A simple design method using dynamic programming is proposed for good LDPC codes with relatively low code-rate. By applying a dynamic programming optimization to the construction of the portion fixed for easy encoding in the parity-check matrix, we can maximize the girth associated with columns contained in that portion of the matrix. Simulation results show performance improvement over the con...

In this paper we propose a new class of irregular low-density parity check (LDPC) codes with linear encoding complexity. We show that these codes offer performances compatible with irregular LDPC codes with randomly generated parity-check matrices. The non-systematic part of the paritycheck matrix has a simple triangular structure, which enables linear encoding, while the systematic part of the...

Eroded sediments from catchment areas transport by streams and deposit in downstream less steep areas. Despite reducing the useful life of various hydraulic structures including reservoir dams, flood walls, and bridges, this phenomenon changes the main river hydraulic conditions and increases the flood prone farms in the riverbank area. Check dams are among the structures that can prevent form ...

Check dams are one of the structures used to control debris flows. In this study, in order to evaluate the effect of hydraulic parameters on debris sediment trapping rate by the slit trapezoidal check dams with different angles, and to develop an empirical relation for determination of trapping coefficient of the dam reservoirs, three physical models of the check dams were used. The tests were ...

Studies in fission and budding yeast have continuously led the way for analyzing pathways of cell division. Two elegant studies, one from each yeast species, are opening the gates to study one of the final steps of mitosis--silencing the spindle checkpoint.

teacher questions are claimed to be constitutive of classroom interaction because of their crucial role both in the construction of knowledge and the organization of classroom proceedings (dalton puffer, 2007). most of previous research on teachers’ questions mainly focused on identifying and discovering different question types believed to be helpful in creating the opportunities for learners’...

Stefan Schulz and Marthinus Hamutenya* Polytechnic of Namibia 2003 Abstract: Namibia is a newly independent nation, which in the wake of colonial oppression and foreign rule has yet to develop a comprehensive juvenile justice system. The current criminal justice system is informed by stereotyped common sense concepts of ‘criminality’ and ‘the criminal’. Simplistic views undergirded by utilitari...