共查询到20条相似文献,搜索用时 31 毫秒
1.
Plant co-ordination in pharmaceutics supply networks 总被引:3,自引:0,他引:3
The production of active ingredients in the chemical-pharmaceutical industry involves numerous production stages with cumulative
lead times of up to two years. Mainly because of rigorous purity requirements and the need of extensive cleaning of the equipment
units, production is carried out in campaigns, i.e. multiple batches of the same product type are produced successively before
changing to another product type. Each campaign requires a specific configuration of equipment units according to the recipes
of the particular chemical process. In the chemical-pharmaceutical industry, production stages are often assigned to different
locations, even different countries. Hence the co-ordination of plant operations within the resulting multi-national supply
network is of major importance. A key issue is the co-ordination of campaign schedules at different production stages in the
various plants. In practice, it is almost impossible to determine exact optimal solutions to the corresponding complex supply
network problem with respect to overall logistics costs. In order to reduce the required computational effort, we introduce
several aggregation schemes and a novel MILP model formulation which is based on a continuous representation of time. Moreover,
we propose an iterative near-optimal solution procedure which can be successfully applied to even exceptionally large real
life problem instances. The applicability of the approach suggested is shown using a case study from industry.
Correspondence to: H.-O. Günther 相似文献
2.
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
3.
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
4.
5.
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
6.
Supply chain management in chemical process industry focuses on production planning and scheduling to reduce production cost
and inventories and simultaneously increase the utilization of production capacities and the service level. These objectives
and the specific characteristics of chemical production processes result in complex planning problems. To handle this complexity,
advanced planning systems (APS) are implemented and often enhanced by tailor-made optimization algorithms. In this article,
we focus on a real-world problem of production planning arising from a specialty chemicals plant. Formulations for finished
products comprise several production and refinement processes which result in all types of material flows. Most processes
cannot be operated on only one multi-purpose facility, but on a choice of different facilities. Due to sequence dependencies,
several batches of identical processes are grouped together to form production campaigns. We describe a method for multicriteria
optimization of short- and mid-term production campaign scheduling which is based on a time-continuous MILP formulation. In
a preparatory step, deterministic algorithms calculate the structures of the formulations and solve the bills of material
for each primary demand. The facility selection for each production campaign is done in a first MILP step. Optimized campaign
scheduling is performed in a second step, which again is based on MILP. We show how this method can be successfully adapted
to compute optimized schedules even for problem examples of real-world size, and we furthermore outline implementation issues
including integration with an APS. 相似文献
7.
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
8.
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
9.
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
10.
Most production planning and control (PPC) systems used in practice have an essential weakness in that they do not support hierarchical planning with feedback and do not observe resource constraints at all production levels. Also, PPC systems often do not deal with particular types of production, for example, low-volume production. We propose a capacity-oriented hierarchical approach to single-item and small-batch-production planning for make-to-order production. In particular, the planning stages of capacitated master production scheduling, multi-level lot sizing, temporal and capacity planning, and shop floor scheduling are discussed, where the degree of aggregation of products and resources decreases from stage to stage. It turns out that the optimization problems arising at most stages can be modelled as resourceconstrained project scheduling problems. 相似文献
11.
Risk hedging via options contracts for physical delivery 总被引:6,自引:2,他引:6
We develop an analytical framework for the valuation of options contracts for physical delivery that enable risk-sharing
between the trading partners. The spot market price risk, the buyer's demand risk and the seller's marginal cost risk, which
are key to many industrial settings such as the chemical industry, are explicitly incorporated. Analytical expressions for
the buyer's optimal reservation quantity and the seller's optimal tariff are derived and related to the risk management needs
in the industry. The ensuing discussion shows how contingency contracts for physical delivery can complement financial derivative
instruments within a company's risk management approach. 相似文献
12.
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
13.
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
14.
Roland Heilmann 《OR Spectrum》2001,23(3):335-357
This paper presents a heuristic solution procedure for a very general resource–constrained project scheduling problem. Here,
multiple execution modes are available for the individual activities of the project. In addition, minimum as well as maximum
time lags between different activities may be given. The objective is to determine a mode and a start time for each activity
such that the temporal and resource constraints are met and the project duration is minimized. Project scheduling problems
of this type occur e.g. in process industries. The heuristic is a multi–pass priority–rule method with backplanning which
is based on an integration approach and embedded in random sampling. Its performance is evaluated within an experimental performance
analysis for problem instances of real–life size with 100 activities and up to 5 modes per activity.
Received: September 22, 2000 / Accepted: May 18, 2001 相似文献
Received: September 22, 2000 / Accepted: May 18, 2001 相似文献
15.
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
16.
Knut Alicke 《OR Spectrum》2002,24(1):1-18
The convergence of European states can be expected to lead to an increase in the trading of goods within the next few years
and thus to a growing demand for transport. Overland intermodal transport is an important development, because it combines
the advantages of rail for long distance transportation with the effective area cover offered by road. Different terminal
concepts and production forms have been developed to increase the flexibility of intermodal transport and to make it more
attractive for the customer.
The intermodal terminal concept investigated in this paper is called Mega Hub. The configuration and the control of the terminal
is a complex and challenging task. Here, the terminal is modeled as a multi-stage transshipment problem. In this approach,
sequence-dependent duration of empty moves, alternative assignments (of containers to cranes) and a sequence-dependent number
of operations have to be handled. An optimization model based on Constraint Satisfaction is formulated and heuristics for
the search procedure, especially value and variable ordering are developed.
Received: May 2, 2000 / Accepted: July 4, 2001 相似文献
17.
In this paper, related product functions are determined for a group of approximately 70 consumer products. Using customer
need data, a new matrix approach is introduced to identify these relationships. Techniques are then created for determining
product similarity. These techniques are clarified and validated through three case studies, including beverage brewers and
material-removal products. The results of these case studies are argued to have significant impact on design-by-analogy procedures,
benchmarking methods, mass customization strategies and modular design. The paper concludes with a discussion of applications
and related procedures for product development. 相似文献
18.
Karl-Heinz Küfer Alexander Scherrer Michael Monz Fernando Alonso Hans Trinkaus Thomas Bortfeld Christian Thieke 《OR Spectrum》2003,25(2):223-249
Abstract. Radiation therapy planning is often a tight rope walk between dangerous insufficient dose in the target volume and life threatening
overdosing of organs at risk. Finding ideal balances between these inherently contradictory goals challenges dosimetrists
and physicians in their daily practice. Todays inverse planning systems calculate treatment plans based on a single evaluation
function that measures the quality of a radiation treatment plan. Unfortunately, such a one dimensional approach cannot satisfactorily
map the different backgrounds of physicians and the patient dependent necessities. So, too often a time consuming iterative
optimization process between evaluation of the dose distribution and redefinition of the evaluation function is needed. In
this paper we propose a generic multi-criteria approach based on Pareto's solution concept. For each entity of interest –
target volume or organ at risk – a structure dependent evaluation function is defined measuring deviations from ideal doses
that are calculated from statistical functions. A reasonable bunch of clinically meaningful Pareto optimal solutions are stored
in a data base, which can be interactively searched by physicians. The system guarantees dynamic planning as well as the discussion
of tradeoffs between different entities. Mathematically, we model the inverse problem as a multi-criteria linear programming
problem. Because of the large scale nature of the problem it is not possible to solve the problem in a 3D-setting without
adaptive reduction by appropriate approximation schemes. Our approach is twofold: First, the discretization of the continuous
problem results from an adaptive hierarchical clustering process which is used for a local refinement of constraints during
the optimization procedure. Second, the set of Pareto optimal solutions is approximated by an adaptive grid of representatives
that are found by a hybrid process of calculating extreme compromises and interpolation methods.
Correspondence to: K.-H. Küfer 相似文献
19.
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
20.
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