• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.2
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• pp.334-348
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• 2015

Widespread use of smart devices accompanies increase of use of access point (AP), which enables the connection to the wireless network. If the appropriate security is not served when a user tries to connect the wireless network through an AP, various security problems can arise due to the rogue APs. In this paper, we are going to examine the threat by evil-twin, which is a kind of rogue APs. Most of recent researches for detecting rogue APs utilize the measured time difference, such as round trip time (RTT), between the evil-twin and authorized APs. These methods, however, suffer from the low detection rate in the network congestion. Due to these reasons, in this paper, we suggest a new factor, packet inter-arrival time (PIAT), in order to detect evil-twins. By using both RTT and PIAT as the learning factors for the support vector machine (SVM), we determine the non-linear metric to classify evil-twins and authorized APs. As a result, we can detect evil-twins with the probability of up to 96.5% and at least 89.75% even when the network is congested.

• Journal of Nutrition and Health
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• v.48 no.6
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• pp.519-529
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• 2015

Purpose: The purpose of this study was to examine the prevalence of food insecurity in Korean elderly and to analyze the health status as well as food and nutrient intakes according to food insecurity status. Methods: A total of 939 elderly subjects (over 65 years old) were used in our analysis from the fifth 2010 Korean National Health and Nutrition Examination Survey (KNHANES V-1). The variables consisted of general characteristics, physical and mental health, nutrient intake, rate of deficient intake of energy and nutrients compared with Dietary Reference Intakes for Koreans (KDRIs) and food quality and diversity according to the status of food insecurity. Food insecurity status was measured using a self-reported food security questionnaire on the dietary situation in the previous year, and participants were classified according to three groups: food secure group, mildly food insecure group, and moderately/severely food insecure group. Results: The proportion of the food insecure group was approximately 67% and the food insecure group had lower income and educational status than the food secure group. Food insecurity was associated with worse physical and mental health status after adjusting potentially confounding variables. The results showed that food insecurity in Korean elderly significantly affected mental health (including stress cognition, depression experience, and suicide thoughts) which exceeded stages of physical health. In addition, food insecurity showed significant association with low nutrient intake and high rate of deficient intakes of energy and nutrients compared with KDRIs, and a reduction of dietary quality and diversity was indicated in the food insecure group. Conclusion: This study concludes that the prevalence of food insecurity may affect the physical and mental health as well as dietary intake of the elderly Korean population. Therefore, food insecurity should be considered as an important public health issue in Korea.

• Journal of the Korea Society of Computer and Information
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• v.28 no.8
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• pp.103-109
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• 2023

In this paper, we propose a smart wall switch based on IEEE 802.11b/g/n standard 2.4GHz band communication. As the 4th industrial era evolves, smart home solution development is actively underway, and application cases for smart wall switches are increasing. Most of the Chinese products that preoccupy the market through price competitiveness use Bluetooth and Zigbee communication switches. However, while ZigBee communication is low power, communication speed is slower than Bluetooth and network configuration through a separate hub is additionally required. The Bluetooth method has problems in that the communication range and speed are lower than Wi-Fi communication, the communication standby time is relatively long, and security is weak. In this study, an IEEE 802.11b/g/n smart wall switch applied with Wi-Fi communication technology was developed. In addition, through the two-wire structure, it is designed so that no additional cost is incurred through the construction of a separate neutral line in the building. The result of the study is more than 30% cheaper than the existing wall switch, so it is judged that it will be able to preoccupy the market not only in terms of technological competitiveness but also price competitiveness.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.8-14
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• 2020

Recently, there was an increasing demand for an integrated access control system which is capable of user recognition, door control, and facility operations control for smart buildings automation. The market available door lock access control solutions need to be improved from the current level security of door locks operations where security is compromised when a password or digital keys are exposed to the strangers. At present, the access control system solution providers focusing on developing an automatic access control system using (RF) based technologies like bluetooth, WiFi, etc. All the existing automatic door access control technologies required an additional hardware interface and always vulnerable security threads. This paper proposes the user identification and authentication solution for automatic door lock control operations using camera based visible light communication (VLC) technology. This proposed approach use the cameras installed in building facility, user smart devices and IoT open source controller based LED light sensors installed in buildings infrastructure. The building facility installed IoT LED light sensors transmit the authorized user and facility information color grid code and the smart device camera decode the user informations and verify with stored user information then indicate the authentication status to the user and send authentication acknowledgement to facility door lock integrated camera to control the door lock operations. The camera based VLC receiver uses the artificial intelligence (AI) methods to decode VLC data to improve the VLC performance. This paper implements the testbed model using IoT open-source based LED light sensor with CCTV camera and user smartphone devices. The experiment results are verified with custom made convolutional neural network (CNN) based AI techniques for VLC deciding method on smart devices and PC based CCTV monitoring solutions. The archived experiment results confirm that proposed door access control solution is effective and robust for automatic door access control.

• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.473-480
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• 2019

The smart home is a technology that can monitor and control by connecting everything to a communication network in various fields such as home appliances, energy consumers, and security devices. The Smart home is developing not only automatic control but also learning situation and user's taste and providing the result accordingly. This paper proposes a model that can provide a comfortable indoor environment control service for the user's characteristics by detecting the user's behavior as well as the automatic remote control service. The whole system consists of ESP 8266 with sensor and Wi-Fi, Firebase as a real-time database, and a smartphone application. This model is divided into functions such as learning mode when the home appliance is operated, learning control through learning results, and automatic ventilation using indoor and outdoor sensor values. The study used moving averages for temperature and humidity in the control of home appliances such as air conditioners, humidifiers and air purifiers. This system can provide higher quality service by analyzing and predicting user's characteristics through various machine learning and deep learning.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.249-256
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• 2020

It is expected that the technology of the fourth industrial revolution will increase the productivity and efficiency of the industrial world. Many countries are providing political and financial supports to make big advances in the technology. Especially, developed countries, such as USA, Germany and Japan, are trying to use the technology for manufacturing and finance industry, and to increase the opportunity of test-bed environment. However, many restrictions hinder adopting non-governmental technology in defense due to various limitations such as national security and protection of technology. In this study, we propose methods to adopt new and non-governmental technology in defense through by investigating internal and external policies related to technology and case studies. First, it is necessary to expand opportunities to let small and medium sized companies participate in defense R&D projects. Second, it is important to improve R&D systems for introducing new and non-governmental technology on the defense industry. Third, it is needed to increase test-bed environments for experimenting and evaluating new technologies in the defense industry. Thus, we expect that the proposed methods will help form strategies for small and medium sized companies, and analyze trends for introducing new technologies in the defense industry.