Chin-Chia Wu

• Professor
• Feng Chia University

Many uncertainties arise during the manufacturing process, such as changes in the working environment, traffic transportation delays, machine breakdowns, and worker performance instabilities. These factors can cause job processing times and ready times to change. In this study, we address a scheduling model for a single machine where both job relea...

The manufacturing sector faces unprecedented challenges, including intense competition, a surge in product varieties, heightened customization demands, and shorter product life cycles. These challenges underscore the critical need to optimize manufacturing systems. Among the most enduring and complex challenges within this domain is production sche...

Multiple-job-class sequencing problems solve a group of jobs belonging to multiple classes, where to decrease the processing time, jobs in the same class tend to be performed together with the same setup time. In contrast, customer order scheduling problems focus on completing all jobs (belonging to different classes) in the same order at the same...

This paper delves into the scheduling of the two-machine flow-shop problem with step-learning, a scenario in which job processing times decrease if they commence after their learning dates. The objective is to optimize resource allocation and task sequencing to ensure efficient time utilization and timely completion of all jobs, also known as the m...

In this study we address some two-agent scheduling models with proportionally-linear deteriorated jobs, which the job processing time is assumed as an non-decreasing linear function of its starting time. Our goal is to find a job sequence in which the objective functions of agent A are minimized, satisfied that the objective functions of agent B ca...

The multiple job class scheduling problem arises in contexts where a group of jobs belong to multiple classes and in which if all jobs in the same class are operated together, extra setup times would not be needed. On the other hand, the customer order scheduling problem focuses on finishing all jobs from the same order at the same time in order to...

This paper studies a distributionally robust joint chance-constrained program with a hybrid ambiguity set including the Wasserstein metric, and moment and bounded support information of uncertain parameters. For the considered mathematical program, the random variables are located in a given support space, so a set of random constraints with a high...

Cloud computing is widely applied in modern industrial areas due to its technological advancement, cost reduction, and applicability. Packets (tasks) belonging to different applications (agents) compete to share the common cloud resource through a series of edge nodes (processors) in pursuit of fast transmission. This paper abstracts the cloud comp...

Among the well-known scheduling problems, the customer order scheduling problem (COSP) has always been of great importance in manufacturing. To reflect the reality of COSPs as much as possible, this study considers that jobs from different orders are classified in various classes. This paper addresses a tri-criteria single-machine scheduling model...

Studies on the customer order scheduling problem have been attracting increasing attention. Most current approaches consider that either component processing times for customer orders on each machine are constant or all customer orders are available at the outset of production planning. However, these assumptions do not hold in real-world applicati...

Accurate forecasting of taxi demand has facilitated the rational allocation of urban public transport resources, reduced congestion in urban transport networks, and shortened passenger waiting time. However, virtual station discovery and modelling of the demand when forecasting through graph convolutional neural networks remains challenging. In thi...

A method was proposed for enhancing the energy absorption of hollow-cylinder rubber (HCR) fenders by introducing V-notch ring grooves at the top and bottom of the fender structure. The feasibility of the proposed approach was investigated experimentally by compression tests on scaled HCR fenders with four notch height positions (6, 8, 10, and 12 mm...

In a flowshop, the current stage has to remain work-in-process and cannot release any task to the downstream stage once the buffer is stuffed. This scheduling phenomenon is called blocking, and it usually occurs in an industrial setting because of the buffer capacity or the product volume. This study addresses several blocking flowshop scheduling p...

Time-dependent scheduling problems, where the real processing time of jobs is dependent on the starting time, have received growing attention in recent decades. In particular, scheduling problems on a single machine have been widely studied in many facets that address the learning effect and diverse processing environments or time-dependent process...

In many real-world environments, machine breakdowns or worker performance instabilities cause uncertainty in job processing times, while working environment changes or transportation delays will postpone finished production for customers. The factors that impact the task processing times and/or deadlines vary. In view of the uncertainty, job proces...

Although some uncertainty factors can occur in many practical environments, customer order scheduling problems involving two agents in such uncertain environments have not received attention in the current literature. Motivated by this observation, we address a two-agent customer order scheduling problem where various customer orders have scenario-...

In modern manufacturing and services, rescheduling frequently happens in manufacturing practice, which a disruption may happen. In this paper, the rescheduling problem with the unexpected new jobs arrival is studied, and the effect of time disruptions is taken into account on a previously planned optimal schedule. Rescheduling means that a set of o...

Flow-shop scheduling is an extremely popular optimization model in industrial production, where each job must be scheduled on a series of machines following an identical process. The optimal criteria, makespan and maximum delivery–completion time, are investigated separately. A mixed integer programming model is built to evaluate the exact algorith...

Customer satisfaction is a prevalent issue amongst manufacturing enterprises. Multi-agent scheduling models aim to optimise the given criteria for improving customer satisfaction by fulfilling the customisation requirements. An investigation is executed on a bi-agent flowshop scheduling model, where a mass of tasks maintained by two competitive age...

This paper studies the slack due-window assignment method for single-machine scheduling problems with position-and resource-dependent processing times, for which the actual processing time is a continuous bivariate non-increasing convex function involving position and resource allocation. Only the slack due-window assignment method will be used. Tw...

This paper studies a single-machine multitasking scheduling problem together with two-agent consideration. The objective is to look for an optimal schedule to minimize the total tardiness of one agent subject to the total completion time of another agent has an upper bound. For this problem, a branch-and-bound method equipped with several dominant...

The customer’s order (CO) issues have received growing attention in the scheduling research community. In the CO design, a customer’s order consists of several components, and the processed orders are assigned to m parallel machines. The completion time of an order is assumed at the time at which all components in a customer’s order are finished. I...

Recently, the setup times or costs have become an important research topic. The main reason is huge economic savings can be achieved when setup times are explicitly included in scheduling decisions in various real-world industrial environments. On the other hand, many real systems commonly face various uncertainties, such as working environment cha...

For the split delivery vehicle routing problem in the distribution link of logistics where the optimization objective is to minimize the total distance of the transportation path, a hybrid discrete differential evolution (HDDE) algorithm is adopted in this study. The algorithm applies the encoding and decoding method based on the remaining vehicle...

Many practical productions are full of significant uncertainties. For example, the working environment may change, machines may breakdown, workers may become unstable, etc. In such an environment, job processing times should not be fixed numbers. In light of this situation, we investigate a single-machine problem with two-scenario-based processing...

Manufacturing industry reflects a country’s productivity level and occupies an important share in the national economy of developed countries in the world. Jobshop scheduling (JSS) model originates from modern manufacturing, in which a number of tasks are executed individually on a series of processors following their preset processing routes. This...

The two-stage assembly scheduling problem has a lot of applications in industrial and service sectors. Furthermore, truncation-based learning effects have received growing attention in connection with scheduling problems. However, it is relatively unexplored in the two-stage assembly scheduling problem. Therefore, we addressed the two-stage assembl...

Recently, finding solutions to assembly flowshop scheduling problems is a topic of extensive discussion in research communities. While existing research assumes that job processing times are constant numbers, in several practical situations, due to several external factors like machine breakdowns, working environment changes, worker performance ins...

In many scheduling studies, researchers consider the processing times of jobs as constant numbers. This assumption sometimes is at odds with practical manufacturing process due to several sources of uncertainties arising from real-life situations. Examples are the changing working environments, machine breakdowns, tool quality variations and unavai...

A theoretical investigation is performed into the bending behavior of FOF-ACF (Flex-On-Flex bonded by Anisotropic Conductive Film) packages bonded at different positions relative to the neutral surface position. The stresses and strains produced in the upper and lower regions of the ACF layer are investigated using Mode I fracture mechanics theory....

This study examines a two-stage three-machine flow-shop assembly scheduling model in which job processing time is considered as a mixed function of a controlled truncation parameter with a sum-of-processing-times-based learning effect. However, the truncation function is very limited in the two-stage flow-shop assembly scheduling settings. To overc...

Multi-variety and small-batch productions are usually undertaken by skilled workers instead of an automatic assembly line because of economic cost consideration. In the production process, a worker's familiarity to an operation influences the length of task execution time. An interesting phenomenon called learning effect has become a trending resea...

This paper studies linear deteriorating jobs and maintenance activities under the potential disrupted parallel machines. Potential disruption means that there exists an unavailable interval at a particular time under a certain probability on some machine. We consider the resumable case and the non-resumable case when a machine becomes available aga...

Researchers claim that the processing of most products can be formulated as a two-stage assembly scheduling model. The literature states that cumulative learning experience is neglected in solving two-stage assembly scheduling problems. The sum-of-processing-times-based learning effect means that the actual processing time of a job becomes shorter...

In this study, the effect of wall thickness (15–25 mm) on the stress–strain response of hollow-cylinder rubber fenders were investigated by conducting monotonic compression tests. It was found that a progressive increase in lateral bending deformation was observed during monotonic compression. Simultaneously, the extent of the lateral deflection de...

In this paper, we propose a novel tabu search (NTS) algorithm that improves the efficiencies of picking goods of automated guided vehicles (AGVs) in an automatic warehouse by solving the conflicts that happen when multiple AGVs work at the same time. Relocation and exchanging operations are designed for the neighborhood searching process based on e...

This paper introduces a two-stage assembly flowshop scheduling model with time cumulated learning effect, which exists in many realistic scheduling settings. By the time cumulated learning effect, we mean that the actual job processing time of a job depends on its scheduled position as well as the processing times of the jobs already processed. The...

The order scheduling models have kept growing attention in the research community. However, as studying research regarding order scheduling models with release dates is relatively limited; this study addresses an order scheduling problem with release dates where the objective function is to minimize the weighted number of tardy orders of all the gi...

This article addresses a two-stage, three-machine assembly scheduling problem that considers the learning effect. All jobs are processed on two machines in the first stage and move on to be processed on an assembly machine in the second stage. The objective of the study is to minimize the total completion time of the given jobs. Because the problem...

The two-stage assembly scheduling problem has received growing attention in the research community. Furthermore, in many two-stage assembly scheduling problems, the job processing times are commonly assumed as a constant over time. However, it is at odds with real production situations some times. In fact, the dynamic nature of processing time may...

Two-stage three-machine assembly flow shop, multiple-agent scheduling problems, and scheduling models with time-dependent processing times have been separately receiving continuous attention on research community. All the three phenomena have been shown to exist in many real applications, but no study has so far integrated the two-stage assembly fl...

The study was devoted to the observation and modeling the mechanical behaviors of a hybrid SBR/NR (Styrene-Butadiene/Natural Rubber) hybrid vulcanized rubber fender under monotonic/cyclic compression. In experimental observations of the monotonic compression tests, it was found that lateral deformation occurred on the tested fender and was more sig...

This paper considers several integrated production, inventory, and batch delivery scheduling problems on a single machine with due date assignment and two competing agents, each of which seeks to optimize its own performance. All the jobs of the first agent have a common due date, which is a decision variable to be determined by the decision maker,...

The customer order scheduling problem is becoming a major topic in the research community, but the research regarding customer order scheduling problems with ready times remains relatively limited. This study examined an order scheduling problem with ready times where the measurement criterion was minimizing the total weighted completion time of al...

In recent years, various customer order scheduling (OS) models can be found in numerous manufacturing and service systems in which several designers, who have developed modules independently for several different products, convene as a product development team, and that team completes a product design only after all the modules have been designed....

This paper studies a two-agent single-machine scheduling problem with sum-of-processing-times-based learning consideration. The goal is to find an optimal schedule to minimize the total late work of the first agent subject to the restriction that the maximum lateness of the second agent has an upper bound. For this problem, a branch-and-bound algor...

In this study we address several two-agent problems in which the measure criterion is to minimize the maximum cost or total weighted completion of all the jobs, while subject to an upper bound on the maximum cost of agent A. In term of minimizing the maximum cost of all the jobs subject to an upper bound on the maximum cost of agent A, we discuss s...

During solving scheduling problems in a manufacturing system, the processing time of a job is commonly assumed to be independent of its position in a scheduling sequence. However, this independence assumption may not adequately reflect many real manufacturing situations. In fact, the job processing time usually steadily decreases as the process pro...

An order scheduling problem arises in numerous production scheduling environments. Makespan, mean flow time, and mean tardiness are the most commonly discussed and studied measurable criteria in the research community. Although the order scheduling model with a single objective has been widely studied, it is at odds with real-life scheduling practi...

There have been many applications of two-stage three-machine assembly flow shop in query scheduling, such as fire engine assembly, personal computer manufacturing, and distributed database system. Moreover, learning phenomenon has been shown present in many two-stage assembly flow shop environments. In conjunction with this learning phenomenon, we...

The assembly of numerous applications can proceed only if all the parts for assembly are available. The completion time is determined largely by the time of manufacture of the final component. The setup times are included in the job processing time. It is unreasonable to assume that the setup process dominates the overall production process. Such a...

The two-stage assembly scheduling problem has attracted increasing research attention. In many such problems, job processing times are commonly assumed to be fixed. However, this assumption does not hold in many real production situations. In fact, processing times usually decrease steadily when the same task is performed repeatedly. Therefore, in...

Most research studies on scheduling problems assume that a job visits certain machines only one time. However, this assumption is invalid in some real-life situations. For example, a job may be processed by the same machine more than once in semiconductor wafer manufacturing or in a printed circuit board manufacturing machine. Such a setting is kno...

In this study, a single-machine scheduling and due-window assignment problem is addressed. In the proposed model, the job processing time is assumed a linear function of its starting time and all the n job-independent deterioration rates are the same. In addition, an option is considered for performing a rate-modifying activity for changing the nor...

We consider the scheduling problem in which two agents (agents A and B), each having its own job set (containing the A-jobs and B-jobs, respectively), compete to process their own jobs in a two-machine flowshop. Each agent wants to maximize a certain criterion depending on the completion times of its jobs only. Specifically, agent A desires to maxi...

This paper studies a single-machine due date assignment and scheduling problem in a disruptive environment, where a machine disruption may occur at a particular time that will last for a period of time with a certain probability, and the job due dates are determined by the decision-maker using the popular common due date assignment method. The goal...

In this article, a competitive two-agent scheduling problem in a two-machine open shop is studied. The objective is to minimize the weighted sum of the makespans of two competitive agents. A complexity proof is presented for minimizing the weighted combination of the makespan of each agent if the weight α belonging to agent B is arbitrary. Furtherm...

This paper studies some scheduling problems with general truncated sum-of-processing time dependent effect under single machine and unrelated parallel machines. Under the single machine, we consider that the actual processing time of a job is bivariate, continuous and non-increasing convex function of the total processing time of the processed jobs...

This paper addresses single-machine batch scheduling with job rejection and convex re- source allocation. A job is either rejected, in which case a rejection penalty will be incurred, or accepted and processed on the machine. The accepted jobs are combined to form batches containing contigu- ously scheduled jobs. For each batch, a batch-dependent m...

When the workers carry out the operation of many tasks, they will be fatigued. Meanwhile, the experience performance will also be degraded over time owe to mal-position or mal-alignment of jobs, abrasion of tools, etc. The maintenance activities will be required to maintenance acceptable production rates. In this study, some machine scheduling prob...

Job precedence can be found in some real-life situations. For the application in the scheduling of patients from multiple waiting lines or different physicians, patients in the same waiting line for scarce resources such as organs, or with the same physician often need to be treated on the first-come, first-served basis to avoid ethical or legal is...

This paper addresses a two-agent scheduling problem where the objective is to minimize the total late work of the first agent, with the restriction that the maximum lateness of the second agent cannot exceed a given value. Two pseudo-polynomial dynamic programming algorithms are presented to find the optimal solutions for small-scale problem instan...

In the more recent days, topics of scheduling re-entrant flowshop settings and scheduling models with learning consideration have received growing attention separately in research areas. However, scheduling with both the learning and re-entrant concept is relatively unexplored. Motivated by this limitation, this paper considers re-entrant permutati...

This study examines the technical efficiency and environmental efficiency of bus transit firms using the slack-based measures (SBM) and non-separable slack-based measures (NSSBM) models with and without considerations of desirable and undesirable outputs. A case study based on data from 12 bus transit firms for the years 2007 to 2011 was conducted....

We consider integrated scheduling of production and distribution operations associated with two customers (agents). Each customer has a set of orders to be processed on the single production line at a supplier on a competitive basis. The finished orders of the same customer are then packed and delivered to the customer by a third-party logistics (3...

This paper studies linear non-increasing processing times and the common/slack due window assignment problems on a single machine, where the actual processing time of a job is a linear non-increasing function of its starting time. The aim is to minimize the sum of the earliness cost, tardiness cost, due window location and due window size. Some opt...

Recently, both the learning effect scheduling and re-entrant scheduling have received more attention separately in research community. However, the learning effect concept has not been introduced into re-entrant scheduling in the environment setting. To fill this research gap, we investigate re-entrant permutation flowshop scheduling with a positio...

Due to its simplicity yet powerful search ability, iterated local search (ILS) has been widely used to tackle a variety of single-objective combinatorial optimization problems. However, applying ILS to solve multi-objective combinatorial optimization problems is scanty. In this paper we design a multi-objective ILS (MOILS) to solve the multi-object...

This paper addresses a scheduling problem in a flexible supply chain where the jobs can be either processed in house, or outsourced to a third-party supplier with the goal of minimizing the sum of holding and delivery costs subject to an upper bound on the outsourcing cost. The problem with identical job processing times has been proved as binary (...

Recently, multi-agent scheduling and customer order scheduling have separately received much attention in scheduling research. However, the two-agent concept has not been introduced into order scheduling in the multi-facility setting. To fill this research gap, we consider in this paper two-agent multi-facility order scheduling with ready times. Th...

Scheduling problems with learning effects have been widely studied in numerous publication. However, the learning effect might accelerate, especially in the steel plates and the human interaction systems. In this paper, we propose a new scheduling model with a learning effect matrix. We show that the makespan and the total completion time problems...

This paper considers a scheduling model involving two agents, job release times, and the sum-of-processing-times-based learning effect. The sum-of-processing-times-based learning effect means that the actual processing time of a job of either agent is a decreasing function of the sum of the processing times of the jobs already scheduled in a given...

We consider scheduling problems involving two agents (agents A and B), each having a set of jobs that compete for the use of a common machine to process their respective jobs. The due dates of the A-jobs are decision variables, which are determined by using the common (CON) or slack (SLK) due date assignment methods. Each agent wants to minimize a...

In this study, experimental observations have been performed to understand the cyclic stress-amplitude response, the cyclic hardening/softening characteristics and the cyclic fatigue properties of AISI 316 stainless steel. Based on the experimental observations, these results are found so that the tested AISI 316 stainless steel possesses cyclic ha...

There is a situation found in many manufacturing systems, such as steel rolling mills, fire fighting or single-server cycle-queues, where a job that is processed later consumes more time than that same job when processed earlier. The research finds that machine maintenance can improve the worsening of processing conditions. After maintenance activi...

The order scheduling problem is receiving increasing attention in the relatively new but creative area of scheduling research. In order scheduling, several orders are processed on multiple machines, and each order comprises multiple components. The order completion time is defined as the time at which all components in an order are completed. In pr...

We consider the problem of scheduling n independent and simultaneously available jobs without preemption on a single machine, where the machine has a fixed maintenance activity. The objective is to find the optimal job sequence to minimize the total amount of late work, where the late work of a job is the amount of processing of the job that is per...

This paper addresses single-machine scheduling and due-window assignment with common flow allowances and resource-dependent processing times. Due-window assignment with common flow allowances means that each job has a job-dependent due window, the start time and finish time of which are equal to its actual processing time plus individual job-indepe...

In many resource allocation problems in physical or economic systems, a linear resource consumption function is commonly considered, and job processing times are assumed to be fixed parameters. However, the former assumption fails to reflect the law of diminishing returns, and the latter may be controlled by changing the allocation of resources to...

We consider integrated production and batch delivery scheduling in a make-to-order production system involving two competing agents, each of which having its own job set competes to process its jobs on a shared single machine. To save the delivery cost, the jobs of the same agent can be processed and delivered together batches. The completion time...

This paper addresses some scheduling problems with two competing agents, called agents A and B, respectively, each of which has a set of independent nonpreemptive jobs to be scheduled for processing on a common machine. The due dates of jobs in each job set are considered as given parameters and must be assigned to individual jobs. Each agent wants...

This paper considers a two-agent scheduling problem with arbitrary release dates on a single machine. The cost of the first agent is the maximum weighted completion time of its jobs while the cost of the second agent is the total weighted completion time of its jobs. The goal is to schedule the jobs such that the total cost of the two agents is min...