This paper considers a route optimization problem in advanced electrical
PCB inspections. By considering the constraint that “camera-based alignment of
position” needs to be conducted before electrical tests, the PCB inspection route optimization
problem (PCBIRP) is modeled as a precedence-constrained traveling salesman
problem (PCTSP), especially, as a pickup and delivery traveling salesman problem
(PDTSP). Two of mixed 0-1 integer programming problem formulations are proposed.
The computational times for the proposed formulations are compared by solving benchmark
instances using some of well-known mathematical programming solvers.
The aim of the present paper is devoted to discuss some more properties
of γ-irresolute mappings and contra-γ-irresolute mappings. Also, we introduce and
study two new weak homeomorphisms such as contra-γr-homeomorphisms and contra-
γ-homeomorphisms. Further, we investigate some groups related to the mappings above
and some examples of them on digital lines.
We consider a one dimensional isentropic periodic flow of a compressible
viscous fluid driven by a self-gravitation of the fluid. We show the existence of an
unbounded solution of a system describing the flow. A sufficient condition for the
unboundedness is given in terms of the initial values of an energy form.
We prove that an ordered hypersemigroup H is left (resp. right) regular
if and only if every left (resp. right) ideal of H is semiprime and it is
intra-regular if and only if every ideal of H is semiprime. Then we prove
that an ordered hypersemigroup H is left (resp. right) regular if and only
if every fuzzy left (resp. right) ideal of H is fuzzy semiprime and it is
intra-regular if and only if every fuzzy ideal of H is fuzzy semiprime.
This paper serves as an example to show the way we pass from ordered
groupoids (ordered semigroups) to ordered hypergroupoids (ordered hypersemigroups),
from groupoids (semigroups) to hypergroupoids (hypersemigroups).
The results on semigroups (or on ordered semigroups) can
be transferred to hypersemigroups (or to ordered hypersemigroups) in the
way indicated in the present paper.