Shokri Selim

King Fahd University of Petroleum and Minerals | KFUPM · Department of Systems Engineering

This paper introduces discrete production systems where units are produced one at a time. These systems exist in industry but to the best of our knowledge, they have not been addressed in the open literature. Manufacturing of large iron castings and special precast panels are examples of such production systems. We consider the case where the produ...

Increasing global warming, climate change and stringent governmental legislations are driving industry practitioners and decision makers to implement various strategies to reduce carbon emissions. One of the effective approaches to mitigate carbon emissions is the implementation of closed-loop supply chain (CLSC). The key motivation for considering...

The present disclosure relates to a clustering approach for sensor nodes of a wireless sensor network. This clustering approach, equal distance different members, balances the power burden amongst sensor nodes by deriving an optimal number of sensor nodes at each segment of a length. To this end, the present disclosure describes a linear wireless s...

The literature has several models that jointly determine the economic production quantity (EPQ) and the rate of production. Very few models define production rate explicitly. In this article, the cutting speed controls the production rate and the proportion nonconforming. Thus, we propose a model that integrates EPQ, machining economics and quality...

This paper presents a generalized targeting model that subsumes most known targeting problems. In this paper, a recurrent state is defined as a condition that requires reprocessing or rework. The generalized model can accommodate one or two specifications limits and can be used for the following quality characteristics: The nominal-the-better, the...

In this paper, we consider the selective newsvendor problem (SNVP), where the decision maker selects the optimal set of markets to serve and the optimal order quantity to procure. We consider the case of a single product SNVP with uncertain demand data of unknown probability distributions for some of the potential markets. We present robust models...

To maximize profitability and meet customers' expectations, assembly plants strive to enhance operations and minimize costs. Using discrete-event system simulation and optimization, this paper investigates different scenarios to enhance operations efficiency and presents a decision support tool to aid operational decision making in an air condition...

The adoption of closed-loop supply chain (CLSC) network is one of the effective approaches to reduce carbon emissions. In current globalization, inherent uncertainty exists in business environment so there is a need to be design robust supply chains. This paper proposes a deterministic mixed integer linear programming (MILP) model integrating econo...

Traditional approaches to supply chain planning consider planning problems under the assumption that all demand sources should be satisfied. However, in the real world, firms have limited resources, therefore, planning approaches must take the capacity of these resources into consideration and select the optimal set of demands to satisfy. This stud...

Climate change attributed by greenhouse gas emissions have triggered some countries to implement various carbon regulatory mechanisms to curb and regulate industrial carbon emissions. To be effective, the industry environmental footprint needs to address holistically via closed-loop supply chains (CLSC). This research proposes an optimization appro...

The binomial Exponentially Weighted Moving Average (EWMA) control chart has been widely used as an effective tool for detecting small and moderate shifts in fraction nonconforming (p). This article presents a binomial EWMA chart employing a curtailment technique (abridged as Curt_EWMA chart) for monitoring p. The p shift is assumed to follow a Rayl...

We consider a multi-product multi-market newsvendor problem where the decision-maker could select some markets to serve. The considered problem involves the integration of procurement and market selection decisions. The products are procured from an external supplier. We assume that the realised demand for each product should be satisfied. In the c...

We study the CVaR risk-averse Multi-Product Selective Newsvendor Problem (MPSNVP). The MPSNVP involves the integration of the procurement decisions with the market selection decisions. Prior to the demand realization, the decision maker has to select markets (from available markets) to serve, and decide the order quantity for each product, in order...

The load-carrying capacity of an eccentrically loaded reinforced concrete column affected by corrosion of reinforcement will progressively decrease with time due to the buildup of corrosion-induced damage in the form of loss of reinforcement area, cracking and spalling of concrete cover. Due to the complexity of corrosion problems, a probability-ba...

Purpose – The purpose of this paper is to compare the performance of the genetic algorithm (GA), simulate annealing (SA) and shuffled frog-leaping algorithm (SFLA) in solving discrete versus continuous-variable optimization problems of the finance-based scheduling. This involves the minimization of the project duration and consequently the time-rel...

Wireless Sensor Network (WSN) enables pervasive, ubiquitous, and seamless communication with the physical world. This paper investigates an optimal cross-layer optimization for WSN with periodic application. A joint energy efficient routing with minimum delay scheduling optimization model is proposed in this paper. The problem is formulated as an I...

Due to increase in environmental concerns along with stringent government legislations, forcing industry practitioners and policy makers to take a fresh look at the impact of their supply chain activities on the environment. Various carbon regulatory mechanisms have been proposed by governmental agencies around the globe, which aims to curb the car...

In this paper, we study the problem of base stations location and configuration. Antenna configuration includes number of antennas installed at the base station, the azimuth of each base station, the tilt, height, and transmitted power for each antenna for cellular mobile networks. Towards this end, a mathematical model is formulated using integer...

This paper investigates an optimal cross-layer joint routing and scheduling problem for WSN with periodic data collection. The problem is formulated as an Integer Linear Program (ILP) model such that a joint scheduling and routing is developed to maximize network lifetime. An ILP model for Energy-Efficient Distributed Schedule-Based (EEDS) protocol...

Wireless Sensor Network (WSN) enables pervasive, ubiquitous, and seamless communication with the physical world. This paper investigates an optimal cross-layer joint routing and scheduling problem for WSN with periodic data collection. The problem is formulated as an Integer Linear Program (ILP) model such that a joint scheduling and routing is dev...

This paper proposes a hybrid evolutionary algorithm for solving the constrained multipath traffic engineering problem in MPLS (Multi-Protocol Label Switching) network and its extended architecture GMPLS (Generalized MPLS). Multipath traffic engineering is gaining more importance in contemporary networks. It aims to satisfy the requirements of emerg...

Currently, the genetic algorithm (GA) technique has been used in finance-based scheduling to devise critical path method (CPM) schedules exhibiting cash flows of periodical finance needs below preset cash constraints. The chromosomes of the schedules that violate this condition are referred to as finance-infeasible chromosomes. Infeasibility relate...

We consider a manufacturing process that generates non-conforming items until proper adjustment of the process is reached. Items produced after machine adjustment are assume perfect. The demand rate is assumed constant. The process stops when the production of conforming items is sufficient to cover the demand, then the cycle is repeated perpetuall...

In this study, an improved observer-based stabilising controller has been designed for networked systems involving both random measurement and actuation delays and subject to non-stationary packet dropouts. The developed control algorithm is suitable for networked systems with any type of delays. By the simultaneous presence of binary random delays...

Currently, meta-heuristics including the genetic algorithms (GA) and simulated annealing (SA) have been used extensively to solve non-deterministic polynomial-time hard (NP-hard) problems. Continued efforts of researchers to upgrade the performance of the meta-heuristics in use resulted in the evolution of new ones. Shuffled frog-leaping algorithm...

Oil and Gas industry shows great interest in deploying wireless sensor network for monitoring smart wells. The deployed sensors are very expensive and it is important to minimize the deployment cost while satisfying the coverage and connectivity requirements. In this work, we present a coverage-connectivity model for optimal deployment of sensors a...

We discuss the problem of determining the means of a set of processes in series. Each process generates a random quality characteristic that in turn has lower and upper specification limits. Depending on the value of the quality characteristic, an item can be reworked, scrapped or forwarded to the next process. An item is reworked at the same stage...

The problem of global exponential stability analysis for a class of neural networks (NNs) with probabilistic delays is discussed in this paper. The delay is assumed to follow a given probability density function. This function is discretised into arbitrary number of intervals. In this way, the NN with random time delays is transformed into one with...

In this paper, new results are established for generating tracking policies in aggregated production-inventory systems. A dynamic model is developed to characterize the evolution of targeted production, inventory and demand over time and incorporates the inventory, production and demand tracking errors as additional variables. The control variables...

There are basic design elements in Wireless Local Area Networks (WLAN) architecture to provide good service for the users like locations, number and transmission power of the Access Points (APs), also known as Base Stations (BSs). The number of deployed stations has a direct impact on the cost of the WLAN. Moreover, the intercell interference is af...

This paper presents a flexible evolutionary method for minimum-cost multipath constrained routing with load balancing problem in MPLS networks. The proposed solution approach combines genetic algorithms with linear multi-commodity flow to enhance the efficiency of the solution attained. The goal is to determine the distribution of traffic demands o...

Attention has recently focused on the low frequency electromagnetic fields in homes. Public are interested in knowing the domestic EMF fields to help determine whether exposure to these fields causes ill health and, in particular, to provide measure of the EMF environment for an epidemiological survey. Information on the sources of home electromagn...

In today's online connected world, almost all corporate networks use some form of perimeter firewalls to manage Internet connections and enforce a security policy at the corporate gateway. Although it can considerably enhance network security and protect business-critical information, a firewall with thousands of rules can become a bottleneck for n...

In this paper, we consider joint scheduling of jobs and preventive maintenance operations on a single machine with an objective to minimize the total earliness and tardiness of jobs about a common due date. The properties of an optimal schedule are identified and utilized to develop a constructive heuristic and a lower bound estimate. The propertie...

Two formulations of capacitor placement problem (CPP) are presented. One is based on capacitors/losses cost balance. The other is based on comprehensive cost evaluation of network performance post CP. GA based program is implemented to solve CPP. Proposed solution technique is tested on 69-bus system reported in the literature. In addition, impact...

This paper presents an algorithm for computing the distance between two circular disks in three-dimensional space. A Kurush–Kuhn–Tucker (KKT) approach is used to solve the problem. We show that when the optimal points are not both at the borders of disks, the solutions of the KKT equations can be obtained in closed-form. For the case where the poin...

A new combinatorial algorithm is presented, which has potential applications in cyclic scheduling. Specifically, the question is: given n cyclic objects, how many cyclically distinct combinations of m (m ≤ n) objects can be selected? In other words, if a subset m of these objects has one color, and the remaining (n – m) objects have another color,...

In this paper, we consider a collision detection problem that frequently arises in the field of robotics. Given a set of bodies with their initial positions and trajectories, we wish to identify the first collision that occurs between any two bodies, or to determine that none exists. For the case of bodies having linear trajectories, we construct a...

Machine malfunction may be detected from the change in its noise level sensed by the ear or measured by a sound level meter. When various machines run concurrently in a workshop, it is not easy to detect noise change. This paper presents the development of a system of equations relating to the combined noise level at each machine with the individua...

In this paper we consider the problem of scheduling n jobs on a single machine that is subject to random breakdowns. The performance measure is a function of the expected deviation from the due window the window size and location and the expected mean completion time. The location of the due date and the size of the window are determined as a funct...

This paper presents a new algorithm based on integrating genetic algorithms, tabu search and simulated annealing methods to solve the unit commitment problem. The core of the proposed algorithm is based on genetic algorithms. Tabu search is used to generate new population members in the reproduction phase of the genetic algorithm. A simulated annea...

This paper presents a new algorithm based on integrating the use of genetic algorithms and tabu search methods to solve the unit commitment problem. The proposed algorithm, which is mainly based on genetic algorithms incorporates tabu search method to generate new population members in the reproduction phase of the genetic algorithm. In the propose...

In this paper, an explicit mathematical representation of n-dimensional bodies moving in translation along general trajectories is derived. This representation is used to find out if two moving bodies are going to collide. An optimization problem is developed for finding the time and location of collision. We consider the special cases of linear an...

The public are interested in knowing the sources of domestic magnetic and electric fields to help determine whether exposure to these fields causes ill health and in particular, to provide a measure of the electromagnetic environment for an epidemiological survey. First, consideration should be given to the various factors to be borne in mind conce...

This paper presents a simulated annealing algorithm (SAA) to solve the unit commitment problem (UCP). New rules for randomly generating feasible solutions are introduced. The problem has two subproblems: a combinatorial optimization problem; and a nonlinear programming problem. The former is solved using the SAA while the latter problem is solved v...

An application of the tabu search (TS) method to solve the unit commitment problem (UCP) is presented. The TS seeks to counter the danger of entrapment at a local optimum by incorporating a memory structure that forbids or penalises certain moves that would return to recently visited solutions. New rules for randomly generating feasible solutions f...

We propose a new hybrid algorithm for solving the unit commitment problem (UCP). The algorithm integrates the use of simulated annealing (SA) and tabu search (TS) for solving the UCP. The algorithm includes a step to find an initial control parameter, at which virtually all trial solutions are accepted. It uses a polynomial-time cooling schedule th...

This paper presents a new genetic algorithm approach to solve the unit commitment problem in electric power systems. In the proposed algorithm, coding the solution of the unit commitment problem is based on mixing binary and decimal representations. A fitness function is constructed from the total operating cost of the generating units without pena...

The paper demonstrates the use of genetic algorithms to design output feedback power system stabilizers. Two methods are presented: in the first method, the problem is formulated as an optimization problem with a standard infinite time quadratic objective function. A digital simulation of the power system is then used in conjunction with the geneti...

This paper considers the problem of designing controllers to place simultaneously the closedloop eigenvalues of a finite number of plants, representing different operating conditions of a system, in a specific region in the left half of the complex s plane. The problem of selecting the controller gains is converted to a simple optimization problem...

One of the rituals of the Moslem pilgrimage to Makkah is Tawaf. For Tawaf, a pilgrim walks seven times around the Ka'aba. The Ka'aba is a cubic structure. The area available around the Ka'aba is relatively small and is usually congested. People arrive at random to perform this ritual and immediately join the crowd, further congesting the area. The...

This paper considers a robust linear-quadratic (LQ) control problem for nominally linear systems with norm-bounded uncertainties. The uncertainties appear in all system matrices and do not satisfy matching conditions. A linear matrix inequality (LMI) approach is developed for constructing an output-feedback control law which guarantees the quadrati...

We consider the queueing system denoted by M/M N /1/N, where customers are served in batches of maximum size N. The model is motivated by a traffic application. The time-dependent probability distribution for the number of customers in the system is obtained in closed form. The solution is used to predict the optimal service rates during a finite t...

We consider the queueing system denoted by M/MN /1/N where customers are served in batches of maximum size N. The model is motivated by a traffic application. The time-dependent probability distribution for the number of customers in the system is obtained in closed form. The solution is used to predict the optimal service rates during a finite tim...

Material and production control (MPC) techniques are essential tools to be used in industry in order to achieve high quality products and low production cost. For a country like Saudi Arabia that is venturing into the industrial era, achievement of success and standing to competition require the implementation of up-to-date MPC tools. The purpose o...

In this paper we address the problem of selecting a set of wind directions that could represent the wind regime at a location. This problem is cast in the form of a non-convex mathematical program. Important properties of the problem are discussed and a convergent solution algorithm is designed. The algorithm could yield local optimal solutions. A...

Two new algorithms for fuzzy clustering are presented. Convergence of the proposed algorithms is proved. An empirical study of their convergence behavior is discussed. The performance of the new algorithms is compared with the fuzzy c-means algorithm by testing them on four published data sets. Experimental results show that the new algorithms are...

In this paper a new algorithm for fuzzy clustering is presented. The proposed algorithm utilizes the idea of relaxation. Convergence of the proposed algorithm is proved and limits on the relaxation parameter are derived. Stopping criteria and resulting convergence behaviour of the algorithms are discussed. The performance of the new algorithm is co...

Let and be bounded polyhedral sets. Let . Consider the minimization of f(u.v) subject to uU vV. For fixed v fis linear in u and for fixed U U. it is convex in v. If f is the global minimum function value, then there is at least one vertex u U such that for some v We characterize KARUSH-KUHN-TUCKER and local minimum points of the problem. An algorit...

The Fuzzy clustering (FC) problem is a non-convex mathematical program which usually possesses several local minima. The global minimum solution of the problem is found using a simulated annealing-based algorithm. Some preliminary computational experiments are reported and the solution is compared with that generated by the Fuzzy C-means algorithm.

The problem of sequencing jobs on a weaving machine is considered where set-up costs are included. The structure of the set-up cost is utilized to develop a polynomial time solution algorithm. The algorithm involves computing the shortest path of a network. An example is solved.

The ‘fuzzy clustering’ problem is investigated. Interesting properties of the points generated in the course of applying the fuzzy c-means algorithm are revealed using the concept of reduced objective function. We investigate seven quantities that could be used for stopping the algorithm and prove relationships among them. Finally, we empirically s...

Summary In this paper we discuss the solution of the cluste ring problem usually solved by the K-means algorithm. The problem is known to have local minimum solutions which are usually what the K-means algorithm obtains. The simulated annealing approach for solving optimization problems is described and is proposed for solving the clustering proble...

In this paper, the problem of achieving “semi-fuzzy” or “soft” clustering of multidimensional data is discussed. A technique based on thresholding the results of the fuzzy c-means algorithm is introduced. The proposed approach is analysed and contrasted with the soft clustering method (see S. Z. Selim and M. A. Ismail, Pattern Recognition17, 559–56...

During the Moslem pilgrimage season the Jamarat bridge becomes congested with pilgrims, due to space and time constraints. This paper aims at developing a model for regulating pedestrain flow into the bridge. The model may provide facility designers and managers with a quantitative tool for predicting the level of congestion at specific regions on...

A distribution identification method is developed in the paper. The method derives a sequence of characteristic standardized moment ratios for a class of common continuous distribution. The use of the method has been demonstrated via several examples of identifying hypothesized random variables. The method correctly identified the hypothesized dist...

Kim et al. (Pattern Recognition21, 651–663, 1988) claimed that Ismail and Selim, Pattern Recognition19, 481 (1986) and Selim and Ismail IEEE Trans. Pattern Anal. Mach. Intell.PAMI-8, 284–288 (1986) contained errors. In this note we dismiss this claim.

In this paper, the solutions produced by the fuzzy c-means algorithm for a general class of problems are examined and a method to test for the local optimality of such solutions is established. An equivalent mathematical program is defined for the c-means problem utilizing a generalized norm, then the properties of the resulting optimization proble...

The convergence of the fuzzy ISODATA clustering algorithm was proved by Bezdek [3]. Two sets of conditions were derived and it was conjectured that they are necessary and sufficient for a local minimum point. In this paper, we address this conjecture and explore the properties of the underlying optimization problem. The notions of reduced objective...

This paper discusses new approaches to unsupervised fuzzy classification of multidimensional data. In the developed clustering models, patterns are considered to belong to some but not necessarily all clusters. Accordingly, such algorithms are called ‘semi-fuzzy’ or ‘soft’ clustering techniques. Several models to achieve this goal are investigated...

The K-means algorithm is a commonly used technique in cluster analysis. In this paper, several questions about the algorithm are addressed. The clustering problem is first cast as a nonconvex mathematical program. Then, a rigorous proof of the finite convergence of the K-means-type algorithm is given for any metric. It is shown that under certain c...

Thesis (Ph. D.)--Georgia Institute of Technology. Directed by Chitharanjan Marakada Shetty. (U.M. order no. 80-10,007). Vita. Includes bibliographical references (leaves 151-156).