• KIPS Transactions on Computer and Communication Systems
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• v.11 no.10
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• pp.373-380
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• 2022

This paper presents a deep learning based group synchronization that supports networked immersive interactions between remote users. The goal of group synchronization is to enable all participants to synchronously interact with others for increasing user presence Most previous methods focus on NTP-based clock synchronization to enhance time accuracy. Moving average filters are used to control media playout time on the synchronization server. As an example, the exponentially weighted moving average(EWMA) would be able to track and estimate accurate playout time if the changes in input data are not significant. However it needs more time to be stable for any given change over time due to codec and system loads or fluctuations in network status. To tackle this problem, this work proposes the Deep Group Synchronization(DeepGroupSync), a group synchronization based on deep learning that models important features from the data. This model consists of two Gated Recurrent Unit(GRU) layers and one fully-connected layer, which predicts an optimal playout time by utilizing the sequential playout delays. The experiments are conducted with an existing method that uses the EWMA and the proposed method that uses the DeepGroupSync. The results show that the proposed method are more robust against unpredictable or rapid network condition changes than the existing method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3B
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• pp.285-293
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• 2010

Soil moisture is a key factor to control the exchange of water and energy between the surface and the atmosphere. In recent, many researches for spatial and temporal variability analyses of soil moisture have been conducted. In this study, we analyzed the spatio-temporal variability of soil moisture in Walnut Gulch Experimental Watershed, Arizona, U.S. during the Soil Moisture Experiment 2004 (SMEX04). The spatio-temporal variability analyses were performed to understand sensitivity of five observation sites with precipitation and relationship between mean soil moisture, and its standard deviation and coefficient of variation at the sites, respectively. It was identified that log-normal distribution was superior to replicate soil moisture spatial patterns. In addition, precipitation was identified as a key physical factor to understand spatio-temporal variability of soil moisure based on the temporal stability analysis. Based on current results, higher spatial variability was also observed which was agreed with the results of previous studies. The results from this study should be essential for improvement of the remotely sensed soil moisture retrieval algorithm.

• Journal of Korea Technology Innovation Society
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• v.16 no.4
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• pp.954-977
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• 2013

This paper investigates the factors to affect the consumer selection of machine-to-machine (M2M) technology in the purchase and utilization of home appliances. M2M technology, based on mobile internet, allows for automatic operation and remote control of home appliances and equipment. The introduction of M2M technology could lead to the saving of domestic housework and of active social participation for women. With a view to focusing on the liberating potential of M2M technology, this paper analyzes the correlation between four independent variables (gender, income, employment status of married woman, and possession of mobile internet devices) and two dependent variables (intention for purchase and utilization of M2M household appliances). The possession of mobile internet devices such as smart phone and tablet PC turns out to be the most significant factor to affect both the purchase and utilization of M2M household appliances. The employment status (employed or not-employed) affects only the intention for purchase. Neither the income level nor gender has significant correlation with the intention for purchase or utilization. The results differ from the conventional wisdom that the consumer selection of household technology is substantially affected by gender, income and employment of housewife.

• Progress in Medical Physics
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• v.8 no.1
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• pp.25-29
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• 1997

Ir-192 source activity for high dose rate brachytherapy is measured using Farmertype ionization chamber. The source-to-chamber distance is 10 cm and the measured charge unit is converted to activity unit. The measured values are compared to the values provided from vendor. Because of time dependency of Ir-192 source activity, the activities are regularly checked and compared to calculated values. As the accuracy of Ir-192 source activity is depend on the mechanical measurement setup, we estimated the precision of remote controlled source dwell position using home-made device and film scanner. The difference between measured and predicted dwell position is within 1 mm. As a result, the errors of source activity are 0.7${\pm}$1.5 ％ for measured and vendor-provided values and 0.l${\pm}$1.2％ for measured and time-dependent calculated vlaues. In conclusion, our measured activity has been comparable to the values provided from vendor and our brachytherapy unit has been very accurate until now. Regular quality control of brachytherapy is essential for successful treatment which depends on the accuracy of source position and activity.

• Journal of Society of Preventive Korean Medicine
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• v.4 no.1
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• pp.1-16
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• 2000

From 1998, Oriental Medical Physicians(OMP) is distributed in Public Health Sector. but long term plan for Oriental Medicine in Public Health is not existed. So, this study is designed for the activation of OMP Subjects in this study were comprised 3 groups of oriental medicine related persons, the group of which are Students of 11 Oriental Medical Schools, Oriental Medical Physicians in Public Health Sector, Specialist Croup of Oriental medicine Policy(total 1,458 persons). Data were collected from July 1st to November 30, 1999. Direct interview with key persons, systematic interview by using of interview protocol, e-mail and facsimile have been conducted. The results of survey were coded by Excel 5.0, and analysed with SAS 6.12 statistical package. Inter-group difference determined by T-test, and descriptive statistics have been examined. Major findings can be epitomized as follows. 1) OMP disposition to multifarious organizations and institutes such as Public Health Centers, Public Health Sub-centers, Public Hospitals, Private Hospitals in Remote-Vulnerable Area, Community Social Welfare Centers, Institutes for Heath Policy Research, etc, will promise an effective use of Oriental Medical Physician. 2) Average number of patients treated by OMP was 22.8, average budget for oriental medical department, in which OMP were affiliated, was 39.6 million Won per year. Direct cost per every patient visit was 7,210.9 Won, which is considered expensive for public health service. Therefore, development and transformation for Oriental Medical Service in Public Health Sector is desirable in economic and political aspects. 3) It is recommended that ${\ulcorner}Advisory\;Committee{\lrcorner},{\ulcorner}Planning\;Commission\;for\; Public\;Health\;in\;Oriental\;Medicine{\lrcorner}$ should be established for the activation and for the support of Oriental Medical Physician in Public Health Sector, 4) Most effective programmes for oriental public health doctor are health service programmes for the elderly, Home health visit, chronic degenerative disease control services(p<0.001). 5) Standard guideline for facilities and equipments of Oriental Medicine Department in Public Health Center is needed for optimal supply of resources and activation of public health activity.

• Journal of Korean Society of Transportation
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• v.26 no.6
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• pp.39-47
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• 2008

With dramatic development of IT technology and start of DMB service, installing the DMB equipment in a vehicle for watching TV programs and literal or pictorial traffic information are increasing. Watching the DMB during driving the vehicle could cause visual and cognitive distraction to drivers as much as eating food, operating radio and using mobile phone. However, there is not much empirical research for this topic and no research examined the effect of watching the DMB on driving behaviors in Korea. So, the present study examined the effect of watching the DMB on the driving behaviors with car simulator experiment. Within subject design was used in the study. That is, all subjects drove the vehicle both in the watching DMB condition and the non-watching DMB condition. The results indicated that subjects in the watching DMB condition took longer time to arrive at the destination and operated accelerator and brake pedal rapidly than subjects in the non-watching DMB condition. That is, their overall driving stability was lower than non-watching subjects'. Additionally, we examined the difference among the DMB control conditions (i.e., keypad condition, touch-pad condition and remote controller condition) in the driving behaviors. Finally, we discussed the limitations and the implications of the present study.

• Management & Information Systems Review
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• v.34 no.3
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• pp.79-100
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• 2015

This study is to examine the factors that influence purchasing behavior and decision-making when consumers buy goods through mobile shopping, define purchasing decision-making with the steps of problem recognition, information search, alternative assessment, and purchasing behavior to understand mobile consumer behavior, and investigate how the factors of each step play roles and influence consumers' purchasing decision-making through positive analysis to figure out consumer purchasing behavior in mobile shopping. The study results, First, the user characteristics of information search influence flow. Second, in the relations between the user characteristics in the step of information search and perceived risk in alternative assessment, if recognition on gains is higher, perceived risk for time loss gets lower, and when the level of skills is higher, perceived risk gets higher, and it has been partly adopted that innovativeness does not influence risk perception. Third, in the relations between flow experience and purchasing intention, it has been found to be partially significant that remote presence and challenge do not influence purchasing intention but do influence excitement, attention concentration, and control and also do influence perceived risk and purchasing intention. Fourth, according to the results of analyzing the difference of consumer purchasing behavior by the types of involvement, practical involvement and sensual involvement, user characteristics and flow, and perceived risk differ by the types of products in terms of the search process, thereby changing purchasing intention. Lastly, the significance and limitations of this study was discussed.

• Journal of Korea Water Resources Association
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• v.54 no.9
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• pp.681-692
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• 2021

Vegetation processes have a significant impact on rainfall runoff processes through evapotranspiration control, but are rarely considered in the conceptual lumped hydrological model. This study evaluated the model performance of the Hapcheon Dam watershed by integrating the ecological module expressing the leaf area index data sensed remotely from the satellite into the hydrological partition module. The proposed eco-hydrological model has three main features to better represent the eco-hydrological process in humid regions. 1) The growth rate of vegetation is constrained by water shortage stress in the watershed. 2) The maximum growth of vegetation is limited by the energy of the watershed climate. 3) The interaction of vegetation and aquifers is reflected. The proposed model simultaneously simulates hydrologic components and vegetation dynamics of watershed scale. The following findings were found from the validation results using the model parameters estimated by the SCEM algorithm. 1) Estimating the parameters of the eco-hydrological model using the leaf area index and streamflow data can predict the streamflow with similar accuracy and robustness to the hydrological model without the ecological module. 2) Using the remotely sensed leaf area index without filtering as input data is not helpful in estimating streamflow. 3) The integrated eco-hydrological model can provide an excellent estimate of the seasonal variability of the leaf area index.

• Journal of the Institute of Convergence Signal Processing
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• v.25 no.2
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• pp.94-99
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• 2024

Recently, wind power has been gaining attention as a highly efficient renewable energy source, leading to various technological developments worldwide. Typically, wind power is operated in the form of large wind farms with many wind turbines installed in areas rich in wind resources. However, in developing countries or regions isolated from the power grid, off-grid small wind power systems are emerging as an efficient solution. To efficiently operate and expand off-grid small-scale power systems, the development of real-time monitoring systems is required. For the efficient operation of small wind power systems, it is essential to develop real-time monitoring systems that can actively respond to excessive wind speeds and various environmental factors, as well as ensure the stable supply of produced power to small areas or facilities through an Energy Storage System (ESS). The implemented system monitors turbine RPM, power generation, brake operation, and more to create an optimal operating environment. The developed small wind power system can be utilized in remote road lighting, marine leisure facilities, mobile communication base stations, and other applications, contributing to the development of the RE100 industry ecosystem.

• Journal of Navigation and Port Research
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• v.46 no.1
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• pp.1-10
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• 2022

This study aims to investigate changes in the demand for ship officers 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 the skill of ship officer. It also analyzes and proposes a plan for nurturing ship officers accordingly. As a result of the degree of recognition and AHP analysis, this study suggests 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 tasks 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 ship officers in Maritime Autonomous Surface Ships, this study provides information on ship officer educational institutions' response strategies for nurturing ship officers and prioritization of resource allocation, etc. The importance of these factors was compared and evaluated to suggest changes in the duties of ship officers and methods of nurturing ship officers according to the introduction of Maritime Autonomous Surface Ships. It is expected that the findings of this study will be meaningful as it systematically derives the duties and competency factors of ship officers 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.