• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.18-26
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• 2011

According that smart phones have been widely used, their users can easily access various information around the devices through location information services equipped to the smart phone devices. In this paper, we propose a WeWhere which is a system of client-server model for providing the current location among several smart phone users in real time. A client-side smartphone user send to a server his/her current location obtained by applying location information service provided from smart phones and receive location information of all smartphone users connected to the user from the server. The all location information is displayed on a smartphone of a user in client-side and users can track location of their related users. All most 200,000 persons in the world have used the proposed system, WeWhere, normally without overloading of a server system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.526-529
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• 2015

as the smartphone industry developed, the smartphone's internal hardware devices have become high-end devices and it requires more power consumption than the previous one. therefore a battery of high capacity needed, but there is a limit in order to equip a large battery on account of smartphone minimization. The Linux Kernel provides the DVFS Mechanism to compensate for these limitations by software techniques. DVFS is dynamically adjust the frequency of the CPU to reduce the power consumption of the CPU. ondemand governor, the default policy in DVFS, apply the maximum frequency of the CPU whenever exceeding the up_threshold. so it result in a waste of CPU resources. by paying attention to this point, this paper propose the mechanism that maintain a high CPU utilization in proportion to the current frequency of the cpu to prevent the waste of CPU resources and conserve energy.

• Journal of Korea Multimedia Society
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• v.15 no.1
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• pp.101-107
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• 2012

Real time information on disaster situation is very important in disaster prevention effort. Generally, disaster related organizations use mobile devices to collect various disaster informations of disaster site. However, current disaster collection systems do not provide effective functionality to connect with another disaster information system. Therefore, disaster-related organizations have to make smartphone application for collection and administration of disaster information and then connect it with another information system. If this system is commercialized, vulnerability of previous system can be complemented. Thus, this paper focused on designing a prototype system for information collection and management in disaster site using smartphone applicatiom.

• Journal of Positioning, Navigation, and Timing
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• v.9 no.3
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• pp.273-284
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• 2020

The performance of Global Navigation Satellite System (GNSS) chipset and Inertial Measurement Unit (IMU) sensors embedded in smartphones for location-based services (LBS) is limited due to the economic reasons for their mass production. Therefore, it is necessary to efficiently process the output data of the smartphone's embedded sensors in order to derive the optimum navigation values and, as a previous step, output performance of smartphone embedded sensors needs to be verified. This paper analyzes the navigation performance of such devices by processing the raw measurements data output from smartphones. For this, up-to-dated versions of smartphones provided by Samsung (Galaxy s10e) and Xiaomi (Mi 8) are used in the test experiment to compare their performances and characteristics. The GNSS and IMU data are extracted and saved by using an open market application software (Geo++ RINEX Logger & Mobile MATLAB), and then analyzed in post-processing manner. For GNSS chipset, data is extracted from static environments and verified the position, Carrier-to-Noise (C/N₀), Radio Frequency Interference (RFI) performance. For IMU sensor, the validity of navigation and various location-based-services is predicted by extracting, storing and analyzing data in static and dynamic environments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.9
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• pp.4560-4575
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• 2018

Since smartphone contains various personal data, security is one of the important aspects in smartphone technologies. Up to now, various authentication techniques have been proposed to protect smartphones. The pattern lock on the Android system is one of the most widely used authentication methods for low-cost devices but it is known to be vulnerable to smudge attack or shoulder surfing attack. LG's smartphone uses its own technique, which is called "Knock Code." The knock code completes the authentication by touching the user defined area in turn on the screen. In this paper, we propose the new, enhanced version of knock code by adding the sliding operation and by using flexible area recognition. We conducted security analysis, which shows that under the same password size, the search space is overwhelmingly larger than the original algorithm. Also, by using the sliding operation, the proposed scheme shows resilience against smudge attacks. We implemented the prototype of our scheme. Experimental results show that compared with the original Knock Code and Android pattern lock, our scheme is more convenient while providing better security.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.4
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• pp.43-53
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• 2020

There are three standards for FIDO1 authentication technology: Universal Second Factor (U2F), Universal Authentication Framework (UAF), and Client to Authenticator Protocols (CTAP). FIDO2 refers to the WebAuthn standard established by W3C for the creation and use of a certificate in a web application that complements the existing CTAP. In Korea, the FIDO certified market is dominated by UAF, which deals with standards for smartphone (Android, iOS) apps owned by the majority of the people. As the market requires certification through FIDO on PCs, FIDO Alliance and W3C established standards that can be certified on the platform-independent Web and published 『Web Authentication: An API for Accessing Public Key Credentials Level 1』 on March 4, 2019. Most PC do not contain biometrics, so they are not being utilized contrary to expectations. In this paper, we intend to present a model that allows login in PC environment through biometric recognition of smartphone and FIDO UAF authentication. We propose a model in which a user requests login from a PC and performs FIDO authentication on a smartphone, and authentication is completed on the PC without any other user's additional gesture.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.18-23
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• 2016

Internet of things (IoT) is revolutionizing in the patient-Centered medical monitoring and management by authorizing the Smartphone application and data analysis with medical centers. The network connectivity is basic requirement to collect the observed human beings' health information from Smartphone to monitor the health from IoT medical devices in personal healthcare. The IoT environment built in Smartphone is very effective and does not demand infrastructure. This paper presents the smart phone deployed personal IoT architecture for Non-Invasive ECG Capturing. The adaptable IoT medical device cum Gateway is used for personal healthcare with big data storage on cloud configuration. In this approach, the Smartphone camera based imaging technique used to extract the personal ECG waveform and forward it to the cloud based big data storage connectivity using IoT architecture. Elaborated algorithm allows for efficient ECG registration directly from face image captured from Smartphone or Tablet camera. The profound technique may have an exceptional value in monitoring personal healthcare after adequate enhancements are introduced.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.139-146
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• 2014

This paper proposes a new personalized mobile advertising service using a smartphone connected with a digital signage which is increasingly common for out-of-home advertising. The advertising contents can be transferred with their metadata to a digital signage. Then, the signage delivers only metadata to smartphones in close proximity of it. Based on the user's preference, an application on a smartphone stores advertising metadata and publishes a personalized advertising e-catalog automatically. A smartphone user can browse, edit and share it with friends. In the view of extension of the reach of the advertising contents of various N-Screen devices including a digital signage and a smart TV to a smartphone and supplying personalized advertising data, this advertising model will be very beneficial and commercialized in the near future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2999-3004
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• 2013

Smartphone subscribers exceeded 30 million people, Smart Korea is up on this track, and leaping to 'Smart powerful nation from 'IT powerful nation. Of course, the popularization of the smart phone called 'PC in the hands' has brought a revolutionary change to nation livelihood, and also to business and government, too. The current usage of Smartphone is not just a simple function call, people can communicate anytime, anywhere with it. The current usage of Smartphone is not just a simple function call, people can communicate anytime, anywhere with it. And it has become the culture of the terminal type in the hands whenever and wherever. However, the screen size and the existing flash or video files do not run when trying to access to the homepage for PC with Smartphone. and it may gives the inconvenience to people who use mobile devices. Therefore, in this paper, it is a study for the provision of an efficient service for Smartphone users through the establishment of website for mobile in mobile circumstances.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.4
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• pp.93-98
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• 2023

Recently, as the size of display devices tends to increase and taking pictures with smart phones has become commonplace, the need for taking high-resolution pictures with smart phones is increasing. However, when the lens size of a camera is limited, such as in a smartphone, there is a physical limit to increasing the resolution of a photo. This paper is about a technique for increasing the resolution of a picture even when using a small-sized lens like a smartphone camera. It is to take multiple pictures while moving the smartphone, and to increase the resolution by combining these pictures into one picture. First of all, two pictures were taken while moving the smartphone horizontally for the 2D picture. Processes such as camera matrix estimation, and homograph inverse transformation were performed using OpenCV, and the resolution was improved by synthesizing one picture. It was confirmed that the resolution was improved in parts such as oblique lines or arcs on several test pictures.