• Tunnel and Underground Space
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• v.13 no.5
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• pp.344-352
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• 2003

The procedures to correct sampling biases for discontinuity data obtained from 1D survey line(borehole or scanline) is addressed. The Probability of intersection between the survey line and a circular discontinuity is considered, and a correction far orientation bias is developed assuming discontinuities as equivalent circular disks. The correction incorporates the effect of the angle between the direction of survey line and each discontinuity plane belonging to the discontinuity cluster, size of each discontinuity and length of the survey line. A procedure is provided to estimate unbiased discontinuity spacing parameters using the discontinuity spacing data based on the measurements carried out on a finite length of the survey line.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.37-41
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• 2018

As individuals generate and share various content anytime and anywhere, new networking architectures, such as content-centric networking (CCN) using the content name as a packet identifier, have been in the spotlight recently. However, the current CCN hardly takes into account node mobility problems, especially the mobility of content sources. The movement of content sources causes long delivery latency and long service disruptions. To solve that, the tunneling-based redirection scheme was proposed. However, the tunneling-based scheme requires a location-update procedure whenever the network changes, which creates many control messages and causes long latency. So, this paper presents hierarchical mobility management of mobile CCN to reduce the number of control messages and handoff latency. Performance evaluation shows that the proposed scheme can provide low control overhead, which results in network scalability.

• Tunnel and Underground Space
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• v.27 no.6
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• pp.357-365
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• 2017

The mine subsidence prevention technology has been promoted based on the field test for design, construction, automation measurement and monitoring optimized for investigation, design and mine-filling efficiency customized in Korean mining environment. Based on the R&D roadmap ('07~'16) of the 1st and 2nd stage, mine reclamation technology development has been focused on developing method of evaluating subsidence stability, development of filling material and optimum filling technology, and development of measuring instrument. In the future, in order to systematic management for the subsidence risk areas, we intend to enhance technological capabilities and strengthen the technological infrastructure for business promotion in parallel with the discovery and introduction of new technology to prevent subsidence in the 4th Industrial Revolution era.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.14-18
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• 2019

The conductivity of a semiconductor is primarily determined by the carriers. To achieve higher conductivity, the number of carriers should be high, and an energy trap level is created so that the carriers can cross the forbidden zone with low energy. Carriers have a crystalline binding structure, and interfacial mismatching tends to make them less conductive. In general, high-concentration doping is typically used to increase mobility. However, higher conductivity is also observed in non-orthogonal conjugation structures. In this study, the phenomena of higher conductivity and higher mobility were observed with space charge limiting current due to tunneling phenomena, which are different from trapping phenomena. In an atypical structure, the number of carriers is low, the resistance is high, and the on/off characteristics of capacitances are improved, thus increasing the mobility. ZTO thin film improved the on/off characteristics of capacitances after heat treating at $150^{\circ}C$. In charging and discharging tests, there was a time difference in the charge and discharging shapes, there was no distinction between n and p type, and the bonding structure was amorphous, such as in the depletion layer. The amorphous bonding structure can be seen as a potential barrier, which is also a source of space charge limiting current and causes conduction as a result of tunneling. Thus, increased mobility was observed in the non-structured configuration, and the conductivity increased despite the reduction of carriers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6B
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• pp.420-429
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• 2008

Currently, IEEE 802.11 Network could not support optimized tunneling scheme and buffering scheme based on movement detection to reduce multimedia data packet loss when an MN move from current subnet to new subnet during handover. It is because IEEE 802.11 did not transfer information of movement detection to AP. In this paper, we proposed new fast handover scheme by using advanced access point and optimized snoop protocol for network based Proxy Mobile IPv6 in IEEE 802.11 Networks. During handover, the proposed scheme reduces both the multimedia data packet loss rate and the packet reordering problems without changing MN's mobility stack in IEEE 802.11 Networks.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.2
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• pp.87-98
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• 2012

In recent years, there are many data and multimedia services that are supported by WiFi-enabled mobile devices. As a result, the demand for the ability to connect to the Internet anywhere is rapidly increasing and network infrastructure is becoming increasingly important. The design of cost-efficient network mobility (NEMO) protocol is intended to reduce the demand for limited wired/wireless network bandwidth at the signaling of mobility support and packet delivery operations. In this paper, we propose a cost-effective inter-LMA domain mobility management scheme which provides fast handover with multicasting support in NEMO environments. And our Fast PR-NEMO scheme is compared with N-PMIPv6, rNEMO, and PR-NEMO. In conclusion, our proposed scheme shows the best performance in terms of location updating cost, and packet tunneling cost.

• Journal of Internet Computing and Services
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• v.9 no.5
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• pp.175-183
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• 2008

Wi-Fi defines the procedure to search an AP, authenticate both station and AP, and associate the new BSS or ESS which enables the link layer handoff. One of the problems for hotspot service of Wi-Fi is "passing-object", Wi-Fi describes the messages exchanges between two neighboring APs in BSS or ESS. If the station passes through the neighboring APs before completing link-layer handoff, the path where the tunneled packets should be sent is lost. In this paper, we propose to integrate the positioning entity in a service domain to keep track the high-speed movement.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.7
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• pp.1257-1262
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• 2001

In recent years there has been a lot of interest in carrying IP over WDM networks in an efficient manner. The benefits here include larger bandwidth capacities, better network scalability, and more efficient operation. W based approach, termed "lambda-labeling" is presented for direct If over WDM integration. In this paper, we study on architecture approach method consider of optical Internet evolution that based on MPLamdaS conception of IETF. Label stack conception collect electronic LSP of optical LSP. This paper is proposed method of co-operation between MPLS domain and MPLambdaS domain. Additionally, proposed architecture of Edge Optical LSR.tical LSR.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.5
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• pp.219-227
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• 2012

This paper describes the design and implementation of an efficient image security system for CCTV using the analysis technique of color informations. In conventional approaches, the compression and encryption techniques are mainly used for reducing the data size of the original images while the analysis technique of color information is first proposed, which eliminates the overlapping part of the original image data in our approach. In addition, security-enhanced CCTV image security system is presented using SSL/VPN tunneling technique. When we use the method proposed in this paper, an efficient image processing is enable for a mount of information, and also security problem is enhanced. Through the implementation results, the proposed method showed that the original image information are dramatically reduced.

• Journal of the Korea Society of Computer and Information
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• v.8 no.4
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• pp.138-147
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• 2003

There are some problems of current internet protocols to support the mobility of terminal in wireless environments. The mobile IP has come out to solve these problems, but there exists some problems like triangle routing, the need of each host's home address and the management of tunneling. Also. real-time multimedia traffics require fast hand-off, low latency and the utilization ratio of high bandwidth. SIP can support the mobility of wireless terminal and is widely accepted as the protocol which can support multimedia service and call setup in next generation network. In this paper, the framework of SIP system will be designed and implemented to support the mobility of wireless terminal by using JAIN API which follow the standards of next generation network and this system matches the standards of next generation network.