• Proceedings of the Korean Society of Computer Information Conference
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• 2022.01a
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• pp.123-126
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• 2022

본 논문에서는 철도 교량 운행 상황을 가정하는 모형 철도를 사용하여 실제 철도 교량에서 발생할 수 있는 소음, 진동등 위험 요소로 분류될 수 있는 데이터들을 수집하고 수집된 데이터들을 활용하여 실시간으로 위험 요소로부터 발생할 수 있는 위험 상황들을 분류하고 적절한 조치들을 상황에 맞게 취할 수 있도록 한다.

• Journal of Broadcast Engineering
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• v.5 no.2
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• pp.176-187
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• 2000

MPEG-4 is a digital bit stream format and associated protocols for representing multimedia content consisting of natural and synthetic audio, video and object data. This paper describes an application where multiple audio/visual data stream are combined in MPEG-4 and transported via MPTG-2 transport streams(TS). Also, this paper describes how to convert MPEG-4 Over MPEG-2 TS bit streams into MP4 file which Is designed to contain the media information of an MPEG-4 presentation in a flexible, extensible format. MPEG-4 is presented in the form of audio-visual objects that are arranged into an audio-visual scene by means of a scene descriptor and is composed of the audio-visual objects by means of an object descriptor. These descriptor streams are not defined MPEG-2 TS. So. this paper focuses on handling of these descriptors and parsing TS streams to get MPEG-4 data. The MPEG-4 Over MPEG-2 TS to MP4 format converter is implemented in the demonstrated systems.

• The KIPS Transactions:PartD
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• v.9D no.5
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• pp.945-954
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• 2002

Clickstream is the information which demonstrate users' path through web sites. Analysis of clickstream shows how web sites are navigated and used by users. Clickstream of online web sites contains effective information of web marketing and to offers usefully personalized services to users, and helps us understand how users find web sites, what products they see, and what products they purchase. In this paper, we present an extended web log system that add to module of collection of clickstream to understand users' behavior patterns In web sites. This system offers the users clickstream information to database which can then analyze it with ease. Using ADO technology in store of database constructs extended web log server system. The process of making clickstreaming into database can facilitate analysis of various user patterns and generates aggregate profiles to offer personalized web service. In particular, our results indicate that by using the users' clickstream. We can achieve effective personalization of web sites.

• Journal of KIISE:Databases
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• v.33 no.2
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• pp.163-174
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• 2006

In distributed wireless sensor network, it is difficult to transmit and analyze the entire stream data depending on limited networks, power and processor. Therefore it is suitable to use alternative stream data processing after classifying the continuous stream data. We propose a classification framework for continuous multivariate stream data. The proposed approach works in two steps. In the preprocessing step, it takes input as a sliding window of multivariate stream data and discretizes the data in the window into a string of symbols that characterize the signal changes. In the classification step, it uses a standard text classification algorithm to classify the discretized data in the window. We evaluated both supervised and unsupervised classification algorithms. For supervised, we tested Bayesian classifier and SVM, and for unsupervised, we tested Jaccard, TFIDF Jaro and Jaro Winkler. In our experiments, SVM and TFIDF outperformed other classification methods. In particular, we observed that classification accuracy is improved when the correlation of attributes is also considered along with the n-gram tokens of symbols.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.5
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• pp.137-145
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• 2003

Nowadays, people can communicate with each other on any time at my place by development of wireless communications. But, the openness of mobile communications Poses serious security threats and the security is necessary on mobile communications to support the secure communication channel. The most commonly method is stream cipher for mobile communications. Generally, this stream cipher is implemented by LFSR(Linear Feedback Shift Register). On this paper proposes the modified mechanism of the S box is usually used in block cipher to advance security og the stream cipher and this mechanism is the modified three one in consideration og the randomness. Generally, S box that is function with nonlinear property makes data more strong by attack. The randomness test of the proposed algorithm is used Ent Pseudorandom Number Sequence Test Program and by the test result it proves that it has better randomness and serial correlation value than the based stream cipher on respective test.

• Journal of Korea Multimedia Society
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• v.8 no.1
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• pp.71-78
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• 2005

When a PDA is used as a mobile terminal in an infrastructure network based on 802.11b standard wireless LAN, we measured and evaluated the performance of multimedia data transmission. In general, PDAs are mainly used tot receiving bulk data like multimedia data. However, while a PDA as a mobile host transfers multimedia data to a desktop PC as a fixed host in such a network, the time taken to receive data from the PC to the PDA is always longer than the time taken to send data from the PDA to the PC by at least 53%. Thus, we consider some critical factors that affect the time taken to receive Our experimental results show that with the PDA the time taken to access a file for writing is longer than the time taken to access a file for reading of to 4.11 times. In addition, a dramatic change of the site of the receiver window, from 686 bytes to 32,383 bytes, prolongs the time taken to receive. To transfer data without any inter-packet interval for the PDA and to increase the size of the TCP receive buffer will be effective in improving the delay to receive data.

• The KIPS Transactions:PartD
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• v.15D no.2
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• pp.247-256
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• 2008

In the ubiquitous environment, it is scattered all over our neighboring in many smart objects. These smart objects constantly produce the information and the amount of the generated information is massive. As the internet search engine came out to help us to find the useful data from the sea of the information connected to the internet, the sensor data stream processing middleware is appearing to make us to develop the ubiquitous service easily by extracting the meaningful information from the massive sensor data and delivering the extracted information to the application which makes our life convenient. We have to inform the information relating to the provided service to a middleware so that the ubiquitous service can be provided by using sensor data stream processing middleware. In this paper, we classify the information which is needed to express the ubiquitous service which uses sensor data for the service providing. And we propose a distinct markup language called Context-driven Service Markup Language (CSML) to effectively describe this information. We can easily express the various ubiquitous services which have to be provided in the various situations using proposed CSML.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.3
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• pp.515-520
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• 2022

In context awareness using multiple sensors, when using sensor data detected and sent by each sensor, it is necessary to give different weights for each sensor. Even if the same type of sensor is configured for the same situation, sometimes it is necessary to assign different weights due to other secondary factors. It is inevitable to assign weights to events in the real world, and it can be said that a weighting method that can be used in a context awareness system using multiple sensors is necessary. In this study, we propose a weighting method for each sensor that reports to the host while the sensors continue to detect over time. In most IoT environments, the sensor continues the detection activity, and when the detected value shows a change pattern beyond a predetermined range, it is basically reported to the host. This can be called a kind of data stream environment. A weighting method was proposed for sensing data from multiple sensors in a data stream environment, and the new weighting method was to select and assign weights to data that indicates a context change in the stream.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.04a
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• pp.1178-1183
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• 2000

기존의 MuX 시스템은 분산환경에서 멀티미디어 데이터를 전송하기 위해서 PUSH 방식의 데이터 전송기법만을 제공한다. PUSH 방식의 데이터 전송기법은 자료 발생매체 중심의 데이터 전송기법으로 멀티미디어 데이터가 발생할 때 바로 자료 사용 매체로 전송하는 기법이다. PUSH 방식 데이터 전송 기법은 네트웍 대역폭이 크고 시스템 자원이 풍부한 경우 간단히 연출 QoS를 만족시킬 수 있다. 그러나 네트웍의 대역폭이 좁은 시스템에서는 PUSH 방식 데이터 전송기법으로 연출 QoS를 만족시키는데 한계가 있다. 이러한 문제를 해결하기 위해 PULL 방식 데이터 전송기법을 제안하였다. PULL 방식 데이터 전송기법은 자료 사용 매체 중심의 데이터 전송 기법으로 자료 사용 매체의 요구시점에 요구한 만큼의 데이터를 발생시켜 그 매체로 전송하는 방법이다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.683-686
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• 2010

무선 센서 네트워크(Wireless Sensor Network) 환경에서의 작고 상이한 많은 센서들은 물리적 공간에서 서로 통신하며 끊임없이 데이터 스트림을 생성한다. 이런 센서는 측정 데이터와 센서를 표현하는 메타데이터로 구성되어 있다. 메타데이터는 센서의 측정 간격, 위치, 타입, 측정 단위 등의 중요한 정보를 내포하고 있다. 무선 센서는 메타데이터를 관리하기 위한 명확한 표준안의 제시 없이 독자적인 기준을 적용함으로써, 상이한 센서 간에 데이터 수집 및 통합에 어려움이 뒤따른다. 이런 문제점을 해결하기 위하여 본 논문에서는 상이한 센서 간 메타데이터를 효율적으로 통합, 관리하기 위해 OGC(Open Geospatial Consortium)에서 제시한 SensorML(Sensor Model Language)을 기반으로 상이한 메타데이터를 표준화된 형식으로 표현하고, 이를 토대로 메타데이터 관리 시스템을 설계한다.