Ahmet Bolat

Yildiz Technical University · Department of Industrial Engineering

The crew pairing problem (CPP) deals with generating crew pairings due to law and restrictions and selecting a set of crew pairings with minimal cost that covers all the flight legs. In this study, we present three different algorithms to solve CPP. The knowledge based random algorithm (KBRA) and the hybrid algorithm (HA) both combine heuristics an...

The capacity of pumping ground water with wind energy conversion systems in Dhahran, Saudi Arabia was statistically analyzed. Experimental data of half-hourly wind energy measurements made for a period of 5years (1995–2000) were used in the analysis. Seven horizontal-axis wind turbines with different power ratings were considered in the study. Eigh...

http://deepblue.lib.umich.edu/bitstream/2027.42/3711/5/bal9378.0001.001.pdf http://deepblue.lib.umich.edu/bitstream/2027.42/3711/4/bal9378.0001.001.txt

http://deepblue.lib.umich.edu/bitstream/2027.42/3710/5/bbl2269.0001.001.pdf http://deepblue.lib.umich.edu/bitstream/2027.42/3710/4/bbl2269.0001.001.txt

This paper addresses the problem of scheduling jobs for three serial stations with the last two duplicate, i.e., identical. The performance measure considered is the makespan, and a Branch and Bound and two heuristic procedures are proposed. Two dominance criteria are developed to produce the optimal schedule for the jobs sequenced so far. Extensiv...

The performance of a sequencing procedure to smooth out the fluctuating workload (and part utilization) on a paced assembly line relies heavily on the average load of the model mixes chosen from the order-bank. Meanwhile, the due-dates of orders may conflict with this production-centred goal. This study proposes a mathematical model to select a fix...

Assigning aircraft to available gates at an airport can have a major impact on the efficiency of flight schedules and on the level of passenger satisfaction with the service. Unexpected changes, due to air traffic delays, severe weather conditions, or equipment failures, may disrupt the initial assignments and compound the difficulty of maintaining...

Today, custom and shipping regulations recognize the importance of lightweight and high performance corrugated boxes, and encourage wider usage of them. Usually, the boxes are produced by glueing layers of paper from roll stocks and cutting carton boards in certain sizes in the corrugater machine, drying them in the buffer area, and converting the...

Assigning commercial service aircrafts to the available gates at an airport depends on flights scheduled, their actual behavior relative to those schedules, aircraft servicing requirements and capacities of ramp facilities. Flight delays, severe weather, or equipment failures can disrupt the planned schedules, and compound the difficulty of maintai...

Unexpected changes in the flight schedules may disrupt the initial aircraft-gate assignments, and result in congestions and delays in getting aircraft onto gates. A mathematical model is developed to assign the flights with the minimum range of unutilised time periods of gates, subject to the level of service offered to passengers and other physica...

Unexpected changes in the flight schedules may disrupt the initial aircraft-gate assignments, and result in congestions and delays in getting aircraft onto gates. A mathematical model is developed to assign the flights with the minimum range of unutilised time periods of gates, subject to the level of service offered to passengers and other physica...

For sequencing different models on a paced assembly line, the commonly accepted objective is to keep the operators within the boundaries of their stations. When the operators reach the right boundary, they terminate the operation prematurely. In this article we address the problem of sequencing jobs decomposed into identical and repeating sets to m...

In this article, we address the problem of how to sequence the jobs defined by a set of operations so that a well balanced Mixed Model Assembly Line is utilized efficiently. The objective depends on the management philosophy for completing the remaining work that cannot be done within the predefined boundaries of stations. We adopt the US philosoph...

This article deals with the real-time scheduling of jobs for an automated manufacturing module offering a variety of operations with negligible setup times. Since the jobs are brought to the system by a paced line at a fixed rate, each job is expected to be processed within a fixed cycle time. Hence, a group of jobs with longer processing-time may...

The task of assigning arriving flights to the available gates at an airport can have a major impact on the efficiency with which the flight schedules are maintained and on the level of passenger satisfaction. In this paper, optimum and heuristic procedures are developed to assign flights in such a way that the idle periods, during which gates are n...

The problem of how to sequence jobs with options on a mixed model assembly line without work-in-process storage has been well addressed in the literature. In almost all of the previously developed models, the common goal has been to generate schedules that would maximize the utilization of station capacities. However, the problem of setups and util...

Here a paced automobile assembly line is considered with no buffers between stations. Setup costs are incurred each time sequence of jobs switches colour in the paint shop, and utility work costs are incurred when some amount of work on a job cannot be completed within the boundary of a trim station. Although there has been a concerted effort to re...

In this note, we introduce a surrogate objective for utility work at a single station on a paced assembly line. We show that it is asymptotically equal to utility work as the number of jobs increases, and provide expressions for the worst-case difference between the two objectives. We also derive closed form expressions for the surrogate objective...

In this article we address the problem of sequencing jobs for one station on a paced assembly line with no buffers, at which two types of operations can be performed. We develop optimal solution procedures for three of four mutually exclusive and collectively exhaustive problem subclasses, with the goal of minimizing total utility work. For the fou...

http://deepblue.lib.umich.edu/bitstream/2027.42/3707/5/bal7903.0001.001.pdf http://deepblue.lib.umich.edu/bitstream/2027.42/3707/4/bal7903.0001.001.txt

Abstract ,This work deals with scheduling jobs for a flow-shop system consisted of three stages. There is one station in the first and one in the last stage, while there are two identical stations in the ,middle stage. There is no ,buffer between ,machines ,and the objective is to minimize the completion time of the last processed job. Identical st...

This work deals with scheduling jobs for a flow-shop system consisted of three stages. There is one station in the first and one in the last stage, while there are two identical stations in the middle stage. There is no buffer between machines and the objective is to minimize the completion time of the last processed job. Identical stations are uti...