• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.4C
• /
• pp.581-593
• /
• 2004

The interest in wireless LAN security is on the increase owing to a role of high-speed wireless Internet infrastructure of wireless LAN. Wi-Fi has released WPA standard in order to overcome drawbacks of WEP algorithm that is security element of current IEEE 802.11-based wireless LAN system. Pairwise key management and group key management in a mixed-mode which supports both terminals running WPA and terminals running original WEP security are very complicate. In this paper, we analyze flaws in WPA authenticator key management state machine for key distribution and propose the countermeasures to overcome the analyzed problems. Additionally, WPA authenticator key management state machine to which the solutions are applied is described. The reconstructed WPA authenticator key management state machine helps the AP perform efficiently group key exchange and group key update in the mixed-mode.

• Convergence Security Journal
• /
• v.10 no.1
• /
• pp.9-17
• /
• 2010

Internet network routing system is used to prevent spread and distribution of malicious data traffic. The penetration of malicious code and the function of security blocking are performed on the same course of traffic pathway. The security architecture is the concept to distinguish the architecture from the group handling with the traffic on the structure of network which is performed with the function of penetration and security. The security architecture could be different from the criterion of its realm and function, which requires the development and the application of security mechanism for every architecture. For the establishment of security architecture it is needed to show what criterion of net work should be set up. This study is based on analysis of diagnostic weakness structure in the network security architecture and research the criterion for topology factor, security architecture structure map selection, and blocking location and disinfection net. It is shown to increase the effective rate blocking the virus with the proposed method in this paper rather than the traditional network architecture.

• Journal of Digital Contents Society
• /
• v.14 no.2
• /
• pp.263-274
• /
• 2013

As the numbers of Internet users and the growth of education market along with the generalization of distance study increase, e-Learning industry in China is growing rapidly more than 20% each year. However, domestic e-Learning industry for entry to the Chinese market is showing inadequate result even though its potential growth in China and their scale of industry is near about 3 trillion won. A type of this industry is combined with Information Technology (IT) and education industry and their complex factors need to be considered because of the country's education policy and ICT infrastructure. In addition to these factors, sometimes main agents can be the government or a private organization and they form different circumstances each other. Therefore, it is required to have an in-depth study of the entering the Chinese market based on an accurate analysis for Chinese education and culture. In this research, it will focus on the current state of e-Learning market in Korea and China after studying the e-Learning system through the existing reference research. Moreover, this research will propose a method of the entry for the Chinese e-Leaning market through a case study from domestic and foreign companies.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.42 no.3 s.303
• /
• pp.73-82
• /
• 2005

Recently, The wide range of the Internet applications and the related technology developments enabled the ease use of the digital multimedia contents (fixed images, movies, digital audios). However, due to the replay ability which the contents may be easily duplicated and not only the duplicates are capable of providing the same original quality. There are mainly the encipher techniques and the watermarking techniques which are studied and used as solutions for the above problem in order to protect the license holders' rights. To the protection of the IP(Intellectual Property) rights of the owner, digital watermarking is the technique that authenticates the legal copyrighter. This paper proposed the watermarking algorithms to watermark the 256 gray logo image and the color image by applying the wavelet transformation to the color stand-still images. The proposed algorithms conducted the watermark insertion at the LH frequency region among the wavelet transformation regions (LL, LH, HL, HH). The interleaving algorithms which applied in data communication was applied to the watermark. the amount of watermark increased which consequently caused the PSNR to decrease but this might provide the perseverance against the external attacks such as extraction, filtering, and crop.

• Journal of Digital Convergence
• /
• v.13 no.5
• /
• pp.21-29
• /
• 2015

The emergence of the internet causes the electronic trade of movies, music, software and other digital content products to be an eminent share of international commerce. The purpose of this study is to examine legal issues of electronic commerce chapters of the Korea US FTA and tasks of the digital contents industry. Results of the study show that several implications based on the industry are offered. The Korean government needs to do the following: settle of classification issue in digital contents, settle of customs issue in digital contents, settle of issue of non-discrimination principle in digital contents, settle of exclusion issue in audiovisual services, improve of global competitiveness, unify of export support system, establish of overseas expansion strategy in genre and regional contents, train of global experts and protect of intellectual property in digital contents.

• International journal of advanced smart convergence
• /
• v.4 no.2
• /
• pp.94-102
• /
• 2015

Optical camera communication (OCC) is an extension of Visible Light Communication. Different from traditional visible light communication, optical camera communications is an almost no additional cost technology by taking the advantage of build-in camera in devices. It was became a candidate for communication protocol for IoT. Camera module can be easy attached to IoT device, because it is small and flexible. Furthermore almost smartphone equip one or two camera for both back and font side with high quality and resolution. It can be utilized for receiving the data from LED or positioning. Actually, OCC combines illumination and communication. It can supply communication for special areas or environment where do not allow Radio frequency such as hospital, airplane etc. There are many concept and experiment be proposed. In this paper we proposed utilizing Android smart-phone camera for receiver and introduce new approach in modulation scheme for LED at transmitter. It also show how Manchester coding can be used encode bits while at the same time being successfully decoded by Android smart-phone camera. We introduce new data frame format for easy decoded and can be achieve high bit rate. This format can be easy to adapt to performance limit of Android operator or embedded system.

• Korean Journal of Social Welfare
• /
• v.68 no.3
• /
• pp.105-125
• /
• 2016

School absenteeism is considered one of the early predictors of school drop-out and serious delinquency or criminal behavior. The primary goal of the current study was to explore the protective and risk factors related to changing school absenteeism over time based on the ecological-systemic perspective. The data was derived from the Korean Children and Youth Panel Survey (KCYPS) using the 2011 and 2012 survey waves collected from 2,378 elementary school students. Using this data, Panel Fixed Effects Analysis was conducted. Major findings indicated that daily computer usage, parental abuse, school activity attendance, and school grades had an effect on students missing school days over time. Specifically, high levels of computer usage and parental abuse were related to increased school absenteeism, while high levels of school activity attendance and school grades were associated with decreased school absenteeism. These findings emphasized the importance of predictive intervention for children and suggested the need to construct a school absenteeism monitoring system in South Korea.

• Journal of Korea Society of Industrial Information Systems
• /
• v.22 no.4
• /
• pp.11-18
• /
• 2017

The Objective of this Study is to Prove the Effectiveness of a Smart Water Management(SWM) Technology. The SWM Technology can Reduce the Production Cost using Internet of Thing(IoT) Technology that Utilizes Remote Metering of Consumer's Water usage and Reduce the Leakage of Supply Facilities. The SWM Demonstration Model Installed a Remote Water Leakage Sensor, Smart Metering and Micro Multi Sensor in Water Supply Facility, and Provided Real-Time Monitoring of the Operation Status. Consumers can be Provided the usage of Tap Water and the Water Puality through a Smart Phone Application. At this Time, we Surveyed Whether Consumers save the Tap Water or Drinking Directly using the Tap Water usage Information. Also, this Study is to Verify the Degree of Improvement of Water Supply Rates and Drinking Water Rate, and to Decrease Consumer's Complaints, Operating Costs, and Water Consumption by the SWM Technology. It is also Established a SWM Model Combined with the IoT Sensor at Supply Facilities, operator monitoring system and explored recovery solution detected events. It means the upbringing of the domestic water industry by developing the related technologies and spreading the SWM to advanced levels.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.36 no.4
• /
• pp.245-254
• /
• 2018

Impact of tropospheric correction techniques on accuracy of the GPS (Global Positioning System) derived ellipsoidal heights has been experimentally assessed in this paper. To this end, 247 baselines were constructed from a total of 88 CORS (Continuously Operating Reference Stations) in Korea. The GPS measurements for seven days, acquired from the so-called integrated GNSS (Global Navigation Satellite Systems) data center via internet connection, have been processed by two baseline processing software packages with an application of the empirical models, such as Hopfield, modified Hopfield and Saastamoinen, and the estimation techniques based on the DD (Double-Differenced) measurements and the PPP (Precise Point Positioning) technique; hence a total number of the baseline processed and tested was 8,645. Accuracy and precision of the estimated heights from the various correction schemes were analyzed about baseline lengths and height differences of the testing baselines. Details of these results are summarized with a view to hopefully providing an overall guideline of a suitable selection of the modeling scheme with respect to processing conditions, such as the baseline length and the height differences.

• Journal of Hydrogen and New Energy
• /
• v.25 no.4
• /
• pp.393-404
• /
• 2014

Unmanned aerial vehicles (UAVs) have been applied to not only military missions like surveillance and reconnaissance but also commercial missions like meteorological observation, aerial photograph, communication relay, internet network build and disaster observation. Fuel cells make UAVs eco-friendly by using hydrogen. Proton exchange membrane fuel cells (PEMFCs) show low operation temperature, high efficiency, low noise and high energy density and those characterisitcs are well fitted with UAVs. Thus Fuel cell based UAVs have been actively developed in the world. Recently, fuel cell UAVs have started to develope for high altitude UAVs because target altitude of UAVs is expanded upto stratosphere altitude. Long endurance of UAVs is essential to improve effects of the missions. Improvement of UAV endurance time could be fulfilled by developing a hydrogen fuel storage system with high energy density and reducing the weight of UAVs. In this paper, research trend and analysis of fuel cell UAVs are introduced in terms of their altitude and endurance time and then the prospect of fuel cell UAVs are shown.