• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.5
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• pp.370-376
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• 2020

In this study, we consider a group-based random access method for group connection and delivery by grouping devices when H2H devices and large-scale M2M devices coexist in a cell in NB-IoT environment. H2H devices perform individual random access, but M2M devices are grouped according to a NPRACH transmission period, and a leader of each group performs random access. The preamble is allocated using the variable preamble allocation algorithm of the Disjoint Allocation(DA) method. The proposed preamble allocation algorithm is an algorithm that preferentially allocates preambles that maximizes throughput of H2H to H2H devices and allocates the rest to M2M devices. The access distribution of H2H and M2M devices was set as Poisson distribution and Beta distribution, respectively, and throughput, collision probability and resource utilization were analyzed. As the random access transmission slot is repeated, the proposed preamble allocation algorithm decreases the collision probability from 0.93 to 0.83 and 0.79 when the number M2M device groups are 150. In addition, it was found that the amount of increase decreased to 33.7[%], 44.9[%], and 48.6[%] of resource used.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.357-358
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• 2007

• Journal of Korea Water Resources Association
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• v.32 no.4
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• pp.489-499
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• 1999

This research investigated the applicapability of an improved algorithm to calculate the topographic index, ln($\alpha$/tan B), for the topography of Korea employing channel initiation threshold area(CIT) and an exponent for the gradient(H). hanjaechun subwatershed in Cheongdochun and Dongok subwatershed in Wichun test watershed were selected as study areas. The digital elevation models(DEM) of study areas have been made with the resolution from 10m to 100m. Application of CIT to the traditional algorithm provide reasonable computation method in considering channel pixel impact. Introduction of the gradient exponent(H) made it possible to obtain better flow convergence effect in concave topography comparing with the traditional multiple flow direction algorithm. The improved algorithm shows the capability to relax the overestimation problem of rising limb of hydrograph through reducing overestimated high value of topographic index.

• Journal of applied mathematics & informatics
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• v.31 no.3_4
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• pp.565-575
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• 2013

Let H be a real Hilbert space and let T : H ${\rightarrow}$ H be a Lipschitz pseudocontractive mapping. We introduce a modified Ishikawa iterative algorithm and prove that if $F(T)=\{x{\in}H:Tx=x\}{\neq}{\emptyset}$, then our proposed iterative algorithm converges strongly to a fixed point of T. No compactness assumption is imposed on T and no further requirement is imposed on F(T).

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.1-5
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• 2008

Although we can make a sparse matrices for LDPC codes, the encoding complexity per a block increases quadratically by $n^2$. We propose modified PEG algorithm using PEG algorithm having a large girth by establishing edges or connections between symbol and check nodes in an edge-by-edge manner. M-PEG construct parity check matrices. So we propose parity check matrices H form a dual-diagonal matrices that can construct a more efficient decoder using a M-PEG(modified Progressive Edge Growth).

• Journal of KIISE:Software and Applications
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• v.27 no.12
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• pp.1227-1237
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• 2000

Hindley/Milner let-다형성 타입체계(let-polymorphic type system)에는 두 가지 타입 유추(type-inference) 알고리즘이 있다. 하나는 표준으로 알려진 W 알고리즘으로 프로그램의 문맥에 상관없이 상향식으로 유추하는 알고리즘이고, 다른 하나는 프로그램의 문맥에 따라 하양식으로 유추하는 M 알고리즘이다. 본 연구에서는 함수 적용(application)이 중첩되는 경우, M 알고리즘에 병목현상이 발생함을 보이고, 이러한 병목현상이 발생하지 않는 혼성 알고리즘 H를 제시한다. H 알고리즘은 M 알고리즘을 함수 적용 부분만 W 알고리즘으로 변형한 알고리즘으로, W보다 일찍 M보다는 늦게 오류를 감지함을 보인다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.631-632
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.65-66
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.499-500
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.121-122
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• 2009