Albert Zomaya | The University of Sydney (original) (raw)

Papers by Albert Zomaya

Quantifying and comparing the scientific output of researchers has become critical for government... more Quantifying and comparing the scientific output of researchers has become critical for governments , funding agencies and universities. Comparison by reputation and direct assessment of contributions to the field is no longer possible, as the number of scientists increases and traditional definitions about scientific fields become blurred. The h-index is often used for comparing scientists, but has several well-documented shortcomings. In this paper, we introduce a new index for measuring and comparing the publication records of scientists: the pagerank-index (symbolised as π). The index uses a version of pagerank algorithm and the citation networks of papers in its computation, and is fundamentally different from the existing variants of h-index because it considers not only the number of citations but also the actual impact of each citation. We adapt two approaches to demonstrate the utility of the new index. Firstly, we use a simulation model of a community of authors, whereby we create various 'groups' of authors which are different from each other in inherent publication habits, to show that the pagerank-index is fairer than the existing indices in three distinct scenarios: (i) when authors try to 'massage' their index by publishing papers in low-quality outlets primarily to self-cite other papers (ii) when authors collaborate in large groups in order to obtain more authorships (iii) when authors spend most of their time in producing genuine but low quality publications that would massage their index. Secondly, we undertake two real world case studies: (i) the evolving author community of quantum game theory, as defined by Google Scholar (ii) a snapshot of the high energy physics (HEP) theory research community in arXiv. In both case studies, we find that the list of top authors vary very significantly when h-index and pagerank-index are used for comparison. We show that in both cases, authors who have collaborated in large groups and/or published less impactful papers tend to be comparatively favoured by the h-index, whereas the pagerank-index highlights authors who have made a relatively small number of definitive contributions, or written papers which served to highlight the link between diverse disciplines, or typically worked in smaller

The indices currently used by scholarly databases, such as Google scholar, to rank scientists, do... more The indices currently used by scholarly databases, such as Google scholar, to rank scientists, do not attach weights to the citations. Neither is the underlying network structure of citations considered in computing these metrics. This results in scientists cited by well-recognized journals not being rewarded, and may lead to potential misuse if documents are created purely to cite others. In this paper we introduce a new ranking metric, the p-index (pagerank-index), which is computed from the underlying citation network of papers, and uses the pagerank algorithm in its computation. The index is a percentile score, and can potentially be implemented in public databases such as Google scholar, and can be applied at many levels of abstraction. We demonstrate that the metric aids in fairer ranking of scientists compared to h-index and its variants. We do this by simulating a realistic model of the evolution of citation and collaboration networks in a particular field, and comparing h-index and p-index of scientists under a number of scenarios. Our results show that the p-index is immune to author behaviors that can result in artificially bloated h-index values.

Abstract We present an approach to designing cellular automata-based multiprocessor scheduling al... more Abstract We present an approach to designing cellular automata-based multiprocessor scheduling algorithms in which extracting knowledge about the scheduling process occurs. We consider the simplest case when a multiprocessor system is limited to two-processors. To design cellular automata corresponding to a given program graph, we propose a generic definition of program graph neighborhood, transparent to the various kinds, sizes, and shapes of program graphs.

Abstract Over the past decades, caching has become the key technology used for bridging the perfo... more Abstract Over the past decades, caching has become the key technology used for bridging the performance gap across memory hierarchies via temporal or spatial localities; in particular, the effect is prominent in disk storage systems. Applications that involve heavy I/O activities, which are common in the cloud, probably benefit the most from caching.

Abstract This paper presents a novel competitive-based approach, called BestMap, to simultaneousl... more Abstract This paper presents a novel competitive-based approach, called BestMap, to simultaneously schedule jobs and assign data files to different entities of a Grid system. Using two independent, however collaborating mechanisms, schedulers of the system allocate jobs and data files to computational and storage nodes to minimize the overall makespan as well as the overall delivery time of all data files to their dependant jobs, respectively.

Abstract We propose an efficient reconfigurable parallel prefix counting network based on the rec... more Abstract We propose an efficient reconfigurable parallel prefix counting network based on the recently-proposed technique of shift switching with domino logic, where the charge/discharge signals propagate along the switch chain producing semaphores results in a network that is fast and highly hardware-compact. The proposed architecture for prefix counting N-1 bits features a total delay of (4 log N+√ N-2)* T d, where T d is the delay for charging or discharging a row of two prefix sum units of eight shift switches.

Ethernet switches in them is becoming a critical issue. Most existing energy saving approaches us... more Ethernet switches in them is becoming a critical issue. Most existing energy saving approaches use a centralized methodology that assumes global knowledge of data center networks. Though these approaches can achieve nearly optimal energy saving for static traffic patterns, they are not suitable when the traffic patterns can change rapidly or the data centers have a large size.

A “book-embedding” of a graph G comprises embedding the graph's nodes along the spine of a book a... more A “book-embedding” of a graph G comprises embedding the graph's nodes along the spine of a book and embedding the edges on the pages so that the edges embedded on the same page do not intersect. This is also referred to as the page model. The “pagenumber” of a graph is the thickness of the smallest (in number of pages) book into which G can be embedded. The problem has been studied only for some specific kind of graphs.

In the last decade, we have been witnessing an explosive growth in the development, deployment, a... more In the last decade, we have been witnessing an explosive growth in the development, deployment, and adoption of a wide range of wireless communication technologies and applications. Ubiquitous access of information anywhere, anytime, from any device by end-users continues to drive the need to develop innovative design architectures, protocols, and networks with capabilities that can help achieve this goal.

A visual, interdisciplinary approach to solving problems in numerical methods Computing for Numer... more A visual, interdisciplinary approach to solving problems in numerical methods Computing for Numerical Methods Using Visual C++ fills the need for a complete, authoritative book on the visual solutions to problems in numerical methods using C++.

Abstract We show that the notoriously difficult problem of finding and reporting the smallest num... more Abstract We show that the notoriously difficult problem of finding and reporting the smallest number of vertex-disjoint paths that cover the vertices of a graph can be solved time-and work-optimally for cographs. Our algorithm solves this problem in O (log n) time using n/log n processors on the EREW-PRAM for an n-vertex cograph G represented by its cotree

The incremental and dynamic construction of interconnection networks from smaller components ofte... more The incremental and dynamic construction of interconnection networks from smaller components often leaves the fundamental problem of assigning addresses to processors to be contended with at power-up time. The problem is fundamental, for virtually all parallel algorithms known to the authors assume that the processors know their global coordinates within the newly created entity. We refer to this problem as the initialization problem. Rather surprisingly, the initialization problem has not received much attention in the literature.

Abstract The paper presents new results concerning application of cellular automata (CA) to secre... more Abstract The paper presents new results concerning application of cellular automata (CA) to secret key cryptography extending results presented in Tomassini and Perrenoud (2000), and Tomassini and Sipper (2000). One dimensional, nonuniform CA is considered as a generator of pseudorandom number sequences (PNS) used in cryptography with the secret key. The quality of PNS highly depends on a set of applied CA rules. To find such rules nonuniform CA with two types of rules is considered.

Abstract: In this paper, we propose an analytical method to model the dependency between configur... more Abstract: In this paper, we propose an analytical method to model the dependency between configuration parameters and total execution time of Map-Reduce applications. Our approach has three key phases: profiling, modeling, and prediction. In profiling, an application is run several times with different sets of MapReduce configuration parameters to profile the execution time of the application on a given platform.

Abstract We address the problem of designing efficient and scalable hardware-algorithms for compu... more Abstract We address the problem of designing efficient and scalable hardware-algorithms for computing the sum and prefix sums of aw k-bit,(k⩾ 2), sequence using as basic building blocks linear arrays of at most w 2 shift switches, where w is a small power of 2. An immediate consequence of this feature is that in our designs broadcasts are limited to buses of length at most w 2. We adopt a VLSI delay model where the “length” of a bus is proportional with the number of devices on the bus.

SUMMARY In this paper, we study CPU utilization time patterns of several MapReduce applications. ... more SUMMARY In this paper, we study CPU utilization time patterns of several MapReduce applications. After extracting running patterns of several applications, the patterns along with their statistical information are saved in a reference database to be later used to tweak system parameters to efficiently execute future unknown applications.

Quantifying and comparing the scientific output of researchers has become critical for government... more Quantifying and comparing the scientific output of researchers has become critical for governments , funding agencies and universities. Comparison by reputation and direct assessment of contributions to the field is no longer possible, as the number of scientists increases and traditional definitions about scientific fields become blurred. The h-index is often used for comparing scientists, but has several well-documented shortcomings. In this paper, we introduce a new index for measuring and comparing the publication records of scientists: the pagerank-index (symbolised as π). The index uses a version of pagerank algorithm and the citation networks of papers in its computation, and is fundamentally different from the existing variants of h-index because it considers not only the number of citations but also the actual impact of each citation. We adapt two approaches to demonstrate the utility of the new index. Firstly, we use a simulation model of a community of authors, whereby we create various 'groups' of authors which are different from each other in inherent publication habits, to show that the pagerank-index is fairer than the existing indices in three distinct scenarios: (i) when authors try to 'massage' their index by publishing papers in low-quality outlets primarily to self-cite other papers (ii) when authors collaborate in large groups in order to obtain more authorships (iii) when authors spend most of their time in producing genuine but low quality publications that would massage their index. Secondly, we undertake two real world case studies: (i) the evolving author community of quantum game theory, as defined by Google Scholar (ii) a snapshot of the high energy physics (HEP) theory research community in arXiv. In both case studies, we find that the list of top authors vary very significantly when h-index and pagerank-index are used for comparison. We show that in both cases, authors who have collaborated in large groups and/or published less impactful papers tend to be comparatively favoured by the h-index, whereas the pagerank-index highlights authors who have made a relatively small number of definitive contributions, or written papers which served to highlight the link between diverse disciplines, or typically worked in smaller

The indices currently used by scholarly databases, such as Google scholar, to rank scientists, do... more The indices currently used by scholarly databases, such as Google scholar, to rank scientists, do not attach weights to the citations. Neither is the underlying network structure of citations considered in computing these metrics. This results in scientists cited by well-recognized journals not being rewarded, and may lead to potential misuse if documents are created purely to cite others. In this paper we introduce a new ranking metric, the p-index (pagerank-index), which is computed from the underlying citation network of papers, and uses the pagerank algorithm in its computation. The index is a percentile score, and can potentially be implemented in public databases such as Google scholar, and can be applied at many levels of abstraction. We demonstrate that the metric aids in fairer ranking of scientists compared to h-index and its variants. We do this by simulating a realistic model of the evolution of citation and collaboration networks in a particular field, and comparing h-index and p-index of scientists under a number of scenarios. Our results show that the p-index is immune to author behaviors that can result in artificially bloated h-index values.

Abstract We present an approach to designing cellular automata-based multiprocessor scheduling al... more Abstract We present an approach to designing cellular automata-based multiprocessor scheduling algorithms in which extracting knowledge about the scheduling process occurs. We consider the simplest case when a multiprocessor system is limited to two-processors. To design cellular automata corresponding to a given program graph, we propose a generic definition of program graph neighborhood, transparent to the various kinds, sizes, and shapes of program graphs.

Abstract Over the past decades, caching has become the key technology used for bridging the perfo... more Abstract Over the past decades, caching has become the key technology used for bridging the performance gap across memory hierarchies via temporal or spatial localities; in particular, the effect is prominent in disk storage systems. Applications that involve heavy I/O activities, which are common in the cloud, probably benefit the most from caching.

Abstract This paper presents a novel competitive-based approach, called BestMap, to simultaneousl... more Abstract This paper presents a novel competitive-based approach, called BestMap, to simultaneously schedule jobs and assign data files to different entities of a Grid system. Using two independent, however collaborating mechanisms, schedulers of the system allocate jobs and data files to computational and storage nodes to minimize the overall makespan as well as the overall delivery time of all data files to their dependant jobs, respectively.

Abstract We propose an efficient reconfigurable parallel prefix counting network based on the rec... more Abstract We propose an efficient reconfigurable parallel prefix counting network based on the recently-proposed technique of shift switching with domino logic, where the charge/discharge signals propagate along the switch chain producing semaphores results in a network that is fast and highly hardware-compact. The proposed architecture for prefix counting N-1 bits features a total delay of (4 log N+√ N-2)* T d, where T d is the delay for charging or discharging a row of two prefix sum units of eight shift switches.

Ethernet switches in them is becoming a critical issue. Most existing energy saving approaches us... more Ethernet switches in them is becoming a critical issue. Most existing energy saving approaches use a centralized methodology that assumes global knowledge of data center networks. Though these approaches can achieve nearly optimal energy saving for static traffic patterns, they are not suitable when the traffic patterns can change rapidly or the data centers have a large size.

A “book-embedding” of a graph G comprises embedding the graph's nodes along the spine of a book a... more A “book-embedding” of a graph G comprises embedding the graph's nodes along the spine of a book and embedding the edges on the pages so that the edges embedded on the same page do not intersect. This is also referred to as the page model. The “pagenumber” of a graph is the thickness of the smallest (in number of pages) book into which G can be embedded. The problem has been studied only for some specific kind of graphs.

In the last decade, we have been witnessing an explosive growth in the development, deployment, a... more In the last decade, we have been witnessing an explosive growth in the development, deployment, and adoption of a wide range of wireless communication technologies and applications. Ubiquitous access of information anywhere, anytime, from any device by end-users continues to drive the need to develop innovative design architectures, protocols, and networks with capabilities that can help achieve this goal.

A visual, interdisciplinary approach to solving problems in numerical methods Computing for Numer... more A visual, interdisciplinary approach to solving problems in numerical methods Computing for Numerical Methods Using Visual C++ fills the need for a complete, authoritative book on the visual solutions to problems in numerical methods using C++.

Abstract We show that the notoriously difficult problem of finding and reporting the smallest num... more Abstract We show that the notoriously difficult problem of finding and reporting the smallest number of vertex-disjoint paths that cover the vertices of a graph can be solved time-and work-optimally for cographs. Our algorithm solves this problem in O (log n) time using n/log n processors on the EREW-PRAM for an n-vertex cograph G represented by its cotree

The incremental and dynamic construction of interconnection networks from smaller components ofte... more The incremental and dynamic construction of interconnection networks from smaller components often leaves the fundamental problem of assigning addresses to processors to be contended with at power-up time. The problem is fundamental, for virtually all parallel algorithms known to the authors assume that the processors know their global coordinates within the newly created entity. We refer to this problem as the initialization problem. Rather surprisingly, the initialization problem has not received much attention in the literature.

Abstract The paper presents new results concerning application of cellular automata (CA) to secre... more Abstract The paper presents new results concerning application of cellular automata (CA) to secret key cryptography extending results presented in Tomassini and Perrenoud (2000), and Tomassini and Sipper (2000). One dimensional, nonuniform CA is considered as a generator of pseudorandom number sequences (PNS) used in cryptography with the secret key. The quality of PNS highly depends on a set of applied CA rules. To find such rules nonuniform CA with two types of rules is considered.

Abstract: In this paper, we propose an analytical method to model the dependency between configur... more Abstract: In this paper, we propose an analytical method to model the dependency between configuration parameters and total execution time of Map-Reduce applications. Our approach has three key phases: profiling, modeling, and prediction. In profiling, an application is run several times with different sets of MapReduce configuration parameters to profile the execution time of the application on a given platform.

Abstract We address the problem of designing efficient and scalable hardware-algorithms for compu... more Abstract We address the problem of designing efficient and scalable hardware-algorithms for computing the sum and prefix sums of aw k-bit,(k⩾ 2), sequence using as basic building blocks linear arrays of at most w 2 shift switches, where w is a small power of 2. An immediate consequence of this feature is that in our designs broadcasts are limited to buses of length at most w 2. We adopt a VLSI delay model where the “length” of a bus is proportional with the number of devices on the bus.

SUMMARY In this paper, we study CPU utilization time patterns of several MapReduce applications. ... more SUMMARY In this paper, we study CPU utilization time patterns of several MapReduce applications. After extracting running patterns of several applications, the patterns along with their statistical information are saved in a reference database to be later used to tweak system parameters to efficiently execute future unknown applications.