Pinar, Ali
Overview
Works:  30 works in 31 publications in 2 languages and 77 library holdings 

Genres:  Criticism, interpretation, etc Selfinstruction Academic theses 
Roles:  Author, Other, Actor 
Classifications:  ML410.R3898, 510 
Publication Timeline
.
Most widely held works by
Ali Pinar
100. doğum yılında Cemal Reşit Rey(
Book
)
1 edition published in 2014 in Turkish and held by 10 WorldCat member libraries worldwide
1 edition published in 2014 in Turkish and held by 10 WorldCat member libraries worldwide
Highperformance combinatorial algorithms(
)
1 edition published in 2003 in English and held by 5 WorldCat member libraries worldwide
Combinatorial algorithms have long played an important role in many applications of scientific computing such as sparse matrix computations and parallel computing. The growing importance of combinatorial algorithms in emerging applications like computational biology and scientific data mining calls for development of a high performance library for combinatorial algorithms. Building such a library requires a new structure for combinatorial algorithms research that enables fast implementation of new algorithms. We propose a structure for combinatorial algorithms research that mimics the research structure of numerical algorithms. Numerical algorithms research is nicely complemented with high performance libraries, and this can be attributed to the fact that there are only a small number of fundamental problems that underlie numerical solvers. Furthermore there are only a handful of kernels that enable implementation of algorithms for these fundamental problems. Building a similar structure for combinatorial algorithms will enable efficient implementations for existing algorithms and fast implementation of new algorithms. Our results will promote utilization of combinatorial techniques and will impact research in many scientific computing applications, some of which are listed
1 edition published in 2003 in English and held by 5 WorldCat member libraries worldwide
Combinatorial algorithms have long played an important role in many applications of scientific computing such as sparse matrix computations and parallel computing. The growing importance of combinatorial algorithms in emerging applications like computational biology and scientific data mining calls for development of a high performance library for combinatorial algorithms. Building such a library requires a new structure for combinatorial algorithms research that enables fast implementation of new algorithms. We propose a structure for combinatorial algorithms research that mimics the research structure of numerical algorithms. Numerical algorithms research is nicely complemented with high performance libraries, and this can be attributed to the fact that there are only a small number of fundamental problems that underlie numerical solvers. Furthermore there are only a handful of kernels that enable implementation of algorithms for these fundamental problems. Building a similar structure for combinatorial algorithms will enable efficient implementations for existing algorithms and fast implementation of new algorithms. Our results will promote utilization of combinatorial techniques and will impact research in many scientific computing applications, some of which are listed
Reconfigurable Hybrid Interconnection for Static and DynamicScientific Applications(
)
1 edition published in 2006 in English and held by 5 WorldCat member libraries worldwide
As we enter the era of petascale computing, system architects must plan for machines composed of tens of thousands or even hundreds of thousands of processors. Although fully connected networks such as fattree interconnects currently dominate HPC network designs, such approaches are inadequate for thousands of processors due to the superlinear growth of component costs. Traditional lowdegree interconnect topologies, such as the 3D torus, have reemerged as a competitive solution because the number of switch components scales linearly with the node count, but such networks are poorly suited for the requirements of many scientific applications. We present our latest work on a hybrid switch architecture called HFAST that uses circuit switches to dynamically reconfigure a lowerdegree interconnect to suit the topological requirements of each scientific application. This paper expands upon our prior work on the requirements of nonadaptive applications by analyzing the communication characteristics of dynamically adapting AMR code and presents a methodology that captures the evolving communication requirements. We also present a new optimization that computes the underutilization of fattree interconnects for a given communication topology, showing the potential of constructing a ''fittree'' for the application by using the HFAST circuit switches to provision an optimal interconnect topology for each application. Finally, we apply our new optimization technique to the communication requirements of the AMR code to demonstrate the potential of using dynamic reconfiguration of the HFAST interconnect between the communication intensive phases of a dynamically adapting application
1 edition published in 2006 in English and held by 5 WorldCat member libraries worldwide
As we enter the era of petascale computing, system architects must plan for machines composed of tens of thousands or even hundreds of thousands of processors. Although fully connected networks such as fattree interconnects currently dominate HPC network designs, such approaches are inadequate for thousands of processors due to the superlinear growth of component costs. Traditional lowdegree interconnect topologies, such as the 3D torus, have reemerged as a competitive solution because the number of switch components scales linearly with the node count, but such networks are poorly suited for the requirements of many scientific applications. We present our latest work on a hybrid switch architecture called HFAST that uses circuit switches to dynamically reconfigure a lowerdegree interconnect to suit the topological requirements of each scientific application. This paper expands upon our prior work on the requirements of nonadaptive applications by analyzing the communication characteristics of dynamically adapting AMR code and presents a methodology that captures the evolving communication requirements. We also present a new optimization that computes the underutilization of fattree interconnects for a given communication topology, showing the potential of constructing a ''fittree'' for the application by using the HFAST circuit switches to provision an optimal interconnect topology for each application. Finally, we apply our new optimization technique to the communication requirements of the AMR code to demonstrate the potential of using dynamic reconfiguration of the HFAST interconnect between the communication intensive phases of a dynamically adapting application
Computing Criticality of Lines in Power Systems(
)
1 edition published in 2006 in English and held by 5 WorldCat member libraries worldwide
We propose a computationally efficient method based onnonlinear optimization to identify critical lines, failure of which cancause severe blackouts. Our method computes criticality measure for alllines at a time, as opposed to detecting a single vulnerability, providing a global view of the system. This information on criticality oflines can be used to identify multiple contingencies by selectivelyexploring multiple combinations of broken lines. The effectiveness of ourmethod is demonstrated on the IEEE 30 and 118 bus systems, where we canvery quickly detect the most critical lines in the system and identifysevere multiple contingencies
1 edition published in 2006 in English and held by 5 WorldCat member libraries worldwide
We propose a computationally efficient method based onnonlinear optimization to identify critical lines, failure of which cancause severe blackouts. Our method computes criticality measure for alllines at a time, as opposed to detecting a single vulnerability, providing a global view of the system. This information on criticality oflines can be used to identify multiple contingencies by selectivelyexploring multiple combinations of broken lines. The effectiveness of ourmethod is demonstrated on the IEEE 30 and 118 bus systems, where we canvery quickly detect the most critical lines in the system and identifysevere multiple contingencies
Power system extreme event screening using graphpartitioning(
)
1 edition published in 2006 in English and held by 5 WorldCat member libraries worldwide
We propose a partitioning problem in a power system contextthat weighs the two objectives of minimizing cuts between partitions andmaximizing the power imbalance between partitions. We then pose theproblem in a purely graph theoretic sense. We offer an approximatesolution through relaxation of the integer problem and suggest refinementusing stochastic methods. Results are presented for the IEEE 30bus and118bus electric power systems
1 edition published in 2006 in English and held by 5 WorldCat member libraries worldwide
We propose a partitioning problem in a power system contextthat weighs the two objectives of minimizing cuts between partitions andmaximizing the power imbalance between partitions. We then pose theproblem in a purely graph theoretic sense. We offer an approximatesolution through relaxation of the integer problem and suggest refinementusing stochastic methods. Results are presented for the IEEE 30bus and118bus electric power systems
A divideandconquer algorithm for identifying strongly connectedcomponents(
)
1 edition published in 2003 in English and held by 5 WorldCat member libraries worldwide
Strongly connected components of a directed graph can be found in an optimal linear time, by algorithms based on depth first search. Unfortunately, depth first search is difficult to parallelize. We describe two divideandconquer algorithms for this problem that have significantly greater potential for parallelization. We show the expected serial runtime of our simpler algorithm to be O(m log n), for a graph with n vertices and m edges. We then show that the second algorithm has O(mlog n) worstcase complexity
1 edition published in 2003 in English and held by 5 WorldCat member libraries worldwide
Strongly connected components of a directed graph can be found in an optimal linear time, by algorithms based on depth first search. Unfortunately, depth first search is difficult to parallelize. We describe two divideandconquer algorithms for this problem that have significantly greater potential for parallelization. We show the expected serial runtime of our simpler algorithm to be O(m log n), for a graph with n vertices and m edges. We then show that the second algorithm has O(mlog n) worstcase complexity
The Inhibiting Bisection Problem(
)
1 edition published in 2006 in English and held by 5 WorldCat member libraries worldwide
Given a graph where each vertex is assigned a generation orconsumption volume, we try to bisect the graph so that each part has asignificant generation/consumption mismatch, and the cutsize of thebisection is small. Our motivation comes from the vulnerability analysisof distribution systems such as the electric power system. We show thatthe constrained version of the problem, where we place either the cutsizeor the mismatch significance as a constraint and optimize the other, isNPcomplete, and provide an integer programming formulation. We alsopropose an alternative relaxed formulation, which can tradeoff betweenthe two objectives and show that the alternative formulation of theproblem can be solved in polynomial time by a maximum flow solver. Ourexperiments with benchmark electric power systems validate theeffectiveness of our methods
1 edition published in 2006 in English and held by 5 WorldCat member libraries worldwide
Given a graph where each vertex is assigned a generation orconsumption volume, we try to bisect the graph so that each part has asignificant generation/consumption mismatch, and the cutsize of thebisection is small. Our motivation comes from the vulnerability analysisof distribution systems such as the electric power system. We show thatthe constrained version of the problem, where we place either the cutsizeor the mismatch significance as a constraint and optimize the other, isNPcomplete, and provide an integer programming formulation. We alsopropose an alternative relaxed formulation, which can tradeoff betweenthe two objectives and show that the alternative formulation of theproblem can be solved in polynomial time by a maximum flow solver. Ourexperiments with benchmark electric power systems validate theeffectiveness of our methods
Compressing bitmap indices by data reorganization(
)
1 edition published in 2004 in English and held by 4 WorldCat member libraries worldwide
Many scientific applications generate massive volumes of data through observations or computer simulations, bringing up the need for effective indexing methods for efficient storage and retrieval of scientific data. Unlike conventional databases, scientific data is mostly readonly and its volume can reach to the order of petabytes, making a compact index structure vital. Bit map indexing has been successfully applied to scientific databases by exploiting the fact that scientific data are enumerated or numerical. Bitmap indices can be compressed with variants of run length encoding for a compact index structure. However even this may not be enough for the enormous data generated in some applications such as high energy physics. In this paper, we study how to reorganize bitmap tables for improved compression rates. Our algorithms are used just as a preprocessing step, thus there is no need to revise the current indexing techniques and the query processing algorithms. We introduce the tuple reordering problem, which aims to reorganize database tuples for optimal compression rates. We propose Gray code ordering algorithm for this NPComplete problem, which is an inplace algorithm, and runs in linear time in the order of the size of the database. We also discuss how the tuple reordering problem can be reduced to the traveling salesperson problem. Our experimental results on real data sets show that the compression ratio can be improved by a factor of 4 to 7
1 edition published in 2004 in English and held by 4 WorldCat member libraries worldwide
Many scientific applications generate massive volumes of data through observations or computer simulations, bringing up the need for effective indexing methods for efficient storage and retrieval of scientific data. Unlike conventional databases, scientific data is mostly readonly and its volume can reach to the order of petabytes, making a compact index structure vital. Bit map indexing has been successfully applied to scientific databases by exploiting the fact that scientific data are enumerated or numerical. Bitmap indices can be compressed with variants of run length encoding for a compact index structure. However even this may not be enough for the enormous data generated in some applications such as high energy physics. In this paper, we study how to reorganize bitmap tables for improved compression rates. Our algorithms are used just as a preprocessing step, thus there is no need to revise the current indexing techniques and the query processing algorithms. We introduce the tuple reordering problem, which aims to reorganize database tuples for optimal compression rates. We propose Gray code ordering algorithm for this NPComplete problem, which is an inplace algorithm, and runs in linear time in the order of the size of the database. We also discuss how the tuple reordering problem can be reduced to the traveling salesperson problem. Our experimental results on real data sets show that the compression ratio can be improved by a factor of 4 to 7
Sevgili Murat : an instructional course in modern Turkish(
Visual
)
1 edition published in 2004 in Turkish and held by 4 WorldCat member libraries worldwide
This program is intended to allow students of Turkish to listen to and observe a variety of communicative situations in a natural setting, while at the same time seeing and hearing images and sounds of life in Turkey. It follows the story of Murat, a 29year old man who has been raised in the United States by his Turkish father and American mother. After his father dies, Murat finds his father's diary that he kept as a young man. Murat decides to go to Turkey to retrace his father's footsteps; this leads him throughout Istanbul and into southern Turkey
1 edition published in 2004 in Turkish and held by 4 WorldCat member libraries worldwide
This program is intended to allow students of Turkish to listen to and observe a variety of communicative situations in a natural setting, while at the same time seeing and hearing images and sounds of life in Turkey. It follows the story of Murat, a 29year old man who has been raised in the United States by his Turkish father and American mother. After his father dies, Murat finds his father's diary that he kept as a young man. Murat decides to go to Turkey to retrace his father's footsteps; this leads him throughout Istanbul and into southern Turkey
Combinatorial algorithms in scientific computing by
Ali Pınar(
)
2 editions published in 2001 in English and held by 3 WorldCat member libraries worldwide
This thesis covers six combinatorial problems relevant to various problems in scientific computing. The problems were motivated by different scientific computing applications, and the solution techniques used fundamental methods of computer science. We reported both theoretical and practical results for these problems. Our work included complexity analysis and design and analysis of algorithms, as well as implementation and empirical studies
2 editions published in 2001 in English and held by 3 WorldCat member libraries worldwide
This thesis covers six combinatorial problems relevant to various problems in scientific computing. The problems were motivated by different scientific computing applications, and the solution techniques used fundamental methods of computer science. We reported both theoretical and practical results for these problems. Our work included complexity analysis and design and analysis of algorithms, as well as implementation and empirical studies
RetSynth: determining all optimal and suboptimal synthetic pathways that facilitate synthesis of target compounds in chassis
organisms by Leanne S Whitmore(
)
1 edition published in 2019 in English and held by 2 WorldCat member libraries worldwide
1 edition published in 2019 in English and held by 2 WorldCat member libraries worldwide
Special issue "The next Marmara earthquake: disaster mitigation, recovery, and early warning" by
Takane Hori(
)
1 edition published in 2017 in English and held by 2 WorldCat member libraries worldwide
1 edition published in 2017 in English and held by 2 WorldCat member libraries worldwide
Frictional strength of North Anatolian fault in eastern Marmara region by
Ali Pınar(
)
1 edition published in 2016 in English and held by 2 WorldCat member libraries worldwide
1 edition published in 2016 in English and held by 2 WorldCat member libraries worldwide
Chanceconstrained economic dispatch with renewable energy and storage by
Jianqiang Cheng(
)
1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide
1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide
Contingencyconstrained unit commitment with postcontingency corrective recourse by Richard LiYang Chen(
)
1 edition published in 2014 in English and held by 2 WorldCat member libraries worldwide
1 edition published in 2014 in English and held by 2 WorldCat member libraries worldwide
Physically based probabilistic seismic hazard analysis using broadband ground motion simulation: a case study for the Prince
Islands Fault, Marmara Sea by Aydin Mert(
)
1 edition published in 2016 in English and held by 2 WorldCat member libraries worldwide
1 edition published in 2016 in English and held by 2 WorldCat member libraries worldwide
OneDimensional Partitioning for Heterogeneous Systems: Theory and Practice by
Ali Pınar(
)
1 edition published in 2008 in Undetermined and held by 1 WorldCat member library worldwide
We study the problem of onedimensional partitioning of nonuniform workload arrays with optimal load balancing for heterogeneous systems. We look at two cases: chainonchain partitioning, where the order of the processors is specified, and chain partitioning, where processor permutation is allowed. We present polynomial time algorithms to solve the chainonchain partitioning problem optimally, while we prove that the chain partition is NPcomplete. Our empirical studies show that our proposed exact algorithms produce substantially better results than heuristics while the solution times remain comparable
1 edition published in 2008 in Undetermined and held by 1 WorldCat member library worldwide
We study the problem of onedimensional partitioning of nonuniform workload arrays with optimal load balancing for heterogeneous systems. We look at two cases: chainonchain partitioning, where the order of the processors is specified, and chain partitioning, where processor permutation is allowed. We present polynomial time algorithms to solve the chainonchain partitioning problem optimally, while we prove that the chain partition is NPcomplete. Our empirical studies show that our proposed exact algorithms produce substantially better results than heuristics while the solution times remain comparable
Computing Criticality of Lines in Power Systems by
Ali Pınar(
)
1 edition published in 2006 in Undetermined and held by 1 WorldCat member library worldwide
We propose a computationally efficient method based on nonlinear optimization to identify critical lines, failure of which can cause severe blackouts. Our method computes criticality measure for all lines at a time, as opposed to detecting a single vulnerability, providing a global view of the system. This information on criticality of lines can be used to identify multiple contingencies by selectively exploring multiple combinations of broken lines. The effectiveness of our method is demonstrated on the IEEE 30 and 118 bus systems, where we can very quickly detect the most critical lines in the system and identify severe multiple contingencies
1 edition published in 2006 in Undetermined and held by 1 WorldCat member library worldwide
We propose a computationally efficient method based on nonlinear optimization to identify critical lines, failure of which can cause severe blackouts. Our method computes criticality measure for all lines at a time, as opposed to detecting a single vulnerability, providing a global view of the system. This information on criticality of lines can be used to identify multiple contingencies by selectively exploring multiple combinations of broken lines. The effectiveness of our method is demonstrated on the IEEE 30 and 118 bus systems, where we can very quickly detect the most critical lines in the system and identify severe multiple contingencies
The Inhibiting Bisection Problem by
Ali Pınar(
)
1 edition published in 2006 in Undetermined and held by 1 WorldCat member library worldwide
Given a graph where each vertex is assigned a generation or consumption volume, we try to bisect the graph so that each part has a significant generation/consumption mismatch, and the cutsize of the bisection is small. Our motivation comes from the vulnerability analysis of distribution systems such as the electric power system. We show that the constrained version of the problem, where we place either the cutsize or the mismatch significance as a constraint and optimize the other, is NPcomplete, and provide an integer programming formulation. We also propose an alternative relaxed formulation, which can tradeoff between the two objectives and show that the alternative formulation of the problem can be solved in polynomial time by a maximum flow solver. Our experiments with benchmark electric power systems validate the effectiveness of our methods
1 edition published in 2006 in Undetermined and held by 1 WorldCat member library worldwide
Given a graph where each vertex is assigned a generation or consumption volume, we try to bisect the graph so that each part has a significant generation/consumption mismatch, and the cutsize of the bisection is small. Our motivation comes from the vulnerability analysis of distribution systems such as the electric power system. We show that the constrained version of the problem, where we place either the cutsize or the mismatch significance as a constraint and optimize the other, is NPcomplete, and provide an integer programming formulation. We also propose an alternative relaxed formulation, which can tradeoff between the two objectives and show that the alternative formulation of the problem can be solved in polynomial time by a maximum flow solver. Our experiments with benchmark electric power systems validate the effectiveness of our methods
Combinatorial Algorithms for Computing Column Space Bases That Have Sparse Inverses by
Ali Pınar(
)
1 edition published in 2005 in Undetermined and held by 1 WorldCat member library worldwide
This paper presents a combinatorial study on the problem of constructing a sparse basis forthe nullspace of a sparse, under determined, full rank matrix, A. Such a nullspace is suitable for solving solving many saddle point problems. Our approach is to form a column space basis of A that has a sparse inverse, by selecting suitable columns of A. This basis is then used to form a sparse nullspace basis in fundamental form. We investigate three different algorithms for computing the column space basis: Two greedy approaches that rely on matching, and a third employing a divide and conquer strategy implemented with hypergraph partitioning followed by the greedy approach. We also discuss the complexity of selecting a column basis when it is known that a block diagonal basis exists with a small given block size
1 edition published in 2005 in Undetermined and held by 1 WorldCat member library worldwide
This paper presents a combinatorial study on the problem of constructing a sparse basis forthe nullspace of a sparse, under determined, full rank matrix, A. Such a nullspace is suitable for solving solving many saddle point problems. Our approach is to form a column space basis of A that has a sparse inverse, by selecting suitable columns of A. This basis is then used to form a sparse nullspace basis in fundamental form. We investigate three different algorithms for computing the column space basis: Two greedy approaches that rely on matching, and a third employing a divide and conquer strategy implemented with hypergraph partitioning followed by the greedy approach. We also discuss the complexity of selecting a column basis when it is known that a block diagonal basis exists with a small given block size
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Related Identities
 United States Department of Energy Office of Scientific and Technical Information Distributor
 Lawrence Berkeley National Laboratory Researcher
 SpringerLink (Online service) Other
 Koloğlu, Deniz
 Ersel, Hasan
 Rey, Cemal Reşit 19041985
 Lesieutre, Bernard
 USDOE Director. Office of Science. Office of AdvancedScientific Computing Research Sponsor
 Donde, Vaibhav
 Lijewski, Michael
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