Pub Date : 2024-11-24DOI: 10.1016/j.simpat.2024.103044
Hang Yu, Xintong Li, Weiguo Song, Jianlin Li, Xuehua Song, Jun Zhang
In recent years, there has been a growing focus on the study of interactive movements within mixed crowds in the field of pedestrian evacuation. This study examines a specific type of interaction within mixed crowd: Group A chases Group B, while Group B needs to evade Group A and complete an evacuation, such as in situations involving attackers and pedestrians during a sudden violent incident. To model these complex movements, a velocity-based model incorporating panic propagation is developed. In this model, pedestrians adjust the magnitude and direction of their velocity by taking into account three key factors: avoidance of the attacker, movement toward the exit, and herd mentality. After a detailed introduction of the model, we first simulated and analyzed the parameters in the model to investigate the impact of various factors on the number of casualties and evacuation time. Subsequently, collective behavior from nature, experimental data, and specific crowd movement data are utilized to compare simulation results and validate the accuracy of the model. Finally, through simulations of single-exit and dual-exit bottleneck scenarios, a comparison of casualties revealed that placing exits at the corners of walls in building designs is more conducive to pedestrian evacuation.
{"title":"A mixed crowd movement model incorporating chasing behavior","authors":"Hang Yu, Xintong Li, Weiguo Song, Jianlin Li, Xuehua Song, Jun Zhang","doi":"10.1016/j.simpat.2024.103044","DOIUrl":"10.1016/j.simpat.2024.103044","url":null,"abstract":"<div><div>In recent years, there has been a growing focus on the study of interactive movements within mixed crowds in the field of pedestrian evacuation. This study examines a specific type of interaction within mixed crowd: Group A chases Group B, while Group B needs to evade Group A and complete an evacuation, such as in situations involving attackers and pedestrians during a sudden violent incident. To model these complex movements, a velocity-based model incorporating panic propagation is developed. In this model, pedestrians adjust the magnitude and direction of their velocity by taking into account three key factors: avoidance of the attacker, movement toward the exit, and herd mentality. After a detailed introduction of the model, we first simulated and analyzed the parameters in the model to investigate the impact of various factors on the number of casualties and evacuation time. Subsequently, collective behavior from nature, experimental data, and specific crowd movement data are utilized to compare simulation results and validate the accuracy of the model. Finally, through simulations of single-exit and dual-exit bottleneck scenarios, a comparison of casualties revealed that placing exits at the corners of walls in building designs is more conducive to pedestrian evacuation.</div></div>","PeriodicalId":49518,"journal":{"name":"Simulation Modelling Practice and Theory","volume":"138 ","pages":"Article 103044"},"PeriodicalIF":3.5,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-23DOI: 10.1016/j.simpat.2024.103042
Charafeddine Mechalikh , Abd El Heq Silem , Zahra Safavifar , Fatemeh Golpayegani
Edge computing, by pushing resources closer to the network’s edge, is revolutionizing data processing, enabling real-time analysis and localized decision-making on resource-constrained devices. However, designing and validating innovative solutions within this dynamic environment presents significant challenges.
While numerous edge simulators exist, their shortcomings often restrict researchers’ ability to address their research questions. Many of them serve specific use cases (e.g., small scale scenarios, static application placement, etc.), lacking the breadth and flexibility needed for diverse research requirements. Furthermore, the lack of benchmarking studies complicates the process of selecting the right simulators for a specific need.
This study addresses these limitations by presenting a comprehensive evaluation of 24 edge computing simulators, filling a critical gap in the literature. We propose a robust methodology that assesses the simulators based on functionality, maintenance, scalability, reliability, efficiency, and usability. Our study provides clear classifications and comparisons of the simulators to assist researchers in selecting the most suitable one for their edge computing scenarios. Additionally, we identify and discuss opportunities and challenges for advancing the current state of the art in edge simulation, highlighting potential areas for future research.
{"title":"Quality matters: A comprehensive comparative study of edge computing simulators","authors":"Charafeddine Mechalikh , Abd El Heq Silem , Zahra Safavifar , Fatemeh Golpayegani","doi":"10.1016/j.simpat.2024.103042","DOIUrl":"10.1016/j.simpat.2024.103042","url":null,"abstract":"<div><div>Edge computing, by pushing resources closer to the network’s edge, is revolutionizing data processing, enabling real-time analysis and localized decision-making on resource-constrained devices. However, designing and validating innovative solutions within this dynamic environment presents significant challenges.</div><div>While numerous edge simulators exist, their shortcomings often restrict researchers’ ability to address their research questions. Many of them serve specific use cases (e.g., small scale scenarios, static application placement, etc.), lacking the breadth and flexibility needed for diverse research requirements. Furthermore, the lack of benchmarking studies complicates the process of selecting the right simulators for a specific need.</div><div>This study addresses these limitations by presenting a comprehensive evaluation of 24 edge computing simulators, filling a critical gap in the literature. We propose a robust methodology that assesses the simulators based on functionality, maintenance, scalability, reliability, efficiency, and usability. Our study provides clear classifications and comparisons of the simulators to assist researchers in selecting the most suitable one for their edge computing scenarios. Additionally, we identify and discuss opportunities and challenges for advancing the current state of the art in edge simulation, highlighting potential areas for future research.</div></div>","PeriodicalId":49518,"journal":{"name":"Simulation Modelling Practice and Theory","volume":"138 ","pages":"Article 103042"},"PeriodicalIF":3.5,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1016/j.simpat.2024.103041
Mei-Ling Wu, Jin-Yu Wu
This research investigates the advanced applications of Fan-Out Package-on-Package (FOPoP) technology within heterogeneous integration, highlighting its critical role in artificial intelligence (AI), big data analytics, and 5 G communication systems. Heterogeneous integration technology, which merges diverse components and technologies into a single package, is essential for addressing the increasing demands of modern electronic systems. However, wafer warpage during the FOPoP manufacturing process poses a significant challenge, impacting yield, chip alignment, and handling. We employ Finite Element Analysis (FEA) to tackle this issue using the element birth and death technique for process-oriented simulations. Our method innovatively utilizes both the backside and frontside Redistribution Layer (RDL) to create vertical interconnections within the FOPoP structure. The simulation process includes 11 stages: backside RDL electroplating, Polyimide (PI) curing, Molding Compound (MC) curing, frontside RDL electroplating, and PI curing. Comparing the simulated FOPoP wafer warpage values at each stage with experimental data, we consistently found discrepancies under 10 %, validating the accuracy of our simulations. Additionally, we identify effective strategies to reduce FOPoP wafer warpage through parameter analysis, such as lowering copper trace density in the RDL and increasing the die area ratio, thereby improving manufacturing yield. This research advances the understanding of FOPoP technology in heterogeneous integration and provides a robust framework for its application in next-generation electronic systems.
{"title":"Advanced FOPoP technology in heterogeneous integration: Finite element analysis with element birth and death technique","authors":"Mei-Ling Wu, Jin-Yu Wu","doi":"10.1016/j.simpat.2024.103041","DOIUrl":"10.1016/j.simpat.2024.103041","url":null,"abstract":"<div><div>This research investigates the advanced applications of Fan-Out Package-on-Package (FOPoP) technology within heterogeneous integration, highlighting its critical role in artificial intelligence (AI), big data analytics, and 5 G communication systems. Heterogeneous integration technology, which merges diverse components and technologies into a single package, is essential for addressing the increasing demands of modern electronic systems. However, wafer warpage during the FOPoP manufacturing process poses a significant challenge, impacting yield, chip alignment, and handling. We employ Finite Element Analysis (FEA) to tackle this issue using the element birth and death technique for process-oriented simulations. Our method innovatively utilizes both the backside and frontside Redistribution Layer (RDL) to create vertical interconnections within the FOPoP structure. The simulation process includes 11 stages: backside RDL electroplating, Polyimide (PI) curing, Molding Compound (MC) curing, frontside RDL electroplating, and PI curing. Comparing the simulated FOPoP wafer warpage values at each stage with experimental data, we consistently found discrepancies under 10 %, validating the accuracy of our simulations. Additionally, we identify effective strategies to reduce FOPoP wafer warpage through parameter analysis, such as lowering copper trace density in the RDL and increasing the die area ratio, thereby improving manufacturing yield. This research advances the understanding of FOPoP technology in heterogeneous integration and provides a robust framework for its application in next-generation electronic systems.</div></div>","PeriodicalId":49518,"journal":{"name":"Simulation Modelling Practice and Theory","volume":"138 ","pages":"Article 103041"},"PeriodicalIF":3.5,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-19DOI: 10.1016/j.simpat.2024.103043
Zhiliang Wang , Yu Ni , Jianguo Wang , Songyu Li
Through a series of numerical simulations on single-hole blasting and presplit blasting, this paper analyzed the performance differences of the Riedel-Hiermaier-Thomal (RHT) and Holmquist-Johnson-Cook (HJC) constitutive models in simulating the blasting crack propagation of rock under different in-situ stress environments. Firstly, the RHT model parameters for granite were determined through mechanical experiments. Then, the traditional HJC model was improved by introducing failure criterion, and the practicability of the above two models in simulating blasting cracks was verified. Finally, the performance differences between these two models were analyzed in simulating blasting cracks of deep rocks. The results indicate that the improved HJC model is consistent with the RHT model in characterizing the blasting cracks of shallow rock. As the burial depth increases, the RHT model can accurately simulate the propagation of cracks in the entire blasting area under different in-situ stress conditions, while the improved HJC model can only simulate the crushed zone generated by blasting well. In addition, the improved HJC model behaves poorly in terms of general applicability because the specific failure criterion cannot be applied to multiple scenarios. These findings can offer valuable references to deep rock blasting simulations.
{"title":"Improvement and performance analysis of constitutive model for rock blasting damage simulation","authors":"Zhiliang Wang , Yu Ni , Jianguo Wang , Songyu Li","doi":"10.1016/j.simpat.2024.103043","DOIUrl":"10.1016/j.simpat.2024.103043","url":null,"abstract":"<div><div>Through a series of numerical simulations on single-hole blasting and presplit blasting, this paper analyzed the performance differences of the Riedel-Hiermaier-Thomal (RHT) and Holmquist-Johnson-Cook (HJC) constitutive models in simulating the blasting crack propagation of rock under different in-situ stress environments. Firstly, the RHT model parameters for granite were determined through mechanical experiments. Then, the traditional HJC model was improved by introducing failure criterion, and the practicability of the above two models in simulating blasting cracks was verified. Finally, the performance differences between these two models were analyzed in simulating blasting cracks of deep rocks. The results indicate that the improved HJC model is consistent with the RHT model in characterizing the blasting cracks of shallow rock. As the burial depth increases, the RHT model can accurately simulate the propagation of cracks in the entire blasting area under different in-situ stress conditions, while the improved HJC model can only simulate the crushed zone generated by blasting well. In addition, the improved HJC model behaves poorly in terms of general applicability because the specific failure criterion cannot be applied to multiple scenarios. These findings can offer valuable references to deep rock blasting simulations.</div></div>","PeriodicalId":49518,"journal":{"name":"Simulation Modelling Practice and Theory","volume":"138 ","pages":"Article 103043"},"PeriodicalIF":3.5,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-16DOI: 10.1016/j.simpat.2024.103037
Sudeep Singh Sanga, Nidhi
This study focuses on a finite queueing model with multiple servers, incorporating an admission control F-policy and considerations for customers’ balking and server breakdown. The F-policy concept is used to control the flow of incoming customers, making the model formulation more realistic. Implementing the admission control F-policy, along with adding additional servers, can effectively alleviate congestion issues for customers by reducing the formation of queues and decreasing the frequency of customers opting out of the queue due to extended waiting time. In order to conduct a mathematical analysis of the model and establish probability distributions, we formulate the steady-state Chapman–Kolmogorov (C–K) equations and solve them using a recursive technique. The probability distributions allow us to develop several system performance measures, including the expected system size, the expected number of busy permanent servers, the probability of server breakdown, etc. These measures are utilized to assess the effectiveness of the model. The impact of system input parameters on several performance measures in the multi-server queueing model is presented using a numerical example. The accuracy of the results of performance measures is validated by implementing the adaptive neuro-fuzzy inference system (ANFIS) approach, enhancing the reliability and robustness of the findings. The non-linear cost function is also created to compute the optimal values of the decision variables, including the number of permanent servers, admission control threshold, service rate, and joining probabilities of customers. Grey wolf optimization (GWO) and particle swarm optimization (PSO) algorithms are applied to deal with the cost optimization problem. A comparative study of the GWO and PSO algorithms for cost optimization is also conducted. This optimization enables decision-makers to efficiently manage the system’s operations and resources. The findings of the study suggest that the proposed model can be applied in diverse real-life scenarios, such as electric vehicle charging stations (EVCSs), restaurants, and various other locations.
本研究的重点是具有多个服务器的有限队列模型，其中纳入了准入控制 F 政策，并考虑了客户逡巡和服务器故障等因素。F 政策概念用于控制进入的客户流，使模型的表述更加真实。实施准入控制 F 政策并增加服务器，可有效缓解客户拥堵问题，减少队列的形成，降低客户因等待时间延长而选择退出队列的频率。为了对模型进行数学分析并建立概率分布，我们提出了稳态 Chapman-Kolmogorov (C-K) 方程，并使用递归技术对其进行求解。通过概率分布，我们可以得出多个系统性能指标，包括预期系统规模、预期繁忙永久服务器数量、服务器崩溃概率等。我们利用这些指标来评估模型的有效性。通过一个数值示例介绍了系统输入参数对多服务器队列模型中若干性能指标的影响。通过采用自适应神经模糊推理系统（ANFIS）方法，验证了性能指标结果的准确性，从而提高了研究结果的可靠性和鲁棒性。此外，还创建了非线性成本函数来计算决策变量的最优值，包括永久服务器数量、准入控制阈值、服务速率和客户加入概率。灰狼优化（GWO）和粒子群优化（PSO）算法被用于处理成本优化问题。此外，还对成本优化的 GWO 和 PSO 算法进行了比较研究。这种优化使决策者能够有效地管理系统的运行和资源。研究结果表明，所提出的模型可应用于各种实际场景，如电动汽车充电站（EVCS）、餐厅和其他各种场所。
{"title":"Cost optimization and ANFIS computing for M/M/(R+c)/N queue under admission control policy and server breakdown","authors":"Sudeep Singh Sanga, Nidhi","doi":"10.1016/j.simpat.2024.103037","DOIUrl":"10.1016/j.simpat.2024.103037","url":null,"abstract":"<div><div>This study focuses on a finite queueing model with multiple servers, incorporating an admission control <em>F</em>-policy and considerations for customers’ balking and server breakdown. The <em>F</em>-policy concept is used to control the flow of incoming customers, making the model formulation more realistic. Implementing the admission control <em>F</em>-policy, along with adding additional servers, can effectively alleviate congestion issues for customers by reducing the formation of queues and decreasing the frequency of customers opting out of the queue due to extended waiting time. In order to conduct a mathematical analysis of the model and establish probability distributions, we formulate the steady-state Chapman–Kolmogorov (C–K) equations and solve them using a recursive technique. The probability distributions allow us to develop several system performance measures, including the expected system size, the expected number of busy permanent servers, the probability of server breakdown, etc. These measures are utilized to assess the effectiveness of the model. The impact of system input parameters on several performance measures in the multi-server queueing model is presented using a numerical example. The accuracy of the results of performance measures is validated by implementing the adaptive neuro-fuzzy inference system (ANFIS) approach, enhancing the reliability and robustness of the findings. The non-linear cost function is also created to compute the optimal values of the decision variables, including the number of permanent servers, admission control threshold, service rate, and joining probabilities of customers. Grey wolf optimization (GWO) and particle swarm optimization (PSO) algorithms are applied to deal with the cost optimization problem. A comparative study of the GWO and PSO algorithms for cost optimization is also conducted. This optimization enables decision-makers to efficiently manage the system’s operations and resources. The findings of the study suggest that the proposed model can be applied in diverse real-life scenarios, such as electric vehicle charging stations (EVCSs), restaurants, and various other locations.</div></div>","PeriodicalId":49518,"journal":{"name":"Simulation Modelling Practice and Theory","volume":"138 ","pages":"Article 103037"},"PeriodicalIF":3.5,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-15DOI: 10.1016/j.simpat.2024.103040
Qilin Chen , Deqiang He , Zhenzhen Jin , Ziyang Ren , Tiexiang Liu , Sheng Shan
Intrusion detection techniques play an important role in the security measures of train communication network (TCN). Due to the increasing openness of TCN, its security risk is also increasing, which makes TCN intrusion detection techniques receive more attention. Currently, there is an inherent class imbalance problem in the data samples for TCN intrusion detection. In addition, with the development of intrusion methods, intrusion traffic becomes more stealthy and the boundaries between intrusion traffic and normal traffic become increasingly ambiguous. Together, these issues contribute to the degradation of TCN intrusion detection performance. To address these challenges, A TCN intrusion detection method based on a multi-scale residual network with global and local attention mechanism (MSRNet-GLAM) is proposed. First, a multi-scale residual network is utilized to enhance the model's ability to extract different deep features of network traffic, thus better capturing the differences between categories. Then, the model is guided to focus on learning key information in global and local features by introducing the global and local attention mechanism (GLAM), which reduces the fitting of redundant information in the majority class samples and improves the model's generalization ability and sensitivity to the detection of the minority class samples. In addition, an improved focus loss function (IFL) is introduced to further improve the model's detection ability for minority class samples and stealthy intrusion samples with ambiguous class boundaries by increasing the loss weights of difficult-to-classify samples. A simulation network platform is built to simulate the scenario of TCN under intrusion, and data are collected for the training and validation of the intrusion detection model. Through testing on the simulation platform, the proposed method achieves 99.51 %, 98.98 %, 99.54 %, and 99.26 % in accuracy, precision, recall, and F1 score, respectively, which validates the effectiveness and superiority of the method in TCN intrusion detection.
{"title":"MSRNet-GLAM: A novel intrusion detection method for train communication network","authors":"Qilin Chen , Deqiang He , Zhenzhen Jin , Ziyang Ren , Tiexiang Liu , Sheng Shan","doi":"10.1016/j.simpat.2024.103040","DOIUrl":"10.1016/j.simpat.2024.103040","url":null,"abstract":"<div><div>Intrusion detection techniques play an important role in the security measures of train communication network (TCN). Due to the increasing openness of TCN, its security risk is also increasing, which makes TCN intrusion detection techniques receive more attention. Currently, there is an inherent class imbalance problem in the data samples for TCN intrusion detection. In addition, with the development of intrusion methods, intrusion traffic becomes more stealthy and the boundaries between intrusion traffic and normal traffic become increasingly ambiguous. Together, these issues contribute to the degradation of TCN intrusion detection performance. To address these challenges, A TCN intrusion detection method based on a multi-scale residual network with global and local attention mechanism (MSRNet-GLAM) is proposed. First, a multi-scale residual network is utilized to enhance the model's ability to extract different deep features of network traffic, thus better capturing the differences between categories. Then, the model is guided to focus on learning key information in global and local features by introducing the global and local attention mechanism (GLAM), which reduces the fitting of redundant information in the majority class samples and improves the model's generalization ability and sensitivity to the detection of the minority class samples. In addition, an improved focus loss function (IFL) is introduced to further improve the model's detection ability for minority class samples and stealthy intrusion samples with ambiguous class boundaries by increasing the loss weights of difficult-to-classify samples. A simulation network platform is built to simulate the scenario of TCN under intrusion, and data are collected for the training and validation of the intrusion detection model. Through testing on the simulation platform, the proposed method achieves 99.51 %, 98.98 %, 99.54 %, and 99.26 % in accuracy, precision, recall, and F1 score, respectively, which validates the effectiveness and superiority of the method in TCN intrusion detection.</div></div>","PeriodicalId":49518,"journal":{"name":"Simulation Modelling Practice and Theory","volume":"138 ","pages":"Article 103040"},"PeriodicalIF":3.5,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The emergence of vehicular edge computing (VEC) has introduced a new computational paradigm for high-quality processing of computing services in Internet of Vehicles (IoV) scenarios. However, due to the limited computational resources of the VEC server, it is not sufficient to adequately meet the demand for highly concurrent computational services in high-density vehicular communication networks. To address this issue, we consider an idle mobile vehicles assisted vehicular edge computing framework and propose a hybrid Stackelberg-Match cooperative task offloading and resource pricing algorithm (SMOP). The algorithm considers the mobility of vehicles and the duration of channels, coordinating the computational resources of fixed VEC servers and idle mobile vehicles within the vehicular network (VN). This enhances offloading efficiency and maximizes participant benefits. Specifically, the Stackelberg game is used to derive differentiated pricing schemes for idle mobile vehicles and VEC servers for different vehicular tasks, and the stable matching method is employed to determine task offloading strategies. Finally, we conduct experiments on a real Chengdu traffic dataset. The results demonstrate that the proposed solution effectively reduces offloading costs and exhibits strong robustness in handling latency-sensitive and data-intensive service requests.
{"title":"Incentive-driven computation offloading and resource pricing strategy in vehicular edge computing assisted with idle mobile vehicles","authors":"Shanchen Pang, Baoyun Chen, Xiao He, Nuanlai Wang, Zhi Lu, Shengzhe Zhao, Zixuan Fan, Yanxiang Zhang","doi":"10.1016/j.simpat.2024.103035","DOIUrl":"10.1016/j.simpat.2024.103035","url":null,"abstract":"<div><div>The emergence of vehicular edge computing (VEC) has introduced a new computational paradigm for high-quality processing of computing services in Internet of Vehicles (IoV) scenarios. However, due to the limited computational resources of the VEC server, it is not sufficient to adequately meet the demand for highly concurrent computational services in high-density vehicular communication networks. To address this issue, we consider an idle mobile vehicles assisted vehicular edge computing framework and propose a hybrid Stackelberg-Match cooperative task offloading and resource pricing algorithm (SMOP). The algorithm considers the mobility of vehicles and the duration of channels, coordinating the computational resources of fixed VEC servers and idle mobile vehicles within the vehicular network (VN). This enhances offloading efficiency and maximizes participant benefits. Specifically, the Stackelberg game is used to derive differentiated pricing schemes for idle mobile vehicles and VEC servers for different vehicular tasks, and the stable matching method is employed to determine task offloading strategies. Finally, we conduct experiments on a real Chengdu traffic dataset. The results demonstrate that the proposed solution effectively reduces offloading costs and exhibits strong robustness in handling latency-sensitive and data-intensive service requests.</div></div>","PeriodicalId":49518,"journal":{"name":"Simulation Modelling Practice and Theory","volume":"138 ","pages":"Article 103035"},"PeriodicalIF":3.5,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.simpat.2024.103039
Jingyao Wang , Kezhong Liu , Zhitao Yuan , Xing Yang , Xiaolie Wu
With the expansion of coastal ports, the number of super-large berths is on the rise. It has become imperative to accurately assess the operational impact of these berths, optimize berth utilization, and minimize ship delays. In this study, a detailed simulation model of super-large ship arrivals and departures was developed, focusing on the Ningbo-Zhoushan Port. The model accounts for various special navigation constraints, including berthing and departure time windows, safety separations, tidal constraints, and interference from neighboring berths. The simulation results highlight a significant disparity in waiting times between arriving and departing ships, with daytime restrictions and berth time windows emerging as the primary factors influencing wait times. Consequently, several improvement measures are proposed. These include implementing priority rules based on time windows, establishing additional inner anchorages, and reducing safety separations. Among these, reducing safety separations offers the best cost-effectiveness due to its low application cost and effective results. Although these measures may lead to varying waiting times among berths, they collectively contribute to a substantial 25.6% reduction in overall waiting time. This study offers valuable insights and practical guidance for the planning, construction, and operation of super-large berths in coastal ports.
{"title":"Simulation modeling of super-large ships traffic: Insights from Ningbo-Zhoushan Port for coastal port management","authors":"Jingyao Wang , Kezhong Liu , Zhitao Yuan , Xing Yang , Xiaolie Wu","doi":"10.1016/j.simpat.2024.103039","DOIUrl":"10.1016/j.simpat.2024.103039","url":null,"abstract":"<div><div>With the expansion of coastal ports, the number of super-large berths is on the rise. It has become imperative to accurately assess the operational impact of these berths, optimize berth utilization, and minimize ship delays. In this study, a detailed simulation model of super-large ship arrivals and departures was developed, focusing on the Ningbo-Zhoushan Port. The model accounts for various special navigation constraints, including berthing and departure time windows, safety separations, tidal constraints, and interference from neighboring berths. The simulation results highlight a significant disparity in waiting times between arriving and departing ships, with daytime restrictions and berth time windows emerging as the primary factors influencing wait times. Consequently, several improvement measures are proposed. These include implementing priority rules based on time windows, establishing additional inner anchorages, and reducing safety separations. Among these, reducing safety separations offers the best cost-effectiveness due to its low application cost and effective results. Although these measures may lead to varying waiting times among berths, they collectively contribute to a substantial 25.6% reduction in overall waiting time. This study offers valuable insights and practical guidance for the planning, construction, and operation of super-large berths in coastal ports.</div></div>","PeriodicalId":49518,"journal":{"name":"Simulation Modelling Practice and Theory","volume":"138 ","pages":"Article 103039"},"PeriodicalIF":3.5,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.simpat.2024.103038
Yazhen Sun , Longyan Wang , Jinchang Wang , Changgen Tan , Youlin Ye , Kun Lin
The Holmquist‒Johnson‒Cook (HJC) model is a commonly used constitutive model for simulations of the dynamic response and damage characteristics of geotechnical materials under explosions and impacts. However, certain deficiencies in its strength, strain rate, and damage models limit its computational effectiveness. Therefore, this paper first introduced the constitutive relation of the HJC. Then, the single-strength equation of the original HJC was improved by adopting three limiting surfaces and considering the impact of the Lode-angle on the yield surface. The hyperbolic tangent function was employed to model the rate effect, and the recommended strain rate parameters for rock materials were provided. Furthermore, an exponential strain softening function-based tensile damage equation was introduced to address tensile damage under negative pressure. On this basis, a method for determining parameters for the modified HJC in rock materials was proposed. Finally, the modified model was incorporated into the LS-DYNA material library using secondary development techniques, and multiple types of impact and explosion experiments on different types of rock materials were simulated using both the original and modified HJC. Additionally, the modified HJC was compared with several other modified HJC versions from various perspectives. It has been found that the simulation results of the modified HJC are in closer agreement with the experimental results than those of the original HJC. Compared to other modified HJC models, the modified HJC proposed in this paper offers a broader range of applications and a better compromise between computational efficiency and the number of parameters.
{"title":"A modified Holmquist‒Johnson‒Cook (HJC) constitutive model and its application to numerical simulations of explosions and impacts in rock materials","authors":"Yazhen Sun , Longyan Wang , Jinchang Wang , Changgen Tan , Youlin Ye , Kun Lin","doi":"10.1016/j.simpat.2024.103038","DOIUrl":"10.1016/j.simpat.2024.103038","url":null,"abstract":"<div><div>The Holmquist‒Johnson‒Cook (HJC) model is a commonly used constitutive model for simulations of the dynamic response and damage characteristics of geotechnical materials under explosions and impacts. However, certain deficiencies in its strength, strain rate, and damage models limit its computational effectiveness. Therefore, this paper first introduced the constitutive relation of the HJC. Then, the single-strength equation of the original HJC was improved by adopting three limiting surfaces and considering the impact of the Lode-angle on the yield surface. The hyperbolic tangent function was employed to model the rate effect, and the recommended strain rate parameters for rock materials were provided. Furthermore, an exponential strain softening function-based tensile damage equation was introduced to address tensile damage under negative pressure. On this basis, a method for determining parameters for the modified HJC in rock materials was proposed. Finally, the modified model was incorporated into the LS-DYNA material library using secondary development techniques, and multiple types of impact and explosion experiments on different types of rock materials were simulated using both the original and modified HJC. Additionally, the modified HJC was compared with several other modified HJC versions from various perspectives. It has been found that the simulation results of the modified HJC are in closer agreement with the experimental results than those of the original HJC. Compared to other modified HJC models, the modified HJC proposed in this paper offers a broader range of applications and a better compromise between computational efficiency and the number of parameters.</div></div>","PeriodicalId":49518,"journal":{"name":"Simulation Modelling Practice and Theory","volume":"138 ","pages":"Article 103038"},"PeriodicalIF":3.5,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-12DOI: 10.1016/j.simpat.2024.103030
Miguel Torres-Torriti, Matias Rojas-Sepulveda
Visual diagrammatic programming and block diagrams have been indispensable tools for systems modeling and simulation across research, development, and educational fields for several decades. Despite the availability of mature commercial and free software tools, there is a lack of information publicly accessible on algorithms for processing block diagrams that represent dynamical systems and simulate the corresponding models. A gap in the existing literature is the absence of mathematically formal and complete proposals of algorithms for processing block diagrams that are multigraphs containing directed cyclic graphs, and not just simpler directed graphs. The lack of a detailed exposition concerning the practical implementation of such algorithms is also a gap. This gap is likely because the simulation systems based on block diagram descriptions that have become de facto industry standards use proprietary solutions, even if their origins can be traced back to work done in research centers and universities more than seven decades ago. In response to these challenges, this paper summarizes the historical evolution of related paradigms, such as data flow diagrams, signal flow graphs, bond graphs, and block diagrams. We propose a general algorithm for block diagram processing and present an open-source software tool for Python that implements a diagrammatic visual programming interface and the proposed block diagram processing algorithm. The key contributions to the field of systems modeling and simulation can be summarized as follows. Firstly, the exposition of the algorithm formally proving its correctness, offers transparency which facilitates further research and development in the field, enabling academics and professionals to adapt, enhance, or expand upon the existing capabilities of the tool. Secondly, the implementation of a Python library and tool released as an open-source solution for simulating signal processing and dynamical systems through block diagrams by integrating the proposed algorithm capable of efficiently handling multigraph representations, including those with directed cyclic graphs. Ensuring accessibility of the tool to researchers, developers, and educators fosters innovation, research and empowers educators by providing them with a versatile tool that can be used to teach complex systems modeling and simulation concepts in a practical, hands-on manner across various domains, such as control systems, electrical engineering, and computer science.
{"title":"An algorithm for processing block diagram models of dynamical systems and an open-source visual-programming simulation tool","authors":"Miguel Torres-Torriti, Matias Rojas-Sepulveda","doi":"10.1016/j.simpat.2024.103030","DOIUrl":"10.1016/j.simpat.2024.103030","url":null,"abstract":"<div><div>Visual diagrammatic programming and block diagrams have been indispensable tools for systems modeling and simulation across research, development, and educational fields for several decades. Despite the availability of mature commercial and free software tools, there is a lack of information publicly accessible on algorithms for processing block diagrams that represent dynamical systems and simulate the corresponding models. A gap in the existing literature is the absence of mathematically formal and complete proposals of algorithms for processing block diagrams that are multigraphs containing directed cyclic graphs, and not just simpler directed graphs. The lack of a detailed exposition concerning the practical implementation of such algorithms is also a gap. This gap is likely because the simulation systems based on block diagram descriptions that have become <em>de facto</em> industry standards use proprietary solutions, even if their origins can be traced back to work done in research centers and universities more than seven decades ago. In response to these challenges, this paper summarizes the historical evolution of related paradigms, such as data flow diagrams, signal flow graphs, bond graphs, and block diagrams. We propose a general algorithm for block diagram processing and present an open-source software tool for Python that implements a diagrammatic visual programming interface and the proposed block diagram processing algorithm. The key contributions to the field of systems modeling and simulation can be summarized as follows. Firstly, the exposition of the algorithm formally proving its correctness, offers transparency which facilitates further research and development in the field, enabling academics and professionals to adapt, enhance, or expand upon the existing capabilities of the tool. Secondly, the implementation of a Python library and tool released as an open-source solution for simulating signal processing and dynamical systems through block diagrams by integrating the proposed algorithm capable of efficiently handling multigraph representations, including those with directed cyclic graphs. Ensuring accessibility of the tool to researchers, developers, and educators fosters innovation, research and empowers educators by providing them with a versatile tool that can be used to teach complex systems modeling and simulation concepts in a practical, hands-on manner across various domains, such as control systems, electrical engineering, and computer science.</div></div>","PeriodicalId":49518,"journal":{"name":"Simulation Modelling Practice and Theory","volume":"138 ","pages":"Article 103030"},"PeriodicalIF":3.5,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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