• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.17 no.5
• /
• pp.1503-1515
• /
• 2023

This paper considers the jointly active and passive beamforming design in the IRS-aided MISO downlink vehicle communication system where both V2I and V2V communication paradigms coexist. We formulate the problem as an optimization problem aiming to minimize the total transmit power of the base station subject to SINR requirements of both V2I and V2V users, total transmit power of base station and IRS's phase shift constraints. To deal with this non-convex problem, we propose a method which can alternately optimize the active beamforming at the base station and the passive beamforming at the IRS. By using first-order Taylor expansion, matrix analysis theory and penalized convex-concave process method, the non-convex optimization problem with coupled variables is converted into two decoupled convex sub-problems. The simulation results show that the proposed alternate optimization algorithm can significantly decrease the total transmit power of the vehicle base station.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.838-842
• /
• 2017

The thruster valve, which is one of the key components applied to the mono-propellant system for the satellite, has a circular plate spring structure. It can be designed as a structure that does not have positional deformation and particles by friction and repetitive motion. In this study, finite element analysis and verification were performed by setting the width of the circular plate spring as a design parameter with the material, thickness and radius of the circular plate spring as fixed variables. The linearity of the spring constant is shown by the graph that is spring force with displacement. It is confirmed that the optimization design of the circular plate spring is possible by the spring force tendency according to the total area of circular plate spring.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.34 no.4
• /
• pp.191-200
• /
• 2020

The purpose of this pilot study was to examine the effect of tongue color change due to food ingestion on tongue diagnosis by both Korean Medicine doctors and digital tongue diagnosis system. In order to obtain objective and quantitative data, we used digital camera to collect the data. Prior to our investigation, we conducted a brief survey of 26 Korean Medicine doctors and found out that tongue diagnosis is frequently used and food-stained tongue could be commonly observed in clinics. Depending on their color, viscosity, and amount of intake, various foods caused stains with different colors and thicknesses. Also, duration and amount of food stain on tongue were different from person to person. Since coffee-stained tongue was the most frequently observed one in clinics according to the survey, we used coffee to evaluate the effect of food-stained tongue on tongue diagnosis. Korean Medicine doctors tended to interpret coffee-stained tongue as having yellow tongue coat but their judgement on tongue body color did not differ in spite of the coffee stains. Meanwhile, tongue diagnosis system algorithm tended to judge coffee-stained tongue as having normal but yellowish tongue coat and reddish tongue body. Altogether, food color on tongue can influence tongue diagnosis outcomes. Further research is needed in order to develop more efficient tongue diagnosis algorithm and digital medical service system.

• Nuclear Engineering and Technology
• /
• v.55 no.2
• /
• pp.452-459
• /
• 2023

The core power control is an important issue for the study of dynamic characteristics in China initiative accelerator driven subcritical system (CiADS), which has direct impact on the control strategy and safety analysis process. The CiADS is an experimental facility that is only controlled by the proton beam intensity without considering the control rods in the current engineering design stage. In order to get the optimized operation scheme with the stable and reliable features, the variation of beam intensity using the continuous and periodic control approaches has been adopted, and the change of collimator and the adjusting of duty ratio have been proposed in the power control process. Considering the neutronics and the thermal-hydraulics characteristics in CiADS, the physical model for the core power control has been established by means of the point reactor kinetics method and the lumped parameter method. Moreover, the multi-inputs single-output (MISO) logical structure for the power control process has been constructed using proportional integral derivative (PID) controller, and the meta-heuristic algorithm has been employed to obtain the global optimized parameters for the stable running mode without producing large perturbations. Finally, the verification and validation of the control method have been tested based on the reference scenarios in considering the disturbances of spallation neutron source and inlet temperature respectively, where all the numerical results reveal that the optimization method has satisfactory performance in the CiADS core power control scenarios.

• The Journal of Internal Korean Medicine
• /
• v.44 no.1
• /
• pp.1-11
• /
• 2023

Objective: There are currently no disease-modifying medications or definite long-term sustainable interventions for patients with Parkinson's disease (PD), indicating an unmet treatment need. Our goal was to create a long-term sustainable intervention for PD patients that can be used in Korean medicine clinics. Methods: The Meridian Activation Remedy System (MARS) was created to stimulate a patient's 12 meridians and sinew channels using a combination of acupoint stimulation and exercise. The acupoints and motions used in MARS were selected through literature studies and expert advice. The methodologies were refined using observational and case studies. With slow and fast movements, the MARS intervention was intended to activate both slow- and fast-twitch muscle fibers. Intradermal acupuncture and motion that shift the center of gravity were employed to enhance the patient's balance and proprioception. In addition, the intervention included alternating movement exercises to address the complex cognitive decline commonly occurring in PD patients. Results: The following acupoints were chosen for the MARS intervention: bilateral Hegu (LI4), Houxi (SI3), Waiguan (TE5), Neiguan (PC6), Zhongchong (PC9), Yuji (LU10), Zusanli (ST36), Yanglingquan (GB34), Taichong (LR3), Kunlun (BL60), and Taixi (KI3). We also developed actions that can stimulate the body's 12 meridians. Conclusion: We developed the MARS intervention, which combines acupuncture and exercise, to address the unmet therapeutic needs of PD patients. We hope that with additional research, the MARS intervention can be set as an effective therapeutic program for PD patients.

• Journal of the Korean Society of Physical Medicine
• /
• v.12 no.2
• /
• pp.59-66
• /
• 2017

PURPOSE: The purpose of this study was to determine the effects of postural control training on balance and walking ability in chronic stroke patients. METHODS: Eighteen chronic stroke patients were allocated equally and randomly to an experimental group (n=9) or a control group (n=9). All participants received 60 minutes of comprehensive rehabilitation treatment, the experimental group additionally received a postural control training for 30 minutes, while the control group additionally performed a treadmill training for 30 minutes. These 30-minute training sessions were held five times per week for three weeks. Balance was assessed using Berg balance scale (BBS) and walking ability (gait speed, cadence, step length, and double limb support) was assessed using the GAITRite system. RESULTS: Improvement on all outcome measures was identified from pre-to-post intervention for both groups (p<.05). Post-intervention, there was a significant between-group difference on measured outcomes (p<.05). The experimental group exhibited greater improvement in the gait speed (p=.01; 95% CI .08-.16), cadence (p=.04; 95% CI .34-4.79), step length (p=.02; 95% CI 1.50-5.17), double limb support period (p=.04; 95% CI -2.18 to -.14), and BBS (p=.01; 95% CI 1.04-6.74) compared to the control group. CONCLUSION: The findings of this study suggest that postural control training may be beneficial for improving balance and walking ability of patients with chronic stroke.

• Journal of the Korean Society of Physical Medicine
• /
• v.12 no.2
• /
• pp.75-82
• /
• 2017

PURPOSE: The purpose of this study was to determine the effects of arm training in standing position on balance and walking ability in chronic stroke patients. METHODS: Sixteen chronic stroke patients were allocated equally and randomly to an experimental group (n=8) or a control group (n=8). All participants received 60 minutes of comprehensive rehabilitation treatment, the experimental group additionally received an arm training in standing position for 30 minutes, while the control group additionally performed a treadmill training for 30 minutes. These 30-minute training sessions were held three times per week for six weeks. Upper extremity function was assessed using Fugle-Meyer motor assessment function upper extremity (FMA-UE), balance was assessed using Berg balance scale (BBS), and walking ability (gait speed, cadence, step length, and double limb support period) was assessed using the GAITRite system. RESULTS: Improvement on all outcome measures was identified from pre-to-post intervention for both groups (p<.05). Post-intervention, there was a significant between-group difference on BBS, gait speed, cadence, step length, and double limp support period (p<.05). The experimental group exhibited greater improvement in the BBS (p=.01; z=-2.48), gait speed (p=.01; z=-3.26), cadence (p=.02; z=-2.31), step length (p=.01; z=-3.36), and double limb support period (p=.03; z=-2.84) compared to the control group. CONCLUSION: The findings of this study suggest that arm training in standing position may be beneficial for improving balance and walking ability of patients with chronic stroke.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.12C
• /
• pp.764-773
• /
• 2011

Despite enormous performance gain with multi-antenna transmission in the single cell environment, its gain diminishes out in the multi-cell environment due to interference. It is also very hard to solve the efficient downlink beamforming with low complexity in multi-cell environment. First, this paper shows that the asymptotically sum rate optimal downlink beamformings at low and high SNR are maximum ratio transmit (MRT) and zero forcing (ZF) beamforming in the multi-cell system, respectively. Secondly, exploiting the asymptotically optimal downlink beamforming, we develop simple two types of near optimal downlink beamforming schemes having the form of minimum mean squared error (MMSE) beamforming obtained from the dual uplink problem. For each type, three different subclasses are also considered depending on the computational complexity. The simulation results show that the proposed near optimum algorithms provide the trade-off between the complexity and the performance.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.2
• /
• pp.295-307
• /
• 2021

The Korean Peninsula is surrounded on three sides by the East Sea, West Sea and South Sea which are connected to many rivers and streams, thereby facilitating easy inflow of debris from land. Furthermore, excessive debris inflow to the sea because of active fishing and various recreational activities. Debris entering the sea are weighted over time and settle in the seabed, thus, making direct monitoring of debris impossible and its collection difficult. Uncollected submerged marine debris affects the seabed ecosystem and water quality and can cause ghost fishing and ship accidents, especially due to waste net ropes and waste fishing gears. Therefore, understanding the debris distribution characteristics is necessary to assist quick collection of these debris (waste net ropes and waste fishing gears). Thus, this study conducted a survey of debris deposited in the seas of 39 ports. Furthermore, distribution characteristics and compositions of submerged marine debris were identified by a map prepared through GIS-based spatial analysis of the East Sea. Consequently, 58% of waste tires in the East Sea were concentrated in breakwaters and ship berthing facilities. Moreover, 26 % of waste plastics were distributed outside the port. Identifying the distinct distribution characteristics of submerged marine debris was difficult; however, compared with others, the distribution of waste plastics was possible outside the port. The findings of this study can serve as baseline data to assist the collection of submerged marine debris using the distribution characteristics.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.2D
• /
• pp.275-283
• /
• 2006

Recently, there are increasing needs to provide sufficient information on road signs for expanding cities and traffic networks. Improving efficiency of direction guidance information from road signs not only requires criteria for but also systematic approach to selecting place names that appear on road sings. As such, this paper looks at road direction information from existing road signs that leads to Suwon and investigates whether the current system of road sings provides efficient, systematic and continuous direction information for road users to easily reach their destination. In this paper, Suwon's city hall is set up as the final destination, which is linked from five other cities, Euiwang, Ansan, Hwaseong, Osan and Yongin. The paper attempts to find out whether there is continuity and suitable number of road signs for direction information by analyzing the road signs between these 5 cities and Suwon with respect to direction, direction advance notice and direction guidance. It is found that road users cannot easily find the needed information on their destination from the existing road signs and that continuity of selected place names that systematically appear on road signs is insufficiency. That is to say, the findings of the paper are that while it is easy for road users to find place names that are classified under land marks or the first-class selection of place names on road signs, it is difficult to obtain information from road signs on place names that are grouped under the second or third class. In addition, direction guidance on road signs is problematic, because the appearance frequency of road signs is not adequate and the continuity of road signs is not effective. Moreover, there is insufficient information on local direction guidance for immediate destinations on road signs with respect to turning left or right or going straight. Hence road signs in urban area need systematic improvement to find easily some destination.