• The Journal of Korean Association of Computer Education
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• v.15 no.6
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• pp.53-64
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• 2012

This study was to compare and analyze actual conditions and awareness of high school students' mobile learning. Survey was used as a research method and percentile, t-test and F-test were conducted for the statistical analyses. Results revealed that in the case of actual conditions on mobile device and mobile learning, slight differences were shown in various sub-variables, depending on independent variables (gender, grade, track); year 2010 can be the most important year for the mobile learning; high school students seldom utilize mobile learning in a small piece of time; mobile learning using Apps was not widespread yet. In the case of awareness of mobile learning, statistically significant differences were found in the use capacity of mobile devices, the increase of learning performance, and the continual interests of mobile devices.

• Journal of Information Technology Services
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• v.13 no.4
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• pp.245-254
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• 2014

Payment system is defined as the various contracts and operating facilities for the transfer of monetary value to clear the relationship between credit and debt. Payment systems essentially require the efficient and reliable operations. Card-based payment systems are developed practically and creatively in accordance with the progress of ICT. Especially in mobile environment with intelligent mobile devices such as smart-phones and tablets, a variety of payment services are provided. Existing card-based payment services are configured by the payment transaction initiated by the merchants card acceptance and then swiping into the CAT (Card Authorization Terminal) to begin the transaction. The merchant initiated payment services are now applied to the Wireless CAT (W-CAT) for mobile environment. That kind of payment services cause many problems such the illegal card information leaks and the lingering threat of W-CAT theft. Also, the use of many W-CATs increased cost to the merchant. In this paper, we propose the card holder initiated card payment system using the intelligent mobile devices in mobile environment for solving problems of the existing merchant initiated card payment system and coping effectively with the activation of a wireless data network and changes of information technology.

• Proceedings of the CALSEC Conference
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• 2005.11a
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• pp.78-84
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• 2005

As the research activities related to 'Ubiquitous Computing' whose concept was introduced by Mark Weiser are growing, RFID(Radio Frequency Identification) technology has recently gained attention as a technology to advance the ubiquitous computing and a lot of related researches are also in progress. Research works done so far are mainly linked to the situation that the research outputs apply to meet the requirements for asset tracking and data sharing with partners over supply chain by using fixed RFID readers. However, it is essential that users have access to real-time information about the tagged objects and services whenever and wherever they want in the era of ubiquitous computing, so mobile devices-including PDA, smart phone, cellular phone, etc - which are equipped with an RFID reader can be regarded as an essential terminal for users living in ubiquitous computing environment. As far as the application with mobile devices are concerned, there are many considerations due to their limited capabilities of data processing, battery consumption and so on. In this paper, we review the generic RFID network model and introduce the revised RFID network model in consideration of incorporation with mobile devices equipped with an RFID reader. Also, we derive the requirements for software embedded within an RFID- enabled mobile terminal and then discuss essential components for implementation. Moreover, we develop the applications for asset management at museum by using mobile RFID network model.

• Smart Media Journal
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• v.1 no.4
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• pp.8-17
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• 2012

In this paper, we introduce the appoaches that aim to improve user experience in mobile device by the use of multiple vibration signal feedback, conducted by Haptics and Virtual Reality laboratory at POSTECH. We introduce current progresses of our 'Vibrotactile flow using multiple vibration actuators' and 'Real-time dual-channel haptic music player.' The 'Vibrotactile flow using multiple vibration actuators' produces vibrotactile flow sensations by using multiple actuators and that improves the information transfer on mobile devices. The 'Real-time dual-channel haptic music player' generates vibrotactile sensation by transforming auditory signal, which improves the user experience of mobile devices. These approaches can be good examples to fulfill the demands of better information transfer capability and user experience on mobile devices.

• ETRI Journal
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• v.33 no.4
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• pp.476-486
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• 2011

The quality of navigation service is determined by the accuracy of the available data. For existing navigation services, a full map update is provided in order to keep the map data of mobile devices current. As content and services of mobile devices have recently been diversifying, the size of map data managed in mobile devices has increased, reaching several gigabytes in size. It generally takes tens of minutes to write several gigabytes of data into mobile device storage. For traditional navigation systems, a complicated storage structure called a physical storage format (PSF) is used to assure maximum processing performance of map data in mobile devices within limited resources. Consequently, even though modified navigation map data actually affects only a portion of a map, the full map data is updated because partial updates are not possible. In this paper, a navigation system is studied to solve this difficult partial map update problem. The map air update navigation system, which is the result of this study, provides real-time partial map updating using wireless communications.

• Journal of Korea Multimedia Society
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• v.12 no.12
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• pp.1778-1786
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• 2009

Many sensor network applications have been developed for smart home, disaster management, and a wide range of other applications. These applications, however, generally assume a fixed base station as well as fixed sensor nodes. Previous research on sensor networks mainly focused on efficient transmission of data from sensors to fixed sink nodes. Recently there has been active research on mobile sink nodes, sink mobility is one of the most comprehensive trends for information gathering in sensor networks, but the research of an environment where both fixed sink nodes and mobile sinks are present at the same time is rather scarce. This paper proposes a scheme for context-aware by ubiquitous devices with the sink functionality added through fixed sinks under a previously-built, cluster-based multi-hop sensor network environment. To this end, clustering of mobile devices were done based on the fixed sinks of a previously-built sensor network, and by using appropriate fixed sinks, context gathering was made possible. By mathematical comparison with TTDD routing protocol, which was proposed for mobile sinks, it was confirmed that performance increases by average 50% in energy with the number of mobile sinks, and with the number of movements by mobile devices.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.1
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• pp.62-70
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• 2002

The purpose of this paper in that users can use mobile device applications more easily and efficiently through MoDAM (Mobile Device Application Management) system. MoDAM automates the process of web retrieval for obtaining mobile device applications and the process of installing or updating it on mobile devices and then supply users with these automated services in a step form by combining two separated processes. We implement a web agent conforming to OSD (Open Software Description) specification for automating software retrieval and downloading and also a mobile device based software management module conforming to SyncML (Synchronization Markup Language) specification for synchronizing common data between server and client. The method of automated software retrieval and management for mobile devices using these standard specifications minimizes users' interrupts and also can be applied to traditional several different mobile devices, operating systems or downloading web sites without platform dependent considerations.

• 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.

• IEIE Transactions on Smart Processing and Computing
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• v.1 no.1
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• pp.65-71
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• 2012

Mobile RFID is a new application that uses a mobile phone as an RFID reader with wireless technology and provides a new valuable service to users by integrating RFID and ubiquitous sensor network infrastructures with mobile communication and wireless Internet. Whereas the mobile RFID system has many advantages, privacy violation problems on the reader side are very concerning to individuals and researchers. Unlike in regular RFID environments, where the communication channel between the server and reader is assumed to be secure, the communication channel between the backend server and the RFID reader in the mobile RFID system is not assumed to be safe. Therefore it has become necessary to devise a new communication protocol that secures the privacy of mobile RFID-enabled devices. Recently, Lo et al. proposed a mutual key agreement protocol that secures the authenticity and privacy of engaged mobile RFID readers by constructing a secure session key between the reader and server. However, this paper shows that this protocol does not meet all of the necessary security requirements. Therefore we developed an enhanced mutual key agreement protocol for mobile RFID-enabled devices that alleviates these concerns. We further show that our protocol can enhance data security and provide privacy protection for the reader in an unsecured mobile RFID environment, even in the presence of an active adversary.

• KIISE Transactions on Computing Practices
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• v.21 no.12
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• pp.762-767
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• 2015

An Internet of Things (IoT) is a system where various "things" are connected to each other via a wired/wireless network, and where information is gathered, processed, and interchanged/shared. One of the important actors in IoT is a mobile IoT device (such as a smartphone or tablet). These devices tend to consume a large amount of power in order to provide various high performance application services; however, as the devices cannot be supplied with power all the time, efficient power management is necessary. Power management of mobile IoT devices involves complex relationships between various entities such as application processors (APs), HW modules inside/outside AP, operating systems, mobile IoT platforms, and applications. In order to develop power-efficient mobile IoT devices, a method is needed to systematically analyze these relationships and manage power based on a clear understanding of them. To address this problem, software engineering principles for the development of power-efficient mobile IoT devices are presented in this paper. The feasibility of the proposed principles have been validated in the domain of smartphone camera power management.