• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1149-1158
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• 2000

A radioisotope tracer experiment was carried out in the submerged fixed bioreactor of a dye wastewater treatment facility to evaluate the flow behaviors in the 6 compartments of the reactor and to find any possible factors which may affect to the efficiency of the process. Approximately 20mCi of $^{131}I$ was injected into the system as a tracer and 8 radiation detectors were placed in the 6 compartments and at the inlet and the outlet of the system to measure the change of the tracer concentration with time. Using the Perfect Mixers in Series Model the measured data were analyzed to calculate the mean residence time and the characteristic parameters of the flow in the system. The mean residence time of the system was calculated as 17 hours which is 76% of the designed MRT(22.3hr). Among the 6 compartments, the first compartment doesn't show the characteristic of perfect mixer, whereas, the other 5 compartments are working as perfect mixers. The output response of the first compartment is fit well with the simulated output of a model which consists of a perfect mixer with an exchange volume. It indicates that a quarter of the tank volume is working as a dead volume or an exchange volume. From the measured residence time distributions in each compartment, the appropriate sampling times after the change of operational condition of the electron beam accelerator were evaluated.

• Journal of the Daesoon Academy of Sciences
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• v.25_2
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• pp.103-136
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• 2015

The theory of post-heaven provided Korea's many emerging national religions with spiritual ground. The I Ching originated in China emphasizes the principles of change or static aspects of world, while Right I Ching, which Il-Bu Kim suggested, underlines dynamic aspects of world. Il-Bu Kim is perceived to open a new stage in the history of philosophy of I Ching in this regard. His most remarkable contribution is the view of Great Opening Era of Post-Heaven, according to which the clock of cosmos shows the era of great change from Pre-Heaven to Post-Heaven and in the world of Post-Heaven everything will take its proper place. As to human society, Il-Bu Kim foresaw the change from disharmony to harmony, imbalance to balance and era of xiaoren to that of junzi. The advent of such a new world, however, asks human's moral revolution as a prerequisite. In the tradition of East Asian thought, human is the center of the Samjae, Heaven-Earth-Human and the only being which could participate in the growth of Heaven and Earth. Without the change of human mind, however, human can neither participate in the growth of Heaven and Earth nor expect the right change of Heaven and Earth. Even though the world of nature changes according to the principle of cosmic harmony, as the Right I Ching predicts, the real change of Heaven and Earth can be achieved only with moral change of human. The human in the Right I Ching is a free man who sticks to nothing and communicates with cosmos with empty mind. This is the very image of perfect man(至人). The perfect man in the Right I Ching is the main agent of everything, that's to say, the main agent of the great opening to Post-Heaven Era. This is the reason why most leaders of Koran emerging religions concentrate on the change of human. In this regard, Jeung-San Kang encouraged people to become the perfect man through the purification of mind and body and the great opening of inner man, depending on the metaphysical principle of the Right I Ching. Cheok and Resolution of grievances for the mutual beneficence of all life are what he suggested as a method of the great opening of inner man. Such a view is based on the thought that the accumulated sinful behaviors are obstacles to cosmic change and the time of mutual beneficience opens with the removal of the obstacles. If such religious practices are so effective, as Jeung-San Kang says, that future world could consist of perfect men who have achived the great opening of inner man, moral change, and change of consciousness, we could expect that the activities of xiaoren will be shrinked and junzi will be welcomed, as the Right I Ching predicts.

• Journal of applied mathematics & informatics
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• v.25 no.1_2
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• pp.283-291
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• 2007

A simple graph G is said to be fractional n-factor-critical if after deleting any n vertices the remaining subgraph still has a fractional perfect matching. For fractional n-factor-criticality, in this paper, one necessary and sufficient condition, and three sufficient conditions related to maximum matching, complete closure are given.

• Honam Mathematical Journal
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• v.23 no.1
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• pp.145-158
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• 2001

In this paper we investigated a replacement model with two types of repairs. Repairs are classified into minimal and perfect repair. An operating unit is completely replaced whenever it reaches age ${\tau}({\tau}>0)$(planned replacement). If it fails at age $t<{\tau}$, it is either restored by a entire unit with probability p(t)(perfect repair), or it undergoes minimal repair with probability $\bar{p}(t)=1-p(t)$. After a planned replacement, the procedure is repeated.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1319-1322
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• 2003

We present a web document summarizer, simpler more condense than the existing ones, of a search engine. This summarizer generates summaries with a statistic-based summarization method using Clustering or MMR technique to reduce redundancy in the results, and that generates summaries using Perfect Link Graph. We compare the results with the summaries generated by human subjects. For the comparison, we use FScore. Our experimental results verify the accuracy of the summarization methods.

• International Journal of Contents
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• v.1 no.1
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• pp.40-44
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• 2005

This paper introduces region partitioning method of non-perfect nested loops with non-uniform dependences. This kind of loop normally can't be parallelized by existing parallelizing compilers and transformations. Even when parallelized in rare instances, the performance is very poor. Based on the Convex Hull theory which has adequate information to handle non-uniform dependences, this paper proposes an enhanced region partitioning method which divides the iteration space into minimum parallel regions where all the iterations inside each parallel region can be executed in parallel by using variable renaming after copying.

• Journal of Industrial Technology
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• v.3
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• pp.27-32
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• 1983

This paper develops and provides formulas for calculating the Average Outgoing Quality and the Average Total Inspection for nine different sample/rest-of-lot disposition policies in which rectifying multiple sampling inspection by attribute can be carried out. The formulas are considered for perfect inspection as well as error-prone inspection.

• Kyungpook Mathematical Journal
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• v.46 no.1
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• pp.57-64
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• 2006

It is proved that if G is a direct sum of countable abelian $p$-groups and R is a special selected commutative unitary highly-generated ring of prime characteristic $p$, which ring is more general than the weakly perfect one, then the group of all normed units V (RG) modulo G, that is V (RG)=G, is a direct sum of countable groups as well. This strengthens a result due to W. May, published in (Proc. Amer. Math. Soc., 1979), that treats the same question but over a perfect ring.

• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.243-246
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• 2003

기존에 만들어진 미로 생성 알고리즘은 ‘Perfect 미로’를 지향하는 알고리즘이다. Perfect 미로는 두 점사이의 path가 유일하며, 순환되지 않고, 막힌공간이나, 접근할 수 없는 공간이 없는 미로를 말한다. 이런 미로 알고리즘을 사용하여 만든 미로는, 정형적인 형태를 띄게 된다. 이 알고리즘들을 아무런 수정 얼이, RPG/액션/시뮬레이션/전략게임 둥에 사용하게 되면, 게임 캐릭터는, 유일하면서 막힘이 빈번한 path 안에서 부자연스런 움직임을 가지게 될 것이다. 그래서 보다 넓은 면적을 탐험할 수 있고, 전진성을 높여주기 위하여 여러개의 path와 순환을 허용하는 알고리즘을 제안하게 되었다.

• Communications of the Korean Mathematical Society
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• v.34 no.3
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• pp.911-920
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• 2019

In this paper we characterize semiconformally flat spacetimes and a spacetime with harmonic semiconformal curvature tensor. At first in a semiconformally flat perfect fluid spacetime we obtain a state equation and prove that in particular for dimension n = 4, the spacetime represents a model for incoherent radiation. Next we prove that perfect fluid spacetime with harmonic semiconformal curvature tensor is of Petrov type I, D or O and the spacetime is a GRW spacetime. As a consequence we obtain several corollaries.