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The latest advancements in digital and computational technologies are increasingly enabling original equipment manufacturers (OEMs) to create digital ‘living’ replicas of their products, commonly referred to as Digital Twins (DTs). This concept is especially relevant for Commercial Aerospace Industry (CAI) OEMs, whose business models rely heavily on high-quality service delivery, and learning about the status of each individual product could translate to cost savings of the order of millions of dollars. However, while extensive debate has taken place about the specifications of a complete, idealized DT, there is comparatively little discussion about the process and key decisions necessary for implementing such concept. This makes it difficult for managers and executives to devise strategies for implementing their DTs, as well as understanding where improvement is needed or where a competitive advantage exists. This work seeks to alleviate that gap through the development of a 10-dimension maturity model for DT implementations in CAI OEMs. Using a design science research methodology, the dimensions and their corresponding maturity levels are derived systematically. A novel framework for the derivation of maturity dimensions is presented as well. The maturity model will be helpful to industry practitioners in CAI OEMs who are seeking to benchmark their own DTs or develop an implementation strategy. For academics, this maturity model advances discussions about contextual DT implementation processes. Finally, a contribution is made to the maturity model development literature through the proposed maturity dimension derivation framework.

A method for plastic material classification using a negative-order-resonance (NOR) sensor operating at the 2.5 GHz band and support-vector-machine (SVM) for pattern recognition is presented. The proposal experimentally demonstrates the correct classification of different plastic materials based on their dielectric properties, dealing with large sources of uncertainty introduced by pellet measurements such as air gaps and position/dimension of the pellets. The proposed technique results attractive for the plastic industry as it involves a fast and nondestructive process along with the use of small circuit elements.

The modeling and representation in state space of conventional single-phase distributed generation system (in particular PV systems) allow, in the time domain, their analysis under operating conditions in steady state and transient state. The research reported in this article is oriented in particular to the determination of the periodic steady state under conditions of harmonic distortion of single-phase distributed generation systems. The analysis is carried out in the time domain, considering the particular modeling of the components of the PV system, their associated controls and their representation in the frame of reference of the state space. Results are validated against the simulator PSCAD/EMTDC®, widely accepted by the power industry.

A series of experiments are reported which serve as milestones in the development of the MPFD technology. Each test involved reactor pulsing, a controlled power excursion that results from rapid removal of control rods. During a reactor pulse, the power level increases by several orders of magnitude in a fraction of a second resulting from prompt-critical neutron generation in the core. Preliminary reactor pulse testing was conducted at the Kansas State University TRIGA Mk. II nuclear reactor (KSU). The MPFD was used to track reactor pulses of $2.77 and $2.50 worth of reactivity insertion with measured Full Widths at Half Maximum (FWHM) of 13.2 and 16.1 ms compared to theoretical FWHM of 12.2 and 14.4 ms using the Fuchs-Nordheim Model. At the University of Wisconsin Madison Nuclear Reactor (UWNR), a set of 7 detectors, each with 4 independent chambers was deployed as part of the NEUP–NEAMS collaboration between UWNR and KSU. Nine of the time-synchronized chambers were able to track six reactor pulses to provide a spatial map of neutron flux. Finally, a two-chamber MPFD was deployed inside the Idaho National Laboratory Transient Reactor Test Facility (TREAT) reactor core and successfully monitored the power excursion of a 15 GW reactor pulse with an estimated neutron flux of ~1018 n/cm2/s. These preliminary tests highlight the multi-faceted capability of the MPFD as an instrument in different research and power reactors.

This paper details a fast and efficient methodology for the simulation of the steady state response of power networks under non-sinusoidal conditions in the time domain. The methodology uses the Fourth-Order Runge-Kutta (RK4) to integrate the systems of ordinary differential equations, generated by the power system. The Numerical Differentiation method (ND) is used to accelerate the process of convergence of the state variables to the limit cycle, and Cubic Spline Interpolation (CSI) to increase the efficiency of the conventional RK4 method to obtain the time domain waveform using the fewest number of possible time steps. This curve fitting algorithm is used only once the steady state is obtained.

This work presents three hardware designs for N-point 1D-DCT used in high efficient video coding standard, which were designed taking into account all of the standard requirements, such as multiple transform sizes, finite precision approximations of DCT core matrices, scale factors, offset values, and output bit depth. The hardware architectures are flexible and parameterizable from the viewpoint of the number of inputs (N) and the number of bits of each input (n). They were implemented using one partial butterfly unit, one N/2-point 1D-DCT, N/2 multiple- constant-multiplication units, and N/2 adder units. Also, the proposed architectures were designed using minimal bit representation for the signals, shift-add blocks instead multiplications and new structures of MCM blocks in order to minimize the hardware resources and increase the performance. Synthesis results show that the proposed designs use less area and have higher operation frequency and throughput than other designs presented in the literature. Furthermore, they can support ultra-high-definition video resolutions.

Path planning is a key and complex element for every unmanned ground vehicle development. Once the 3D reconstruction of the environment is completed and the objective configuration (desired position and pose) is defined, there has to be a careful path planning algorithm. That path is subject to many restrictions: it has to be time optimal, we have limited degrees of freedom to work with since the vehicle is a non-holonomic robot, we have limited computational power and real-time constraints regarding on-board equipments, and finally the vehicle's mechanical limitations, like the maximum curvature. In this paper we present a new methodology for the path planning calculation. It was meant to be a one for all methodology, useful for different scenarios (automotive, industrial applications, mining, etc.) and different platforms (car-like vehicles, forklift trucks, etc.). This paper splits the problem in two stages. The first one faces the problem of reaching the goal with an a priori knowledge of the position affected by noise. The second approach develops a system capable of reaching the goal, enhancing the precision using a detection system, mainly based on computer vision. Particular focus is given to the interaction between the two methods proposed.

The Villar foundation was established to provide job opportunities for housewives. Weaving section has garnered the highest number of employee turnout and biggest source of income for the company. The researchers focused on how to improve their working condition by providing them a set of ergonomically designed chair and tables to decrease musculoskeletal pain and stress they feel during working and after work; eliminating these emotional, physical and psychological hindrances will increase work effectiveness when it comes to quantity and quality of their work. The researchers provided Nordic questioners to discern the condition of the employees. The researchers also conducted time study to further improve the mechanisms and problems during weaving; the following results showed that there should be an auxiliary enhancement needed to be done.

Social networking websites such as Facebook, LinkedIn, Twitter, and Weibo have been used for collaboration and knowledge sharing between users. The mining of social network data has become an important topic in data mining and computational aspects of social networks. Nowadays, it is not uncommon for most users in a social network to have many friends and in multiple social domains. Among these friends, some groups of friends are more significant than others. In this paper, we introduce a data mining technique that helps social network users find groups of friends who are significant across multiple domains in social networks.

Detection of Small Delay Defects (SDDs) is a major concern in modern circuits using nanometer technologies. They are difficult to test and an important source of test escapes, and even when SDDs do not produce functional failures, they represent a reliability risk. The detection of these defects aggravates in the presence of process variations. In this paper, a methodology to detect SDDs in the presence of process variations using delay correlation information between paths of a circuit is proposed. This methodology exploits the concept that for two highly correlated paths, an important part of the delay variance in one path can be described by the delay variance in the second path. The methodology has been further extended to consider multiple path correlation thus improving the detection of SDDs. This methodology is able to distinguish delay defects from process variations. A metric is also proposed to quantify the SDD screenable variance that represents the percentage of variance where a defect can be detected. A statistical timing analysis framework has been developed and implemented to compute timing information and Inter-Path Correlation (IPC). Spatial and structural correlation, and random dopant fluctuations are considered. Simulation results in 74LS85 and ISCAS85 benchmark circuits evince the feasibility of the proposed methodology.

The present study shows the feasibility of using Field Programmable Gate Arrays (FPGA) for the generation of independent signals intended to drive therapeutic devices based on focused ultrasound. These devices require hundreds of independent signals where it is required to control amplitude, phase and frequency of sinusoidal signals. Since Magnetic Resonance Imaging (MRI) is used often for the guidance of the therapy, the driving electronics has to be compatible with the MRI environment. The design of the system and results from first tests are shown. Results indicated that up-to 80 independent signals can be generated using a Cyclone II unit (Altera, San Jose, California, US) and this number can be increased with a different family of FPGA or using a matrix of FPGAs.

Software-based self-test strategies have been mainly proposed to tackle microprocessor testing issues, but may also be applied to peripheral testing. However, testing highly embedded peripherals (e.g., DMA or Interrupt controllers) is a challenging task, since their observability and controllability are even more reduced compared to microprocessors and to peripherals devoted to I/O communication (e.g., serial or parallel ports). In this paper we describe an approach to develop functional tests for system peripherals embedded in SoCs that can be used for both design validation and testing. The presented methodology requires two correlated phases: module configuration and module operation. The first one prepares the peripheral on the different operation modes, whereas, the second one is in charge of exciting the whole device and observing its behavior. A methodology for generating suitable test programs is proposed, and preliminary experimental results demonstrating the method effectiveness for an embedded DMA controller are finally reported.

This article presents the design of a baseband processor for software radio, which uses carrier synchronizer and bit detector-synchronizer circuits based on algorithms implemented in hardware, and an inverse tangent circuit based on the CORDIC algorithm. In this case, the functional blocks of the processor can be reconfigured to support multiple modulation formats and signal processing tasks in the digital domain.

Enrique Pacheco, Roberto Conte, Francisco J. Mendieta, Ramon Muraoka, Jose Luis Medina, Arturo Arvizu CICESE Research Center US mail address: PO BOX 434944 San Diego, CA 92143-4944 Km. 107 Carretera Tijuana-Ensenada, Ensenada, B.C. Mexico 22860 Tel. +52 646 175 0554 Fax.+52 646 175 0555 epacheco@cicese.mx, conte@cicese.mx, jmendiet@cicese.mx, rmuraoka@cicese.mx, jmedina@cicese.mx, arvizu@cicese.mx

A telemetry and command subsystem developed in Mexico is presented. The goal of this project is the design, construction, implementation and testing of a RF subsystem to be used on a digital communication link at 148 MHz (VHF band, uplink) and 400 MHz (UHF band, downlink), for the SATEX I microsatellite. The whole system consists of transmitter-receiver equipment for the satellite and its counterpart equipment for the master Earth station. The system also includes a minimal computation subsystem, which acts as a backup in case both the main and redundant onboard computers fail, generating a survival communications mode. Both terrestrial and space segments have an active (hot standby) 2:1 redundancy. A description of the developed prototype and its details are presented.