• Journal of Internet Computing and Services
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• v.18 no.6
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• pp.137-144
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• 2017

A variety of customized marketing strategies are being implemented in the telecommunications market, including the offering of gifts to consumers, as competition in the market is being restructured with the focus on bundled products. However, the Korea Communications Commission (KCC) has recently imposed fines for user discrimination on telecommunication carriers whose marketing strategies have included the award of excessive prizes. In that regard, various issues related to the suitability and appropriate limit of the current gift regulation in the telecommunications market have been raised. Since the Fair Trade Commission, which had a similar scheme to that of the KCC, abolished the regulation on gifts in July 2016, disputes have arisen as to whether the current regulation on gifts is practically effective from the perspective of consumer benefit. In other words, discussions on the rationality of the theoretical and empirical grounds for the regulation on gifts only in the telecommunication market but not in other commodities markets have begun. As such, this study aims to empirically analyze the suitability of the current regulation on gifts in the domestic telecommunications market under the new competitive environment centered on bundled products, and to seek the rational improvement of, and infer the implications for, the regulation on gifts in the telecommunications market based on the results of the analysis.

• Korean Journal of Social Welfare
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• v.66 no.1
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• pp.61-85
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• 2014

Lately, as the problem of the aged poverty becomes a big social issue, this paper studies the problem of financial stability with respect to the income and consumption of before-and-after retirement generations. After dividing the data in Korean Longitudinal Study of Ageing(KLoSA) into retired and non-retired groups, this study compares the difference among ageing groups by cross analysis and t-test. First, the result tells that the total personal income of retired group is lower than the one of non-retired group. Second, the public pension income benefit ratio of retired group is only 30% of it's total income, and the amount of public pension appears to be 40% of the total pension income. The benefit ratio of the personal pension income is low as about 1% in both groups, The private transfer income of the retired group takes relatively large portion in its total personal income. Third, as people gets older, financial stability gets worse because consumption does not decrease as much as the income decreases. Fourth, it is turned out that the expectation of old life supporting from nation is low in both groups. Fifth, the factors that affects the income of the public pension in the retired group are gender, age, education, and health status, when compared with the factors to the personal total income of the non-retired group. In terms of policy, this paper emphasizes the needs of the intensification of the public pension and the support for the revitalization of the personal pension.

• Journal of the Korea Society of Computer and Information
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• v.25 no.8
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• pp.159-172
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• 2020

Social networking services (SNS) are developing significantly with the Internet and smartphones. It's a friendly social media, but if you think deeply about it, you'll find that it has a variety of faces. It is a communication tool between users, a medium for delivering information, an infrastructure for providing applications, and a community where people with common interests gather. In recent years, business tools, shopping and payment methods are also being swallowed. The influence of the spread of SNS on the real world is also expanding, and the work being dealt with from a sociological perspective is also increasing. Also, if you pay attention to the technical aspects of SNS, it is composed of various technical elements, such as infrastructure that handles large-scale access, user interface that supports comfortable use, and big data analysis to understand people's behavior more deeply. However, I usually use it as usual. However, if you look through SNS, you can see that the situation is surprisingly profound and multifaceted. This study began by looking at the history and current status of SNS and attempted to find its status through comparison with other media. From the point of view of relationship with society, it can be a risk and legal issue when using SNS, such as crimes using bad social media or social media. It is also necessary to comment on the activities on SNS or the guidelines established by the operators. Therefore, various legal issues on SNS will be discussed. Also, as an example of using SNS, I will introduce an example of using SNS in disaster response. From a more technical point of view, you will receive commentary on SNS's network-based technology and SNS's information use, and these articles will help you understand and use SNS safely and help you further utilize or develop SNS.

• The Journal of the Korea Contents Association
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• v.19 no.12
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• pp.28-37
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• 2019

It is apparently clear that K-pop has been expanding its influence overseas, with its high growth rate. As a result, attempts have been made to analyze the characteristics of K-Pop in various academic fields. This research quantitatively used the participatory use process of K-Pop contents in voluntary participation and dissemination of the audience in the Trans-Media environment. The author examined the use of participatory K-Pop contents from the view point of reparability through big data content analysis. It has been revealed that K-Pop is spreading globally through social media, fans of various countries like to play K-Pop, and they make up their own content and form a participatory culture. In addition, we looked at when the moments of momentum in which participatory use is soaring were popular content and who was the publisher.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.765-773
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• 2017

With the end of the HFA (Hyogo Framework Action) in 2015, SFDRR (Sendai Framework for Disaster Risk Reduction) was adopted as a new agenda for disaster risk reduction at the 3th WCDRR (World Conference on Disaster Risk Reduction), held in March 2015. Continued understanding of the international agenda for reducing disaster risk is critical to disaster risk reduction at the national level as well as international level. Therefore, in this study, we analyzed major changes in the international agenda for disaster risk reduction as the transition from HFA to SFDRR, and analyzed South Korea's major achievements in the HFA and the implementation status of SFDRR in South Korea. In addition, SFDRR emphasizes the role of science and technology in policy making, and examined research trends in science and technology. 49.9% of the efforts were made to prevent the disasters during the disaster management stage, and plans related to priority 1 (40.4%) and 4 (35.8%) were mainly promoted. Science and technology research and development for disaster management were analyzed as active, but 79.7% of the tasks were related to priority 4, and it is necessary to develop all four priorities. Recently, disaster management using next-generation disaster prevention technologies such as satellite technology and big data is required, and it is expected that it will contribute effectively to mitigate disaster risk through establishment of education and policy to support it.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.319-326
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• 2020

PRNGs(Pseudorandom number generators) are essential for generating encryption keys for to secure online communication. A bitstream generated by the PRNG must be generated at high speed to encrypt the big data effectively in a symmetric key cryptosystem and should ensure the randomness of the level to pass through the several statistical tests. CA(Cellular Automata) based PRNGs are known to be easy to implement in hardware and to have better randomness than LFSR based PRNGs. In this paper, we design PRNGs based on PMLCA(Programable Maximum Length CA) that can generate effective key sequences in symmetric key cryptosystem. The proposed PRNGs generate bit streams through nonlinear control method. First, we design a PRNG based on an (m,n)-cell PMLCA ℙ with a single complement vector that produces linear sequences with the long period and analyze the period and the generating polynomial of ℙ. Next, we design an (m,n)-cell PC-MLCA based PRNG with two complement vectors that have the same period as ℙ and generate nonlinear sequences, and analyze the location of outputting the nonlinear sequence.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.507-519
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• 2013

This study is to evaluate agricultural water supply capacity in Geum river basin (9,865 $km^2$), one of the 5 big river basin of South Korea using MODSIM-DSS (MODified SIMyld-Decision Support System) model. The model is a generalized river basin decision support system and network flow model developed at Colorado State University designed specifically to meet the growing demands and pressures on river basin management. The model was established by dividing the basin into 14 subbasins and the irrigation facilities viz. agricultural reservoirs, pumping stations, diversions, culverts and groundwater wells were grouped and networked within each subbasin and networked between subbasins including municipal and industrial water supplies. To prepare the inflows to agricultural reservoirs and multipurpose dams, the Soil and Water Assessment Tool (SWAT) was calibrated using 6 years (2005-2010) observed dam inflow and storage data. By MODSIM run for 8 years from 2004 to 2011, the agricultural water shortage had occurred during the drought years of 2006, 2008, and 2009. The agricultural water shortage could be calculated as 282 $10^6m^3$, 286 $10^6m^3$, and 329 $10^6m^3$ respectively.

• The Journal of Bigdata
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• v.5 no.1
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• pp.155-180
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• 2020

It takes the most important role the problem of assigining vehicles and desigining optimal routes for each vehicle in order to enhance the logistics service level. While solving the problem, various cost factors such as number of vehicles, the capacity of vehicles, total travelling distance, should be considered at the same time. Although most of logistics service providers introduced the Transportation Management System (TMS), the system has the limitation which can not consider the practical constraints. In order to make the solution of TMS applicable, it is required experts revised the solution of TMS based on their own experience and intuition. In this research, different from previous research which have focused on minimizing the total cost, it has been proposed the methodology which can enhance the efficiency and fairness of asset utilization, simultaneously. First of all, it has been adopted the Cluster-First Route-Second (CFRS) approach. Based on the location of customers, we have grouped customers as clusters by using four different clustering algorithm such as K-Means, K-Medoids, DBSCAN, Model-based clustering and a procedural approach, Fisher & Jaikumar algorithm. After getting the result of clustering, it has been developed the optiamal vehicle routes within clusters. Based on the result of numerical experiments, it can be said that the propsed approach based on CFRS may guarantee the better performance in terms of total travelling time and distance. At the same time, the variance of travelling distance and number of visiting customers among vehicles, it can be concluded that the proposed approach can guarantee the better performance of assigning tasks in terms of fairness.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.6
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• pp.67-78
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• 2017

Traffic congestion cost is increasing annually. Specifically congestion caused by the CDB traffic contains more than a half of the total congestion cost. Recent advancement in the field of Big Data, AI paved the way to industry revolution 4.0. And, these new technologies creates tremendous changes in the traffic information dissemination. Eventually, accurate and timely traffic information will give a positive impact on decreasing traffic congestion cost. This study, therefore, focused on developing both recurrent and non-recurrent congestion prediction models on urban roads by adopting Recurrent Neural Network(RNN), a tribe in machine learning. Two hidden layers with scaled conjugate gradient backpropagation algorithm were selected, and tested. Result of the analysis driven the authors to 25 meaningful links out of 33 total links that have appropriate mean square errors. Authors concluded that RNN model is a feasible model to predict congestion.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.5
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• pp.343-349
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• 2013

Crashworthy fuel cells have a great influence on improving the survivability of crews. Since 1960's, the US army has developed a detailed military specification, MIL-DTL-27422, defining the performance requirements for rotorcraft fuel cells. In the qualification tests required by MIL-DTL-27422, the crash impact test should be conducted to verify the crashworthiness of fuel cell. Success of the crash impact test means the improvement of survivability of crews by preventing post-crash fire. But, there is a big risk of failure due to huge external load in the crash impact test. Because the crash impact test itself takes a long-term preparation efforts together with costly fuel cell specimens, the failure of crash impact test can result in serious delay of a entire rotorcraft development. Thus, the numerical simulations of the crash impact test has been required at the early design stage to minimize the possibility of trial-and-error with full-scale fuel cells. Present study performs the numerical simulation using SPH(smoothed particle hydro-dynamic) method supported by a crash simulation software, LS-DYNA. Test condition of MIL-DTL-27422 is reflected on analysis and material data is acquired by specimen test of fuel cell material. As a result, the resulting equivalent stresses of fuel cell itself are calculated and vulnerable areas are also evaluated.