• Journal of the Korea Society of Computer and Information
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• v.11 no.5 s.43
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• pp.165-173
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• 2006

Network Mobility Basic Support protocol enables mobile network to change their point of attachment to the Internet, but causes some problems such as suboptimal muting and multiple encapsulations. The proposed scheme, combining Prefix Delegation protocol with HMIPv6 concept can provide more effective route optimization and reduce the amount of packet losses and the burden of location registration for handoff. It also uses hierarchical mobile network prefix (HMNP) assignment and provides tree-based routing mechanism to allocate the location address of mobile network nodes (MNNs) and support micro-mobility. In this scheme, Mobility Management Router (MMR) not only maintains the binding informations for all MNNs in nested mobile networks, but also supports binding procedures to reduce the volume of handoff signals oyer the mobile network. The performance is evaluated using NS-2.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.8
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• pp.1505-1510
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• 2008

In large-scale wireless sensor networks, the deployed nodes cannot be replaced or recharged after first deployment. Also, dead nodes maγ lead to the partition of whole networks. While performing data dissemination under a battery power constraint, energy efficiency is a key design factor of routing protocol. As a solution for the efficient data dissemination, in this paper, we propose a protocol namely Hierarchical Data Dissemination (HDD) which provides scalable and efficient data delivery to multiple sources and mobile sinks. HDD uses the facts that sink nodes are central gathering Points and source-centric data forwarding paths are constructed and it is maintained with two-tier communications. The performance of HDD is compared with TTDD about the energy consumption, data delivery time and data success ration. The extensive simulation results show that HDD Routing Protocol outperforms TIDD by more than $1.5{\sim}3times$ on energy consumption.

• Journal of the Korea Society of Computer and Information
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• v.10 no.5 s.37
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• pp.227-236
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• 2005

Hierarchical Prefix Delegation (HPD) protocol refers to a type of solution to problems inherent in non-optimal routing which occurs with Network Mobility (NEMO) basic solution. However, because HPD cannot improve the micro-mobility Problems, Problem surfaces each time Mobile Network Node (MNN) changes the attachment point; as happens also in a Mobile IPv6 (MIPv6) protocol in sen야ng Binding Update (BU) messages to Home Agent (HA) / Correspondent Nodes(CNs) By applying Hierarchical Mobile IPv6 protocol concept to HPD, this study Proposes an algorithm for effectively handling micro-mobility problems which occur with HPD in a nested NEMO environment. By sending BU only to nearby Mobility Anchor Point(MAP) during MNN location change within a MAP's domain, the proposed protocol will alleviate service disruption delays and signaling loads during the handover process, overcoming the limitations of HPD.

• Journal of the Korea Society of Computer and Information
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• v.11 no.1 s.39
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• pp.147-155
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• 2006

Hierarchical Prefix Delegation (HPD) protocol refers to a type of solution to problems inherent in non-optimal routing which occurs with Network Mobility (NEMO) basic solution. However, because HPD cannot improve the micro-mobility problems, problem surfaces each time Mobile Network Node (MNN) changes the attachment point; as happens also in a Mobile IPv6 (MIPv6) protocol in sending Binding Update (BU) messages to Home Agent (HA) / Correspondent Nodes(CNs). By applying Hierarchical Mobile IPv6 protocol concept to HPD, this study proposes an algorithm for effectively handling micro-mobility problems which occur with HPD in a nested NEMO environment. By sending BU only to nearby Mobility Anchor Point(MAP) during MNN location change within a MAP's domain, the proposed protocol will alleviate service disruption delays and signaling loads during the handover process, overcoming the limitations of HPD.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.3
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• pp.166-171
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• 2023

Efficient energy management is a very important factor in sensor networks with limited resources, and cluster techniques have been studied a lot in this respect. However, a problem may occur in which energy use of the cluster header is concentrated, and when the cluster header is not evenly distributed over the entire area but concentrated in a specific area, the transmission distance of the cluster members may be large or very uneven. The transmission distance can be directly related to the problem of energy consumption. Since the energy of a specific node is quickly exhausted, the lifetime of the sensor network is shortened, and the efficiency of the entire sensor network is reduced. Thus, balanced energy consumption of sensor nodes is a very important research task. In this study, factors for balanced energy consumption by cluster headers and sensor nodes are analyzed, and a balancing distribution clustering method in which cluster headers are balanced distributed throughout the sensor network is proposed. The proposed cluster method uses multi-hop routing to reduce energy consumption of sensor nodes due to long-distance transmission. Existing multi-hop cluster studies sets up a multi-hop cluster path through a two-step process of cluster setup and routing path setup, whereas the proposed method establishes a hierarchical cluster routing path in the process of selecting cluster headers to minimize the overhead of control messages.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11a
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• pp.169-172
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• 2003

최근에 대규모 병렬컴퓨터의 새로운 위상으로 HHN(m;n,h) 그래프가 제안되었다. HHN(m;n,h) 그래프는 하이퍼큐브에 기반한 계층적인 상호 연결망이며, 노드개수가 유사한 하이퍼큐브보다 작은 노드 분지수와 작은 링크의 수를 가지고 있기 때문에 대규모 병렬 컴퓨터를 구성하는 상호 연결망이지만, 심플 라우팅 알고리즘에 기반한 경로를 구성함으로써 불필요한 라우팅 경로를 갖는 단점이 있다. 따라서 본 논문에서는 심플 라우팅 알고리즘보다 평균거리가 개선된 새로운 라우팅 알고리즘을 제안하고, HHN(3;3,2)를 기준으로 비교하였을 때 대략 32%정도 향상됨을 보인다.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.3
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• pp.43-51
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• 2017

MANET consists of only wireless nodes having limited processing capability. It processes routing and data transmission through cooperation among each other. And it is exposed to many attack threats due to the dynamic topology by movement of nodes and multi-hop communication. Therefore, the reliability of transmitted data between nodes must be improved and security of integrity must be high. In this paper, we propose a method to increase the reliability of transmitted data by providing a secure cryptography protocol. The proposed method used a hierarchical structure to provide smooth cryptographic services. The cluster authentication node issues the cluster authentication key pair and unique key to the nodes. The nodes performs the encryption through two steps of encryption using cluster public key and block encryption using unique key. Because of this, the robustness against data forgery attacks was heightened. The superior performance of the proposed method can be confirmed through comparative experiment with the existing security routing method.

• The Transactions of the Korea Information Processing Society
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• v.5 no.12
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• pp.3221-3229
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• 1998

본 논문은 광역 이동컴퓨팅 환경에서 계층적인 네트워크 확장에 적합한 새로운 계층적 위치수정(Location Update)과 경로설정(Routing) 방안을 제안한다. 제안된 방안은 통신을 가장 빈번하게 요구하는 고객영역(Patron Area)의 경계에 있는 일단의 방향선회(Redirection)에이전트들로 위치수정을 제한하기 때문에 위치수정의 수를 줄이게 된다. 계층적 방향선회 개념의 적용으로 고객영역 내에서 호스트 이동에 대한 위치수정 부담이 없어진다. 가벼워진 위치수정에도 불구하고 이동호스트의 홈(Home) 네트워크의 홈 에이전트를 거치지 않고 대부분의 통신이 이루어지기 때문에 최적에 가까운 경로설정을 제공한다. 제안된 방안은 위치수정 및 경로설정의 효율성 관점에서 기존의 계층 및 비 계층 위치수정 방안과 비교 분석하였다.

• Journal of information and communication convergence engineering
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• v.10 no.3
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• pp.276-283
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• 2012

Nowadays, wireless sensor networks (WSNs) comprise a tremendously growing infrastructure for monitoring the physical or environmental conditions of objects. WSNs pose challenges to mitigating energy dissipation by constructing a reliable and energy saving network. In this paper, we propose a novel network construction and routing method by defining three different duties for sensor nodes, that is, node gateways, cluster heads, and cluster members, and then by applying a hierarchical structure from the sink to the normal sensing nodes. This method provides an efficient rationale to support the maximum coverage, to recover missing data with node mobility, and to reduce overall energy dissipation. All this should lengthen the lifetime of the network significantly.

• Journal of the Korea Society for Simulation
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• v.8 no.3
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• pp.91-103
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• 1999

This paper proposes an algorithm which reduces transportation cost while goods are delivered in time in a logistics system. The logistics system assumed in this paper is the system in which multiple cars moves various goods from spatially distributed warehouses to stores. For reducing transportation cost, the car assignment algorithm which allocates goods to minimal cars employs the BF method; routing of each car is modelled as the TSP and is solved by using the genetic algorithm. For evaluating the proposed algorithm, the logistics system is modelled and simulated by using the DEVS formalism. The DEVS formalism specifies discrete event systems in a hierarchical, modular manner. During simulation, each car is modelled as a message and traverses warehouse and stores. When a car arrives at a warehouse or a store, predetermined amount of goods are loaded or unloaded. The arrival time and departure time of cars are analyzed and eventually whether goods are delivered in the desired time bound is verified.