Portfolio optimization refers to allocating an amount of investors’ wealth to different assets in... more Portfolio optimization refers to allocating an amount of investors’ wealth to different assets in order to satisfy the investors’ preferences for return and risk. We address the portfolio optimization problem with real-world constraints, where traditional optimization methods fail to efficiently find an optimal or near-optional solution. Hence, we design a modified cuckoo search (MCS) metaheuristic for finding good sub-optimal portfolios. Cuckoo search was inspired by the brood parasitism of cuckoo species by laying their eggs in the nests of other host birds. Our implementation explores the search space using Levy flights and allocates the good sub-optimal distribution of investment weights for a chosen set of assets. The MCS results show a clear improvement in comparison with previously published results, based on Markowitz and Sharpe models.
University exam timetabling refers to scheduling exams into predefined days, time periods and roo... more University exam timetabling refers to scheduling exams into predefined days, time periods and rooms, given a set of constraints. Exam timetabling is a computationally intractable optimization problem, which requires heuristic techniques for producing adequate solutions within reasonable execution time. For large numbers of exams and students, sequential algorithms are likely to be time consuming. This paper presents parallel scatter search meta-heuristic algorithms for producing good sub-optimal exam timetables in a reasonable time. Scatter search is a population-based approach that generates solutions over a number of iterations and aims to combine diversification and search intensification. The authors propose parallel scatter search algorithms that are based on distributing the population of candidate solutions over a number of processors in a PC cluster environment. The main components of scatter search are computed in parallel and efficient communication techniques are employed...
Proteins consist of sequences of amino acids that fold into 3-dimensional structures. The 3-dimen... more Proteins consist of sequences of amino acids that fold into 3-dimensional structures. The 3-dimensional configuration determines a protein’s function. Hence, it is very important to determine the correct structure in order to identify the wrong folding that indicates a disease situation. Computational protein structure prediction methods have been proposed in order to alleviate the enormous time taken by wet-lab methods. This paper presents a fragment-based protein tertiary structure prediction method which employs the CHARMM36 energy model. The method is based on a two-phase Scatter Search algorithm that minimizes the energy function. Backbone fragments are extracted from the Robetta server and side chains are, extracted from the Dunbrack Library. The results show that the algorithm produces tertiary structures with promising root mean square deviations. Keywords-protein structure prediction; scatter search; CHARMM36; protein fragments.
2016 IEEE 18th International Conference on e-Health Networking, Applications and Services (Healthcom), 2016
Patient information in healthcare organizations is distributed across several systems and data si... more Patient information in healthcare organizations is distributed across several systems and data silos. Clinicians make decisions based on data in patient health records. Improving the efficiency of decision-support requires collective knowledge of all patient information. The classical approach of linking patient data from many databases into one data warehouse poses various problems when it comes to building clinical analytics. An implementation of the Performance Measurement and Management approach used in Engineering and Business is adapted to healthcare scenarios, and a new system is developed that allows clinicians that are not technical professionals to develop, test and apply custom analytics to patient health data. Part I of this paper is an introduction to the problems and current situation in healthcare data analytics. Part II states the aim and objectives. Part III explains the system design and its modular components. Part IV presents the results of three performance indicators evaluated through the system, and evaluates the system through technical and clinical usability methods. Part V concludes and discusses future work.
Homology modeling is an effective technique in protein structure prediction (PSP). However this t... more Homology modeling is an effective technique in protein structure prediction (PSP). However this technique suffers from poor initial target-template alignments. To improve homology based PSP, we propose a scatter search (SS) metaheuristic algorithm. SS is an evolutionary approach that is based on a population of candidate solutions. These candidates undergo evolutionary operations that combine search intensification and diversification over a number of iterations. The metaheuristic optimizes the initial poor alignments and uses fitness functions. We assess our algorithm on a number of proteins whose structures are present in the Protein Data Bank and which have been used in previous literature. Results obtained by our SS algorithm are compared with other approaches. The 3D models predicted by our algorithm show improved root mean standard deviations with respect to the native structures.
Journal of Software Maintenance and Evolution: Research and Practice, 2011
In software maintenance, a system has to be regression tested after modifying it. The goal of reg... more In software maintenance, a system has to be regression tested after modifying it. The goal of regression testing is to ensure that modifications have not adversely affected the system. Regression test selection determines a subset of test cases, from the initial test suite, which ...
Journal of Software Maintenance and Evolution: Research and Practice, 2011
In software maintenance, a system has to be regression tested after modifying it. The goal of reg... more In software maintenance, a system has to be regression tested after modifying it. The goal of regression testing is to ensure that modifications have not adversely affected the system. Regression test selection determines a subset of test cases, from the initial test suite, which ...
Journal of Computational Methods in Sciences and Engineering
Abstract. Upon introducing a local change in a method or a class in an object oriented program, t... more Abstract. Upon introducing a local change in a method or a class in an object oriented program, the ripple effect gives a measure of the amount by which this change may affect other methods/classes. That is, the ripple effect shows maintainers the ramifications of any ...
Mapping data to parallel computers aims at minimizing the execution time of the associated applic... more Mapping data to parallel computers aims at minimizing the execution time of the associated application. However, it can take an unacceptable amount of time in comparison with the execution time of the application if the size of the problem is large. In this article, first we motivate the case for graph contraction as a means for reducing the problem size. We restrict our discussion to applications where the problem domain can be described using a graph (e.g., computational fluid dynamics applications). Then we present a mapping-oriented parallel graph contraction (PGC) heuristic algorithm that yields a smaller representation of the problem to which mapping is then applied. The mapping solution for the original problem is obtained by a straightforward interpolation. We then present experimental results on using contracted graphs as inputs to two physical optimization methods; namely, genetic algorithm and simulated annealing. The experimental results show that the PGC algorithm still...
ICECS 2000. 7th IEEE International Conference on Electronics, Circuits and Systems (Cat. No.00EX445), 2000
ABSTRACT: The problem addressed in this paper is that of decomposing a weighted graph into a spec... more ABSTRACT: The problem addressed in this paper is that of decomposing a weighted graph into a specified number of subgraphs such that these subgraphs have balanced sums of vertex weights and minimal sums of edge weights. To find a reasonable solution to this intractable ...
2010 Sixth International Conference on Natural Computation, 2010
Abstract. Exam timetabling is a computationally intractable problem, which requires heuristic tec... more Abstract. Exam timetabling is a computationally intractable problem, which requires heuristic techniques for producing good sub-optimal solutions within reasonable execution time. For large numbers of exams and students, sequential algorithms are likely to be time consuming. ...
Proceedings of the Acs Ieee 2005 International Conference on Computer Systems and Applications, Jan 3, 2005
Summary form only given. Web services present a promising software technology, which provides app... more Summary form only given. Web services present a promising software technology, which provides application-to-application interaction. They are based on communication protocols, service descriptions, and service discovery and are built on top of existing Web protocols and based on open XML standards. Web services are described using Web Services Description Language (WSDL), and the universal description, discovery, and integration directory provide a registry of Web services descriptions. Testing Web services is important for both the Web service provider and the Web service user. This paper proposes a technique for testing Web services using mutation analysis. The technique is based on applying mutation operators to the WSDL document in order to generate mutated Web service interfaces that are used to test the Web service. For this purpose, we define mutant operators that are specific to WSDL documents. Our empirical results have shown the usefulness of this technique.
Portfolio optimization refers to allocating an amount of investors’ wealth to different assets in... more Portfolio optimization refers to allocating an amount of investors’ wealth to different assets in order to satisfy the investors’ preferences for return and risk. We address the portfolio optimization problem with real-world constraints, where traditional optimization methods fail to efficiently find an optimal or near-optional solution. Hence, we design a modified cuckoo search (MCS) metaheuristic for finding good sub-optimal portfolios. Cuckoo search was inspired by the brood parasitism of cuckoo species by laying their eggs in the nests of other host birds. Our implementation explores the search space using Levy flights and allocates the good sub-optimal distribution of investment weights for a chosen set of assets. The MCS results show a clear improvement in comparison with previously published results, based on Markowitz and Sharpe models.
University exam timetabling refers to scheduling exams into predefined days, time periods and roo... more University exam timetabling refers to scheduling exams into predefined days, time periods and rooms, given a set of constraints. Exam timetabling is a computationally intractable optimization problem, which requires heuristic techniques for producing adequate solutions within reasonable execution time. For large numbers of exams and students, sequential algorithms are likely to be time consuming. This paper presents parallel scatter search meta-heuristic algorithms for producing good sub-optimal exam timetables in a reasonable time. Scatter search is a population-based approach that generates solutions over a number of iterations and aims to combine diversification and search intensification. The authors propose parallel scatter search algorithms that are based on distributing the population of candidate solutions over a number of processors in a PC cluster environment. The main components of scatter search are computed in parallel and efficient communication techniques are employed...
Proteins consist of sequences of amino acids that fold into 3-dimensional structures. The 3-dimen... more Proteins consist of sequences of amino acids that fold into 3-dimensional structures. The 3-dimensional configuration determines a protein’s function. Hence, it is very important to determine the correct structure in order to identify the wrong folding that indicates a disease situation. Computational protein structure prediction methods have been proposed in order to alleviate the enormous time taken by wet-lab methods. This paper presents a fragment-based protein tertiary structure prediction method which employs the CHARMM36 energy model. The method is based on a two-phase Scatter Search algorithm that minimizes the energy function. Backbone fragments are extracted from the Robetta server and side chains are, extracted from the Dunbrack Library. The results show that the algorithm produces tertiary structures with promising root mean square deviations. Keywords-protein structure prediction; scatter search; CHARMM36; protein fragments.
2016 IEEE 18th International Conference on e-Health Networking, Applications and Services (Healthcom), 2016
Patient information in healthcare organizations is distributed across several systems and data si... more Patient information in healthcare organizations is distributed across several systems and data silos. Clinicians make decisions based on data in patient health records. Improving the efficiency of decision-support requires collective knowledge of all patient information. The classical approach of linking patient data from many databases into one data warehouse poses various problems when it comes to building clinical analytics. An implementation of the Performance Measurement and Management approach used in Engineering and Business is adapted to healthcare scenarios, and a new system is developed that allows clinicians that are not technical professionals to develop, test and apply custom analytics to patient health data. Part I of this paper is an introduction to the problems and current situation in healthcare data analytics. Part II states the aim and objectives. Part III explains the system design and its modular components. Part IV presents the results of three performance indicators evaluated through the system, and evaluates the system through technical and clinical usability methods. Part V concludes and discusses future work.
Homology modeling is an effective technique in protein structure prediction (PSP). However this t... more Homology modeling is an effective technique in protein structure prediction (PSP). However this technique suffers from poor initial target-template alignments. To improve homology based PSP, we propose a scatter search (SS) metaheuristic algorithm. SS is an evolutionary approach that is based on a population of candidate solutions. These candidates undergo evolutionary operations that combine search intensification and diversification over a number of iterations. The metaheuristic optimizes the initial poor alignments and uses fitness functions. We assess our algorithm on a number of proteins whose structures are present in the Protein Data Bank and which have been used in previous literature. Results obtained by our SS algorithm are compared with other approaches. The 3D models predicted by our algorithm show improved root mean standard deviations with respect to the native structures.
Journal of Software Maintenance and Evolution: Research and Practice, 2011
In software maintenance, a system has to be regression tested after modifying it. The goal of reg... more In software maintenance, a system has to be regression tested after modifying it. The goal of regression testing is to ensure that modifications have not adversely affected the system. Regression test selection determines a subset of test cases, from the initial test suite, which ...
Journal of Software Maintenance and Evolution: Research and Practice, 2011
In software maintenance, a system has to be regression tested after modifying it. The goal of reg... more In software maintenance, a system has to be regression tested after modifying it. The goal of regression testing is to ensure that modifications have not adversely affected the system. Regression test selection determines a subset of test cases, from the initial test suite, which ...
Journal of Computational Methods in Sciences and Engineering
Abstract. Upon introducing a local change in a method or a class in an object oriented program, t... more Abstract. Upon introducing a local change in a method or a class in an object oriented program, the ripple effect gives a measure of the amount by which this change may affect other methods/classes. That is, the ripple effect shows maintainers the ramifications of any ...
Mapping data to parallel computers aims at minimizing the execution time of the associated applic... more Mapping data to parallel computers aims at minimizing the execution time of the associated application. However, it can take an unacceptable amount of time in comparison with the execution time of the application if the size of the problem is large. In this article, first we motivate the case for graph contraction as a means for reducing the problem size. We restrict our discussion to applications where the problem domain can be described using a graph (e.g., computational fluid dynamics applications). Then we present a mapping-oriented parallel graph contraction (PGC) heuristic algorithm that yields a smaller representation of the problem to which mapping is then applied. The mapping solution for the original problem is obtained by a straightforward interpolation. We then present experimental results on using contracted graphs as inputs to two physical optimization methods; namely, genetic algorithm and simulated annealing. The experimental results show that the PGC algorithm still...
ICECS 2000. 7th IEEE International Conference on Electronics, Circuits and Systems (Cat. No.00EX445), 2000
ABSTRACT: The problem addressed in this paper is that of decomposing a weighted graph into a spec... more ABSTRACT: The problem addressed in this paper is that of decomposing a weighted graph into a specified number of subgraphs such that these subgraphs have balanced sums of vertex weights and minimal sums of edge weights. To find a reasonable solution to this intractable ...
2010 Sixth International Conference on Natural Computation, 2010
Abstract. Exam timetabling is a computationally intractable problem, which requires heuristic tec... more Abstract. Exam timetabling is a computationally intractable problem, which requires heuristic techniques for producing good sub-optimal solutions within reasonable execution time. For large numbers of exams and students, sequential algorithms are likely to be time consuming. ...
Proceedings of the Acs Ieee 2005 International Conference on Computer Systems and Applications, Jan 3, 2005
Summary form only given. Web services present a promising software technology, which provides app... more Summary form only given. Web services present a promising software technology, which provides application-to-application interaction. They are based on communication protocols, service descriptions, and service discovery and are built on top of existing Web protocols and based on open XML standards. Web services are described using Web Services Description Language (WSDL), and the universal description, discovery, and integration directory provide a registry of Web services descriptions. Testing Web services is important for both the Web service provider and the Web service user. This paper proposes a technique for testing Web services using mutation analysis. The technique is based on applying mutation operators to the WSDL document in order to generate mutated Web service interfaces that are used to test the Web service. For this purpose, we define mutant operators that are specific to WSDL documents. Our empirical results have shown the usefulness of this technique.
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Papers by Nashat Mansour