Hypergraphic matroids were de ned by Lorea as generalizations of graphic matroids. We show that the minimum cut (co-girth) of a multiple of a hypergraphic matroid can be computed in polynomial time. It is well-known that the size of the minimum cut (co-girth) of a graph can be computed in polynomial time. For connected graphs, this is equivalent to computing the co-girth of the circuit matroid....

Girth pairs were introduced by Harary and Kovács [Regular graphs with given girth pair, J. Graph Theory 7 (1983) 209–218]. The odd girth (even girth) of a graph is the length of a shortest odd (even) cycle. Let g denote the smaller of the odd and even girths, and let h denote the larger. Then (g, h) is called the girth pair of the graph. In this paper we prove that a graph with girth pair (g, h...

A method to construct girth-12 (3,L) quasi-cyclic lowdensity parity-check (QC-LDPC) codes with all lengths larger than a certain given number is proposed, via a given girth-12 code subjected to some constraints. The lengths of these codes can be arbitrary integers of the form LP, provided that P is larger than a tight lower bound determined by the maximal element within the exponent matrix of t...

It is well known that 3–regular graphs with arbitrarily large girth exist. Three constructions are given that use the former to produce non-Hamiltonian 3–regular graphs without reducing the girth, thereby proving that such graphs with arbitrarily large girth also exist. The resulting graphs can be 1–, 2– or 3–edge-connected depending on the construction chosen. From the constructions arise (nai...

ABSTRACT The application of on-line monitoring system for recording main welding parameters during electric arc stud welding process at different electric arc stability changes is described in this paper. In the first part of the paper, the basics of electric arc stud welding process, and equipment for stud welding and process monitoring used in experimental part is described. In the second par...

Friction stir welding and tungsten inert gas welding techniques were employed to weld armor grade aluminum alloy to investigate the effect of welding processes on tensile behavior of weld joints. Tensile tests, Vicker microhardness tests and optical microscopy were performed on developed weld joints and base metal. Welding process influenced tensile behavior and microstructure of weld joints. F...

In an effort to increase a productivity of welding process and to reduce the impact to workers from industrial disaster, the research in the field of welding automation is sharply increasing in shipbuilding industry. DSME had developed and successfully applied a welding robot system for grand assembly line in OKPO shipyard in 1997 and has recently developed multi welding robot system for the su...

Welding is a process during which fumes, gases, electromagnetic radiation and noise are emitted as by-products. Metal oxide particles are particularly hazardous components of welding fumes. Welding has been found to be associated with respiratory symptoms and our objective in the present study was to study the effects of welding on pulmonary function and serum oxidant-antioxidant status. Fifty-...

Today, welding tasks can be accomplished in two ways: 1) Manual or conventional, which is made by humans with a welding gun; and 2) Automated welding that is carried out by robots, this robots are called “Welding Robots”. Current welding robots are able to perform welding tasks continuously under different working conditions in low-scale production such as shipbuilding or in high-scale producti...

An evaluation of reproductive performance, behavior, immunity and ergonomics was conducted for two common sow housing systems: the girth tether and crate. Littermate Yorkshire × Landrace gilts were randomly assigned to either the crate or girth tether system and they remained in that treatment for two consecutive pregnancies and lactations. A total of 171 matings resulted in 141 litters (82.4% ...