• Journal of KIISE:Computing Practices and Letters
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• v.7 no.6
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• pp.602-613
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• 2001

Recently, the computing has developing in distributed object computing environment for supporting a programming paradigm of distributed application requiring interoperability between heterogeneous clients and servers. It involves the complex networking and the object-oriented technologies for various multimedia application service. In this paper, we construct the real-time object group platform for solving the difficulties of managements of distributed objects and the real-time constraints by requiring for real-time service supporting of applications in distributed computing environment. The existing researches are being tried to only improving the performance of systems by using real-time CORBA itself, or modifying the part of CORBA compliance. Hence, we design a new model of real-time object group platform that can support the real-time requirement without modifying the ORB. The structure of our real-time object group analyzed and defined the requirement about object management and real-time application service sides. And the role of the components of real-time object group is divided into 2 classes for reducing the side effect of interoperability between management and service. Also, we considered how to transparently express the parameters of real-time properties for clients and developers of server's service objects. If the expression of real-time parameters is transparent, then the developer can easily extend the real-time parameters simply and flexibly. Therefore, in this paper we defined the role of components of platform and described functions of each component and designed and then implemented the real-time object group platform. Finally, we showed the execution procedures of implemented our platform for verifying the functionality.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.43-51
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• 2016

Preventing the forgery and alteration of test reports is important, in order to maintain the reliability of military supplies. Based on a survey of reports on testing institutions and a case study of established electronic document systems in the public sector, we propose a system architecture, which helps prevent the forgery and alteration of test reports with legal force. The proposed architecture takes advantage of both the time stamp that records the time a document is received and a server synchronized with the testing institution. Using the proposed system architecture, the user is able to request a test and receive reports from the testing institution without delay. Also, a defense agency is able to conveniently prove the authenticity of the test reports and utilize the statistical data collected by the architecture. Therefore, we expect that the proposed system architecture will help defense agencies to prevent the forgery and alteration of test reports and ensure their reliability and quality.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.6
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• pp.646-661
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• 2003

It is not easy that we visualize the large volume data stored in the every client computers of the web environment. One solution is as follows. First we compress volume data, second store that in the database server, third transfer that to client computer, fourth visualize that with direct-volume-rendering in the client computer. In this case, we usually use wavelet transform for compressing large data. This paper reports the experiments for acquiring the wavelet bases and the compression ratios fit for the above processing paradigm. In this experiments, we compress the volume data Engine, CThead, Bentum into 50%, 10%, 5%, 1%, 0.1%, 0.03% of the total data respectively using Harr, Daubechies4, Daubechies12 and Daubechies20 wavelets, then visualize that with direct-volume-rendering, afterwards evaluate the images with eyes and image comparison metrics. When compression ratio being low the performance of Harr wavelet is better than the performance of the other wavelets, when compression ratio being high the performance of Daubechies4 and Daubechies12 is better than the performance of the other wavelets. When measuring with eyes the good compression ratio is about 1% of all the data, when measuring with image comparison metrics, the good compression ratio is about 5-10% of all the data.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.6
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• pp.699-711
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• 2003

Home networking and Internet control technologies must satisfy three requirements with a view to being applied to home for raising the qualify of human life. Firstly, the cost of adding home networking ability to the traditional appliance must be minimized. Secondly, the mutual accessibility between home network and Internet must be guaranteed in the various Internet service environment of home. Finally, communication must be possible between the home network and the Internet that use different communications protocols. This paper proposes the ARCS (Appliance Remote Control System) that controls appliances based on LnCP (Living network Control Protocol) via the Internet. LnCP is the most cost-effective network and control protocol for home network. ARCS guarantees the accessibility from the Internet to home network and provides users with the virtual interface designed for controlling appliances using the Internet application program. In addition, this paper proposes AICS (Appliance Internet Control Specification). AICS, is based on LnCP, defines the message structure and control commands for the Internet control communication. ARCS and home gateway are developed to meet AICS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5294-5302
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• 2014

The development of public-key-based technique that enables a variety of services(E-government, e-banking, e-payment, etc.) evaluated as having complete safety. On the other hand, vulnerabilities(e.g, heartbleed bug, etc.) are constantly being discovered. In this paper, a public key infrastructure to verify the safety and reliability, the collision rate using OpenSSL key pair was analyzed. the experiment was performed using the following procedure. Openssl was used to create five private certification agencies, and each of the private certificate authority certificates to create 2 million, generating a total of 10 million by the certificate of the key pair conflicts analysis. The results revealed 35,000 in 1 million, 0.35% chance of a public key, a private key conflict occurred. This is sufficient in various fields(E-payment, Security Server, etc.). A future public-key-based technique to remove the threat of a random number generator, large minority issues, in-depth study of selection will be needed.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.3
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• pp.224-234
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• 2005

As the network-related technology develops the number of both Internet users and the usage are explosively increasing. The networking traffic is increasing in the campus as the networking system inside universities, following the trend, adds more nodes and various networking services. Nonetheless, the quality of services for users has been degraded. Accordingly, core problems, which can cause troubles for network management, design and expansion of the network, and the cost policy, has appeared. To effectively cope with the problems with analyses a great number of technicians, tools, and budget are needed. However, it is not possible for mid and small-sized colleges to spend such a high expenditure for professional consulting. To reduce the cost and investment creating the optimized environment, the analyses on the replacement of the tools, changing the network structure, and performance analysis about capacity planning of networking is necessary. For this reason, in this paper, framework-based performance management tools are used for all steps that are related to the subject of the analysis for the network management. As the major research method, the current data in detailed categories are collected, processed, and analyzed to provide the solution for the problems. As a result we could manage the network, server, and application more systematically and react efficiently to errors and degrading of performance that affect the networking tasks. Also, with the scientific and organized analyses the overall efficiency is upgraded by optimizing the cost for managing the operation of entire system.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.6
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• pp.1-10
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• 2005

This paper describes the implementation of HTML converter for wireless internet access in wireless application protocol environment. The implemented HTML converter consists of the contents conversion module, the conversion rule set, the WML file generation module, and the frame contents reformatting module. Plain text contents are converted to WML contents through one by one mapping, referring to the converting rule set in the contents converting module. For frame contents, the first frameset sources are parsed and the request messages are reconstructed with all the file names, reconnecting to web server as much as the number of files to receive each documents and append to the first document. Finally, after the process of reformatting in the frame contents reformatting module, frame contents are converted to WML's table contents. For image map contents, the image map related tags are parsed and the names of html documents which are linked to any sites are extracted to be replaced with WML contents data and linked to those contents. The proposed conversion method for frame contents provides a better interface for the users convenience and interactions compared to the existing converters. Conversion of image maps in our converter is one of the features not currently supported by other converters.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.39 no.6
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• pp.53-67
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• 2002

The multimedia synchronization is one of the key issues to be resolved in order to provide a good quality of multimedia related services, such as Video on Demands(VoD), Lecture on Demands(LoD), and tele-conferences. In this paper, we introduce an adaptive multimedia synchronization algorithm using the level of buffers and load of servers, which are modeled and analyzed by ExSpect, a Petri net based simulation tool. In the proposed algorithm, the audio and video buffers are divided to 5 different levels, and the pre-defined play-out speed controller tries to make the buffer level to be normal in different temporal relations between multimedia streams using buffer levels and server loads. Because each multimedia packet is played by the pre-defined play-out speed, the media data can be reproduced within the permissible limit of errors while preserving the level of buffers to be normal. The proposed algorithm is able to handle and support various communication restrictions between providers and users, and offers little jitter play-out to many users in networks with the limited transmission capability. The performance of the developed algorithm is analyzed in various network conditions using a Petri net simulation tool.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.1
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• pp.54-61
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• 2007

In this paper, on-demand service streaming protocol for user-created contents in digital cable broadcasting environment is considered. In order to provide variety media contents service like UCC in digital cable broadcasting environment, the same service model as RVOD(Real Video on Demand) is required and the different interface for each broadcasting platform is needed in a current OCAP environment. Using return path based RTP, we separate existing VOD stream band into broadcasting and VOD stream band. In order to broaden On-demand service, consistent expansion of the infrastructure same as live broadcasting system is inefficient in the digital cable broadcasting environment. Using existing network protocol, the service which is insensitive to the infrastructure for VOD service becomes possible. Therefore we considered the analysis of the class of download available structure in the Set-Top-Box for RTP(Real-time Transport Protocol) and designing the decoding available streaming server for UCC transcoding and transmission in the receiver. Designing a efficient VOD service and system under the broadcasting environment gives a expansion of On-Demand service and more chance to upload and utilization of contents.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.4 s.316
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• pp.42-47
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• 2007

To reduce the chattering errors of reed switch sensors in the automatic remote measurement of water meter a reed switch sensor was analyzed and improved. The operation of reed switch sensors can be described as a mechanical contact switch by approximation of permanent magnet piece to generate an electrical pulse. The reed switch sensors are used mostly in measurement application to detect the rotational or translational displacement. To apply for water flow measurement devices, the reed switch sensors should keep high reliability. They are applied for the electronic digital type of water flow meters. The reed switch sensor is just mounted simply on the conventional mechanical type flow meter. A small magnet is attached on a pointer of the water meter counter rotor. Inside the reed sensor two steel leaf springs make mechanical contact and apart repeatedly as rotation of flow meter counter. The counting electrical contact pulses can be converted as the water flow amount. The MCU sends the digital flow rate data to the server using the wireless communication network. But the digital data is occurred difference or won by chattering noise. The reed switch sensor contains chattering error by it self at the force equivalent position. The vibrations such as passing vehicle near to the switch sensor installed location causes chattering. In order to reduce chattering error, most system uses just software methods, for example using filter algorithm and also statistical calibration methods. The chattering errors were reduced by changing leaf spring structure using mechanical characteristics.