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The rapid development of digital economy has led to the emergence of various black and shadow internet industries, which pose potential risks that can be identified and managed through digital risk management (DRM) that uses different techniques such as machine learning and deep learning. The evolution of DRM architecture has been driven by changes in data forms. However, the development of AI-generated content (AIGC) technology, such as ChatGPT and Stable Diffusion, has given black and shadow industries powerful tools to personalize data and generate realistic images and conversations for fraudulent activities. This poses a challenge for DRM systems to control risks from the source of data generation and to respond quickly to the fast-changing risk environment. This paper aims to provide a technical analysis of the challenges and opportunities of AIGC from upstream, midstream, and downstream paths of black/shadow industries and suggest future directions for improving existing risk control systems. The paper will explore the new black and shadow techniques triggered by generative AI technology and provide insights for building the next-generation DRM system.

Traffic signal control is one of the most cost-effective approaches to mitigating traffic congestion. In practice, before implementing a new signal system, traffic signal simulation is usually performed to estimate the impact of the proposed solution. In other words, microsimulation tools provide a huge amount of output results that can be used for the performance assessment of signal control systems. To mimic the real-time signal operations, microscopic traffic simulation is typically adopted in traffic signal simulation, aiming to model the individual vehicle movements on a second or sub-second basis. Traffic signal simulation is in many aspects different than traditional traffic simulation. First, traffic signal simulation has to involve a signal system that configures the signal phasing and timing plan. Such signal systems could be established on top of a very simple two-phase setting or a complicated NEMA eight-phase setting depending on the purpose of the simulation. Second, signal simulation has to take into account the special features of real-world signal controllers, such as transit signal priority, signal preemption, and so on. Sometimes an advanced software-in-the-loop simulation is preferred. Third, signal simulation usually integrates vehicles with signals, enabled by connected vehicles v2i technology. New technologies such as SPat and BSM, shall be considered in the traffic signal simulation. This cookbook aims to provide the traffic signal community with easy-to-follow procedures and examples in conducting different aspects of traffic signal simulation. This cookbook is a collection of tiny simulation “recipes” that each demonstrates a particular signal control concept. The use of this book will aid in the consistent and reproducible application of traffic signal microsimulation models and will further encourage the development of signal control algorithms by the entire community. As a result, practitioners and researchers will be equipped to conduct quick signal-related simulations. Depending on the project-specific purpose, need, and scope, elements of the process described in this cookbook may be enhanced or adapted to support the decision-makers. It is strongly recommended that the respective stakeholders and partners consult prior to and throughout the application of any signal simulation model., The authors were gathered through the traffic signal committee (ACP 25) of the Transportation Research Board (TRB). But this report is NOT a publication of TRB.

background: Osteoporosis is an important cause of bone fractures and even a cause of threaten to the lives of elderly people. Mind-body exercises are beneficial interventions for improving flexibility, controlling body balance, and reducing pain. To assess the effect of mind-body exercise on osteoporosis in aging people, we will perform this systematic review. Methods: Randomized controlled trials (RCTs) which carried out about mind-body exercise for osteoporosis will be included. Web of Science, PubMed, Science Direct, Medline, Cochrane Library, China National Knowledge Infrastructure, and Wanfang will be searched from inception to January 2020. The outcomes will include bone mineral density (BMD), bone mineral content (BMC), body balance, function of lower extremity, pain, fearing level, and quality of life. Trial reporting quality will be assessed by 2 reviewers independently and Review Manager 5.3 software will be used for meta-analysis. Trial registration is under PROSPERO (CRD42020165385). Results: Based on the current evidence, the potential rank of the efficacy and safety of mind-body exercises for BMD, BMC, body balance, function of lower extremity, pain, fearing level and quality of life will be assessed, and a prioritization regimen will be summarized. Conclusions: Evidence from this systematic review could be useful for patients, clinical practitioners, and guideline-makers to select an optimum proposal of mild-body exercises for older adults with osteoporosis.

Exploration efficiency challenges for multi-agent reinforcement learning (MARL), as the policy learned by confederate MARL depends on the interaction among agents. Less informative reward also restricts the learning speed of MARL in comparison with the informative label in supervised learning. This paper proposes a novel communication method which helps agents focus on different exploration subarea to guide MARL to accelerate exploration. We propose a predictive network to forecast the reward of current state-action pair and use the guidance learned by the predictive network to modify the reward function. An improved prioritized experience replay is employed to help agents better take advantage of the different knowledge learned by different agents. Experimental results demonstrate that the proposed algorithm outperforms existing methods in cooperative multi-agent environments.

The Green Light SONATA project originated with a hunch in the engineering domain, but could only materialize through true collaboration of researchers working across disciplines. The project tested the hypothesis that translating simulated traffic information into music could lead to musical resolution of persistent traffic congestion. Our team—consisting of civil engineers, a composer/performer/computer music researcher, and an ethnomusicologist—proceeded to construct a model of an intersection in which each direction of traffic flow was assigned a musical pitch. Hearing these pitches as cues, musicians could interact with the sonified traffic to allow vehicles to proceed through the intersection. The result was a musical “gamification” of traffic flow in which the goal was to minimize the vehicles’ idle time. The next stage of this project will include public demonstration and testing sessions, involving students and additional musicians, to assess the concept’s viability, refine our methods, and gather further data. The team’s multidisciplinary dialogue takes us on productive tangents translating between different domains of musical and technical expertise. Moving forward, we plan to test additional methods of data sonification, manipulating additional musical variables (including pulse and rhythm, sequence, scales, ornaments, and other musical elements) and scaling up to model multiple consecutive intersections.

This dissertation aims to reduce urban traffic congestion with street traffic signal control. The traffic signal controllers in the U.S. follow the National Electrical Manufacturing Association Standards (NEMA Standards). In a NEMA controller, the control parameters for a coordinated control are cycle, green splits, and offset. This dissertation proposed a virtual phase-link concept and developed a macroscopic model to describe the dynamics of a traffic network. The coordinated optimal splits control problem was solved using model predictive control. The outputs of the solution are the green splits that can be used in NEMA controllers. I compared the proposed method with a state-of-the-practice signal timing software under coordinated-actuated control settings. It was found that the proposed method significantly outperformed the benchmarking method. I compared the proposed NEMA-based virtual phase-link model and a Max Pressure controller model using Vissim. It was found that the virtual phase-link method outperformed two control strategies and performed close, but not as good as, the Max Pressure control strategy. The disadvantage of the virtual phase-link method stemmed from the waste of green time during a fixed control cycle length and the delay which comes from the slowing down of platoon during a road link to allow vehicles to switch lanes. Compared to the Max Pressure control strategy, the virtual phase-link method can be implemented by any traffic controller that follows the NEMA standards. The real-time requirement of the virtual phase-link method is not as strict as the Max Pressure control strategy. I introduced the offsets optimization into the virtual phase-link method. I modeled the traffic arrival pattern based on the optimization results from the virtual phase-link control method. I then derived a phase delay function based on the traffic arrival pattern. The phase delay function is a function of the offset between two consecutive intersections. This phase delay function was then used for offsets optimization along an arterial. I tested the offsets optimization method against a base case using microscopic simulations. It was found that the proposed offset optimization method can significantly reduce vehicle delays. Doctor of Philosophy The goal of this work is to reduce traffic congestion by providing optimized signal timing plans to controllers. Knowing that the controllers in the U.S. follow National Electrical Manufacturing Association (NEMA) Standards, I proposed a virtual phase-link concept and modeled the road traffic network under NEMA controllers’ control as a set of virtual phase-links. Each virtual phase-link corresponds to a NEMA phase at an intersection. I then proposed a NEMA-based virtual phase-link street traffic model. The control variables are the green time allocated to each phase. I compared the proposed NEMA-based virtual phase-link control method with a state-of-the-practice signal timing software using simulation experiments. It was found that the proposed control methods significantly outperformed the signal timing software. I implemented a state-of-the-art adaptive control strategy, Max Pressure control. I compared the proposed NEMA-based virtual phase-link control method with the Max Pressure control strategy. I found that the virtual phase-link control method performed close, but not as good as, the Max Pressure control strategy. The disadvantage of the virtual phase-link method stemmed from the waste of green time during a fixed control cycle length and the delay which comes from the slowing down of platoon during a road link to allow vehicles to switch lanes. The Max Pressure control needs non-conventional controllers which can potentially switch to any phase at any time. Compared to the Max Pressure control strategy, the virtual phase-link method can be implemented by any traffic controller that follows the NEMA standards. The real-time requirement of the virtual phase-link method is not as strict as the Max Pressure control strategy. I then augmented the virtual phase-link method with optimal offsets control. The offsets are the time differences of the coordinated phases comparing to a reference point in a control cycle. I derived a phase delay function and used that function to optimize the offsets by minimizing the associated delays. The simulation experiments showed that the proposed offsets optimization method could reduce the delay along the coordinated path significantly.

The subject on convergence analysis of optimization methods is an importantarea in optimization theory. However, convergence is not sufficient as a criterion forcomparing the efficiency of different algorithms. Therefore, we need another theoryto measure the difficulty of optimization problems and the efficiency of optimizationalgorithms. This theory is called complexity analysis theory of optimizationalgorithms.This paper is divided into five parts. The first section introduces the basic setups of complexity analysisframeworks, gives the definition, methods and examples of complexity analysis,and summarizes the complexity results. In the secondsection, the complexity analysis for the smooth optimization problem is introduced.We give the upper and lower complexity bounds for different optimization problems,and also introduce the framework of convergence analysis for the accelerated gradientmethod. In the third section, the upper bounds of the complexity of nonsmoothoptimization problems are introduced. We present the complexity analysisfor the subgradient method, the mirror descent method, the center-of-gravity method,and the ellipsoid method. In the fourth section, we introduce the complexity analysis for theconditional gradient method, study its upper and lower bounds of complexity andpresent the framework of the acceleratedconditional gradient method. In the fifth section, we introduce the complexity analysisof the stochastic optimization algorithm, and compare the confidence level for theconvergence under convex and nonconvexsettings.

Exploration efficiency is a challenging problem in multi-agent reinforcement learning (MARL), as the policy learned by confederate MARL depends on the collaborative approach among multiple agents. Another important problem is the less informative reward restricts the learning speed of MARL compared with the informative label in supervised learning. In this work, we leverage on a novel communication method to guide MARL to accelerate exploration and propose a predictive network to forecast the reward of current state-action pair and use the guidance learned by the predictive network to modify the reward function. An improved prioritized experience replay is employed to better take advantage of the different knowledge learned by different agents which utilizes Time-difference (TD) error more effectively. Experimental results demonstrates that the proposed algorithm outperforms existing methods in cooperative multi-agent environments. We remark that this algorithm can be extended to supervised learning to speed up its training., Comment: Theequations (7)-(10) in the paper are incorrectly derived, and need to be withdrawn and revised in many places

Transportation engineering is a wide area that covers different topics including traffic planning, highway design, pavement design, traffic safety, and traffic control. Certain concepts in those topics are challenging and are hard to understand based on textbooks and lectures. In this work, we developed five web games targeting the five topics in transportation engineering education to improve students’ understanding of those hard concepts. The games are hosted in a website server. Students can play these games online after register and login. The server stores the users’ information and their gameplay data. We conducted a Before-and-After study to test the effectiveness of the games in terms of improving the learning outcomes of the students. The results showed that the games could increase the students’ understanding of hard concepts significantly. The developed games can be used in transportation education. This game framework can serve as a reference for other education game developers. We envision that more educational games will be developed by transportation and education communities in the recent future. There will be more than one game for the same topic. We need an approach to select games for different students group. We proposed a gravity model for evaluating the engagement of the students for the educational games. We found that different games have different properties in terms of attracting students’ engagement. The proposed model can be used in the future for selecting educational games for specific students group. Master of Science This thesis presents the effort of making computer games for education purpose. I developed five games corresponding to the five areas in transportation engineering courses. The objective of this work is to let the students understand the hard concepts in transportation engineering by playing the developed games. The students can play the games online, and their gameplay data will be recorded as they play. The effectiveness of this work was tested using before-and-after quizzes. We designed a set of quizzes that are within transportation engineering and can be solved using the knowledge learned in the games. We asked the students to do the quizzes and, without any feedback, do the same quizzes again after playing the games. The result showed that their scores improved in general, which means their understanding of transportation engineering was improved. Using the data collected from the gameplay, quizzes, and the students’ course scores, I proposed a gravity model that describes how students were engaged in the games. I found that different games could attract different students.

In this paper, the Dynaform numerical method was used to simulate the deep drawing process of the cylindrical parts. The distribution of the thickness, stress and strain of the cylindrical part during multi-stage deep drawing, as well as the possible defects of the cylindrical parts at this time, were compared without using blank holder, using the flat blank holder or using cone-shaped blank holder. The one-step drawing showed that the use of flat blank holder or cone-shaped blank holder didn't have too much difference in stress and strain distribution. Based on the one-step drawn part, the stress and strain under different conditions at the second-step drawing showed that the use of cone-shaped blank holder could prevent the wrinkling and crack of the work-piece. The numerical simulation technologies presented in this paper can be used in the early analysis of such a complex process during the mold design, so as to predict and control the possible defects in the process of material processing, which can be used as a reference to verify the reliability of mold design.

According to differences of the protolith formations, the early Precambrian strata in the northern part of the North China platform may be divided into the stable stratigraphic region in the west and the mobile stratigraphic region in the east. Based on unconformities, either stratiragphic or tectonic, as well as significant metamorphic thermal events, the two regions may be stratigraphically defined as follows: 1) the middle Archaean Fuping Supergroup composed of the Chenzhuang and Wanzi Groups (stable areas), and the middle Archaean Qianxi Group (mobile area), whose upper limits are all dated at 2800 Ma; and 2) the upper Archaean Wutai Supergroup composed of the Longquanguan, Shizui and Taihuai Groups (stable areas), and the upper Archaean Zunhua, Dantazi and Zhuzhangzi Groups (mobile areas), whose upper limits are all dated at 2500 Ma. A correlation of the above-mentioned units is also made. The lower Proterozoic Hutuo Group of the stable region is adjusted to comprise the Gaofan, Doucun, Dongye and Guojiazhai Groups. The upper limit of the Gaofan Group is placed at 2350 Ma, Dongye 1850 Ma and Guojiazhai (the lower limit of the Changcheng System) 1700 Ma.

The inland river channel is narrow, especially in the ferry areas, where urgent situation between ferry and waterway shipping will happen from time to time, if the risk of collision between vessels could be found in time, the inland waterway will be smooth. Traditional method to ensure the risk of collision exists abuse in the inland river, basing on the principle of robot velocity obstacle method, this article presents a new algorithm to assure the risk of collision, which could be used for confirmation of the risk of collision and collision avoidance path planning. Through the simulation experiment, it shows that the method is practical in the region of the ferry and the judgment of the risk of collision as well as the collision avoidance path planning.

High impedance surface, due to its unique property of in-phase reflection at some frequency, could be used in designing multiband Salisbury screen by replacing the metallic ground plane in a traditional structure, which is proposed, in this paper, to enhance the microwave absorbing performance of the conventional Salisbury screen. First, electromagnetic wave field intensity of different frequency in space after being reflected by a high impedance surface is analyzed, which implies that new absorption bands can be introduced at about the frequencies of in-phase reflection by sharing Salisbury screen’s resistive sheet, without adding extra lossy materials such as lumped elements or others. Then, by taking a single band high impedance surface at 6.25 GHz and a dual-band high impedance surface at 6.27 and 8.17 GHz, which are both composed of patches array with varying periodic size and a thickness of 0.6 mm, the multiband Salisbury screens can be constructed utilizing a conventional one with an absorbing peak at about 10.5 GHz. The reflectivity of these multiband absorbers are simulated by employing the commercial CST microwave studio and later measured using a reflectivity measurement system comprising two polarized horns and a vector network analyzer. Experimental results agree well with the simulations, and all results verify that the method presented at the beginning is effective. Results also show that new additional absorptions appear at the frequencies where microwaves are nearly reflected in phase from the high impedance surface, with the same number of the in-phase reflection bands. Meanwhile, the original microwave absorbing capability of the traditional Salisbury screen is reserved mostly. Compared to the single band high impedance surface, the dual-band high impedance surface performs better in the design as the absorbing bandwidth is wider and the absorbing frequency is lower. With an additional thickness of the high impedance surface (no more than 1 mm), the total absorption bandwidth of the multiband Salisbury screen with a reflection below -10 dB increases from 8.5 to 10.1 GHz, and the lowest frequency with 10 dB absorption falls from 7.5 to 5.98 GHz. So it could be concluded that the design of multiband Salisbury screen is helpful to widen the absorption, especially towards the lower frequency direction.