A performance evaluation model for order picking warehouse design

This paper is concerned with a performance evaluation model for the order picking facility for warehouse design in a supply center (SC) by reducing the travel distance of transporters. This study includes important detail aspects of warehouse design and operational parameters such as warehouse size, rack size, number of transporters, and the system performance. In this study, we develop both mathematical and simulation modes considering probabilistic demand and picking frequency, and using simulation S/W, AutoMod. The results are compared and validated via simulation methods using AutoMod simulator. Finally, we developed a systematic and practical computer program and it was known that the proposed method is potentially efficient and useful in performance analysis for order picking warehouse problems.     

Dealing with complex queries in decision-support systems

In decision-making problems under uncertainty, a decision table consists of a set of attributes indicating what is the optimal decision (response) within the different scenarios defined by the attributes. We recently introduced a method to give explanations of these responses. In this paper, the method is extended. To do this, it is combined with a query system to answer expert questions about the preferred action for a given instantiation of decision table attributes. The main difficulty is to accurately answer queries associated with incomplete instantiations. Incomplete instantiations are the result of the evaluation of a partial model outputting decision tables that only include a subset of the whole problem, leading to uncertain responses. Our proposal establishes an automatic and interactive dialogue between the decision-support system and the expert to elicit information from the expert to reduce uncertainty. Typically, the process involves learning a Bayesian network structure from a relevant part of the decision table and computing some interesting conditional probabilities that are revised accordingly.     

A storage assignment heuristic method based on genetic algorithm for a pick-and-pass warehousing system

An order storage assignment problem (SAP) is to find an effective way to locate products in a warehouse in order to improve the operational efficiency of order picking. Since SAP is an NP-hard problem, many heuristic algorithms have been proposed. Most of previous researches focused on picker-to-parts warehousing systems or automated storage and retrieval systems. However, pick-and-pass systems play an important role for the faster delivery of small and frequent orders of inventory with the rise of e-commerce and e-business in the global supply chain. Two factors lead to idle time of pickers in a pick-and-pass system: picking line imbalance and shortage replenishment of products. This paper develops a genetic based heuristic method to solve SAP for a pick-and-pass system with multiple pickers to determine the appropriate storage space for each product and balance the workload of each picking zone so that the performance of the system can be improved. A simulation model based on FlexSim is used to implement the proposed heuristic algorithm and compare the throughput for different storage assignment methods as well. The results indicate that the proposed heuristic policy outperforms existing assignment methods in a pick-and-pass system.     

The effect of worker learning and forgetting on storage reassignment decisions in order picking systems

Order picking is a time-intensive and costly logistics activity as it involves a high amount of manual work. Prior research has mostly neglected the influence of human factors on the efficiency of order picking systems. This paper develops a mathematical model that investigates the impact of learning and forgetting of a heterogeneous workforce on order picking time and, consequently, on storage assignment decisions. In particular, the paper investigates when to change a storage assignment and when to keep it if learning and forgetting occur among the members of an order picking workforce. The results show that learning and forgetting should be considered in order to achieve a proper planning of storage assignment strategies.     

A heterogeneous multi-criteria multi-expert decision-support system for scoring combinations of flood mitigation and recovery options

In this study, we developed an innovative operational decision-support system (DSS) based on flood data and mitigation or recovery options, that can be used by both naïve and expert users to score portfolios of flood mitigation or recovery measures. The DSS combines exposure (i.e., economic, social, or environmental values at risk) and resilience (i.e., protection of the main equilibrium functions of human and physical systems). Experts from different fields define indices and functions, stakeholders express their attitudes towards risk, relative weights, and risk perceptions, and both groups use a shared learning process for risk assessment. The DSS algorithms include the “technique for order performance by similarity to ideal solution” (TOPSIS) and the “basic linguistic term set” (BLTS) methods for heterogeneous multi-criteria multi-expert decision-making. Decisions are illustrated using fixed or bounded values of flood depth, duration, and frequency, with plausible parameter values, for a case study of Cesenatico. The best mitigation option was construction of sand dunes and development of evacuation plans, which achieved 32% of the potential net benefit. The best recovery option was construction of sand dunes and development of evacuation plans and insurance schemes, which achieved 42% of the potential net benefit. Mitigation options outperformed recovery options whenever the relative importance of exposure with respect to resilience was greater than 95%. Sensitivity analysis revealed that the best mitigation option was most robust with respect to flood duration and depth; the best recovery option was most robust with respect to the relative weights attached to economic, social, and environmental factors. Both options were similarly robust with respect to interdependencies between the options.     

仓储电子标签辅助拣货系统的研究与设计

介绍了一种电子标签辅助拣货系统,提出了分层分级的设计思想,为大型仓储快速拣货的需要提供了可行的解决方案.设计了中间控制层和终端电子标签,系统通过RS485通信,指令数据传输稳定,通信距离远.     

An integrated model and a decomposition-based approach for concurrent layout and material handling system design

This paper presents an integer programming formulation that integrates decisions concerning the layout of the resource groups on the shop floor with the design of the material handling system. The model reflects critical practical concerns, including the capacity of the material flow network and of the handling transporters, as well as the tradeoff between fixed (construction and acquisition) and variable (operational) costs. For realistic industrial cases, the size of the problem prevents the solution using explicit or implicit enumeration methods. Instead, the global model is decomposed into standard optimization problems: quadratic assignment, fixed charge capacitated network design, and non-depot distance-constrained vehicle routing. An integrated solution method, guided by a simulated annealing scheme, solves the global shop design problem. The algorithm takes advantage of the proposed decomposition and converges to a final design which is feasible with respect to all problem constraints. The method is applied to redesign the facility of a large manufacturer of radar antennas. The resulting shop configuration exhibits substantially decreased material handling effort, and requires significantly smaller investment costs compared to the existing facility.     

Performance evaluation of two-worker operations in a worker-to-cell order assorting system

This paper studies an order assorting system (OAS) composed of multiple-parallel order assorting aisles (OAAs) in a retailer’s order fulfillment center. We evaluate two worker-assignment policies for a worker-to-part OAA: a dedicated-assignment policy and a shared-assignment policy. Our analytical models evaluate the mean value and variance of worker process time including assorting time, walk time, empty walk time, and blocking time when single-line products arrive randomly. From the worker process time, we identify the system flow time of product lines per each worker-assignment policy using G/G/1 and G/G/2 queuing models. We find that the shared-assignment policy performs better compared to the dedicated-assignment policy in spite of workers’ productivity losses incurred by blocking delays over high sort probability, slow walk speed, and high magnitude and variations of inter-arrival times. At the worker-centric break-even point of worker process time, where worker process time suggests selecting either policy, system flow time always suggests selecting the shared-assignment policy.     

A system design for surveillance systems protecting critical infrastructures

Critical infrastructures are attractive targets for attacks by intruders with different hostile aims. Modern information and sensor technology provides abilities to detect such attacks. The objective of this work is to outline a system design for surveillance systems aimed at protection of critical infrastructures, with the focus on early threat detection at the perimeter of critical infrastructures. The outline of the system design is based on an assessment of stakeholder needs. The needs were identified from interviews with domain experts and system operators. The system design of the surveillance system and the user requirements in terms of capabilities were then determined. The result consists of the system design for surveillance systems, comprising the systems capabilities, the systems structure, and the systems process. The outcome of the work will have an impact on the implementation of the surveillance systems with respect to the sensors utilized, the sensor data algorithms and the fusion techniques.     

Safe controllers design for industrial automation systems

The design of safe industrial controllers is one of the most important domains related to Automation Systems research. To support it, synthesis and analysis techniques are available. Among the analysis techniques, two of the most important are Simulation and Formal Verification. In this paper these two techniques are used together in a complementary way. Understanding plant behaviour is essential for obtaining safe industrial systems controllers; hence, plant modelling is crucial to the success of these techniques. A two step approach is presented: first, the use of Simulation and, second, the use of Formal Verification of Industrial Systems Specifications. The specification and plant models used for each technique are described. Simulation and Formal Verification results are presented and discussed. The approach presented in the paper can be applied to real industrial systems, and obtain safe controllers for hybrid plants. The Modelica modelling language and Dymola simulation environment are used for Simulation purposes, and Timed Automata formalism and the UPPAAL real-time model-checker are used for Formal Verification purposes.     

浅谈广电运营支撑系统的系统管理的设计与实现

从2009年广电大力推广NGBOSS的概念起,到国务院常务会议提出加快三网融合融合,再到三网融合融合写进政府工作报告,广电行业这两年可谓是风起云涌。NGB和三网融合的推出是从根本上改变广电网络运营市场环境体制和业务结构,广电网络运营商将从单一的节目传输运营商转变为综合信息服务提供商,这是实质上的一个转变。我们将新形势下的广电称为新广电,在三网融合时间表已经推出,三网融合试点城市即将推出之际,建设能够为新广电提供运营支撑的下一代综合业务运营支撑系统及新BOSS迫在眉睫。本文首先介绍了运营支撑系统的基本概念,并对运营支撑系统的系统管理功能模块进行设计与实现。     

Implementing a hybrid simulation model for a Kanban-based material handling system

Plant floor material handling is a loose loop in most assembly plants. Simulation offers a quick, controllable and tunable approach for prototyping complex material handling processes in manufacturing environments. This paper proposes a hybrid simulation approach, using both discrete event and agent-based technologies, to model complex material handling processes in an assembly line. A prototype system is implemented using a commercial multi-paradigm modeling tool. In this prototype, JIT principles are applied to both the production and the material handling processes. The system performance is evaluated and system optimization directions are suggested. The proposed hybrid modeling approach facilitates the implementation of a responsive and adaptive environment in that various “what-if” scenarios can be simulated under different simulation configurations and real-time situations.     

A psychophysical approach to determine the frequency and duration of work-rest schedules for manual handling operations

Abstract

The primary objectives of this study were: (1) to test whether rest allowances could be ascertained using a psychophysical methodology; and (2) to examine the effects of gender and frequency of handling on work-rest schedules. Two experiments were conducted, each experimental session at 4 h. A psychophysical methodology was used where the subject was given control of the working and resting durations. The results of the study indicated that: (1) the total working time decreased and the total resting time decreased with an increase in the frequency of handling; (2) high frequency tasks required more frequent rest allowances; (3) for the same manual handling tasks, women needed more frequent and longer allowances than men; (4) experience with the manual handling of material reduced the variability collected from the psychophysical methodology. The application of the psychophysical methodology in industry is discussed.     

A simulation methodology for a system of product life cycle systems

To realize environmental sustainability, the flow of natural resources into industrial systems must be reduced and stabilized at a suitable level. One way to reduce resource flows in society is to establish resource-circulating manufacturing systems. To foster the circulation of resources in industry, life cycle simulation (LCS) technologies, which are based on discrete-event modeling, have been developed to dynamically evaluate the life cycles of products from resource extraction to end of life from both environmental and economic aspects. In reality, various industrial products interact with each other in unanticipated ways, and then these interactions affect the material flows in product life cycles. This type of complex system is called a system of systems (SoS). Focusing on this issue, we expand the evaluation's system boundary to include a system of multiple product life cycle systems. To handle an SoS quantitatively, we introduce typical types of interactions between product life cycle systems. The purpose of this study was to propose a new LCS methodology, called “LCS4SoS,” that focuses on an SoS consisting of different kinds of product life cycle systems. A prototype system of LCS4SoS was implemented based on this proposed methodology. Through a case study, it was found that the proposed methodology is useful for evaluating an SoS consisting of multi-product life cycle systems.     

Advanced material handling system for computer integrated manufacturing

A cordless linear synchronous motor (LSM) material handling system for CIM has been developed. The system incorporates a courier that moves without tether restrictions. This provides for an automated material handling system with improved travel and flexibility. The material handling system runs on an integrated reverse air bearing system which eliminates friction and backlash. The proposed system forms part of a manufacturing assembly, interacting with overhead manipulators and part feeders to form a comprehensive production system. The design and implementation of the cordless linear motor material handling system (MHS) is outlined and described in the paper.     

工业控制系统信息安全管理措施研究

由于当前工业控制系统正面临着严峻的信息安全风险,作为国家经济命脉的重要基础设施,工业控制系统必须要进行系统信息安全防护建设。本文在对工业控制系统信息安全和信息安全风险来源分析的基础上,从管理的角度提出了相关的建议措施。     

RFID技术在物流自动化管理系统中的应用

本文综合应用RFID技术、网络通信、COM接口、OPC通信、MD5加密算法和VS.NETC#编程等技术设计实现了一个仓储物流自动化管理系统。该系统通过RFID读写器实现了对电子标签的读写;采用OPC技术与组态软件WinCC进行通信,通过对PLC的控制实现了对物流系统的控制;对数据库SQLServer访问,完成了物品信息、仓库信息、客户信息、操作记录、登录信息的自动存储、查询删除等功能。本文为电子标签技术、物流控制及物流管理的结合提供了应用基础。     

切削刀具综合管理系统的数据采集和存储设计研究*

为建立满足汽车发动机制造企业需求的切削刀具综合管理系统,本文研究了该系统数据库的基础数据采集和存储问题。针对生产现场数据采集困难的问题,设计基于射频识别技术的数据采集方法,提高采集的效率和数据的可靠度。提出刀具与工步对应的存储方法,将刀具信息与生产线相应信息有效衔接。建立系统E-R模型,应用关系规范化理论进行数据存储分析,设计数据表及其相互关系,解决数据库存储的冗余问题。以上述研究成果为基础建立切削刀具数据库,并验证数据库企业实施的可行性。研究成果为建立具有高可靠性和操作性的刀具综合管理系统提供了理论和实践保障。