• ETRI Journal
• /
• v.34 no.2
• /
• pp.199-209
• /
• 2012

In transport networks, a multi-ring architecture is very useful to facilitate network planning and to design and provide more resilient services for customers. Unlike traditional synchronous optical network multi-rings, the service resiliency of Ethernet-based multi-rings is significantly impacted by the ring hierarchy because a link or node failure in a certain level ring triggers filtering database flush actions in all higher level rings as well as in the ring with the failure, and consequently a large amount of duplicated data frames may be flooded. In this paper, we investigate how the ring hierarchy impacts the service resiliency of multi-ring networks. Based on extensive experiments on various single- and multiple-link failures, we suggest two effective inter-ring connection rules to minimize the transient traffic and to ensure more resilient multi-ring networks. In addition, we consider a flush optimization technique called e-ADV, and show that the combination of e-ADV and multi-ring structures satisfying our inter-ring connection rules results in a more attractive survivability performance.

• Journal of the Korean Mathematical Society
• /
• v.50 no.5
• /
• pp.973-989
• /
• 2013

We observe from known results that the set of nilpotent elements in Armendariz rings has an important role. The upper nilradical coincides with the prime radical in Armendariz rings. So it can be shown that the factor ring of an Armendariz ring over its prime radical is also Armendariz, with the help of Antoine's results for nil-Armendariz rings. We study the structure of rings with such property in Armendariz rings and introduce APR as a generalization. It is shown that APR is placed between Armendariz and nil-Armendariz. It is shown that an APR ring which is not Armendariz, can always be constructed from any Armendariz ring. It is also proved that a ring R is APR if and only if so is R[$x$], and that N(R[$x$]) = N(R)[$x$] when R is APR, where R[$x$] is the polynomial ring with an indeterminate $x$ over R and N(-) denotes the set of all nilpotent elements. Several kinds of APR rings are found or constructed in the precess related to ordinary ring constructions.

• Journal of the Korean Mathematical Society
• /
• v.53 no.2
• /
• pp.381-401
• /
• 2016

According to Jacobson [31], a right ideal is bounded if it contains a non-zero ideal, and Faith [15] called a ring strongly right bounded if every non-zero right ideal is bounded. From [30], a ring is strongly right AB if every non-zero right annihilator is bounded. In this paper, we introduce and investigate a particular class of McCoy rings which satisfy Property (A) and the conditions asked by Nielsen [42]. It is shown that for a u.p.-monoid M and ${\sigma}:M{\rightarrow}End(R)$ a compatible monoid homomorphism, if R is reversible, then the skew monoid ring R * M is strongly right AB. If R is a strongly right AB ring, M is a u.p.-monoid and ${\sigma}:M{\rightarrow}End(R)$ is a weakly rigid monoid homomorphism, then the skew monoid ring R * M has right Property (A).

• Communications of the Korean Mathematical Society
• /
• v.25 no.3
• /
• pp.349-364
• /
• 2010

P. M. Cohn called a ring R reversible if whenever ab = 0, then ba = 0 for a, $b\;{\in}\;R$. Commutative rings and reduced rings are reversible. In this paper, we extend the reversible condition of a ring as follows: Let R be a ring and $\alpha$ an endomorphism of R, we say that R is right (resp., left) $\alpha$-shifting if whenever $a{\alpha}(b)\;=\;0$ (resp., $\alpha{a)b\;=\;0$) for a, $b\;{\in}\;R$, $b{\alpha}{a)\;=\;0$ (resp., $\alpha(b)a\;=\;0$); and the ring R is called $\alpha$-shifting if it is both left and right $\alpha$-shifting. We investigate characterizations of $\alpha$-shifting rings and their related properties, including the trivial extension, Jordan extension and Dorroh extension. In particular, it is shown that for an automorphism $\alpha$ of a ring R, R is right (resp., left) $\alpha$-shifting if and only if Q(R) is right (resp., left) $\bar{\alpha}$-shifting, whenever there exists the classical right quotient ring Q(R) of R.

• Bulletin of the Korean Mathematical Society
• /
• v.49 no.2
• /
• pp.381-394
• /
• 2012

We generalize the insertion-of-factors-property by setting nilpotent products of elements. In the process we introduce the concept of a nil-IFP ring that is also a generalization of an NI ring. It is shown that if K$\ddot{o}$the's conjecture holds, then every nil-IFP ring is NI. The class of minimal noncommutative nil-IFP rings is completely determined, up to isomorphism, where the minimal means having smallest cardinality.

• Journal of the Korea Furniture Society
• /
• v.23 no.1
• /
• pp.95-102
• /
• 2012

The objective of this study was to conduct the species identification and tree-ring dating of Lotus Pedestal of the Amitabha Statue at Ssangbong-Temple in Hwasun. The six wood blocks used for the Lotus Pedestal were hard pines (Pinus spp.; diploxilon) except one piece which was ginkgo (Ginkgo biloba L.). The lotus leaves surrounding the pedestal body were also made of ginkgo. Tree-ring patterns of 3 blocks were synchronized and a 133 years chronology was made. The chronology was crossdated well with the master chronology of Japanese red pine in South Korea. It dated back to A. D. 1551~1683, i.e. the last ring dated A. D. 1683. Through the estimation of the number of sapwood rings removed during carving, the felling year was calculated A. D. $1704{\pm}10$. The calligraphic writing on the Pedestal indicated that this statue was made in A. D. 1694. Therefore, the accuracy of the tree-ring dating has been proven.

• Bulletin of the Korean Mathematical Society
• /
• v.39 no.1
• /
• pp.1-8
• /
• 2002

We characterize the commutative Artinian rings R every proper quotient ring (respectively every proper ideal) in which is invariant with respect to all derivations.

• Journal of the Chungcheong Mathematical Society
• /
• v.15 no.2
• /
• pp.35-39
• /
• 2003

In this paper we study a ring over which every left module of finite length has an injective hull of finite length. We consider a ring that is a finite intermediate normalizing extension ring of such a ring. We also consider the subrings of such a ring.

• Journal of the Chungcheong Mathematical Society
• /
• v.14 no.2
• /
• pp.19-26
• /
• 2001

All rings are assumed to be associative but do not necessarily have an identity. In this paper, we carry out a study of ring theoretic properties of formal triangular matrix rings. Some results are obtained on these rings concerning properties such as being $I_0$-ring, I-ring, exchange ring.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.10
• /
• pp.1347-1356
• /
• 2013

Tricholoma matsutake, an ectomycorrhiza that has mutual relationships with the rootlet of Pinus denisflora, forms a fruiting body that serves as a valuable food in Asia. However, the artificial culture of this fungus has not been successful. Soil fungi, including T. matsutake, coexist with many other microorganisms and plants; therefore, complex microbial communities have an influence on the fruiting body formation of T. matsutake. Here, we report on the structures of fungal communities associated with the fairy ring of T. matsutake through the pyrosequencing method. Soil samples were collected inside the fairy ring zone, in the fairy ring zone, and outside the fairy ring zone. A total of 37,125 sequencing reads were obtained and 728 to 1,962 operational taxonomic units (OTUs) were observed in the sampling zones. The fairy ring zone had the lowest OTUs and the lowest fungal diversity of all sampling zones. The number of OTUs and fungal taxa inside and outside the fairy ring zone was, respectively, about 2 times and 1.5 times higher than the fairy ring. Taxonomic analysis showed that each sampling zone has different fungal communities. In particular, out of 209 genera total, 6 genera in the fairy ring zone, such as Hemimycena, were uniquely present and 31 genera, such as Mycena, Boletopsis, and Repetophragma, were specifically absent. The results of metagenomic analysis based on the pyrosequencing indicate a decrease of fungal communities in the fairy ring zone and changes of fungal communities depending on the fairy ring growth of T. matsutake.