• 제목/요약/키워드: memory function

검색결과 1,183건 처리시간 0.026초

Bootstrap methods for long-memory processes: a review

  • Kim, Young Min;Kim, Yongku
    • Communications for Statistical Applications and Methods
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    • 제24권1호
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    • pp.1-13
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    • 2017
  • This manuscript summarized advances in bootstrap methods for long-range dependent time series data. The stationary linear long-memory process is briefly described, which is a target process for bootstrap methodologies on time-domain and frequency-domain in this review. We illustrate time-domain bootstrap under long-range dependence, moving or non-overlapping block bootstraps, and the autoregressive-sieve bootstrap. In particular, block bootstrap methodologies need an adjustment factor for the distribution estimation of the sample mean in contrast to applications to weak dependent time processes. However, the autoregressive-sieve bootstrap does not need any other modification for application to long-memory. The frequency domain bootstrap for Whittle estimation is provided using parametric spectral density estimates because there is no current nonparametric spectral density estimation method using a kernel function for the linear long-range dependent time process.

Synthetic bio-actuators and their applications in biomedicine

  • Neiman, Veronica J.;Varghese, Shyni
    • Smart Structures and Systems
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    • 제7권3호
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    • pp.185-198
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    • 2011
  • The promise of biomimetic smart structures that can function as sensors and actuators in biomedicine is enormous. Technological development in the field of stimuli-responsive shape memory polymers have opened up a new avenue of applications for polymer-based synthetic actuators. Such synthetic actuators mimic various attributes of living organisms including responsiveness to stimuli, shape memory, selectivity, motility, and organization. This article briefly reviews various stimuli-responsive shape memory polymers and their application as bioactuators. Although the technological advancements have prototyped the potential applications of these smart materials, their widespread commercialization depends on many factors such as sensitivity, versatility, moldability, robustness, and cost.

지능(知能)에 관(關)한 동서의학적(東西醫學的) 고찰(考察) (Review of Intelligence and Memory)

  • 서영민;김장현
    • 대한한방소아과학회지
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    • 제13권1호
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    • pp.139-166
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    • 1999
  • The purpose of this review is to determine oriental concept of intelligence and memory, and to minimize adverse effect during treatment of brain disease by western medicine. Intelligence is developed by interaction between genetic factor ane environmental factor in Western medicine, Wherease mental function is difined by 'Chilsin' or 'Ohsin', and brain which control intelligence and memory is define by part of heart in oriental medicine The conception that mind and body are sameone may show possibility of intelligence and memory enhancement, and it may be usefule to clinical application.

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인지적 접근을 이용한 언어중재가 전도성 실어증자의 언어 표현력에 미치는 영향: 사례 연구 (The Effects of Cognitive Language Intervention in a Subject with Conduction Aphasia: Case Study)

  • 이옥분;권영주;정옥란
    • 음성과학
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    • 제8권4호
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    • pp.119-129
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    • 2001
  • Language is one aspect of cognition, along with attention and concentration, learning and memory, visuospatial abilities, and executive function. The purpose of this study was to determine the effect of language intervention by cognitive approach on language expressive performance in a patient with conduction aphasia. This study used several tasks such as Attention and concentration task, visual memory tasks, memory tasks, categorization, divergent thinking, self-monitoring and evaluate thinking. The effects of treatment were evaluated by periodic probing of both trained and untrained familiar words in three tasks; picture naming, answering to questions and telling stories. The results showed improvements both in trained and untrained words. Therefore, we concluded that expressive language performance of this aphasic patient is amenable to this intervention, and that cognitive therapy approach can be useful.

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수학적 사고에 동원되는 두뇌 영역들과 이의 교육학적 의미 (Mathematical thinking, its neural systems and implication for education)

  • 김연미
    • 한국수학교육학회지시리즈A:수학교육
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    • 제52권1호
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    • pp.19-41
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    • 2013
  • What is the foundation of mathematical thinking? Is it logic based symbolic language system? or does it rely more on mental imagery and visuo-spatial abilities? What kind of neural changes happen if someone's mathematical abilities improve through practice? To answer these questions, basic cognitive processes including long term memory, working memory, visuo-spatial perception, number processes are considered through neuropsychological outcomes. Neuronal changes following development and practices are inspected and we can show there are neural networks critical for the mathematical thinking and development: prefrontal-anterior cingulate-parietal network. Through these inquiry, we can infer the answer to our question.

자기진단과 시계 기능을 갖는 비동기용 불휘발성 메모리 모듈의 설계 (Design of Asynchronous Nonvolatile Memory Module with Self-diagnosis and Clock Function)

  • 신우현;이강원;양오
    • 반도체디스플레이기술학회지
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    • 제22권1호
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    • pp.43-48
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    • 2023
  • This paper discusses the design of 32Mbyte asynchronous nonvolatile memory modules, which includes self-diagnosis and RTC (Real Time Clock) functions to enhance their data stability and reliability. Nonvolatile memory modules can maintain data even in a power-off state, thereby improving the stability and reliability of a system or device. However, due to the possibility of data error due to electrical or physical reasons, additional data loss prevention methods are required. To minimize data error in asynchronous nonvolatile memory modules, this paper proposes the use of voltage monitoring circuits, self-diagnosis, BBT (Bad Block Table), ECC (Error Correction Code), CRC (Cyclic Redundancy Check)32, and data check sum, data recording method using RTC. Prototypes have been produced to confirm correct operation and suggest the possibility of commercialization.

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Effect of Hfe Deficiency on Memory Capacity and Motor Coordination after Manganese Exposure by Drinking Water in Mice

  • Alsulimani, Helal Hussain;Ye, Qi;Kim, Jonghan
    • Toxicological Research
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    • 제31권4호
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    • pp.347-354
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    • 2015
  • Excess manganese (Mn) is neurotoxic. Increased manganese stores in the brain are associated with a number of behavioral problems, including motor dysfunction, memory loss and psychiatric disorders. We previously showed that the transport and neurotoxicity of manganese after intranasal instillation of the metal are altered in Hfe-deficient mice, a mouse model of the iron overload disorder hereditary hemochromatosis (HH). However, it is not fully understood whether loss of Hfe function modifies Mn neurotoxicity after ingestion. To investigate the role of Hfe in oral Mn toxicity, we exposed Hfe-knockout ($Hfe^{-/-}$) and their control wild-type ($Hfe^{+/+}$) mice to $MnCl_2$ in drinking water (5 mg/mL) for 5 weeks. Motor coordination and spatial memory capacity were determined by the rotarod test and the Barnes maze test, respectively. Brain and liver metal levels were analyzed by inductively coupled plasma mass spectrometry. Compared with the water-drinking group, mice drinking Mn significantly increased Mn concentrations in the liver and brain of both genotypes. Mn exposure decreased iron levels in the liver, but not in the brain. Neither Mn nor Hfe deficiency altered tissue concentrations of copper or zinc. The rotarod test showed that Mn exposure decreased motor skills in $Hfe^{+/+}$ mice, but not in $Hfe^{-/-}$ mice (p = 0.023). In the Barns maze test, latency to find the target hole was not altered in Mn-exposed $Hfe^{+/+}$ compared with water-drinking $Hfe^{+/+}$ mice. However, Mn-exposed $Hfe^{-/-}$ mice spent more time to find the target hole than Mn-drinking $Hfe^{+/+}$ mice (p = 0.028). These data indicate that loss of Hfe function impairs spatial memory upon Mn exposure in drinking water. Our results suggest that individuals with hemochromatosis could be more vulnerable to memory deficits induced by Mn ingestion from our environment. The pathophysiological role of HFE in manganese neurotoxicity should be carefully examined in patients with HFE-associated hemochromatosis and other iron overload disorders.

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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    • 제20권2호
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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.

한국영화에 표현된 회색의 기능과 의미 : 기억과 망각 (Function and Meaning of Color Gray in Korean Films : Memory and Oblivion)

  • 김종국
    • Journal of Information Technology Applications and Management
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    • 제28권3호
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    • pp.77-87
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    • 2021
  • The color gray in the cinema expresses the private or public memory and oblivion in the reminiscence scenes. The aesthetic function and meaning of gray that interacts with other elements in cinematic time and space are expanded in various ways. This study was analyzed the cases in which gray was used as the main visual style by limiting the scope to Korean films. Based on the traditional cultural symbolic meaning of gray, I analyzed how it was applied and transformed in films, and interpreted the cultural-social meaning by the interaction between gray and other elements. In film history starting from monochrome, gray has been used as a visual device suitable for realizing cinematic or imaginary reality. Gray is adopted when dreams or recollections are visualized as imaginary reality, and it is used when dreamy imaginations of daydreaming are demonstrated. Gray, which reproduces the dreamlike reality of imagination, is the concrete and realistic way of expression. First, in Korean films, gray is a flashback visual device that recalls the past, and is an intermediary visual form that materializes the imaginary. In films such as Ode to My Father (2014), DongJu (2015), A Resistance(2019) and The Battle : Roar to Victory (2019), the gray of the past is a visual device for cultural memory that builds the homogeneity and identity of the group. In the era of hyper-visibility, gray in black and white images is intended to be clearly remembered by unfamiliarity rather than blurry oblivion by familiarity. Second, in genre films with disaster materials such as Train To Busan (2016) and Ashfall (2019), the grays of rain, fog, clouds, shadows and smoke highlight other elements, and the gray color causes anxiety and fear. In war films such as TaeGukGi: Brotherhood Of War (2003) and The Front Line (2011), gray shows a more intense brutality than the primary color. In sports films such as 4th Place (2015), Take Off (2009) and Forever The Moment (2007), gray expresses uncertainty and immaturity. Third, gray visualizes the historical memory of A Petal (1996), the oblivion in Oh! My Gran (2020) and Poetry (2010), and the reality of daydreaming Gagman (1988) and Dream (1990). At the boundary between imagination and reality, gray is a visual form of dreams, memories and forgetfulness.

동적 기호 실행을 이용한 힙 메모리 OOB 취약점 자동 탐지 방법 (Automated Method for Detecting OOB Vulnerability of Heap Memory Using Dynamic Symbolic Execution)

  • 강상용;박성현;노봉남
    • 정보보호학회논문지
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    • 제28권4호
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    • pp.919-928
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    • 2018
  • OOB(Out-Of-Bounds)는 힙 메모리에서 발생하는 취약점 중 가장 강력한 취약점 중 하나이다. OOB 취약점을 이용하면 Array의 길이를 속여 해당 길이만큼의 메모리를 읽기 혹은 쓰기가 가능하기 때문에 공격자는 기밀 정보에 대한 무단 액세스를 악용할 수 있다. 본 논문에서는 동적 기호 실행과 쉐도우 메모리 테이블을 활용하여 힙 메모리에서 발생하는 OOB 취약점을 자동으로 탐지하는 방법을 제안한다. 먼저, 힙 메모리 할당 및 해제 함수 후킹을 통해 쉐도우 메모리 테이블을 구축한다. 이후 메모리 액세스가 발생할 때, 쉐도우 메모리를 참조하여 OOB가 발생할 수 있는지를 판단하고, 발생 가능성이 존재할 경우 크래시를 유발하는 테스트케이스를 자동으로 생성한다. 제안하는 방법을 활용할 경우, 취약한 블록 탐색에 성공한다면 반드시 OOB를 유발하는 테스트케이스를 생성할 수 있다. 뿐만 아니라 전통적인 동적 기호 실행과는 다르게 명확한 목표 지점을 설정하지 않더라도 취약점 탐색이 가능하다.