Robert Adonyi - Academia.edu (original) (raw)

Papers by Robert Adonyi

Research paper thumbnail of Optimal Schedule of a Dairy Manufactory

Chemical and Biochemical Engineering Quarterly

This paper deals with short-term scheduling of the dairy industry. Two different approaches are p... more This paper deals with short-term scheduling of the dairy industry. Two different approaches are proposed for obtaining the minimal makespan schedules. According to the first, S-graph framework is proposed to find the optimal solution of the flow-shop scheduling problem. The problem is solved by applying the branch and bound technique. The second approach uses the integer programming formulation of the scheduling problem and BASIC genetic algorithm has been used to solve the optimization problem. Both approaches take into consideration volumes of units assigned to perform tasks, and respective size factors that affect the size of batches and their number must be produces to achieve production goals and thus on the schedules duration. Manufacturing of two type curds is used as a case study. The results obtained show that both approaches provide comparable solutions. Both approaches could be seen as a good alternative to project manager to find appropriate schedule of the dairy industry.

Research paper thumbnail of Integrated synthesis of process and heat exchanger networks: algorithmic approach

Applied Thermal Engineering, 2001

Methods exist for algorithmic process-network synthesis (PNS) as well as for heat-exchanger-netwo... more Methods exist for algorithmic process-network synthesis (PNS) as well as for heat-exchanger-network synthesis (HENS); nevertheless, such methods cannot be easily integrated for a variety of reasons. For instance, both PNS and HENS are complex problems; thus, their combination is naturally even more complex. Our previous eort to establish the combinatorial foundation of PNS has yielded a highly eective method involving the P-graph representation; the present approach to the integrated synthesis of process and heat-exchanger networks resorts mainly to hP-graphs adapted from the P-graphs in conjunction with the appropriate selection of inherent intervals of temperature range. This work focuses on the establishment of an appropriate technique for the integration of PNS and HENS. The resultant technique is largely based on combinatorics and combinatorial algorithms. The ecacy of the proposed approach is illustrated by solving an industrial problem.

Research paper thumbnail of Routing of Railway Systems with the S-graph Framework for Effective Scheduling

In the present work, the S-graph framework has been adopted for solving the routing and schedulin... more In the present work, the S-graph framework has been adopted for solving the routing and scheduling of railway systems. The proposed method can be effectively integrated into the overall supply chain management, including production and distribution systems. The scheduling of a large-scale production system with batch and continuous operations is a complex optimization problem. The formerly developed S-graph framework (Sanmarti et. al. 1998, 2002) is proven to be highly effective for multi-purpose batch scheduling. This framework has been extended to handle the routing of railway systems. Optimal scheduling of a railway system becomes extremely complex if a large number of trains are considered. In most cases, however, the search space of the optimization procedure can be reduced substantially by eliminating redundant solutions through additional combinatorial constraints. The proposed methodology aims to achieve this reduction. The problem is represented by a directed graph, which c...

Research paper thumbnail of Incorporating heat integration in batch process scheduling

Applied Thermal Engineering, 2003

This work presents a methodology for incorporating heat integration in batch process scheduling. ... more This work presents a methodology for incorporating heat integration in batch process scheduling. The formerly introduced S-graph approach [AIChE J. 48 (2002) 2557-2570] for solving multipurpose scheduling problems is proved to be appropriate for the representation of both scheduling problems and the corresponding heat exchanger network synthesis problem. The proposed procedure is based on the branch-andbound framework, where two optimisation problems, the scheduling and the heat integration one, are considered simultaneously instead of consecutively. This method is primarily based on combinatorics and combinatorial algorithms. Solution of several examples illustrates the efficiency of the proposed approach and the benefits of considering heat exchanger network synthesis while scheduling batch processes.

Research paper thumbnail of Scheduling of bus maintenance by the P-graph methodology

Optimization and Engineering, 2013

Research paper thumbnail of Superstructure Approach to Batch Process Scheduling by S graph Representation

ABSTRACT Scheduling plays a key role in batch process operation; it has a major effect on the pro... more ABSTRACT Scheduling plays a key role in batch process operation; it has a major effect on the process' performance. Available methods for determining the optimal schedule are primarily based on either MILP/MINLP formulation in conjunction with mathematical programming (Floudas and Lin, 2004; Vaklieva-Bancheva and Kirilova, 2010) or graph representation in conjunction with combinatorial algorithms (Sanmarti et al., 2002).The current work comprises three major contributions. First, an algorithm has been crafted to generate a superstructure for a scheduling problem. The problem is defined in the form of an S-graph representing the recipe. The superstructure contains exclusively every step potentially performed by any of the functional or operating facilities or equipment units capable of completing at least one task to be scheduled. These steps involve executions of tasks and changeovers from one task to another. Second, an MILP formulation is elaborated on the basis of the superstructure, which guarantees the optimal solution of the scheduling problem. Third, a relaxation of the MILP model is incorporated into the S-graph algorithms to support the selection of subproblems and decision variables in the branch-and-bound procedure.

Research paper thumbnail of Effective scheduling of a large-scale paint production system

Due to the large variety of options offered to customers, batch production schemes are highly acc... more Due to the large variety of options offered to customers, batch production schemes are highly accepted in the paint industry implying that scheduling plays an important role in optimal allocation of plant resources among multiple products. Since in a batch process, the cleaning of equipment units is the major source of waste, waste minimization is also to be taken into account in determining the schedule. The formerly developed S-graph framework [Sanmartí E, Holczinger T, Puigjaner L, Friedler F. Combinatorial framework for effective scheduling of multipurpose batch plants. AIChE Journal 2002;48(11):2557e70.] proved to be highly effective in solving multipurpose batch scheduling; it has now been specialized for solving paint production scheduling problems including waste minimization. The efficacy of the new approach is illustrated with the solution of large-scale paint production scheduling problems.

Research paper thumbnail of Optimal Schedule of a Dairy Manufactory

Chemical and Biochemical Engineering Quarterly

This paper deals with short-term scheduling of the dairy industry. Two different approaches are p... more This paper deals with short-term scheduling of the dairy industry. Two different approaches are proposed for obtaining the minimal makespan schedules. According to the first, S-graph framework is proposed to find the optimal solution of the flow-shop scheduling problem. The problem is solved by applying the branch and bound technique. The second approach uses the integer programming formulation of the scheduling problem and BASIC genetic algorithm has been used to solve the optimization problem. Both approaches take into consideration volumes of units assigned to perform tasks, and respective size factors that affect the size of batches and their number must be produces to achieve production goals and thus on the schedules duration. Manufacturing of two type curds is used as a case study. The results obtained show that both approaches provide comparable solutions. Both approaches could be seen as a good alternative to project manager to find appropriate schedule of the dairy industry.

Research paper thumbnail of Integrated synthesis of process and heat exchanger networks: algorithmic approach

Applied Thermal Engineering, 2001

Methods exist for algorithmic process-network synthesis (PNS) as well as for heat-exchanger-netwo... more Methods exist for algorithmic process-network synthesis (PNS) as well as for heat-exchanger-network synthesis (HENS); nevertheless, such methods cannot be easily integrated for a variety of reasons. For instance, both PNS and HENS are complex problems; thus, their combination is naturally even more complex. Our previous eort to establish the combinatorial foundation of PNS has yielded a highly eective method involving the P-graph representation; the present approach to the integrated synthesis of process and heat-exchanger networks resorts mainly to hP-graphs adapted from the P-graphs in conjunction with the appropriate selection of inherent intervals of temperature range. This work focuses on the establishment of an appropriate technique for the integration of PNS and HENS. The resultant technique is largely based on combinatorics and combinatorial algorithms. The ecacy of the proposed approach is illustrated by solving an industrial problem.

Research paper thumbnail of Routing of Railway Systems with the S-graph Framework for Effective Scheduling

In the present work, the S-graph framework has been adopted for solving the routing and schedulin... more In the present work, the S-graph framework has been adopted for solving the routing and scheduling of railway systems. The proposed method can be effectively integrated into the overall supply chain management, including production and distribution systems. The scheduling of a large-scale production system with batch and continuous operations is a complex optimization problem. The formerly developed S-graph framework (Sanmarti et. al. 1998, 2002) is proven to be highly effective for multi-purpose batch scheduling. This framework has been extended to handle the routing of railway systems. Optimal scheduling of a railway system becomes extremely complex if a large number of trains are considered. In most cases, however, the search space of the optimization procedure can be reduced substantially by eliminating redundant solutions through additional combinatorial constraints. The proposed methodology aims to achieve this reduction. The problem is represented by a directed graph, which c...

Research paper thumbnail of Incorporating heat integration in batch process scheduling

Applied Thermal Engineering, 2003

This work presents a methodology for incorporating heat integration in batch process scheduling. ... more This work presents a methodology for incorporating heat integration in batch process scheduling. The formerly introduced S-graph approach [AIChE J. 48 (2002) 2557-2570] for solving multipurpose scheduling problems is proved to be appropriate for the representation of both scheduling problems and the corresponding heat exchanger network synthesis problem. The proposed procedure is based on the branch-andbound framework, where two optimisation problems, the scheduling and the heat integration one, are considered simultaneously instead of consecutively. This method is primarily based on combinatorics and combinatorial algorithms. Solution of several examples illustrates the efficiency of the proposed approach and the benefits of considering heat exchanger network synthesis while scheduling batch processes.

Research paper thumbnail of Scheduling of bus maintenance by the P-graph methodology

Optimization and Engineering, 2013

Research paper thumbnail of Superstructure Approach to Batch Process Scheduling by S graph Representation

ABSTRACT Scheduling plays a key role in batch process operation; it has a major effect on the pro... more ABSTRACT Scheduling plays a key role in batch process operation; it has a major effect on the process' performance. Available methods for determining the optimal schedule are primarily based on either MILP/MINLP formulation in conjunction with mathematical programming (Floudas and Lin, 2004; Vaklieva-Bancheva and Kirilova, 2010) or graph representation in conjunction with combinatorial algorithms (Sanmarti et al., 2002).The current work comprises three major contributions. First, an algorithm has been crafted to generate a superstructure for a scheduling problem. The problem is defined in the form of an S-graph representing the recipe. The superstructure contains exclusively every step potentially performed by any of the functional or operating facilities or equipment units capable of completing at least one task to be scheduled. These steps involve executions of tasks and changeovers from one task to another. Second, an MILP formulation is elaborated on the basis of the superstructure, which guarantees the optimal solution of the scheduling problem. Third, a relaxation of the MILP model is incorporated into the S-graph algorithms to support the selection of subproblems and decision variables in the branch-and-bound procedure.

Research paper thumbnail of Effective scheduling of a large-scale paint production system

Due to the large variety of options offered to customers, batch production schemes are highly acc... more Due to the large variety of options offered to customers, batch production schemes are highly accepted in the paint industry implying that scheduling plays an important role in optimal allocation of plant resources among multiple products. Since in a batch process, the cleaning of equipment units is the major source of waste, waste minimization is also to be taken into account in determining the schedule. The formerly developed S-graph framework [Sanmartí E, Holczinger T, Puigjaner L, Friedler F. Combinatorial framework for effective scheduling of multipurpose batch plants. AIChE Journal 2002;48(11):2557e70.] proved to be highly effective in solving multipurpose batch scheduling; it has now been specialized for solving paint production scheduling problems including waste minimization. The efficacy of the new approach is illustrated with the solution of large-scale paint production scheduling problems.