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Offsets Reconstruction Method for Clock Skew Measurement Over High-Jitter Communication

SN Computer Science 2025年第5期6卷 1-14页

作者： Sastra, Nyoman Putra Saputra, Komang Oka Teng, Wei-Chung Study Program of Electrical Engineering Faculty of Engineering Udayana University Jalan Raya Kampus Bukit Jimbaran Bali Badung 80361 Indonesia Department of Computer Science and Information Engineering National Taiwan University of Science and Technology No. 43 Section 4 Keelung Rd Taipei 106 China

Measuring clock skew of devices over a network fully relies on the offsets, the differences between sending and receiving times. Offsets that shape a thick line are the most ideal one as their slope is directly the clock skew sought. When some outliers separate from the thick line due to higher delay jitter, current advanced approaches use the lower bound or the majority of offsets to derive accurate clock skew. However, outliers in offsets that shape parallel dotted lines, reduce the availability of offsets in the lower region, and scatter widely the offsets from their majority zone. These conditions drive the current skew estimation approaches to lose their accuracy. This paper then developed a new method, which reconstructs back the outliers into their origin positions, in order to provide ideal offsets for clock skew measurement. The experimental evaluations have demonstrated that the clock skew accuracy of dotted-lines offsets tampered by outliers was improved from 2.1 to 0.9 ppm by the proposed reconstruction method. For a broader purpose, the reconstruction method has been adjusted to be implemented also on non-dotted-lines offsets. The robustness of the proposed method for this case has also been exhibited by the very ideal reconstructed offsets that shape like a thick line. © The Author(s) 2025.

关键词： Clock skew Delay jitter Dotted lines Hough transform

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Identification of spalling in concrete structures by a hammering test using autoencoder 8th

Identification of spalling in concrete structures by a hamme...

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8th International Symposium on Life-Cycle civil engineering, IALCCE 2023

作者： Emoto, Hisao Fukui, Nobuki Iitaka, Yuto Kanazawa, Shin-Ichi Social Systems and Civil Engineering Tottori University Tottori-City Japan Industrial Technology and Systems Engineering Fukushima College Iwaki-City Japan Civil Engineering Program Faculty of Engineering Niigata University Niigata-City Japan

ISBN: (纸本)9781003323020

Visual inspection of bridges is important to maintain the sustainability of civil infrastructure. A hammering test is one of the non-destructive and verified methods used for this purpose, by which an expert inspector identifies spalling inside a concrete structure. The reliability of this method depends on the technique of the inspector. However, Japan society faces the problem of a scarcity of labor across all fields. Because of this, there are few training opportunities for new inspectors to learn the technique. This study aims to identify spalling concrete by using an autoencoder, instead of professional inspectors. First, a spalled concrete specimen was used to record the hammering sounds. The experimental method and a comparison of frequency spectra at each level of damage were described. Next, the autoencoder was applied to identify spalling concrete, and a comparison of the identification precision at each damage level was conducted. The results of the analysis show that spalling concrete can be identified by autoencoder to a concrete thickness of less than 30 mm. © 2023 The Author(s).

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Key fuel characteristics and techno-economic aspects of torrefied rubberwood biomass pellets produced by incorporating various cassava-based binders at varied doses

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Environmental Science and Pollution Research 2024年第25期31卷 37663-37680页

作者： Kongto, Pumin Palamanit, Arkom Chaiprapat, Sumate Tippayawong, Nakorn Khempila, Jarunee Ruangim, Panatda Energy Technology Program Department of Interdisciplinary Engineering Faculty of Engineering Prince of Songkla University 15 Kanjanavanich Rd. Songkhla Hat Yai90110 Thailand Research Center Faculty of Engineering Prince of Songkla University 15 Kanjanavanich Rd. Songkhla Hat Yai90110 Thailand Department of Civil and Environmental Engineering Faculty of Engineering Prince of Songkla University 15 Kanjanavanich Rd. Songkhla Hat Yai90110 Thailand Department of Mechanical Engineering Chiang Mai University 239 Huay Kaew Rd. Chiang Mai Muang District 50200 Thailand Physics Program Faculty of Science and Technology Rajabhat Maha Sarakham University 80 Nakhon Sawan Rd. Maha Sarakham Mueang District 44000 Thailand

Improving energy content and hydrophobic nature of woody biomass can be pursued through torrefaction. This gives torrefied biomass with a low bulk density, potentially increasing storage and transport costs. To overcome this issue, densifying the torrefied biomass is necessary. However, poor binding of particles makes densification challenging without using a binder. Therefore, the aim of this study was to investigate the physicochemical characteristics and techno-economic aspects of torrefied rubberwood biomass (TRWB) when pelletized using various cassava-based binders at different blending ratios. The selected binders included cassava starch (CS), cassava pulp (CP), and cassava chip (CC). Each binder at 5%, 10%, or 15% (wt.) was mixed with TRWB and water before pelletizing using a flat die machine. The results revealed that pelletizing TRWB with different cassava-based binders at various blending ratios influenced the physicochemical characteristics of the TRWB pellets, particularly dimensions, bulk density, fuel and atomic ratios, and energy content. The TRWB pellets demonstrated energy densities in the range of 7.95–11.39 GJ/m3, and their mechanical durability and fine content fell within acceptable ranges. The TRWB pellets maintained their shape during 120 min of water soaking, with water absorption levels varying by binder dose. The pelletizing ability, material, and energy costs of TRWB pellets depend on binder type and dose. CP can be applied as a binder for pelletizing torrefied rubberwood biomass. However, the mechanical durability of the product needs to be above the user requirement or standard. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.

关键词： Pelletizing

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Influence of rice husk ash and hybrid fiber on engineering properties of densified high-performance fiber-reinforced concrete

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Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 2023年第11期237卷 2845-2857页

作者： Vo, Duy-Hai Nguyen, Minh-Hieu Nguyen, May Huu Hwang, Chao-Lung Huynh, Trong-Phuoc The University of Danang University of Technology and Education Danang Viet Nam Vinh Long Department of Construction Vinh Long Viet Nam Civil and Environmental Engineering Program Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima Japan Department of Bridge and Tunnel Faculty of Civil Engineering University of Transport Technology Hanoi Viet Nam Taiwan Building Technology Center National Taiwan University of Science and Technology Taipei Taiwan Faculty of Civil Engineering College of Engineering Can Tho University Can Tho Viet Nam

Conventional concrete significantly affects the environment due to high CO2 emission into the atmosphere during the production process. In order to improve concrete performance and arrest the incidence of global warming, the use of additive materials for cement replacement has been promoted worldwide. This study was designed to investigate the mechanical properties of high-performance fiber-reinforced concrete (HFRC) produced using rice husk ash (RHA) and hybrid fiber (HF) in accordance with the densified mixture design algorithm (DMDA) mix design method. Samples were produced using RHA as a direct replacement for cement at 10%, 20%, and 30%. HF, comprising steel and polypropylene fibers, was added (by volume) to the 20% RHA group mixture to improve the HFRC sample properties. Based on the experimental results, higher RHA contents had a generally negative effect on the fresh properties of the HFRC mixtures. Compressive strength values ranged from 53 to 72 MPa with various RHA and HF content. RHA replacement levels up to 20% had an insignificant effect on the strength development and dynamic modulus of the HFRC samples. However, the addition of HF improved splitting tensile strength, flexural strength, and dynamic modulus remarkably at all curing ages. Furthermore, the 91-day drying shrinkage was in the ranges of 0.032%–0.039% and 0.023%–0.034% using different RHA and HF levels, respectively. Increasing both RHA and HF contents significantly reduced drying shrinkage in the samples. Multivariable regression was also performed, clarifying that all tested results were consistent and had good correlations. The results of this study also provide a potentially effective use for abundantly available industrial waste products such as fly ash (FA) and RHA to promote the production of greener and more sustainable concrete. © IMechE 2023.

关键词： Bending strength

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Microplastic Contamination in Urban Groundwater: A Case study From Jakarta Megacity, Indonesia

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Scientific World Journal 2024年第1期2024卷

作者： Wilyalodia, Hefty Clarissa Moersidik, Setyo Sarwanto Pratama, Mochamad Adhiraga Program Study of Environmental Engineering Department of Civil Engineering Faculty of Engineering Universitas Indonesia Depok Indonesia

Microplastics, classified as emerging contaminants, are recognized for their pollution of various environments, including groundwater. This study focuses on Jakarta, a major city in Asia where some communities still rely on groundwater as their source of clean water. We analyzed 121 groundwater samples from West Jakarta and South Jakarta to assess microplastic abundance and characteristics including color, shape, size, and material. The study also explored the correlation between microplastic abundance and influencing factors such as distance to septic tanks, distance to temporary waste disposal sites, Escherichia coli concentrations, and total coliform concentrations. The results indicate microplastic concentrations ranging from 28 to 236 particles/L with averages of 104 particles/L in West Jakarta and 78 particles/L in South Jakarta. Fragments were the most common shapes (85.68%), followed by fibers (12.86%), films (0.8%), and microbeads (0.66%). Black (85.93%) was the dominant color of microplastics, followed by red (8.2%), transparent (3.13%), blue (1.76%), yellow (0.75%), and green (0.23%). Microplastic size ranged from 20 μm to 3.76 mm, with the dominant polymer materials being Tencel, cellophane, and polyethylene (PE). Further analysis showed a significant correlation between microplastic abundance and distance to temporary waste disposal sites, with closer proximity resulting in higher concentrations. Trends in correlations between microplastic abundance and distance to septic tanks, E. coli concentration, and total coliform concentration were observable but not significant. Copyright © 2024 Hefty Clarissa Wilyalodia et al.

关键词： groundwater Jakarta microplastic septic tank water well

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Polymer-based dampening layer application to improve the operating shock tolerance of hard disk drive

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Journal of engineering and Applied Science 2022年第1期69卷 1-20页

作者： Djamari, Djati Wibowo Yap, Fook Fah Budiman, Bentang Arief Triawan, Farid Mechanical Engineering Study Program Sampoerna University Jakarta Indonesia School of Mechanical and Aerospace Engineering Nanyang Technological University Singapore Singapore Faculty of Mechanical and Aerospace Engineering Institut Teknologi Bandung Bandung Indonesia

This paper discusses a passive vibration control method to improve the shock tolerance of hard disk drives (HDDs) in operating condition (op-shock tolerance). Past works in improving the HDDs’ op-shock tolerance includes (i) parking the head when shock is detected, (ii) installing a lift-off limiter, (iii) structural modification of the suspension, and (iv) installing an external vibration isolation. Methods (i) and (iv) have practical issues, method (ii) works only on single shock direction, and method (iii) requires major engineering design/manufacturing work. Compared to these works, this paper proposes a method which has no practical issues and without requiring major engineering design/manufacturing work. The proposed method is to apply a polymer-based dampening layer on the backside of the baseplate with the purpose of increasing the damping ratio of the 1st bending mode of the baseplate. The location of the dampening layer on the baseplate is first determined by modal analysis and then fine-tuned by non-op-shock tests. The op-shock tolerance improvement is confirmed by op-shock tests where 2.5″ HDD with the dampening layer on the baseplate can withstand a 300G 0.5-ms shock without failure while unmodified HDD can only withstand 250G 0.5-ms shock without failure. © 2022, The Author(s).

关键词： Damping

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Removing or Avoiding the Camera Focus Light Appearing on Glossy or Bouncing Surfaces by Light Guiding and Image Warping 22

Removing or Avoiding the Camera Focus Light Appearing on Glo...

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4th International Conference on Information Technology and Computer Communications, ITCC 2022

作者： Rompis, Lianly Electrical Engineering Study Program Faculty of Engineering Universitas Katolik de la Salle Manado Indonesia

ISBN: (纸本)9781450396820

Digital picture or image becomes more and more important in people's daily life, such as for administration, documentation, active communications, and learning processes. People also demand the exchange of information through digital applications and social media. Taking picture or photo of a document, book, certificate, or thing is usually done by the help of digital scanner, but not all these stuffs can be converted into digital with a scanner. In specific condition people need real image transfer and will take photo of the real view directly using their own digital camera or smartphone camera. From author experience and observations, when taking photos of a document or book or certificate or thing normally with plastic cover or glass surface or bouncing surface, we clearly got an annoying light came from the camera focus light or flash that usually creates noise and messy image. This research was conducted based on the idea to remove or avoid getting the unwanted or disturbing light while taking photos of glossy or bouncing surfaces. A procedure to get a clear and smooth image instead of noise and broken image was derived and implemented by author using light guiding and image warping. These two methods bring accurate images that are necessary for communication needs and facilitate better future works without compromising security policies and people's rights. As the research methodology, author performed literature study, observation, analysis, and implementation. The result of this research offers a good procedure and method that can help people getting clear photos or pictures of a glossy or bouncing surface, advance research to be implemented related to camera technology, and best comprehension to improve photography techniques for future developments. © 2022 ACM.

关键词： Image enhancement

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Improvement of PID Based on Fuzzy Logic Controller for Controlling Attitude of a Quadcopter 1

Improvement of PID Based on Fuzzy Logic Controller for Contr...

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1st International Conference of Adisutjipto on Aerospace Electrical engineering and Informatics, ICAAEEI 2024

作者： Rizki Dalimunthe, Ernando Sibuea, Horas Nico L. P. Rama Setiadi, Dirga Jayadi, Akhmad Persada Sembiring, Jaka Pranita, Elka Universitas Teknokrat Indonesia Faculty of Engineering and Computer Science Bandar Lampung Indonesia Politenik Negeri Lampung Informatic Management Study Program Bandar Lampung Indonesia

ISBN: (纸本)9798331507930

The quadcopter has a fairly simple mechanical design because it does not require other drives to perform various movements such as roll, pitch, and yaw. The simplicity of this mechanical design has a considerable impact on the complexity of its control. Therefore, it is necessary to have a good control method to maintain the stability of the quadcopter. The research aims to maintain stability of quadcopter by using a combination of the Fuzzy Logic Controller (FLC) with the Proportional-Integral-Derivative (PID) method, where FLC is used to initialize the input of the PID method to find the quadcopter stability point. The application of fuzzy methods for the initial tuning of PID parameters has proven effective in enhancing the system's fundamental performance, such as overshoot, rise time, and settling time, compared to the conventional PID approach. The proposed method can reduce overshoot by over 20%, with reductions reaching up to 88% in yaw motion. Additionally, the Fuzzy-PID approach significantly improves stability, shortening the time to achieve steady-state by less than 1 seconds for all movements while PID did more than 2s for pitch and roll motions and over 1s for yaw motion. © 2024 IEEE.

关键词： Two term control systems

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Enhancing Search Efficiency: Analyzing Learning Mechanisms in Metaheuristics

Enhancing Search Efficiency: Analyzing Learning Mechanisms i...

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2024 International Conference on Information Technology and Computing, ICITCOM 2024

作者： Nurcahyadi, Teddy Blum, Christian Universitas Muhammadiyah Yogyakarta Mechanical Engineering Study Program Engineering Faculty Yogyakarta Indonesia Institut d'Investigació en Inielligència Artificial Consejo Superior de Investigaciones Científicas Barcelona Spain

ISBN: (纸本)9798350379839

Metaheuristics have evolved significantly in the last few decades. Nowadays, more complex problems and essential applications are emerging, requiring more powerful metaheuristics to handle them. This article analyzes the characteristics and performance of existing metaheuristics, with particular emphasis on their learning mechanisms. Several critical aspects for improvement are identified, and several promising future research areas are recommended. © 2024 IEEE.

关键词： Contrastive Learning

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The Improvement of Personal Service in the MSMEs Marketplace Using a Rank-Based Collaborative Filtering Approach

The Improvement of Personal Service in the MSMEs Marketplace...

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2022 International Conference on Electrical and Information Technology, IEIT 2022

作者： Lestari, Sri Yulmaini Aswin Sulyono Nul Fikri, Ruki Rizal Pratama, Yan Aditiya Informatics Engineering Study Program Faculty of Computer Science Lampung Bandar Indonesia Management Study Program Faculty of Business Economics Lampung Bandar Indonesia

ISBN: (数字)9781665453035

ISBN: (纸本)9781665453035

Indonesian MSMEs in 2022 will begin to enter the transformational recovery phase. Various preparations must be made in order to adapt. One that has been done is to increase the number of MSMEs entering the digital ecosystem, such as the MSME marketplace. The MSME Marketplace is used for marketing various MSME products online. The MSME Marketplace must be supported by methods that are able to provide good and fast personal services, considering the types and variety of products offered are increasing in number and varying from time to time. Therefore, this study proposes the Porat_Rank method to produce product recommendations that match user interests quickly so that users are served well. The experimental results show that the Porat_Rank method is superior to the Copelan Score method both in producing recommendations and in processing speed. © 2022 IEEE.

关键词： Collaborative filtering

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