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arXiv 2022年

作者： Krechetov, Mikhail Doctoral Program in Engineering Systems

The central object of this thesis is known under different names in the fields of computer science and statistical mechanics. In computer science, it is called the Maximum Cut problem, one of the famous twenty-one Karp’s original NP-hard problems, while the same object from Physics is called the Ising Spin Glass model. This model of a rich structure often appears as a reduction or reformulation of real-world problems from computer science, physics and engineering. However, solving this model exactly (finding the maximal cut or the ground state) is likely to stay an intractable problem (unless P = NP) and requires the development of ad-hoc heuristics for every particular family of instances. One of the bright and beautiful connections between discrete and continuous optimization is a Semidefinite programming-based rounding scheme for Maximum Cut. This procedure allows us to find a provably near-optimal solution;moreover, this method is conjectured to be the best possible in polynomial time. In the first two chapters of this thesis, we investigate local non-convex heuristics intended to improve the rounding scheme. In the last chapter of this thesis, we make one step further and aim to control the solution of the problem we wanted to solve in previous chapters. We formulate a bi-level optimization problem over the Ising model where we want to tweak the interactions as little as possible so that the ground state of the resulting Ising model satisfies the desired criteria. This kind of problem arises in pandemic modeling. We show that when the interactions are non-negative, our bi-level optimization is solvable in polynomial time using convex programming. Copyright © 2022, The Authors. All rights reserved.

关键词： Ising model

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Techniques for the Representation of the Application of Historical-Archaeological Evidence Scales in Heritage Assets

Techniques for the Representation of the Application of Hist...

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International Joint Conference on Mechanics, Design engineering and Advanced Manufacturing, JCM 2022

作者： Cáceres-Criado, Irene García-Molina, Diego Francisco Hidalgo-Fernández, Rafael Enrique Triviño-Tarradas, Paula Doctoral Program in Agricultural Food Forestry and Rural Development Engineering University of Córdoba Córdoba Spain Department of Graphic Engineering Design and Engineering Projects of the University of Jaen Jaen Spain Department of Graphic and Geomatics Engineering University of Cordoba Córdoba Spain

ISBN: (纸本)9783031159275

At the beginning of the discipline, archaeology as a scientific subject was understood thanks to the archaeological drawing, or what is the same, to the graphic representation of heritage. The use of new technologies in the scope of archaeology has posed a revolution in the representation of heritage assets. The creation of multi-disciplinary teams who transfer the information of the archaeological record to new representation techniques, and who can solve specific problems in the scope of heritage. Virtual archaeology contributes to the motivation and interest for the learning of archaeological spaces. In this context, new technologies are a relevant and more attractive tool that ease the access to the knowledge of past societies, facilitating the didactic and informational mission and the clarity and comprehension of the contents. This study is focused on the representation of the degree of historical-archaeological evidence of a heritage asset, through the use of the three evidence scale propositions that exist nowadays. Evidence scales will be compared, with the aim of obtaining accurate results of their application, identifying their suitability. Furthermore, compliance with the scientific quality requirements established for this kind of work will be guaranteed. Currently, it is important to disseminate the existing heritage, relying on emerging technologies. In the same way as the lifestyles of people change, the ways of acquiring information must also change. This study supports the creation of a unique language in the dissemination of archaeological remains relying on emerging technologies. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Evidence level Historical-archaeological evidence scale Reconstructive units Virtual reconstruction

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Real-Time Object Detection Performance of YOLOv8 Models for Self-Driving Cars in a Mixed Traffic Environment 2

Real-Time Object Detection Performance of YOLOv8 Models for ...

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2nd International Conference on Computer System, Information Technology, and Electrical engineering, COSITE 2023

作者： Afdhal, Afdhal Saddami, Khairun Sugiarto, Sugiarto Fuadi, Zahrul Nasaruddin, Nasaruddin Doctoral Program School of Engineering Universitas Syiah Kuala Indonesia Department of Electrical and Computer Engineering Universitas Syiah Kuala Indonesia Department of Civil Engineering Universitas Syiah Kuala Indonesia Department of Mechanical dan Industrial Engineering Universitas Syiah Kuala Indonesia Indonesia

ISBN: (纸本)9798350343069

Self-driving cars have gained significant attention in recent years. Real-time object detection is a critical component of their perception system. One of the main challenges in developing safe and efficient self-driving cars lies in accurately and in real-time detecting objects in diverse and complex traffic environments. This paper presents the performance evaluation of real-time object detection of YOLOv8 models, a state-of-the-art deep learning framework for self-driving cars in mixed traffic environments. The objective is to assess the extent of YOLOv8's object detection capabilities can be used for self-driving car within complex realworld traffic scenarios. The experimental results show that the accuracy of YOLOv8 during normal daylight scenarios ranges from 0.60 ~ 0.80. In contrast, the accuracy values obtained in night scenarios fall between 0.15 ~ 0.25. Similarly, the FMeasure of YOLOv8 models under daylight conditions ranges from 0.75 ~ 0.87. Conversely, the F-Measure in night conditions falls between 0.27 ~ 0.46. Based on our thorough evaluation results, YOLOv8 has demonstrated its robustness in detecting objects. However, the algorithm requires improvement to effectively handle the challenges of self-driving cars' object detection systems in mixed traffic, such as diverse object classifications, small-scale objects, fast-moving objects, blur, glare, and low-light illumination, particularly in nighttime scenarios. © 2023 IEEE.

关键词： Object detection

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Effect of Anode Surface Conditions on Heaterless Hollow Cathode Performance 74

Effect of Anode Surface Conditions on Heaterless Hollow Cath...

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74th International Astronautical Congress, IAC 2023

作者： Hsieh, Jordan H. Huang, Yi-Lung Li, She-Shen Huang, Ping-Han Li, Yueh-Heng Department of Aeronautics and Astronautics National Cheng Kung University Tainan70101 Taiwan International Doctoral Degree Program on Energy Engineering National Cheng Kung University Tainan70101 Taiwan

The study examines the effects of planar anode surface roughness on heaterless hollow cathode discharge characteristics. Three distinct roughness levels, Ra 1.6, Ra 3.2, and Ra 6.4, were achieved using a specialized machining procedure. A pivotal observation highlights the relationship between discharge voltage and the surface texture of the anode. As surface roughness intensifies, the planar anode demands a decreased discharge voltage to uphold the primary discharge. This phenomenon can be attributed to the increased surface area from roughness, promoting efficient electron current collection. Furthermore, oscillations in discharge voltage appear to be inversely proportional to the surface roughness of the planar anode, potentially tied to variations in the neutral gas density gradient near the anode and cathode. Such insights are instrumental for standardizing hollow cathode tests and set a foundation for more in-depth research in subsequent studies. Copyright © 2023 by the International Astronautical Federation (IAF). All rights reserved.

关键词： Anode Cathode Discharge Heaterless Surface

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DDPG-Based PID Optimal Controller for Position and Sway Angle of RTGC 23

DDPG-Based PID Optimal Controller for Position and Sway Angl...

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23rd International Conference on Control, Automation and Systems, ICCAS 2023

作者： Bandong, Steven Nazaruddin, Yul Y. Joelianto, Endra Institut Teknologi Bandung Engineering Physics Doctoral Program Faculty of Industrial Technology Bandung40132 Indonesia Instrumentation and Control Research Group Faculty of Industrial Technology Bandung40132 Indonesia

ISBN: (纸本)9788993215274

Increasing global trade requires fast and accurate container transfers by minimizing positional errors and swing angles on the Rubber Tyred Gantry Crane (RTGC) at the container yard causing that the optimization of the controller is a necessity. Currently developing artificial intelligence, namely reinforcement learning based Deep Deterministic Policy Gradient (DDPG) approach, can provide continuous action or output that can be used for controller optimization problems. DDPG can learn from its interactions with the environment, allowing it to identify the best optimal parameter region. This paper proposes DDPG as an PID controller optimizer for position and swing angle of RTGC tested on six episode variations and a trajectory reference. The results garnered from this proposed methodology reveal that the optimal PID parameters perform well across a spectrum of reference trajectories, as well as under varying system parameters such as container masses and rope lengths, as demonstrated by metrics like position and swing angle error, rise time, settling time, and overshoot. © 2023 ICROS.

关键词： Containers

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Investigation of Cylindrical Anode Diameter Influence on Hollow Cathode Operating Characteristics 74

Investigation of Cylindrical Anode Diameter Influence on Hol...

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74th International Astronautical Congress, IAC 2023

作者： Hsieh, Jordan H. Huang, Yi-Lung Huang, Ping-Han Wang, Wei-Cheng Li, Yueh-Heng Department of Aeronautics and Astronautics National Cheng Kung University Tainan70101 Taiwan International Doctoral Degree Program on Energy Engineering National Cheng Kung University Tainan70101 Taiwan

This research delves into the effects of cylindrical anode dimensions on the steady-state discharge of open-ended heaterless hollow cathodes. The study assessed anode diameters of 38 mm, 74 mm, and 102 mm. Challenges arose when utilizing the 102 mm diameter anode in diode mode, with a suspected divergent electric field stemming from the anode's size and closeness hindering consistent discharge between the cathode and anode. The cathode was set to operate in triode mode with the keeper adjusted to a discharge current of 1.2 A to navigate this impediment, ensuring the axial electric field's adequacy. In contrast, tests with 74 mm and 38 mm anodes were conducted in diode mode, with the keepers kept unpowered. Analysis of the I-V curves underscored a typical negative resistance in the cathode discharge, a phenomenon attributable to the diminishing emitter sheath voltage with elevating electron energy flux and emitter surface temperatures. A pronounced inverse correlation between the steady-state discharge current and gas flow rate was also discerned, connected to rising emitter temperatures and enhanced plasma drift resistance in the keeper orifice. Notably, anode diameter emerged as a determinant of current leakage, with the 74 mm anode presenting a reduced discharge voltage compared to the 38 mm due to augmented current leakage. Conversely, the 102 mm anode demanded a higher voltage, a requirement linked to its attenuated axial electric field, compelling a rise in voltage for a sufficient current draw to the anode power supply. These discoveries furnish understanding for refining open-ended heaterless hollow cathode designs and pave the way for subsequent inquiries into cathode plumes. Copyright © 2023 by the International Astronautical Federation (IAF). All rights reserved.

关键词： Anode Cathode Diameter Geometry Heaterless

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Impact of different kinds of biomass mixtures on combustion performance, interaction and synergistic effects in cofiring of coal and biomass in steam power plants

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Clean Energy 2023年第5期7卷 1136-1147页

作者： Mochamad Soleh Azaria Haykal Ahmad Firman Bagja Juangsa Prihadi Setyo Darmanto Ari Darmawan Pasek Mechanical Engineering Doctoral Program Study Faculty of Mechanical and Aerospace EngineeringInstitut Teknologi BandungJl.Ganesha 10Bandung40132 Indonesia Mechanical Engineering Master Program Study Faculty of Mechanical and Aerospace EngineeringInstitut Teknologi BandungJl.Ganesha 10Bandung40132 Indonesia Energy Conversion Research Group Faculty of Mechanical and Aerospace EngineeringInstitut Teknologi BandungJl.Ganesha 10Bandung40132 Indonesia Research Center for New and Renewable Energy Institut Teknologi BandungJl.Ganesha 10Bandung40132 Indonesia Research and Development Center PT.PLN Indonesia Power

The cofiring of biomass and coal may be one of the most effective methods to improve energy utilization efficiency and reduce greenhouse gas *** study aims to investigate combustion performance,interaction and synergistic effects in the cofiring of coal and three types of *** fuel consisting of coal and three types of biomass such as sawdust,rice husk and solid recovery fuel was selected as the research *** and proximate analysis and differential thermogravimetric analysis with heating rates of between 10°C and 40°C/minute are used to analyse combustion *** of combustion in a 600-MWe steam power plant with a Carolina-type boiler is also carried out with the help of computational fluid dynamic(CFD)analysis to see the effect of the interaction and synergy of the mixed fuel on the performance of the steam *** effect on the com-bustion process in the combustion chamber of a steam power plant is also *** on the analysis of several test results of parameters such as ignition temperature,burnout temperature,calorific value of the fuel mixtures as well as CFD simulation,the results of the study show a strong indication of a positive synergy in mixing some of these biomasses as compared with a fuel mix-ture consisting only of coal and one type of *** no power derating of the boiler occurs until the biomass content in the fuel mixture is~30%on a mass *** reduction in greenhouse gas emissions also appears significant from the results of the CFD simulation of this study,which is characterized by a decrease in the fraction of CO_(2) in flue gas from 21.5%for coal alone as fuel to 15.9%in the case of cofiring excluding the CO_(2) attributed to the biomass.

关键词： biomass sawdust cofiring coal-fired power plant combustion decarbonization computational fluids dynamic

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Operational interpretation of the Choi rank through exclusion tasks

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Physical Review A 2024年第5期110卷 L050601-L050601页

作者： Benjamin Stratton Chung-Yun Hsieh Paul Skrzypczyk Quantum Engineering Centre for Doctoral Training H. H. Wills Physics Laboratory and Department of Electrical & Electronic Engineering University of Bristol Bristol BS8 1FD United Kingdom H.H. Wills Physics Laboratory University of Bristol Tyndall Avenue Bristol BS8 1TL United Kingdom CIFAR Azrieli Global Scholars Program CIFAR Toronto Canada

The Choi state is an indispensable tool in the study and analysis of quantum channels. Considering a channel in terms of its associated Choi state can greatly simplify problems. It also offers an alternative approach to the characterization of a channel, with properties of the Choi state providing novel insight into a channel's behavior. The rank of a Choi state, termed the Choi rank, has proven to be an important characterizing property, and here, its significance is further elucidated through an operational interpretation. The Choi rank is shown to provide a universal bound on how successfully two agents, Alice and Bob, can perform an entanglement-assisted exclusion task. The task can be considered an extension of superdense coding, where Bob can only output information about Alice's encoded bit string with certainty. Conclusive state exclusion, in place of state discrimination, is therefore considered at the culmination of the superdense coding protocol. In order to prove this result, a necessary condition for conclusive k-state exclusion of a set of states is presented in order to achieve this result, and the notions of weak and strong exclusion are introduced.

关键词： Quantum channels Quantum communication, protocols & technology Quantum information processing Quantum information theory

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Experimental study of CO₂ utilization as a density modification agent for maximizing palm shells and kernels separation efficiency

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South African Journal of Chemical engineering 2022年 42卷 283-289页

作者： Muhammad, Muhammad Marwan, Marwan Munawar, Edi Zaki, Muhammad Doctoral Program School of Engineering Post Graduate Program Universitas Syiah Kuala Banda Aceh 23111 Indonesia Department of Chemical Engineering Faculty of Engineering Universitas Serambi Mekkah Banda Aceh 23245 Indonesia Department of Chemical Engineering Faculty of Engineering Universitas Syiah Kuala Banda Aceh 23111 Indonesia

In palm oil mills (POMs), the CO2 generated from palm oil processing activities is immediately discharged into the atmosphere, increasing greenhouse gases (GHGs) emissions. CO2 utilization can be viewed as a strategy ... 详细信息

In palm oil mills (POMs), the CO₂ generated from palm oil processing activities is immediately discharged into the atmosphere, increasing greenhouse gases (GHGs) emissions. CO₂ utilization can be viewed as a strategy for minimizing GHGs emissions and replacing CaCO₃, frequently used as a density modification agent in the POMs. This research aimed to formulate a novel separation fluid for separating palm shells and kernels by utilizing CO₂ as a density modification agent. Monoethanolamine (MEA) was selected as a chemical absorbent in this study. Chemisorption was applied to ensure that CO₂ was permanently absorbed into the solution. The MEA mass fraction was varied with ratios of 10, 20, 30, 40, and 50 % w/w. Then, the separation efficiency of the palm shells and kernels was measured by adding 15 % w/w of the mixture of palm shells and kernels into the formulated fluid. It was done based on the density difference between palm shells and kernels. The results showed that the optimal separation fluid density ranged between 1.1086 to 1.1777 g/cm³ at an MEA ratio of 30–50% w/w. It corresponds to the maximum separation efficiency of palm shells and kernels, which ranged from 97 to 100 %. This research indicated that CO₂ could be utilized as a density modification agent in the separation fluid. As a result, the formulated fluid was suitable for separating palm shells and kernels while also reducing GHG emissions in POMs by CO₂ utilization. © 2022

关键词： CO2 utilization Density modification agent GHGs emissions Palm shells–kernels separation Separation fluid

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State of the Art: Fragility Function of Electrical Power System 6

State of the Art: Fragility Function of Electrical Power Sys...

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6th International Seminar on Research of Information Technology and Intelligent Systems, ISRITI 2023

作者： Sahnur Nasution, Elvy Syahrial, Syahrial Devi Sara, Ira Away, Yuwaldi Postgraduate School of Engineering Universitas Syiah Kuala Universitas Muhammadiyah Sumatera Utara Doctoral Program Banda Aceh23111 Indonesia Universitas Syiah Kuala Dept. Electrical and Computer Engineering Banda Aceh23111 Indonesia

ISBN: (纸本)9798350358346

Natural disasters, particularly earthquakes, can cause the electric power system to collapse, which can be brought on by one of the infrastructure breakdowns in the power system. Damaged power system can cause losses to electricity providers, electricity users, so it is necessary to understand the vulnerability of electric power system assets to earthquakes. The research fragility function presents the concept of fragility function in power system of the entire power system, showed fragility of power plant, transmission line, tower transmission, transformers, generator, and substation. Substation is more fragile than the others because substation consist of circuit breaker and disconnecting switch the most fragile asset. In addition, this paper also presents how to creating the fragility function and several solutions to increase the resilience of the electric power system to earthquakes. © 2023 IEEE.

关键词： Earthquakes

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