• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.12 no.1
• /
• pp.58-71
• /
• 2019

This paper proposes architecture of a cognitive radio engine platform and the allowable frequency channel reasoning method that enables acquisition of the allowable channels for the military tactical network environment. The current military tactical wireless communication system is increasing need to secure a supplementary radio frequency to ensure that multiple wireless networks for different military wireless devices coexist, so that tactical wireless communication between the same or different systems can be operated effectively. This paper presents the allowable frequency channel reasoning method based on cognitive radio engine for realizing DSA(Dynamic Spectrum Access) as an optimal available frequency channel. To this end, a case-based allowable frequency channel reasoning method for cognitive radio devices is proposed through modeling of primary user's traffic status and calculation of channel occupancy probability. Also through the simulation of the performance analysis, changing rate of collision probability between the primary users' occupancy channel and the available channel acquisition information that can be used by the cognitive radio device was analysed.

• Journal of the Society of Disaster Information
• /
• v.18 no.3
• /
• pp.487-494
• /
• 2022

Purpose: This study proposes a Metaverse-based police education and training model that can efficiently improve the performance of various police activities according to changes in the environment of the times. Method: The structure of this system can generate Avatar Controller expressed using HMD and haptic technology, access the Network Interface, and educate and train individually or on a team basis through the command control module, education and training content module, and analysis module. Result: In the proposed model of this study, the command and control module was incorporated into individual or team-based education and training, enabling organic collaborative training among team members by monitoring the overall situation of terrorism or crime in real time. Conclusion: Metaverses-based individual or team-based police education and training can provide a more efficient and safe education and training environment based on immersion, interaction, and rapid judgment in various situations.

• Journal of Korea Society of Industrial Information Systems
• /
• v.15 no.4
• /
• pp.7-15
• /
• 2010

This study proposes a rad o resource management scheme to maximize the performance of the LTE(Long Term Evolution) uplink, using SC-FDMA(Single Carrier-Frequency Division Multiple Access). Rather than the single-cell SC-FDMA system the existing studies are mainly concerning, this study focuses on multi-cell system which needs considering the interaction among cells. Radio resource management is divided into two phases, planning and operation phases. The former is for the master eNB(e-NodeB) to allocate RBs(radio bearer) to eNB, the latter for eNB to assign RBs to the mobiles in the cell. For each phase, an optimization model and greedy algorithm are proposed. Optimization models aim to maximize the system performance while satisfying the constraints for both QoS and RB continuity. The greedy algorithms, like generic ones, move from a solution to a neighboring one having the best objective value among neighboring ones. From the numerous numerical experiments, the performance and characteristics of the algorithms are analyzed. This study is expected to play a volunteering role in radio resource management for the multi-cell SC-FDMA system.

• Convergence Security Journal
• /
• v.23 no.1
• /
• pp.19-25
• /
• 2023

The current network environment provides a real-time interactive service from an initial one-way information prov ision service. Depending on the form of web-based information sharing, it is possible to provide various knowledge a nd services between users. However, in this web-based real-time information sharing environment, cases of damage by illegal attackers who exploit network vulnerabilities are increasing rapidly. In particular, for attackers who attempt a phishing attack, a link to the corresponding web page is induced after actively generating a forged web page to a user who needs a specific web page service. In this paper, we analyze whether users directly and actively forge a sp ecific site rather than a passive server-based detection method. For this purpose, it is possible to prevent leakage of important personal information of general users by detecting a disguised webpage of an attacker who induces illegal webpage access using traceback information

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.3
• /
• pp.221-237
• /
• 2023

This study was conducted as part of a phased study aimed at closely examining the mutual ecosystem between creators and viewers through paying attention to the personal media environment that is in the center of rapid changes in the media industry and particularly exploring the areas of activity of the single-person or minority media creators who lead the mobile media environment that could be accessed, viewed and produced anywhere. In particular, this study aimed to not only pay attention to the situation in which the potential to expand professional YouTuber areas encounters the changing desire and demand of content service users who continue to become more evolved as time passes, but also examine the influence of the reputation of professional YouTubers on users' loyalty and subscription intention, examine the moderating effect of sincerity on the relationship between YouTubers and users, and demonstrate such relationship formation process based on concrete data. In the conclusion section, implications that can be drawn from the study results and suggestions for further studies in the future were proposed.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.4D
• /
• pp.443-450
• /
• 2009

Uninterrupted facility - since there is a close relationship between traffic volume, speed and density -, when a ramp traffic flow merges into the main line, will change the traffic speed or density, and the corresponding correlational model equation will be changed. Thus, this study, using time and space-series traffic data on areas under the influence of such a merging, identified sections which changed the correlation between speed and density variables, and examined such changes. As a result, the upstream and merging sections showed the "Underwood"-shaped exponent, and the downstream after passing the merging section showed a straight line "Greenshields" model. The downstream section which changed the correlation between speed and density showed a gradual downstream movement phenomenon within 100 m-500 m from the end of the third lane linking with the ramp, as the traffic approached the inner lanes. Also, the upstream section, merging section, and downstream section involving a change showed heterogeneous traffic flows which, in the speed-density model, have a statistically different free flow speed (constant) and a different ratio of free flow speed to jam density (gradient).

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.39B no.4
• /
• pp.207-215
• /
• 2014

Password based authentication systems are most widely used for user convenience in web services. However such authentication systems are known to be vulnerable to various attacks such as password guessing attack, dictionary attack and key logging attack. Besides, many of the web systems just provide user authentication in a one-way fashion such that web clients cannot verify the authenticity of the web server to which they set access and give passwords. Therefore, it is too difficult to protect against DNS spoofing, phishing and pharming attacks. To cope with the security threats, web system adopts several enhanced schemes utilizing one time password (OTP) or long and strong passwords including special characters. However there are still practical issues. Users are required to buy OTP devices and strong passwords are less convenient to use. Above all, one-way authentication schemes generate several vulnerabilities. To solve the problems, we propose a multi-channel, multi-factor authentication scheme by utilizing QR-Code. The proposed scheme supports both user and server authentications mutually, thereby protecting against attacks such as phishing and pharming attacks. Also, the proposed scheme makes use of a portable smart device as a OTP generator so that the system is convenient and secure against traditional password attacks.

• Archives of design research
• /
• v.13 no.3
• /
• pp.211-220
• /
• 2000

Cultural contact, which means a current that an influential culture diffuses to another, represents the penetration of the one to the other in a negative respect and'mixture'or 'fusion'of them in an affirmative respect. Fusion of cultures was not easy to take place in the past when nationalism and ultranationalism suppressed it ideologically, inconvenient transportation and communications were obstacles to it, and most of countries were under the influences of folk religions. Today, however, mutually heterogeneous cultures can be shared by a lot of things such as collapse of a view of nation resulted from globalization, breakdown of regional characteristics, abolition of trade barriers, freedom of communications and realtime information network. Those have rendered fusion possible. Fusion in this modern consuming society is extending much faster and more extensively than at any time in the past. In addition, more and more cultural elements seem to collide and compromise with one another in the name of fusion, not relaxing the bridle of fusion, from the present situations that preference in consumption becomes subdivided and a variety of individuality is strongly attempted to seek for, This study is on the subject of the properties of'Fusion', one of new styles in a mass culture, especially focused on sociologic cultural phenomena. Furthermore, it is expected to look for a fusion in interior design which expresses sociologic cultural phenomena most in a field of design, to examine it theoretically, and to prospect a future trend of fusion design based on investigation of the latest prevailing trend.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.2 s.344
• /
• pp.49-55
• /
• 2006

This paper describe the most advanced database management system for the mobile number portability(MNP) in the world The database management system can process the procedure of porting_out and porting_in in 30 minutes and it is the shortest time in the world. The MNP DB management system consists of two functional blocks, one is for the call processing system and the other is for the management of subscriber of MNP. The hardware and processing algorithm are presented in this paper. The DB for call processing is located at each mobile operator and be called local number portability database (L-NPDB). The DB for the management of subscriber of MNP consist of L-NPDB and master database which is located at the Korea telecommunications operators association(KTOA). The hardware database system for MNP consists of the interconnection system of master-NPCDB (NP customer database, M-NPCDB), local-NPCDB, M-NPDB and L-NPDB. The master database is interconnected to the local database through dedicated line and can process any MNP service in real time. The presented MNP structure in this paper has been implemented in Korea and became the most effective and advanced DB management system for MNP in the world.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.37 no.1
• /
• pp.44-51
• /
• 2000

We have analyzed optical matched filters considering the third order signals in the optical code division multiple access (CDMA) system based on optical series coupler access encoder (SCAE) and series coupler access decoder (SCAD). In previous studies, the performance evaluation of the optical CDMA system using SCAE and SCAD was not sufficiently accurate because they analyzed system performance only considering the first order signals. Since optical SCAE and SCAD intrinsically have high order signals of various patterns as the number of coupler increases, they change auto- and cross-correlation intensities. Thus, it is necessary to investigate properties of the third order signals so that we may analyze the exact performance of system. In this paper, we mathematically interpret the optical signals up to the third order, and analyzed the effects of th third order signals on auto- and cross-correlation intensities. In result, as ${\alpha}$(coupling coefficient) value increases, the intensity of the third order signals increases. It is found that the peak to side-lobe ratio considering the third order signals is degraded by 3.75 dB at N(coupler number)=5 and ${\alpha}$=0.5. Also if threshold value in receiver is set by main-lobe peak of the first order signals, it is found that the number of users in an optical CDMA system is limited because the intensity peak of side-lobes is raised by the third order signals.