An Interactive Planning Model for the New Zealand Dairy Industry

A long-term planning model for a large New Zealand dairy company is described. The model presents an integrated view of the company's operation, including transportation and processing. The model used is based on a network formulation, NETPLAN, developed by the authors to carry out the optimisation. NETPLAN is highly flexible, interactive and provides graphical output of the results. The optimisation maximises net revenue based on product prices, variable process costs and variable transport costs subject to factory capacity, product demand and raw material supply constraints.     

An Interactive Aid to Financial Planning

The problem of producing financial plans for the subsidiary of a multinational corporation is one which is critical, especially in uncertain times. In addition there is always a pressing time constraint. This paper describes a suite of models which are in use by Caltex Oil South Africa to assist in this area. The approach adopted was to provide simple models which work interactively. The financial planning analysts were able to be very involved in the project because a high level modelling language was used which they could easily comprehend. The tremendous benefits of this type of approach in terms of user acceptance and in other areas are examined.     

Production Planning in the New Zealand Dairy Industry

From 1977 onwards, D.S.I.R. has been developing an L.P. model to help the largest N.Z. dairy company plan its medium-term production. This time-staged model finds the most profitable daily production schedule of the various powder, casein, cheese and butter products. Computer reports and graphics show Company management how to allocate the milk available in the various farming regions to the Company's factories, and where to send the by-products for further processing.The L.P. models seasonal fluctuations in wholemilk availability and quality, as well as transport costs, factory capacities and costs, and product-yields and prices. Comparison runs have shown that the L.P. increases the profitability of the manual plan by over $5000 per day (because the computer can handle changing yields, factory costs and by-product processing). The model gives management the ability to adjust production plans quickly in response to improved information, new market opportunities and emergencies like plant breakdown.     

An Interactive Algorithm for Multi-objective Route Planning

We address the route selection problem for Unmanned Air Vehicles (UAV) under multiple objectives. We consider a general case for this problem, where the UAV has to visit several targets and return to the base. We model this problem as a combination of two combinatorial problems. First, the path to be followed between each pair of targets should be determined. We model this as a multi-objective shortest path problem. Additionally, we need to determine the order of the targets to be visited. We model this as a multi-objective traveling salesperson problem (MOTSP). The overall problem is a combination of these two problems, which we define as a generalized MOTSP. We develop an exact interactive approach to identify the best paths and the best tour of a decision maker under a linear utility function.     

A Production Planning and Stock Control Problem in the Textile Industry

This paper describes the techniques used in an enquiry into production planning and stock holding problems encountered by one of our member firms.The investigation of the problem falls into three parts:

1. i)
   The analysis of demand.
    
2. ii)
   The determination of optimum stock levels.
    
3. iii)
   The solution of the allocation problem which arises if the capacity available for the production of stock lines is not equal to the amount required to bring stocks back to the optimum levels. This problem has not been fully investigated, but a proposed method of solution is given in an appendix.
    

     

Production Planning and Inventory Control on a Chemical Plant

In this paper formulae are derived to give the optimum run lengths on a plant producing two products alternately. The general case of n runs of one product to one run of the other is considered. The work is applied to a chemical plant and the difficulties of determining certain costs are discussed. It is estimated that appreciable savings can be made.An empirical method of calculating buffer stocks is then described, together with a method of planning production before an annual shut-down. This part of the work does not lead to any substantial savings in cost, but reduces the danger of running out of stock.     

枚举法在制定生产计划中的应用

赵学慧，赵瑛．枚举法在制定生产计划中的应用，数理统计与管理，１９９７，１６（１），１６～１８．本文通过用枚举法制定生产计划的实例，向管理人员介绍计算线性规划最优解的一种简单而易行的方法     

An Analogue Equipment for Use in Production Planning

Many planning problems may be more efficiently resolved by an interaction of man and machine than by either alone. This paper considers an analogue equipment built to assist the production planning of a small number of products which share common labour and machine resources. It deals with up to four products and six production periods at a time. The stock levels which would result at the end of each period with a given forecast demand pattern and a given labour pattern are shown on an array of current meters. This rapid display of the stock position enables the operator to assess many more production plans in a given time than previous manual methods could allow. It also permits rapid modifications to be made to a plan with knowledge of the likely consequences. This is a simple and effective approach to a problem which is difficult to treat analytically.     

An Interactive Dynamic Inventory-Production Control System

The development and evaluation of an interactive model for controlling inventories and scheduling production in a high technology batch production environment are discussed. The model allows the use of expert knowledge and company policy for matters such as customer service and safety stocks, in an interactive way. Production of a large number of products has to be scheduled for a number of time periods and a modified Wagner-Whitin algorithm is used for developing good schedules. A versatile data and information management system is a part of the developed software which has been implemented using a standard microcomputer. An evaluation suggests that the system is a practical one for use by busy managers. Further, it results in substantial cost savings and increased customer service.     

Linear Programming Applied to Production Planning and Operation of a Chemical Process

To employ linear programming in production-planning problems in the chemical industry it is often necessary to make a linear model of plant which seems highly non-linear. An approach with some generality is described that reasonably combines accuracy and economy.Next, the hierarchy of planning levels around a chemical plant is considered from investment planning through to process operation. This highlights difficulties, inherent in on-line computer optimizing proposals, that are often played down. In short, the considerations which have most influence on determining optimum operating conditions are shown to have little to do with the instantaneous state of the chemical process.Given that perfection is unattainable it is argued that in some cases the best way to run chemical plant is infrequent off-line optimization leading to plans whose feasibility is maintained in the short term with very little calculation if the right sort of linear process model exists.     

Fuzzy Multi-fractional Programming for Land Use Planning in Agricultural Production System

In this paper, we present a multi-objective linear fractional programming (MOLFP) approach for multi-objective linear fuzzy goal programming (MOLFGP) problem. Here, we consider a problem in which a set of pair of goals are optimized in ratio rather than optimizing them individually. In particular, we consider the optimization of profit to cash expenditure and crop production in various seasons to land utilization as a fractional objectives and used remaining goals in its original form. Further, the goals set in agricultural production planning are conflicting in nature; thus we use the concept of conflict and nonconflict between goals for computation of appropriate aspiration level. The method is illustrated on a problem of agricultural production system for comparison with Biswas and Pal [1] method to show its suitability.     

Logistics Planning in the Downstream Oil Industry

Strategic logistics chain planning is of great importance within the downstream oil industry. Logistics networks originate at refineries and terminate at the final delivery point — the customer. Types of bulk transportation used and the main product classes are described. The business decisions which need to be addressed are stated. A corresponding model is formulated partly in mathematical and partly in qualitative terms. The cost of road vehicle delivery to customers is modelled. The business risks associated with changes to the logistics infrastructure are indicated.     

The Colliery Planning System—A Microcomputer-based Aid to Colliery (Production) Planning

The Colliery Planning System (C.P.S.) is a medium- to long-term planning aid written in APL and running on a Superbrain microcomputer. It was developed by and has been used extensively within the Operational Research Executive (O.R.E.) of the National Coal Board and has been in routine use by planning staff in one of the N.C.B.'s Areas for over two years. This paper discusses the Colliery Planning System and outlines the problems it has been necessary to overcome to achieve implementation.     

An Interactive Simulation in the Health Service

There is an unmet demand for the treatment of irreversible kidney failure, particularly in the older age groups. A model of the treatment system was built to explore the implications of meeting the demand, giving different priorities to the available treatments and changing the balance between home and hospital. This discrete event simulation, developed in the Wessex Region, describes the system realistically, including resource use and constraints, the arrival of kidneys for transplantation and the matching of donors with recipients. It is written in Pascal on an Apple II computer and uses shadow entities to describe the survival of patients on each type of treatment. The model was validated with techniques which included the use of a tabular display while the simulation was running. The model has proved to be easy to use and robust both to different data requirements and extreme policy changes. The techniques developed have more general application in the Health Service context.     

An Interactive Stock Control System with a Strategic Management Role

This note describes the design, implementation and consequences of a stock control system employing interactive mini computers for a number of builders and plumbers merchants.The system enables the quantification of the strategic decisions of the company, for example the consequences of changing the total investment in stock, or the overall service level. The selected strategy determines the calculations used for the interactive buying routines, which consider items in groups. Other aspects and the results of the implementation are described together with the necessary theory and routines employed.     

Optimal Production Planning in a Stochastic Manufacturing System with Long-Run Average Cost

This paper is concerned with the optimal production planning in a dynamic stochastic manufacturing system consisting of a single machine that is failure prone and facing a constant demand. The objective is to choose the rate of production over time in order to minimize the long-run average cost of production and surplus. The analysis proceeds with a study of the corresponding problem with a discounted cost. It is shown using the vanishing discount approach that the Hamilton–Jacobi–Bellman equation for the average cost problem has a solution giving rise to the minimal average cost and the so-called potential function. The result helps in establishing a verification theorem. Finally, the optimal control policy is specified in terms of the potential function.     

Optimal Production and Marketing Planning

This paper presents an integrated production, marketing and inventory model which determines the production lot size, marketing expenditure and products selling price. Our model is highly nonlinear and non-convex and cannot be solved directly. Therefore, Geometric Programming (GP) is used to locate the optimal solution of the proposed model. In our GP implementation, we use a transformed dual problem in order to reduce the model to an optimization of an unconstrained problem in a single variable and the resulting problem is solved using a simple line search. We analyze the solution in different cases in order to study the behaviour of the model and for each case, a numerical example is used to demonstrate the implementation of our analysis.     

An Exact Solution Algorithm for a Class of Production Planning and Scheduling Problems

This paper presents a formulation and an exact solution algorithm for a class of production planning and scheduling problems. The problem is one of optimally specifying production levels for each product in each period of the planning horizon. The objective is to minimize the sum of the set-up, regular time production, overtime and inventory holding costs. The problem has been formulated as a variation of fixed charge transportation problem. The problem discussed here is NP-hard in computational complexity. A numerical example is presented for better understanding of the algorithm.