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1.
Inspired by a case study from industry, the production of special chemical products is considered. In this industrial environment,
multi-purpose equipment is operated in batch mode to carry out the diverse processing tasks. Often, extensive set-up and cleaning
of the equipment are required when production switches between different types of products. Hence, processes are scheduled
in campaign mode, i.e. a number of batches of the same type are processed in sequence. The production of chem ical products
usually involves various stages with significant cumulative lead times. Typically, these production stages are assigned to
different plants. A hierarchical modelling approach is presented which co-ordinates the various plant operations within the
entire supply network. In the first stage, the length of the campaigns, their timing, the corresponding material flows, and
equipment requirements have to be determined. At this stage, an aggregation scheme based on feasibility constraints is employed
in order to reflect the limited availability of the various types of production equipment. The second stage consists of an
assignment model, which allocates the available equipment units between the production campaigns determined in the first stage
of the solution procedure. In the third stage, resource conflicts are resolved, which may occur if clean-out operations and
minimal campaign lengths have to be considered. The proposed hierarchical approach allows a more compact model formulation
compared to ot her approaches known from the literature. As a result, a very efficient and flexible solution approach is obtained.
In particular, commercially available standard solvers can be used to solve a wide range of campaign planning problems arising
in the chemical industry. 相似文献
2.
Guido Berning Marcus Brandenburg Korhan Gürsoy Vipul Mehta Franz-Josef Tölle 《OR Spectrum》2002,24(4):371-401
This paper considers a complex scheduling problem in the chemical process industry involving batch production. The application
described comprises a network of production plants with interdependent production schedules, multi-stage production at multi-purpose
facilities, and chain production. The paper addresses three distinct aspects: (i) a scheduling solution obtained from a genetic algorithm based optimizer, (ii) a mechanism for collaborative planning among the involved plants, and (iii) a tool for manual updates and schedule changes. The tailor made optimization algorithm simultaneously considers alternative
production paths and facility selection as well as product and resource specific parameters such as batch sizes, and setup
and cleanup times. The collaborative planning concept allows all the plants to work simultaneously as partners in a supply
chain resulting in higher transparency, greater flexibility, and reduced response time as a whole. The user interface supports
monitoring production schedules graphically and provides custom-built utilities for manual changes to the production schedule,
investigation of various what-if scenarios, and marketing queries.
RID="*"
ID="*" The authors would like to thank Hans-Otto Günther and Roland Heilmann for helpful comments on draft versions of this
paper. 相似文献
3.
Josef Kallrath 《OR Spectrum》2002,24(3):315-341
We describe and solve a real world problem in chemical industry which combines operational planning with strategic aspects.
In our simultaneous strategic & operational planning (SSDOP) approach we develop a model based on mixed-integer linear (MILP)
optimization and apply it to a real-world problem; the approach seems to be applicable in many other situations provided that
people in production planning, process development, strategic and financial planning departments cooperate.
The problem is related to the supply chain management of a multi-site production network in which production units are subject
to purchase, opening or shut-down decisions leading to an MILP model based on a time-indexed formulation. Besides the framework
of the SSDOP approach and consistent net present value calculations, this model includes two additional special and original
features: a detailed nonlinear price structure for the raw material purchase model, and a detailed discussion of transport
times with respect to the time discretization scheme involving a probability concept. In a maximizing net profit scenario
the client reports cost saving of several millions US$.
The strategic feature present in the model is analyzed in a consistent framework based on the operational planning model,
and vice versa. The demand driven operational planning part links consistently to and influences the strategic. Since the
results (strategic desicions or designs) have consequences for many years, and depend on demand forecast, raw material availability,
and expected costs or sales prices, resp., a careful sensitivity analysis is necessary showing how stable the decisions might
be wit h respect to these input data. 相似文献
4.
Many fast moving consumers good manufacturing companies produce a moderate number of intermediates that are combined in many
different ways to generate an enormous variety of end products. To do that, such companies usually run continuous production
plants in a make-to-stock environment. The process structure includes a fabrication area yielding basic intermediates that
are stocked in a large middle storage space, and a packing sector where finished products usually comprising several intermediates
are manufactured. Intermediates all undergo the same sequence of processing stages and the production of any campaign is sequentially
allocated to an ordered set of end products. An MILP continuous time scheduling problem formulation handling independently
assignment and sequencing decisions and considering sequence-dependent setup times and specific due dates for export orders
has been developed. The problem objective is to meet all end-product demands at minimum make-span. The proposed model is able
to account for assorted products, multiple campaigns for a particular intermediate even at the same unit and the consecutive
allocation of an intermediate campaign to different finished products. Moreover, it can easily embed powerful preordering
rules to yielding reduced MILP formulations so as to tackle real-world industrial problems at low computational cost. The
approach has been successfully applied to large-scale industrial examples.
RID="*"
ID="*" The authors acknowledge financial support from FONCYT under Grant 14-07004, and from “Universidad Nacional del Litoral”
under CAI+D 121.
Correspondence to: J. Cerdá 相似文献
5.
6.
In order to assess the economic and ecological effects of inter-company energy supply concepts, an optimising model integrating
investment and long-term production planning has been developed. The model represents the energy production of companies on
a very disaggregated level taking into account different resources, energy carriers and production processes. This model has
been applied to five industrial companies to analyse the economic and ecological implications resulting from investments in
inter-company energy supply concepts. Existing technologies as well as possible investment options have been assessed by a
techno-economic analysis taking into account company specific circumstances. In addition, the new German combined heat and
power law has been modelled in detail, because the supplementary payments legally established in this law may effect energy
go supply concepts in a considerable way. Computational results show the installation of a combined cycle power plant adapted
to the specific conditions of the case at hand would be the most promising option to fulfil the future energy demand of the
companies involved.
Correspondence to: W. Fichtner 相似文献
7.
An Advanced Planning System (APS) offers support at all planning levels along the supply chain while observing limited resources.
We consider an APS for process industries (e.g. chemical and pharmaceutical industries) consisting of the modules network
design (for long–term decisions), supply network planning (for medium–term decisions), and detailed production scheduling
(for short–term decisions). For each module, we outline the decision problem, discuss the specifi cs of process industries,
and review state–of–the–art solution approaches. For the module detailed production scheduling, a new solution approach is
proposed in the case of batch production, which can solve much larger practical problems than the methods known thus far.
The new approach decomposes detailed production scheduling for batch production into batching and batch scheduling. The batching
problem converts the primary requirements for products into individual batches, where the work load is to be minimized. We
formulate the batching problem as a nonlinear mixed–integer program and transform it into a linear mixed–binary program of
moderate size, which can be solved by standard software. The batch scheduling problem allocates the batches to scarce resources
such as processing units, workers, and intermediate storage facilities, where some regular objective function like the makespan
is to be minimized. The batch scheduling problem is modelled as a resource–constrained project scheduling problem, which can
be solved by an efficient truncated branch–and–bound algorithm developed recently. The performance of the new solution procedures
for batching and batch scheduling is demonstrated by solving several instances of a case study from process industries. 相似文献
8.
Integrated planning of acquisition,disassembly and bulk recycling: a case study on electronic scrap recovery 总被引:7,自引:0,他引:7
Abstract. Due to national and supranational legislation activities, the recovery of discarded products will attain an increasing momentum.
Electronic equipment consists of many different parts and materials. Therefore, the related recovery process is often divided
into disassembly to remove harmful substances or reusable parts and into bulk recycling to recover ferrous and non-ferrous
metals. In order to consider the interactions between choice of scrap to be recovered (acquisition problem), disassembly and
bulk recycling, a mixed-integer linear programming model for integrated planning of these stages is presented in this case
study. It is applied to determine the daily allocation of products to processes for a major electronic scrap recovery centre
that faces limited processing capacities and market restrictions. The optimization calculations covering typical discarded
electronic products to be recycled in the related centre lead to a relevant improvement of the economic success.
RID="*"
ID="*" The authors would like to thank the German “Bundesministerium für Bildung und Forschung” (Federal Ministry of Education
and Research) for supporting the research project “Substance Flow Oriented Closed Loop Supply Chain Management in the Electrical
and Electronic Equipment Industry (STREAM)rdquo;.
Correspondence to: T. Spengler 相似文献
9.
Francisca H.E. Wouda Paul van Beek Jack G.A. J. van der Vorst Heiko Tacke 《OR Spectrum》2002,24(4):449-465
Between 1995 and 1998 Nutricia acquired a number of dairy companies in Hungary. Each of these companies produced a wide variety
of products for its regional market. Although alterations had been made to the production system in the last few years, production
and transportation costs were still substantial. This paper presents a research study with regard to the optimisation of the
supply network of Nutricia Hungary using a mixed-integer linear programming model. Focussing on consolidation and product
specialisation of plants the objective was to find the optimal number of plants, their locations and the allocation of the
product portfolio to these plants, when minimizing the sum of production and transportation costs. The model is in line with
traditional location/allocation models, with a modification concerning inter-transportation of semi-finished products between
plants. The production costs used in this model are based on a Green field situation, taking into account new and more advanced
technologies available today. The model is used by the Nutricia Dairy and Drinks Group as a decision supporting tool.
Correspondence to: F. H. E. Wouda 相似文献
10.
Modern chemical production is customer-driven and the desired delivery time for the products is often shorter than their
campaign length. In addition, the raw materials supplying time is often long. These features make it desirable to provide
tools to support collaborative supply chain decision making, preferably over the Internet, and where there are conflicts,
compromise decisions can be quickly reached and the effects of the decisions can be quantitatively simulated. This paper des
cribes such a multi-agent system (MAS) that can be used to simulate the dynamic behaviour and support the management of chemical
supply chains over the Internet. Geographically distributed retailers, logistics, warehouses, plants and raw material suppliers
are modelled as an open and re-configurable network of co-operative agents, each performing one or more supply chain functions.
Communication between agents is made through the common agent communication language KQML (knowledge query message language).
A t the simulation layer, the MAS allows distributed simulation of the chain behaviour dynamically, so that compromise decisions
can be rapidly and quantitatively evaluated. Because in a chemical supply chain the scheduling of the plant often dominates
the chain performance, an optimum scheduling system for batch plants is integrated into the MAS. The functions of the system
are illustrated by reference to a case study for the supply and manufacture using a multi-purpose batch plant of paints and
coatings. 相似文献
11.
Design is described as creative design problem solving. The first step of the design process is to identify and analyze the
design problem. This step has an important influence on the creation of an effective design solution. In two experiments,
we tested the benefits that sketching provides during the analysis process in design problem solving. In particular, this
paper focuses on the design process, the act of sketching, the sketch itself, and the final product. In prior studies, the
process of sketching has been shown to enhance the construction of a mental representation, and thus the sketch has improved
the analysis of the problem. The memory supporting effect of sketches is verified in the second experiment discussed in this
paper. Finally, this paper also discusses the support possibilities the sketch offers for the early stages of the design process. 相似文献
12.
Planning and scheduling in the process industry 总被引:15,自引:0,他引:15
Josef Kallrath 《OR Spectrum》2002,24(3):219-250
Since there has been tremendous progress in planning and scheduling in the process industry during the last 20 years, it
might be worthwhile to give an overview of the current state-of-the-art of planning and scheduling problems in the chemical
process industry. This is the purpose of the current review which has the following structure: we start with some conceptional
thoughts and some comments on special features of planning and scheduling problems in the process industry. In Section 2 the
focus is on planning problems while in Section 3 different types of scheduling problems are discussed. Section 4 presents
some solution approaches especially those applied to a benchmark problem which has received considerable interest during the
last years. Section 5 allows a short view into the future of planning and scheduling. In the appendix we describe the Westenberger-Kallrath
problem which has already been used extensively as a benchmark problem for planning and scheduling in the process industr
y. 相似文献
13.
We have developed a taxonomy that classifies those needs of a corporation that impact product design. We call these needs
corporate requirements. In contrast to the consumer or end-user requirements, corporate requirements come from internal sources
such as marketing, finance, manufacturing, and service. This taxonomy allows for an organized method of gathering, managing,
and retrieving the requirements. The taxonomy also helps to facilitate a broader, clearer form of Quality Function Deployment.
Generic in nature, this taxonomy provides a template with which to create taxonomies for a given product within a given company
or industry. We include an industrial case study to demonstrate this concept. 相似文献
14.
The paper deals with batch scheduling problems in process industries where final products arise from several successive chemical
or physical transformations of raw materials using multi–purpose equipment. In batch production mode, the total requirements
of intermediate and final products are partitioned into batches. The production start of a batch at a given level requires
the availability of all input products. We consider the problem of scheduling the production of given batches such that the
makespan is minimized. Constraints like minimum and maximum time lags between successive production levels, sequence–dependent
facility setup times, finite intermediate storages, production breaks, and time–varying manpower contribute to the complexity
of this problem. We propose a new solution approach using models and methods of resource–constrained project scheduling, which
(approximately) solves problems of industrial size within a reasonable amount of time.
Received: October 15, 1999 / Accepted: March 21, 2000 相似文献
15.
We consider a single-stage single-product production system. Produced units may be non-defective, reworkable defective, or
non-reworkable defective. The system switches between production and rework. After producing a fixed number (N) of units, all reworkable defective units are reworked. Reworkable defectives are perishable or can become technologically
obsolete. We assume that the rework time and the rework cost increase linearly with the time that a unit is held in stock.
Therefore, N should not be too large. On the other hand, N should not be too small either, since there are set-up times and costs associated with switching between production and rework.
For a given N, we derive an explicit expression for the average profit (sales revenue minus costs). Using this expression, the optimal
value for N can be determined numerically. Moreover, it is easy to perform a sensitivity analysis, as we illustrate.
RID="*"
ID="*"The research of Dr. Ruud H. Teunter has been made possible by a fellowship of the Royal Netherlands Academy of Arts
and Sciences. The research presented in this paper is part of the research on re-use in the context of the EU sponsored TMR
project REVersed LOGistics (ERB 4061 PL 97-5650) in which take part the Otto-von-Guericke Universitaet Magdeburg (D), the
Erasmus University Rotterdam (NL), the Eindhoven University of Technology (NL), INSEAD (F), the Aristoteles University of
Thessaloniki (GR), and the University of Piraeus (GR). We thank the anonymous referees for their many helpful comments.
Correspondence to: R. H. Teunter 相似文献
16.
Current market conditions require design and manufacturing companies to continually increase product functionality, reduce
design cycles, decrease cost and improve quality. One way to improve quality is to minimize the impact part and process variation
has on final product quality. Although companies know they must reduce variation, they are still struggling with executing
coherent variation management strategies. To understand why companies still fail to systematically address variation, an ideal
model of variation management is proposed, entitled Variation Risk Management (VRM). This model was used to assess the state of industry practice. These results are compared to the current literature
available on the subject. It was found that many problems with industry implementation are due to a lack of quantitative models
that enable a design team to make quick and accurate decisions. This paper concludes with a list of interesting challenges
facing the VRM field. 相似文献
17.
A Mathematical Framework for the Key Characteristic Process 总被引:3,自引:0,他引:3
Anna C. Thornton 《Research in Engineering Design》1999,11(3):145-157
To maximize product quality, a product design team selects concepts and dimensions to minimize a product’s sensitivity to
variation. However, even for the most robust products, it is rarely possible to transition a product into production without
encountering any variation-related problems. In a complex product, it is not economically or logistically feasible to control
and/or monitor the thousands of tolerances specified in a product’s drawing set. To address this problem, many organizations
are using Key Characteristic (KCs) methods to identify where excess variation will most significantly affect product quality,
and what product features and tolerances require special attention from manufacturing. As simple as this principle seems,
most companies struggle to effectively implement KC methods because no quantitative methods to prioritize KCs exist. This
paper develops a mathematical definition of a KC based on a variation propagation model. In addition, it develops a quantitative
effectiveness measure used to prioritize where verification, variation reduction, and on-going monitoring should be applied.
The effectiveness measure incorporates the cost of control, the benefit of control, and the expected change in process capability.
The methods are illustrated using an automotive door assembly. 相似文献
18.
Improving Systems by Combining Axiomatic Design, Quality Control Tools and Designed Experiments 总被引:2,自引:0,他引:2
Fredrik Engelhardt 《Research in Engineering Design》2000,12(4):204-219
This paper presents an approach for solving design problems in existing designs. A design analysis with Axiomatic Design,
called Design Object Analysis, describes a product or a system in terms of Customer Needs (CNs), Functional Requirements (FRs),
Design Parameters (DPs) and Process Variables (PVs), as well as their associated Design Matrices (DMs). In this paper, the
design analysis is combined with a thorough investigation of possible problems within the design, utilizing the seven quality
tools, noise factor analysis, and designed experiments to form an approach for quality improvements and problem solving. The
Design Object Analysis helps secure valid input-factors to the designed experiments, and the designed experiments correct
or improve the assumptions made in the Design Object Analysis. Thus, a combination of product modeling by Axiomatic Design
and designed experiments overcomes shortcomings of the two methods. The benefits of performing a Design Object Analysis, as
compared to other methods, become clear when it comes to evaluating the results from the designed experiment, and preventing the problem. Once the critical parameters are confirmed, and the design matrices are updated, suggested design improvements
can then be checked against the design matrices, and the system effect of a design-change-order can be estimated. The approach
described in this paper was successfully applied and verified in a case study at a large automotive company. 相似文献
19.
Critical design decisions are commonly made throughout the product development process assuming known material and process
behavior. However, stochastic variation during manufacture can inadvertently result in inferior or unacceptable product performance
and reduced production yields. Stochastic simulations have been developed to estimate the end-use performance distribution
prior to the commitment of hard tooling. This article proposes a definition for integrated product and process robustness,
and extends existing stochastic methods to model the important role of the manufacturing flexibility in elimination of defects
and product optimization. The goal is to enable the designer to understand and account for not only the negative effects of
manufacturing variation, but also the positive impact of manufacturing flexibility wherein instantaneous corrections in the
manufacturing process can frequently improve the product quality and eliminate flaws in the product design. Then, a methodology
is introduced and contrasted with conventional development methods in the evaluation of best practices for development of
a molded plastic component. 相似文献
20.
A scheduling method for Berth and Quay cranes 总被引:12,自引:2,他引:10
This paper discusses a method for scheduling Berth and Quay cranes, which are critical resources in port container terminals.
An integer programming model is formulated by considering various practical constraints. A two-phase solution procedure is
suggested for solving the mathematical model. The first phase determines the Berthing position and time of each vessel as
well as the number of cranes assigned to each vessel at each time segment. The subgradient optimization technique is applied
to obtain a near-optimal solution of the first phase. In the second phase, a detailed schedule for each Quay crane is constructed
based on the solution found from the first phase. The dynamic programming technique is applied to solve the problem of the
second phase. A numerical experiment was conducted to test the performance of the suggested algorithms.
RID="*"
ID="*" This research has been supported in part by Brain Korea 21 Program (1999–2002).
Correspondence to: Y.-M. Park 相似文献