• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.5B
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• pp.475-488
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• 2003

To prevent performance degradation of TCP due to packet losses in the smooth handoff by the route optimization extension of Mobile IP protocol, a buffering of packets at a base station is needed. A buffering of packets at a base station recovers those packets dropped during handoff by forwarding buffered packets at the old base station to the mobile user. But, when the mobile user moves to a congested base station in a new foreign subnetwork, those buffered packets forwarded by the old base station are dropped and TCP transmission performance of a mobile user in the congested base station degrades due to increased congestion by those forwarded burst packets. In this paper, considering the general case that a mobile user moves to a congested base station, we analyze the influence of packet buffering on TCP performance according to handoff arrival distribution for Drop-tail and RED (Random Early Detection) buffer management schemes. Simulation results show that RED scheme can reduce the congestion increased by those forwarded burst packets comparing Drop-Tail, but RED scheme cannot avoid Global Synchronization due to forwarded burst packets by the old base station and new buffer management scheme to avoid it is needed in Mobile IP based networks.

• Journal of the Korea Convergence Society
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• v.9 no.4
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• pp.99-110
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• 2018

The data were collected from 171 physiologic malodor patients diagnosed in KUMC halitosis control clinic between 2008 and 2016. We selected 11 independent variables and 3 dependent variables, then planned to extract some convergent common factors affecting their physiologic malodor. We thought that those extracted convergent common factors could be utilized when preparing the contents of oral malodor preventive program. We used multiple regression analysis and path analysis method, for the analysis of influence of 11 independent factors to three salivary dependent factors(resting salivary flow rate, salivary buffering capacity, salivary precipitation rate). We have presented the physiologic malodor patients' chracteristics by descriptive statistical analysis, and also statistically analysed convergent common factors influencing directly or indirectly to their three dependent factors. We could reason that the sex, the character, the intake habit of breakfast, and the regular food intake habit could affect resting salivary flow rate, salivary buffering capacity and salivary precipitation rate.

• Journal of the Korean Institute of Landscape Architecture
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• v.29 no.6
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• pp.37-49
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• 2002

The objective of this research was an investigation of the important green spaces in Daegu and to present the basic frame of green network in Daegu. Present the condition of the significant green spaces is as follows: In the 3km radius of the city center, the isolation and discontinuation of the green spaces was extensive, caused by crowding of houses and funeral parlours. Consequently, the isolation relaxation which leads to the additional creation of the green spaces and a buffering plan were demanded. In the transfer area of a 3∼6km radius, which is located between the city center's congested area and the suburb green spaces, the significant green spaces had high connection and buffering characteristic, but in the northwest and the south, serious discontinuation appeared between the suburb green spaces and the city conte green spaces. In the 6∼9km radius, the suburb important green spaces accomplished the function which extended the back core green spaces to the city center area. But creation of buffering green spaces was necessary in part because of proximity to the resident area. The results suggest a connection between green spaces on the base of the distribution of the important green spaces, were as follows: In the 3km radius, irregular direction lines appeared while a schedule one direction line appeared in 3∼6km and 6∼9km radius. The discontinued parts of the green network were caused by industrial complexes, house crowding, and cultivation areas. Consequently, reservation and creation plans of green spaces in response to this were demanded. Through the additional creation of green spaces in the discontinued parts, the basic frame of green network in Daegu was the radiation annular form. And it was suitable to activate the parks and the general green spaces.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1769-1778
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• 2009

Due to the industrialization and urbanization, the transport of hazardous materials increases, which rises possibilities in occurring prospective accidents in terms of hazardous material transport as well. This study applied the model developed from the previous research to analyze the scale of damage areas from the accidents related to hazardous material accidents, as well as suggested a method to measure automatically the scale of accident including casualties and environmental damage based on the guideline which suggests the quantities of hazardous materials exposed from an accident and was defined in the study of standardization for hazardous material classification. A buffering analysis technique of Geographic Information System (GIS) was applied for that. To apply the model which evaluates the scale of population and exposure to environment on each link, rail network, zones, rail accident data, rail freight trips, and locations of rivers etc were complied as a database for GIS analysis. In conclusion, a method to measure damage areas by the types of hazardous materials was introduced using a Clip and a Special Join technique for overlay analysis.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.12
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• pp.849-854
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• 2013

In this paper, a system technology-based algorithms and visualization is proposed to show a space data. Also the proposed system provides analysis function with combination of usual map and automatic document generation function to give a useful information for making an important decision based on spatial distributed data. In the proposed method, we employ the heat map analysis to present a suitable color distribution for 2 dimensional map data. The buffering analysis method is also used to define the spatial data access. By using the proposed system, spatial information in a variety of distribution will be easy to identify. Also, if we make a use of automatic document generation function in the proposed algorithm, a lot of time and cost savings are expected to make electronic document which representation of spatial information is required.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.12
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• pp.1045-1053
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• 2013

In this paper, we propose a new power-saving mechanism (PSM) for Long-Term Evolution (LTE) systems by considering a round-trip delay between a user equipment (UE) and its correspondence node. The proposed PSM changes the order of the operational procedures of the legacy LTE PSM by taking the traffic arrival pattern suffering the round-trip delay into account. After modeling the round-trip delay, we numerically analyze the proposed PSM with respect to energy consumption and buffering delay. Then, we characterize these performances by employing a simple energy-delay tradeoff (EDT) curve according to the operational parameters. The resulting EDT curve clearly shows that the proposed PSM outperforms the legacy LTE PSM in terms of both the energy consumption and buffering delay.

• The Journal of the Korea Contents Association
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• v.1 no.1
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• pp.130-136
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• 2001

Real-time applications like VoIP in mobile networks need smooth handovers in order to minimize or eliminate packet loss as a mobile host(MH) transitions between network links. In this paper, we design a new variable buffering mechanism for IPv6 by which an MH can request that the router on its current subnet buffers pad(eta on its behalf while the MH completes registration procedures with the router of a new subnet. Performance results show that our proposed queueing scheme with a variable space allocation is quite appropriate for mobile internet environment in terms of the packet loss rate.

• Journal of the Korea Safety Management & Science
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• v.12 no.1
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• pp.35-42
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• 2010

Due to the industrialization and urbanization, the transport of hazardous materials increases, which rises possibilities in occurring prospective accidents in terms of hazardous material transport as well. This study applied the model developed from the previous research to analyze the scale of damage areas from the accidents related to hazardous material accidents, as well as suggested a method to measure automatically the scale of accident including casualties and environmental damage based on the guideline which suggests the quantities of hazardous materials exposed from an accident and was defined in the study of standardization for hazardous material classification. A buffering analysis technique of Geographic Information System (GIS) was applied for that. To apply the model which evaluates the scale of population and exposure to environment on each link, rail network, zones, rail accident data, rail freight trips, and locations of rivers etc were complied as a database for GIS analysis. In conclusion, a method to measure damage areas by the types of hazardous materials was introduced using a Clip and a Special Join technique for overlay analysis.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.4
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• pp.65-72
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• 2009

In this paper, we propose a proxy-based fast handover scheme to improve a performance in the mobile WiMAX network using PMIPv6 for supporting the network-layer mobility. In our proposed scheme, we define three link-layer messages and one network-layer message to reduce the handover latency, and propose a buffering mechanism to minimize packet loss and solve out-of-sequence problem. A performance evaluation indicates that the proposed scheme works more efficiently than PMIPv6 in terms of the handover latency and packet loss.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6A
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• pp.832-844
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• 1999

In this paper, we analyzed mobile-IP protocol of IETF, and propose new method to improve performance in handover environments. In proposed method, cache agent manages mobility binding information for mobile host. Thus, effective support of mobility is possible. Also, when handover occurs, mobile host recognizes change of foreign agent, and transmits registration message to new foreign agent. However, during registration time, data packet loss is occurs in old foreign agent. Thus, we prevent data loss by using data packet buffering and forwarding in old foreign agent.According to simulation results for data packet transmission performance in the case of handover occurring, proposed method has better performance than previous method in the view of transmission delay and throughput. Especially, if handover occurs very often, data buffering and forwarding method in foreign agent could guarantee better performance.