Performance Evaluation最新文献_第4页

Discrete Bayesian Optimization via Machine Learning 基于机器学习的离散贝叶斯优化

IF 1 4区计算机科学 Q4 COMPUTER SCIENCE, HARDWARE & ARCHITECTURE

Performance Evaluation

Pub Date : 2025-09-01 Epub Date: 2025-05-21 DOI: 10.1016/j.peva.2025.102487

Roberto Sala, Bruno Guindani, Danilo Ardagna, Alessandra Guglielmi

Bayesian Optimization (BO) is a family of powerful algorithms designed to solve complex optimization problems involving expensive black-box functions. These sequential algorithms iteratively update a surrogate model of the objective function (OF), effectively balancing exploration and exploitation to identify near-optimal solutions within a limited number of iterations. Originally designed for continuous, unconstrained domains, its efficiency has inspired adaptations for discrete, constrained optimization problems. On the other hand, Machine Learning (ML) models allow accurate predictions for black-box functions, although they typically require large amounts of data for training. Leveraging the strengths of BO and ML, research tackles the challenge of identifying optimal configurations in the context of cloud computing. This paradigm has become pervasive due to its ability to provide flexible and scalable resources. Identifying the optimal hardware-software configuration is essential for minimizing costs while meeting Quality of Service constraints. This task involves solving complex optimization problems over multidimensional discrete domains and black-box objective functions and constraints, within a limited number of iterations. To address this challenge, this work introduces d-MALIBOO, a BO-based algorithm that integrates ML techniques to enhance the efficiency of finding near-optimal solutions in discrete and bounded domains. While BO builds the surrogate model of the OF, ML models determine the feasible region of the black-box constraints and guide the BO algorithm toward promising regions of the discrete domain. Furthermore, we introduce an

ɛ

-greedy approach to favor exploration in domains with multiple local optima. Experimental results show that our algorithm outperforms OpenTuner, a popular framework for constrained optimization, by reducing the average regret by 29%, and SVM-CBO, a BO-based algorithm that integrates SVM models to determine the feasible region, by 82%.

贝叶斯优化（BO）是一组功能强大的算法，用于解决涉及昂贵的黑盒函数的复杂优化问题。这些顺序算法迭代地更新目标函数（of）的代理模型，有效地平衡探索和利用，以在有限的迭代次数内确定接近最优的解决方案。最初是为连续的、无约束的领域设计的，它的效率激发了对离散的、有约束的优化问题的适应。另一方面，机器学习（ML）模型允许对黑箱函数进行准确的预测，尽管它们通常需要大量的数据进行训练。利用BO和ML的优势，研究解决了在云计算环境中识别最佳配置的挑战。由于能够提供灵活和可扩展的资源，这种范式已经变得普遍。确定最佳的硬件软件配置对于在满足服务质量约束的同时最小化成本至关重要。该任务涉及在有限的迭代次数内解决多维离散域和黑盒目标函数和约束上的复杂优化问题。为了应对这一挑战，这项工作引入了d-MALIBOO，这是一种基于bo的算法，它集成了ML技术，以提高在离散和有界域中寻找近最优解的效率。BO构建of的代理模型，ML模型确定黑箱约束的可行区域，并引导BO算法走向离散域的有希望区域。此外，我们还引入了一种“贪婪”方法，以便在具有多个局部最优解的领域中进行勘探。实验结果表明，我们的算法比OpenTuner（一种流行的约束优化框架）的平均遗憾率降低了29%，比SVM- cbo（一种基于bo的集成SVM模型来确定可行区域的算法）的平均遗憾率降低了82%。

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引用次数: 0

Optimizing latency for caching with delayed hits in non-stationary environment 优化非固定环境中带有延迟命中的缓存的延迟

IF 1 4区计算机科学 Q4 COMPUTER SCIENCE, HARDWARE & ARCHITECTURE

Performance Evaluation

Pub Date : 2025-09-01 Epub Date: 2025-05-20 DOI: 10.1016/j.peva.2025.102488

Bowen Jiang, Yubo Yang, Bo Jiang

Caching plays a crucial role in many latency-sensitive systems, including content delivery networks, edge computing, and microprocessors. As the ratio between system throughput and transmission latency increases, delayed hits in cache problems become more prominent. In real-world scenarios, object access patterns often exhibit a non-stationary nature. In this paper, we investigate the latency optimization problem for caching with delayed hits in a non-stationary environment, where object sizes and fetching latencies are both non-uniform. We first find that given known future arrivals, evicting the object with the larger size, a higher aggregate delay due to miss and arriving the farthest in the future brings more gains in reducing latency. Following our findings, we design an online learning framework to make cache decisions more effectively. The first component of this framework utilizes historical data within the training window to estimate the object’s non-stationary arrival process, modeled as a mixture of log-gaussian distributions. Subsequently, we predict future arrivals based on this estimated distribution. According to these predicted future arrivals, we can determine the priority of eviction candidates using our defined rank function. Experimental results on four real-world traces show that our algorithm consistently reduces latency by

2 % - 10 %

on average compared to state-of-the-art algorithms.

缓存在许多对延迟敏感的系统中起着至关重要的作用，包括内容交付网络、边缘计算和微处理器。随着系统吞吐量与传输延迟之比的增大，缓存中的延迟命中问题变得更加突出。在实际场景中，对象访问模式通常表现出非固定的性质。在本文中，我们研究了在对象大小和获取延迟都不均匀的非固定环境下，具有延迟命中的缓存的延迟优化问题。我们首先发现，给定已知的未来到达，驱逐具有较大尺寸的对象，由于错过和到达最远的未来而导致的更高的总延迟可以在减少延迟方面获得更多收益。根据我们的发现，我们设计了一个在线学习框架来更有效地做出缓存决策。该框架的第一个组成部分利用训练窗口内的历史数据来估计目标的非平稳到达过程，建模为对数高斯分布的混合。随后，我们根据这一估计分布预测未来的到达人数。根据这些预测的未来到达，我们可以使用我们定义的排名函数确定驱逐候选人的优先级。在四个真实世界轨迹上的实验结果表明，与最先进的算法相比，我们的算法平均可以减少2% - 10%的延迟。

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引用次数: 0

Virtual caching with apportioned objects for mobile virtual reality 为移动虚拟现实分配对象的虚拟缓存

IF 1 4区计算机科学 Q4 COMPUTER SCIENCE, HARDWARE & ARCHITECTURE

Performance Evaluation

Pub Date : 2025-09-01 Epub Date: 2025-06-14 DOI: 10.1016/j.peva.2025.102500

Nader Alfares, George Kesidis

We consider a content-caching system for Virtual or Augmented Reality (VR/AR) that is shared by a number of user groups. The cache could be located in an edge–cloud datacenter and the users could be mobile. Each user group operates its own LRU-list of a certain capacity in the shared cache. The length of objects simultaneously appearing in plural LRU-lists is equally divided (apportioned) among them, i.e., object sharing among the LRUs. We provide a working-set approximation for this system to quickly estimate the cache-hit probabilities for objects apportioned across user groups. We also prove that a solution to the working-set approximation exists. A way to reduce ripple evictions is discussed and some numerical performance results are provided based on Zipf-distributed object popularities. To evaluate our apportioned object sharing system in a VR context, we introduce a benchmark specifically designed for VR streaming, addressing the latency and Quality of Experience (QoE) challenges that arise due to VR’s dynamic fields of view (FoVs) and user synchronization requirements. Using the VR benchmark, we present additional numerical results for cache-hit rates and users’ QoE to illustrate the system’s effectiveness under VR streaming conditions.

我们考虑了一个由多个用户组共享的虚拟或增强现实（VR/AR）的内容缓存系统。缓存可以位于边缘云数据中心，用户可以是移动的。每个用户组在共享缓存中操作自己的一定容量的lru列表。同时出现在多个lru -list中的对象长度在多个lru -list中平均分配，即lru之间的对象共享。我们为该系统提供了一个工作集近似值，以快速估计跨用户组分配的对象的缓存命中概率。我们还证明了工作集近似的一个解的存在。讨论了一种减少波纹驱逐的方法，并给出了基于zipf分布对象流行度的一些数值性能结果。为了在VR环境中评估我们的分配对象共享系统，我们引入了一个专门为VR流设计的基准，解决了由于VR的动态视场（fov）和用户同步要求而产生的延迟和体验质量（QoE）挑战。使用VR基准，我们给出了额外的缓存命中率和用户QoE的数值结果，以说明系统在VR流条件下的有效性。

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引用次数: 0

Inference for dynamic Erdős–Rényi random graphs under regime switching 状态切换下动态Erdős-Rényi随机图的推理

IF 1 4区计算机科学 Q4 COMPUTER SCIENCE, HARDWARE & ARCHITECTURE

Performance Evaluation

Pub Date : 2025-09-01 Epub Date: 2025-06-12 DOI: 10.1016/j.peva.2025.102499

Michel Mandjes , Jiesen Wang

This paper examines a model involving two dynamic Erdős–Rényi random graphs that evolve in parallel, with edges in each graph alternating between being present and absent according to specified on- and off-time distributions. A key feature of our setup is regime switching: the graph that is observed at any given moment depends on the state of an underlying background process, which is modeled as an alternating renewal process. This modeling framework captures a common situation in various real-world applications, where the observed network is influenced by a (typically unobservable) background process. Such scenarios arise, for example, in economics, communication networks, and biological systems.

In our setup we only have access to aggregate quantities such as the number of active edges or the counts of specific subgraphs (such as stars or complete graphs) in the observed graph; importantly, we do not observe the mode. The objective is to estimate the on- and off-time distributions of the edges in each of the two dynamic Erdős–Rényi random graphs, as well as the distribution of time spent in each of the two modes. By employing parametric models for the on- and off-times and the background process, we develop a method of moments approach to estimate the relevant parameters. Experimental evaluations are conducted to demonstrate the effectiveness of the proposed method in recovering these parameters.

本文研究了一个涉及两个并行演化的动态Erdős-Rényi随机图的模型，每个图中的边根据指定的开、关时间分布在存在和不存在之间交替。我们设置的一个关键特征是状态切换：在任何给定时刻观察到的图取决于底层背景进程的状态，该背景进程被建模为交替更新过程。此建模框架捕获了各种实际应用程序中的常见情况，其中观察到的网络受到（通常不可观察的）背景进程的影响。例如，在经济学、通信网络和生物系统中都会出现这种情况。在我们的设置中，我们只能访问聚合量，例如观察图中活动边的数量或特定子图（如星图或完全图）的计数；重要的是，我们没有观察到模式。目标是估计两个动态Erdős-Rényi随机图中每个边的开、关时间分布，以及在每个模式中花费的时间分布。通过采用开关时间和背景过程的参数模型，提出了一种矩量法估计相关参数的方法。实验验证了该方法在恢复这些参数方面的有效性。

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引用次数: 0

Optimal strategy against straightforward bidding in clock auctions 时钟拍卖中直接竞价的最优策略

IF 0.8 4区计算机科学 Q4 COMPUTER SCIENCE, HARDWARE & ARCHITECTURE

Performance Evaluation

Pub Date : 2025-09-01 Epub Date: 2025-07-23 DOI: 10.1016/j.peva.2025.102502

Jad Zeroual , Marianne Akian , Aurélien Bechler , Matthieu Chardy , Stéphane Gaubert

We study a model of auction representative of the 5G auction in France. We determine the optimal strategy of a bidder, assuming that the valuations of competitors are unknown to this bidder and that competitors adopt the straightforward bidding strategy. Our model is based on a Partially Observable Markov Decision Process (POMDP). This POMDP admits a concise statistics, avoiding the solution of a dynamic programming equation in the space of beliefs. In addition, under this optimal strategy, the expected gain of the bidder does not decrease if competitors deviate from straightforward bidding. We illustrate our results by numerical experiments, comparing the value of the bidder with the value of a perfectly informed one.

我们研究了一个以法国5G拍卖为代表的拍卖模型。我们确定了竞标者的最优策略，假设竞标者不知道竞争对手的估值，且竞争对手采用直接投标策略。我们的模型基于部分可观察马尔可夫决策过程（POMDP）。该POMDP允许简洁的统计，避免了在信念空间求解动态规划方程。此外，在该最优策略下，即使竞争对手偏离直接竞标，竞标者的期望收益也不会降低。我们通过数值实验来说明我们的结果，将出价者的价值与完全知情的价值进行比较。

引用次数: 0

Optimizing spatial modulation MIMO IoT systems with full-duplex/half-duplex UAVs and enhanced transmit antenna selection 优化空间调制MIMO物联网系统与全双工/半双工无人机和增强的发射天线选择

IF 1 4区计算机科学 Q4 COMPUTER SCIENCE, HARDWARE & ARCHITECTURE

Performance Evaluation

Pub Date : 2025-06-01 Epub Date: 2025-03-13 DOI: 10.1016/j.peva.2025.102481

Bao The Phung , Ba Cao Nguyen , Nguyen Van Vinh , Bui Vu Minh , Nguyen Huu Khanh Nhan

Multiple-input multiple-output (MIMO) systems play a crucial role in elevating the efficiency and reliability of communication networks, especially within Internet of Things (IoT) applications. This article introduces a novel approach involving full-duplex (FD) and half-duplex (HD) relays mounted on unmanned aerial vehicles (UAVs) to enhance MIMO systems. Incorporating spatial modulation (SM) and transmit antenna selection (TAS) techniques aims to optimize system performance while reducing computational complexity to meet IoT requirements. The article mathematically formulates outage probabilities (OPs) and system throughputs (STs) for the proposed MIMO-IoT-UAV systems utilizing SM with FD/HD-UAV, both with and without TAS, over practical Nakagami-

m

channels. Numerical illustrations underscore the advantages of employing FD/HD-UAV and TAS in MIMO-IoT-UAV systems. Specifically, OPs with TAS are significantly lower, while STs with TAS are notably higher than their counterparts without TAS. Additionally, TAS with FD-UAV yields greater benefits than HD-UAV, particularly in preventing the error floor associated with residual self-interference (RSI). To mitigate this error floor in MIMO-IoT-UAV systems using FD-UAV, an effective strategy involves increasing the number of transmit/receive antennas. The choice between FD and HD modes hinges on parameters such as transmit power, data rate, and RSI. Depending on these factors, FD-UAV performance may exhibit lower or higher error rates than HD-UAV. Hence, the optimal selection of FD or HD mode, combined with TAS, is essential for enhancing MIMO-IoT-UAV system performance. This optimization process should consider parameters like RSI level, the number of transmit/receive antennas, data rate requirements, and UAV position to ensure efficient and reliable communication across diverse scenarios.

多输入多输出（MIMO）系统在提高通信网络的效率和可靠性方面发挥着至关重要的作用，特别是在物联网（IoT）应用中。本文介绍了一种安装在无人机上的全双工（FD）和半双工（HD）继电器来增强MIMO系统的新方法。结合空间调制（SM）和发射天线选择（TAS）技术旨在优化系统性能，同时降低计算复杂性，以满足物联网要求。本文在数学上计算了在实际的Nakagami-m通道上使用SM和FD/HD-UAV的拟议MIMO-IoT-UAV系统的中断概率（OPs）和系统吞吐量（STs），包括有和没有TAS。数值实例强调了在MIMO-IoT-UAV系统中采用FD/HD-UAV和TAS的优势。具体而言，有TAS的OPs显著低于无TAS的OPs，而有TAS的STs显著高于无TAS的STs。此外，配备FD-UAV的TAS比HD-UAV具有更大的优势，特别是在防止与残余自干扰（RSI）相关的误差方面。为了在使用FD-UAV的MIMO-IoT-UAV系统中减轻这种误差层，一种有效的策略包括增加发射/接收天线的数量。FD和HD模式之间的选择取决于传输功率、数据速率和RSI等参数。取决于这些因素，FD-UAV的性能可能比HD-UAV表现出更低或更高的错误率。因此，优化选择FD或HD模式，并结合TAS，对于提高MIMO-IoT-UAV系统性能至关重要。该优化过程应考虑RSI水平、发射/接收天线数量、数据速率要求和无人机位置等参数，以确保在不同场景下高效可靠的通信。

{"title":"Optimizing spatial modulation MIMO IoT systems with full-duplex/half-duplex UAVs and enhanced transmit antenna selection","authors":"Bao The Phung , Ba Cao Nguyen , Nguyen Van Vinh , Bui Vu Minh , Nguyen Huu Khanh Nhan","doi":"10.1016/j.peva.2025.102481","DOIUrl":"10.1016/j.peva.2025.102481","url":null,"abstract":"<div><div>Multiple-input multiple-output (MIMO) systems play a crucial role in elevating the efficiency and reliability of communication networks, especially within Internet of Things (IoT) applications. This article introduces a novel approach involving full-duplex (FD) and half-duplex (HD) relays mounted on unmanned aerial vehicles (UAVs) to enhance MIMO systems. Incorporating spatial modulation (SM) and transmit antenna selection (TAS) techniques aims to optimize system performance while reducing computational complexity to meet IoT requirements. The article mathematically formulates outage probabilities (OPs) and system throughputs (STs) for the proposed MIMO-IoT-UAV systems utilizing SM with FD/HD-UAV, both with and without TAS, over practical Nakagami-<span><math><mi>m</mi></math></span> channels. Numerical illustrations underscore the advantages of employing FD/HD-UAV and TAS in MIMO-IoT-UAV systems. Specifically, OPs with TAS are significantly lower, while STs with TAS are notably higher than their counterparts without TAS. Additionally, TAS with FD-UAV yields greater benefits than HD-UAV, particularly in preventing the error floor associated with residual self-interference (RSI). To mitigate this error floor in MIMO-IoT-UAV systems using FD-UAV, an effective strategy involves increasing the number of transmit/receive antennas. The choice between FD and HD modes hinges on parameters such as transmit power, data rate, and RSI. Depending on these factors, FD-UAV performance may exhibit lower or higher error rates than HD-UAV. Hence, the optimal selection of FD or HD mode, combined with TAS, is essential for enhancing MIMO-IoT-UAV system performance. This optimization process should consider parameters like RSI level, the number of transmit/receive antennas, data rate requirements, and UAV position to ensure efficient and reliable communication across diverse scenarios.</div></div>","PeriodicalId":19964,"journal":{"name":"Performance Evaluation","volume":"168 ","pages":"Article 102481"},"PeriodicalIF":1.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Energy-performance tradeoffs in server farms with batch services and setup times 具有批处理服务和设置时间的服务器群中的能源性能权衡

IF 1 4区计算机科学 Q4 COMPUTER SCIENCE, HARDWARE & ARCHITECTURE

Performance Evaluation

Pub Date : 2025-06-01 Epub Date: 2025-01-30 DOI: 10.1016/j.peva.2025.102468

Thu Le-Anh , Tuan Phung-Duc

Data centers consume a large amount of energy, much of which is wasted due to idle servers. Turning off idle servers might be an effective power-saving solution; however, there is a trade-off between energy savings and system performance. Hence, we propose a setup queueing model with a batching policy that allows servers to process a set of jobs simultaneously to minimize power consumption while maintaining acceptable performance. We consider an M/M/

c /

SET–BATCH queue, a multi-server batch service queue with a fixed batch size and setup times, and some variants, including systems in which idle servers delay before turning off or systems in which the batch size is dynamic. We analyze the steady-state probabilities and system performance of the M/M/

c /

SET–BATCH system and its variants. Our analysis of the M/M/

c /

SET–BATCH system with lower computational complexity is made possible by utilizing the special structure of the model. In addition, we use simulations to compare the M/M/

c /

SET–BATCH model with some other variants with different setup time distributions. The results suggest that the model performs better when the setup time has a larger coefficient of variation. Our results indicate that the batching policy enhances the system performance, especially when we allow servers to be idle before turning them off.

数据中心消耗大量的能源，其中很大一部分是由于服务器闲置而浪费的。关闭空闲服务器可能是一种有效的节能解决方案；然而，在节能和系统性能之间存在权衡。因此，我们提出了一个带有批处理策略的设置队列模型，该模型允许服务器同时处理一组作业，以最小化功耗，同时保持可接受的性能。我们考虑M/M/c/ SET-BATCH队列，一个具有固定批处理大小和设置时间的多服务器批处理服务队列，以及一些变体，包括空闲服务器在关闭之前延迟的系统或批处理大小是动态的系统。我们分析了M/M/c/ SET-BATCH系统及其变体的稳态概率和系统性能。利用模型的特殊结构，我们可以对计算复杂度较低的M/M/c/ SET-BATCH系统进行分析。此外，我们使用模拟来比较M/M/c/ SET-BATCH模型与其他一些具有不同设置时间分布的变体。结果表明，当设置时间的变异系数较大时，模型的性能较好。我们的结果表明，批处理策略提高了系统性能，特别是当我们允许服务器在关闭它们之前处于空闲状态时。

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引用次数: 0

Certificates and witnesses for multi-objective queries in Markov decision processes 马尔可夫决策过程中多目标查询的证书和见证

IF 1 4区计算机科学 Q4 COMPUTER SCIENCE, HARDWARE & ARCHITECTURE

Performance Evaluation

Pub Date : 2025-06-01 Epub Date: 2025-03-24 DOI: 10.1016/j.peva.2025.102482

Christel Baier, Calvin Chau, Sascha Klüppelholz

Probabilistic model checking is a technique for formally verifying the correctness of probabilistic systems w.r.t. given specifications. Typically, a model checking procedure outputs whether a specification is satisfied or not, but does not provide additional insights on the correctness of the result, thereby diminishing the trustworthiness and understandability of the verification process. In this work, we consider certifying verification algorithms that also provide an independently checkable certificate and witness in addition to the verification result. The certificate can be used to easily validate the correctness of the result and the witness provides useful diagnostic information, e.g. for debugging purposes. More specifically, we study certificates and witnesses for specifications in the form of multi-objective queries in Markov decision processes. We first consider multi-objective reachability and invariant queries and then extend our techniques to mean-payoff expectation and mean-payoff percentile queries. Thereby, we generalize previous works on certificates and witnesses for single reachability and invariant constraints. In essence, we derive certifying verification algorithms from known linear programming techniques and show that witnesses, both in the form of schedulers and subsystems, can be obtained from the certificates. As a proof-of-concept, we report on an implementation of our certifying verification algorithms and present experimental results, demonstrating the applicability on moderately-sized case studies.

概率模型检查是一种在给定规范下正式验证概率系统正确性的技术。通常，模型检查过程输出规范是否满足，但不提供对结果正确性的额外见解，从而降低了验证过程的可信度和可理解性。在这项工作中，我们考虑认证验证算法，除了验证结果之外，还提供独立可检查的证书和证人。证书可以用来很容易地验证结果的正确性，而见证提供了有用的诊断信息，例如用于调试目的。更具体地说，我们研究了马尔可夫决策过程中多目标查询形式的规范证书和见证。我们首先考虑多目标可达性和不变查询，然后将我们的技术扩展到平均收益期望和平均收益百分位查询。因此，我们推广了以往关于单可达性和不变约束的证书和见证的工作。从本质上讲，我们从已知的线性规划技术中推导出认证验证算法，并表明可以从证书中获得证人，无论是调度程序还是子系统。作为概念验证，我们报告了我们的认证验证算法的实现并提出了实验结果，证明了在中等规模的案例研究中的适用性。

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引用次数: 0

Controller synthesis in timed Büchi automata: Robustness and punctual guards 定时<s:1> chi自动机的控制器综合：鲁棒性和准时保护

IF 1 4区计算机科学 Q4 COMPUTER SCIENCE, HARDWARE & ARCHITECTURE

Performance Evaluation

Pub Date : 2025-06-01 Epub Date: 2025-04-05 DOI: 10.1016/j.peva.2025.102483

Benoît Barbot , Damien Busatto-Gaston , Catalin Dima , Youssouf Oualhadj

We consider the synthesis problem on timed automata with Büchi objectives, where delay choices made by a controller are subjected to small perturbations. Usually, the controller needs to avoid punctual guards, such as testing the equality of a clock to a constant. In this work, we generalize to a robustness setting that allows for punctual transitions in the automaton to be taken by controller with no perturbation. In order to characterize cycles that resist perturbations in our setting, we introduce a new structural requirement on the reachability relation along an accepting cycle of the automaton. This property is formulated on the region abstraction, and generalizes the existing characterization of winning cycles in the absence of punctual guards. We show that the problem remains within

PSPACE

despite the presence of punctual guards.

考虑具有 chi目标的时间自动机的综合问题，其中控制器所作的延迟选择受到小扰动的影响。通常，控制器需要避免守时保护，例如测试时钟与常数的相等性。在这项工作中，我们推广到一个鲁棒设置，该设置允许控制器在没有扰动的情况下采取自动机中的准时过渡。为了描述在我们的设置中抵抗扰动的周期，我们引入了一个新的结构要求，即自动机在一个接受周期上的可达关系。这一性质在区域抽象的基础上得到了表述，并推广了在没有准时守卫时获胜循环的现有特征。我们表明，尽管有准时的警卫，问题仍然存在于PSPACE。

引用次数: 0

A generalized result for the discrete-time two-queue randomly alternating service system 离散时间双队列随机交变服务系统的一个推广结果

IF 1 4区计算机科学 Q4 COMPUTER SCIENCE, HARDWARE & ARCHITECTURE

Performance Evaluation

Pub Date : 2025-06-01 Epub Date: 2025-04-03 DOI: 10.1016/j.peva.2025.102484

Herwig Bruneel, Arnaud Devos, Joris Walraevens

In this paper, we revisit the discrete-time two-queue randomly alternating service system, where one common server is shared by two queues by allocating the server, independently from slot to slot, with fixed probabilities to either queue. Arrivals of new customers into the two-queue system occur independently from slot to slot, but may be mutually dependent within a slot. They are characterized by the joint probability generating function (pgf)

A (z_{1}, z_{2})

of the numbers of arrivals in both queues during one time slot. The service times of all customers are equal to exactly one time slot.

We extend various existing results with respect to the queueing behavior of this system. Specifically, we show that the exact solutions that were previously found for the steady-state joint pgf

U (z_{1}, z_{2})

of the system contents in both queues for the scenarios of independent Bernoulli arrivals, identical Bernoulli arrivals, global geometric arrivals, global geometric group arrivals, and the superposition of identical Bernoulli arrivals and global geometric (group) arrivals, are all special cases of a more general result, which is valid for a whole class of arrival pgfs

A (z_{1}, z_{2})

that (among others) encompasses the aforementioned specific arrival scenarios. However, the defined class is much broader than this, and our new result allows the solution for entirely new arrival pgfs as well. We illustrate this abundantly with a large number of detailed examples. The proof of the general result is a mainly algebraic one and, unlike earlier studies, does not require intricate techniques from complex-function analysis.

本文重新研究了离散时间双队列随机交替服务系统，其中一个公共服务器由两个队列共享，独立于插槽分配服务器，每个队列具有固定的概率。进入双队列系统的新客户在每个时段独立出现，但在一个时段内可能相互依赖。它们的特征是一个时隙内两个队列到达人数的联合概率生成函数（pgf） A（z1,z2）。所有客户的服务时间正好等于一个时隙。我们扩展了关于该系统的排队行为的各种现有结果。具体来说，我们证明了在独立伯努利到达、相同伯努利到达、全局几何到达、全局几何群到达以及相同伯努利到达和全局几何（群）到达叠加的情况下，两个队列中系统内容的稳态联合pgf U（z1,z2）的精确解都是一个更一般结果的特殊情况。它适用于包含前面提到的特定到达场景的整个到达pgfs a （z1,z2）类。但是，所定义的类要比这广泛得多，并且我们的新结果也允许全新到达pgfs的解决方案。我们用大量详细的例子来充分说明这一点。一般结果的证明主要是代数证明，与早期的研究不同，它不需要复杂的复函数分析技术。

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引用次数: 0