• 한국통신학회논문지
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• 제41권12호
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• pp.1671-1683
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• 2016

부분접속 복구 부호(Locally Repairable Code)는 분산 저장 시스템(Distributed Storage System)의 효율적인 노드 복구(repair)를 위한 부호로서, 부분접속수(locality), 즉 복구 과정에서 사용되는 노드의 개수를 작게 함으로써 복구의 효율성을 높이는 것을 목적으로 한다. 본 논문에서는 각 노드의 부분접속수가 서로 다른 값으로 규정되는 상황을 다룬다. 다중 부분접속수에 대한 기존의 연구 결과를 ($r,{\delta}$)-부분접속수의 경우로 확장하여, 서로 다른 두 부분접속수로 규정되는 부호의 최소 거리 상계 및 이를 달성하는 최적 부호의 설계를 제시한다. 제안되는 상계는 기존의 연구와 달리 다중 부분접속수의 개수가 두 개로 제한되지만, 부호의 부분접속수가 정확하게 주어지지 않고 상한으로만 주어지는 보다 일반적인 경우에 직접 적용 가능하다.

• 전자공학회논문지C
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• 제34C권5호
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• pp.19-32
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• 1997

So far, the multiple path MINs to provide redundant paths in the traditional UPP MINs have been realized by adding additional hardware such as extra stages, duplicated data links, or multiple copies of sthe MIN. And the traditional MINs do not exploit locality: communication with all processor-memory paris takes the same amount of time. Also so far there has been little progress for exploiting locality of reference in MINs. In this paper, we present a new topology MIN, hybrid MIN that is constructed with 2N-3 SEs which is far fewer SEs than that of traditional MINs. Although the hybrid MIN is constructed with 2N-3 SEs, the hybrid MIN satisfies full access capability (FAC) and has redundant paths(but providing single path for 2 memory modules of each processor). Moreover the has redundant paths (but providing single path for 2 memory modules of each processor). Moreover the Hybrid MIN provides shortcut path between pairs which have frequent dat acommunication (locality of reference). Its performance under varing degrees of localized communication is analyzed.

• Journal of Ubiquitous Convergence Technology
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• 제1권1호
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• pp.28-34
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• 2007

Tree-based reliable multicast protocols provide scalability by distributing error-recovery tasks among several repair nodes. These repair nodes perform local error recovery for their receiver nodes using the data stored in their buffers. We propose a packet loss patterns adaptive feedback scheduling scheme to manage these buffers in an efficient manner. Under our scheme, receiver nodes send NAKs to repair nodes to request packet retransmissions only when the packet losses are independent events from other nodes. At dynamic and infrequent intervals, they also send ACKs to indicate which packets can be safely discarded from the repair node's buffer. Our scheme reduces delay in error recovery because the requested packets are almost always available in the repair node's buffers. It also reduces the repair node's workload because (a) each receiver node sends infrequent ACKs with non-fixed intervals and (b) their sending times are fairly distributed among all the receiver nodes.

• 아동학회지
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• 제21권2호
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• pp.99-118
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• 2000

This study investigated the self-concepts of Korean students based on Marsh and Shavelson's(1985) multidimensional hierarchical model. Reduced forms of the Self-Description Questionnaire(SDQ)-I and -II were administered to 308 5th and 6th grade students and 718 7th to 9th grade students. Results of 2 factor analyses indicated that sub-scales 9 and 11 were well established for SDQ-I and -II, respectively, partly confirming the multidimensionality of self-concept. The factors involving distinctions between academic and non-academic higher-order factors and between the academic/math and the academic/verbal factors were not so differentiated nor hierarchically arranged as proposed by the model. These differences may be attributed to the heavy influence of the academic self-concept on the other sub-factors. A Locality ${\times}$ Sex ${\times}$ Grade ANOVA showed main effects of locality favoring urban areas and of sex favoring boys.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2007년도 추계 종합학술대회 논문집
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• pp.135-139
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• 2007

최근 자연 환경 조사, 군사 응용 시스템, 환경 변화 감시 등의 여러 응용 분야에서 무선 센서 네트워크 자체를 데이터 저장 장치로 활용하는 데이터 중심 저장기법(DCS)에 대한 연구들이 진행되고 있다. 기존에 제안된 데이터 중심 저장기법들은 데이터들의 지역성이 고려되지 않아 범위질의 처리에 비효율적인 문제점(Q-NiGHT)과 센서 배포밀도가 불균일한 경우 각 센서의 데이터에 대한 저장 부하가 불균등해지는 문제점(KDDCS)을 갖는다. 본 논문에서는 이러한 기존의 문제점을 해결하고자, 데이터 저장 위치의 지역성(Locality)를 만족시키며 센서 배포 밀도를 고려한 새로운 데이터 중심 저장 기법을 제안한다. 제안하는 기법은 전체 센서 영역을 그리드로 나누고, 각 셀의 센서 밀도정보를 비트로 표현하는 배포 밀도 비트맵을 만들어 배포한다. 센서들은 데이터를 저장 하거나 탐색할 때 배포 밀도 비트맵을 이용하여 데이터 저장위치를 계산함으로써 별도의 통신 없이 최적의 저장위치를 선정할 수 있다. 본 논문에서는 시뮬레이션을 통해 기존 연구와의 성능 평가 하여 센서들의 배포밀도가 균일한 환경뿐만 아니라 불균일한 환경에서도 각 센서들의 데이터 저장부하를 고르게 분산시키고, 범위질의 처리 또한 효율적으로 처리됨을 보였다.

• Computers and Concrete
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• 제1권4호
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• pp.433-455
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• 2004

The paper presents results of FE-calculations on shear localizations in quasi-brittle materials during both an uniaxial plane strain compression and uniaxial plane strain extension. An elasto-plastic model with a linear Drucker-Prager type criterion using isotropic hardening and softening and non-associated flow rule was used. A non-local extension was applied in a softening regime to capture realistically shear localization and to obtain a well-posed boundary value problem. A characteristic length was incorporated via a weighting function. Attention was focused on the effect of mesh size, mesh alignment, non-local parameter and imperfections on the thickness and inclination of shear localization. Different methods to calculate plastic strain rates were carefully discussed.

• Steel and Composite Structures
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• 제35권1호
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• pp.147-157
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• 2020

In the present research, thermo-elastic buckling of small scale functionally graded material (FGM) nano-size plates with clamped edge conditions rested on an elastic substrate exposed to uniformly, linearly and non-linearly temperature distributions has been investigated employing a secant function based refined theory. Material properties of the FGM nano-size plate have exponential gradation across the plate thickness. Using Hamilton's rule and non-local elasticity of Eringen, the non-local governing equations have been stablished in the context of refined four-unknown plate theory and then solved via an analytical method which captures clamped boundary conditions. Buckling results are provided to show the effects of different thermal loadings, non-locality, gradient index, shear deformation, aspect and length-to-thickness ratios on critical buckling temperature of clamped exponential graded nano-size plates.

• 농촌계획
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• 제22권3호
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• pp.131-142
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• 2016

Urban agriculture, which can be defined as agriculture performed in a city, is suggested as an alternative solution to restore deserted community and expand green land in city area through cultivation activities. In Korea, 'Urban Agriculture Promotion and Support Act' was enforced from May 2012. In addition, in the same year, Seoul Metropolitan Government declared 'the beginning of urban agriculture era,' established municipal ordinance, and increased budget to actively support urban agriculture. As a result, urban agriculture practices have been increasing every year. Yet, the way of developing urban agriculture in a uniform way of expanding green land has led to difficulties of securing proper spaces. Accordingly, 'roof top' spaces have gained attention. This study analyzes rooftop garden, one of the spaces of carrying out urban agriculture, from the publicness perspective. The study selected a case study of a public rooftop garden in Mullae-dong, Yeongdeungpo-gu, investigated present conditions and usage features of the garden, and explored the conditions to be a 'public' roof top garden. Through theoretical analysis, both physical and non-physical indicators were derived for analysis framework; physical aspects- accessibility, locality, openness, comfortness, and non-physical aspects- subjectivity, cooperativeness, and a sense of community. The results of this study are as follows. First, openness and locality scores were the highest, and comfortness scored the lowest, in ensuring the publicness of Mullae roof top garden. Second, non-physical indicators had stronger effect than physical indicators on rooftop garden users' awareness on publicness and building a garden community. In conclusion, in order to vitalize roof top garden, users should be engaged from the very first planning stage of building a garden, opening hours should not be limited, and more importance should be put on users to subjectively manage the operation of rooftop garden than merely creating a physical environment.

• ETRI Journal
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• 제15권2호
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• pp.35-51
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• 1993

This paper presents function approximation based on nonparametric estimation. As an estimation model of function approximation, a three layered network composed of input, hidden and output layers is considered. The input and output layers have linear activation units while the hidden layer has nonlinear activation units or kernel functions which have the characteristics of bounds and locality. Using this type of network, a many-to-one function is synthesized over the domain of the input space by a number of kernel functions. In this network, we have to estimate the necessary number of kernel functions as well as the parameters associated with kernel functions. For this purpose, a new method of parameter estimation in which linear learning rule is applied between hidden and output layers while nonlinear (piecewise-linear) learning rule is applied between input and hidden layers, is considered. The linear learning rule updates the output weights between hidden and output layers based on the Linear Minimization of Mean Square Error (LMMSE) sense in the space of kernel functions while the nonlinear learning rule updates the parameters of kernel functions based on the gradient of the actual output of network with respect to the parameters (especially, the shape) of kernel functions. This approach of parameter adaptation provides near optimal values of the parameters associated with kernel functions in the sense of minimizing mean square error. As a result, the suggested nonparametric estimation provides an efficient way of function approximation from the view point of the number of kernel functions as well as learning speed.

• 전자공학회논문지B
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• 제33B권6호
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• pp.23-33
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• 1996

NUMA(Non-Uniform Memory Access)구조의 공유 메모리 다중처리기 시스템에서 참조 국지성의 활용은 병렬 처리의 성능에 큰 영항을 미친다. 본 논문에서는 운영체제가 참조 국지성을 관리하는데 도움을 주기위한 개선된 하드웨어 메모리 참조 카운터를 제시한다. 제신된 참조 카운터 방식에서는 기존의 참조 카운터들과는 달리 운영체제의 페이지 복사 정책을 다양한 메모리 참조 패턴에 적응시키기 위해 카운터의 값이 동적으로 그리고 주기적으로 조정된다. 우리는 실제 병렬 응용 프로그램들을 사용한 실행 구동형 시뮬레이션을 통해 제시된 "조정가능한 지연 카운터"가 이들의 성능에 미치는 영향을 평가하였다. 이 성능평가를 통해 '조정가능한 자연 카운터"를 이용한 메모리 복사 정책이 기존의 카운터를 이용한 정책보다 나은 성능을 보인다는 것과 시뮬레이션에 사용된 대부분의 병렬 응용 프로그램에 대해 고른 성능을 나타낸다는 것을 확인하였다.