Goal nodes

Search trees are widely used to represent the different states that a problem cem adopt, example is shown in Figure 9.4 from which it should be clear where the name deri especially if the page is turned upside down. A tree contains nodes that are connected edges. The presence of an edge indicates that the two nodes it connects ctre related in so way. Each node represents a state that the system may adopt. The root node represents initial state of the system. Terminal nodes have no child nodes. A goal node is a special k of terminal node that corresponds to Em acceptable solution to the problem. 

The rule set for the PSG model is very simple. Initially, the status of the PSGRAPH is examined to see if the process should terminate. The rules written here specify that if the status of the PSGRAPH is FAILED or SUCCEEDED then the graph is output and the process halts. Otherwise, If there is a node marked as a possible node to sprout, the goal node is picked first. On the other hand, the presence of a trynode which has no subgoals indicates that the completed and the action to take is to trynode and EVALUATE it. The... 

The main idea is first to semantically enrich the GSN nodes in the argument structure. Thus, in addition to the descriptive text, e.g., the actual claim for a goal node, we associate nodes with metadata, given as a set of attributes. 

While all tree search techniques involve the expansion of nodes, one can proceed in a number of different ways. Systematic exploration at each level, even with six conformational states, is possible only for molecules consisting of six or seven conformational units. Beyond this size it is necessary to rely on some form of heuristic search which provides the means of finding a path between the root node and a goal node without generating all conformations at the intermediate levels. 

The function e([< + l,n]) in equation (1) should never overestimate the actual cost of reaching the goal node from the node being evaluated, because this could imply eliminating the path leading to an optimal solution. On the other hand, the... 

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