• 국제물리치료학회지
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• 제10권2호
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• pp.1768-1773
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• 2019

Background: Aging reduces cognitive abilities, including visual memory (VM) and visual discrimination (VD). Since common cortical networks subserve eye movement and attention, voluntary eye movement may improve visual attention. Visual selective attention was major role for memory, and visual memory and visual attention are intimately related. Objective: To identify the improvement in VD and VM, after implementing the eye movement program consisting of saccadic eye movement (SEM) and pursuit eye movement (PEM) in the institutionalized healthy elderly. Design: Randomized controlled trial. Methods: The study involved a sample of 36 participants, and the mean age was 79.03 years (range 76~84 years). They were randomly allocated to the experimental group (n=16) and control group (n=20). Participants in the experimental group performed SEM 5 times per week for 4 weeks: twice daily at the same time in the morning and afternoon. The program was carried out for 3 minutes, and it consisted of SEM and PEM. The target's moving frequency was set at 0.5 Hz. VM and VD at the baseline and post-intervention were measured using Motor-Free Visual Perception test-4 (MFVPT-4). Results: VM significantly improved in the experimental group (p < .01), and significant differences were observed compared to the control group (p < .01). There was no significant change in VD. Conclusion: The eye movement program consisting of SEM and PEM increased VM more than VD. Therefore, eye movement program was feasible interventions for improving VM in institutionalized elderly persons.

• 대한통합의학회지
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• 제6권4호
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• pp.29-38
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• 2018

Purpose: The purpose of this study was to investigate the psychological symptoms of insomnia, impulsiveness, and memory impairment according to the drinking frequency of college students. Methods: From May 4 to May 17, 2018, a questionnaire survey was conducted for men and women enrolled in J city S university in the Department of Occupational Therapy, Architecture, Social Welfare, and Digital Content. After visiting the department to explain the purpose of the study, 400 questionnaires were distributed to those who agreed to participate in the study. The SPSS 22.0 program was used to analyze the data collected. All statistical analyses were performed at the significance level of 5 %. Results: There is a correlation between alcohol consumption and psychological symptoms, such as insomnia, impulsivity, and memory impairment. As a result of analyzing all departments, insomnia, impulsivity, and memory impairment were the highest in the addiction level. In post-analysis of psychological symptoms, insomnia and impulsiveness had no significant difference, but there was a significant difference in memory impairment (p=.04). Conclusion: Our hope is that this study will help activate programs like preventative education and counseling on alcohol-related psychological symptoms for college students.

• Structural Engineering and Mechanics
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• 제63권4호
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• pp.497-507
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• 2017

During recent earthquakes, a significant number of concrete structures suffered extensive damage. Conventional reinforced concrete structures are designed for life-time safety that may see permanent inelastic deformation after severe earthquakes. Hence, there is a need to utilize adequate materials that have the ability to tolerate large deformation and get back to their original shape. Super-elastic shape memory alloy (SMA) is a smart material with unique properties, such as the ability to regain undeformed shape by unloading or heating. In this research, four different stories (three, five, seven and nine) of reinforced concrete (RC) buildings have been studied and subjected to near-field ground motions. For each building, two different types of reinforcement detailing are considered, including (1) conventional steel reinforcement (RC frame) and (2) steel-SMA reinforcement (SMA RC frame), with SMA bars being used at plastic zones of beams and steel bars in other regions. Nonlinear time history analyses have been performed by "SeismoStruct" finite element software. The results indicate that the application of SMA materials in plastic hinge regions of the beams lead to reduction of the residual displacement and consequently post-earthquake repairs. In general, it can be said that shape memory alloy materials reduce structural damage and retrofit costs.

• Smart Structures and Systems
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• 제5권5호
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• pp.565-585
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• 2009

Superelastic Shape Memory Alloys (SMAs) are gaining acceptance for use as reinforcing bars in concrete structures. The seismic behaviour of concrete frames reinforced with SMAs is being assessed in this study. Two eight-storey concrete frames, one of which is reinforced with regular steel and the other with SMAs at the plastic hinge regions of beams and regular steel elsewhere, are designed and analyzed using 10 different ground motion records. Both frames are located in the highly seismic region of Western Canada and are designed and detailed according to current seismic design standards. The validation of a finite element (FE) program that was conducted previously at the element level is extended to the structure level in this paper using the results of a shake table test of a three-storey moment resisting steel RC frame. The ten accelerograms that are chosen for analyzing the designed RC frames are scaled based on the spectral ordinate at the fundamental periods of the frames. The behaviour of both frames under scaled seismic excitations is compared in terms of maximum inter-storey drift, top-storey drift, inter-storey residual drift, and residual top-storey drift. The results show that SMA-RC frames are able to recover most of its post-yield deformation, even after a strong earthquake.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권6호
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• pp.658-663
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• 2015

In the previous work, we have proposed an integrate-and-fire neuron circuit and synaptic device based on the floating body MOSFET [1-3]. Integrate-and-Fire(I&F) neuron circuit emulates the biological neuron characteristics such as integration, threshold triggering, output generation, refractory period using floating body MOSFET. The synaptic device has short-term and long-term memory in a single silicon device. In this paper, we connect the neuron circuit and the synaptic device using current mirror circuit for summation of post synaptic pulses. We emulate spike-timing-dependent-plasticity (STDP) characteristics of the synapse using feedback voltage without controller or clock. Using memory device in the logic circuit, we can emulate biological synapse and neuron with a small number of devices.

• Asian-Australasian Journal of Animal Sciences
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• 제15권6호
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• pp.900-904
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• 2002

The duration of spatial memory in cattle is potentially important for grazing management. The ability of livestock to remember the location of food patches may lead to uneven range use. In this experiment, how long cattle are able to remember food locations was determined. Six steers were used to conduct this study in a pasture with an 8 row by 8 column grid of 64 plastic containers 5 meters apart. Four randomly chosen containers were loaded with feed pellets. All steers were trained to find the loaded locations until a minimum of empty containers were visited. After this initial training, each steer was tested at 5, 10, 20 and 48 days post-training. Total number of visits (TV), number of containers visited (NC), the ratio of loaded containers (LC) to NC were recorded. Once the steers learned the locations of loaded containers NC did not increase with time since last training up to 48 days (p>0.05). Logarithmic transformation of NC (LNC) was 0.70 and 0.80 for the control and 48 day treatments, respectively. Steers were equally efficient in locating containers with feed. The steers also showed that their ability in locating food was much better than expected by chance (Z>1.62). Findings of the present study do not suggest using spatial memory decay as a tool to promote better grazing distribution. Because steers remembered food locations accurately for at least 48 days.

• 한국통신학회논문지
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• 제38C권6호
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• pp.540-549
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• 2013

본 논문에서는 멀티 레벨 셀 낸드 플래시 메모리에서 연판정 에러 정정을 위한 적응적 비균일 양자화기를 제안한다. 기존의 최대 상호 정보(maximum mutual information) 양자화기는 최적의 연판정 에러 정정 성능을 보이지만, 소모적인 탐색(exhaustive search)으로 인하여 많은 계산량을 요구한다. 본 논문에서 제안된 양자화기는 최대 여섯 개의 파라미터로 표현되는 간단한 구조를 갖고 있어 연산량이 적다. 또한 제안된 양자화기는 쓰기 심볼과 읽기 심볼 사이의 상호 정보를 최대화하는 방향으로 파라미터 값의 최적화시키므로, 최대 상호 정보 양자화기에 근접하는 우수한 연판정 에러 정정 성능을 보인다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제11권2호
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• pp.73-79
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• 2011

This paper describes a reset-free delay-locked loop (DLL) for a memory controller application, with the aid of a hysteresis coarse lock detector. The coarse lock loop in the proposed DLL adjusts the delay between input and output clock within the pull-in range of the main loop phase detector. In addition, it monitors the main loop's lock status by dividing the input clock and counting its multiphase edges. Moreover, by using hysteresis, it controls the coarse lock range, thus reduces jitter. The proposed DLL neither suffers from harmonic lock and stuck problems nor needs an external reset or start-up signal. In a 0.13-${\mu}m$ CMOS process, post-layout simulation demonstrates that, even with a switching supply noise, the peak-to-peak jitter is less than 30 ps over the operating range of 500-1200 MHz. It occupies 0.04 $mm^2$ and dissipates 16.6 mW at 1.2 GHz.

• Smart Structures and Systems
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• 제24권4호
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• pp.491-506
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• 2019

Literature regarding concrete walls reinforced by super elastic shape memory alloy (SMA) bars is rather limited. The seismic behavior of a system concurrently including a distinct steel reinforced concrete (RC) wall, as well as another wall reinforced by super elastic SMA at the first story, and steel rebar at upper stories, would be an interesting matter. In this paper, the seismic response of such a COMBINED system is compared to a conventional system with steel RC concrete walls (STEEL-Rein.) and also to a wall system with SMA rebar at the first story and steel rebar at other stories ( SMA-Rein.). Nonlinear time history analysis at maximum considered earthquake (MCE) and design bases earthquake (DBE) levels is conducted and the main responses like maximum inter-story drift ratio and residual inter-story drift ratio are investigated. Furthermore, incremental dynamic analysis is used to accomplish probabilistic seismic studies by creating fragility curves. Results demonstrated that the SMA-Rein. system, subjected to DBE and MCE ground motions, has almost zero and 0.27% residual maximum inter-story drifts, while the values for the COMBINED system are 0.25% and 0.51%. Furthermore, fragility curves show that using SMA rebar at the base of all walls causes a larger probability of exceedance 3% inter-story drift limit state compared to the COMBINED system. Static push over analysis demonstrated that the strength of the COMBINED model is almost 0.35% larger than that of the two other models, and its general post-yielding stiffness is also approximately twice the corresponding stiffness of the two other models.

• Smart Structures and Systems
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• 제7권5호
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• pp.329-348
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• 2011

Large-scale earthquakes pose serious threats to infrastructure causing substantial damage and large residual deformations. Superelastic (SE) Shape-Memory-Alloys (SMAs) are unique alloys with the ability to undergo large deformations, but can recover its original shape upon stress removal. The purpose of this research is to exploit this characteristic of SMAs such that concrete Beam-Column Joints (BCJs) reinforced with SMA bars at the plastic hinge region experience reduced residual deformation at the end of earthquakes. Another objective is to evaluate the seismic performance of SMA Reinforced Concrete BCJs repaired with flowable Structural-Repair-Concrete (SRC). A $\frac{3}{4}$-scale BCJ reinforced with SMA rebars in the plastic-hinge zone was tested under reversed cyclic loading, and subsequently repaired and retested. The joint was selected from an RC building located in the seismic region of western Canada. It was designed and detailed according to the NBCC 2005 and CSA A23.3-04 recommendations. The behaviour under reversed cyclic loading of the original and repaired joints, their load-storey drift, and energy dissipation ability were compared. The results demonstrate that SMA-RC BCJs are able to recover nearly all of their post-yield deformation, requiring a minimum amount of repair, even after a large earthquake, proving to be smart structural elements. It was also shown that the use of SRC to repair damaged BCJs can restore its full capacity.