Hasil untuk "Electrical engineering. Electronics. Nuclear engineering"

Serena Basile, Johannes F.L. Goosen

As engineering applications become increasingly complex, the need for miniaturization is present in several technological fields. Places hardly reachable by traditional tools and machines, can be accessed thanks to miniaturized devices and, especially when such devices are remotely controlled or autonomous, it implies the need for miniaturized, standalone actuators. Most high-energy density actuators for these applications can not be operated if untethered from an external power-supply.In this study, we investigate the manufacturing of a mesoscale compliant expansion chamber for a miniaturized chemical-based actuator. Photopolymerization and material jetting are used for manufacturing the prototypes, exhibiting dimensions of 9.8 mm diameter, 7.5 mm height and 140 μm thickness. These dimensions are such as to allow the device to fit inside of the flapping wings micro aerial vehicle (FWMAV) that it has to power. Fabrication of such dimensions, along with the peculiar geometry of the chamber, taps into the limitations of the photopolymerization process and highlights areas of improvement for this rapidly-developing technology. The devices are successfully tested for a linear motion, mimicking that of a cylinder-piston combination, as in a conventional expansion chamber, and are actuated by a pressure pulse.

J. de Curtò, Cristina LiCalzi, Julien Tubiana Warin et al.

This paper presents innovative solutions to critical challenges in planetary and deep-space exploration electronics. We synthesize findings across diverse mission profiles, highlighting advances in: (1) MARTIAN positioning systems with dual-frequency transmission to achieve $\pm$1m horizontal accuracy; (2) artificial reef platforms for Titan's hydrocarbon seas utilizing specialized sensor arrays and multi-stage communication chains; (3) precision orbital rendezvous techniques demonstrating novel thermal protection solutions; (4) miniaturized CubeSat architectures for asteroid exploration with optimized power-to-mass ratios; and (5) next-generation power management systems for MARS rovers addressing dust accumulation challenges. These innovations represent promising directions for future space exploration technologies, particularly in environments where traditional Earth-based electronic solutions prove inadequate. The interdisciplinary nature of these developments highlights the critical intersection of aerospace engineering, electrical engineering, and planetary science in advancing human exploration capabilities beyond Earth orbit.

Amirreza Hosseini, Amro M. Farid

Within the project management context, project scheduling serves as an indispensable component, functioning as a fundamental tool for planning, monitoring, controlling, and managing projects more broadly. Although the resource-constrained project scheduling problem (RCPSP) lies at the core of project management activities, it remains largely disconnected from the broader literature on model-based systems engineering (MBSE), thereby limiting its integration into the design and management of complex systems. The original contribution of this paper is twofold. First, the paper seeks to reconcile the RCPSP with the broader literature and vocabulary of model-based systems engineering and hetero-functional graph theory (HFGT). A concrete translation pipeline from an activity-on-node network to a SysML activity diagram, and then to an operand net is constructed. Using this representation, it specializes the hetero-functional network minimum-cost flow (HFNMCF) formulation to the RCPSP context as a systematic means of HFGT for quantitative analysis and proves that the RCPSP is recoverable as a special case of a broader model. Secondly, on an illustrative instance with renewable and non-renewable operands, the specialized HFNMCF, while producing similar schedules, yields explicit explanations of the project states that enable richer monitoring and control. Overall, the framework preserves the strengths of the classical RCPSP while accommodating real-world constraints and enterprise-level decision processes encountered in large, complex megaprojects.

ZHAO Yongjian, ZHAO Zhanchun, ZHANG Ding et al.

Driven by both business and technology, the communication industry is focused on smart network operations. It is an industry consensus to promote network intelligent operation with autonomous networks as the driving force. It was analyzed that operational support system (OSS) was the core component of the three-layer architecture of autonomous network, and the key to improve the level of autonomous networks was to enhance the intelligence capability of OSS. Specific implementation schemes such as the definition method of OSS product business scope, the analysis of the shortcoming of OSS product ability,and systematic improvement of OSS product capabilities driven by autonomous networks were elaborated. The solution was described in detail using the digital operation value scenario of broadband services as an example. Finally, the intelligent ability map of OSS driven by autonomous network was discussed. Improving the intelligence capability of OSS for autonomous network can effectively promote the research and development direction of OSS, and guide the planning and research and development of OSS products for operators.

Antoine Verreault, Paul-Vahe Cicek, Alexandre Robichaud

Oversampling analog-to-digital converters (ADC) serve as the backbone of high-performance, high-precision data interfaces, owing to their remarkable ability to filter out quantization noise. This attribute makes them the preferred choice for applications requiring high signal-to-noise ratio (SNR) and moderate bandwidth, with great design flexibility. This paper provides an extensive survey of the latest advancements in oversampling ADC tailored for such applications as documented in recent literature. Specifically focusing on design techniques employed within the last five years, the survey encompasses various oversampling ADC architectures, including discrete-time and continuous-time <inline-formula> <tex-math notation="LaTeX">$\Delta \Sigma $ </tex-math></inline-formula>, noise-shaping SAR, zoom, incremental, and time-domain modulators. A thorough performance comparison between these different topologies is presented, highlighting designs that achieve the best figures-of-merit. Furthermore, the paper explores circuit-level design trends commonly shared among these architectures, with particular attention given to amplifier designs for loop filters. Conclusions drawn highlight the limitations of much of the research works in the context of implementing ADC within complete systems, while also providing insight into the expected future trends that will shape the field moving forward.

Xianzhe Shi, Xiuxia Wang, Biao Chen et al.

Oxygen has been known as an effective strengthening element in titanium (Ti) and its alloys. However, an over-dose of oxygen can also lead to embrittlement of Ti alloys. To precisely control and push the limit of oxygen in Ti and its alloys, we studied the decomposition process of Ti oxides in pure α-Ti matrix using an in-situ high-temperature scanning electron microscope. The experimental results revealed that TiO particles decomposed in α-Ti at elevated temperatures and the oxygen atoms gradually diffused into the matrix, following the Fick’s second law. Then, the samples with different oxygen contents were produced using the aforementioned strategy, for which the oxygen content, microstructure, and mechanical properties were measured. The results revealed that the oxygen content can be precisely controlled, which can achieve an ultra-high tensile strength of close to 1100 MPa, at no expense of elongation-to-failure, with incorporating 0.87 wt% oxygen. An analysis showed that the strength contribution from oxygen follows the Labusch law. These findings offer a novel approach to design high-performance Ti alloys with non-toxic and cheap elements.

Hyun-Jun Choi, Kyung-Wook Heo, Jee-Hoon Jung

Isolated bi-direction DC-DC converters are widely used for energy storage systems (ESS) of DC microgrids. Particularly, a current-fed isolated bi-directional DC-DC converter (CF-IBDC) receives much attention due to its merits such as the naturally attenuated current ripple on the battery side. However, high efficiency cannot be obtained at the light and heavy load conditions under the conventional control methods. In this paper, a hybrid switching modulation is proposed to improve the power conversion efficiency of the CF-IBDC under light and heavy load conditions. The duty cycle of the secondary sides and the phase shift angle are independently controlled according to the amount of the transferred power. The control strategy is based on the optimization of zero-voltage switching (ZVS) conditions and the minimization of the circulating current in the power converter. Using the proposed control algorithm, the ZVS capability can be obtained under the entire load condition, and the circulating current can be minimized under the single phase-shift modulation (SPSM). Experimental results with a 1-kW laboratory prototype CF-IBDC validate the effectiveness of the proposed modulation algorithm.

Mao Zhu, Xi Luo, Zhiyi Li et al.

Collecting fine-grained data on electricity usage can reduce the user’s energy cost by accurate demand response and improve the services from utilities. However, non-intrusive power load monitoring (NILM) technology shows that these data will reveal the user’s privacy. In this paper, we first design a price-sensitive BLH scheme which achieves differential privacy. Then regarding such issues above, we propose a price-sensitive cost-friendly differential privacy (PCDP) scheme through a contextual multi-armed bandit framework. Last, realistic electricity consumption data is extracted to validate the proposed method. The results show that our method provides effective privacy protection and achieve considerable cost saving.

Julian Frattini, Davide Fucci, Daniel Mendez et al.

Context: Advances in technical debt research demonstrate the benefits of applying the financial debt metaphor to support decision-making in software development activities. Although decision-making during requirements engineering has significant consequences, the debt metaphor in requirements engineering is inadequately explored. Objective: We aim to conceptualize how the debt metaphor applies to requirements engineering by organizing concepts related to practitioners' understanding and managing of requirements engineering debt (RED). Method: We conducted two in-depth expert interviews to identify key requirements engineering debt concepts and construct a survey instrument. We surveyed 69 practitioners worldwide regarding their perception of the concepts and developed an initial analytical theory. Results: We propose a RED theory that aligns key concepts from technical debt research but emphasizes the specific nature of requirements engineering. In particular, the theory consists of 23 falsifiable propositions derived from the literature, the interviews, and survey results. Conclusions: The concepts of requirements engineering debt are perceived to be similar to their technical debt counterpart. Nevertheless, measuring and tracking requirements engineering debt are immature in practice. Our proposed theory serves as the first guide toward further research in this area.

Nicolas Schunck, David Regnier

Atomic nuclei are quantum many-body systems of protons and neutrons held together by strong nuclear forces. Under the proper conditions, nuclei can break into two (sometimes three) fragments which will subsequently decay by emitting particles. This phenomenon is called nuclear fission. Since different fission events may produce different fragmentations, the end-products of all fissions that occurred in a small chemical sample of matter comprise hundreds of different isotopes, including $α$ particles, together with a large number of emitted neutrons, photons, electrons and antineutrinos. The extraordinary complexity of this process, which happens at length scales of the order of a femtometer, mostly takes less than a femtosecond but is not completely over until all the lingering $β$ decays have completed - which can take years - is a fascinating window into the physics of atomic nuclei. While fission may be more naturally known in the context of its technological applications, it also plays a pivotal role in the synthesis of heavy elements in astrophysical environments. In both cases, experimental measurements are not sufficient to provide complete data. Simulations are needed, yet at levels of accuracy and precision that pose formidable challenges to nuclear theory. The goal of this article is to provide a comprehensive overview of the theoretical methods employed in the description of nuclear fission.

Junghyun Bae, Stylianos Chatzidakis

Nuclear materials accountability and nonproliferation are among the critical tasks to be addressed for the advancement of nuclear energy in the United States. Monitoring spent nuclear fuel is important to continue reliable stewardship of SNF storage. Cosmic ray muons have been acknowledged a promising radiographic tool for monitoring SNF due to their highly penetrative nature and high energy. Cosmic ray muons are more suitable and have been used for imaging large and dense objects. Despite their potential in various applications, the wide application of cosmic ray muons is limited by the naturally low intensity at sea level. To efficiently utilize cosmic ray muons in engineering applications, trajectory and momentum must be measured. Although various studies demonstrate that there is significant potential for measuring momentum in muon applications, it is still difficult to measure both muon scattering angle and momentum in the field. To fill this critical gap, a muon spectrometer using multilayer pressurized gas Cherenkov radiators was proposed. However, existing muon tomographic algorithms were developed assuming monoenergetic muon scattering and are not optimized for a measured polyenergetic momentum spectrum. In this work, we develop and evaluate a momentum integrated muon scattering tomography algorithm. We evaluate the algorithm on its capability to identify a missing fuel assembly from a SNF dry cask. Our results demonstrate that image resolution using MMST is significantly improved when measuring muon momentum and it can reduce monitoring time by a factor of 10 when compared to that of a conventional muon imaging technique in terms of systematically finding a missing FA.

Jovan Carlo S. Caballero, Carl Benedick D. Ching, S. Co et al.

With or without a crisis such as a pandemic, the continuous service of quality healthcare is a necessity for a community to thrive. Given the current problem, the researchers determined that the integration of Availability Management and Events and Monitoring Management Information Technology Infrastructure Library (ITIL) frameworks in a healthcare mobile application to ensure the reliability and effectiveness of the services provided. Hence, the researchers created the LifeDoc: Availability and Monitoring System of Online Medical Consultation that caters to both patients and doctors and is available for Android users only. Technologies such as React Native and WebRTC were used for the development of the mobile application wherein the processing of information occurring throughout the system is stored in a secure cloud-hosted database called MongoDB. The researchers adopted the Agile Methodology approach throughout the execution of the project as this approach was determined by the researchers to be the effective and suitable approach given the time constraints and user requirements. Tests were performed in the system based on the Institute of Electronics and Electrical Engineering (IEEE) standard for Software Test Documentation to certify that the functionalities of the project were working according to specification. The importance of implementing appropriate service management framework coupled with mobile technology makes quality healthcare accessible and a right for all.

Mengxue JIAO, Ji QIU, Tao JIN et al.

In this paper, three different shapes of indenters were used to perform quasi-static out-of-plane uniaxial compression and indentation tests on three commercial hexagonal aluminum honeycombs with different densities. In order to distinguish the different tearing conditions of the single-layer and double-layer aluminum honeycomb walls during indentation, a new indentation experiment was designed. By controlling the shape of pattern and the location of indentation, different tearing conditions in indentation experiment were measured separately. The deformation mode of the aluminum honeycomb when pressed was analyzed. It is found that as the size of the pattern increases, the peak stress of the indentation experiment decreases significantly. As the size of the indenter increases, the platform stress of aluminum honeycomb shows a downward trend and tends to approach the compression platform stress, while the tear strength remains basically stable within a certain scale. As the size of the indenter continues to increase, the proportion of tearing force to the total indenting force gradually decreases, and the tearing strength loses its stability. At this time, the tear strength can no longer be used as a stable mechanical parameter to measure the tearing condition during indentation.

Tianshu WANG, Ying ZHANG, Ce YU et al.

The nonlinear spectral broadening light source was used as a partially coherent carrier source with high repetition frequency to carry out experimental research on high-speed information transmission in atmospheric turbulence channels.A partially coherent beams source with nonlinear spectral broadening was obtained by pumping a highly nonlinear fiber with a picosecond fiber laser, and the repetition frequency could reach 10 GHz.The 10 Gbit/s pulse high-speed digital modulation was used and transmitted through a simulated atmospheric turbulence channel, the signal-to-noise ratio of the coherent optical carrier and partially coherent optical carrier before and after the turbulent channel transmission is reduced from 16.83 dB and 11.83 dB to 4.31 dB and 5.64 dB, respectively.In the simulated atmospheric turbulence channel at ∆T=230℃, when the bit error rate is 3.8×10^-3, the sensitivity of partially coherent optical carrier links reaches-27.8 dBm, which is 1.6 dB higher than that of coherent optical carriers.

Pande Ketut Sudiarta

To find out the need for fiber optic access network devices from NOC to rooms at Udayana University, Sudirman Campus, fiber to the home network design was made with Gigabit Passive Optical Network (GPON) technology. Selection of GPON technology to reduce the number of ports on OLT and the number of fiber cores compared to the existing technology using point to point. Assuming the bitrate in each room is 21 Mbps and 291 rooms to be served, it takes 5 OLT ports on the NOC. Feeder Cable Network consists of 5 cores distributed to each location using 3 units of 1: 4 splitter, 4 units of 1: 8 splitter, 6 units of 1:16 splitter, 1:32 splitter of 6 units. To maintain service quality, 16 amplifiers are needed. The required fiber cable length is 2.5 km. The quality of service is tested using the Optisystem simulator. The result is that at the closest distance the PRx value is -14.059 dBm, with BER 6.13608 e-103, Q Factor 21.511. Meanwhile, at the farthest distance, the PRx value is -14.105 dBm, with BER of 1.52751 e-120, and Q Factor 23.3159. The results obtained still meet the ITU-T G.984.2 standard

Sabah Al-Fedaghi

The term behavior engineering (BE) encompasses a broad integration of behavioral and compositional requirements needed to model large-scale systems. BE forms a connection between systems-engineering processes and software-engineering processes. In software engineering, interpreting requirements can be perceived as specifying behavior, which is viewed in terms of chronology of events in the modeled system. In this paper, we adopt BE in its general and integrating sense to search for a unifying notion of an event as a fundamental behavior-modeling concept. We examine several bodies of research with various definitions of an event and its basic units and structure. We use the thinging machine (TM) model to analyze notions related to events, including Dromey s behavior trees, fluents (change over time), recurrent events, and Davidson s events. The results point to an underlying meaning that can lead to a unifying event concept.

Eamon Whalen, Azariah Beyene, Caitlin Mueller

This paper introduces the Simulated Jet Engine Bracket Dataset (SimJEB): a new, public collection of crowdsourced mechanical brackets and accompanying structural simulations. SimJEB is applicable to a wide range of geometry processing tasks; the complexity of the shapes in SimJEB offer a challenge to automated geometry cleaning and meshing, while categorical labels and structural simulations facilitate classification and regression (i.e. engineering surrogate modeling). In contrast to existing shape collections, SimJEB's models are all designed for the same engineering function and thus have consistent structural loads and support conditions. On the other hand, SimJEB models are more complex, diverse, and realistic than the synthetically generated datasets commonly used in parametric surrogate model evaluation. The designs in SimJEB were derived from submissions to the GrabCAD Jet Engine Bracket Challenge: an open engineering design competition with over 700 hand-designed CAD entries from 320 designers representing 56 countries. Each model has been cleaned, categorized, meshed, and simulated with finite element analysis according to the original competition specifications. The result is a collection of 381 diverse, high-quality and application-focused designs for advancing geometric deep learning, engineering surrogate modeling, automated cleaning and related geometry processing tasks.

Letizia Jaccheri, Sandro Morasca

Background: A growing amount of software is available to children today. Children use both software that has been explicitly developed for them and software for general users. While they obtain clear benefits from software, such as access to creativity tools and learning resources, children are also exposed to several risks and disadvantages, such as privacy violation, inactivity, or safety risks that can even lead to death. The research and development community is addressing and investigating positive and negative impacts of software for children one by one, but no comprehensive model exists that relates software engineering and children as stakeholders in their own right. Aims: The final objective of this line of research is to propose effective ways in which children can be involved in Software Engineering activities as stakeholders. Specifically, in this paper, we investigate the quality aspects that are of interest for children, as quality is a crucial aspect in the development of any kind of software, especially for stakeholders like children. Method: Our contribution is based mainly on an analysis of studies at the intersection between Software Engineering (especially software quality) and Child Computer Interaction. Results: We identify a set of qualities and a preliminary set of guidelines that can be used by researchers and practitioners in understanding the complex interrelations between Software Engineering and children. Based on the qualities and the guidelines, researchers can design empirical investigations to obtain deeper insights into the phenomenon and propose new Software Engineering knowledge specific for this type of stakeholders. Conclusions: This conceptualization is a first step towards a framework to support children as stakeholders in software engineering.

Sharifah Fauziah, Syed Draman, Wan Dorishah et al.

International Conference of Emerging Challenges in Engineering and Current Technology (ICECT III) 30-31 March 2021 ICECT III 2021 is organised by Universiti Teknologi MARA, Terengganu Branch to provide an opportunity to research scholars, delegates, academicians, and students to engage in dialogues on a wide range of topics in engineering challenges and current technology. Formerly launched in 2016 as the International Symposium of Engineering Technologies (ISET), the conference name was then changed to the International Conference on Engineering and Computing Technology (ICECT II) in 2018. Now the conference is rebranded as the International Conference of Emerging Challenges in Engineering and Current Technology (ICECT III) to ensure it is relevant to the latest emerging challenges in engineering and current technology. The main aims of ICECT III 2021 are to promote the emerging development of the current technology in the engineering field to encourage engineering applications on the current state-of-the-art in the various engineering fields. The conference provides a mechanism to communicate findings, solutions or innovations among scholars and scientists as well as motivate scholars, scientists, and engineers in related fields to provide to its body of knowledge. The conference focused on original research work in a multiple range of areas, including Chemistry and Chemical Engineering, Electrical and Electronics Engineering, Materials and Mechanical Engineering, Advanced Computing Technology, Applied Sciences and Mathematics. Also, it serves as a conduit for channelling advanced engineering research and applications to the regional industry. All submissions are subjected to rigorous review before an acceptance decision is made. The papers published in these proceedings will contribute to a better understanding of the related problem, the current solution and the future innovation as well as will serve as a reference for researchers and engineers in the field of electrical, mechanical, chemical, advanced computing technology and applied mathematics. The online live streaming presentation is used as a method of presentation within the two-day conference. List of Organizing Committee of Conference, Editors of ICECT III 2021 are available in this pdf.

李康丽, 李永志, 孙国栋

Effect of quenched and tempered treatment, normalizing & quenched and tempered treatment on micro¬structure and properties of 42CrMo forging crankshaft steel is studied by means of metallographic microscope observation and mechanical performance analysis. The results show that after the quenching and tempering treatment ( 860 ℃ quenched + 580℃ tempered) , the base structure for the forging crankshaft billet is temped sorbite and much amount of white ferrite with coarse grain non-homogeneously distributed at the central area of crankshaft. Its mechanical properties are TS 997 ~ 1211 MPa, YS 990 〜1204 MPa, el. 11% ~ 13% , RA 40% -48% , and impact energy 72 ~92 J. On the contrary,with a normalizing pretreatment(880℃ air cooling) before the quenching and tempering treatment process, the microstructure for the 42CrMo forging crankshaft steel become more uniform, its mechanical properties are TS 1100 〜1220 MPa, YS 1107 ~ 1188 MPa, el. 13% ~ 15% , RA 50% ~56% and impact energy 83 ~91 J. Therefore, the normalizing pretreatment at 880 °C air quenching at 860 °C and high temperature tempering treatment at 580 T is the optimized heat treatment process for the 42CrMo forging crankshaft steel.