• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.75-84
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• 2014

In order to solve the problems such as overload, single point of failure, non-optimized data path, and network scalability in conventional central mobility management protocols, distributed mobility management schemes have been continually studied in and around the IETF. In this paper, a network-based partially-distributed mobility management mechanism, pDMMv6, is suggested and the performance comparison with traditional protocols such as PMIPv6 and MIPv6 is made through simulation under the various user traffic environment. The simulation results include UDP packet delivery ratio, end-to-end packet delay, binding delay for registration signaling, CPU utilization in each node, and response delays in several server-client TCP applications such as web browsing, e-mail, telnet remote login, FTP file up/down-load, and database access.

• The Journal of Korean Institute for Practical Engineering Education
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• v.4 no.1
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• pp.72-79
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• 2012

Recently, the growth of the computer-related industries lead to the growth of the computer-aided education. Virtual training (VT) is one of the most interesting education methods. Many 3D models for the VT contents have been produced, but little research has been performed for the unified management system to promote the reuse of 3D models. This paper proposes the unified 3D model management system. The 3D model file formats are surveyed to find a format that can be easily used by many VT content production softwares. The 3D model files will be stored in a central DB server. The structure of the DB system will be designed for 3D models. The system provides an easy way to search and download a 3D model. With the proposed system, the reuse of 3D models is expected to be promoted.

• Journal of Korea Multimedia Society
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• v.13 no.1
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• pp.102-110
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• 2010

H.264 SVC(Scalable Video Coding) provides the advantages of low disk storage requirement and high scalability. However, a streaming server or a user terminal has to extract a bit stream from SVC file. This paper proposes a bit stream extraction method which can get the maximum PSNR value while date bit rate does not exceed the available network bandwidth. To do this, this paper obtains the information about extraction points which can get the maximum PSNR value offline and decides the spatial/temporal resolution of a bit stream at run-time. This resolution information along with available network bandwidth is used as the parameters to a bit stream extractor. Through experiment with JSVM reference software, we proved that proposed bit stream extraction method can get a higher PSNR value.

• The Journal of Society for e-Business Studies
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• v.8 no.2
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• pp.33-48
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• 2003

Wireless Internet, created through the merging of mobile communication with Internet technology, provides the advantage of mobility, but the restrictions of the mobile environment are deterring it from growing into a mass public service. Of the restricting factors of the wireless environment, narrow memory space creates the disadvantage of not being able to manage resources in mobile devices efficiently Because there is a limit to obtaining sufficient memory space from hardware made with consideration of portability, future devices will need to have a platform design with storage area extended from internal storage to external storage space. In this paper, we present a mobile agent that extends the memory space from only the inside of a mobile device to an external server making it possible to use data by on-line Run-time, and can also manage internal files efficiently. We have designed and implemented a RMS(Resources Management System) as a realization. Devices using the proposed RMS will be able to apply extended processes with the 'Mobile Space Extension' and will be benefited with optimal memory space through efficient internal file management.

• Journal of Korea Multimedia Society
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• v.15 no.8
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• pp.1004-1016
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• 2012

This paper proposes a mobile augmented reality system to provide detail information of the products using QR code included in them. In the proposed system, we perform the estimation of the camera pose using both of marker-based and markerless-based methods. If the camera can see the QR code, we perform the estimation of the camera pose using the set of rectangles in the QR code. However, if the QR code is out of sight, we perform the estimation of the camera pose based homography between consecutive frames. Moreover, the content of the augmented reality in the proposed system is made by using meta-data. Therefore, the user can make contents of various scenario using only meta-data file without modification of our system. Especially, our system maintains the contents as newly updated state by the on-line server. Thus, it can reduce the unnecessary update of the program.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.129-132
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• 2003

In this paper, which sees the Strong-ARM SA1110 it used the main CPU and RTP in VoIP system. It will be able to apply the information communication field it embodied. It used the Tynux_box2 with the hardware side and it composed a VOIP system. And it used the RTP which is a real-time protocol in software control portion. The development environment of the paper that used the Target board and a Linux PC for connection used the RS-232C, USB connection, Ethernet LAN. The VoIP the environment for a communication used the wave file in the substitution which changes analog signal with the digital signal. And For the communication of the both sides it used the socket. This paper explained the fact that against a general technique from the operation of VoIP system. Using the Embedded linux development board which explained an operational process of the RTP protocol.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.11
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• pp.103-104
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• 1992

Automatic transmission of data from the blood analyzer to the request site is one of the most important part in hospital computerization. We have developed a system to automatically transmit the data from the atrial blood gas analyzer. In this system, HOST computer, FILE server, LAN(Local Area Network), 3270 Emulator and Multi-port card were integrated. Also, 3 blood gas analyser(NOVA Inc., USA) were connected to a single multi-port card which is attached in a personal computer for data acquisition. When specimen is collected from sampling sites, it is transfered to the lab. After analysis, the result is transmitted to the personal computer via serial communication between machine and multi-port card using interrupt method. Then, the patient's information (Name, Sex, etc.) is obtained from the HOST computer througth the emulator. The combined data(patient information & lab data) is transmitted to the each request site via LAN automatically. From the collected data, patient's previous data could be reviewed, and it could be used for the various statistics and the flow chart for clinical research. Also, we found that this system reduces the personal labor.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.153-158
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• 1998

Since the mid-1990′s, researches on 3D GIS have been regarded as one of main issues both in the academic sites and commercial vendors; recently, some prototyped systems or the first versioned software systems of commercial basis are being reported and released. Unlike conventional 2D GIS, which consists in intelligent structured GIS or desktop GIS, every 3D GIS has its own distinguished features according to data structure-supporting capability, GIS-styled functionality, external database accessibility, interfacing extents with 2D GIS, 3D visualization/texture mapping ability, and so forth. In this study, technical aspects related to system development, SERI-Web3D GIS ver. 1.2, are explained. Main features in this revised 3D GIS can be summarized: 2-tier system model(client-server), VGFF(Virtual GIS File Format), internal GIS import, Feature manager(zoning, layering, visualization evironment), Scene manager(manage 3D geographic world), Scene editor, Spatial analyzer(Intersect, Buffering, Network analysis), VRML exporter. While, most other 3D GISes or cartographic mapping systems may be categorized into 3D visualization systems handling terrain height-field processing, 2D GIS extension modules, or 3D geometric feature generation system using orthophoto image: actually, these are eventually considered as several parts of "real 3D GIS". As well as these things, other components, especially web-based 3D GIS, are being implemented in this study: Surface/feature integration, Java/VRML linkage, Mesh/Grid problem, LOD(Level of Detail)/Tiling, Public access security problem, 3-tier architecture extension, Surface handling strategy for VRML.

• Journal of Digital Convergence
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• v.9 no.5
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• pp.225-233
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• 2011

Internet telephony is an Internet service which supports voice telephone using VoIP technology on the IP-based Internet. It has some advantages in that voice telephone services can be accompanied with multimedia services such as video communication and messaging services. Recently, the introduction of smart phones has led to a growth in social networking services and thus, the research and development of Internet telephony has been actively progressed and has the potential to become a replacement for the telephone service that is currently being used. In this paper we designed and implemented a recording system which records voice data of SIP-based Internet telephone's voice calls. It is developed on the linux system and has some features such as audio mixing of two in/out voice channels, live packet sniffing, and the ability to transfer mixed audio files to the log file server. These functions are implemented using various open source softwares. Afterwards, this VoIP recording system will be applied as a base technology to advanced services like a VoIP-based call center system.

• Journal of the Korea Computer Graphics Society
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• v.19 no.1
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• pp.11-20
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• 2013

This paper introduces a user interface for large 3D meshes in mobile systems, which have limited memory, screen size and battery power. A large 3D mesh is divided into partitions and simplified in multi-resolutions so a large file is transformed into a number of small data files and saved in a PC server. Only selected small files specified by the user are hierarchically transmitted to the mobile system for 3D browsing and rendering. A 3D preview in a pop-up shows a simplified mesh in the lowest resolution. The next step displays simplified meshes whose resolutions are automatically controlled by the user interactions. The last step is to render a set of detailed original partitions in a selected range. As a result, while minimizing using mobile system resources, our interface enables us to browse and display 3D meshes in mobile systems through real-time interactions. A mobile 3D viewer and a 3D app are also presented to show the utility of the proposed user interface.