Rescheduling Capabilities Research Articles

Development of a multidimensional conceptual model for job shop smart manufacturing scheduling from the Industry 4.0 perspective

Based on a scientific literature review in the conceptual domain defined by smart manufacturing scheduling (SMS), this article identifies the benefits and limitations of the reviewed contributions, establishes and discusses a set of criteria with which to collect and structure its main synergistic attributes, and devises a conceptual framework that models SMS around three axes: a semantic ontology context, a hierarchical agent structure, and the deep reinforcement learning (DRL) method. The main purpose of such a modelling research is to establish a conceptual and structured relationship framework to improve the efficiency of the job shop scheduling process using the approach defined by SMS. The presented model orients the job shop scheduling process towards greater flexibility, through enhanced rescheduling capability, and towards autonomous operation, mainly supported by the use of machine learning technology. To the best of our knowledge, there are no other similar conceptual models in the literature that synergistically combine the potential of the specific set of Industry 4.0 principles and technologies that model SMS. This research can provide guidance for practitioners and researchers’ efforts to move toward the digital transformation of job shops.

A Lean Approach for Real-Time Planning and Monitoring in Engineer-to-Order Construction Projects

Engineer-to-order (ETO) construction companies are characterized by an off-site and on-site production. Often, budget deviations for installation works on-site are identified in a late stage when improvement actions cannot be applied anymore. Consequently, installation tasks are often affected by significant delays and/or reworks. This work proposes a “real-time” capable approach for planning and monitoring in construction and a corresponding information technology (IT) framework. The core is represented by the so-called “pitching” concept known from lean management, which breaks down large job orders into smaller controllable parts. It can be considered as the main enabler for gathering management information in real-time and to identify problems and their causes on time. The most noticeable consequence lies in smaller jobs and a software-aided punctual control that allows a better rescheduling capability and, thus reduced, delays. A case study is provided, showing how the model was applied and validated in an ETO façade supplier company.

Reactive Scheduling of a Decentralized Multi-Objective Material Transportation Tasks in a Dynamic Job Shop Manufacturing System

The increasingly challenging and dynamic nature of manufacturing industry has driven organizations to enhance their system efficiency. One of the most important aspects in manufacturing plant is the Material Transportation System (MTS). In order to address dynamic factors, MTS need to be equipped with rescheduling capability. This paper focuses on reactive transportation task assignment to a fleet of autonomous Automated Guided Vehicles (AGVs). This paper proposes a Mixed Integer Programming method to reschedule transportation tasks for a non-disruptive job shop manufacturing system based on Multi Agent System (MAS) architecture. The result shows that proposed rescheduling method is able to outperform conventional method significantly.

Tourist Activity Simulation Model for Assessing Real-Time Tour Information Systems

The purpose of this article is to develop a framework for assessing the effects of tour information systems and information dissemination strategies by incorporating tourists’ decision processes into an activity-based model. There are two important features in tourists’ decision-making processes: (1) They generally have limited information and experiences on tour sites, and (2) their value of time is higher than normal travelers' because of their time limitations. These two features are, however, the main reasons that make tour information services attractive to tourists and thus should also be incorporated into a modeling framework for investigating the effects of the real-time tour information system. This study develops an agent-based simulation model that incorporates activity chaining behavior into tour scheduling systems. The underlying assumption used in the model is that tourists schedule their activities within their time and budget constraints to maximize their utilities. The model seeks individuals’ optimal tour schedules by solving a prize-collecting multiple-day traveling salesman problem (PC-MD-TSP). The simulation model also includes real-time and end-of-day rescheduling capabilities by taking tourists’ unpredicted delays into consideration. From a numerical test, the pros and cons of tour information services are found and the optimal strategy for a tour information service is also discussed. The results show that tour information services increase tourists’ satisfaction with less expenditure by allowing tourists to visit more places in an effective way.

Low-cost fault tolerance in evolvable multiprocessor systems: a graceful degradation approach

The evolvable multiprocessor (EvoMP), as a novel multiprocessor system-on-chip (MPSoC) machine with evolvable task decomposition and scheduling, claims a major feature of low-cost and efficient fault tolerance. Non-centralized control and adaptive distribution of the program among the available processors are two major capabilities of this platform, which remarkably help to achieve an efficient fault tolerance scheme. This letter presents the operational as well as architectural details of this fault tolerance scheme. In this method, when a processor becomes faulty, it will be eliminated of contribution in program execution in remaining run-time. This method also utilizes dynamic rescheduling capability of the system to achieve the maximum possible efficiency after processor reduction. The results confirm the efficiency and remarkable advantages of the proposed approach over common redundancy based techniques in similar systems.

Handling fuzzy temporal constraints in a planning environment

An interleaved integration of the planning and scheduling process is presented with the idea of including soft temporal constraints in a partial order planner that is being used as the core module of an intelligent decision support system for the design forest fire fighting plans. These soft temporal constraints have been defined through fuzzy sets. This representation allows us a flexible representation and handling of temporal information. The scheduler model consists of a fuzzy temporal constraints network whose main goal is the consistency checking of the network associated to each partial order plan. Moreover, we present a model of estimating this consistency, and show the monitoring and rescheduling capabilities of the system. The resulting approach is able to tackle problems with ill defined knowledge, to obtain plans that are approximately consistent and to adapt the execution of plans to unexpected delays.

Supporting rescheduling using CSP, RMS and POB—an example application

This paper introduces an innovative approach to the problem of rescheduling within manufacturing industry. An example of a manufacturing context that requires rescheduling capability is given (tyre production). The meaning of rescheduling, possible metrics for assessment of rescheduling and the advantages of applying the new techniques are reviewed. Of particular importance is the notion that the technology for providing rescheduling and explanation capabilities is to a large degree problem and context insensitive. The manner in which an original schedule has been created is irrelevant to the use of the technology described, allowing the advantages of the approach to be realized as an add-on facility to any existing scheduling system that fulfills a minimal set of requirements. These advantages are due to the use of a constraint based approach to new schedule creation used in tandem with dependency analysis techniques based on reason maintenance systems (de Kleer, 1986) and partial order backtracking (Ginsberg and McAllister, 1995; Spragg and Kelleher, 1996).

Adopting Rescheduling Capability in DRP to Deal with Operational Uncertainty in Logistics Systems

Safety stock, safety lead time, and safety capacity are the conventional methods used to deal with operational uncertainty. With the advent of material requirements planning (MRP) systems, the rescheduling capability can be viewed as an alternative to buffer production systems against uncertainty. Logistics systems have characteristics similar to production systems in the face of uncertain events occurred in the operating environments. After presenting the rescheduling capability of a counterpart of MRP in logistics systems, distribution resource planning (DRP), as a viable uncertainty buffering method, we discuss the operational implications of these buffering methods from the perspectives of (1) the nature of the business, (2) the decision‐making hierarchy, (3) the cost of implementation, and (4) the impact of operating environments in logistics systems. The discussion on operational implications should lead to a better understanding regarding how to evaluate these buffering methods in logistics systems.

Optimal short term hydro scheduling including security constraints

A method is presented for short-term production scheduling in a hydro system. The solution technique is based on iterative network linear programming and heuristic techniques. The method handles security constraints due to single branch and specified multiple contingencies. The postcontingency rescheduling capabilities are modeled explicitly in a DC optimal load flow. Using the rescheduling capabilities increases the transmission network utilization.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A sequencing heuristic for dependent setups in a batch process industry

Microcomputer-based scheduling systems are dramatically enhancing the ability of manufacturing firms to respond rapidly to changing customer demands and to improve production efficiency. Pendegraft [11], Sullivan and Secrest [14], and Hodsen, Muhlemann and Price [7] provide examples of optimizing schemes that are microcomputer-based. These systems, though do not address sequencing problems with dependent setups nor do they provide efficient rescheduling capabilities required by many practical scheduling environments. This paper presents the development and application of a heuristic approach for scheduling jobs on parallel processors given sequence dependent changeover costs. The model provides for simultaneous processing of single or multiple products, the latter of particular concern in the batch process industries where machine utilization is of immediate concern. An industrial application of the sequencing heuristic at a fiberglass company indicates that cost savings arising from reduced setups can be accrued from the use of the model. The sequencing heuristic is easily understood in terms of its solution methodology and thus more likely to appeal to actual production schedulers.

Security Constrained Dispatch with Post-Contingency Corrective Rescheduling Using Linear Programming

The objective of a security constrained dispatch is to minimize the operational cost of an electric power network to meet immediate future load demand satisfying various physical and operational constraints for the normal and post-contingency system state. It has been recognised for some years that the solution obtained for such a dispatch is pessimistic as it does not take into account the post-contingency corrective capability of the system. This paper describes a solution method, using a Sparse Dual Revised Simplex algorithm, which can efficiently include the corrective rescheduling capability of the generating units. Because the solution technique is based on linear programming, the method is inherently reliable, fast and robust. A simple formula to obtain the post-disturbance system sensitivity matrix in terms of pre-outage sensitivity matrix is also derived. Results included for a 115-unit system show that very significant saving can be achieved when the rescheduling capability of the system is included in the dispatch algorithm and that the proposed approach is practical for real-time large system applications.