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J. Comput. Inf. Sci. Eng. 2019;19(2):021001-021001-14. doi:10.1115/1.4041969.

The accumulated error and noise sensitivity are the two common problems of ordinary inertial sensors. An accurate gyroscope is too expensive, which is not normally applicable in low-cost missions of mobile robots. Since the accelerometers are rather cheaper than similar types of gyroscopes, using redundant accelerometers could be considered as an alternative. This mechanism is called gyroscope-free navigation. The article deals with autonomous mobile robot (AMR) navigation based on gyroscope-free method. In this research, the navigation errors of the gyroscope-free method in long-time missions are demonstrated. To compensate the position error, the aid information of low-cost stereo cameras and a topological map of the workspace are employed in the navigation system. After precise sensor calibration, an amendment algorithm is presented to fuse the measurement of gyroscope-free inertial measurement unit (GFIMU) and stereo camera observations. The advantages and comparisons of vision aid navigation and gyroscope-free navigation of mobile robots will be also discussed. The experimental results show the increasing accuracy in vision-aid navigation of mobile robot.

Commentary by Dr. Valentin Fuster
J. Comput. Inf. Sci. Eng. 2019;19(2):021002-021002-7. doi:10.1115/1.4042102.
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This paper presents an experimental cloud service framework for design evaluation of personalized footwear in augmented reality (AR) via networks. The service allows users to ubiquitously perceive themselves trying on three-dimensional (3D) shoe models in a video stream. They upload a clip of feet motion recorded by a commercial depth camera to the cloud. A new clip is generated to display the try-on process and made available to specified receivers via video streaming on a mobile device. The framework design emphasizes making most use of open-source software and off-the-shelf technologies commercially available. A prototyping cloud system implementing the framework demonstrates the practical value of virtual footwear try-on as AR as a service (ARaaS). This experimental study realizes the idea of human-centric design evaluation in modern e-commerce. The cloud framework may provide a feasible example to improve the usability for real-time applications of AR.

Commentary by Dr. Valentin Fuster
J. Comput. Inf. Sci. Eng. 2019;19(2):021003-021003-9. doi:10.1115/1.4042104.

Manufacturing companies maintain manufacturing knowledge primarily as unstructured text. To facilitate formal use of such knowledge, previous efforts have utilized natural language processing (NLP) to classify manufacturing documents or extract manufacturing concepts/relations. However, extracting more complex knowledge, such as manufacturing rules, has been evasive due to the lack of methods to resolve ambiguities. Specifically, standard NLP techniques do not address domain-specific ambiguities that are due to manufacturing-specific meanings implicit in the text. To address this important gap, we propose an ambiguity resolution method that utilizes domain ontology as the mechanism to incorporate the domain context. We demonstrate its feasibility by extending our previously implemented manufacturing rule extraction framework. The effectiveness of the method is demonstrated by resolving all the domain-specific ambiguities in the dataset and an improvement in correct detection of rules to 70% (increased by about 13%). We expect that this work will contribute to the adoption of semantics-based technology in manufacturing field, by enabling the extraction of precise formal knowledge from text.

Commentary by Dr. Valentin Fuster
J. Comput. Inf. Sci. Eng. 2019;19(2):021004-021004-10. doi:10.1115/1.4042325.

Synthesizing circuit-, branch-, or order-defects-free planar four-bar mechanism for the motion generation problem has proven to be a difficult problem. These defects render synthesized mechanisms useless to machine designers. Such defects arise from the artificial constraints of formulating the problem as a discrete precision position problem and limitations of the methods, which ignore the continuity information in the input. In this paper, we bring together diverse fields of pattern recognition, machine learning, artificial neural network, and computational kinematics to present a novel approach that solves this problem both efficiently and effectively. At the heart of this approach lies an objective function, which compares the motion as a whole thereby capturing designer's intent. In contrast to widely used structural error or loop-closure equation-based error functions, which convolute the optimization by considering shape, size, position, and orientation of the given task simultaneously, this objective function computes motion difference in a form, which is invariant to similarity transformations. We employ auto-encoder neural networks to create a compact and clustered database of invariant motions of known defect-free linkages, which serve as a good initial choice for further optimization. In spite of highly nonlinear parameters space, our approach discovers a wide pool of defect-free solutions very quickly. We show that by employing proven machine learning techniques, this work could have far-reaching consequences to creating a multitude of useful and creative conceptual design solutions for mechanism synthesis problems, which go beyond planar four-bar linkages.

Commentary by Dr. Valentin Fuster
J. Comput. Inf. Sci. Eng. 2019;19(2):021005-021005-13. doi:10.1115/1.4041970.

Computer-aided inspection planning (CAIP) has gained significant research attention in the last years. So far, most CAIP systems have focused on the use of a touch probe mounted on a coordinate measuring machine (CMM). This article investigates multisensor measurement aiming to perform automatic and efficient inspection plans. High-level inspection planning, which deals with sequencing of measuring operations, is the main concern of inspection planning. This paper presents an automatic approach to generate inspection sequences by combining laser sensor and touch probe, and by giving preference to the measurement using the laser sensor if quality requirements are satisfied. The proposed approach consists of three steps. In the first step, recognition of inspection data from the computer-aided design (CAD) part model is carried out based on the concept of inspection feature (IF), and the extracted information is stored in a database. In the second step, a list of privileged scanner orientations is proposed by analyzing the accessibility of both sensors. In the third step, a sequence of operations is generated iteratively. For a given scanner orientation, the ability of the laser sensor is assessed according to an original process based on fuzzy logic model. If the laser sensor does not meet the ability requirements, touch probe ability is assessed. The proposed approach is implemented and tested on a part defined by its CAD model and specifications.

Commentary by Dr. Valentin Fuster
J. Comput. Inf. Sci. Eng. 2019;19(2):021006-021006-6. doi:10.1115/1.4042326.

Finite element analysis was used to investigate the responses of five adult degenerative scoliosis (ADS) subjects to cyclic vibration before and after surgical alignment (SA). The dynamic responses of the healthy and presurgical scoliotic spines to the sinusoidal cyclic vibrations have been investigated in previous studies by computational and experimental approaches. However, no computational or experimental results were available for the pre- and postsurgical scoliosis subjects. The effect of the SA on the vibrational response of the postsurgical scoliosis subjects remained unknown. The objective of this study was to compare differences of the dynamic responses to the cyclic vibration input among the scoliotic spines for pre- and post-SA. Previous studies suggested that untreated scoliotic spines especially at the apical vertebrae are more sensitive to the vibration than spinal segments with normal anatomies. Results of this study showed that the SA was able to reduce the vibrational response of the scoliotic spines to the whole body vibrations (WBV) at the fused level while not significantly increase the response at the superior adjacent level, which suggested that SA is able to reduce the risk of further degeneration in the scoliotic spines.

Commentary by Dr. Valentin Fuster
J. Comput. Inf. Sci. Eng. 2019;19(2):021007. doi:10.1115/1.4041744.

The goal of this research is to optimize an object's macroscopic topology and localized gradient material properties (GMPs) subject to multiple loading conditions simultaneously. The gradient material of each macroscopic cell is modeled as an orthotropic material where the elastic moduli in two local orthogonal directions we call x and y can change. Furthermore, the direction of the local coordinate system can be rotated to align with the loading conditions on each cell. This orthotropic material is similar to a fiber-reinforced material where the number of fibers in the local x and y-directions can change for each cell, and the directions can as well be rotated. Repeating cellular unit cells, which form a mesostructure, can also achieve these customized orthotropic material properties. Homogenization theory allows calculating the macroscopic averaged bulk properties of these cellular materials. By combining topology optimization with gradient material optimization and fiber orientation optimization, the proposed algorithm significantly decreases the objective, which is to minimize the strain energy of the object subject to multiple loading conditions. Additive manufacturing (AM) techniques enable the fabrication of these designs by selectively placing reinforcing fibers or by printing different mesostructures in each region of the design. This work shows a comparison of simple topology optimization, topology optimization with isotropic gradient materials, and topology optimization with orthotropic gradient materials. Finally, a trade-off experiment shows how different optimization parameters, which affect the range of gradient materials used in the design, have an impact on the final objective value of the design. The algorithm presented in this paper offers new insight into how to best take advantage of new AM capabilities to print objects with gradient customizable material properties.

Commentary by Dr. Valentin Fuster

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