborative support, or even autonomous systems. In this study, we introduce a new collaborative assisting system specifically designed for ultrasound examinations involving pregnant, obese patients. The primary objective is to devise a transparent co-manipulation strategy that enables clinicians to maintain their natural gestures during the procedure. The key principle behind this approach is to ensure that the robot functions as a helpful tool without interfering with the examination process. To achieve this, a novel co-manipulation control strategy is developed, which involves the computation of a virtual solid’s path based on the operator’s interaction. This approach presents numerous benefits in comparison to conventional control techniques. It demonstrates improvements in terms of accuracy, diminishes task execution time, facilitates a more intuitive parameter adjustment process, and necessitates less exertion of force by the operator. Consequently, it could potentially serve as a viable solution for addressing the challenges faced by sonographers. Hence, the potential benefit of this new co-manipulation method is demonstrated experimentally by comparison with impedance and active compliance control strategies.","PeriodicalId":73318,"journal":{"name":"IEEE transactions on medical robotics and bionics","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141965837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0