• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5A
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• pp.487-493
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• 2008

In this paper, we consider coded layered space-time architecture in MIMO-OFDM channels. Vertical Bell Lab Layered Space-Time(V-BLAST) scheme employing ordered successive interference cancellation(OSIC) algorithm provides very high spectral efficiency with low computational complexity. However, the error propagation is a major drawback constraining the overall performance of the V-BLAST system significantly. Based on this problem, we derive an improved detector using soft bit log-likelihood ratio(LLR) value. Simulation results show that the proposed detector outperforms the conventional V-BLAST scheme under spatially uncorrelated as well as correlated fading channels.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.9
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• pp.56-62
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• 2004

Recently, necessity and usage of the teleoperation have been increased in various fields from industrial automation to home application. Also, the internet is considered as a strong candidate far the transmission media of signals. However, it has an irregular transmission time delay and causes critical problems such as instability and poor performance. This paper presents a practical internet teleoperation system with a streaming buffer system which makes a variable time delay fixed. Validity of the proposed system is demonstrated by implementing the embedded system on a HILS(hardware in the loop system) which models a two-wheel mobile robot.

• Korea Multimedia Society
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• v.1 no.1
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• pp.19-32
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• 1997

There are many kinds of predominant modes to transfer Multimedia information on internet in the world. Various methods are applied to get real time multimedia data as possible as we need. At the moment it is very difficult to use acceptable technologies for performe those methods effectively on the Networks. This paper gives the alternative directions and trends for research and development of multimedia transmission on the internet. ATM is one of the best mode to transfer mass-multimedia data at the high speed on the Broad-Band ISDN until now. And xDSL (xDigital Subscriber Line) is an excellent typical method on the PSTN (Public Switched Telephone Network) using old type telephone line. But they are not yet applied into the phase of practical use together this time. So this paper analyzes what we need and how to develop the multimedia transmission modes which we can send on the internet without a problem or any difficulty for our various multimedia information all the time under low cost and high speed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.395-398
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• 2004

This paper describes the implementation of an internet-based servo-control system with novel direct internet control architecture which is insensitive to the inherent internet time delay. The servo control system can be controlled by using a PC provided at a local site. However, a large internet time delay may make some control inputs distorted. Moreover, since it is acted by the number of the internet nodes and loads, this delay is variable and unpredictable. This system consists of servo mechanism and Ethernet control adapter. Intention of this paper is to reduce the expenses, to manage effectively for plant and to increase the productivity through linking each plant of several factories by TCP/IP and Ethernet, and then many control plants and manager minimize the needed work. Experiments are partially fulfilled using the Labview and Matlab.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.1-5
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• 2010

Nowaday in the ubiquitous environment, the real-time remote control and monitoring technology for power grids or a similar system provides service as a sharable and independent of time-location for various contents to get from sensors or cameras of the system. In this paper, we introduce the real-time monitor and control system for photovoltaic system to evaluate the system performance and to keep the maintenance by using IMS (Internet Management System). To prove the pragmatic use of IMS, we applied the IMS in water management system. We designed feasibly to control on remote site by web-browser. It guarantees a continuity of real-time information transferring by IMS.

• Journal of Family Resource Management and Policy Review
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• v.9 no.2
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• pp.111-126
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• 2005

The purpose of the study was to find out some actual states qualities of consumers using of online mall users, as well as the factors that affect consumer satisfaction. A survey for this research was formed in order to find the consumer group between the ages of 20 and 30 who have experiences shopping online. From August 5th, 2002 to August 24th 2002, 424 were actually used tot this research The major results of the research were as follows. First, out of the people of the ages 20 to 30, the average age of people that actually purchase the online products was 27.7, and most were either office workers or students. Most of these people have purchased more than S products within a year, and won. Furthermore, $71.9\%$ of the payments were made using credit cards. The average days of using the Internet per week was 5.4 days, the average duration of utilization was 4 years, the average hours spent per day was 2 hours and 9 minutes, and the average time spent on searching information was 31 minutes per day. These peoples ability to put Internet to a practical use, their ability to use the information effectively, and the dangers of the Internet have received 3.66, 3.99, and 3.14 points out of the 5-point scale. In addition, the information search using the Internet received 3_44 points, and the consumer satisfaction received a fairly high score of 3.33 points. Second, the information searching factors involving the society and the Interact have showed efficiencies in people that received university education, people that purchase more than 3 products online per year, people that spend more than 100,000 won per year, and the people that make use of the Internet more often. Third, the customer satisfaction on Internet malls was greater in people that purchase more than 3 products, spend more than 100,000 won per year, make effective uses of the Internet, and Dow about the importance of the information search of the Internet. Fourth, the factors that affect customer satisfaction were the effectiveness of the Internet for searching information, the dangers of the Internet, and the hours spent on the Internet. The more uses of the Internet one makes, the less dangers one encounters, and the less one spends time on the internet, the higher ones customer satisfaction is was proven by this research.

• Journal of Digital Convergence
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• v.13 no.9
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• pp.387-395
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• 2015

The aim of this study was to investigate effects of socio-demographic, household, social support, health-related factors on adolescent internet use time. Multiple regression analysis was conducted to examine factors affecting adolescent internet using time, and this study used the 2014 10th Korean Youth Health Risk Behavior On-line Survey data by Centers for Disease and Prevention. Results show that as for socio-demographic factors, being male, lower economic status, being middle school student, and having poor academic grade were; as for household factors, youth-led, one-parent, grandparent(s), multicultural, and North Korean defectors family were; as for social support factors, the absence of family support, the absence of friend support and the absence teacher support were; and as for health-related factors, less exercise, higher level of stress, and lower level of subjective happiness were associated with increased internet using time. Based on these results, convergent implications about effective intervention strategies that adolescents can use internet appropriately were discussed in the section of conclusion.

• Korean Journal of Health Education and Promotion
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• v.24 no.1
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• pp.75-91
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• 2007

Objectives: It is known that the majority of middle schoolers spend the substantial amount of time using the Internet. Despite the fact, little is known about which factors are related to an increase in Internet use and what could be the consequences of excessive Internet use. The aim of this study was to explore factors affecting an increase in Internet use among elementary schoolers representing the population of South Korean elementary schoolers. Method: Secondary data obtained from the Korea Youth Panel Survey were analyzed longitudinally. Results: The average minutes spent using the Internet was 73.43 in the first wave, and was 92.17 in the second wave. Also, the percentage of those who experienced illegal behaviors on the Internet was 22.86% in the first wave, and was 30.92% in the second wave. Second, increased Internet use was strongly associated with an attack tendency, depression, suicidal ideation, stress, and delinquent behaviors. Finally, gender(being female), and increased attacking tendency, and smoking experiences successfully predicted an increase in Internet use one year later. Conclusions: It is necessary to provide education programs to young people and to develop preventive strategies for them. Through providing education programs, children can form desirable attitudes regarding the Internet use. Through providing intervention strategies, children can prevent from experiencing negative consequences due to excessive Internet use.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2151-2154
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• 2003

Internet is deeply rooted in everyday life and many things are performed using internet in real-world, therefore internet users increased because of convenience. Also internet accident is on the increase rapidly. The security vendor developed security system to protect network and system from intruder. Many hackings can be prevented and detected by using these security solutions. However, the new hacking methods and tools that can detour or defeat these solutions have been emerging and even script kids using these methods and tools can easily hack the systems. In consequence, system has gone through various difficulties. So, Necessity of intruder trace-back technology is increased gradually. Trace-back technology is tracing back a malicious hacker to his real location. trace-back technology is largely divided into TCP connection trace-back and IP packet trace-back to trace spoofed IP of form denial-of-service attacks. TCP connection trace-back technology that autonomously traces back the real location of hacker who attacks system using stepping stone at real time. In this paper, We will describe watermark trace-back system using TCP hijacking technique to supplement difficult problem of connection maintenance happened at watermark insertion. Through proposed result, we may search attacker's real location which attempt attack through multiple connection by real time.

• Journal of Internet Computing and Services
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• v.9 no.6
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• pp.73-79
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• 2008

Nowadays, all over the world's banks use internet banking through various authentication methods. Although there are strong authentication methods using OTP (One Time Password), there still has vulnerability from sophisticated attacks such as MITM (Man In The Middle). This letter proposes signing-based authentication protocol that copes with attacks, such as MITB (Man In The Browser), and provides non-repudiation function. The protocol shows generic method to prevent the sophisticated attacks through connecting advantages from OTP and PKI (Public Key Infrastructure) certificate, and that can be deployed to various extended form in internet banking.