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Dynamic Scheduling With Uncertain Job Types, Zuo-Jun Max Shen, Jingui Xie, Zhichao Zheng, Han Zhou
Dynamic Scheduling With Uncertain Job Types, Zuo-Jun Max Shen, Jingui Xie, Zhichao Zheng, Han Zhou
Research Collection Lee Kong Chian School Of Business
Uncertain job types can arise as a result of predictive or diagnostic inaccuracy in healthcare or repair service systems and unknown preferences in matching service systems. In this paper, we study systems with multiple types of jobs, in which type information is imperfect and will be updated dynamically. Each job has a prior probability of belonging to a certain type which may be predicted by data, models, or experts. A job can only be processed by the right machine, and a job assigned to the wrong machine must be rescheduled. More information is learned from the mismatch, and job type …
Limousine Service Management: Capacity Planning With Predictive Analytics And Optimization, Peng Liu, Ying Chen, Chung-Piaw Teo
Limousine Service Management: Capacity Planning With Predictive Analytics And Optimization, Peng Liu, Ying Chen, Chung-Piaw Teo
Research Collection Lee Kong Chian School Of Business
The limousine service in luxury hotels is an integral component of the whole customer journey in the hospitality industry. One of the largest hotels in Singapore manages a fleet of both in-house and outsourced vehicles around the clock, serving 9,000 trips per month on average. The need for vehicles may scale up rapidly, especially during special events and festive periods in the country. The excess demand is met by having additional outsourced vehicles on standby, incurring millions of dollars of additional expenses per year for the hotel. Determining the required number of limousines by hour of the day is a …
Ad Revenue Optimization In Live Broadcasting, Dana G. Popescu, Pascale Crama
Ad Revenue Optimization In Live Broadcasting, Dana G. Popescu, Pascale Crama
Research Collection Lee Kong Chian School Of Business
In live broadcasting, the break lengths available for commercials are not always fixed and known in advance (e.g., strategic and injury time-outs are of variable duration in live sports transmissions). Broadcasters actively manage their advertising revenue by jointly optimizing sales and scheduling policies. We characterize the optimal dynamic schedule in a simplified setting that incorporates stochastic break durations and advertisement lengths of 15 and 30 seconds. The optimal policy is a "greedy" look-ahead rule that accounts for the remaining number of breaks; in this setting, there is no value to perfect information at the scheduling stage, and hence knowing the …
Vehicle Minimization For The Multimodal Pickup And Delivery Problem With Time Windows, Benjamin A . Clapp
Vehicle Minimization For The Multimodal Pickup And Delivery Problem With Time Windows, Benjamin A . Clapp
Theses and Dissertations
The algorithm proposed here is used for heuristic solutions for the Multimodal Multiple Vehicle Routing Problem with Unloading Capacity, Pickup and Dropoff, and Time Windows, solved so as to minimize the number of vehicles used, subject to varying objective function values for each vehicle. The MVRP is simplified and split into a routing problem and a scheduling problem. The routing problem is addressed by Dijkstra's Algorithm. This generates a new network for the second stage of the algorithm. It is assumed that the shortest path is the correct path to use, and shipments each travel unimodally. The scheduling problem is …
Conditional Lot Splitting To Avoid Setups While Reducing Flow Time, Jacob V. Simons, Mark E. Kraus, Willis Mwangola, Gerard Burke
Conditional Lot Splitting To Avoid Setups While Reducing Flow Time, Jacob V. Simons, Mark E. Kraus, Willis Mwangola, Gerard Burke
Department of Logistics & Supply Chain Management Faculty Publications
Previous research has clearly and consistently shown that flow time advantages accrue from splitting production lots into smaller transfer batches or sub-lots. Less extensively discussed, and certainly undesired, is the fact that lot splitting may dramatically increase the number of setups required, making it impractical in some settings. This paper describes and demonstrates a primary cause of these “extra” setups. It then proposes and evaluates decision rules which selectively invoke lot splitting in an attempt to avoid extra setups. For the closed job shop environment tested, our results indicate that conditional logic can achieve a substantial portion of lot splitting’s …
Dynamic Allocation Of Airline Check-In Counters: A Queueing Optimisation Approach, Mahmut Parlar, Sharafali Moosa
Dynamic Allocation Of Airline Check-In Counters: A Queueing Optimisation Approach, Mahmut Parlar, Sharafali Moosa
Research Collection Lee Kong Chian School Of Business
This paper was motivated by an observation in an international airport with regard to allocation of resources for check-in counters. In an exclusive check-in counter system, each flight has a dedicated number of counters that will be open until at least a half-hour before the scheduled departure of that flight. Currently, in many of the airports around the world, the decision to open or close check-in counters is done on an ad hoc basis by human schedulers. In doing so, the schedulers are almost always forced to perform a balancing act in meeting the quality of service stipulated by the …
Optimization Model For Base-Level Delivery Routes And Crew Scheduling, Young-Ho Cha
Optimization Model For Base-Level Delivery Routes And Crew Scheduling, Young-Ho Cha
Theses and Dissertations
In the U.S. Air Force, a Logistic Readiness Squadron (LRS) provides material management, distribution, and oversight of contingency operations. Dispatchers in the LRS must quickly prepare schedules that meet the needs of their customers while dealing with real-world constraints, such as time windows, delivery priorities, and intermittent recurring missions. Currently, LRS vehicle operation elements are faced with a shortage of manpower and lack an efficient scheduling algorithm and tool. The purpose of this research is to enhance the dispatchers' capability to handle flexible situations and produce "good" schedules within current manpower restrictions. In this research, a new scheduling model and …
Nurse Rostering Problems: A Bibliographic Survey, Brenda Cheang, Haibing Li, Andrew Lim, Brian Rodrigues
Nurse Rostering Problems: A Bibliographic Survey, Brenda Cheang, Haibing Li, Andrew Lim, Brian Rodrigues
Research Collection Lee Kong Chian School Of Business
Hospitals need to repeatedly produce duty rosters for its nursing staff. The good scheduling of nurses has impact on the quality of health care, the recruitment of nurses, the development of budgets and other nursing functions. The nurse rostering problem (NRP) has been the subject of much study. This paper presents a brief overview, in the form of a bibliographic survey, of the many models and methodologies available to solve the NRP.
Combining Two Heuristics To Solve A Supply Chain Optimization Problem, Hoong Chuin Lau, Yuyue Song
Combining Two Heuristics To Solve A Supply Chain Optimization Problem, Hoong Chuin Lau, Yuyue Song
Research Collection School Of Computing and Information Systems
In this paper, we consider a real-life supply chain optimization problem concerned with supplying a product from multiple warehouses to multiple geographically dispersed retailers. Each retailer faces a deterministic and period-dependent demand over some finite planning horizon. The demand of each retailer is satisfied by the supply from some predetermined warehouse through a fleet of vehicles which are only available within certain time windows at each period. Our goal is to identify a combined inventory and routing schedule such that the system-wide total cost over the planning horizon is minimised. This problem in essence is an amalgamation of two classical …
A Group Theoretic Tabu Search Methodology For Solving The Theater Distribution Vehicle Routing And Scheduling Problem, John R. Crino
A Group Theoretic Tabu Search Methodology For Solving The Theater Distribution Vehicle Routing And Scheduling Problem, John R. Crino
Theses and Dissertations
The application of Group Theory to Tabu Search is a new and exciting field of research. This dissertation applies and extends some of Colletti's (1999) seminal work in group theory and metaheuristics in order to solve the theater distribution vehicle routing and scheduling problem (TDVRSP). This research produced a robust, efficient, effective and flexible generalized theater distribution model that prescribes the routing and scheduling of multi-modal theater transportation assets to provide economically efficient time definite delivery of cargo to customers. In doing so, advances are provided in the field of group theoretic tabu search and its application to difficult combinatorial …
Phase Transitions In Project Scheduling, Willy Herroelen, Bert De Reyck
Phase Transitions In Project Scheduling, Willy Herroelen, Bert De Reyck
Research Collection Lee Kong Chian School Of Business
Researchers in the area of artificial intelligence have recently shown that many NP-complete problems exhibit phase transitions. Often, problem instances change from being easy to being hard to solve to again being easy to solve when certain of their characteristics are modified. Most often the transitions are sharp, but sometimes they are rather continuous in the order parameters that are characteristic of the system as a whole. To the best of our knowledge, no evidence has been provided so far that similar phase transitions occur in NP-hard scheduling problems. In this paper we report on the existence of phase transitions …
The Scheduling Process In A Depot From The Brazilian Air Force, Fabricio J. Saito
The Scheduling Process In A Depot From The Brazilian Air Force, Fabricio J. Saito
Theses and Dissertations
The Brazilian Air Force (BAF) in its logistic structure contains 5 Air Logistic Centers (depots). This thesis concentrates its analysis on one of the most important BAF depots located at Sao Paulo (PAMASP). This thesis explores the scheduling process currently used in PAMASP. This thesis adopted a managerial approach in a sense that it looked to take a big picture of the current process. The researcher performed field interviews with the goal of describing the process. During the visit to PAMASP, the researcher also gathered problems related to the process. The recommendations stated on this study were based on the …
Crisis Airlift Management: Effective Scheduling, David C. Penny
Crisis Airlift Management: Effective Scheduling, David C. Penny
Theses and Dissertations
This is a report on the basis, data, findings, and models developed for US Transportation Command and Headquarters Air Mobility Command. Focusing on the dynamic scheduling problem that arises during management of airlift assets into space-constrained airfields during a crisis, this research explains the conditions surrounding this event, discusses several areas of potential cross-functional applications, presents analysis of current performance, and provides several modeling possibilities for schedule efficiency. Past research in the Flow Management Problem (an airline flow control issue) is extensive, but specific applications in crisis airlift are long in coming, primarily due to the complexity of the environment. …
Schedule Management Competencies For Department Of Defense Program Managers, Jeffrey F. Brown
Schedule Management Competencies For Department Of Defense Program Managers, Jeffrey F. Brown
Theses and Dissertations
With ongoing public scrutiny of defense system acquisitions, due to numerous program failures resulting from cost and schedule overruns, now, more than ever, cost and schedule-management competencies are critical to program success. This research examined the schedule-management competencies required of defense program managers. A schedule-management competency model was developed from a foundation of past research. The model was evaluated through a mail survey of 484 intermediate and senior level military program managers assigned to Air Force Materiel Command. The results provided by 243 respondents indicate that 25 of the 28 competencies in the model were valuable to program managers and …
Why Schedules Slip: Actual Reasons For Schedule Problems Across Large Air Force System Development Efforts, William M. Cashman
Why Schedules Slip: Actual Reasons For Schedule Problems Across Large Air Force System Development Efforts, William M. Cashman
Theses and Dissertations
The three main objectives of this research were to identify the actual reasons for schedule problems across large Air Force system development efforts, to quantity the importance of each category of reasons in terms of frequency and severity, and to demonstrate that the reasons for schedule problems are not program unique, but are common across system development efforts. To this end, this thesis contains a categorization and analysis of 549 reasons for schedule difficulties on 22 large Air Force Engineering and Manufacturing Development (EMD) programs from 1981 to 1994. These aircraft, missile, aircraft equipment, aircraft upgrade, and simulator programs had …
Automated Manpower Rostering: Techniques And Experience, C. M. Khoong, Hoong Chuin Lau, L. W. Chew
Automated Manpower Rostering: Techniques And Experience, C. M. Khoong, Hoong Chuin Lau, L. W. Chew
Research Collection School Of Computing and Information Systems
We present ROMAN, a comprehensive, generic manpower rostering toolkit that successfully handles a wide spectrum of work policies found in service organizations. We review the use of various techniques and methodologies in the toolkit that contribute to its robustness and efficiency, and relate experience gained in addressing manpower rostering problems in industry.