LISA Version 2.00 (Final Draft)---June 1991

• A separate installation procedure is no longer required. LISA version 2.00 is distributed as a self-extracting PKZIP file. To install Version 2.00, navigate to the disk and subdirectory in which you want LISA, and run LISA200.EXE (see part 2, section 1.2 of the manual). Specifying the path to data files is now performed from within LISA (see part 2, section 3.4).
• Version 2.00 has an improved user interface, and includes two new data plotting options -- scatter plot and histogram -- to view the simulated (or calculated) values of the input variables and several calculated variables.
• Individual values of soil cohesion (Cs') and friction angle (ø') are now sampled, rather than values of soil shear strength as was done in Version 1.05. (Compare section 2.5.2 of the Peer Review Draft Documentation with section 4.2 of the version 2.0 manual.) This change was required to make LISA compatible with the Level II program, Stability Analysis for Road Access (SARA), which requires individual values for soil cohesion and friction angle in its computational algorithms The consequence of this change is that Version 2.00 can handle correlation between Cs' and ø' only by using the bivariate normal PDF. All univariate PDF's assume that the correlation coefficient, r, between Cs' and ø' is zero. In LISA version 1.05 an r between Cs' and ø' could be specified for any PDF type. When data files created using Version 1.05 are read into Version 2.00, the PDF types specified for Cs' and ø' remain unchanged, and the old r value will appear in a message in the upper left-hand corner of the screen to alert you that r was non-zero. You may use the old PDF's with an r of zero, or change to a bivariate normal PDF and use the old r. Either way, you will get a different answer than you got using Version 1.05 (see below). We recommend that you do both and compare the results.
• Because Version 2.00 differs in how it simulates soil shear strength values, it will give slightly different probability of failure (Pf) values than does Version 1.05 when the same random number seed is used, even when Cs' and ø' were not correlated in Version 1.05. Usually the difference is on the order of a few thousandths. When correlation was considered in Version 1.05, the difference in Pf values between the two versions can be a few hundredths, depending on the input PDF's used. However, in general, the difference should not be greater than the difference in Pf values obtained by using different random number seeds with one version.
• Version 2.00 will read input data files created with Version 1.05. However, you do need to be aware of how a correlation between Cs' and ø' is handled differently in Version 2.00, as discussed below. Data files can be left in the map unit subdirectories created by Version 1.05 and accessed using Version 2.00 by specifying the correct path (see part 2, section 3.4 of the Version 2.0 documentation).

LISA Version 1.05 (Peer Review Draft)---June 1989

DLISA Version 1.05---7/91