• Kyungpook Mathematical Journal
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• v.56 no.3
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• pp.745-754
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• 2016

In a graph G = (V, E), a non-empty set $S{\subseteq}V$ is said to be an open packing set if no two vertices of S have a common neighbour in G. The maximum cardinality of an open packing set is called the open packing number and is denoted by ${\rho}^{\circ}$. In this paper, we examine the effect of ${\rho}^{\circ}$ when G is modified by deleting a vertex.

• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.2
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• pp.287-298
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• 1993

In this study, generation characteristics and distribution situation of the animal fat residue were investigated to identify it's management problems and to propose alternatives for the recycling and final disposal. Generation sources were the meat distribution net-work including about 170 slaughterhouses, 280 meat-packing plants, thousands of meat shops and restaurants etc. The daily total amount of the animal fat residue is about 700 ton/day. More than 60% of the generation sources were concentrated in Seoul metropolitan area. The residue was collected by about 300 men using old-fashioned devices like handcarts, bike and auto bike, transported to the recycling plants by about 60 collection agencies. The residue was processed to produce by-products such as grease, tallow, animal feed ingredient in the recycling plants. At present, however, a great number of unlicensed, and mostly small rendering processors without having pollution control facilities do the unlawful business. These small, old fashioned and unorganized businesses are creating environmental problems by disposing the waste in improper ways such as open burning and dump. Improvement of the distribution network, the large-scale plants, and the estabilishing proper infrastructures were suggested to overcome the problems for the sound fat residues reprocessing industry.