• Proceedings of the CALSEC Conference
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• 2001.08a
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• pp.637-649
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• 2001

ㆍ Research Method - Experimental Design ㆍWhen Entity Bean is deployed and Client request to inquire a specific information of Doctor Table, we experiment Total Time for Query Execution according to Time Measurement Operation in Client code. ㆍWe can apply the statistics for the experiment to the design of Entity Beans.(omitted)

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.246-249
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• 2005

본 논문에서는 4세대 이동통신을 위한 적응부호화 하이브리드 ARQ 시스템 모델을 제안하고, 제안 시스템의 성능을 분석 검토 하였다. 또한 적응 하이브리드 시스템의 프레임 효율도 분석하였다. 결과로부터 제안 시스템이 성능이나 효율에서 우수함을 확인 할 수 있었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.8
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• pp.1123-1132
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• 2018

In this paper, we design and implement a public bicycle sharing system based on smart phone application capable of distributing access codes via internet connection. When smartphone user uses the application to request a bicycle unlock code, server receives the request and sends an encrypted code, which is used to unlock the bicycle at the station and the same code is used to return the bicycle. The station's hardware prototypes were built on top of Internet devices such as raspberry pi, arduino, keypad, and motor driver, and smartphone application basically includes shared bike rental and return functionality. It also includes an additional feature of reservation for a certain time period. We tested the implemented system, and found that it is efficient because it shows the average of 3-4 seconds delay. The system can be implemented to manage multiple bikes with a single control box, and as the user can use a smartphone application, this makes the system more cost effective.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.121-125
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• 2007

This paper proposes automatic generation method of proxy client code to automation of web service selection process through a monitoring agent. The technique of this paper help service consumer to provide source code of proxy client as it bring an attribute value of specific element of WSDL document using template rule. Namely, a XSLT script file provide code frame of dynamic invocation interface model. The automatic code generation technique need to solving starvation status of selection architecture. It is required to creating request HTTP message for every service on the result of search. The created proxy client program code generate dummy message about services. The proposed client code generation method show us a possibility of application in the automatic generation programming domain.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.13-16
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• 2001

In the Dedicated Short Range Communication (DSRC) system channel, a large number of bit errors occur because of Additive White Gaussian Noise (AWGN) and fading. When an image data is transmitted under the condition, reconstructed image quality is significantly degraded. In this paper, as an alternative to the error correcting code and/or automatic repeat request scheme, we propose an error recovery scheme for image data transmission. We first analyze how transmission errors in the DSRC system channel degrade image quality. Then, in order to improve image quality, we propose error resilient and concealment schemes for still image transmission using DCT-based fixed length coding, hamming code, cyclic redundancy check, and interleaver. Finally, we show its performance by an experiment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.324-330
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• 2006

The next generation mobile communication systems require error correcting schemes that can be adaptable to various code rates and lengths with negligible performance degradation. Serial concatenated convolutional codes can be a good candidate satisfying these requirements. In this paper, we propose new rate-compatible punctured serial concatenated convolutional code (RCPSCCC) which performs better than the RCPSCCC proposed by Chandran and Valenti in the sense of the rate compatibility. These codes are evaluated and analyzed by using computer simulation and SNR evolution technique. As their application, Type-II hybrid automatic repeat request (HARQ) schemes using both RCPSCCCs are constructed and new RCPSCCC is shown to have better throughput.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2A
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• pp.187-194
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• 2004

We propose priority-based reservation code multiple access (P-RCMA) which can enhance voice traffic quality of the previous RCMA. The proposed protocol maintains two power levels and consider traffic characteristics in contending shared available codes to transmit packets. P-RCMA gives priority to the voice request packets rather than data packets by capture effect at the receiver part of base station. We show numerical results from EPA (equilibrium point analysis) analysis and simulation study in terms of voice packet dropping probability and average data packet transmission delay.

• Journal of The Korean Association of Information Education
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• v.14 no.1
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• pp.13-23
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• 2010

In recent creativity becomes a new request in the knowledge and information age. Robot programming education is an effective teaching method for improvement of creativity. Existing robot programming tools includes text-based or GUI-based development environment. Most of programming tools provide a simple tutorial system without interactive activity for beginners. In this paper, we propose an online robot programming education system based on web2.0, which embedded collaborative code creating tool, interactive tutorial chat and video conference tool to support collaborative code creating via web 2.0. Knowledge sharing tool allows users to share their collaborative source code. Besides, it makes users gained the experience and knowledge of program designing efficiently.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12C
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• pp.1222-1230
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• 2005

We aim at increasing the throughput of the hybrid automatic retransmission request (HARQ) protocol in Space-Time (ST) coded multi-antenna transmission systems. By utilizing reliability information at the decoder, we obtain an improved probability of successful decoding, which enhances the overall system throughput at low-complexity. Simulations and analytical results demonstrate the performance of our scheme in impulse noise environment as well as AWGN and fading multi-input multi-ouput (MIMO) channels.

• Journal of Information Technology Services
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• v.19 no.3
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• pp.57-73
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• 2020

The proportion of digital evidence in criminal cases has increased, while at the same time, the spread of the Internet has made it easy to delete information that is stored in another place and thus, the Internet is being used to delete online criminal evidence. To respond quickly and effectively to cybercrime, 29 countries signed the Convention on Cybercrime in 2001 through the Council of Europe. Article 16 of the Convention relates to the expedited preservation of stored computer data and requires signatories to adopt legislative measures to enable its competent authorities to order expeditious preservation of specified computer data where there are grounds to believe that the data is particularly vulnerable to loss or modification. More than 60 countries have joined the Convention since 2001 and have made efforts to improve their legal system in line with it. The United States legislated 18 U.S.C. § 2703(f) to preserve electronic evidence pending the issuance of a court order. The German Code of Criminal Procedure §§ 94~95 allows prosecution authorities to seize evidence or issue production orders without court control in urgent circumstances. A custodian shall be obliged to surrender evidence upon a request that evidence be preserved, and non-compliance results in punishment. Japan legislated the Criminal Procedure Act § 197(3) and (4) to establish a legal base for requesting that electronic records that are stored by an ISP not be deleted. The Korean Criminal Procedure Act § 184 outlines procedures for the preservation of evidence but does not adequately address the expeditious preservation of digital evidence that may be vulnerable to deletion. This paper analyzes nine considerations, including request subjects, requirements, and cost reimbursement to establish directions to improve the legal system for the expedited preservation of digital evidence. A new method to preserve online digital evidence in urgent cases is necessary.