Sydney C. K. Chu

Generating, scheduling and rostering of shift crew-duties: Applications at the Hong Kong International Airport

Abstract In the context of manpower planning, goal programming (GP) is extremely useful for generating shift duties of fixed length. A fixed-length duty consists of a fixed number of contiguous hours of work in a day, with a meal/rest break somewhere preferably around the middle of these working hours. It is such properties that enable the straightforward, yet flexible GP modeling. We propose GP models for an integrated problem of crew duties assignment, for baggage services section staff at the Hong Kong International Airport. The problem is solved via decomposition into its duties generating phase—a GP planner, followed by its GP scheduling and rostering phase. The results can be adopted as a good crew schedule in the sense that it is both feasible, satisfying various work conditions, and “optimal” in minimizing idle shifts.

A mathematical programming approach towards optimized master production scheduling

The conventional material requirements planning (MRP) and master production scheduling (MPS) systems have gained wide acceptance among production management and control. In this paper, we consider further an aggregate optimization model for the usual MRP/MPS. That is, under a realistic assumption that the availability of material accumulates over time, we seek an optimal production schedule for most profitable operation subject to various capacity constraints. To this end, linear programming formulations are given for various levels of model complexity, ranging from a basic product-mix problem to a global aggregate production planning problem. We examine stage-wise decomposition from the point of view of practical computational feasibility and study the robustness of this decomposition. Finally, simplified numerical results are provided as illustrations.

Hospital lift system simulator: A performance evaluator-predictor

Abstract Hospitals often experience lift congestion as a result of their heavy traffic, complex user types, and relatively slow-moving lifts (due to concerns over safety). Given the increasing number of current and new hospital building blocks that consist of many storeys, a visual simulation-based decision support system (DSS) is recommended. We present the modelling approach and development of a tool capable of being used for lift performance evaluation/prediction of existing/new hospital designs. These are also applicable to other general-purpose lift systems. A new data modelling approach, based on collected empirical traffic data, was developed to estimate the inter-floor passenger traffic. The DSS is flexible enough to allow the input of any zoning policy. The integrated zoning analysis offered here has not been found in existing lift simulators. This paper is the first to model a special feature designed to disable certain lift buttons in order to ensure fair use of the lift service. We carried out field studies of two existing hospitals, and we projected lift demand for a new hospital under construction. Performances at all three hospitals with different design structures under different operational control policies and lift features are given.

A Heuristic Algorithm for the Inner-City Multi-Drop: Container Loading Problem

Economic globalization, increasing fuel cost, and environmental problems provide a strong stimulation for inner-city container carriers to utilize container space more efficiently in transporting goods for multiple clients during a single round trip. A wall-building heuristic algorithm based on the binary tree data structure is proposed to solve the container loading problem with multi-drop constraints. A dynamic space decomposition approach, together with a repacking and space amalgamation strategy, permits an efficient and effective loading plan to pack containers, illustrated by numerical experiments.

Maximum Resolution Topology for Online Auction Markets

A topological model of an online auction market is a simultaneous graphical display of all the dimensions of its relevant database, providing a geometrical shape as a visually descriptive statistics of the market at any particular instance of its development. In particular, various dimensions were identified for constructing a multi-attribute dichotomy that can help discern relative advantages to buyers and sellers, using only available, operational data, and without expert knowledge of the items involved or the prices attained. With a reference subset of prejudged cases, the configuration of the dimensions and the angles among them can be optimized for a topology that maximizes the resolution of such dichotomies. The approach is illustrated in a global comparative study of four markets in five countries. It can be a useful tool for data mining and visualization in the design, study, and analysis of online auction markets.

Nurses allocation models for maternal and child health services

Maternal and Child Health (MCH) centres in Hong Kong offer, for children aged below six and women of childbearing age, a comprehensive range of health services regularly performed by nurses of different ranks. While each rank has its specific duties, nurses of a higher rank can step down to the work of a more junior rank when necessary. However, cross-regional deployments of nurses occur less frequently. We develop goal programming models of ‘optimal’ MCH nurses allocation. The presence and absence of nurses’ ‘cross-over’ of work functions are explicitly considered. The results show that more equitable manpower levelling can be achieved, with flexibility (in the longer term) on cross-regional deployment of nurses as a possible way of operational improvement when the entire MCH service is taken as a whole.

Order batching and picking in a synchronized zone order picking system

Order picking has been considered as one of the most critical operations in warehouse. In this study, we propose an analytical approximation model based on probability and queueing network theory to analyze order batching and picking area zoning on the mean order throughput time in a synchronized zone picker-to-part order picking system. The resulting model can be easily applied in the design and selection process of order picking systems.

Data and GP modeling framework for manpower planning: The case of fixed-length duties

In the context of manpower planning in general, and with respect to fixed-length shift-duties in particular, Goal Programming (GP) is often useful as an optimization modeling technique for generating shift-duties of worker schedules. A (regular-time) fixed-length duty consists of a fixed number of contiguous hours of work in a day, with a meal/rest break somewhere preferably around the middle of these working hours. It is such properties that enable the straightforward, yet flexible modeling and computation. Such an optimization modeling is built upon the essential foundation of a detailed data modeling and its analysis for all the driving parameters and demand/supply input necessary for numerical computations. Hence data model and GP model form two integral components of this project. Results reported here illustrate the case of baggage service agents planning at the Hong Kong International Airport. Finally, implementation as DSS is briefly described.

Planning and Scheduling Staff Duties by Goal Programming

We propose goal programming (GP) models for an integrated problem of staff duties planning and scheduling, for baggage services section staff at the Hong Kong International Airport. The problem is solved via its decomposition into a GP planner, followed by a GP scheduler. The results can be adopted as a good crew schedule in the sense that it is both feasible, satisfying various work conditions, and “optimal” in minimizing overtime shifts.

Goal Programming Models and DSS for Manpower Planning of Airport Baggage Service

Goal Programming (GP) models and Decision Support System (DSS) are two powerful tools dealing with manpower planning problems, not only on research level, but also as practical tools for industrial implementation. Goal programming is often useful as an optimization modeling technique for generating shift-duties of worker schedules. In our project for the baggage service agency at the Hong Kong International Airport, we proposed three model formulations based on the basic fixed-length shift duties generation model to approach various combinations of goals of manpower planning. Such an optimization modeling is built upon the essential foundation of a detailed data modeling and its analysis for all the driving parameters and demand/supply input necessary for numerical computations. The data model and GP model thus form the two integral components of the overall automation system – the DSS, which is an automatic computer based and user-friendly system to support management on planning decisions.