This dissertation has two complementary focuses. First, it provides a solution to large scale rea... more This dissertation has two complementary focuses. First, it provides a solution to large scale real-time system air traffic Control (ATC) using an enhanced SIMD machine model called an associative processor (AP). The second is the comparison of this implementation with a multiprocessor implementation and the implications of these comparisons. This paper demonstrates how one application, ATC, can more easily, more simply, and more efficiently be implemented on an AP than is generally possible on other types of traditional hardware. The AP implementation of ATC will take advantage of its deterministic hardware to use static scheduling. Our solution differs from previous ATC systems that are designed for MIMD computers and have a great deal of difficulty meeting the predictability requirements for ATC, which are critical for meeting the strict certification standards required for safety critical software components. The proposed AP solution supports accurate predictions of worst case ex...
Proceedings 15th International Parallel and Distributed Processing Symposium. IPDPS 2001
This paper describes a new and different paradigm for real-time command and control that we show ... more This paper describes a new and different paradigm for real-time command and control that we show can provide a static, polynomial-time scheduling algorithm. Current efforts in real-time scheduling have been unable to predict system performance, and use a unpredictable "dynamic" scheduling algorithm. The Nation's Air Traffic Control (ATC) System has been unable to satisfy performance requirements, and is extremely expensive. An editorial in "USA Today" (4-19-1999) cites expenditures in ATC at $41 billion. But, current multiprocessor technology cannot do the job. The FAA wisely required a "proof of concept" study before the (AAS) contract. But that study, after expending a billion dollars, was abandoned, and production moved forward. AAS was canceled in 1995 exactly in line with real-time scheduling theory predictions. Garey, Graham, and Johnson state: "For these scheduling problems, no efficient optimization algorithm has yet been found, and indeed, none is expected."[9]. Stankovic et. al. state: "…complexity results show most real-time multiprocessing scheduling is NP-hard." [6]. We offer a completely different approach, that has been shown to overcome the severe limitations of multiprocessing. Additionally, we show that real-time parallel-processing techniques can be statically scheduled to solve the set of tasks making up the ATC problem for a worst-case environment.
Proceedings International Parallel and Distributed Processing Symposium
An object oriented description and framework of the Multiple ASsociative Computing (MASC) model o... more An object oriented description and framework of the Multiple ASsociative Computing (MASC) model of parallel computation is presented. This description identifies MASC objects and specifies various object and inter-object relationships, dependencies, and behaviors. This was achieved by describing various views of the MASC model by using many of the UML structural and behavioral diagrams. This object oriented framework has been highly useful in designing an implementation of a runtime environment for the MASC model. Also the object oriented framework has been highly effective for further parallel modeling techniques, comparisons to other parallel models, MASC parallel system software research, and MASC algorithm development.
Proceedings 16th International Parallel and Distributed Processing Symposium, 2002
SIMDs and MIMDs are the most important categories of computer systems for parallel computing in F... more SIMDs and MIMDs are the most important categories of computer systems for parallel computing in Flynn's classification scheme. Due to their higher flexibility in allowing processors to execute independently and their ability to use off-the-shelf microprocessors, the MIMD systems are generally favored and considered to be more powerful. In comparison, the SIMD systems are considered outdated. However, we observe that many intrinsic weaknesses of the MIMD systems are not fully recognized until they are compared while solving realtime scheduling problems. The SIMD systems have inherent advantages that MIMDs lack. In this paper, we compare SIMDs and MIMDs in real-time scheduling, e.g., scheduling for air traffic control. Two abstract parallel computation models, the ASC and BSP models that represent SIMDs and MIMDs respectively, are used in our discussion and analysis. We argue that the common belief that MIMDs have greater power than SIMDs is false. Our research shows that SIMDs are not outdated, as they offer tractable solutions for problems considered intractable with MIMDs. Rather, SIMDs are more efficient and powerful in some important application fields. They deserve more attention and considerations than they currently receive.
Proceedings International Parallel and Distributed Processing Symposium
In this paper, SIMD and MIMD solutions for the realtime database management problem of air traffi... more In this paper, SIMD and MIMD solutions for the realtime database management problem of air traffic control are compared. A real-time database system is highly constrained in a multiprocessor and access to the common database must be made to a limited number of data elements at a time. This MIMD database access is contrasted with the comparable SIMD common database access, which can be several hundred times greater. This is true because the SIMD can simultaneously access thousands of pertinent records instead of the limited number in the MIMD. A relatively simple example is given of a problem that has a polynomial time solution using a SIMD but for which a polynomial time solution using a MIMD is normally impossible. The fact that SIMDs can support a polynomial time solution for the Air Traffic Control problem but this problem is normally considered to be intractable for multiprocessors argues against the common belief that MIMDs have greater power than SIMDs. SIMDs are more efficient and powerful for some critically important application areas.
The Multiple Associative Computing (MASC) parallel model is a generalization model of an Associat... more The Multiple Associative Computing (MASC) parallel model is a generalization model of an Associative Computing (ASC) parallel model designed to support multiple ASC data parallel threads by using control parallelism. The MASC model is designed to combine the advantages of both Single Instruction Stream Multiple Data Streams (SIMD) and Multiple Instruction Streams Multiple Data Streams (MIMD) models. Here is the first time that a complete description of MASC model has been implemented (in software) true to its original description. A cycle precision simulator is built to demonstrate the performance of MASC on various multithreaded algorithms. The simulator is a software prototype for the model with sufficient software details to allow it to be converted into a hardware prototype of the model. If a reasonable limit for the number of threads simultaneously supported is assumed, the resulting hardware design is not only easily to implement, but can easily support a huge number of proces...
2010 IEEE International Symposium on Parallel & Distributed Processing, Workshops and Phd Forum (IPDPSW), 2010
This paper proposes a SIMD solution to air traffic control (ATC) using an enhanced SIMD machine m... more This paper proposes a SIMD solution to air traffic control (ATC) using an enhanced SIMD machine model called an Associative Processor (AP). This differs from previous ATC systems that are designed for MIMD computers and have a great deal of difficulty meeting the predictability requirements for ATC, which are critical for meeting the strict certification standards required for safety critical software components. The proposed SIMD solution will support accurate and meaningful predictions of worst case execution times and will guarantee all deadlines are met. Also, the software will be much simpler and smaller in size than the current corresponding ATC software. An important consequence of these features is that the V&V (Validation and Verification) process will be considerably simpler than for current ATC software. Additionally, the associative processor is enhanced SIMD hardware and is considerably cheaper and simpler than the MIMD hardware currently used to support ATC. The ClearSpeed CSX600 accelerator is used to emulate the AP model. A preliminary implementation of the proposed method has been developed and experimental results comparing MIMD and CSX600 approaches are presented. The performance of CSX600 has better scalability, efficiency, and predictability than that of MIMD.
Proceedings. 1998 International Conference on Parallel Processing (Cat. No.98EX205)
The ASC MSIMD model for parallel computation supports a generalized version of an associative sty... more The ASC MSIMD model for parallel computation supports a generalized version of an associative style of computing that has been used since the introduction of associative SIMD computers in the early 1970's. In particular, this model supports data parallelism, constant time maximum and minimum operations, one or more instruction streams ISs which are sent to an equal number of partition sets of processors, assignment of tasks to the ISs using control parallelism. ASC also allows a network to interconnect the processing elements PEs. This paper shows how ASC can be simulated with synchronous PRAM, and the converse. These results provide an important step in de ning the power of associative model in terms of PRAM which is the most well studied parallel model. Also, these simulations will provide numerous algorithms for ASC by providing an automatic method o f c onverting algorithms from PRAM to ASC.
2007 IEEE International Parallel and Distributed Processing Symposium, 2007
The MASC model is a multi-SIMD model that uses control parallelism to coordinate the interaction ... more The MASC model is a multi-SIMD model that uses control parallelism to coordinate the interaction of data parallel threads. It supports a generalized associative style of parallel computation. The power of this model has been compared to that of priority CRCW PRAM and enhanced meshes. In this paper, we present the work on simulations between MASC and reconfigurable bus-based models, in particular, different versions of the Reconfigurable Multiple Bus Machine (RMBM). It is shown that MASC and the Basic RMBM (B-RMBM) can simulate each other in constant time if the number of buses on the B-RMBM is (j) where j is the number of MASC instruction streams. Thus, when these two models satisfy the preceding condition, they have the same power. Simulations of other stronger versions of RMBM using MASC are also considered. Since the RMBM model has been shown to be as powerful as a general Reconfigurable Mesh (RM), our simulations can be used to establish a relationship between MASC and RM. As RM has been widely accepted as an extremely powerful model, our work gives a better understanding of the MASC model and provides useful information concerning its power.
Proceedings 15th International Parallel and Distributed Processing Symposium. IPDPS 2001
The MASC (Multiple Associative Computing) model is a generalized associative-style computational ... more The MASC (Multiple Associative Computing) model is a generalized associative-style computational model that naturally supports massive data-parallelism and also control-parallelism. A wide range of applications has been developed on this model. Recent research has compared its power to the power of other popular parallel models such as the PRAM and MMB models using simulations. However, the simulation of MMB has identified some important issues regarding the cost of certain basic MASC operations required for associative computing such as broadcasts, reductions, and associative searches. This paper investigates these issues and gives background information and an analysis of timings for these operations, based on implementation techniques and comparison fairness with respect to other models. It aims to provide justification and clarify arguments on the timings for these constant-time or nearly constant-time basic MASC operations.
2012 IEEE 26th International Parallel and Distributed Processing Symposium Workshops & PhD Forum, 2012
This paper proposes a solution to air traffic control (ATC) using an enhanced SIMD machine model ... more This paper proposes a solution to air traffic control (ATC) using an enhanced SIMD machine model called an Associative Processor (AP). Our solution differs from previous ATC systems that are designed for MIMD computers and have a great deal of difficulty meeting the predictability requirements for ATC, which are critical for meeting the strict certification standards required for safety critical software components. The proposed AP solution supports accurate predictions of worst case execution times and guarantees all deadlines are met. Furthermore, the software developed based on the AP model is much simpler and smaller in size than the current corresponding ATC software. As the associative processor is built from SIMD hardware, it is considerably cheaper and simpler than the MIMD hardware currently used to support ATC. We have designed a prototype for eight ATC real-time tasks on ClearSpeed CSX600 accelerator that is used to emulate AP. Performance is evaluated in terms of execution time and predictability and is compared to the fastest host-only version implemented using OpenMP on an 8core multiprocessor (MIMD). Our extensive experiments show that the AP implementation meets all deadlines that can be statically scheduled. To the contrary, some tasks miss their deadlines when implemented on MIMD. It is shown that the proposed AP solution will support accurate and meaningful predictions of worst case execution times and will guarantee that all deadlines are met.
Proceedings 16th International Parallel and Distributed Processing Symposium, 2002
This paper presents a new static and dynamic recursive parallel algorithm for the convex hull pro... more This paper presents a new static and dynamic recursive parallel algorithm for the convex hull problem. This algorithm is a parallel adaptation of the Graham Scan and Quick Hull algorithms. The computational model selected for this algorithm is the associative computing model (ASC) which supports massive parallelism through the use of data parallelism and constant time associative search and maximum functions. Also, ASC can be supported on existing SIMD computers. The static algorithm requires O(n) space, O(log n) average case running time, and O(n) worst case running time. If O(log n) ISs are used the, static algorithm should have an average running time of O(log log n).
2008 IEEE International Symposium on Parallel and Distributed Processing, 2008
One of the most commonly used tools by computational biologists is some form of sequence alignmen... more One of the most commonly used tools by computational biologists is some form of sequence alignment. Heuristic alignment algorithms developed for speed and their multiple results such as BLAST [1] and FASTA [2] are not a total replacement for the more rigorous but slower algorithms like Smith-Waterman [3]. The different techniques complement one another. A heuristic can filter dissimilar sequences from a large database such as GenBank [4] and the Smith-Waterman algorithm performs more detailed, in-depth alignment in a way not adequately handled by heuristic methods. An associative parallel Smith-Waterman algorithm has been improved and further parallelized. Analysis between different algorithms, different types of file input, and different input sizes have been performed and are reported here. The newly developed associative algorithm reduces the running time for rigorous pairwise local sequence alignment.
Journal of Parallel and Distributed Computing, 2010
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit:
Journal of Parallel and Distributed Computing, 2013
This paper has two complementary focuses. The first is the system design and algorithmic developm... more This paper has two complementary focuses. The first is the system design and algorithmic development for air traffic control (ATC) using an associative SIMD processor (AP). The second is the comparison of this implementation with a multiprocessor implementation and the implications of these comparisons. This paper demonstrates how one application, ATC, can more easily, more simply, and more efficiently be implemented on an AP than is generally possible on other types of traditional hardware. The AP implementation of ATC will take advantage of its deterministic hardware to use static scheduling. The software will be dramatically smaller and cheaper to create and maintain. Likewise, a large AP system will be considerably simpler and cheaper than the MIMD hardware currently used. While APs were used for ATC-type applications earlier, these are no longer available. We use a Clear-Speed CSX600 accelerator to emulate the AP solutions of ATC on an ATC prototype consisting of eight data-intensive ATC real-time tasks. Its performance is compared with an 8-core multiprocessor (MP) using OpenMP. Our extensive experiments show that the AP implementation meets all deadlines while the MP will regularly miss a large number of deadlines. The AP code will be similar in size to sequential code for the same tasks and will avoid all of the additional support software needed with an MP to handle dynamic scheduling, load balancing, shared resource management, race conditions,
In this paper, we describe and implement compiler extension for a parallel computer language call... more In this paper, we describe and implement compiler extension for a parallel computer language called Associative Computing (ASC) language to support multiple instruction streams in a Multiple Associative Computing (MASC) model using manager-worker paradigm. A user directed ...
AbstractThis paper proposes a solution to air traffic control (ATC) using an enhanced SIMD machi... more AbstractThis paper proposes a solution to air traffic control (ATC) using an enhanced SIMD machine model called an Associative Processor (AP). This differs from previous ATC systems that are designed for MIMD computers and have a great deal of difficulty meeting the ...
Proc. of the 1999 Midwest Workshop on Parallel …, 1999
MASC (for Multiple Associative Computing) is a practical, highly scalable joint control parallel,... more MASC (for Multiple Associative Computing) is a practical, highly scalable joint control parallel, data parallel model that naturally supports massive parallelism and a wide range of applications. In this paper, we propose efficient algorithms for the MASC model with a 2-D mesh to simulate enhanced meshes, e.g., meshes with multiple broadcasting (MMB), and basic reconfigurable meshes (BRM). The results not only show the power of the MASC model in terms of the enhanced mesh models but also provide an automatic conversion of numerous algorithms designed for enhanced meshes to the MASC model.
This dissertation has two complementary focuses. First, it provides a solution to large scale rea... more This dissertation has two complementary focuses. First, it provides a solution to large scale real-time system air traffic Control (ATC) using an enhanced SIMD machine model called an associative processor (AP). The second is the comparison of this implementation with a multiprocessor implementation and the implications of these comparisons. This paper demonstrates how one application, ATC, can more easily, more simply, and more efficiently be implemented on an AP than is generally possible on other types of traditional hardware. The AP implementation of ATC will take advantage of its deterministic hardware to use static scheduling. Our solution differs from previous ATC systems that are designed for MIMD computers and have a great deal of difficulty meeting the predictability requirements for ATC, which are critical for meeting the strict certification standards required for safety critical software components. The proposed AP solution supports accurate predictions of worst case ex...
Proceedings 15th International Parallel and Distributed Processing Symposium. IPDPS 2001
This paper describes a new and different paradigm for real-time command and control that we show ... more This paper describes a new and different paradigm for real-time command and control that we show can provide a static, polynomial-time scheduling algorithm. Current efforts in real-time scheduling have been unable to predict system performance, and use a unpredictable "dynamic" scheduling algorithm. The Nation's Air Traffic Control (ATC) System has been unable to satisfy performance requirements, and is extremely expensive. An editorial in "USA Today" (4-19-1999) cites expenditures in ATC at $41 billion. But, current multiprocessor technology cannot do the job. The FAA wisely required a "proof of concept" study before the (AAS) contract. But that study, after expending a billion dollars, was abandoned, and production moved forward. AAS was canceled in 1995 exactly in line with real-time scheduling theory predictions. Garey, Graham, and Johnson state: "For these scheduling problems, no efficient optimization algorithm has yet been found, and indeed, none is expected."[9]. Stankovic et. al. state: "…complexity results show most real-time multiprocessing scheduling is NP-hard." [6]. We offer a completely different approach, that has been shown to overcome the severe limitations of multiprocessing. Additionally, we show that real-time parallel-processing techniques can be statically scheduled to solve the set of tasks making up the ATC problem for a worst-case environment.
Proceedings International Parallel and Distributed Processing Symposium
An object oriented description and framework of the Multiple ASsociative Computing (MASC) model o... more An object oriented description and framework of the Multiple ASsociative Computing (MASC) model of parallel computation is presented. This description identifies MASC objects and specifies various object and inter-object relationships, dependencies, and behaviors. This was achieved by describing various views of the MASC model by using many of the UML structural and behavioral diagrams. This object oriented framework has been highly useful in designing an implementation of a runtime environment for the MASC model. Also the object oriented framework has been highly effective for further parallel modeling techniques, comparisons to other parallel models, MASC parallel system software research, and MASC algorithm development.
Proceedings 16th International Parallel and Distributed Processing Symposium, 2002
SIMDs and MIMDs are the most important categories of computer systems for parallel computing in F... more SIMDs and MIMDs are the most important categories of computer systems for parallel computing in Flynn's classification scheme. Due to their higher flexibility in allowing processors to execute independently and their ability to use off-the-shelf microprocessors, the MIMD systems are generally favored and considered to be more powerful. In comparison, the SIMD systems are considered outdated. However, we observe that many intrinsic weaknesses of the MIMD systems are not fully recognized until they are compared while solving realtime scheduling problems. The SIMD systems have inherent advantages that MIMDs lack. In this paper, we compare SIMDs and MIMDs in real-time scheduling, e.g., scheduling for air traffic control. Two abstract parallel computation models, the ASC and BSP models that represent SIMDs and MIMDs respectively, are used in our discussion and analysis. We argue that the common belief that MIMDs have greater power than SIMDs is false. Our research shows that SIMDs are not outdated, as they offer tractable solutions for problems considered intractable with MIMDs. Rather, SIMDs are more efficient and powerful in some important application fields. They deserve more attention and considerations than they currently receive.
Proceedings International Parallel and Distributed Processing Symposium
In this paper, SIMD and MIMD solutions for the realtime database management problem of air traffi... more In this paper, SIMD and MIMD solutions for the realtime database management problem of air traffic control are compared. A real-time database system is highly constrained in a multiprocessor and access to the common database must be made to a limited number of data elements at a time. This MIMD database access is contrasted with the comparable SIMD common database access, which can be several hundred times greater. This is true because the SIMD can simultaneously access thousands of pertinent records instead of the limited number in the MIMD. A relatively simple example is given of a problem that has a polynomial time solution using a SIMD but for which a polynomial time solution using a MIMD is normally impossible. The fact that SIMDs can support a polynomial time solution for the Air Traffic Control problem but this problem is normally considered to be intractable for multiprocessors argues against the common belief that MIMDs have greater power than SIMDs. SIMDs are more efficient and powerful for some critically important application areas.
The Multiple Associative Computing (MASC) parallel model is a generalization model of an Associat... more The Multiple Associative Computing (MASC) parallel model is a generalization model of an Associative Computing (ASC) parallel model designed to support multiple ASC data parallel threads by using control parallelism. The MASC model is designed to combine the advantages of both Single Instruction Stream Multiple Data Streams (SIMD) and Multiple Instruction Streams Multiple Data Streams (MIMD) models. Here is the first time that a complete description of MASC model has been implemented (in software) true to its original description. A cycle precision simulator is built to demonstrate the performance of MASC on various multithreaded algorithms. The simulator is a software prototype for the model with sufficient software details to allow it to be converted into a hardware prototype of the model. If a reasonable limit for the number of threads simultaneously supported is assumed, the resulting hardware design is not only easily to implement, but can easily support a huge number of proces...
2010 IEEE International Symposium on Parallel & Distributed Processing, Workshops and Phd Forum (IPDPSW), 2010
This paper proposes a SIMD solution to air traffic control (ATC) using an enhanced SIMD machine m... more This paper proposes a SIMD solution to air traffic control (ATC) using an enhanced SIMD machine model called an Associative Processor (AP). This differs from previous ATC systems that are designed for MIMD computers and have a great deal of difficulty meeting the predictability requirements for ATC, which are critical for meeting the strict certification standards required for safety critical software components. The proposed SIMD solution will support accurate and meaningful predictions of worst case execution times and will guarantee all deadlines are met. Also, the software will be much simpler and smaller in size than the current corresponding ATC software. An important consequence of these features is that the V&V (Validation and Verification) process will be considerably simpler than for current ATC software. Additionally, the associative processor is enhanced SIMD hardware and is considerably cheaper and simpler than the MIMD hardware currently used to support ATC. The ClearSpeed CSX600 accelerator is used to emulate the AP model. A preliminary implementation of the proposed method has been developed and experimental results comparing MIMD and CSX600 approaches are presented. The performance of CSX600 has better scalability, efficiency, and predictability than that of MIMD.
Proceedings. 1998 International Conference on Parallel Processing (Cat. No.98EX205)
The ASC MSIMD model for parallel computation supports a generalized version of an associative sty... more The ASC MSIMD model for parallel computation supports a generalized version of an associative style of computing that has been used since the introduction of associative SIMD computers in the early 1970's. In particular, this model supports data parallelism, constant time maximum and minimum operations, one or more instruction streams ISs which are sent to an equal number of partition sets of processors, assignment of tasks to the ISs using control parallelism. ASC also allows a network to interconnect the processing elements PEs. This paper shows how ASC can be simulated with synchronous PRAM, and the converse. These results provide an important step in de ning the power of associative model in terms of PRAM which is the most well studied parallel model. Also, these simulations will provide numerous algorithms for ASC by providing an automatic method o f c onverting algorithms from PRAM to ASC.
2007 IEEE International Parallel and Distributed Processing Symposium, 2007
The MASC model is a multi-SIMD model that uses control parallelism to coordinate the interaction ... more The MASC model is a multi-SIMD model that uses control parallelism to coordinate the interaction of data parallel threads. It supports a generalized associative style of parallel computation. The power of this model has been compared to that of priority CRCW PRAM and enhanced meshes. In this paper, we present the work on simulations between MASC and reconfigurable bus-based models, in particular, different versions of the Reconfigurable Multiple Bus Machine (RMBM). It is shown that MASC and the Basic RMBM (B-RMBM) can simulate each other in constant time if the number of buses on the B-RMBM is (j) where j is the number of MASC instruction streams. Thus, when these two models satisfy the preceding condition, they have the same power. Simulations of other stronger versions of RMBM using MASC are also considered. Since the RMBM model has been shown to be as powerful as a general Reconfigurable Mesh (RM), our simulations can be used to establish a relationship between MASC and RM. As RM has been widely accepted as an extremely powerful model, our work gives a better understanding of the MASC model and provides useful information concerning its power.
Proceedings 15th International Parallel and Distributed Processing Symposium. IPDPS 2001
The MASC (Multiple Associative Computing) model is a generalized associative-style computational ... more The MASC (Multiple Associative Computing) model is a generalized associative-style computational model that naturally supports massive data-parallelism and also control-parallelism. A wide range of applications has been developed on this model. Recent research has compared its power to the power of other popular parallel models such as the PRAM and MMB models using simulations. However, the simulation of MMB has identified some important issues regarding the cost of certain basic MASC operations required for associative computing such as broadcasts, reductions, and associative searches. This paper investigates these issues and gives background information and an analysis of timings for these operations, based on implementation techniques and comparison fairness with respect to other models. It aims to provide justification and clarify arguments on the timings for these constant-time or nearly constant-time basic MASC operations.
2012 IEEE 26th International Parallel and Distributed Processing Symposium Workshops & PhD Forum, 2012
This paper proposes a solution to air traffic control (ATC) using an enhanced SIMD machine model ... more This paper proposes a solution to air traffic control (ATC) using an enhanced SIMD machine model called an Associative Processor (AP). Our solution differs from previous ATC systems that are designed for MIMD computers and have a great deal of difficulty meeting the predictability requirements for ATC, which are critical for meeting the strict certification standards required for safety critical software components. The proposed AP solution supports accurate predictions of worst case execution times and guarantees all deadlines are met. Furthermore, the software developed based on the AP model is much simpler and smaller in size than the current corresponding ATC software. As the associative processor is built from SIMD hardware, it is considerably cheaper and simpler than the MIMD hardware currently used to support ATC. We have designed a prototype for eight ATC real-time tasks on ClearSpeed CSX600 accelerator that is used to emulate AP. Performance is evaluated in terms of execution time and predictability and is compared to the fastest host-only version implemented using OpenMP on an 8core multiprocessor (MIMD). Our extensive experiments show that the AP implementation meets all deadlines that can be statically scheduled. To the contrary, some tasks miss their deadlines when implemented on MIMD. It is shown that the proposed AP solution will support accurate and meaningful predictions of worst case execution times and will guarantee that all deadlines are met.
Proceedings 16th International Parallel and Distributed Processing Symposium, 2002
This paper presents a new static and dynamic recursive parallel algorithm for the convex hull pro... more This paper presents a new static and dynamic recursive parallel algorithm for the convex hull problem. This algorithm is a parallel adaptation of the Graham Scan and Quick Hull algorithms. The computational model selected for this algorithm is the associative computing model (ASC) which supports massive parallelism through the use of data parallelism and constant time associative search and maximum functions. Also, ASC can be supported on existing SIMD computers. The static algorithm requires O(n) space, O(log n) average case running time, and O(n) worst case running time. If O(log n) ISs are used the, static algorithm should have an average running time of O(log log n).
2008 IEEE International Symposium on Parallel and Distributed Processing, 2008
One of the most commonly used tools by computational biologists is some form of sequence alignmen... more One of the most commonly used tools by computational biologists is some form of sequence alignment. Heuristic alignment algorithms developed for speed and their multiple results such as BLAST [1] and FASTA [2] are not a total replacement for the more rigorous but slower algorithms like Smith-Waterman [3]. The different techniques complement one another. A heuristic can filter dissimilar sequences from a large database such as GenBank [4] and the Smith-Waterman algorithm performs more detailed, in-depth alignment in a way not adequately handled by heuristic methods. An associative parallel Smith-Waterman algorithm has been improved and further parallelized. Analysis between different algorithms, different types of file input, and different input sizes have been performed and are reported here. The newly developed associative algorithm reduces the running time for rigorous pairwise local sequence alignment.
Journal of Parallel and Distributed Computing, 2010
This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit:
Journal of Parallel and Distributed Computing, 2013
This paper has two complementary focuses. The first is the system design and algorithmic developm... more This paper has two complementary focuses. The first is the system design and algorithmic development for air traffic control (ATC) using an associative SIMD processor (AP). The second is the comparison of this implementation with a multiprocessor implementation and the implications of these comparisons. This paper demonstrates how one application, ATC, can more easily, more simply, and more efficiently be implemented on an AP than is generally possible on other types of traditional hardware. The AP implementation of ATC will take advantage of its deterministic hardware to use static scheduling. The software will be dramatically smaller and cheaper to create and maintain. Likewise, a large AP system will be considerably simpler and cheaper than the MIMD hardware currently used. While APs were used for ATC-type applications earlier, these are no longer available. We use a Clear-Speed CSX600 accelerator to emulate the AP solutions of ATC on an ATC prototype consisting of eight data-intensive ATC real-time tasks. Its performance is compared with an 8-core multiprocessor (MP) using OpenMP. Our extensive experiments show that the AP implementation meets all deadlines while the MP will regularly miss a large number of deadlines. The AP code will be similar in size to sequential code for the same tasks and will avoid all of the additional support software needed with an MP to handle dynamic scheduling, load balancing, shared resource management, race conditions,
In this paper, we describe and implement compiler extension for a parallel computer language call... more In this paper, we describe and implement compiler extension for a parallel computer language called Associative Computing (ASC) language to support multiple instruction streams in a Multiple Associative Computing (MASC) model using manager-worker paradigm. A user directed ...
AbstractThis paper proposes a solution to air traffic control (ATC) using an enhanced SIMD machi... more AbstractThis paper proposes a solution to air traffic control (ATC) using an enhanced SIMD machine model called an Associative Processor (AP). This differs from previous ATC systems that are designed for MIMD computers and have a great deal of difficulty meeting the ...
Proc. of the 1999 Midwest Workshop on Parallel …, 1999
MASC (for Multiple Associative Computing) is a practical, highly scalable joint control parallel,... more MASC (for Multiple Associative Computing) is a practical, highly scalable joint control parallel, data parallel model that naturally supports massive parallelism and a wide range of applications. In this paper, we propose efficient algorithms for the MASC model with a 2-D mesh to simulate enhanced meshes, e.g., meshes with multiple broadcasting (MMB), and basic reconfigurable meshes (BRM). The results not only show the power of the MASC model in terms of the enhanced mesh models but also provide an automatic conversion of numerous algorithms designed for enhanced meshes to the MASC model.
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