• Annual Conference of KIPS
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• 2009.04a
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• pp.1292-1295
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• 2009

최근 인터넷 사용량이 급증함으로 인해 인터넷 응용프로그램의 개발, 종류 및 사용이 기하급수적으로 늘어나고 있다. 초기에 사용되었던 웹, 파일전송, E-mail 등 well-known port 기반 서비스가 변화되어 unwell-known port 기반 서비스가 주를 이루고 있다. 이러한 상황에서 효율적인 네트워크 관리를 위한 응용 트래픽의 분류가 어려워지고 있으며, 효과적인 트래픽 분류를 위한 연구가 많이 진행되고 있다. 본 논문에서는 가장 많이 사용되는 인터넷 응용프로그램인 웹하드를 대상으로 이들로부터 발생하는 트래픽을 분석하였다. 먼저 웹하드의 정의 및 기능과 그 종류에 대해서 기술하였다. 또한, signature 기반 분류 방법으로 웹하드 트래픽을 패킷 캡쳐 툴과 Flow 을 이용하여 분석하고 그 결과로부터 응용 트래픽 분류의 관점에서의 웹하드 트래픽의 특징에 대해서 기술하였다.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.2
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• pp.49-58
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• 2018

A certificate is a means to certify users by conducting the identification of the users, the prevention of forgery and alteration, and non-repudiation. Most people use an accredited certificate when they perform a task using online banking, and it is often used for the purpose of proving one's identity in issuing various certificates and making electronic payments in addition to online banking. At this time, the issued certificate exists in a file form on the disk, and it is possible to use the certificate issued in an existing device in a new device only if one copies it from the existing device. However, most certificate duplication methods are a method of duplication, entering an 8-16 digit verification code. This is inconvenient because one should enter the verification code and has a weakness that it is vulnerable to security issues. To solve this weakness, this study proposes a method for enhancing security certificate duplication in a multi-channel using TCP and BLE. The proposed method: 1) shares data can be mutually authenticated, using BLE Advertising data; and 2) encrypts the certificate with a symmetric key algorithm and delivers it after the certification of the device through an ECC-based electronic signature algorithm. As a result of the implementation of the proposed method in a mobile environment, it could defend against sniffing attacks, the area of security vulnerabilities in the existing methods and it was proven that it could increase security strength about $10^{41}$ times in an attempt of decoding through the method of substitution of brute force attack existing method.

• Journal of KIISE:Databases
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• v.32 no.3
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• pp.263-275
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• 2005

In a large DNA database, indexing techniques are widely used for rapid approximate sequence searching. However, most indexing techniques require a space larger than original databases, and also suffer from difficulties in seamless integration with DBMS. In this paper, we suggest a space-efficient and disk-based indexing and query processing algorithm for approximate DNA sequence searching, specially exact match queries, wildcard match queries, and k-mismatch queries. Our indexing method places a sliding window at every possible location of a DNA sequence and extracts its signature by considering the occurrence frequency of each nucleotide. It then stores a set of signatures using a multi-dimensional index, such as R*-tree. Especially, by assigning a weight to each position of a window, it prevents signatures from being concentrated around a few spots in index space. Our query processing algorithm converts a query sequence into a multi-dimensional rectangle and searches the index for the signatures overlapped with the rectangle. The experiments with real biological data sets revealed that the proposed method is at least three times, twice, and several orders of magnitude faster than the suffix-tree-based method in exact match, wildcard match, and k- mismatch, respectively.