• The KIPS Transactions:PartC
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• v.17C no.1
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• pp.27-36
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• 2010

In Web registration pages and online polling applications, CAPTCHA(Completely Automated Public Turing Test To Tell Computers and Human Apart) is used for distinguishing human users from automated programs. Text-based CAPTCHAs have been widely used in many popular Web sites in which distorted text is used. However, because the advanced optical character recognition techniques can recognize the distorted texts, the reliability becomes low. Image-based CAPTCHAs have been proposed to improve the reliability of the text-based CAPTCHAs. However, these systems also are known as having some drawbacks. First, some image-based CAPTCHA systems with small number of image files in their image dictionary is not so reliable since attacker can recognize images by repeated executions of machine learning programs. Second, users may feel uncomfortable since they have to try CAPTCHA tests repeatedly when they fail to input a correct keyword. Third, some image-base CAPTCHAs require high communication cost since they should send several image files for one CAPTCHA. To solve these problems of image-based CAPTCHA, this paper proposes a new CAPTCHA based on both image and text. In this system, an image and keywords are integrated into one CAPTCHA image to give user a hint for the answer keyword. The proposed CAPTCHA can help users to input easily the answer keyword with the hint in the fused image. Also, the proposed system can reduce the communication costs since it uses only a fused image file for one CAPTCHA. To improve the reliability of the image-text fusion CAPTCHA, we also propose a dynamic building method of large image dictionary from gathering huge amount of images from theinternet with filtering phase for preserving the correctness of CAPTCHA images. In this paper, we proved that the proposed image-text fusion CAPTCHA provides users more convenience and high reliability than the image-based CAPTCHA through experiments.

• Journal of the Korea Society of Computer and Information
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• v.17 no.2
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• pp.197-206
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• 2012

A exisiting recommedation system using association rules has the problem, such as delay of processing speed from a cause of frequent scanning a large data, scalability and accuracy as well. In this paper, using a Implicit method which is not used user's profile for rating, we propose the personalized recommendation system which is a new method using the FP-tree mining based on RFM. It is necessary for us to keep the analysis of RFM method and FP-tree mining to be able to reflect attributes of customers and items based on the whole customers' data and purchased data in order to find the items with high purchasability. The proposed makes frequent items and creates association rule by using the FP-tree mining based on RFM without occurrence of candidate set. We can recommend the items with efficiency, are used to generate the recommendable item according to the basic threshold for association rules with support, confidence and lift. To estimate the performance, the proposed system is compared with existing system. As a result, it can be improved and evaluated according to the criteria of logicality through the experiment with dataset, collected in a cosmetic internet shopping mall.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.6
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• pp.27-35
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• 2005

While the current world wide network offers an incredibly rich base of information, it causes network management problem because users should have many independent IDs and passwords for accessing different sewers located in many places. In order to solve this problem users have employed single circle of trust(COT) ID management system, but it is still not sufficient for clearing the problem because the coming ubiquitous network computing environment will be integrated and complex networks combined with wired and wireless network devices. The purpose of this paper is to describe the employment and evaluation of federated ID interoperability method for solving the problem. The use of the proposed model can be a solution for solving network management problem in the age of mobile computing environment as well as wired network computing environment.

• Journal of the Korea Society of Computer and Information
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• v.26 no.2
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• pp.229-235
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• 2021

Blockchain, recognized as one of the core technologies of the 4th industrial revolution, is an Internet-based distributed data management system which does not require centralized control. Blockchain is characterized by the integrity and reliability of information, and blockchains can be used where such characteristics are required. Typical applications of blockchain include finance, transaction, and evaluation management. In this paper, we designed a blockchain-based evaluation management system that allows users to freely create and manage evaluation instances. Evaluation managers can create an evaluation instance according to their purpose and allocate evaluation items and evaluators. When the evaluators finish evaluating the evaluation items, the evaluation manager can aggregate the evaluation results for the instance. Someone, who want to perform evaluation for various purposes but do not have an evaluation system, can implement the evaluation system relatively simply by using this system. In addition, due to the characteristic of the blockchain, evaluators cannot modify the evaluation scores they have already recorded, and neither the system administrator nor the evaluation administrator can modify the evaluation scores. For this reason, the reliability of the evaluation increases.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.37-41
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• 2020

In this paper, we propose a routing method to improve the message transmission efficiency between DTN nodes in an environment where communication infrastructure in the city is destroyed. In the situation where a certain size of communication infrastructure can not function, the message transmission process between the nodes is explained. An effective routing method for improving reliability between nodes was proposed and evaluated using DTN simulator. The routing algorithm with improved reliability in urban areas was confirmed by simulation considering the message transmission relationship between nodes on uncertain path due to the destruction of communication infrastructure. We used a routing algorithm that includes all the contact information the node has experienced in the past. In the simulation of delivering messages in a situation where the communication infrastructure was destroyed, relatively better results were obtained than the existing routing algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.199-205
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• 2014

We would like to study and develop the optimized WBS(Work Breakdown Structure) considering project's range, schedule, cost and human resources management with defining phased work in main task and preceding and escorting relationships for effective small and medium enterprises' informatization through standardized PSDM(Production System Development Methodology). For more systemic and effective system built-up, it introduces production information with WBS study which is appropriate for the small and medium enterprises with setting up management items for enhancing system's reliability, quality, productivity, smooth communication among the participated enterprises such as the small and medium enterprises, IT enterprises, and supervision enterprises, and operational support including maintenance of the built system. This study is purpose of helping a lot of the small and medium enterprises and IT enterprises to build up the systems more effective and reliable within planned schedule using the standardized methodology.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.113-119
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• 2008

Conventional 1-1-1 cooperative protocol offers path-loss gain as advantage of multi-hop and spatial diversity which is equivalent to MIMO system. This protocol is enable to get higher reliability and reduction of power consumption than those of the single-hop or multi-hop. But the 1-1-1 cooperative protocol get only the diversity order 2 and limited path-loss reduction gain because this protocol has a single cooperative relay. We propose 1-2-1 cooperative protocol using two cooperative relays R1, R2. The 1-2-1 cooperative protocol can improve path-loss reduction and increase diversity order 3. Moreover, the cooperative relay R2 attains diversity order 2. The signaling method in transmission uses DF (Decode and Forward) or DR (Decode and Reencode) and 1-2-1 DF/DR cooperative protocol are applied to clustering based wireless sensor networks (WSNs). Simulations are performed to evaluate the performance of the protocols under Rayleigh fading channel plus AWGN (Additive White Gaussian Noise).

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.55-62
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• 2016

Recently, users choosing a restaurant basedon information provided by blogs are increasing significantly. However, those of most blogs are unreliable since domestic restaurant blogs are occupied by advertising postings written by 'power bloggers'. Thus, in order to ensure the reliability of blogs, it is necessary to filter the advertising blogs which are sometimes false or exaggerated. In this paper, we propose the method of distinguishing the advertising blogs utilizing an automatic classification technique. In the proposed technique, we first manually collected advertising restaurant blogs, and then analyzed features which are commonly found in those blogs. Using the extracted features, we determined whether a given blog is advertising one applying automatic classification algorithms. Additionally, we select the features and the algorithm which guarantee optimal classification performance through comparative experiments.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.5
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• pp.41-46
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• 2021

Due to the development of private education and changes in the educational environment, the need for an academy management system is emerging for various tasks of academy management in the community and mobile environment with students. However, solutions developed for existing academy tasks, such as attendance management for students, announcement, and instructor management to sponsors, are specialized and specialized in large academy, making it difficult to use in small and medium-sized academy. Also, there are problems that are not suitable for most academy and cannot reflect various requirements of institutes because of the high cost. In order to solve these problems, this paper designed a B2M-based academy management system that can quickly improve information processing, improve credibility, and reduce the cost of processing tasks based on optimized functions such as academic administration and manager management, attendance management, and student management.

• Journal of Internet of Things and Convergence
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• v.9 no.1
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• pp.41-47
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• 2023

Today, due to the increase in global population growth, the international community is discussing solving the food problem. The aquaculture industry is emerging as an alternative to solving the food problem. For the innovative growth of the aquaculture industry, smart fish farms that combine the fourth industrial technology are recently being distributed, and full-cycle digitalization is being promoted. Water quality sensors, which are important in the aquaculture industry, are electrochemical portable sensors that check water quality individually and intermittently, making it impossible to analyze and manage water quality in real time. Recently, optically-based monitoring sensors have been developed and applied, but the reliability of monitoring data cannot be guaranteed because the state information of the water quality sensor is unknown. Therefore, this paper proposes an algorithm representing self-diagnosis status such as Failure, Out of Specification, Maintenance Required, and Check Function based on monitoring data collected by water quality sensors to ensure data reliability.