• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.486-490
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• 2008

본 논문에서는 Spurious NAK Suppression알고리즘을 통하여 RLP의 성능향상에 대한 기법을 제안한다. 일반적으로, Hybrid ARQ기법에서는 MAC과 Physical Layer에서의 Retransmission 및 Error Correction으로 무선환경에서의 Error를 줄이고 latency를 보장하고 있다. 그러나 Hybrid ARQ에서의 Multiple SAW나 Selective-ARQ에 의해서 인접한 Packet들 간의 out-of-sequence문제가 발생할 수 밖에 없으며, upper layer인 RLP(혹은 RLC)에서는 이를 re-sequencing하여야 하는 부담감이 생기게 된다. 본 논문에서는 RLP receiver에서의 re-sequencing방법에 있어서, 효율적으로 RLP-NAK의 전송시점을 결정하는 NAK suppression 방법을 제안하고 있으며, 실험을 통하여 높은 성능향상을 보임을 확인할 수 있다.

• Journal of information and communication convergence engineering
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• v.2 no.3
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• pp.139-144
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• 2004

In order to transmit various types of multimedia data (i.e. voice, video, and data) over a wireless channel, the coding and modulation scheme needs to be flexible and capable of providing a variable quality of service, data rates, and latency. In this paper, we study a mobile multimedia COMA network combined with the concatenated Reed-Solomon/Rate Compatible Punctured Convolution code (RS/RCPC). Also, this paper propose the combination of concatenated RS/RCPC coder and COMA RAKE receiver for multimedia COMA traffic which can be sent over wireless channels. From the results, using a frequency selective Rayleigh fading channel model, it is shown that concatenated RS/RCPC coder at the wireless physical layer can be effective in providing reliable wireless multimedia CDMA network. And the proposed scheme that combine concatenated RS/RCPC coder and CDMA RAKE receiver provides a significant gain in the BER performance over multi-user interference and multipath frequency selective fading channels.

• International Journal of Computer Science & Network Security
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• v.22 no.6
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• pp.83-90
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• 2022

Traditional Cloud Computing would be unable to safely host IoT data due to its high latency as the number of IoT sensors and physical devices accommodated on the Internet grows by the day. Because of the difficulty of processing all IoT large data on Cloud facilities, there hasn't been enough research done on automating the security of all components in the IoT-Cloud ecosystem that deal with big data and real-time jobs. It's difficult, for example, to build an automatic, secure data transfer from the IoT layer to the cloud layer, which incorporates a large number of scattered devices. Addressing this issue this article presents an intelligent algorithm that deals with enhancing security aspects in IoT cloud ecosystem using butterfly optimization algorithm.

• Journal of information and communication convergence engineering
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• v.21 no.1
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• pp.24-31
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• 2023

The solid-state drive (SSD) possesses higher input and output speeds, more resistance to physical shock, and lower latency compared with regular hard disks; hence, it is an increasingly popular storage device. However, tiny components on an internal printed circuit board (PCB) hinder the manual detection of malfunctioning components. With the rapid development of artificial intelligence technologies, automatic detection of components through convolutional neural networks (CNN) can provide a sound solution for this area. This study proposes applying the YOLOv5 model to SSD PCB component detection, which is the first step in detecting defective components. It achieves pioneering state-of-the-art results on the SSD PCB dataset. Contrast experiments are conducted with YOLOX, a neck-and-neck model with YOLOv5; evidently, YOLOv5 obtains an mAP@0.5 of 99.0%, essentially outperforming YOLOX. These experiments prove that the YOLOv5 model is effective for tiny object detection and can be used to study the second step of detecting defective components in the future.

• Science of Emotion and Sensibility
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• v.20 no.4
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• pp.41-54
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• 2017

Physical activity has positive effects on cognitive functions by aging. However, it is rare to find research that have scientifically investigated the effects on the affective-cognitive function. Thus, this study aims to brain-scientifically research its effects of physical activity on the affective-cognitive function of adults in adolescence and senescence. As subjects of this study, a total of 60 males adults in D region were selected, and then equally divided into four groups of young exercise group(25~35y/o), young non-exercise group(26~35y/o), old exercise group(60~70y/o), and old non-exercise group(60~70y/o). As experiment tools, the EEG measuring equipment and International Affective Picture System(IAPS) were used. The experiment of this study used an affective-cognitive task where subjects pressed a button depending on emotional valence(positive, neutral, negative) shown in the pictures. During the task, EEG measured eight areas(Fp1, Fp2, Fz, C3, C4, Cz, T3, T4) out of brain areas in accordance with the international 10-20 electrode system, EEG was measured. For statistical analysis, a three-way ANOVA on $4(group){\times}3(stimulus){\times}8(area)$ was conducted. The results showed main effects of group in both reaction time and accuracy, and also in the latency of P3. And there was an interaction between group and stimulus the amplitude of P3. In conclusion, Physical activity has positive effects on the affective-cognitive function of people in adolescence and senescence.

• Journal of Magnetics
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• v.19 no.1
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• pp.28-31
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• 2014

The aim of the present study was to examine whether mirror therapy, in conjunction with repetitive transcranial magnetic stimulation (rTMS), can improve the upper extremity function of stroke patient. This study was conducted with 35 subjects, who were diagnosed as a hemiparesis by stroke. The Mirror plus rTMS group was of 12 members who undertook mirror therapy in conjunction with rTMS, the Mirror group was of 11 members who undertook mirror therapy, and the control group was of 12 members who undertook sham therapy. A motor cortex excitability was performed by motor evoked potential, and upper limb function was evaluated by Fugl-Meyer Assessment, and Box and Block Test. Significant difference was shown after the experiment, in comparison of the groups in terms of latency, and as the result of post hoc test, significant difference was shown between the Mirror plus rTMS group and control group, and between the Mirror group and control group, respectively. Significant difference was shown after the experiment in comparison of the groups in amplitude, and as the result of post hoc test, significant difference was shown between the Mirror plus rTMS group and Mirror group, and between the Mirror plus rTMS group and control group. Significant difference was shown after the experiment, in comparison of the groups in FMA and BBT, and as the result of post hoc test, significant difference was shown between the Mirror plus rTMS group and Mirror group, and between the Mirror group and control group. The study showed that mirror therapy in conjunction with rTMS is more effective to improve upper extremity function, than mirror therapy and sham therapy.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.5 no.2
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• pp.11-21
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• 2007

The purpose of this study were to investigate influence of heat stress temperature on sympathetic nerve activities. Subjects were 8 normal adults (4 men, 4 women, 21.36 years old). First sympathetic nerve activities were measured at the point that increase of core temperature stops at the state of applying normal thermic temperature (NIT; $34^{\circ}C$). After measurement, temperature of bathtub was increased to heat stress temperature (HST; $46^{\circ}C$) and sympathetic nerve activities were remeasured at the point that temperature increase stops. Sympathetic skin response (SSR) were analyzed using EMG, IR thermometer, and auto stethoscope. SSR latency showed significant differences at both palms by electrical stimulation to median nerve (p<.05). Electrical stimulation to forehead showed significant difference at left palm (p<.05) and electrical stimulation to navel showed significant difference at right palm (p<.05). Median nerve in changes of SSR amplitude showed significant differences at both palms in HST (p<.01). Electrical stimulation to navel showed significant difference at left palm (p<.05). Ts of forehead and xiphoid process showed significant differences (p<0.01). Tc of oral (p<0.05) and inner ear (p<0.01) showed significant differences. Pulse rate showed significant difference (<0.05). This study showed that immersion in HST had significant decrease of excitability in sympathetic nervous system compared to immersion in NTT.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.2
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• pp.43-52
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• 2021

Purpose : Chronic neck pain negatively impacts the quality of life and causes various problems in daily life due to pain, insomnia, and sleep disturbances in patients with this condition. Therapeutic interventions to solve these problems in rehabilitation and physical therapy are being introduced; however, the evidence of the efficacy of myofascial release (MFR) is still insufficient. This study aimed to investigate the effects of applying MFR on pain, insomnia, and sleep disturbances in patients with chronic neck pain. Methods : Ten patients with chronic neck pain were randomly selected and grouped into the experimental group (n₁ = 10) and control group (n₂ = 10) by cross-over design. Pain was measured before and after MFR intervention. Moreover, insomnia was measured only after MFR intervention. Polysomnography was performed after MFR intervention. Wilcoxon signed rank test and Mann-Whitney U test were used for the visual analog scale (VAS). Independent sample t-test was separately performed to measure insomnia and sleep. Results : After MFR intervention, the VAS score of the experimental group (p = 0.005) significantly decreased than that of the control group (p = 0.002). The insomnia score of the experimental group significantly decreased than that of the control group (p = 0.001). The total sleep time (p = 0.001), sleep efficiency (p = 0.001), and sleep latency (p = 0.001) of the experimental group significantly increased than those of the control group in the polysomnographic measurement. Conclusion : The application of MFR of the neck and upper trunk may have a positive effect on pain, insomnia, and sleep disturbances in patients with chronic neck pain. It was also suggested that an objective and quantitative polysomnography can be used more often in the field of rehabilitation and physical therapy.

• Research in Community and Public Health Nursing
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• v.33 no.4
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• pp.396-407
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• 2022

Purpose: The purpose of this study was to assess insomnia and the quality of sleep, investigate the concordance between objective and self-report sleep patterns, and identify physiological, psychological, and situational factors influencing insomnia and sleep quality among firefighters. Methods: A descriptive, cross-sectional study was conducted with 103 firefighters in Korea. The collected data were analyzed using SPSS 23.0. Descriptive statistics, the independent t-test, and hierarchical logistic regression analysis were performed. Results: Insomnia was found in 66 (64.1 %) of the total subjects, and the average quality of sleep (PSQI) was 5.65 (SD=2.57). Total sleep time (401.00 minutes) and sleep latency (21.60 minutes) measured using self-reported scales were longer than the ones measured using objective measurements by approximately 48.70 and 17.10 minutes, respectively. Factors related to insomnia included the role as a paramedic (OR=4.28, 95% CI: 1.02~17.92), anxiety (OR=1.12, 95% CI: 1.01~1.24), and sedentary lifestyle (OR=0.85, 95% CI: 0.78~0.94), and factors related to sleep quality were physical illness status (OR=5.17, 95% CI: 1.53~17.51) and social support (OR=0.86, 95% CI: 0.78~0.95). Conclusion: The results show a high prevalence of insomnia, poor quality of sleep and the discrepancy between objective and subjective sleep patterns among firefighters. To promote sleep quality and health, early screening and treatment of anxiety and physical illness are required. It is necessary to conduct further studies examining the relationship between physical activity level and sleep.

• The KIPS Transactions:PartA
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• v.11A no.1
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• pp.49-56
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• 2004

The performance of the multiprocessor systems is limited by the several factors. The system performance is affected by the processor speed, memory delay, and interconnection network bandwidth/latency. By the evolution of semiconductor technology, off the shelf microprocessor speed breaks beyond GHz, and the processors can be scalable up to multiprocessor system by connecting through the interconnection networks. In this situation, the system performances are bound by the latencies and the bandwidth of the interconnection networks. SCI, Myrinet, and Gigabit Ethernet are widely adopted as a high-speed interconnection network links for the high performance cluster systems. Performance improvement of the interconnection network can be achieved by the bandwidth extension and the latency minimization. Speed up of the operation clock speed is a simple way to accomplish the bandwidth and latency betterment, while its physical distance makes the difficulties to attain the high frequency clock. Hence the system performance and scalability suffered from the interconnection network limitation. Duplicating the link of the interconnection network is one of the solutions to resolve the bottleneck of the scalable systems. Dual-ring SCI link structure is an example of the interconnection network improvement. In this paper, I propose a network topology and a transaction path algorism, which optimize the latency and the efficiency under the duplicated links. By the simulation results, the proposed structure shows 1.05 to 1.11 times better latency, and exhibits 1.42 to 2.1 times faster execution compared to the dual ring systems.