• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1055-1060
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• 2009

Noise is one of the major environmental problems in human life. But hot water distributers with the flow rate control valve bring about often noise according to the heating control condition in residential buildings. The sound power level increased as the flow rate and pressure difference increased. And thus, experimental analyses for the flow rate control and the pressure difference control were carried out in this study to reduce the noise emitted from the flow rate control valve. As the results, the flow rate control method using a SMA(Shape Memory Alloy)-valve and the flow rate control system using a pressure difference sensor can be expected to control noise in the region of below 50 dB of sound power level.

• ETRI Journal
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• 제32권3호
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• pp.380-389
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• 2010

This paper presents a new edge-protection algorithm and its very large scale integration (VLSI) architecture for block artifact reduction. Unlike previous approaches using block classification, our algorithm utilizes pixel classification to categorize each pixel into one of two classes, namely smooth region and edge region, which are described by the edge-protection maps. Based on these maps, a two-step adaptive filter which includes offset filtering and edge-preserving filtering is used to remove block artifacts. A pipelined VLSI architecture of the proposed deblocking algorithm for HD video processing is also presented in this paper. A memory-reduced architecture for a block buffer is used to optimize memory usage. The architecture of the proposed deblocking filter is verified on FPGA Cyclone II and implemented using the ANAM 0.25 ${\mu}m$ CMOS cell library. Our experimental results show that our proposed algorithm effectively reduces block artifacts while preserving the details. The PSNR performance of our algorithm using pixel classification is better than that of previous algorithms using block classification.

• Earthquakes and Structures
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• 제4권6호
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• pp.607-627
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• 2013

The application of shape memory alloys (SMAs) to the seismic response reduction of civil engineering structures has attracted growing interest due to their self-centering feature and excellent fatigue performance. The loading rate dependence of SMAs raises a concern in the seismic analysis of SMA-based devices. However, the implementation of micromechanics-based strain-rate-dependent constitutive models in structural analysis software is rather complicated and computationally demanding. This paper investigates the feasibility of replacing complex rate-dependent models with rate-independent constitutive models for superelastic SMA elements in seismic time-history analysis. Three uniaxial constitutive models for superelastic SMAs, including one rate-dependent thermomechanical model and two rate-independent phenomenological models, are considered in this comparative study. The pros and cons of the three nonlinear constitutive models are also discussed. A parametric study of single-degree-of-freedom systems with different initial periods and strength reduction factors is conducted to examine the effect of the three constitutive models on seismic simulations. Additionally, nonlinear time-history analyses of a three-story prototype steel frame building with special SMA-based damping braces are performed. Two suites of seismic records that correspond to frequent and design basis earthquakes are used as base excitations in the seismic analyses of steel-braced frames. The results of this study show that the rate-independent constitutive models, with their parameters properly tuned to dynamic test data, are able to predict the seismic responses of structures with SMA-based seismic response modification devices.

• 전기전자학회논문지
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• 제21권2호
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• pp.136-141
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• 2017

본 논문에서는 딥러닝을 PC에 적용하기 위한 메모리 최적화에 관한 알고리즘을 제안한다. 제안된 알고리즘은 일반 PC에서 기존의 딥러닝 구조에서 요구되는 연산처리 과정과 데이터 량을 감소시켜 메모리 및 연산처리 시간을 최소화한다. 본 논문에서 제안하는 알고리즘은 분별력이 있는 랜덤 필터를 이용한 컨볼루션 층 구성 과정, PCA를 이용한 데이터 축소 과정, SVM을 사용한 CNN 구조 생성 등의 3과정으로 이루어진다. 분별력이 있는 랜덤 필터를 이용한 컨볼루션 층 구성 과정에서는 학습과정이 필요치 않아서 전체적인 딥러닝의 학습시간을 단축시킨다. PCA를 이용한 데이터 축소 과정에서는 메모리량과 연산처리량을 감소시킨다. SVM을 사용한 CNN 구조 생성에서는 필요로 하는 메모리량과 연산 처리량의 감소 효과를 극대화 시킨다. 제안된 알고리즘의 성능을 평가하기 위하여 예일 대학교의 Extended Yale B 얼굴 데이터베이스를 사용하여 실험한 결과, 본 논문에서 제안하는 알고리즘이 기존의 CNN 알고리즘과 비교하여 비슷한 성능의 인식률을 보이면서 연산 소요시간과 메모리 점유율에 있어 우수함이 확인되었다. 본 논문에서 제안한 알고리즘을 바탕으로 하여 일반 PC에서도 많은 데이터와 연산처리를 가진 딥러닝 알고리즘을 구현할 수 있으리라 기대된다.

• 대한전자공학회논문지SD
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• 제47권3호
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• pp.7-17
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• 2010

본 논문은 4-트랜지스터 래치 셀을 이용한 저전력향 신개념의 SRAM을 제안한다. 4-트랜지스터 메모리 셀은 종래의 6-트랜지스터 SRAM 셀에서 access 트랜지스터를 제거한 형태로, PMOS 트랜지스터의 소스는 비트라인 쌍에 연결되고 NMOS 트랜지스터의 소스는 두개의 워드라인에 각각 연결된다. 동작시 워드라인에 일정크기의 전압을 인가할 때 비트라인에 흐르는 전류를 감지하여 읽기동작을 수행하고, 비트라인 쌍에 전압차이를 두고 워드라인에 일정크기의 전압을 인가하여 쓰기동작을 수행한다. 이는 공급전압 보다 낮은 소신호 전압으로 워드라인과 비트라인을 구동하여 메모리 셀의 데이터를 저장하고 읽어낼 수 있어서 동작 소비전력이 적다. 아울러 셀 누셀전류 경로의 감소로 인해 대기 소모전력 또한 개선되는 장점이 있다. 0.18-${\mu}m$ CMOS 공정으로 1.8-V, 16-kbit SRAM test chip을 제작하여 제안한 회로기술을 검증하였고, 칩 면적은 $0.2156\;mm^2$이며 access 속도는 17.5 ns 이다. 동일한 환경에서 구현한 종래의 6-트랜지스터 SRAM과 비교하여 읽기동작시 30% 쓰기동작시 42% 동작소비전력이 적고, 대기전력 또한 64% 적게 소비함을 관찰하였다.

• 대한한의학방제학회지
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• 제25권1호
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• pp.69-87
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• 2017

Objectives : Cheongnoemyeongsin-hwan (CNMSH) is a herb medicine to treat cognitive impairment. This study was investigated the effects of CNMSH on learning and memory impairment induced by cerebral hypoperfusion. Cerebral hypoperfusion was produced chronically by permanent bilateral common carotid artery occlusion (BCCAO) in rats. Methods : CNMSH was administered orally once a day (250 mg/kg) for 28 days starting at 4th week after the BCCAO. The acquisition of learning and the retention of memory were tested on 9th week after the BCCAO using the Morris water maze. In addition, effect of CNMSH on neuronal apoptosis and ${\beta}-amyloid$ accumulation in the hippocmapus was evaluated with immunohistochemistry and Western blotting. Results : 1. CNMSH and ChAL significantly shortened the escape latencies on the 2nd day of acquisition training trials. 2. ChAL significantly prolonged the swimming time spent in the target and peri-target zones and CNMSH also significantly prolonged the swimming time spent in the peri-target zone. 3. CNMSH and ChAL significantly increased the number of target heading in the retention test. 4. ChAL significantly shortened the time of the 1st target heading in the retention test, but CNMSH insignificantly shortened the time of that. 5. CNMSH and ChAL significantly increased the memory score in the retention test. 6. CNMSH and ChAL significantly attenuated the reduction of CA1 neurons, but insignificantly attenuated the reduction of CA1 thickness. 7. CNMSH and ChAL significantly attenuated the up-regulation of Bax expression in the CA1 of hippocampus. 8. CNMSH and ChAL significantly attenuated the up-regulation of cascapse-3 expression in the CA1 of hippocampus. 9. CNMSH and ChAL significantly attenuated the ${\beta}-amyloid$ accumulation in the CA1 of hippocampus. 10. CNMSH and ChAL significantly attenuated the up-regulation of APP expression in the CA1 of hippocampus. 11. CNMSH and ChAL significantly attenuated the up-regulation of BACE-1 expression in the CA1 of hippocampus. Conclusions : The results show that CNMSH attenuates neuronal apoptosis and ${\beta}-amyloid$ accumulation in the hippocampus and alleviates the impairment of learning and memory produced by chronic cerebral hypoperfusion. These results suggest that CNMSH may be a beneficial medicinal herb to treat cognitive impairment associated with neurodegenerative diseases.

• 동의생리병리학회지
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• 제17권1호
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• pp.50-56
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• 2003

This research was done to make the effective prescription and cope with various senile dementia. So Sprague-Dawley rats were injected with ibotenate to make a damage on learning and memory functions. At first acquisition test and retention rest were done in the Morris water maze. And to evaluate the effects of the sample drug(TBM) on choline acetyltranferase and acetylcholine esterase, immunoreactive measurement and enzymatic activity measuring were carried out. The ibotenic acid were injected to hippocampus CA1 and CA3 area. The results were as following. TBM improved the learning ability in the acquisition test and memory function in the retention test significantly. And TBM increased the level of ChAT which is synthesizing acetylcholine in CA3 area, and at the same time it increased the level of AChE which is resolving acetylcholine. These results show that T8M improved the cholinergic catabolism and anabolism, and the increment of metabolic activity of cholinergic system. In other words, it contributes to the recovery of damaged learning and memory function by ibotenic acid. So it can be concluded that TBM will be helpful to cholinergic brain damage induced by primary or senile reduction of acetylcholine secretive activity.

• 대한전자공학회논문지SD
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• 제39권2호
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• pp.7-13
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• 2002

USB 카메라를 이용하여 PC 화상 회의를 할 때 image sensor에서 읽어드린 동화상을 USB를 통해서 PC로 전송하게 되는데 이 때 USB의 전송 속도의 제한 때문에 동화상의 압축이 필요하다. 동화상의 압축을 위해서는 많은 양의 메모리가 필요하므로 외부 메모리를 사용하는 것이 일반적이다. 동화상 압축 알고리즘은 여러 가지가 있지만 JPEG을 사용할 경우 동화상 프레임을 모두 저장할 필요는 없으며, JPEG 압축 엔진으로 일정한 속도로 들어오는 데이터와, JPEG에서 사용되는 데이터의, 순서의 불일치를 해결해주는JPEG 입력 버퍼만이 필요하다. JPEG 입력 버퍼는 읽고 쓰는 순서가 차이가 많이 나므로 double buffering을 사용하는 것이 일반적이지만 이 논문에서는 double buffering을 사용하지 않고 칩 안에 내장 되는데 문제가 없는 적은 메모리 요구량으로 구현하는 방법을 제안한다. 제안된 메모리 아키텍처를 사용하면 별도의 외부 메모리가 필요하지 않으므로 부품 감소에 의한 전체적인 비용 절감이 가능하다.

• The Korean Journal of Physiology and Pharmacology
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• 제8권4호
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• pp.173-179
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• 2004

Amyloid ${\beta}-peptide\;(A{\beta})$ contributes to the pathogenesis of Alzheimer's disease (AD), causing neuronal death through apoptosis. In this study, the neuroprotective role of BF-7, extracted form sericultural product, was examined against $A{\beta}-induced$ toxicity in cultured human neuronal cell SKN-SH. In order to know if the BF-7 has positive role on the cognition and memory in human, the mixture of BF-7, DHA and EPA (BDE) was examined using Rey Kim and K-WAIS test with 50 healthy high school student. We report here that BDE significantly attenuated $A{\beta}-induced$ apoptosis through the reduction of ROS accumulation, and diminished caspase-like protease activity. Moreover, the memory index and memory preservation, and attentative concentration of BDE treated group for 1 month were significantly improved, in contrast to the case of placebo control treated with DHA and EPA. This result represent that the BF-7 play significant positive role on learning memory. Taken together, our result suggested the natural product BF-7 is a good substance for the brain functionally and physiologically.

• 대한통합의학회지
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• 제1권3호
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• pp.79-95
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• 2013

Purpose : This study aims to investigate the effect of the Snoezelen and Rehacom programs on improvement of attention and memory, and the effect of the Snoezelen program on stress reduction. Method : This study was targeted at 11 subjects in the Snoezelen experimental group, 11 subjects in the Rehacom group and 11 subjects in the non-experimental group. As the initial evaluation, all the subjects took electroencephalography. Then, the Snoezelen group and Rehacom group did Snoezelen training and Rehacom training, respectively total 12 times(for 20 minutes twice per week for six weeks), but no training was applied to the control group. Three weeks after the training, the interim was carried out, and four weeks after the training, the final evaluation was carried out. Results : Subjects' attention increased to $58.15{\pm}4.96$ from $43.75{\pm}4.69$ during the Snoezelen training, and increased to $49.85{\pm}1.91$ from $43.28{\pm}2.71$ during the Rehacom training, which means the Snoezelen training was more effective in improving attention(P<0.05). Subjects' memory increased to $56.14{\pm}1.26$ from $43.19{\pm}3.46$ during the Snoezelen training, and increased to $50.94{\pm}4.0$ from $43.07{\pm}2.58$ during the Rehacom training. This also implies that the Snoezelen training was more effective in improving memory(P<0.05). Conclusion : Though both of the Snoezelen training and Rehacom training improved attention and memory, the Snoezelen program was more effective, and it also influenced stress resistance and physical arousal.