Spaces Places Species Arvind Elango Soma Vemulapalli Bill Baykan Terry Harrison Introduction ● ● ● Digital Libraries Want data survivability in a networked environment (redundancy, distribution) How to load the system with documents? Model ● Species - asexual single-cell organism (record) ● Places or Islands (servers) ● Spaces (amount of room for organisms) Goal ● To find a method of evaluating the carrying capacity of various configured systems to provide maximum survivability Parameters ● Local comfort ● Global comfort ● Number of “Spaces” - islands ● Number of “Places” - room on each island ● Number of unique “Species” Population Rules (for each island) ● ● ● ● Each species introduced will seek to achieve the predetermined local and exceed the global comfort level (ie 2 per island/ 50% of islands) A new species may replicate itself on the island if empty places are available (ie 11x | 11x| 11x ---> 222 | 112 | 112) A new species may replace a duplicate of another species on an island (ie 112 ---> 312) there is still one 1 present A new species may replace a member of another species if the other species is above its global comfort level ( ie 222 | 112 | 112 ---> 333 312 112) Population Example ___ ___ ___ 1 1 0 2 2 2 3 3 3 ___ ___ ___ 1 1 0 1 1 2 3 1 2 Local comfort =2 Global comfort = 50% Number of species = 3 Number of space = 3 Number of islands = 3 ___ ___ ___ 1 1 0 1 1 2 3 1 2 Modeling -Disturbance Phase ● System disruptions shall be simulated by the random deletion of islands followed by the creation of a new island ● Balancing follows ● 100 iterations per test load ● Passes if no extinctions Test 1 ● Number of places fixed at 5 ● Local comfort = 2 ● Global comfort = 30% ● Determine how carrying capacity changes as number of islands is increased Test 2 ● Number of places fixed at 10 ● Local Comfort = 2 ● Global Comfort set to 30% ● Determine how carrying capacity changes as number of islands is increased Test 3 (Varying global comfort) ● Number of places = 5 ● Local comfort = 2 ● ● Global comfort = 10%,30%,50% (paranoia knob) Determine how carrying capacity changes as number of islands is increased Results The stability of the system is reasonably high when the number of species, spaces and places are equal. Spaces vs Species 25 22.5 No. of Species 20 17.5 15 5 Islands 10 Islands 12.5 10 7.5 5 2.5 0 1 2 3 4 5 6 7 No. of Spaces 8 9 10 20 No. of Species Species vs Island 14 13 12 11 10 9 8 7 6 5 5 spaces 10 spaces 4 3 2 1 0 1 2 3 4 5 6 7 8 9 No. of Islands 10 20 30 40 Conclusions With a constant number of islands, the number of species which can be maintained increases linearly with the number of spaces. ● With a fixed number of spaces, the carrying capacity increases up to a certain number of islands (depending upon the algorithm and the global comfort level) and then saturates. This observation needs to be analyzed further. ● Future Possibilities ● ● Tuning “Paranoia knob” of individual species Self adjusting “knob” in response to network threat (on both system/species level)