• Title/Summary/Keyword: Memory research

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Design of an Automated Testing Tool to Detect Dynamic Memory Access Errors in C Programs (C언어 기반 프로그램의 동적 메모리 접근 오류 테스트 자동화 도구 설계)

  • Cho, Dae-Wan;Oh, Seung-Uk;Kim, Hyeon-Soo
    • Journal of KIISE:Software and Applications
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    • v.34 no.8
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    • pp.708-720
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    • 2007
  • Memory access errors are frequently occurred in computer programs written in C programming language [1,2]. Accordingly, a number of research works have suggested a wide variety of methods to detect such errors automatically. However, they have one or more of the following problems: inability to detect all memory errors, changing the memory allocation mechanism, and excessive performance overhead. To cope with these problems, in this paper we suggest a new and automated tool to detect dynamic memory access errors in C programs.

An Empirical Evaluation Analysis of the Performance of In-memory Bigdata Processing Platform (메모리 기반 빅데이터 처리 프레임워크의 성능개선 연구)

  • Lee, Jae hwan;Choi, Jun;Koo, Dong hun
    • Journal of Korea Society of Industrial Information Systems
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    • v.21 no.3
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    • pp.13-19
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    • 2016
  • Spark, an in-memory big-data processing framework is popular to use for real-time processing workload. Spark can store all intermediate data in the cluster memory so that Spark can minimize I/O access. However, when the resident memory of workload is larger that the physical memory amount of the cluster, the total performance can drop dramatically. In this paper, we analyse the factors of bottleneck on PageRank Application that needs many memory through experiment, and cluster the Spark with Tachyon File System for using memory to solve the factor of bottleneck and then we improve the performance about 18%.

Effects of Financial Crises on the Long Memory Volatility Dependency of Foreign Exchange Rates: the Asian Crisis vs. the Global Crisis

  • Han, Young Wook
    • East Asian Economic Review
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    • v.18 no.1
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    • pp.3-27
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    • 2014
  • This paper examines the effects of financial crises on the long memory volatility dependency of daily exchange returns focusing on the Asian crisis in 97-98 and the Global crisis in 08-09. By using the daily KRW-USD and JPY-USD exchange rates which have different trading regions and volumes, this paper first applies both the parametric FIGARCH model and the semi-parametric Local Whittle method to estimate the long memory volatility dependency of the daily returns and the temporally aggregated returns of the two exchange rates. Then it compares the effects of the two financial crises on the long memory volatility dependency of the daily returns. The estimation results reflect that the long memory volatility dependency of the KRW-USD is generally greater than that of the JPY-USD returns and the long memory dependency of the two returns appears to be invariant to temporal aggregation. And, the two financial crises appear to affect the volatility dynamics of all the returns by inducing greater long memory dependency in the volatility process of the exchange returns, but the degree of the effects of the two crises seems to be different on the exchange rates.

The Sites of Memory and Diaspora Memory Constructed in (Jung Da-woon, 2019) (<이타미 준의 바다>에 구성된 기억의 터와 디아스포라 기억)

  • Kang, Seung-Mook
    • The Journal of the Korea Contents Association
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    • v.22 no.10
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    • pp.154-163
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    • 2022
  • This paper tried to examine the implications of the sites of memory and diaspora memory of the life of Jun Itami(Yoo Dong-ryong), a Korean architect in Japan who is interpellated as Zainichi Koreana adopting theoretical and methodological discussions on memory, sites of memory, diaspora, and identity. To this end, the documentary was selected as the subject of analysis. According to the research results, which consists of a total of 48 scenes, is based on the assumption that the sea and Japan and Korea between the sea are the space of memory, and emphasizes that Itami Jun, who had to live as a borderliner and a stranger is disengaged from the borders of nationalities, territories, and countries. In particular, the story of Jun Itami set the sea as a diachronic space(sites of memory) that penetrates the past and present and explores his diaspora identity. The sites of memory of Jun Itami reconstructed in can be said to be a memory space that makes Yoo Dong-ryong more firmly aware of his diaspora identity as a Korean.

Effects of Glycyrrhizae Radix on Repeated Restraint Stress-induced Neurochemical and Behavioral Responses

  • Park, Hyun-Jung;Shim, Hyun-Soo;Kim, Hyun-Young;Kim, Kyung-Soo;Lee, Hye-Jung;Hahm, Dae-Hyun;Shim, In-Sop
    • The Korean Journal of Physiology and Pharmacology
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    • v.14 no.6
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    • pp.371-376
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    • 2010
  • Glycyrrhizae radix (GR) is an herbal medicine that is commonly used in the East Asia for treating a variety of diseases, including stomach disorders. The objective of the present study was to examine the anti-stress effects of GR on repeated stress-induced alterations of anxiety, learning and memory in rats. Restraint stress was administered for 14 days (2 h/day) to the rats in the Control and GR groups (400 mg/kg/day, PO). Starting on the eighth day, the rats were tested for spatial memory on the Morris water maze test (MW) and for anxiety on the elevated plus maze (EPM). We studied the changes of the expressions of cholineacetyl transferase (ChAT) and tyrosine hydroxylase (TH) in the locus coerleus (LC) using immunohistochemistry. The results showed that the rats treated with GR had significantly reduced stress-induced deficits on their learning and memory on the spatial memory tasks. In addition, the ChAT immunoreactivities were increased. Gor the EPM, treatment with GR increased the time spent in the open arms (p<0.001) as compared to that of the control group. Moreover, GR treatment also normalized the increases of the TH expression in the LC (p<0.001). In conclusion, administration of GR improved spatial learning and memory and reduced stress-induced anxiety. Thus, the present results suggest that GR has the potential to attenuate the behavioral and neurochemical impairments caused by stress.

Metabolic changes during adaptation to saline condition and stress memory of Arabidopsis cells

  • Chun, Hyun Jin;Park, Mi Suk;Lee, Su Hyeon;Jin, Byung-Jun;Cho, Hyun Min;Hong, Young-Shick;Kim, Min Chul
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.175-175
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    • 2017
  • To understand molecular mechanisms underlying adaptation of plant cells to saline stress and stress memory, we developed Arabidopsis callus suspension-cultured cells adapted to high salt. Adapted cells to high salt exhibited enhanced tolerance compared to control cells. Moreover, the salt tolerance of adapted cells was stably maintained even after the stress is relieved, indicating that the acquired salt tolerance of adapted cells was memorized. In order to characterize metabolic responses of plant cells during adaptation to high salt stress as well as stress memory, we compared metabolic profiles of salt-adapted and stress-memorized cells with control cells by using NMR spectroscopy. A principle component analysis showed clear metabolic discrimination among control, salt-adapted and stress-memorized cells. Compared with control cells, metabolites related to shikimate metabolism such as tyrosine, and flavonol glycosides, which are related to protective mechanism of plant against stresses were largely up-regulated in adapted cell lines. Moreover, coniferin, a precursor of lignin, was more abundant in salt-adapted cells than control cells. Cell morphology analysis using transmission electron microscopy indicated that cell wall thickness of salt-adapted cells was significantly induced compared to control cells. Consistently, salt adapted cells contained more lignin in their cell walls compared to control cells. The results provide new insight into mechanisms of plant adaptation to saline stress as well as stress memory in metabolic level.

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Krill-Derived Phosphatidylserine Improves TMT-Induced Memory Impairment in the Rat

  • Shim, Hyun-Soo;Park, Hyun-Jung;Ahn, Yong-Ho;Her, Song;Han, Jeong-Jun;Hahm, Dae-Hyun;Lee, Hye-Jung;Shim, In-Sop
    • Biomolecules & Therapeutics
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    • v.20 no.2
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    • pp.207-213
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    • 2012
  • The present study examined the effects of krill-derived phosphatidylserine (Krill-PS) on the learning and memory function and the neural activity in rats with trimethyltin (TMT)-induced memory deficits. The rats were administered vehicle (medium-chain triglyceride: MCT) or Krill-PS (50, 100 mg/kg, p.o.) daily for 21 days. The cognitive improving efficacy of Krill-PS in TMT-induced amnesic rats was investigated by assessing the Morris water maze test and by performing choline acetyltransferase (ChAT), acetylcholinesterase (AChE) and cAMP responsive element binding protein (CREB) immunohistochemistry. The rats with TMT injection showed impaired learning and memory of the tasks and treatment with Krill-PS produced a significant improvement of the escape latency to find the platform in the Morris water maze at the $2^{nd}$ and $4^{th}$ day compared to that of the MCT group (p<0.05). In the retention test, the Krill-PS+MCT groups showed increased time spent around the platform compared to that of the MCT group. Consistent with the behavioral data, Krill-PS 50+MCT group significantly alleviated the loss of acetylcholinergic neurons in the hippocampus and medial septum compared to that of the MCT group. Treatment with Krill-PS significantly increased the CREB positive neurons in the hippocampal CA1 area as compared to that of the MCT group. These results suggest that Krill-PS may be useful for improving the cognitive function via regulation of cholinergic marker enzyme activity and neural activity.

Protective effect of Phellodendri Cortex against lipopolysaccharide-induced memory impairment in rats

  • Lee, Bom-Bi;Sur, Bong-Jun;Cho, Se-Hyung;Yeom, Mi-Jung;Shim, In-Sop;Lee, Hye-Jung;Hahm, Dae-Hyun
    • Animal cells and systems
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    • v.16 no.4
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    • pp.302-312
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    • 2012
  • The purpose of this study was to examine whether Phellodendri Cortex extract (PCE) could improve learning and memory impairments caused by lipopolysaccharide (LPS)-induced inflammation in the rat brain. The effect of PCE on modulating pro-inflammatory mediators in the hippocampus and its underlying mechanism were investigated. Injection of LPS into the lateral ventricle caused acute regional inflammation and subsequent deficits in spatial learning ability in the rats. Daily administration of PCE (50, 100, and 200 mg/kg, i.p.) for 21 days markedly improved the LPS-induced learning and memory disabilities in the Morris water maze and passive avoidance test. PCE administration significantly decreased the expression of pro-inflammatory mediators such as tumor necrosis factor-${\alpha}$, interleukin-$1{\beta}$, and cyclooxygenase-2 mRNA in the hippocampus, as assessed by RT-PCR analysis and immunohistochemistry. Together, these findings suggest that PCE significantly attenuated LPS-induced spatial cognitive impairment through inhibiting the expression of pro-inflammatory mediators in the rat brain. These results suggested that PCE may be effective in preventing or slowing the development of neurological disorders, including Alzheimer's disease, by improving cognitive and memory function because of its anti-inflammation activity in the brain.

Receding Horizon Finite Memory Controls for Output Feedback Controls of Discrete-Time State Space Models

  • Han, Soo-Hee;Kwon, Wook-Hyun
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.1896-1900
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    • 2003
  • In this paper, a new type of output feedback control, called a receding horizon finite memory control (RHFMC), is proposed for stochastic discrete-time state space systems. Constraints such as linearity and finite memory structure with respect to an input and an output, and unbiasedness from the optimal state feedback control are required in advance. The proposed RHFMC is chosen to minimize an optimal criterion with these constraints. The RHFMC is obtained in an explicit closed form using the output and input information on the recent time interval. It is shown that the RHFMC consists of a receding horizon control and an FIR filter. The stability of the RHFMC is investigated for stochastic systems.

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Efficient Signal Reordering Unit Implementation for FFT (FFT를 위한 효율적인 Signal Reordering Unit 구현)

  • Yang, Seung-Won;Lee, Jang-Yeol
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.6
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    • pp.1241-1245
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    • 2009
  • As FFT(Fast Fourier Transform) processor is used in OFDM(Orthogonal Frequency Division Multiplesing) system. According to increase requirement about mobility and broadband, Research about low power and low area FFT processor is needed. So research concern in reduction of memory size and complex multiplier is in progress. Increasing points of FFT increase memory area of FFT processor. Specially, SRU(Signal Reordering Unit) has the most memory in FFT processor. In this paper, we propose a reduced method of memory size of SRU in FFT processor. SRU of 64, 1024 point FFT processor performed implementation by VerilogHDL coding and it verified by simulation. We select the APEX20KE family EP20k1000EPC672-3 device of Altera Corps. SRU implementation is performed by synthesis of Quartus Tool. The bits of data size decide by 24bits that is 12bits from real, imaginary number respectively. It is shown that, the proposed SRU of 64point and 1024point achieve more than 28%, 24% area reduction respectively.