@TechReport{	  it:2008-019,
  author	= {Ken Mattsson and Frank Ham and Gianluca Iaccarino},
  title		= {Stable Boundary Treatment for the Wave Equation on
		  Second-Order Form},
  institution	= {Department of Information Technology, Uppsala University},
  department	= {Division of Scientific Computing},
  year		= {2008},
  number	= {2008-019},
  month		= jun,
  abstract	= {A stable and accurate boundary treatment is derived for
		  the second-order wave equation. The domain is discretized
		  using narrow-diagonal summation by parts operators and the
		  boundary conditions are imposed using a penalty method,
		  leading to fully explicit time integration. This
		  discretization yields a stable and efficient scheme. The
		  analysis is verified by numerical simulations in
		  one-dimension using high-order finite difference
		  discretizations, and in three-dimensions using an
		  unstructured finite volume discretization.}
}