• Proceedings of the Korea Multimedia Society Conference
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• 2003.11a
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• pp.445-448
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• 2003

During a time when cellular systems are being deployed in massive scale worldwide, international roaming is becoming increasingly important. This paper presents UIM (User Identification Module) for mobility support, authentication, and service portability between different mobile systems. We also introduce network model based on PASM(Portable Authentication and Mobility Service Machine) which will support signaling protocol and user information conversions with database for roaming between different mobile networks. Stored data types and elements in UIM, logical data structure and configuration, and registration procedures are described here in the case of DCN (Digital CDMA (Code Division Multiple Access) Network System) and GSM (Global System for Mobile Communications).

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.813-820
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• 2008

We have developed inventory database program which is available in the mobile PC. The mobile PC is convenient in terms of portability, data input, modification, practicality of various program and data confirmation in site. By utilizing the inventory database program in mobile PC, we are able to complete database in site. Then, database is converted into the Hangul document and Excel worksheet. Also, based on the above procedure, effective management and utilization of inventory on cut-slope can be achieved.

• Journal of Digital Convergence
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• v.11 no.3
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• pp.293-298
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• 2013

We consider about software quality nowadays. The company considers about software quality more and more compare to software development. We analyze the software testing data in this paper. We find the software effect according to the number of testing, the number of testing date, the number of fault according to characteristics. Also, we analyze the result by regression. Also, we propose the testing effect by sex.

• Journal of information and communication convergence engineering
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• v.11 no.4
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• pp.253-257
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• 2013

Mobile computers can process large amounts of data at high speeds, and it is feasible and easy to implement a remote monitoring system utilizing mobile computers. Because of their portability and convenience, these computers have been employed in various research areas to develop such monitoring systems. Existing monitoring system is a bit difficult to real time monitoring the scattered offshore facilities. So this paper compensate the existing system by using mobile computers such as a tablet PC-based monitoring system. Also, the scattered offshore facilities can be monitored in real-time through the tablet PC. The developed monitoring system is a fully Internet-based monitoring platform that enables one to monitor and control remote oceanic applications at any time and any place where it is possible to access the Internet. It can be applied to many oceanic applications as well as the unmanned systems and remote monitoring systems on land.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.341-356
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• 2007

We study factors that affect consumers' switching behaviors among service providers in Korean mobile telecommunications service market. For empirical analysis, quarterly time series data from the first quarter of 2004 through the second quarter of 2007 were used. We chose the number of switchers to each mobile service provider in each quarter as dependent variables. Independent variables include acquisition costs per subscriber, which play the role of subsidy to mobile handset, switching costs, time trend, structural change effect, and standby demand effects. Through the empirical analysis, we found that different providers' churn-in customers are affected by different factors. Specifically, the number of chum-in customers into SK Telecom is explained mainly by SK Telecom's customer acquisition costs and standby demand from KTF, while the number of customers switching into KTF is better explained by switching costs from the previous service provider and standby demand from SK Telecom. Those who chose LG Telecom as their new provider, on the other hand, were mainly attracted by LG Telecom's high subscriber acquisition cost.

• The KIPS Transactions:PartB
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• v.13B no.5 s.108
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• pp.569-578
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• 2006

The present study implemented AAC(Augmentative and Alternative Communication) system using images that speech defectives can easily understand. In particular, the implementation was focused on the portability and mobility of the AAC system as well as communication system of a more flexible form. For mobility and portability, we implemented a system operable in mobile devices such as PDA so that speech defectives can communicate as food as ordinary People at any Place using the system Moreover, in order to overcome the limitation of storage space for a large volume of image data, we implemented the AAC system in client/server structure in mobile environment. What is more, for more flexible communication, we built an image dictionary by taking verbs as the base and sub-categorizing nouns according to their corresponding verbs, and regularized the types of sentences generated according to the type of verb, centering on verbs that play the most important role in composing a sentence.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.10
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• pp.912-920
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• 2012

In this paper, we propose a new and cost-effective RCP (Rapid Control Prototyping) system based on Matlab/Simulink and a DAQ (Data Acquisition) unit with the high speed USB communication interface. The proposed RCP system has a feature that a computer on which Simulink is running acts as a realtime controller and a DAQ unit performs data acquisition, transmission of the data to and from a computer, and the application of control data received from the computer. For its implementation, we develop 10 communication blocks each of which is constructed by using S-function. In order to increase the data communication speed and thus to reduce the sampling period of the overall control system, we propose to use a batch transfer strategy through the USB interface. The proposed RCP system has several advantages over existing methods such as good maintainability, portability due to the USB interface, low cost, and no necessity for C-code generation even though it can only be applied to control systems with moderate sampling rates. It is expected that the proposed RCP system can be useful in teaching control-related topics to undergraduate and graduate students.

• Journal of Information Technology Applications and Management
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• v.11 no.1
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• pp.189-200
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• 2004

Recently Flash Memory which is small and low-powered is widely used as a storage of embedded system, because an embedded system requests portability and a fast response. To resolve a difference of access time between a storage and RAM, Linux is using disk caching which copies a part of file on disk into RAM. It is not also an exception on embedded system. A READ access-time of flash memory is similar to RAMs. So, when a process on an embedded system reads data, it is similar to the time to access cached data in RAM and to access directly data on a flash memory. On the embedded system using limited memory, using a disk cache is that wastes much time and memory spaces to manage it and can not reflects the characteristic of a flash memory. This paper proposes the regular file access of limited using a page cache in the file system based on a flash memory and reflects the characteristic of a flash memory. The proposed algorithm minimizes power consumption because access numbers of the RAM are reduced and doesn't waste a memory space because it accesses directly to a flash memory Therefore, the performance improvement of the system applying the proposed algorithm is expected.

• Journal of Information Technology Applications and Management
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• v.11 no.1
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• pp.53-67
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• 2004

We propose an advanced transaction scheduling protocol to improve the concurrency and to guarantee the mobility for the mobile database management systems. Mobility, portability, and wireless link In mobile computing environment can cause certain drawbacks, and thus it is more difficult to solve the concurrency control problems. However, a locking scheme should be used to guarantee the data consistency and to prevent the data conflicts. It is well known that data consistency is guaranteed by standard transaction scheduling schemes like two-phase locking (2PL). It has two of operation, lock and unlock. But 2PL does not give solution for mobile system. Altruistic Locking (AL) and classifying transactions, we adapt, can give solution for the previous problems. AL, as an advanced protocol, has attempted to reduce delay effects associated with lock release moment by the use of donation. In this paper, we extend those approaches and classify the transactions to reduce delay effects of short-lived transaction caused by long-lived transaction. In addition, we show efficient solution for the case of disconnection occurrence. Our protocol, namely, Mobile Altruistic Locking (MAL) is shown to be efficiently used in order to reduce delay effects and to guarantee database consistency in a state of the slippery connection in mobile database systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.6
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• pp.1365-1369
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• 2013

Recently, the Personal Health Device(PHD) that measures various biometric data easily are highlighted for ensuring portability, scalability and interoperability among the device as well as needs for a standardization of managing information measured by. In this paper, we'd like to propose u-healthcare monitoring system that measure biometric data(Oxygen saturation, Body weight, ECG and Blood pressure) by PHD featured with transferring data into devices such as smartphone using Bluetooth Health Device Profile(HDP) based on the ISO/IEEE 11073.