• Journal of Internet Computing and Services
• /
• v.13 no.3
• /
• pp.1-16
• /
• 2012

Cost-effective mobility management for the roaming mobile users is very important in the seamless services on next-generation wireless network (NGWN). MIPv6 (Mobile IPv6) is one of the mobility management schemes proposed by the IETF (The Internet Engineering Task Force) and various IPv6-based mobility management schemes have been developed. They are directly involved with data transfer from MN (Mobile Node). In this paper, two kinds of schemes in analyzing of mobility management schemes are proposed. The signaling transfer and packet delivery procedures for each mobility management schemes are analyzed, respectively. The signaling cost for mobility management schemes are calculated, and the cost of each protocol are analyzed numerically. In other word, applying the sum of signaling cost and packet delivery cost to each mobility management scheme, their costs are analyzed. Finally, our performance evaluation results that the network-based mobility management scheme shows better performance in terms of overall cost.

• Journal of Korean Library and Information Science Society
• /
• v.45 no.4
• /
• pp.365-390
• /
• 2014

This study intend to find the application methods of the FRBR model about legislation by analyzing a law life cycle from the enactment to the amendment and abolition of legislation and the type of the change after abolition. The legislation is the work as an aggregate entity consisting legal provisions and each provision is also the work. They are in the Whole-to-Part relation. The legislation has a effect by being published in the official gazette, and the updated text or the translated text is not the official version. Even if the name of the legislation is changed, it is treated as the same entity when it is not abolished and the simple rectifying text expressed in the official gazette is also legally valid. The Libraries Act has been replaced by the Libraries Act(old version), the Libraries Promotion Act, the Libraries and Reading Promotion Act and the Libraries Act(new version) in the order named, and it can be bounded into a superwork. For these examples, we provided the application method of FRBR model and suggested the actual application cases regarding Work, Expression, Manifestation and Item which are in Group 1 of FRBR model for the Libraries Act.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.48 no.7
• /
• pp.537-546
• /
• 2020

The reliability used as a performance indicator during the development of space launch vehicle should be validated by the launch success probability, and the launch data need to be fed back for reliability management. In this paper, the launch data of space launch vehicles around the world were investigated and statistically analyzed for the success probabilities according to the launch vehicle models and maturity. The Bayesian estimation of launch success probability was reviewed and analyzed by comparing the estimated success probabilities using several prior distributions and the statistical success probability. We presented the method of generating prior distribution function and considerations for Bayesian estimation.

• Journal of KIISE:Computer Systems and Theory
• /
• v.37 no.1
• /
• pp.8-18
• /
• 2010

Traditional storage server suffers from duplicated data blocks which cause an waste of storage space and network bandwidth. To address this problem, various de-duplication mechanisms are proposed. Especially, lots of works are limited to backup server that exploits Contents-Defined Chunking (CDC). In backup server, duplicated blocks can be easily traced by using Anchor, therefore CDC scheme is widely used for backup server. In this paper, we propose a new de-duplication mechanism for improving a storage system. We focus on efficient algorithm for supporting general purpose de-duplication server including backup server, P2P server, and FTP server. The key idea is to adapt stride scheme on traditional fixed block duplication checking mechanism. Experimental result shows that the proposed mechanism can minimize computation time for detecting duplicated region of blocks and efficiently manage storage systems.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.3
• /
• pp.475-482
• /
• 2001

In this paper, I describe the implementation of the distributed lists based on socket and on RMI(Remote Method Invocation). First, I describe and implement an interface of distributed list based on socket using object stream in a distributed environment, when encapsulating the message in the distributed list. Second, the major purpose to implement a distributed list in RMI is to compare advantages and disadvantages with other networking mechanisms by implementing complicated applications. The major advantage in using RMI is to implement simply the programs without using application-level protocol. In terms of program efficiency, the applications using HMI can degrade the performance due to many TCP/IP connections generated every update. TCP/IP connection requires much less cost than RMI. Even though RMI has the mechanism processing many method calls using a sing]e network connection, RMI is less efficient than the direct use of socket. However, RMI makes it possible to communicate beyond firewall using HTTP proxying mechanism. Consequently, I present a modeling of networking mechanism in finding out optimization solution by comparing and analyzing the two systems.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.3
• /
• pp.663-668
• /
• 2016

Without the interference of man in traditional single-device control system P2M way to control the device by a person to the development of the Internet of Things it was changing the way the M2M communication between devices possible. The attention of the user on the IoT to this development, but this increase was caused problems the system is insufficient to help the understanding of the IoT technologies to meet them. Therefore, to understand the operation of the IoT technology system that can easily expressed is required. In this paper, we design and implement a simulation system that can monitor the process of relationships between devices, such as when a user event occurs, the sensor, SNS and the XML-based collaboration to meet users' needs. Further, the respective functions for the maintenance and updating of the simulation system is proposed to make API.

• KIPS Transactions on Software and Data Engineering
• /
• v.6 no.9
• /
• pp.445-456
• /
• 2017

In this paper, we propose a method to detect spam tweets containing unhealthy information by using an n-gram dictionary under limited labeling. Spam tweets that contain unhealthy information have a tendency to use similar words and sentences. Based on this characteristic, we show that spam tweets can be effectively detected by applying a Naive Bayesian classifier using n-gram dictionaries which are constructed from spam tweets and normal tweets. On the other hand, constructing an initial training set requires very high cost because a large amount of data flows in real time in a twitter. Therefore, there is a need for a spam detection method that can be applied in an environment where the initial training set is very small or non exist. To solve the problem, we propose a method to generate pseudo-labels by utilizing twitter's retweet function and use them for the configuration of the initial training set and the n-gram dictionary update. The results from various experiments using 1.3 million korean tweets collected from December 1, 2016 to December 7, 2016 prove that the proposed method has superior performance than the compared spam detection methods.

• Journal of Convergence for Information Technology
• /
• v.8 no.1
• /
• pp.201-206
• /
• 2018

Recently, as technologies for realizing artificial intelligence have become more common, machine learning is widely used. Machine learning provides insight into collecting large amounts of data, batch processing, and taking final action, but the effects of the work are not immediately integrated into the learning process. In this paper proposed an adaptive learning model to improve the performance of real-time stream analysis as a big business issue. Adaptive learning generates the ensemble by adapting to the complexity of the data set, and the algorithm uses the data needed to determine the optimal data point to sample. In an experiment for six standard data sets, the adaptive learning model outperformed the simple machine learning model for classification at the learning time and accuracy. In particular, the support vector machine showed excellent performance at the end of all ensembles. Adaptive learning is expected to be applicable to a wide range of problems that need to be adaptively updated in the inference of changes in various parameters over time.

• Journal of Convergence for Information Technology
• /
• v.8 no.1
• /
• pp.139-145
• /
• 2018

Ransomeware is a kind of malware. Computers infected with Ransomware have limited system access. It is a malicious program that must provide a money to the malicious code maker in order to release it. On May 12, 2017, with the largest Ransomware attack ever, concerns about the Internet security environment are growing. The types of Ransomware and countermeasures to prevent cyber terrorism are discussed. Ransomware, which has a strong infectious nature and has been constantly attacked in recent years, is typically in the form of Locky, Petya, Cerber, Samam, and Jigsaw. As of now, Ransomware defense is not 100% free. However, it can counter to Ransomware through automatic updates, installation of vaccines, and periodic backups. There is a need to find a multi-layered approach to minimize the risk of reaching the network and the system. Learn how to prevent Ransomware from corporate and individual users.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.40 no.11
• /
• pp.957-962
• /
• 2012

Fluid/structure interaction (FSI) analysis is necessary to predict the response of a system in which aerodynamic pressure causes deformation of the structure, and vice versa. In dealing with a nonlinear behavior of the structure, however, a simple iterative algorithm of aerodynamic analysis with structural analysis yields no accurate results since aerodynamic pressure need to be changed in accordance with the deformation of structures. In this study, we explore an efficient and accurate method for integrating FSI analysis into structural nonlinear systems. During the course of nonlinear structural analysis, loading conditions are periodically updated by aerodynamic analysis. The accuracy and efficiency of the method is demonstrated with a high-aspect-ratio flexible wing of Global Hawk.