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Proceedings of the International Conference on Computational and Mathematical Methods in Science ... more Proceedings of the International Conference on Computational and Mathematical Methods in Science and Engineering, CMMSE 2008 13–17 June 2008. CsegGraph: A Graph Coloring Instance Generator in Sparse Derivative Matrix Determination Shahadat Hossain1 1 Department of ...

Computations involving sparse and structured matrices arise frequently in problems in operations ... more Computations involving sparse and structured matrices arise frequently in problems in operations research, science and engineering. Exploiting this structure has been a major contributor to the efficient application of past and current computing platforms, and will continue to play an important role for next-generation systems.

ABSTRACT We describe a branch-and-bound approach for determining a sparse Jacobian matrix A # Rm×... more ABSTRACT We describe a branch-and-bound approach for determining a sparse Jacobian matrix A # Rm×n using an extended notion of structural independence or structural orthogonality of segments of columns of A or AT .We assume that the sparsity pattern of the sparse Jacobian is a priori known. Our branching strategy is based on Zykov contraction algorithm [8].

ABSTRACT We describe a substitution based sparse Jacobian matrix determination method using algor... more ABSTRACT We describe a substitution based sparse Jacobian matrix determination method using algorithmic differentiation. Utilizing the a priori known sparsity pattern, a compression scheme is determined using graph coloring. The "compressed pattern" of the Jacobian matrix is then reordered into a form suitable for computation by substitution. We show that the column reordering of the compressed pattern matrix (so as to align the zero entries into consecutive locations in each row) can be viewed as a variant of traveling salesman problem. Preliminary computational results show that on the test problems the performance of nearest-neighbor type heuristic algorithms is highly encouraging.

... within a bacterium to create intraclonal heterogeneity. 4 In addition P. aeruginosa has a pro... more ... within a bacterium to create intraclonal heterogeneity. 4 In addition P. aeruginosa has a propensity to develop mutations in genes important for DNA-mismatch repair (MMR). These strains, sometimes referred to as “hypermutator ...

Large-scale combinatorial scientific computing problems arising in sparse or otherwise structured... more Large-scale combinatorial scientific computing problems arising in sparse or otherwise structured matrix computation are often expressed using an appropriate graph model, and sometimes the same problem can be given in more than one graph model with similar asymptotic computational complexity. The relative merits of different graph models for the same problem can then be expressed in terms of factors such as generality of the model or ease of computer implementation. We review contemporary graph formulations for largescale sparse Jacobian matrix determination problem (JMDP) and suggest the pattern graph as a unifying framework for methods that exploit sparsity by matrix compression: row compression, column compression, or a combination of the two. We argue that with the pattern graph, which is structurally close to the underlying matrix, exploitable sparsity and structures in the matrix are unlikely to be lost in ''translation'' from a matrix problem to a graph problem. From an algorithmic view point the structural correspondence between the matrix and its graph, as we demonstrate in this paper, leads to a better exposition of the compression heuristics and their efficient computer realization. Array-based data structures are suggested as the basic building-blocks for the efficient implementation of relevant graph algorithms. Results from the numerical testing of a subset of implemented algorithms on a suite of test instances drawn from the standard test matrix collection are presented.

ABSTRACT Numerical linear algebra is an essential ingredient in algorithms for solving problems i... more ABSTRACT Numerical linear algebra is an essential ingredient in algorithms for solving problems in optimization, nonlinear equations, and differential equations. Spanning diverse application areas, from economic planning to complex network analysis, modeling and solving problems arising in those areas share a common theme: numerical calculations on matrices that are sparse or structured or both. Linear algebraic calculations involving sparse matrices of order 109 are now routine. In this article, we give an overview of scientific calculations where effective utilization of properties such as sparsity, problem structure, etc. play a vital role and where the linear algebraic calculations are much more complex than their dense counterpart. This is partly because operation and storage involving known zeros must be avoided, and partly because the fact that modern computing hardware may not be amenable to the specialized techniques needed for sparse problems. We focus on sparse calculations arising in nonlinear equation solving using the Newton method. For further resources related to this article, please visit the WIREs website. Conflict of interest: The authors have declared no conflicts of interest for this article.

A total of 5.0 km rural roads have been constructed using Jute Geotextiles (JGT) as field trials ... more A total of 5.0 km rural roads have been constructed using Jute Geotextiles (JGT) as field trials in different geophysical locations of Bangladesh. The project sites were so selected that subgrade California Bearing Ratio (CBR) values of more than 3.0% were not achievable without adopting special means. On top of subgrade, first, an Improved Subgrade (ISG) layer of 75 mm compacted sand is placed. Right above this ISG layer, the specified JGT is laid with proper overlapping and pegging. After this, another layer of ISG is placed. The rest of construction of pavement follows usual practice of placing a sub-base layer followed by a base layer and black top. A series of monitoring and performance evaluation has been undertaken at different time intervals by obtaining field CBR values along the same road sections to evaluate the efficacy of JGT. The test results reveal that the load carrying capacity of the road sections increases from 1.5 to 7.0 times due to use of JGT over a range of time interval. It is hypothesized that load carrying capacity of JGT reinforced subgrades increases through three different mechanisms: membrane action of JGT until it decomposes, absorption of moisture from subgrade by JGT resulting in an increased dry density of subgrade and consolidation of subgrade due to surcharge load of ISG, sub-base and base layer along with a percentage of traffic load. It may be noted that the economic benefit and durability enhancement of the rural roads constructed using JGT are the obvious consequences.

Water gypsy usually known as Bede or Bedey is a nomadic racial community of Bangladesh ancestrall... more Water gypsy usually known as Bede or Bedey is a nomadic racial community of Bangladesh ancestrally lives, travels and earns their livings on the river. Generally they live on a flat platform alongside of river. But residing in the boat is their inherited tradition. Majority of the Bedes rely on snake related trading, lucky heathers and also sell herbal medicines for their livelihoods support. Neglecting hundreds of hostilities of nature they come out in search of their livings. As they mainly resided in the boat and embankment of the river and also waterways is the main communication system therefore they get easily affected by devastating cyclone. The coastal bedes' perception, prediction and survival strategies against cyclone are area of interest in this paper. The aims of the study are to find out the perception and prediction indicators used by the Bede people during cyclones; examine their survival strategies at the face and pace of cyclones; assess the problems they frequently face for being a marginalized group of the society; and highlight important findings that can be used by the disaster management programmers/ planners of NGOs and GO line agencies. The study mostly relied upon qualitative data and information with the close accordance of objectives. Relevant information on the concerned issue has been collected through in-depth, key informant interviews and group discussions with the Bede people were also carried out. Primary data and information collected through questionnaire have been summarized and analysed for the purpose of the study. The key finding of the study includes survival strategies and relies upon cumulative experience of the earlier generations are the structural adjustment to reduce cyclone damage, specific forms of housing; and the prediction of cyclones using the state and level of the river-water, wind direction, weather, behaviour of some living organisms; the problems they mainly face are poor house structure, nonexistence of proper education, don't get informed cyclone warning signals just in time, even don't know the exact location of cyclone shelter, absence of pure drinking water, don't have the right to vote, lack of support from GO's and NGO's and they don't get space in policy making decisions. The interrelationships of all the problems related to cyclone disaster mitigation are so complex that needs an integrated approach. One of the objectives of this paper is to make suggestions to increase the effectiveness of the counter measures in the future, incorporating the indigenous knowledge of cyclone prediction and disaster management.

In Bangladesh, located on the extensive flood plains of the Ganges and Brahmaputra Rivers floodin... more In Bangladesh, located on the extensive flood plains of the Ganges and Brahmaputra Rivers flooding is a natural part of life. Thus water logging in the urban area is not a new problem. It's a part of life but the frequency of this problem is increasing. The urban area has been experiencing water logging for the last few years even a little rain causes a serious problem for certain areas. Increased urban development's not providing sufficient drainage results in water logging leaving parts of urban area inundated for several days. This causes naturally large infrastructural problems for the city. Most of the time during the monsoon, the water level of the river remains higher than the terrain inside the urban area. Hence, standard draining by gravity may not always be possible. It has been identified that improvement of the drainage system is one of the highest priority needs of the urban authority for living environment of its urban population. The urban area suffers from drainage congestions and water logging especially during rainy season. It creates an unhealthy environmental situation and causes inconvenience to the residents of the urban including damages to the infrastructure, loss of business and spreading of diseases. It is observed that there is a lack of planned and adequate drainage network system in the Teknaf, a small urban area of southern part of Bangladesh beside the Bay of Bengal. The developed technology can easily be transferred and applied to catchment areas experiencing similar problems.

Proceedings of the International Conference on Computational and Mathematical Methods in Science ... more Proceedings of the International Conference on Computational and Mathematical Methods in Science and Engineering, CMMSE 2008 13–17 June 2008. CsegGraph: A Graph Coloring Instance Generator in Sparse Derivative Matrix Determination Shahadat Hossain1 1 Department of ...

Computations involving sparse and structured matrices arise frequently in problems in operations ... more Computations involving sparse and structured matrices arise frequently in problems in operations research, science and engineering. Exploiting this structure has been a major contributor to the efficient application of past and current computing platforms, and will continue to play an important role for next-generation systems.

ABSTRACT We describe a branch-and-bound approach for determining a sparse Jacobian matrix A # Rm×... more ABSTRACT We describe a branch-and-bound approach for determining a sparse Jacobian matrix A # Rm×n using an extended notion of structural independence or structural orthogonality of segments of columns of A or AT .We assume that the sparsity pattern of the sparse Jacobian is a priori known. Our branching strategy is based on Zykov contraction algorithm [8].

ABSTRACT We describe a substitution based sparse Jacobian matrix determination method using algor... more ABSTRACT We describe a substitution based sparse Jacobian matrix determination method using algorithmic differentiation. Utilizing the a priori known sparsity pattern, a compression scheme is determined using graph coloring. The "compressed pattern" of the Jacobian matrix is then reordered into a form suitable for computation by substitution. We show that the column reordering of the compressed pattern matrix (so as to align the zero entries into consecutive locations in each row) can be viewed as a variant of traveling salesman problem. Preliminary computational results show that on the test problems the performance of nearest-neighbor type heuristic algorithms is highly encouraging.

... within a bacterium to create intraclonal heterogeneity. 4 In addition P. aeruginosa has a pro... more ... within a bacterium to create intraclonal heterogeneity. 4 In addition P. aeruginosa has a propensity to develop mutations in genes important for DNA-mismatch repair (MMR). These strains, sometimes referred to as “hypermutator ...

Large-scale combinatorial scientific computing problems arising in sparse or otherwise structured... more Large-scale combinatorial scientific computing problems arising in sparse or otherwise structured matrix computation are often expressed using an appropriate graph model, and sometimes the same problem can be given in more than one graph model with similar asymptotic computational complexity. The relative merits of different graph models for the same problem can then be expressed in terms of factors such as generality of the model or ease of computer implementation. We review contemporary graph formulations for largescale sparse Jacobian matrix determination problem (JMDP) and suggest the pattern graph as a unifying framework for methods that exploit sparsity by matrix compression: row compression, column compression, or a combination of the two. We argue that with the pattern graph, which is structurally close to the underlying matrix, exploitable sparsity and structures in the matrix are unlikely to be lost in ''translation'' from a matrix problem to a graph problem. From an algorithmic view point the structural correspondence between the matrix and its graph, as we demonstrate in this paper, leads to a better exposition of the compression heuristics and their efficient computer realization. Array-based data structures are suggested as the basic building-blocks for the efficient implementation of relevant graph algorithms. Results from the numerical testing of a subset of implemented algorithms on a suite of test instances drawn from the standard test matrix collection are presented.

ABSTRACT Numerical linear algebra is an essential ingredient in algorithms for solving problems i... more ABSTRACT Numerical linear algebra is an essential ingredient in algorithms for solving problems in optimization, nonlinear equations, and differential equations. Spanning diverse application areas, from economic planning to complex network analysis, modeling and solving problems arising in those areas share a common theme: numerical calculations on matrices that are sparse or structured or both. Linear algebraic calculations involving sparse matrices of order 109 are now routine. In this article, we give an overview of scientific calculations where effective utilization of properties such as sparsity, problem structure, etc. play a vital role and where the linear algebraic calculations are much more complex than their dense counterpart. This is partly because operation and storage involving known zeros must be avoided, and partly because the fact that modern computing hardware may not be amenable to the specialized techniques needed for sparse problems. We focus on sparse calculations arising in nonlinear equation solving using the Newton method. For further resources related to this article, please visit the WIREs website. Conflict of interest: The authors have declared no conflicts of interest for this article.

A total of 5.0 km rural roads have been constructed using Jute Geotextiles (JGT) as field trials ... more A total of 5.0 km rural roads have been constructed using Jute Geotextiles (JGT) as field trials in different geophysical locations of Bangladesh. The project sites were so selected that subgrade California Bearing Ratio (CBR) values of more than 3.0% were not achievable without adopting special means. On top of subgrade, first, an Improved Subgrade (ISG) layer of 75 mm compacted sand is placed. Right above this ISG layer, the specified JGT is laid with proper overlapping and pegging. After this, another layer of ISG is placed. The rest of construction of pavement follows usual practice of placing a sub-base layer followed by a base layer and black top. A series of monitoring and performance evaluation has been undertaken at different time intervals by obtaining field CBR values along the same road sections to evaluate the efficacy of JGT. The test results reveal that the load carrying capacity of the road sections increases from 1.5 to 7.0 times due to use of JGT over a range of time interval. It is hypothesized that load carrying capacity of JGT reinforced subgrades increases through three different mechanisms: membrane action of JGT until it decomposes, absorption of moisture from subgrade by JGT resulting in an increased dry density of subgrade and consolidation of subgrade due to surcharge load of ISG, sub-base and base layer along with a percentage of traffic load. It may be noted that the economic benefit and durability enhancement of the rural roads constructed using JGT are the obvious consequences.

Water gypsy usually known as Bede or Bedey is a nomadic racial community of Bangladesh ancestrall... more Water gypsy usually known as Bede or Bedey is a nomadic racial community of Bangladesh ancestrally lives, travels and earns their livings on the river. Generally they live on a flat platform alongside of river. But residing in the boat is their inherited tradition. Majority of the Bedes rely on snake related trading, lucky heathers and also sell herbal medicines for their livelihoods support. Neglecting hundreds of hostilities of nature they come out in search of their livings. As they mainly resided in the boat and embankment of the river and also waterways is the main communication system therefore they get easily affected by devastating cyclone. The coastal bedes' perception, prediction and survival strategies against cyclone are area of interest in this paper. The aims of the study are to find out the perception and prediction indicators used by the Bede people during cyclones; examine their survival strategies at the face and pace of cyclones; assess the problems they frequently face for being a marginalized group of the society; and highlight important findings that can be used by the disaster management programmers/ planners of NGOs and GO line agencies. The study mostly relied upon qualitative data and information with the close accordance of objectives. Relevant information on the concerned issue has been collected through in-depth, key informant interviews and group discussions with the Bede people were also carried out. Primary data and information collected through questionnaire have been summarized and analysed for the purpose of the study. The key finding of the study includes survival strategies and relies upon cumulative experience of the earlier generations are the structural adjustment to reduce cyclone damage, specific forms of housing; and the prediction of cyclones using the state and level of the river-water, wind direction, weather, behaviour of some living organisms; the problems they mainly face are poor house structure, nonexistence of proper education, don't get informed cyclone warning signals just in time, even don't know the exact location of cyclone shelter, absence of pure drinking water, don't have the right to vote, lack of support from GO's and NGO's and they don't get space in policy making decisions. The interrelationships of all the problems related to cyclone disaster mitigation are so complex that needs an integrated approach. One of the objectives of this paper is to make suggestions to increase the effectiveness of the counter measures in the future, incorporating the indigenous knowledge of cyclone prediction and disaster management.

In Bangladesh, located on the extensive flood plains of the Ganges and Brahmaputra Rivers floodin... more In Bangladesh, located on the extensive flood plains of the Ganges and Brahmaputra Rivers flooding is a natural part of life. Thus water logging in the urban area is not a new problem. It's a part of life but the frequency of this problem is increasing. The urban area has been experiencing water logging for the last few years even a little rain causes a serious problem for certain areas. Increased urban development's not providing sufficient drainage results in water logging leaving parts of urban area inundated for several days. This causes naturally large infrastructural problems for the city. Most of the time during the monsoon, the water level of the river remains higher than the terrain inside the urban area. Hence, standard draining by gravity may not always be possible. It has been identified that improvement of the drainage system is one of the highest priority needs of the urban authority for living environment of its urban population. The urban area suffers from drainage congestions and water logging especially during rainy season. It creates an unhealthy environmental situation and causes inconvenience to the residents of the urban including damages to the infrastructure, loss of business and spreading of diseases. It is observed that there is a lack of planned and adequate drainage network system in the Teknaf, a small urban area of southern part of Bangladesh beside the Bay of Bengal. The developed technology can easily be transferred and applied to catchment areas experiencing similar problems.