Computers & Industrial Engineering最新文献_第7页

Toward energy-efficient blockchain system: A game theoretic analysis

IF 6.7 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers & Industrial Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.cie.2024.110821

Xu Wang , Ling-Yun Wu

The waste of energy is one of the major disadvantages when applying the permissionless blockchain technology such as the proof-of-work (PoW) consensus mechanism. In order to improve the energy efficiency, some new public blockchain systems without mining have been developed. In the blockchain with mining, the block creation rate is automatically adjusted by the system via the difficulty of the hash puzzle. In the blockchain without mining, the participating node can actively adjust its block creation rate instead of passively complying with the rule of system. In this new circumstance, how to maintain a desired block creation rate of the whole system through a proper mechanism design is an important task in the development of energy-efficient blockchain systems. In this study, we have established a two-party game model for the blockchain system without mining. Game participants (participating nodes) can obtain revenue by charging commission from the transactions recorded in the blocks, and at the same time, they need to bear block-building cost. Each node can adjust its own obtained income by controlling its block creation frequency. We considered the game in two situations based on the time delay of the same transaction arriving at two nodes. In the case without time delay, we gave a closed-form solution of Nash equilibrium, in which the block creation interval is proportional to the block-building cost, and inversely proportional to the transaction fee and to the revenue allocation proportion. In the case with time delay, we gave the theoretical analysis and the numerical solution of Nash equilibrium, and found that the conclusion is the same as the case without time delay. In a word, in the blockchain system without mining, the block-building cost and transaction fee can be utilized to control the block creation rate of the whole system, which makes the system remain steady even without mining. More important, how the transaction fees are allocated among the nodes will affect the final equilibrium. Therefore, in order to have positive incentives for participating nodes, it is necessary to reasonably design the allocation mechanism of transaction fees. This study provides theoretical support for the development of energy-efficient blockchain technology and brings about the hope to the future development of blockchain technology without mining.

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引用次数: 0

Accelerating the stabilized column generation using machine learning

IF 6.7 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers & Industrial Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.cie.2024.110837

Puja Sarkar , Vivekanand B. Khanapuri , Manoj Kumar Tiwari

Column Generation (CG) is a well-established methodology for tackling large-scale real-world optimization problems. Nevertheless, as problem sizes increase, challenges like long-tail effects and degeneracy become more prevalent. Various strategies for stabilizing dual variables have demonstrated their effectiveness in mitigating these challenges. Generally, numerical tests are employed to identify the best parameter values for stabilized CG using different configurations for the same problem. This study introduces an innovative approach using machine learning (ML) to predict the best algorithm configuration, eliminating the need for extensive numerical experimentation. The core objective of this study is to predict optimal dual variables to generate improved bounds in the Restricted Master Problem of stabilized CG. By and large, this comprehensive approach represents a robust and flexible framework, optimizing algorithm configurations and expediting the convergence of the CG model. Extensive computational experiments confirm the efficacy of our ML-based approach in accurately predicting optimal dual variables and outperforming conventional methods. The practical utility is exemplified in optimizing workforce scheduling, demonstrating significant reductions in computational time across problem instances. This real-world application highlights the remarkable benefits of the smart approach in enhancing the efficiency and effectiveness of CG-based optimization solutions.

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引用次数: 0

A robust multi-objective optimization model for grid-scale design of sustainable cropping patterns: A case study 用于网格尺度可持续种植模式设计的稳健多目标优化模型：案例研究

IF 6.7 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers & Industrial Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.cie.2024.110772

Nima Taheri , Mir Saman Pishvaee , Hamed Jahani

In the face of growing population, water scarcity, and increasing food demand, there is a pressing need to shift towards optimized, resource-efficient, climate-resilient, and sustainable agricultural practices. In light of that, designing a sustainable cropping pattern that considers the procedure of resource allocation based on land capabilities and crop features is vital for ensuring long-term food production and safeguarding the delicate balance of ecosystems. Motivated by this imperative, this study proposes a comprehensive framework that integrates Geographic Information System (GIS), System Dynamics (SD), and optimization to address the sustainable design of cropping patterns. The framework assesses grid-scale land suitability, models dynamic water resource interactions, and optimizes resource allocation based on crop calendar considerations. For the first time, a dynamic crop inventory is integrated into the cropping pattern optimization process, addressing food security concerns in a comprehensive manner. In order to evaluate the effect of uncertainties on the designed system, a robust optimization model is developed based on convex sets. The results demonstrate the advantages of the robust model in situations with uncertainty. Despite a 5% reduction in profit compared to the deterministic solution, the robust design achieves a 25% decrease in irrigation, highlighting the cost of ensuring sustainability. The deterministic approach prioritizes crops based on their economic value, whereas the robust solution considers the volume of irrigation required for a sustainable design. The managerial implications emphasize the importance of prioritizing water-efficient and climate-resilient agricultural practices to guarantee long-term food security.

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引用次数: 0

An exact approach for the two-dimensional strip packing problem with defects 有缺陷的二维带状堆积问题的精确方法

IF 6.7 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers & Industrial Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.cie.2025.110866

Shaowen Yao, Hao Zhang, Lijun Wei, Qiang Liu

The paper studies the two-dimensional strip packing problem with defects (2DSPP_D), focusing on packing rectangular items orthogonally within a fixed-width, variable-height strip that includes defects. The objective is to minimize the height of the strips used. This problem is important because it appears in many real-world applications, such as cutting processes for materials like paper or steel coils, where the goal is to minimize waste, and in continuous berth allocation problems, where the objective is to minimize total unloading time. Although this problem has a wide range of practical applications, it is rarely discussed in the literature. In this paper, we present an integer programming formulation and an exact two-stage approach. In the first stage of the exact method, the 2DSPP_D is converted into a two-dimensional orthogonal placement problem (2DOPP) by fixing the strip height. In the second stage, we solve this placement problem using a Benders’ decomposition method. If the 2DOPP proves infeasible, we increase the strip height and repeat the algorithm. We employ customized preprocessing techniques, lower bounding methods, and valid inequalities to enhance the two-stage approach. Additionally, we propose a skyline-based adaptive iterative search heuristic algorithm that provides tight upper bounds for the 2DSPP_D, incorporating a randomized local search strategy and an adaptive search strategy to enhance algorithm effectiveness. Extensive computational results show that our approach proves optimal solutions for small and medium-sized benchmark instances within a reasonable time and achieves close gap values between upper and lower bounds for large benchmark instances.

本文研究的是有缺陷的二维条状包装问题（2DSPP_D），重点是将矩形物品正交地包装在包括缺陷在内的固定宽度、可变高度的条状内。目标是尽量减少所用条带的高度。这个问题非常重要，因为它出现在许多实际应用中，例如纸张或钢卷等材料的切割过程，其目标是最大限度地减少浪费；以及连续泊位分配问题，其目标是最大限度地减少总卸载时间。虽然这个问题有广泛的实际应用，但文献中却很少讨论。在本文中，我们提出了一种整数编程公式和一种两阶段精确方法。在精确法的第一阶段，通过固定带钢高度，将 2DSPP_D 转换为二维正交放置问题 (2DOPP)。在第二阶段，我们使用本德斯分解法解决这个放置问题。如果 2DOPP 证明不可行，我们就增加带钢高度并重复该算法。我们采用定制的预处理技术、下限方法和有效不等式来改进两阶段方法。此外，我们还提出了一种基于天际线的自适应迭代搜索启发式算法，为 2DSPP_D 提供了严格的上界，并结合了随机局部搜索策略和自适应搜索策略，以提高算法的有效性。广泛的计算结果表明，我们的方法在合理的时间内证明了中小型基准实例的最优解，并在大型基准实例的上下限之间实现了接近的差距值。

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引用次数: 0

Personalized follow-up strategies with learning effects for disease monitoring

IF 6.7 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers & Industrial Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.cie.2024.110820

Mei Li , Zixian Liu , Xiaopeng Li , Guozheng Song

Effective follow-up strategies are crucial for managing patients’ risks of adverse outcomes (AOs) and associated costs. Current literature on follow-up strategy design primarily focuses on healthcare providers’ perspectives, often overlooking the significant role of patient learning behaviors in enhancing follow-up effectiveness during their healthcare journey. This paper investigates the impacts of two types of learning behaviors on follow-up strategy design. By employing the ‘virtual age’ and ‘learning parameters’, we assess the impact of follow-up services and learning behaviors on AO risks. A unified optimization model, based on patient heterogeneity, is then constructed to analyze the trade-off between follow-up services, AO risks, and the impact of patient learning behaviors. Formulated as a mixed integer nonlinear programming problem, the model is solved to determine the optimal frequency and timing of follow-up services over a planned horizon for heterogeneous patient groups. A case study focusing on pediatric type 1 diabetes mellitus patients demonstrates that learning behaviors can effectively control medical service costs while enhancing disease monitoring efficacy.

有效的随访策略对于控制患者的不良后果（AOs）风险和相关费用至关重要。目前有关随访策略设计的文献主要侧重于医疗服务提供者的视角，而往往忽视了患者的学习行为对提高医疗过程中随访效果的重要作用。本文研究了两种学习行为对随访策略设计的影响。通过使用 "虚拟年龄 "和 "学习参数"，我们评估了随访服务和学习行为对 AO 风险的影响。然后构建了一个基于患者异质性的统一优化模型，以分析随访服务、AO 风险和患者学习行为的影响之间的权衡。该模型被表述为一个混合整数非线性编程问题，通过求解该问题，可确定异质性患者群体在计划范围内随访服务的最佳频率和时间。以儿科 1 型糖尿病患者为重点的案例研究表明，学习行为可以有效控制医疗服务成本，同时提高疾病监测效果。

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引用次数: 0

Unleashing digital engineering for high-configurational systems: A taxonomy for developing digital engineering platforms 为高配置系统开发数字工程：开发数字工程平台的分类标准

IF 6.7 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers & Industrial Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.cie.2024.110814

Tobias Eberhardt , Dimitri Petrik , Walter Schaaf , Alexander Verl

The significance of digital servitization in the industrial engineering domain is becoming increasingly apparent. A significant number of component and system manufacturers are attempting to incorporate digital services and products into their existing product portfolios with the aim of enhancing customer value. A promising avenue for exploration is the combination of digital engineering approaches with digital platforms, which could result in creating a digital engineering platform. However, the solution space for designing digital engineering platforms is wide, increasing the complexity for industrial organizations to choose the right configuration. To cope with this complexity in the conception phase, this paper presents a configurable model in the form of a taxonomy for such a platform, developed on the basis of a systematic literature review and demonstrated by applying it in a case study with a component and system manufacturer in the field of vacuum handling technology. The taxonomy aims to systematize the different design options for digital engineering platforms and simplify the selection of an adequate platform configuration. The results further help advance the understanding of digital platform configurations to support the digital engineering of highly configurable systems and their servitization.

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引用次数: 0

Exact algorithms in bar nesting: How to cut general items from linear stocks so that wastage is minimised 条形排版的精确算法：如何从线性库存中切割一般物品，从而将损耗降至最低

IF 6.7 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers & Industrial Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.cie.2024.110838

Rhyd Lewis , Louis Bonnet

This paper proposes exact, polynomial-time algorithms that solve the problem of cutting items with angled sides from a single linear stock so that wastage is minimised. In industry, this problem is called “bar nesting”. Here we give an algorithmic framework that solves several important variants of the problem, including cutting items from stocks with asymmetric cross-sections, cutting items whose sides occur on different planes, and the minimum score separation problem.

引用次数: 0

Human–robot vs. human–manual teams: Understanding the dynamics of experience and performance variability in picker-to-parts order picking

IF 6.7 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers & Industrial Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.cie.2024.110750

Jonas Koreis

Recent technological advances have enabled firms to automate an increasing number of intralogistics operations, yet manual material handling remains pivotal in several industries, particularly in retail applications where brick-and-mortar warehouses still rely on manual picker-to-parts systems. These systems, while labor-intensive, are increasingly being supplemented by technologies such as automated guided vehicles (AGVs) to enhance performance and reduce physical strain on workers. The present study analyzed a pilot test of a new industrial truck deployed as an AGV that automatically follows order pickers in their travels within the warehouse of a brick-and-mortar grocery retailer. The data set comprises 342,601 pick location visits performed in one dedicated warehouse from 01 November 2022 to 30 June 2023, with three order pickers working with an AGV in a human–robot setting and five order pickers working with a manual industrial truck in a human–manual setting, with both groups sharing the identical aisle work space. The human–robot teams demonstrated a 3.6% reduction in order picking time compared to the human–manual teams, with a significant initial performance boost that plateaued over time. Experience had different impacts on the two groups: in the human–robot teams, the benefits of experience diminished more rapidly, indicating a lower incremental gain from additional experience compared to human–manual teams. Conversely, human–manual teams showed continuous improvement in performance as experience accumulated, with each additional day of experience leading to significant gains in order picking performance. The study also highlighted the variation in performance increase in human–robot teams, suggesting that while AGVs may enhance performance, the potential for inconsistent operational methods among workers can lead to fluctuating performance outcomes. The findings provide guidance for researchers and managers in understanding the impacts of experience and automation on performance, thereby aiding in the development of targeted training programs and operational strategies to maximize the benefits of AGVs.

最近的技术进步使企业能够将越来越多的内部物流操作自动化，但人工物料搬运在一些行业中仍然举足轻重，特别是在零售应用领域，实体仓库仍然依赖人工拣选机到零件系统。这些系统虽然是劳动密集型的，但越来越多地采用自动导引车（AGV）等技术作为补充，以提高性能并减轻工人的体力负担。本研究分析了一种新型工业卡车的试点测试，该卡车作为 AGV 部署，可自动跟随订单拣选人员在一家实体杂货零售商的仓库内移动。数据集包括 2022 年 11 月 1 日至 2023 年 6 月 30 日期间在一个专用仓库内执行的 342,601 次拣选位置访问，其中 3 名订单拣选员在人类-机器人环境下使用 AGV，5 名订单拣选员在人类-人工环境下使用手动工业卡车，两组人员共享相同的过道工作空间。与人工-机器人小组相比，人工-机器人小组的订单拣选时间缩短了 3.6%，最初的性能提升显著，但随着时间的推移逐渐趋于稳定。经验对两组的影响不同：在人类机器人团队中，经验带来的好处减少得更快，这表明与人类手动团队相比，更多经验带来的增益较低。相反，随着经验的积累，人类-机器人团队的绩效不断提高，每增加一天经验，订单拣选绩效就会显著提高。研究还强调了人类-机器人团队在提高绩效方面的差异，表明虽然 AGV 可以提高绩效，但工人之间操作方法的不一致可能导致绩效结果的波动。研究结果为研究人员和管理人员了解经验和自动化对绩效的影响提供了指导，从而有助于制定有针对性的培训计划和运营策略，最大限度地发挥 AGV 的效益。

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引用次数: 0

Data-driven multi-location inventory placement in digital commerce 数字商务中数据驱动的多地点库存布局

IF 6.7 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers & Industrial Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.cie.2024.110842

Yihua Wang , Stefan Minner

Digital commerce has become an indispensable part of global retail. Digital commerce retailers usually build large logistics networks with multiple distribution centers (DCs) to serve widespread consumers. In this paper, we study multi-location inventory placement for online retailers to fulfill customer demands. Specifically, we consider three decision-making problems: (i) in which DCs to place inventory, (ii) how to set base-stock levels for inventory-holding DCs, and (iii) from which DCs to fulfill customer demand. The main challenge is to achieve the optimal trade-off between inventory cost savings from inventory pooling and the increased demand fulfillment cost associated with placing inventory far from consumers. To investigate the trade-off, we propose a data-driven stochastic program under two different demand fulfillment policies, namely fixed and virtual pooling. We evaluate the effectiveness of the proposed method through a case study based on a real-world data set by a logistics company. The proposed method achieves an average cost reduction of 19.2% compared to the company’s current inventory placement policy. Further, we conduct ABC-XYZ analysis for more than 7,700 stock keeping units (SKUs) in the data set. The comparison of inventory placement decisions between different SKU categories suggests that digital commerce retailers should place more inventory in local DCs for SKUs with steadily high demand rates and pool more inventory at central DCs for SKUs with low demand rates and high variance. Additionally, we perform a systematic sensitivity analysis with controllable problem parameter configurations to investigate the impact of different parameters on inventory placement decisions.

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引用次数: 0

A comparison of reinforcement learning policies for dynamic vehicle routing problems with stochastic customer requests

IF 6.7 1区工程技术 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computers & Industrial Engineering

Pub Date : 2025-02-01 DOI: 10.1016/j.cie.2024.110747

Fabian Akkerman , Martijn Mes , Willem van Jaarsveld

This paper presents directions for using reinforcement learning with neural networks for dynamic vehicle routing problems (DVRPs). DVRPs involve sequential decision-making under uncertainty where the expected future consequences are ideally included in current decision-making. A frequently used framework for these problems is approximate dynamic programming (ADP) or reinforcement learning (RL), often in conjunction with a parametric value function approximation (VFA). A straightforward way to use VFA in DVRP is linear regression (LVFA), but more complex, non-linear predictors, e.g., neural network VFAs (NNVFA), are also widely used. Alternatively, we may represent the policy directly, using a linear policy function approximation (LPFA) or neural network PFA (NNPFA). The abundance of policies and design choices complicate the use of neural networks for DVRPs in research and practice. We provide a structured overview of the similarities and differences between the policy classes. Furthermore, we present an empirical comparison of LVFA, LPFA, NNVFA, and NNPFA policies. The comparison is conducted on several problem variants of the DVRP with stochastic customer requests. To validate our findings, we study realistic extensions of the stylized problem on (i) a same-day parcel pickup and delivery case in the city of Amsterdam, the Netherlands, and (ii) the routing of robots in an automated storage and retrieval system (AS/RS). Based on our empirical evaluation, we provide insights into the advantages and disadvantages of neural network policies compared to linear policies, and value-based approaches compared to policy-based approaches.

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引用次数: 0