• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.4
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• pp.207-212
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• 2015

Wi-Fi Direct allows battery powered mobile devices to form a wireless ad hoc network. Since one member of the network called Group Owner (GO) takes the role of managing the network, the network lifetime is mainly affected by the energy efficiency of GO. Hence, Wi-Fi Direct defines power saving schemes that allow GO to save the energy by turning off its radio interface during the periods called absence periods. However, the Wi-Fi Direct specification does not specify how to set parameters (denoted by PS parameters) determining the schedule of the absence periods. In this paper, we therefore propose a novel traffic-aware power saving scheme for Wi-Fi Direct networks. In particular, the proposed scheme estimates the application-level traffic load and adaptively tunes the PS parameters according to the estimated value.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.186-188
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• 2014

In recent years, domestic as well as LTE wireless network of Wi-Fi and most used. In addition, mobile-intensive services that used mainly in our society makes it easier, SNS, application (APP), and file downloads. As such, the amount of data requested, while living at the time of mobile users will want to be safe from the earliest. And the wireless network communications mortality (3G, 4G (LTE), LTE-A) and Wi-Fi (802.11 n-2.4 G H z z H a c-5, 802.11 G), and users are mainly used in the death 4G (LTE), communication Wi-Fi, 802.11 n-2.4 GHz are used most frequently. As above, use the wireless network in order to safely and quickly developed the technology of the Li-Fi. Li-Fi light (visible light) technology to communicate with, and Wi-Fi (802.11 n-2.4 G z H) 100 times faster, LTE-A 66 times faster. However, the current Li-Fi to commercialise the big issue exists. In this paper, there are a lot of existing problems in the commercialization of Li-Fi being used in Wi-Fi, and a comparative analysis.

• Journal of information and communication convergence engineering
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• v.10 no.2
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• pp.156-161
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• 2012

An increasing number of people who use a smart phone or tablet PC are accessing wireless networks in public facilities including cafes and shopping centers. For example, iPhones and Android Phones have been available since 2010. However, security incidents may occur through all sorts of malicious code infection of users' personal information during the use of an insecure wireless network. In this paper, we will describe the Wi-Fi protected access (WPA) and WPA2 encryption systems used to access a wireless network from a smart phone and tablet PC, and demonstrate the access point (AP) hacking process in a wireless network to which a password is applied on the basis of the analyzed WPA and WPA2 passwords. We will analyze the method of successful AP hacking and propose an approach to enhancing wireless LAN security. This study will contribute to enhancing the security and stability of wireless networks.

• Journal of Convergence Society for SMB
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• v.2 no.1
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• pp.51-58
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• 2012

Android platform is a powerful operating system developed on Linux 2.6 Kernel, and provides many features such as comprehensive libraries, a multimedia environment, and powerful interface for phone applications. Since Android is an open operating system, which can be installed in any vendors's equipments. Current smartphones as well as netbooks, navigations, car PCs, tablet PCs, Industrial PCs are used in various fields. It is difficult a lot that to mount to other devices on the Android platform or new devices. In this Paper, The process that data that occurred from a hardware was passed to the highest application and Android platform system for managing hardware devices were analyzed. Building Android & driver compilation environment, How to support the protocol for the use of WiFi in the kernel, How to Mount a WiFi device in the kernel, Device driver registration for the Android platform, WiFi Management Service Daemon (wpa_supplicant) and IP allocation services daemon (dhcpcd) registration, How to create a socket for communication between the daemon (wpa_supplicant) and HAL have been presented. In the experiment using the proposed method, WiFi devices were mounted on the Android platform in the X-86 & ARM family. Understanding the whole process of control flow in Android hierarchy is very important to porting a new device on it. The process included in this paper can help technicians who might encounter the obstacles in their porting works.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1143-1150
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• 2017

In this paper, we proposed a method to display a hazard warning of hacking in the UX(: User Experience) concept level for non experts in the open Wi-Fi access area. According to the dangers of the AP raised by capture, we developed an application that provides a warning pop-up on the danger of hacking before using for APs that are distinguished by color and selected.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.411-413
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• 2012

It is noticeable that the number of newly registered Android applications increases rapidly. Such a recent trend indicates the Android platform is spreading globally. The ongoing platform upgrade might be one of the main reasons of the popularity of the Android mobile platform. Android platform 4.0 or later provides WiFi-Direct APIs that allow smart devices to communicate with each other without intermediate media. In this paper, we propose design and implementation techniques for small-scale impromptu meeting applications based on WiFi-Direct. The proposed meeting application can be used in a situation when one is difficult to connect the Internet. It also provides meeting data sharing capabilities, noting functionality, real-time remote screen control, and grouping of meeting participants. Our development results have demonstrated that the Android WiFi-Direct APIs can be effectively applied to impromptu conferencing mobile applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.879-888
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• 2017

Recently, the Smart household appliances to provide Smart services have been actively spreaded by providing IoT(Internet of Things). Also, the appliances which Wi-Fi and Bluetooth can directly control are preferred. But until now, the most household appliances are based on IR(InfraRed) and the each procotols of them are different. In this paper, to solve these problems, we suggested the system to control both smart appliances and general appliances by using Smart phone. The system is "Wi-Fi to IR" gateway which receives the Wi-Fi signal to convert to IR signal and transmit it. Also, we made the remote control function in specific brands' appliances possible to most brands without limitation and tried to control not only one remote controller for one TV brand but also for all brand without limitation.

• Journal of electromagnetic engineering and science
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• v.18 no.1
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• pp.58-62
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• 2018

In this study, we propose a software-defined radio-based frequency interference emulator in the space-time domain. This emulator can easily model actual interference environments because of the versatile programming capability of the universal software radio peripheral and LabVIEW. As an example of an interfering network using the contention-based multiple access scheme in the time domain, we emulate a coordinated Wi-Fi network that consists of one access point and two Wi-Fi nodes. Results show that our emulator can successfully model multiple interfering signals in the Wi-Fi network and easily adjust various space-time domain parameters.

• Journal of the Korea Society of Computer and Information
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• v.22 no.6
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• pp.123-129
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• 2017

In this paper, we proposed a smart multiple-tap system which a remote user with smartphone can control multiple-taps in order to reduce standby-power consumption more conveniently when plugged-in electric appliances are turned-off. Recently, several researches of smart multiple-tap using IoT technology has reported. However, in these researches, an additional device like as a server computer is necessary, or multiple-taps could be only remotely controlled by smartphone and not directly controlled by on/off switch. The proposed smart multiple-tap system does not need any additional device only if it has a WiFi router, and it can be used for user as well as remote control using smartphone application and physically direct control using contact switches like existing multiple-taps. Our approach is to develop a smart multiple-tap device capable of WiFi communication can each serve as a server or a client, and can be operated by the hybrid switch combining the on/off contact switch and the relay switch. We implemented the prototype of the proposed system composed of the smart multiple-tap device and the smartphone application, and the test of the prototype validates the proposed system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1792-1798
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• 2017

Event Data Recorder(Car Black-Box) with WiFi dongle have been released, and the platform of the majority is the Linux platform. This is because the platform development is possible in little investment cost by reducing the source licensing costs by taking advantage of the open source. But utilizing Linux platform has the limitations of boot-up time and consuming processing power due to the limitation of battery capacity, to be cost-competitive to minimize the use of memory. In this paper, the real-time operating system(RTOS) is utilized to optimize these portions. MP4 encoder and Muxer are developed to be about ten seconds boot up and minimized memory. It has the advantages of operating at lower power consumption than the Linux utilizing WiFi dongle. Utilizing a WiFi dongle is to provide a progressive download feature on smart phones to lower product prices. But RTOS has the weakness in WiFi. Porting TCP /IP, Web and DHCP server and combination with the USB OTG Host interface by implementing the protocol stack are developed for WiFi. And also SPI NOR flash memory is utilized for faster boot time and cost reductions, low processing power to be consume. As the results, the developed proved the 10 seconds booting time, 24 frame rate/sec. and 10% lower power consumption.