• Journal of Digital Contents Society
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• v.19 no.8
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• pp.1585-1592
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• 2018

Due to un-balancing weight allocation on the wheelchair the existing wheelchair system are faced with the risk of flipping or falling when a wheelchair goes up to a hill. In to order to be safer during riding the wheelchair, in this paper, we proposed a real-time new solution using the integrated Gyro Sensor and Tilt Sensor for controlling the balance. Because the typical property of wheelchair is for the special user who meets the difficulty in moving on foot the maintain the balance of wheel-chair systems have become important and helpful. In our method, we calculate the seat angle using information from Tilt Sensor. However, due to the law of inertia when a wheelchair is moving there is a deviation in the output value of Tilt Sensor. Therefore, we have to optimize the value of the angle by utilizing the acceleration that is the output of the Gyro Sensor. We took the advantages by using the combination of Gyro and Tilt sensors. Moreover, we also solved the consumption issue of the whole system. Through various experimentations with usage of ZigBee sensor module, the power consumption for the balancing system is reduced significantly.

• Health Policy and Management
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• v.30 no.2
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• pp.185-191
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• 2020

Background: From January 2018, a policy was applied to differentially apply the co-payment for medical expenses of 15,000 won or more from 30% to 10%-30% for each medical fee. This policy lowers the burden on the medical use of the elderly, and it is necessary to analyze the effect of the policy by confirming changes in medical use and supply behavior after 2 years. Methods: The National Health Insurance Service's national medical use database was used. As for the analysis method, first, the medical use and medical supply behavior change over the age of 65 years were confirmed, and second, in order to check the net effect of the policy, the 66-year-old as the experimental group and the 63-year-old as the control group were selected as the control group. The propensity score matching was performed using the variables of age, living alone, income quartile, residence, disability, chronic disease, and co-morbid disease scores, and then it was analyzed using the difference in difference analysis method. Results: The share of the number of treatments under 15,000 won decreased from 37.0% in 2017 to 20.2% in 2018, while the share of the number of treatments under 15,001-20,000 won increased from 8.0% to 22.7%. It was confirmed that the reason for the increase in the cost of treatment per treatment was the result of the increase in the amount of physical therapy and examination. As a result of the policy effect, the burden of co-payment per person was reduced, and as a result, the number of hospital visits per person and the total medical cost per person increased. Conclusion: The self-pay rate differential policy reduced the burden of medical expenses for the elderly and confirmed the increase in medical use. However, the interpretation of the increase in medical use was not able to distinguish whether the unsatisfactory medical care was satisfied or the inducement demand. Efficient allocation of resources is a more important point in the future when the super-aged society is in front. It is necessary to prepare a plan to induce rational medical use within a range that does not impair the medical accessibility of the elderly.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.7
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• pp.1797-1806
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• 1998

Future satellite communication systems will be developed at Ka-band (20/30 GHz) owing to the relatively wide frequency allocation and current freedom from terrestrial interference for multimedia services. A serious disadvantage of the Ka-band, however, is the very high atmospheric attenuation in rainy weather. Synchronous CDMA drastically redces the effect of self-noise with several interesting features of CDMA for mobile communications such as fixible freuqncy rese, the capability of performin soft-handover and a lower sensitivity to interference. This paper evaluates the performance of a synchronous CDMA reture link for a Ka-band geostationary satellite communication system. For a fixed satellite channel whose characteristics depend on weather conditions, the signal envelope and phase for this channel is modelled as Gaussian. The bit error and outage probability, and the detection loss due to imperfect chip timing synchronization is analytically evaluated and the system capacity degaradation due to the weather condition is estimated. The two cases consist of the general case in which all users are affected by rain condition, and the worst case in which the reference user is only affected by rain attenuation. the results for two cases of rain condition clearly show that synchronous CDMA eases the power control requirements and has less sensitivity to imperfect power control.

• Journal of Korea Water Resources Association
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• v.31 no.6
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• pp.727-739
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• 1998

The main objectives o reservoir optimal operation can be described as follows : maximization of the benefits through optimal allocation of the limited water resources for various purpose; minimization of t도 costs by the flood damage in potential damaging regions and risk of dam failure, etc. through safe drainage of a bulky volume of excessive water by a proper reservoir operation. Reviewing the past research works related to reservoir operation, we can find that the study on the matter of the former has been extensively carried out in last decades rather than the matter of the latter. This study is focused on developing a methodology of optimal reservoir operation for flood control, and a case study is performed on the Chungju multipurpose reservoir in Korea. The final goal of the study is to establish a reservoir optimal operation system which can search optimal policy to compromise two conflicting objectives: downstream flood damage and dam safety-upstream flood damage. In order to reach the final goal of the study, the following items were studied : (1)validation of hydrological data using HYMOS: (2)establishment of a downstream flood routing model coupling a rainfall-runoff model and SOBEK system for 1-D hydrodynamic flood routing; (3)replication of a flood damage estimation model by a neural network; (4)development of an integrated reservoir optimization module for an optimal operation policy.

• Spatial Information Research
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• v.22 no.5
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• pp.65-75
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• 2014

Bus headway plays an important role not only in determining the passenger waiting time and bus service quality, but also in influencing the bus operation cost and passenger demand. Previous research on headway control has considered only an hourly difference in the distribution of ridership between peak and non-peak hours. However, this approach is too simple to help manage ridership demand fluctuations in a short time scale; thus passengers' waiting cost will be generated when ridership demand exceeds the supply of bus services. Moreover, bus ridership demand varies by station location and traffic situation. To address this concern, we propose a headway control algorithm for minimizing the waiting time cost by using Smart Card data. We also provide proof of the convergence of the algorithm to the desired headway allocation using a set of preconditions of political waiting time guarantees and available fleet constraints. For model verification, the data from the No. 143 bus line in Seoul were used. The results show that the total savings in cost totaled approximately 600,000 won per day when we apply the time-value cost of waiting time. Thus, we can expect that cost savings will be more pronounced when the algorithm is applied to larger systems.

• Journal of Acupuncture Research
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• v.23 no.5
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• pp.127-144
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• 2006

Background and Purpose : Though there were many clinical studies of acupuncture effects they didn't have appropriate control group. So we didn't say it was true acupuncture effect, though subjects in clinical study improved. To investigate the possibility of sham acupuncture application, we examined how well subjects distinguished real acupuncture from sham acupuncture. Methods : We investigate the possibility of sham acupuncture application as the following 3 kinds of methods. 1. The public (n=60) and Oriental Medicine Doctors (n=20) looked at the appearance of acupuncture and then were treated with randomly allocated acupuncture and judged it as real or sham. 2. The public (n=60) and Oriental Medicine doctors (n=20) were treated with randomly allocated acupuncture, then they looked at the appearance of acupuncture and judged it as real or sham. 3. The public (n=60) were treated with randomly allocated acupuncture (right-real-left-sham), (right-sham-left-real), (left-real-right-sham), (left-sham-right-real), then they judged it as real or sham. Results : 1. When the public (n=60) looked at the acupuncture appearance, the correct judgement ratio was 63.3%. After they were treated with acupuncture, the correct judgement ratio was 50.0%. 2. When Oriental Medicine doctors (n=20) looked at the acupuncture appearance, the correct judgement ratio was 25.0%. After they were treated with acupuncture, the correct judgement ratio was 45.0%. 3. When the public (n=60) were treated with acupuncture, the correct judgement ratio was 50.0%. After they looked at the acupuncture appearance, the correct judgement ratio was 63.3%. 4. When Oriental Medicine doctors (n=20) were treated with acupuncture, the correct judgement ratio was 65.5%. After they looked at the acupuncture appearance, the correct judgement ratio was 65.0%. 5. After the public (n=60) were treated with randomly allocated sham or real acupuncture as (right-real-left-sham), (right-sham-left-real), (left-real-right-sham), or (left-sham-right-real). the correct judgement ratio was 66.7% in looking at the acupuncture appearance group, and in not looking at 60.0%. Conclusion : These results indicated that Kim Sham Acupuncture could apply to the double blind clinical study of acupuncture effect. And more continuous studies are needed on Sham Acupuncture apparatus.

• Journal of KIISE:Information Networking
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• v.29 no.4
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• pp.375-385
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• 2002

The IETF has defined the Intserv model and the RSVP signaling protocol to improve QoS capability for a set of newly emerging services including voice and video streams that require high transmission bandwidth and low delay. However, since the current Intserv model requires each router to maintain the states of each service flow, the complexity and the overhead for processing packets in each rioter drastically increase as the size of the network increases, giving rise to the scalability problem. This motivates our work; namely, we investigate and devise new control schemes to enhance the scalability of the Intesev model. To do this, we basically resort to the SCORE network model, extend it to fairly well adapt to the three services presented in the Intserv model, and devise schemes of the QoS scheduling, the admission control, and the edge and core node architectures. We also carry out the computer simulation by using ns-2 simulator to examine the performance of the proposed scheme in respects of the bandwidth allocation capability, the packet delay, and the packet delay variation. The results show that the proposed scheme meets the QoS requirements of the respective three services of Intserv model, thus we conclude that the proposed scheme enhances the scalability, while keeping the efficiency of the current Intserv model.

• The Korean Journal of Applied Statistics
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• v.34 no.5
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• pp.795-806
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• 2021

Recently, as text data through online channels have become vast, there is a growing interest in research that summarizes and analyzes them. One of the fundamental analyses of text data is to extract potential topics. Although the researcher may read all the data and summarize the contents one by one, it is not easy to deal with large amounts of data. Blei and Lafferty (2007) and Blei et al. (2003) proposed topic modeling methods for extracting topics using a statistical model. Since the text data is generally collected over time, it is worthwhile to monitor the topic's changes. In this study, we propose a topic index based on the results of the topic model. In addition, a control chart, a representative tool for statistical process management, is applied to monitor the topic index over time. As a practical example, we use text data collected from Blue House National Petition boards between March 5, 2018, and March 5, 2020.

• Journal of the Korea Society of Computer and Information
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• v.27 no.5
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• pp.215-224
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• 2022

The purpose of this study is to analyze how it affects functional movement and dynamic balance applying Czech get up exercise based on the principle of motor development of child for office worker women in 30s and 40s. Through random allocation, an Czech get up exercise group(n=15) and a control group(n=14) were formed to apply exercise for 12 weeks, 3 times a week, and 60 minutes a day, and the control group maintained daily life at the same period. As a result of the study, showed that Deep squat(p<.05), Hurdle step(p<.01), In-line lunge(p<.05), Trunk stability push-up(p<.001), Rotary stability (p<.01), Total score(p<.001), were significantly in the Czech get up Group, and Dynamic Balance of Lower Extremity(p<.001), Right Dynamic Balance of Lower Extremity(p<.001) were also significantly in the Czech get up Group. In conclusion, it is thought that Czech get up exercise based on the principle of motor development of child will have a positive effect on the functional movement and dynamic balance in office women, thereby increasing work efficiency as well as healthy life.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2021.11a
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• pp.78-80
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• 2021

This study is based on Degree of Recognition and AHP surveys for experts, this study investigates changes in the demand of seafarers in response to changes in the shipping industry environment in which Maritime Autonomous Surface Ships(MASS) emerge according to the application of the fourth industrial revolution technology to ships, and it looks into changes in seafarers' skills. It also analyzes and proposes a plan for cultivating seafarers accordingly. As a result of Degree of Recognition and AHP analysis, it is analyzed that a new training system is required because the current training and education system may cover the job competencies of emergency response, caution and danger navigation, general sailing, cargo handling, seaworthiness maintenance, emergency response, and ship maintenance and management, but jobs such as remote control, monitoring diagnosis, device management capability, and big data analysis require competency for unmanned and shore based control.By evaluating the importance of change factors in the duties of seafarers in Maritime Autonomous Surface Ships, this study provides information on seafarers educational institutions response strategies for nurturing seafarers and prioritization of resource allocation, etc. The importance of factors was compared and evaluated to suggest changes in the duties of seafarers and methods of nurturing seafarers according to the introduction of Maritime Autonomous Surface Ships.It is expected that this study is meaningful as it systematically derived the duties and competency factors of seafarers of Maritime Autonomous Surface Ships from a practical point of view and analyzed the perception level of each relevant expert to diagnose expert-level responses to the introduction of Maritime Autonomous Surface Ships.