Efficient code constructions for certain two-dimensional constraints

Efficient encoding algorithms are presented for two types of constraints on two-dimensional binary arrays. The first constraint considered is that of t-conservative arrays, where each row and each column has at least t transitions of the form `0´→`1´ or `1´→`0.´ The second constraint is that of two-dimensional DC-free arrays, where in each row and each column the number of `0´s equals the number of `1´s