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Electromagnetic fields, Antennas (Electronics), Wireless sensor networks, and Rapid prototyping

Keywords: metallization; radio frequency performance; SLA reflector; three-dimensional printed Abstract A novel high precision and lightweight reflector antenna is proposed. The fabrication process of the reflector adopted Stereo Lithography Apparatus (SLA) printed and metallization. The proposed SLA Reflector (SLAR) antenna structure adopts three-dimensional-printed, which can design complex geometric shapes flexibly and rapid prototyping. That is a good substitute for the traditional method of millimeter wave reflector processing. In order to realize radio frequency (RF) characteristics perfectly, the metallization process of photosensitive resin was elaborated, which realized by first electroless nickel plating, then copper electroplating, and finally chromium electroplating on the protective layer. For verification, the designed reflector antenna was manufactured and measured. The reflectivity of SLAR was measured well by the bow method, which validates excellent fabrication accuracy and reliability. The gain and pattern were measured in the anechoic chamber. The results show that the proposed reflector antenna achieves the gain of 25dBi and the 3dB gain bandwidth of 43% over the full Ka-band. A good agreement can be observed between measurement and simulation. Biographical information: Liwei Guo received the B.E. degree in from the Guilin University of Electronic Technology, Guilin, China in 2006. She is currently pursuing the PhD degree in Guilin University of Electronic Technology, Guilin, China. Her current research interests include metasurfaces, millimeter-wave reflector antenna. Simin Li received the B.S. degree in wireless communication engineering from Nanjing University of Posts and Telecommunications, Nanjing, China, in 1984, and the M.S. and PhD degrees in electronics engineering from the University of Electronic Science and Technology of China, Chengdu, China, in 1989 and 2007, respectively. Dr. Li is currently the President and a Professor with Guangxi University of Science and Technology, Liuzhou, China. His current research interests include the design of electrically small antennas, antenna arrays for high-frequency communication systems, and wireless sensor networks. Xing Jiang received the Master's degree in electromagnetic field and microwave technology from Beijing Institute of Technology, Beijing, China, in 1986. Since 2000, she has been a Professor with the Guilin University of Electronic Technology, Guilin, China. She was sponsored by the National Natural Science Foundation of China and the Natural Science Foundation of Guangxi. Her research interests include smart communication system design, conformal antenna array, and bioelectromagnetics. Xin Liao received the B.E. degree from Chongqing University of Posts and Telecommunications, Chongqing, China, in 1990. He is currently a Lecturer with the Guilin University of Electronic Technology, Guilin, China. His research interests include Electromagnetic Compatibility and antenna measurement. Ying Zhang received the B.E. degree in Harbin Institute of Technology of optical instrument. Now she is a researcher at Beijing Simulation Center. Her research interest is the simulation of visible light/infrared guidance and control systems. Bin Shi is an associate researcher- in Beijing Simulation Center. Her research interest is the simulation of radio frequency target accuracy. Article Note: Funding information Guangxi Innovation Driven Development Special Fund Project, Grant/Award Number: GUIKEAA19254012; Innovation Project of Guangxi Graduate Education, Grant/Award Number: YCBZ2019051; National Natural Science Foundation of China, Grant/Award Numbers: 61761012, 61661011 Byline: Liwei Guo, Simin Li, Xing Jiang, Xin Liao, Ying Zhang, Bin Shi

Algorithm, Sensors -- Analysis, Wireless sensor networks -- Analysis, and Algorithms -- Analysis

Keywords Tissue P System; Wireless Sensor Network; Multi-Objective problem; Task Assignment; Decision Support System; Parallel computing; Sustainable computing Abstract The contemporary wireless sensor applications employ a Heterogeneous Wireless Sensor Network (HeWSN) to achieve its multi-objective missions. Modern wireless nodes constituting the HeWSN are more versatile in terms of its capabilities, functionalities, and applications. Assigning tasks in a dynamic HeWSN environment are challenging due to its inherent heterogeneous properties and capabilities. The investigation of existing task assignment algorithms reveals (i) the majority of the existing task assignment algorithms were designed for the homogeneous environment, (ii) most of the nature-inspired algorithms were built for centralized architecture. Scheduling tasks by existing task assignment algorithms lead to underutilization of resources as well as to the rapid depletion of network resources. To this end, a novel, distributed, heterogeneous task assignment algorithm adhering the modern sensors capabilities, functionalities and sensor application to attain sustainable computing is required. Based on the investigation, Tissue P-System inspired task assignment algorithm for the distributed heterogeneous WSN has been modelled. The experimental analyses of the proposed method have been self-evaluated as well as compared with the corresponding recent benchmark algorithms under various conditions and its performance metrics are analysed. Author Affiliation: Karunya Institute of Technology & Sciences, Coimbatore, Tamil Nadu 641 114, India * Corresponding author. Article History: Received 18 November 2019; Revised 11 June 2020; Accepted 21 June 2020 (footnote) Peer review under responsibility of King Saud University. Byline: Titus Issac [titusissac@gmail.com] (*), Salaja Silas, Elijah Blessing Rajsingh

3D printing -- Case studies, Engineering schools -- Case studies, Labor market -- Case studies, and Mechanical engineering -- Case studies

Keywords: 3D digitizing; design skills; hands-on activities; redesign; reverse engineering Abstract Today's job market is seeking engineers with competencies to design innovative solutions that meet sophisticated customer needs. Engineering education is then challenged to equip future engineers with holistic engineering design skills, especially functional ones. A powerful means to strengthen these skills is the use of reverse-engineering-based activities, which consist of examining, extracting information, and redesigning existing products. However, most current education endeavours, based on reverse engineering, consist only of practicing simple teardowns that have circumscribed impact on the acquisition of skills. Therefore, there is a need for more elaborated authentic hands-on activities to gain a broad set of design skills. This study addresses this gap by the development of a concept of wide-ranging engineering activities that start with the study of an existing product and ends with an improved redesigned three-dimensional (3D) printed product. This concept of activities was developed to strengthen a conventional course on product design. Thus, a tailored comprehensive redesign process is proposed first, and expanded as a concept of a set of experiential activities, with associated measures for skills acquisition. This concept encompasses teardown, 3D digitizing and rapid prototyping, and aims mainly at facilitating the understanding of components' functionalities, the numerical reconstruction by 3D digitizing, the mechanical modelling and engineering analysis of parts and finally the 3D printing of the redesign output. To understand, experience, and weigh up the relevance of the proposed concept of activities, a preliminary implementation, and a case study are illustrated. Particularly, the relevance of the concept is demonstrated through the assessment of the activities' measures. In short, this study provides educators with an authentic education tool that leverages on a broader reverse engineering vision to boost the job's sought-after design skills. Byline: Mohammed Akerdad, Ahmed Aboutajeddine, Mohammed Elmajdoubi

Program errors -- Analysis, Executives -- Analysis, and Computer science -- Analysis

Keywords Concolic testing; Virtual prototyping; SystemC; RISC-V; Internet of things Abstract Constrained Internet of Things (IoT) devices with limited computing resource are increasingly employed in security critical areas. Therefore, it is important for the firmware of these devices to be tested sufficiently. On non-constrained conventional devices, dynamic testing techniques (e.g. fuzzing, symbolic execution, or concolic testing) are successfully utilized to discover critical bugs in tested software. Unfortunately, the diverse ecosystem and the dependence on low-level details of a wide range of peripherals makes it difficult to use these techniques in the IoT context. In order to address these challenges, we present SymEx-VP an open source emulation-based approach for concolic testing of IoT firmware. SymEx-VP is a virtual prototype for RISC-V hardware platforms and allows concolic testing of RISC-V machine code. To support a wide range of different peripherals, SymEx-VP utilizes SystemC, a hardware modeling language for C++. By employing a SystemC extension mechanism, SymEx-VP can inject concolic inputs into the emulated firmware through the memory-mapped I/O peripheral interface of existing SystemC peripheral models. This allows us to support different operating systems and libraries used in the IoT with minimal integration effort. We provide an extensive description of SymEx-VP, illustrate peripheral modeling and firmware testing using it by example, and perform tests with four operating systems to demonstrate the advantages of our OS-agnostic firmware testing method. Author Affiliation: (a) Institute of Computer Science, University of Bremen, Bremen, Germany (b) Cyber-Physical Systems, DFKI GmbH, Bremen, Germany * Corresponding author. Article History: Received 21 December 2021; Revised 25 February 2022; Accepted 2 March 2022 (footnote) The code (and data) in this article has been certified as Reproducible by Code Ocean: (https://codeocean.com/). More information on the Reproducibility Badge Initiative is available at https://www.elsevier.com/physical-sciences-and-engineering/computer-science/journals. (footnote)[white star] This work was supported in part by the German Federal Ministry of Education and Research (BMBF) within the poject Scale4Edge under contract no. 16ME0127 and within the project VerSys under contract no. 01IW19001. Byline: Sören Tempel [tempel@uni-bremen.de] (a,*), Vladimir Herdt [vherdt@uni-bremen.de] (a,b), Rolf Drechsler [drechsler@uni-bremen.de] (a,b)