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Robotic devices can be leveraged to raise the abilities of humans to perform demanding and complex tasks with less effort. Although the first priority of such human–robot interaction (HRI) is safety, robotic devices must also be intuitive and efficient in order to be adopted by a broad range of users. One challenge in the control of such assistive robots is the management of the end-effector orientation, that is not always intuitive for the human operator, especially for neophytes. This paper presents a novel orientation control algorithm designed for robotic arms in the context of HRI. This paper aims at making the control of the robot's orientation easier and more intuitive for the user, both in the fields of rehabilitation (in particular individuals living with upper limb disabilities) and industrial robotics. The performance and intuitiveness of the proposed orientation control algorithm is assessed and improved through two experiments with a JACO assistive robot with 25 able-bodied subjects, an online survey with 117 respondents via the Amazon Mechanical Turk and through two experiments with a UR5 industrial robot with 12 able-bodied subjects.

Carya tonkinensis Lecomte is a multipurpose tree species, naturally distributing in India, China, and Vietnam. Extract from leaves of C. tonkinensis contains pinostrobin acting as anti-bacteria and anti-infection. It is used as traditional medicine. Seeds are edible and contain oil. In addition, seed cover can be used to produce activated charcoal. Therefore, growing C. tonkinensis may contribute to poverty reduction in mountainous areas. This study aims to analyze suitable planting method and density for growing C. tonkinensis in Son La province, Northwestern Vietnam. Three treatments in planting method were considered: mixed planting of C. tonkinensis and Chukrasia tabularis, pure planting and scattered planting. Four treatments in planting density were considered: 625 plants/ha, 830 plants/ha, 1,000 plants/ha and 1,100 plants/ha. Stem height and stump diameter (Do) were measured at one year after planting, and death trees were counted for survival rate. The results indicated that scattered planting is the most suitable for C. tonkinensis and pure planting could also be applied. Meanwhile, planting density of 625 plants/ha (spacing of 4 × 4 m) and 830 plants/ha (spacing of 3 × 4 m) achieved the best performance. In both planting densities, the survival rate of the plants achieved >90%, their growths were >80 cm in height and >0.8 cm in Do after planting one year. It is recommended that site preparation should be conducted by cutting bands of 2 m width and un-cutting bands of 2 m. In addition, seedlings of >1-year old, which are taller than 0.6 m, should be used to ensure higher survival and growths of plants.

Cycle time reduction is one way to increase the energy efficiency of the injection molding production process. For injection molding, conformal cooling channels can be considered as a potential solution for obtaining a uniform temperature distribution in the mold, which results in a shorter cooling time and better quality of the molded part. However, the design and manufacture of optimal cooling channels is a challenge due to their complex geometry and heat transfer. This paper presents a method to maximize the efficiency of a conformal cooling channel made by 3D printing technology. The combination of analytical formulas and CAE simulation is applied to design optimal cooling channels in terms of cooling efficiency and manufacturability. An actual case study is introduced and analyzed to demonstrate the benefit of the conformal cooling channel and the robustness of the proposed design method. The results show that the cooling time and cycle time can be reduced more than 50% when molding a plastic product that is difficult to cool by conventional straight-drilled cooling channels. This is a great contribution to an environmentally friendly manufacturing technology.

Supervisor:西村 俊, 先端科学技術研究科, 博士

International audience; The aim of this paper is to propose an effective method to create and store data of lattice structureCAD models. The currently used computer-aided design (CAD) tools are unsuitable for creating lattice structures because of the large number of facets in the lattice structure CAD models. Therefore, a new solution is required to overcome this problem. In this study a new skeleton model to create and store lattice structures is proposed. The skeleton model consists of the basic elements used to describe a lattice structure model: points, lines, joints, and sections. The configurations necessary to describe the lattice structures and the newly developed algorithm for the skeleton model generation of these configurations are described. To illustrate its application, a case study to create conformal and non-conformal lattice structures by using the newly developed skeleton model was presented. Unlike current techniques, this proposed method does not need to create boundary representations of the lattice structure CAD models and enables the computer to represent and store lattice structure model data more efficiently. The findings of this research have wide applicability in the development of CAD software and file formats tailored for additive manufacturing.

The appearance of Additive Manufacturing (AM) technologies has brought many benefits for industry as well as other areas of life: architecture, medical, etc. In order to create a part by AM technologies especially with EBM technology, it has to go through many steps: designing parts in CAD environment, applying CAM operations, printing the parts and post-print process. Analyzing parts to decide if it is necessary to add the support structures play an important role because of their effects on the quality of the finishing parts. To assess the printability of part, feature recognition is a technique that helps make sure all the features of a part will not exhibit defects before the printing process. There are different studies on how to recognize features after design. Several research groups have developed systems to analyze the characteristics of parts but there are very few systems to analyze parts for the AM process. Therefore, it is necessary to propose a tool to help to perform the feature recognition process in AM technologies. A simple interface presented in the paper has been developed in C++ programming language based on the Open Cascade Technology software to help users automatically recognizing some features of a model. It is applied to a recurrent problem related to support removability. A new type of feature called surface with potential support difficult to remove is defined.

Background Postherpetic neuralgia (PHN) is the most common and bearable complication of herpes zoster (HZ). This pain may have negative impact on the patient's all aspects of daily life and health‐related quality of life (HRQOL). Despite numerous advances in treatment, many patients remain resistant to the current therapy options. It is the first time subcutaneous injection of methylprednisolone acetate and lidocaine has been used to treat refractory PHN. We report the results of this treatment evaluating pain relief and HRQOL improvement in this disorder. Methods A total of 43 patients with refractory PHN was enrolled in the observational study. All patients received daily subcutaneous injection of methylprednisolone acetate and lidocaine for 10 consecutive days. The severity of pain was assessed by using Visual Analog Scale (VAS), and 36‐Item Short Form Survey (SF‐36) was applied to evaluate HRQOL. Assessment of the pain and HRQOL was carried out at baseline and posttreatment at 4 weeks as well as 6 and 12 months. Results At baseline, all patients experienced severe PHN with average VAS scores of 8.44 ± 0.85 (minimum 7; maximum 10). At 4 weeks, 6 months, and 12 months after treatment, the pain had significantly decreased (P

Delta robot is a kind of parallel robot that is widely used in industrial applications for its impressive advantages compared to the serial robot such as fast-moving speed and great productivity assembly. It is very useful for classification products and assembly requiring high processing speed. Saving materials and costs during the design and manufacturing process while ensuring the working capabilities of robots such as stiffness and durability is very important. Therefore, the authors propose an approach of utilizing the topology optimization method in the design process to solve such a problem. In this paper, the process of studying and applying the topology optimization method to design the Delta robot arm is presented. The redesigned product has a lighter weight, consumes less material, and therefore has lower manufacturing costs but still ensures the mechanical properties and the working ability requirement.

Machine learning approaches using intravascular optical coherence tomography (OCT) to predict fractional flow reserve (FFR) have not been investigated. Both OCT and FFR data were obtained for left anterior descending artery lesions in 125 patients. Training and testing groups were partitioned in the ratio of 5:1. The OCT-based machine learning-FFR was derived for the testing group and compared with wire-based FFR in terms of ischemia diagnosis (FFR ≤ 0.8). The OCT-based machine learning-FFR showed good correlation (r = 0.853, P

The compressive strength is one of the most important properties of concrete, and it is the most controlled parameter during quality control. Many scientists have studied the application of ultrasonic pulse velocity (UPV) to assess concrete quality for decades, due to its distinct advantages compared to conventional compression measurements. The use of fly ash, a by-product of thermal power plants, as one of the component materials in concrete production, replacing certain portions of cement, is one of the important solutions to reduce environmental pollution. The supplementary fly ash will affect the mechanical properties of concrete, especially its compressive strength. The paper proposes a method that allows us to predict the concrete compressive strength when changing its mixture parameters and fly ash content based on ultrasonic pulse velocity. The materials for preparing the specimens are available in Central Vietnam and fly ash is used as partial replacement of cement. Thus, this study contributes to the handling of fly ash from thermal power plants in order to protect the environment for sustainable development in the future.

International audience; his work deals with the numerical modeling of buckling and post-buckling of thin frame structures using a newly developed Timoshenko beam-SPH model. Modeling of thin flexible structures using the 3D continuum SPH [1] formulation is not convenient, since several particles need to be used through the cross section, which results in an excessive increase of computational CPU time. A new extension of the Lagrangian Smoothed Particle Hydrodynamics (SPH) method has been introduced [2] to develop a geometrically nonlinear beam-SPH formulation valid for large displacements and rotations.This is an improvement of the standard stabilized SPH [1] commonly used for continua, in the framework of Timoshenko beam theory, for the modeling of thick frame structures by using only one layer of particles in the beam mid-curve [3]. The proposed new Timoshenko beam-SPH model is efficient and very fast compared to the standard continuum SPH model. The Total Lagrangian Formulation valid for large deformations was adopted using a strong formulation of the differential equilibrium equations based on the principle of collocation.The resulting nonlinear dynamic problem was solved incrementally using the Newmark time integration scheme, commonly used for structural dynamics applications. To validate the reliability and accuracy of the proposed Timoshenko beam-SPH model in solving buckling and post-buckling of frame structure problems, several numerical applications were solved and the results were compared with reference solutions from the literature or obtained using ABAQUS code.

The International Society of Biomechanics (ISB) has proposed standardized recommendations for recording human joint motion. The Euler angles—the orientation representation currently proposed by the ISB—have two drawbacks, namely, the issue of singularities (gimbal lock) and the difficulty to obtain clinical and interpretable orientation representation for compound movements. The orientation representation of the shoulder joint with the Euler angles is particularly challenging due to its broad range of motion. This paper proposes and evaluates an alternative orientation representation for shoulder movement based on the tilt-and-torsion representation, a method that aims at providing a more clinically interpretable solution for describing joint movements compared to the standard Euler angles. Three studies were performed to compare the different orientation representation methods. The first two studies consist in simulations of arm elevation in different planes. The third study is an experiment using inertial-measurement-units with one test subject performing shoulder elevation movements in different planes. The tilt-and-torsion representation is then compared with different Euler angle conventions. The results show that Euler angles are biased or clinically uninterpretable for compound movements. Conversely, tilt-and-torsion representation does not suffer from these limitations. Although not extensive, the experiments suggest that the tilt-and-torsion representation has the potential to better represent human movements and provide more clinically interpretable results than the Euler angles.

Using hand gestures is a natural method of interaction between humans and computers. We use gestures to express meaning and thoughts in our everyday conversations. Gesture-based interfaces are used in many applications in a variety of fields, such as smartphones, televisions (TVs), video gaming, and so on. With advancements in technology, hand gesture recognition is becoming an increasingly promising and attractive technique in human&ndash, computer interaction. In this paper, we propose a novel method for fingertip detection and hand gesture recognition in real-time using an RGB-D camera and a 3D convolution neural network (3DCNN). This system can accurately and robustly extract fingertip locations and recognize gestures in real-time. We demonstrate the accurateness and robustness of the interface by evaluating hand gesture recognition across a variety of gestures. In addition, we develop a tool to manipulate computer programs to show the possibility of using hand gesture recognition. The experimental results showed that our system has a high level of accuracy of hand gesture recognition. This is thus considered to be a good approach to a gesture-based interface for human&ndash, computer interaction by hand in the future.

The cleaning gas stream in a selective laser melting process is a crucial factor that functions to remove condensate and prevent oxidation during fusing. This study investigated the ejected powder ...

This paper presents a new algorithm to classify the multiple stages of sleeping. In this algorithm, the novel feature vector in the time domain is proposed. Various machine learning models were utilized to classify sleeping problems in four categories. The results of this research outperform previous studies and shows high potential in real-time application.

A portfolio can bee seen as an organized presentation of a student's work. Recently, the assignment of digital portfolios has become popular among university faculty; and for some classes, students are required to create a webpage with the descriptions of their work. While this approach allows a student to quickly get started on building his or her portfolio, the amount of work and the complexity of building such an online portfolio can be discouraging; thus, many students do not update them beyond the scope of their current class. Furthermore, not all types of assignments can easily be presented on the web. For example, quizzes and exams are usually available only as hard copies; so students must take additional steps, such as scanning, to include them in their digital portfolios. Thus, most such web pages only include descriptions of students' works or links to an html page which students have created as part of their assignments. In this paper, I will present a convenient way for students to build up their portfolio. By using the techniques outlined in this paper, students will no longer have to be experts in web design to construct a presentable digital portfolio of their class work. Instead, the class work will automatically be converted to a digital format before being returned to the students. Furthermore, I have created a Rich Internet Application that allows students to quickly and conveniently view and manage their portfolios.