• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.16 no.6
• /
• pp.153-158
• /
• 2016

Broadcasting in multi-hop wireless sensor networks is a basic operation that supports many applications such as route search, setting up addresses and sending messages from the sink to sensor nodes. The broadcasting using flooding causes problems that can be mentioned as a broadcasting storm such as redundancy, contention and collision. A variety of broadcasting schemes using wireless sensor networks have been proposed to achieve superior performance rather than simple flooding scheme. Broadcasting algorithms in wireless sensor networks can be classified into six subcategories: flooding scheme, probabilistic scheme, counter-based scheme, distance-based scheme, location-based schemes, and neighbor knowledge-based scheme. This study analyzes a simple flooding scheme, probabilistic scheme, counter-based scheme, distance-based scheme, and neighbor knowledge-based scheme, and compares the performance and efficiency of each scheme through network simulation.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.11B
• /
• pp.673-684
• /
• 2007

In this paper, we introduce an FARNS (Flooding algorithm with Adaptive Retransmission Nodes Selection). It is an efficient cross layer-based flooding technique to solve broadcast storm problem that is produced by simple flooding of nodes in wireless sensor network. FARNS can decrease waste of unnecessary energy by preventing retransmission action of whole network node by deciding retransmission candidate nodes that are selected by identification in MAC and distance with neighborhood node through received signal strength information in PHY. In simulation part, we show the results that FARNS has excellent performance than the other flooding schemes in terms of broadcast forwarding ratio, broadcast delivery ratio, number of redundancy packets and overhead. And FARNS can adjust of node ratio for retransmission operation, it can solve broadcast storm problem as well as meet the requirements of various network environments.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.10 no.5
• /
• pp.149-158
• /
• 2010

Recent rainfall patterns in Korea show that both of the total amount of rainfall and the total number of heavy rain days have been increased. Therefore, the damage resulted from flood disaster has been dramatically increased in Korea. The purpose of the present study is to analyze flooding in an urban area using SWMM linked with FLUMEN. The study area is Suyeong-Mangmi lowland area, Busan, Korea. Suyeong-Mangmi lowland area have been a flooding hazard zone since 1995. The last flooding cases of this area occurred on July 7th and 16th, 2009, and the later flooding case was analyzed in this study. The first step of computation is calculating flow through storm sewers using the urban runoff simulation model of SWMM. The flooding hydrographs are used in the inundation analysis model of FLUMEN. The results of inundation analysis were compared with the real flooding situation of the study area. The real maximum inundation depth was guessed by 1.0 m or more on July 16th. The computation yields the maximum inundation depth of 1.2 m and the result was somewhat overestimated. The errors may be resulted from the runoff simulation and incapability of simulation using FLUMEN for flow into buildings. The models and procedures used in this study can be applied to analysis of flooding resulted from severe rainfall and insufficiency of drainage capacity.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.27 no.6
• /
• pp.723-731
• /
• 2009

Recently, it has been strangely increasing rainfall and rainfall meter by global warming. so flood damage is being increase. It has happened there are so many damaged by influence by backwater of dam. However, the alleviative solutions of flood damages are focused on the lower river basin where the density of population is higher than upper river basin. This research proceeds based on design and build 3D topography model and reflects the topographical factors of upper river basin. It also simulated the circumstances of flooding by investigation of factors of outflow, hence, as a result, we would find out the vulnerable area for flooding and scale of damages effectively. This research suggests the solution and method of flooding for vulnerable area of the flooding to reduce the damages by predicting flooding. Thus, the suggestion may support to make a decision efficiently to prevent the damage of flooding.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.05b
• /
• pp.159-162
• /
• 2005

Urban flooding is usually caused by the surcharge of storm sewers. For that reason, domestic studies about urban flooding are concentrated on the simulation of urban drainage system. However these approaches that find the pipes which have insufficient drainage capacity are very approximate and unreasonable ways. In this study, an accurate mathematical modeling is developed to analyze the impacts of an urban inundation for both flood prevention and flood-loss reduction planning and it is verified by using the simulation of July 2001 flooding in Seoul. The result of this study can be used to construct fundamental data for a flood control plan and establish a urban flood forecasting/warning system.

• Journal of Fisheries and Marine Sciences Education
• /
• v.29 no.1
• /
• pp.286-296
• /
• 2017

This paper conducted a simulation to research the motion of a vessel, which had the flooding accident in the Bering Sea in 2014, thereby being flooded and un-steerable. As the wind condition was very harsh, the vessel was modeled as 3D including large upper deck structures and the Fujiwara's method was used for an estimation of the effect of wind forces and moments acting on ship. In the case of wave influence, AQWA-Drift that enables considering the effects of drift force and AQWA-Naut that enables considering the effects of green water were mainly used. Basically, loading and flooding condition were equal to the accident condition but half-drained condition was also used to consider drain ability. Furthermore, both 6 DOF and 5 DOF option that Yaw motion is fixed, were utilized to compare the steerable and un-steerable condition. As a result, the author found out that what roll angle triggers green water, how often it happens, and how the vessel moves on the stormy weather condition.

• Journal of the Korea Society for Simulation
• /
• v.15 no.1
• /
• pp.69-75
• /
• 2006

P2P services occupy more then 50% of the internet traffics. A huge number of query packets are generated since pure P2P based models rely on message flooding for their query mechanisms. In this study, the numbers of query messages generated in the pure P2P and hybrid P2P model are analyzed. The results show that hybrid P2P models also could suffer from message flooding. To reduce the message flooding, this study proposes an interest based clustering mechanism for hybrid P2P services. By applying this clustering algorithm, it could reduce 99.998% of the message flooding. The proposed algorithm also reduces the cost of the joining operations by storing previous supernodes.

• Geosystem Engineering
• /
• v.21 no.6
• /
• pp.335-343
• /
• 2018

Alkali-surfactant polymer flooding has become an important technique to improve oil recovery following the development of oil fields while the function of emulsification in enhanced oil recovery is rarely considered in the existing mathematical model for numerical simulation. In this paper, the mechanism of improving the recovery of the emulsification was analyzed in ASP flooding, and a relatively perfect mathematical model with deep filtration-theory was established, in which oil-water volume equation, saturation equation, viscosity equation, and permeability reduction equation are included. The new model is used to simulate the actual block of an oil field; the simulated results of the new model and an old model without considering the emulsification are compared with the actual well history. It is found that new model which is easy to be realized in numerical simulation has a high precision fitting, and the effect of adding oil and decreasing water is obvious. The sensitivity of emulsification was analyzed, and the results show that the water reducing funnel becomes wider and the rate of water cut decreases rapidly with the increase of emulsifying capacity, and then the rate of recovery slows down. The effect of increasing oil and decreasing water is better, and the degree of recovery increases. The emulsification of the ASP flooding is maintained at a moderate level, which corresponds to ${\Phi}=0.2$ in the new model, and the emulsification is applied to realize the general mathematical quantitative description, so as to better guide the oilfield development.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1568-1570
• /
• 2005

The internet is already a part of life. It is very convenient and people can do almost everything with internet that should be done in real life. Along with the increase of the number of internet user, various network attacks through the internet have been increased as well. Also, Large-scale network attacks are a cause great concern for the computer security communication. These network attack becomes biggest threat could be down utility of network availability. Most of the techniques to detect and analyze abnormal traffic are statistic technique using mathematical modeling. It is difficult accurately to analyze abnormal traffic attack using mathematical modeling, but network simulation technique is possible to analyze and simulate under various network simulation environment with attack scenarios. This paper performs modeling and simulation under virtual network environment including $NGSS^{1}$ system to analyze abnormal traffic-flooding attack.

• The KIPS Transactions:PartC
• /
• v.16C no.2
• /
• pp.209-216
• /
• 2009

In the wireless sensor network, flooding is required for the dissemination of queries and event announcements. The simple flooding causes the implosion and the overlap problems, so the simple flooding may result in the reduced network lifetime. Therefore, in this paper, we propose the flooding overlay structure (FOS) so that the overhead caused by flooding can be reduced. We propose two variants of FOS mechanisms, the centralized FOS (CFOS) and the distributed FOS (DFOS). In CFOS, the sink collects the network topology information and selects forwarding nodes based on that information. On the other hand, DFOS allows each sensor node to decide whether to act as a forwarding node or not based on its local information. For the performance evaluation of our proposed mechanisms, we carry out NS-2 based simulations and compare ours with the simple flooding and the gossiping. The simulation results indicate that the proposed FOS mechanisms outperform the simple flooding in terms of the network lifetime and the gossiping in terms of the data delivery ratio.