• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.3
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• pp.93-104
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• 2010

The advent of various mobile devices and mobile services has caused diversification of information stored in a mobile device, e.g., SMS, photos, movies, addresses, e-mails, digital certificates, and so on. Because mobile devices are lost or stolen easily, user authentication is critical to protect the information stored in mobile devices. However, the current user authentication methods using Personal Identification Numbers (PINs) and passwords are vulnerable to Shoulder Surfing Attacks (SSAs), which enables an attacker to obtain user's information. Although there are already several SSA-resistant authentication methods in the literature, most of these methods lack of usability. Moreover, they are not suitable for use in mobile devices. In this paper, we propose a user friendly password input method for mobile devices which is secure against SSA. We also perform user tests and compare the security and usability of the proposed method with those of the existing password input methods.

• Journal of the Korea Society of Computer and Information
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• v.27 no.10
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• pp.115-121
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• 2022

In this paper, we analyze trends in the use of mobile forensic technology, focusing on cases where mobile forensics are used, and we predict the development of future mobile forensics technology using linear regression used in future prediction models. For the current status and outlook analysis, we extracted a total of 8 variables by analyzing 1,397 domestic and foreign mobile forensics-related cases and newspaper articles. We analyzed the prospects for each variable using the year of occurrence as an independent variable, seven variables such as text (text message usage information), communication information (cell phone communication information), Internet usage information, messenger usage information, stored files, GPS, and others as dependent variables. As a result of the analysis, among various aspects of the use of mobile devices, the use of Internet usage information, messenger usage information, and data stored in mobile devices is expected to increase. Therefore, it is expected that continuous research on technologies that can effectively extract and analyze characteristic information of mobile devices such as file systems, the Internet, and messengers will be needed As mobile devices increase performance and utilization in the future and security technology.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.165-172
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• 2024

In this paper, we designed a smart home system that can be used intuitively and easily in everyday life, such as sending text messages to users, providing various information and scheduling using smart AI, and providing lighting and atmosphere suitable for the atmosphere in situations such as listening to music using neopixels, as well as using ESP32, RFID, and Google Cloude Console using raspberry pie. As a result of the experiment, it was confirmed that security characters were normally sent to users when RFID was recognized on ESP32 connected to Wi-Fi even if the power was reconnected, and smart AI using Neopixel lighting, Raspberry Pie, and voice recognition, which calculated frequency, also changed the recognition rate over distance, but it worked.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.4
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• pp.387-393
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• 2013

In shipyard site, a ship is constructed by integrating lots of modules that are made in several sites with different capabilities and specifications. Recently, it needs to make a shipyard to be smart with wired and wireless broadband networks between hierarchical shipyards. In this paper, we propose an installation of LTE femtocell local gateway at a remote shipyard, an information exchange method between hierarchical shipyards, and an offload method to separate the general traffic. We define the mode change in a femtocell gateway for supporting the offload of the general traffic between the headquarter and a remote shipyard, the offload data management and trigger message, and cache entry fields. To show the operation of our proposed off-loading function, we consider the transcipient message flow at the femtocell gateway with its state transition diagram. Hence, it is expected to increase the productivity of shipyard industry with mobile communications and broadband Internet technologies.

• Journal of IKEEE
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• v.23 no.4
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• pp.1393-1399
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• 2019

With the rapid growth of the Internet, millions of indiscriminate advertising SMS are sent every day because of the convenience of sending and receiving data. Although we still use methods to block spam words manually, we have been actively researching how to filter spam in a various ways as machine learning emerged. However, spam words and patterns are constantly changing to avoid being filtered, so existing machine learning mechanisms cannot detect or adapt to new words and patterns. Recently, the concept of Lifelong Learning emerged to overcome these limitations, using existing knowledge to keep learning new knowledge continuously. In this paper, we propose a method of spam filtering system using ensemble techniques of naive bayesian which is most commonly used in document classification and LLML(Lifelong Machine Learning). We validate the performance of lifelong learning by applying the model ELLA and the Naive Bayes most commonly used in existing spam filters.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.39 no.4
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• pp.10-18
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• 2002

Network topology design is a multiobjective problem with various design components. The components such as cost, message delay and reliability are important to gain the best performance. Recently, Genetic Algorithms(GAs) have been widely used as an optimization method for real-world problems such as combinatorial optimization, network topology design, and so on. This paper proposed a method of Multi-objective GA for Design of the network topology which is to minimize connection cost and message delay time. A common difficulty in multiobjective optimization is the existence of an objective conflict. We used the prufer number and cluster string for encoding, parato elimination method and niche-formation method for the fitness sharing method, and reformation elitism for the prevention of pre-convergence. From the simulation, the proposed method shows that the better candidates of network architecture can be found.

• The Journal of Korean society of community based occupational therapy
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• v.10 no.3
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• pp.1-13
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• 2020

Objective : The purpose of this study is to present an analysis model in developing an inclusive response for safety hazards and disaster preventive information system for vulnerable people to the disaster including persons with disabilities, and those with specific needs. Methods : In this study, the persona analysis method is used to analyze fictitious characters that correspond to various characteristics such as age, disability, environment, occupation, etc. in terms of the scenario of some particular disaster subjects. Based on the user's communication problems derived from the persona analysis, focused group interview and ICF based analysis were implemented to identify needs and arbitration methods. Results : The needs from persona analysis and ICF-based communication items analysis identifies the factors that make each fictitious character difficult in terms of communication in obtaining the benefits consistent with the purpose of the service. The study derives service requirements that can provide arbitration or facilitation methods to increase communication ability of the users. Conclusion : Through the persona analysis method, difficulties that could occur when receiving disaster information using communication devices were identified and analyzed in conjunction with communication problems described in the ICF. In building information services for the prevention of safety hazards and disasters, this study presented a model that uses the persona analysis method and the ICF classification system to derive user requirements for accessible information system.

• The Journal of the Korea Contents Association
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• v.14 no.6
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• pp.200-210
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• 2014

Purpose: The purpose of this study was done to investigate the relationship between self esteem, impulsive behavior and mental health among adolescents who were cellular phone addiction and those who were not. Methods: The data were collected using questionnaire from the sample of 239 middle school students. The data were collected from April 8 to 19, 2013. Data were analyzed using frequencies, means, ${\chi}^2$-test, Fisher's exact test, t-test and logistic regression analysis with SPSS 20.0. Results: Firstly, Significant differences were found for grade, sex, period, buying motives, the number of the messages/day, use, phone bill, callers between students who were cellular phone addiction and those who were not. Secondly, Self esteem for the cellular phone addiction were lower than for those in the non-addiction group, and impulsive behavior and mental health were higher. Thirdly, The logistic regression analysis revealed that self esteem, non-planning impulsiveness, mental health total, grade, sex, period, and the number of the messages/day significantly associated with being a cellular phone addiction. Conclusions: The result of this study offer basic data for the development of intervention programs to prevent adolescents cellular phone addiction.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.63-69
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• 2010

Today, Internet Telephony Services based on VoIP are gaining tremendous popularity for general user. Therefore a various demands of the user keep up increase, the most important requirements of these is voice security about telephony system. It is needed to ensure secret of voice call in a special situation. Due to the fact that many users can connect to the internet at the same time, VoIP can always be in a defenseless state by hackers. Therefore, in this paper, we have developed VPN IP-PBX for the voice security and measured conversation quality by adopting VPN IPsec based on SIP and using tunnel method in transmitting voice data to prevent eavesdrop of voice data. This VPN IP-PBX that is connected Soft-phone provide various optional services.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.1-6
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• 2014

This paper proposes a mobile content curation service to collect various online/offline publications. The company publishes one-time topic information to a broker server in advance and customer curates topic information on a mobile device by requesting it. The main characteristics of the proposed service are: it is based on request/response model rather than existing publish/subscribe model, can easily specify topic information by input string without QR code or audio recognition, and retrieves all of topic information anywhere anytime by storing it on mobile device. This service can be used for second screen campaign for TV and various online/offline events.