• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.712-719
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• 2013

This paper studies the security module for the reliable transmission of the meter reading and the control data between the remote terminals and the upper server-side in smart water grid. The proposed security module was implemented to make it attachable to the remote terminal without security function. In particular, unlike the smart grid of electric field, the low power is considered due to the use of battery power in the smart water grid, and the ARIA-GCM-128 symmetric key method is adopted taking into the account that the damp and constrictive environments by the installed meter location in the underground occur a communication obstacle on building of the large-scale network system. The encryption module of this paper was devised to ensure the safety between the reading data on the terminal and the control data from the upper server, and secure the stability of the remote meter reading system by taking protection against an arbitrary alteration or modification.

• Journal of Digital Convergence
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• v.17 no.11
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• pp.195-200
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• 2019

The role of the Internet of Things in the Fourth Industrial Revolution is in the era of collecting data at the end and analyzing big data through technology to analyze the future or behavior. Therefore, due to the nature of the IoT, it is vulnerable to security and requires a lightweight security protocol. The spread of things Internet technology is changing our lives a lot. IT companies all over the world are already focusing on products and services based on things Internet, and they are going to the era of all things internet that can communicate not only with electronic devices but also with common objects. People, people, people and objects, things and things interact without limitation of time and space, collecting, analyzing and applying information. Life becomes more and more smart, but on the other hand, the possibility of leakage of personal information becomes greater. Therefore, this study proposed security threats that threaten the protection of personal information and countermeasures, and suggested countermeasures for building a secure IoT environment suitable for the Fourth Industrial Revolution.

• Journal of the Korean Society of Safety
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• v.34 no.5
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• pp.15-21
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• 2019

A rack-type warehouse has the advantage of storing a large amount in a small area by loading goods vertically. But in terms of fire risk, the fire load is very high, which can cause massive damage in the event of a fire. In the United States, research has been actively conducted to minimize the spread of vertical fires, and relevant standards have been established and operated. In Korea, research and related standards are insufficient to prevent the vertical spread of rack-type warehouse fires. In this study, an experimental study was conducted to prevent the vertical spread of a rack-type warehouse fire using a horizontal barrier and in-rack sprinklers. As a result of the test, the horizontal barrier considering the continuous flame prevented the vertical spread of the flame for a certain time. However, the horizontal barrier with continuous flame did not show the effect of preventing continuous flame. The combination of the horizontal barrier and the in-rack sprinkler prevented the vertical spread of fire effectively. In addition, the heat collecting effect through the horizontal barrier was shown and helped the early operation of the in-rack sprinklers.

• Journal of Convergence for Information Technology
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• v.8 no.6
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• pp.173-186
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• 2018

While cloud services are expanding, many users are having difficulty in adopting cloud services. This is because there is no information as to which cloud services can be trusted by users. loud service level agreement (Cloud SLA) is an agreement between cloud service providers and cloud service consumers using qualitative and quantitative indicators including quality and performance, etc. of cloud services. In this study, we propose a framework for cloud SLA that can be applied to the domestic cloud industry to improve service levels for cloud service providers and to protect users and also derive the detailed components of cloud SLA applicable to the domestic cloud industry using the proposed framework. Through this result, it is expected that the government will utilize the policy to enhance the reliability between cloud service providers and users under "the Act on the Development of Cloud Computing and Protection of Users", and eventually to activate cloud services by improving the quality and performance level of domestic cloud services and building a user trust.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.2
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• pp.138-144
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• 2019

To analyze the present state of buildings suspended in Gangwon and estimate the compressive strength by visual inspection and Schmidt hammer method in order to analyze durability etc.. In this study, we analyzed the problems that existed in the location where construction is suspended and efficient management method. Expected construction restoration of construction will be restarted, and important parts of the construction site should be given the best protection measures so that the quality can be maintained thoroughly. The construction of the suspended construction is exposed to the freezing and thawing damage over time. Therefore, it is necessary to take measures such as maintenance, and take protective measures by establishing a plan to improve the durability of buildings that are under construction.

• Journal of Intelligence and Information Systems
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• v.24 no.4
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• pp.85-110
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• 2018

A chatbot is an interactive assistant that utilizes many communication modes: voice, images, video, or text. It is an artificial intelligence-based application that responds to users' needs or solves problems during user-friendly conversation. However, the current version of the chatbot is focused on understanding and performing tasks requested by the user; its ability to generate personalized conversation suitable for relationship-building is limited. Recognizing the need to build a relationship and making suitable conversation is more important for social chatbots who require social skills similar to those of problem-solving chatbots like the intelligent personal assistant. The purpose of this study is to propose a text analysis method that evaluates relationships between chatbots and users based on content input by the user and adapted to the communication situation, enabling the chatbot to conduct suitable conversations. To evaluate the performance of this method, we examined learning and verified the results using actual SNS conversation records. The results of the analysis will aid in implementation of the social chatbot, as this method yields excellent results even when the private profile information of the user is excluded for privacy reasons.

• International Journal of High-Rise Buildings
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• v.7 no.4
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• pp.375-387
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• 2018

This paper presents a review on progressive collapse mechanism of steel framed buildings exposed to fire. The influence of load ratios, strength of structural members (beam, column, slab, connection), fire scenarios, bracing systems, fire protections on the collapse mode and collapse time of structures is comprehensively reviewed. It is found that the key influencing factors include load ratio, fire scenario, bracing layout and fire protection. The application of strong beams, high load ratios, multi-compartment fires will lead to global downward collapse which is undesirable. The catenary action in beams and tensile membrane action in slabs contribute to the enhancement of structural collapse resistance, leading to a ductile collapse mechanism. It is recommended to increase the reinforcement ratio in the sagging and hogging region of slabs to not only enhance the tensile membrane action in the slab, but to prevent the failure of beam-to-column connections. It is also found that a frame may collapse in the cooling phase of compartment fires or under travelling fires. This is because that the steel members may experience maximum temperatures and maximum displacements under these two fire scenarios. An edge bay fire is more prone to induce the collapse of structures than a central bay fire. The progressive collapse of buildings can be effectively prevented by using bracing systems and fire protections. A combination of horizontal and vertical bracing systems as well as increasing the strength and stiffness of bracing members is recommended to enhance the collapse resistance. A protected frame dose not collapse immediately after the local failure but experiences a relatively long withstanding period of at least 60 mins. It is suggested to use three-dimensional models for accurate predictions of whether, when and how a structure collapses under various fire scenarios.

• The Journal of Bigdata
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• v.3 no.2
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• pp.1-10
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• 2018

In the field of smart water management, there is an increasing demand for strengthening competitiveness through big data analysis. As a result, systematic management (Governance) of big data is becoming an important issue. Big data governance is a systematic approach to evaluating, directing and monitoring data management, such as data quality assurance, privacy protection, data lifetime management, data ownership and clarification of management rights. Failure to establish big data governance can lead to serious problems by using low quality data for critical decisions. In addition, personal privacy data can make Big Brother worry come true, and IT costs can skyrocket due to the neglect of data age management. Even if these technical problems are fixed, the big data effects will not be sustained unless there are organizations and personnel who are dedicated and responsible for data-related issues. In this paper, we propose a method of building data governance for smart water data management based on big data.

• Ecology and Resilient Infrastructure
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• v.7 no.4
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• pp.336-344
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• 2020

The prediction and evaluation of driftwood accumulation around river-crossing structures are essential because driftwood accumulation increases during flood disasters. In this study, the driftwood accumulation and behavior around bridge piers were evaluated via a numerical model that could be employed to analyze three-dimensional turbulent flow and driftwood motion. The moving particle semi-implicit-based model for driftwood motion was sensitive to the number of spheres. The numerical results showed that the approach velocity and the ratio of driftwood length to pier width were the key factors influencing driftwood accumulation, whereas the driftwood density had only a minor influence. Overall, it is expected that this study will contribute to the development of improved risk evaluation indexes for assessing driftwood accumulation around river-crossing structures.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.2
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• pp.23-31
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• 2018

In recent years, as the development of construction technology and population increase, buildings are becoming more complex and high-rise. These large scale buildings are difficult to secure fire and evacuation safety when fire occurs. So it is necessary to prepare specific measures. According to this situation, in 2011, Republic of Korea officially launched Performance-based Design in "Fire-fighting system Installation business Act". But even 6 years passed since the enforcement, there are still faces manifold problems in the course of implementation. In order to examine the necessary improvements, in this study, I conducted interviews and questionnaires with experts, investigated the improvement items under current laws. And draw up a measures for that items. The subjects of the survey were fire-fighting officer, professional engineer fire fighting, fire protection planner and professor in Daegu. As a result of twice surveys, a total of 19 items are derived. And then compared and analyzed the criteria of overseas countries, and suggested improvement directions for final items. In addition, conducted a third questionnaire survey on the proposed improvement direction to verify the appropriateness of the alternative. The results of this study will be used as basic data to deal with the general problems of performance-based design in future, and further study on each item will be needed.