Abstract The unit process life cycle inventory is a modeling approach to estimate the energy demand and resource requirements of process. Thus, model for specific manufacturing can be used quantifying environmental impacts products manufactured by that Within approach, reusable models are developed processes. In this paper, development validation high-speed laser directed deposition presented. ...

Let D be a digraph, V (D) and A(D) will denote the sets of vertices and arcs of D, respectively. A (k, l)-kernel N of D is a k-independent set of vertices (if u, v ∈ N then d(u, v), d(v, u) ≥ k) and l-absorbent (if u ∈ V (D) − N then there exists v ∈ N such that d(u, v) ≤ l). A k-kernel is a (k, k − 1)-kernel. A digraph D is cyclically k-partite if there exists a partition {Vi} i=0 of V (D) suc...

A digraph is called k-cyclic if it cannot be made acyclic by removing less than k arcs. It is proved that for every > 0 there are constants K and δ so that for every d ∈ (0, δn), every n2-cyclic digraph with n vertices contains a directed cycle whose length is between d and d+K. A more general result of the same form is obtained for blow-ups of directed cycles.

In the incremental cycle detection problem arcs are added to a directed acyclic graph and the algorithm has to report if the new arc closes a cycle. One seeks to minimize the total time to process the entire sequence of arc insertions, or until a cycle appears. In a recent breakthrough, Bender, Fineman, Gilbert and Tarjan [6] presented two different algorithms, with time complexity O(n log n) a...

A cycle basis of a graph is a family of cycles which spans all cycles of the graph. In an undirected graph, a cycle is simply a set of edges with respect to which every vertex has even degree. We view cycles as vectors indexed by edges. The entry for an edge is one if the edge belongs to the cycle and is zero otherwise. Addition of cycles corresponds to vector addition modulo 2 (symmetric diffe...

We survey results concerning various generalizations of tournaments. The reader will see that tournaments are by no means the only class of directed graphs with a very rich structure. We describe, among numerous other topics mostly related to paths and cycles, results on hamiltonian paths and cycles. The reader will see that although these problems are polynomially solvable for all of the class...

We consider the priority-based allocation problem: there is a set of indivisible objects with multiple supplies (e.g., schools with seats) and a set of agents (e.g., students) with priorities over objects (e.g., proximity of residence area). We study two well-known and competing mechanisms. The agentoptimal stable mechanism (AOSM) allots objects via the deferred acceptance algorithm. The top tr...