Dr Sylvan Elhay
Position  Visiting Research Fellow 

Org Unit  School of Computer Science 
sylvan.elhay@adelaide.edu.au  
Mobile  +61 4 1432 9875 
Location 
Floor/Room
1 38
,
Engineering North
,
North Terrace


Research Interests
Research interests: Numerical linear algebra, orthogonal polynomials, quadrature formulae, quadratic inverse eigenvalue problems, water distribution systems, convex optimization.
For more information click here

Publications
October 27, 2018
References
[1] Mengning Qiu, Angus R. Simpson, Sylvan Elhay, and Bradley Alexander. A bridgeblock partitioning algorithm for speeding up analysis of water distribution systems. J. Water Resour. Plann. Manage., 20xx. In review.
[2] Jochen Deuerlein, Olivier Piller, Sylvan Elhay, and Angus R. Simpson. A contentbased active set method for the pressure dependent model of water distribution systems. J. Water Resour. Plann. Manage., 145(1):04018082, 2019. DOI: 10.1061/(ASCE)WR.19435452.0001003.
[3] Mengning Qiu, Bradley Alexander, Angus R. Simpson, and Sylvan Elhay. A software tool for assessing the performance of, and implementing, water distribution system solution methods. Environ. Model. Software, 2019. To appear.
[4] Mengning Qiu, Sylvan Elhay, Angus R. Simpson, and Bradley Alexander. A benchmarking study of water distribution system solution methods. J. Water Resour. Plann. Manage., 2019. To appear.
[5] S. Elhay, J. W. Deuerlein, O. Piller, and A. R. Simpson. Graph partitioning in the analysis of pressure dependent water distribution systems. J. Water Resour. Plann. Manage., 144(4):04018011, 2018. DOI: 10.1061/(ASCE)WR.19435452.0000896.
[6] J. W. Deuerlein, O. Piller, S. Elhay, and A. R. Simpson. Sensitivity analysis of topological subgraph of water distribution networks. Procedia Engineering, 186:252–260, 2017. DOI: 10.1016/j.proeng.2017.03.239.
[7] O. Piller, S. Elhay, J. W. Deuerlein, and A. R. Simpson. On the solvability of the pressure driven hydraulic steadystate equations considering feedbackcontrol devices. In Richard Collins, editor, Computing and Control for the Water Industry 2017. Research Studies Press ltd., 2017. DOI: 10.15131/shef.data.c.3867985.v1.
[8] O. Piller, S. Elhay, J. W. Deuerlein, and A. R. Simpson. Why are line search methods needed for hysdraulic ddm and pdm solvers? In Richard Collins, editor, CCWI 2017  Computing and Control for the Water Industry. Research Studies Press ltd., 2017. DOI: 10.15131/shef.data.c.3867985.v1.
[9] J. W. Deuerlein, S. Elhay, and A. R. Simpson. Fast graph matrix partitioning algorithm for solving the water distribution system equations. J. Water Resour. Plann. Manage., 142(1), 2016. DOI: 10.1061/(ASCE)WR.19435452.0000561, 04015037.
[10] S. Elhay, O. Piller, J. W. Deuerlein, and A. R. Simpson. A robust, rapidly convergent method that solves the water distribution equations for pressure dependent models. J. Water Resour. Plann. Manage., 142(2), 2016. DOI: 10.1061/(ASCE)WR.19435452.0000578.
[11] O. Piller, S. Elhay, J. W. Deuerlein, and A. R. Simpson. Local sensitivity of pressure dependent modeling and demand dependent modeling steadystate solutions to variations in parameters. J. Water Resour. Plann. Manage., 142(2), 2016. DOI: 10.1061/(ASCE)WR.19435452.0000729, 04016074.
[12] A. R. Simpson, S. Elhay, and B. Alexander. Forest—core partitioning algorithm for speeding up the analysis of water distribution systems. J. Water Resour. Plann. Manage., 140(4):435–443, November 2014. DOI: 10.1061/(ASCE)WR.19435452.0000336.
[13] S. Elhay, A. R. Simpson, J. W. Deuerlein, B. Alexander, and W. Schilders. A reformulated cotree flows method competitive with the Global Gradient Algorithm for solving the water distribution system equations. J. Water Resour. Plann. Manage., 140(12), 2014. DOI: 10.1061/(ASCE)WR.19435452.0000431.
[14] S. Elhay and A. R. Simpson. Closure on “Dealing with zero flows in solving the nonlinear equations for water distribution systems”. J. Hydraul. Eng., 139(5):560–562, 2013. DOI: 10.1061/(ASCE)HY.19437900.0000696.
[15] A. R. Simpson and S. Elhay. Closure to “Jacobian matrix for solving water distribution system equations with the DarcyWeisbach headloss model”. J. Hydraul. Eng., 138(11):1001–1002, November 2012. DOI: 10.1061/(ASCE)HY.19437900.0000341.
[16] S. Elhay and A. R. Simpson. Dealing with zero flows in solving the non–linear equations for water distribution systems. J. Hydraul. Eng., 137(10):1216–1224, 2011. DOI:10.1061/(ASCE)HY.19437900.0000411. ISSN: 07339429.
[17] A. R. Simpson and S. Elhay. The Jacobian for solving water distribution system equations with the DarcyWeisbach head loss model. J. Hydraul. Eng., 137(6):696–700, 2011. DOI:10.1061/(ASCE)HY.19437900.0000341. ISSN: 07339429.
[18] A. R. Simpson and S. Elhay. A framework for alternative formulations of the pipe network equations. In 11th Annual Symposium on Water Distribution Systems Analysis. American Society of Civil Engineers, May 2009.
[19] A. R. Simpson and S. Elhay. Improving convergence and dealing with zero flows in solving the nonlinear equations for water distribution systems. Technical report, University of Adelaide, 2009.
[20] A. R. Simpson and S. Elhay. Formulating the water distribution system equations in terms of heads and velocity. In 10th Annual Symposium on Water Distribution Systems Analysis. American Society of Civil Engineers, August 2008.
[21] S. Elhay. Some inverse eigenvalue and pole placement problems for linear and quadratic pencils. In Van Dooren et al, editor, Numerical Linear Algebra in Signals, Systems and Control Lecture Notes in Electrical Engineering. Springer Verlag, 2008.
[22] S. Elhay. Symmetry preserving partial pole assignment for the standard and the generalized eigenvalue problems. In Wayne Read and A. J. Roberts, editors, Proceedings of the 13th Biennial Computational Techniques and Applications Conference, CTAC2006, volume 48 of ANZIAM J., pages C264–C279, July 2007. [online] URLhttp://anziamj.austms.org.au/ojs/index.php/ANZIAMJ/article/view/106 [July 20, 2007].
[23] S. Elhay and Y.M. Ram. Quadratic pencil pole assignment by affine sums. In Jagoda Crawford and A. J. Roberts, editors, Proc. of 11th Computational Techniques and Applications Conference CTAC2003, volume 45, pages C592–C603, Jul 2004. [Online] URLhttp://anziamj.austms.org.au/V45/CTAC2003/Elha [July 4, 2004].
[24] A. Ghosh, J. Mazumdar, and S. Elhay. On the inverse problem of a vibrating membrane of arbitrary shape. Int J Appl Maths & Stats, 2(D04):15–28, 2004.
[25] S. Elhay, G.H. Golub, and Y.M. Ram. On the spectrum of a modified linear pencil. Computers and Maths with Appl., 46:1413–1426, 2003.
[26] S. Elhay and Y.M. Ram. An affine inverse eigenvalue problem. Inverse Problems, 18(2):455–466, 2002.
[27] B.N. Datta, S. Elhay, Y.M. Ram, and D. Sarkissian. Partial eigstructure assignemnt for the quadratic pencil. Journal of Sound and Vibration, 230:101–110, 2000.
[28] Y.M. Ram and S. Elhay. Pole assignment in vibratory systems by multi input control. Journal of Sound Vibration, 230:309–321, 2000.
[29] S. Elhay, G.M.L. Gladwell, G.H. Golub, and Y.M. Ram. On some eignevectoreigenvalue relations. SIAM J. Matrix Anal. Appl., 20(3):563–574, 1999.
[30] Y.M. Ram and S. Elhay. Constructing the shape of a rod from eigenvalues. Communications in Numerical Methods in Engineering, 14(7):597–608, July 1998. ISSN: 10698299.
[31] Y.M. Ram and S. Elhay. An inverse eigenvalue problem for the symmetric positive linear pencil with applications to vibrating system. In A. Gill J. Noye, M. Teubner, editor, Computational Techniques and Applications: CTAC97, pages 561–568. World Scientific, 1998.
[32] B.N. Datta, S. Elhay, and Y.M. Ram. Orthogonality and partial pole assignment for the symmetric definite quadratic pencil. Linear Algebra Appl., 257:29–48, 1997.
[33] A. Torokhti, P. Howlett, S. Elhay, W. Moran, and D. Gray. Data compression with noise suppression: A new approach. In Proc. of the IEEE International Symposium on Information Theory, Ulm, Germany, 1997.
[34] B.N. Datta, S. Elhay, and Y.M. Ram. An algorithm for the partial multiinput pole assignment problem of a secondorder control system. In Proceedings of the 35th IEEE Conference on Decision and Control, volume 2, pages 2025–2029, 1996. ISBN: 0780335910 0780335902 0780335929 0780335937.
[35] Y.M. Ram and S. Elhay. Construction of a quadratic pencil from eigenvalues. Zeitschrift fur Angewandte Mathematik und Mechanik, 76:13–16, 1996.
[36] Y.M. Ram and S. Elhay. An inverse eigenvalue problem for the symmetric tridiagonal quadratic pencil with application to damped oscillatory systems. SIAM J. Appl. Math., 56(1):232–244, 1996.
[37] Y.M. Ram and S. Elhay. The theory of a multi degree of freedom dynamic absorber. Journal of Sound and Vibration, 195(4):607–615, 1996.
[38] A. Torokhti, D. Gray, S. Elhay, P. Howlett, and W. Moran. A new technique for multidimensional signal compression. Proc. of the Fourth International Symposium on Signal Processing and Its Applications, 1:162–165, 1996.
[39] A. Torokhti, D. Gray, P. Howlett, S. Elhay, and W. Moran. Discrete rational tree transforms. Proc. of the Fourth International Symposium on Signal Processing and Its Applications, 1:425–426, 1996.
[40] A. Torokhti, D. Gray, P. Howlett, S. Elhay, and W. Moran. Hierarchical methods in matrix approximation. In Conference Digest (Part 1) of the IMA Conf. on Maths. in Signal Processing. University of Warwick, 1996.
[41] Y.M. Ram and S. Elhay. The construction of band symmetric models for vibratory systems from modal data. Journal of Sound and Vibration, 181(4):583–591, 1995.
[42] Y.M. Ram and S. Elhay. Dualities in vibrating rods and beams: continuous and discrete models. Journal of Sound and Vibration, 184:759–766, 1995.
[43] S. Elhay and J. Kautsky. Jacobi matrices for measures modified by a rational factor. Numerical Algorithms, 6:205–227, 1994.
[44] S. Elhay and J. Kautsky. Modified moments for classical weight functions modified by a rational factor. In H. Gardiner D. Stewart and D Singleton, editors, Computational Techniques and Applications: CTAC93, pages 221–229. World Scientific Publishing, 1994.
[45] S. Elhay. A direct method for the Jacobi matrix for exp(t) on a finite interval. In L. Colgan B.J. Noye, B. Benjamin, editor, Computational Techniques and Applications: CTAC91. Computational Mechanics Publications, Southampton, 1992.
[46] S. Elhay, G.H. Golub, and J. Kautsky. Jacobi matrices for sums of weight functions. BIT, 32:143–166, 1992.
[47] S. Elhay and J. Kautsky. Generalized Kronrod Patterson type imbedded quadratures. Aplikace Matematiky, 37(2):81–103, 1992.
[48] D. Boley, S. Elhay, G.H. Golub, and M. Gutknecht. Nonsymmetric Lanczos and finding orthogonal polynomials associated with indefinite weights. Numerical Algorithms, 1(1):21–43, 1991.
[49] S. Elhay, G.H. Golub, and J. Kautsky. Updating and downdating of orthogonal polynomials with data fitting applications. SIAM J. Matrix Anal. Appl., 12(2):327–353, 1991.
[50] S. Elhay, G.H. Golub, and J. Kautsky. Updating and downdating of orthogonal polynomials with data fitting applications. In G. Golub and P. Van Dooren, editors, NATO ASI Series F, pages 149–172. SpringerVerlag, 1990.
[51] P. Rabinowitz, S. Elhay, and J. Kautsky. Empirical mathematics: the first Patterson extension of GaussKronrod rules. Int. J. Computer Math., 36:119–129, 1990.
[52] S. Elhay and J. Kautsky. IQPACK: Fortran subroutines for the weights of interpolatory quadratures. ACM Trans. Math. Software, 4:399–415, 1987.
[53] P. Rabinowitz, J. Kautsky, S. Elhay, and J. Butcher. On sequences of imbedded integration rules. In P. Keast and G. Fairweather, editors, NATO advanced research workshop on numerical integration: Recent developments, software, and applications, pages 113–139. D Reidel Publ. Co, 1986.
[54] S. Elhay and J. Kautsky. A method for computing quadratures of the KronrodPatterson type. Australian Computer Science Communications, 6(1):15.1–15.8, 1984.
[55] J. Kautsky and S. Elhay. Gauss quadratures and Jacobi matrices for weight functions not of one sign. Math. Comp., 43(168):543–550, 1984.
[56] J. Kautsky and S. Elhay. Calculation of the weights of interpolatory quadratures. Numer. Math., 40:407–422, 1982.
[57] P.R. Baverstock and S. Elhay. Water balance of small lactating rodents  III. estimates of milk production and water recycling in lactating Mus Musculus under various water regimes. J. Math. Biology, 13:1–22, 1981.
[58] P.R. Baverstock and S. Elhay. Water balance of small lactating rodents  IV. rates of milk production in Australian rodents and the Guinea pig. Comp. Biochem. Physiol., 63A:241–246, 1979.
[59] S. Elhay and J.R. CasleySmith. Mathematical model of the initial lymphatics. Microvasc. Res., 12:121–140, 1976.
[60] S. Elhay. Optimal quadrature. Bull. Aust. Math. Soc., 1(1):81–108, 1969.
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Entry last updated: Saturday, 17 Nov 2018
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