• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.24-26
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• 2012

데이터 저장장치로 널리 사용되고 있는 플래시 메모리의 블록들은 소거 횟수가 제한되어 있어서 특정 블록에 소거 동작이 집중되지 않도록 마모 균등화 기능을 제공해야 한다. 저장 장치의 데이터들은 주기적으로 갱신이 자주 되는 hot데이터와 갱신이 거의 일어나지 않는 cold 데이터로 구성된다. 이런 두 가지 타입의 데이터로 인해 발생하는 소거 횟수에 대한 편차를 줄이기 위하여 정적 마모 균등화 기법을 사용하는데 데이터 이동에 따른 추가적인 소거 동작이 발생하게 된다. 본 논문에서는 데이터 이동 결정을 위한 임계값을 제어하여 플래시 메모리 내의 전체 블록들의 평균 소거 횟수가 크지 않을 때는 마모 균등화 작업을 자주 발생하지 않게 하고, 평균 소거 횟수가 소거 허용 한계치에 점차 근접하면 설정된 임계값으로 동작하도록 하여 정적 마모 평준화에 의해 추가되는 소거 횟수를 효율적으로 감소시키는 방법을 제안한다.

• The KIPS Transactions:PartD
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• v.13D no.3 s.106
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• pp.377-382
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• 2006

Advantageous features of flash memory are stimulating its exploitation in mobile and ubiquitous related devices. The hardware characteristics of flash memory however place restrictions upon this current trend. In this paper, a cleaning policy for flash memory is proposed in order to decrease the necessary penally for recycling of memory minimizing the degradation of performance at the same time. The proposed cleaning algorithm is based on partitioning of candidate memory regions, to be reclaimed as free, into a number of groups. In addition, in order to improve the balanced utilization of the entire flash memory space in terms of 'wearing-out', a free segment selection algorithm is discussed. The impact of the proposed algorithms is evaluated through a number of experiments. Moreover, the composition of the optimal configuration featuring the proposed methods is tested through experiments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.57-62
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• 2014

The benefits of infrastructure support are shown by analyzing a throughput scaling law of an erasure network in which multiple relay stations (RSs) are regularly placed. Based on suitably modeling erasure probabilities under the assumed network, we show our achievable network throughput in the hybrid erasure network. More specifically, we use two types of physical models, a exponential decay model and a polynomial decay model. Then, we analyze our achievable throughput using two existing schemes including multi-hop transmissions with and without help of RSs. Our result indicates that for both physical models, the derived throughput scaling law depends on the number of nodes and the number of RSs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.5
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• pp.389-394
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• 2004

In this paper, according to characteristics of flash memory, a memory recycling method is proposed in order to decrease the necessary cost preventing performance degradation at the same time, In order to optimize the demanding costs, the new approach partitions the search space of flash memory segments into K segment groups, A method for memory space allocation, in addition, is proposed in order to satisfy the goal of even wearing over the total memory space, The optimized configuration of the proposed method is achieved through experiments, The fact that the newly proposed methods outperform the existing approaches regarding cost and performance is evaluated by simulations, Furthermore the experimental results demonstrate that the memory allocation method affects even wearing in great deal.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.4
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• pp.39-54
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• 2017

Between 1998 and 2010, the computerization of underground facilities was completed in 84 cities. Since 2011, new pipelines have been laid or existing pipelines have been maintained, renovated, and renewed. To measure the exact location and depth of the exposure pipe, a map of underground facilities was created before filling the ground. This method is based on the time when the underground facilities of the National Geographic Information Institute Regulation No. 134 of the National Geographic Information Office revised in 2010 were drafted. The process of the drone taking the video is based on a theoretical basis of ground control points. The method works by removing all ground control points located outside of the error range and re-processing it for calculating the best result. Furthermore, using a drone-based spontaneous measuring method allows workers to obtain a high accuracy underground facilities map in error bound. The proposed method could be used as a new way to standardize the processing.