• 제목/요약/키워드: memory effect function

검색결과 255건 처리시간 0.036초

Study on Fast-Changing Mixed-Modulation Recognition Based on Neural Network Algorithms

  • Jing, Qingfeng;Wang, Huaxia;Yang, Liming
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제14권12호
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    • pp.4664-4681
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    • 2020
  • Modulation recognition (MR) plays a key role in cognitive radar, cognitive radio, and some other civilian and military fields. While existing methods can identify the signal modulation type by extracting the signal characteristics, the quality of feature extraction has a serious impact on the recognition results. In this paper, an end-to-end MR method based on long short-term memory (LSTM) and the gated recurrent unit (GRU) is put forward, which can directly predict the modulation type from a sampled signal. Additionally, the sliding window method is applied to fast-changing mixed-modulation signals for which the signal modulation type changes over time. The recognition accuracy on training datasets in different SNR ranges and the proportion of each modulation method in misclassified samples are analyzed, and it is found to be reasonable to select the evenly-distributed and full range of SNR data as the training data. With the improvement of the SNR, the recognition accuracy increases rapidly. When the length of the training dataset increases, the neural network recognition effect is better. The loss function value of the neural network decreases with the increase of the training dataset length, and then tends to be stable. Moreover, when the fast-changing period is less than 20ms, the error rate is as high as 50%. As the fast-changing period is increased to 30ms, the error rates of the GRU and LSTM neural networks are less than 5%.

Novel Cultivation of six-year-old Korean Ginseng (Panax ginseng) in pot: From Non-Agrochemical Management to Increased Ginsenoside

  • Kyung Ho Hwang;Hyun Gi Kim;Kiyoung Jang;Yong Ju Kim
    • Journal of Ginseng Research
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    • 제48권1호
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    • pp.98-102
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    • 2024
  • Background: Ginseng (Panax ginseng Meyer) is a perennial plant belonging to the Araliaceae family that is known to have various beneficial effects including improving memory loss and spatial cognitive ability, and anti-cancer and anti-diabetes activity. Its functional benefits also include improving liver function, regulating blood pressure, stress, and providing antioxidant activity. Usually, various agrochemicals are used in cultivating ginseng preventing from many diseases. Methods: FCGP (field cultivated ginseng in pot) was implemented by imitating MCWG (mountain cultivated wild ginseng). Pesticide analysis of pot cultivation was carried out and the contents of bioactive components such as ginsenoside were also analyzed. Results: FCGP ginsenoside content was higher than that of FCG (field cultivated ginseng) and MCWG. FCGP has been shown to have a relatively high antioxidant effect compared with cultivated ginseng. Conclusion: It was confirmed that ginseng can be grown for 6 years without resorting to use of pesticides. In addition, it was confirmed that effective accumulation of physiologically active ingredients such as ginsenoside is possible. Our result represents FCGP is a novel method of pesticide-free ginseng cultivation

Hybrid MBE Growth of Crack-Free GaN Layers on Si (110) Substrates

  • 박철현;오재응;노영균;이상태;김문덕
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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    • pp.183-184
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    • 2013
  • Two main MBE growth techniques have been used: plasma-assisted MBE (PA-MBE), which utilizes a rf plasma to supply active nitrogen, and ammonia MBE, in which nitrogen is supplied by pyrolysis of NH3 on the sample surface during growth. PA-MBE is typically performed under metal-rich growth conditions, which results in the formation of gallium droplets on the sample surface and a narrow range of conditions for optimal growth. In contrast, high-quality GaN films can be grown by ammonia MBE under an excess nitrogen flux, which in principle should result in improved device uniformity due to the elimination of droplets and wider range of stable growth conditions. A drawback of ammonia MBE, on the other hand, is a serious memory effect of NH3 condensed on the cryo-panels and the vicinity of heaters, which ruins the control of critical growth stages, i.e. the native oxide desorption and the surface reconstruction, and the accurate control of V/III ratio, especially in the initial stage of seed layer growth. In this paper, we demonstrate that the reliable and reproducible growth of GaN on Si (110) substrates is successfully achieved by combining two MBE growth technologies using rf plasma and ammonia and setting a proper growth protocol. Samples were grown in a MBE system equipped with both a nitrogen rf plasma source (SVT) and an ammonia source. The ammonia gas purity was >99.9999% and further purified by using a getter filter. The custom-made injector designed to focus the ammonia flux onto the substrate was used for the gas delivery, while aluminum and gallium were provided via conventional effusion cells. The growth sequence to minimize the residual ammonia and subsequent memory effects is the following: (1) Native oxides are desorbed at $750^{\circ}C$ (Fig. (a) for [$1^-10$] and [001] azimuth) (2) 40 nm thick AlN is first grown using nitrogen rf plasma source at $900^{\circ}C$ nder the optimized condition to maintain the layer by layer growth of AlN buffer layer and slightly Al-rich condition. (Fig. (b)) (3) After switching to ammonia source, GaN growth is initiated with different V/III ratio and temperature conditions. A streaky RHEED pattern with an appearance of a weak ($2{\times}2$) reconstruction characteristic of Ga-polarity is observed all along the growth of subsequent GaN layer under optimized conditions. (Fig. (c)) The structural properties as well as dislocation densities as a function of growth conditions have been investigated using symmetrical and asymmetrical x-ray rocking curves. The electrical characteristics as a function of buffer and GaN layer growth conditions as well as the growth sequence will be also discussed. Figure: (a) RHEED pattern after oxide desorption (b) after 40 nm thick AlN growth using nitrogen rf plasma source and (c) after 600 nm thick GaN growth using ammonia source for (upper) [110] and (lower) [001] azimuth.

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Actinidia arguta Sprout as a Natural Antioxidant: Ameliorating Effect on Lipopolysaccharide-Induced Cognitive Impairment

  • Kang, Jeong Eun;Park, Seon Kyeong;Kang, Jin Yong;Kim, Jong Min;Kwon, Bong Seok;Park, Sang Hyun;Lee, Chang Jun;Yoo, Seul Ki;Heo, Ho Jin
    • Journal of Microbiology and Biotechnology
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    • 제31권1호
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    • pp.51-62
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    • 2021
  • Here, we investigated the prebiotic and antioxidant effects of Actinidia arguta sprout water extract (AASWE) on lipopolysaccharide (LPS)-induced cognitive deficit mice. AASWE increased viable cell count, titratable acidity, and acetic acid production in Lactobacillus reuteri strain and showed a cytoprotective effect on LPS-induced inflammation in HT-29 cells. We assessed the behavior of LPS-induced cognitive deficit mice using Y-maze, passive avoidance and Morris water maze tests and found that administration of AASWE significantly improved learning and memory function. The AASWE group showed antioxidant activity through downregulation of malondialdehyde levels and upregulation of superoxide dismutase levels in brain tissue. In addition, the AASWE group exhibited activation of the cholinergic system with decreased acetylcholinesterase activity in brain tissue. Furthermore, AASWE effectively downregulated inflammatory mediators such as phosphorylated-JNK, phosphorylated-NF-κB, TNF-α and interleukin-6. The major bioactive compounds of AASWE were identified as quercetin-3-O-arabinopyranosyl(1→2)-rhamnopyranosyl(1→6)-glucopyranose, quercetin-3-O-apiosyl(1 → 2)-galactoside, rutin, and 3-caffeoylquinic acid. Based on these results, we suggest that AASWE not only increases the growth of beneficial bacteria in the intestines, but also shows an ameliorating effect on LPS-induced cognitive impairment.

해부 실습 시 포름알데히드 노출이 학생들의 신경행동기능에 미치는 영향 (The effect of formaldehyde on neurobehavioral performance of student during cadaver dissection)

  • 사공용;조희윤;이인국;이경수;전만중
    • Journal of Yeungnam Medical Science
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    • 제33권2호
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    • pp.85-89
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    • 2016
  • Background: Formaldehyde is used to preserve cadaver in medical schools, and students are exposed to formaldehyde during cadaver dissection classes. When humans are exposed to formaldehyde, it induces mucosal inflammation, skin inflammation, and declining of neurobehavioral function including attention and memory executive functions. The purpose of this study is to identify the effects of formaldehyde exposure on student's neurobehavioral performance during cadaver dissection classes. Methods: The level of formaldehyde was measured in a cadaver dissection class. A total of 16 students were randomly divided into two groups. One group wore respiratory protection masks, while the other group did not. Among many subtests in Korean Computerized Neurobehavioral test, backward digit span was tested on all subjects before and after the class. Results: The length of memorized digit span between the two groups was not significant; however there was a greater decrease in neurobehavioral function after formaldehyde exposure in the non-mask group than the mask group. Conclusion: Formaldehyde exposure during cadaver dissection may likely decrease neurobehavioral performance of students. Therefore, proper ventilation system and respiratory protective equipment are necessary to protect medical school students from adverse effects of formaldehyde exposure.

리치미디어 컨텐츠 구현에 있어 상호작용 모델 (A Study on the Characteristic of Interaction Model for Implementation of Richmedia Contents)

  • 김민수
    • 디자인학연구
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    • 제17권1호
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    • pp.201-210
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    • 2004
  • 기호 통합 텍스트로서 웹은 "정보"라는 무형의 지식개념을 위한 핵심적 플랫폼으로 전 세계에 걸쳐 유비쿼터스 환경을 기반으로 광범위한 소통모델로 발전하고 있다. 이러한 소통과정의 파악은 정보구조 조직화시 필수불가결한 요소로 늘어만 가는 정보의 양적 팽창과 더불어 컨텐츠 질을 결정 하는데 주요한 기준으로 작용되어질 수 있다. 본 연구는 공학적, 언어학적 모델을 기반으로 웹 사이트내에서 리치미디어 컨텐츠들의 형태, 기능, 감성적 측면을 중심으로 컨텐츠 조직화시 어떠한 방식으로 의미적 소통을 행하는지 그 추이과정을 분석하였다. 이를 토대로 웹 공간에서 이루어지는 사용자들의 접근요소에서 인터페이스 최종 귀착지까지의 과정을 통해 그 변화과정을 소통모델로 재인하고 그 과정 중에 나타나는 정보기능에 중점을 두어 고찰하였다. 방법적인 측면으로 쉐논과 웨버 모델의 기능특성과 야콥슨 모델의 네 가지 기능(교감, 지시, 시적, 메타언어적)을 중심으로 정보 소통 시 웹 컨텐츠에 적용되어질 수 있는지에 관하여 그 가능성의 도출 작업을 수행한다. 웹이라는 신지형의 구조에서 속도, 저장 공간, 압축기술, 정보여과 과정과 같은 새로운 개념들은 의사소통의 채널로 작용하는 웹이 표현되어지는 컨텐츠의 양식 변화에 많은 부분 영향을 미침으로써 컨텐츠 표현에 있어 통합매체의 소통환경을 파악하는 것은 컨텐츠 조직화시 정보를 효율적으로 운용할 수 있는 기틀이 마련될 것이다.

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일상생활활동 훈련이 뇌졸중 환자의 시지각 기능에 미치는 효과 (The Effect of Activities of Daily Living(ADL) Training on the Visual Perception Capacity Performance Function of the Stroke)

  • 김지원;김미영;황보선;장철
    • 대한통합의학회지
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    • 제2권1호
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    • pp.1-14
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    • 2014
  • Purpose : The aim of this study was to investigate Activities of Daily Living(ADL) function recovery of repeated measurement of stroke who received ADL training. Method : Twenty stroke patients were treated by ADL program therapy from May to June. All of in twenty stroke patients, 10 stroke patients take part in Occupational Therapy and 10 stroke patients take part in ADL training for 30 min five times a week during four weeks in M- hospital occupational Therapy treatment room, local in Changwon and Geoje. We used two assessment on is Motor Free Visual Perception Test-Third Edition(MVPT-3) for visual perception the other is Modified Barthel Index(MBI) for ADL. Result : First, Visual Short Term Memory(VSTM) score was changed statistical significance OT intervention group than compare with ADL training group(p<.05). Second, Visaul Closure(VC) score was changed statistical significance OT intervention group than compare with ADL training group(p<.05). Third, Spatial Orientation(SO) score was changed statistical significance OT intervention group than compare with ADL training group(p<.05). The fourth Motor Free Visual Perception Test-Third Edition(MVPT-3) score was changed statistical significance OT intervention group than compare with ADL training group(p<.05). The fifth Modified Barthel Index(MBI total) score was changed statistical significance OT intervention group than compare with ADL training group(p<.05). Conclusion : Therefore, ADL training can be on method the visual perception of stroke patients.

N-3계 지방산 적절 함량 식이의 docosahexaenoic acid 첨가가 기억력 관련 뇌 기능에 미치는 영향 (Effect of Treatment with Docosahexaenoic Acid into N-3 Fatty Acid Adequate Diet on Learning Related Brain Function in Rat)

  • 임선영
    • 생명과학회지
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    • 제19권7호
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    • pp.917-922
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    • 2009
  • SD계 흰쥐를 사용하여 motor activity 실험에서 동물들의 자발적인 운동성을 측정한 결과, 주어진 시간 내 움직인 시간과 움직인 거리에는 n-3 지방산이 적절히 함유된 식이군 (Adq group)과 DHA가 첨가된 식이군(Adq+DHA group)간에 유의적 차이를 관찰할 수가 없었다. 학습효과 실험에서 n-3 지방산이 적절히 함유된 식이군 (Adq group)의 경우 목적 플랫트폼까지 걸리는 시간이 DHA 첨가 식이군(Adq+DHA group)에 비하여 다소 길었으나 유의적 차이는 관찰할 수가 없었다. 수영 속도(swimming speed)에서 DHA 첨가 식이군(Adq+DHA group)의 경우, n-3 지방산이 적절히 함유된 식이군 (Adq group)에 비해 유의적으로 빨랐으나 수영 풀에서 움직인 거리 (swimming distance)에는 두 식이군 간의 유의적 차이가 없었다. 두 식이군의 흰쥐들이 수영한 시간(swimming time)과 쉬고 있는 시간(resting time)의 경우, 쉬는 시간에는 유의적 차이가 없었으나 수영 시간 또한 n-3 지방산이 적절이 함유된 식이(Adq group)로 사육된 쥐가 DHA가 첨가된 식이로 사육된 쥐(Adq+DHA group)보다 수영한 시간이 길었으나 여기서도 유의적 차이는 없었다. 기억력 테스트에서 n-3 지방산이 적절히 함유된 식이군(Adq group) 및 DHA가 첨가된 식이군(Adq+DHA group) 모두는 목적 플랫트폼이 있었던 A 지역에 대한 기억이 우수하여 다른 지역들인 B, C, D를 지나가는 횟수보다 유의적으로 많았음을 관찰하였다(p<0.05). 이상의 결과로부터 임신에서부터 성인이 될 때까지 n-3 지방산이 적절히 함유된 식이로 사육된 쥐와 비교할 때 DHA가 첨가된 식이로 사육된 흰쥐가 Morris water maze를 이용한 공간기억력 실험에서 다소 우수한 기억 학습효과를 나타내었으나 유의적 차이는 없었음을 관찰 할 수가 있었다.

인지재활 영역에서 가상현실 (Virtual Reality in Cognitive Rehabilitation)

  • 박인지;박흥석;김태훈
    • 재활치료과학
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    • 제1권1호
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    • pp.29-38
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    • 2012
  • 서론 : 본 연구는 인지재활의 주요영역인 실행 장애, 기억력 장애, 지각 장애, 주의력 장애, 일상생활활동 영역에서의 가상현실의 적용 사례를 문헌고찰 함으로써, 작업치료 적용을 위한 기초자료로 활용하고자 한다. 본론 : 가상현실을 바탕으로 한 인지프로그램은 평가 뿐 만이 아니라 전반적인 인지 요소의 훈련용으로 사용되어지고 있다. 가상현실을 이용한 인지 프로그램은 실제 환경에서의 평가이자 훈련이기에 기존 컴퓨터에 기초한 평가 및 훈련과 비교하여 실제 환경으로 전이효과가 큰 것으로 밝혀지고 있다. 가상현실의 재활 프로그램에 적용은 최신 기술의 발전과 더불어 보다 큰 발전을 가져올 것으로 예상되며, 이는 곧 혁신적인 치료 기술의 발전을 가져 올 수 있다. 이 과정에 가상현실은 미래에 보다 많이 연구 되어질 것으로 예상되며, 특히 인지영역에서 가상현실은 기존의 평가들 보다 향상된 실제 환경으로의 전이효과에 주목할 필요가 있다. 결론 : 인지영역에서 가상현실의 적용은 무한한 잠재력을 가지고 있으며, 평가 뿐 만 아니라 훈련이 통합된 재활 프로그램으로 활용도가 광범위 할 것으로 기대된다.

Electroacupuncture Analgesia Is Improved by Adenoviral Gene Transfer of Dopamine Beta-hydroxylase into the Hypothalamus of Rats

  • Kim, Soo-Jeong;Chung, Eun Sook;Lee, Jun-Ho;Lee, Chang Hoon;Kim, Sun Kwang;Lee, Hye-Jung;Bae, Hyunsu
    • The Korean Journal of Physiology and Pharmacology
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    • 제17권6호
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    • pp.505-510
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    • 2013
  • Electroacupuncture (EA) is a modified form of acupuncture that utilizes electrical stimulation. We previously showed that EA stimulated rats were divided into responders that were sensitive to EA and non-responders that were insensitive to EA based on the tail flick latency (TFL) test. The dopamine beta-hydroxylase (DBH) gene was more abundantly expressed in the hypothalamus of responder rats than non-responder rats. To determine whether overexpression of DBH gene expression in the hypothalamus modulate EA analgesia, we constructed a DBH encoding adenovirus and which was then injected into the hypothalamus of SD rats. Microinjection of DBH or control GFP virus into the hypothalamus had no changes on the basal pain threshold measured by a TFL test without EA treatment. However, the analgesic effect of EA was significantly enhanced from seven days after microinjection of the DBH virus, but not after injection of the control GFP virus. DBH expression was significantly higher in the hypothalamus of DBH virus injected rat than control GFP virus or PBS injected rats. Moreover, expression of the DBH gene did not affect the body core temperature, body weight, motor function or learning and memory ability. Although the functional role of DBH in the hypothalamus in the analgesic effect of EA remains unclear, our findings suggest that expression of the DBH gene in the hypothalamus promotes EA analgesia without obvious side-effects.