Earticle

A routing strategy based on traffic prediction and dynamic cache allocation for satellite nodes is proposed to address the issues of high propagation delay and overall delay of inter-satellite and satellite-to-ground links in low Earth orbit (LEO) satellite systems. The spatial and temporal correlations of satellite network traffic were analyzed, and the relevant traffic through the target satellite was extracted as raw input for traffic prediction. An improved gradient boosting regression tree algorithm was used for traffic prediction. Based on the traffic prediction results, a dynamic cache allocation routing strategy is proposed. The satellite nodes periodically monitor the traffic load on inter-satellite links (ISLs) and dynamically allocate cache resources for each ISL with neighboring nodes. Simulation results demonstrate that the proposed routing strategy effectively reduces packet loss rate and average end-to-end delay and improves the distribution of services across the entire network.

Efficient delivery of content to areas where terrestrial Internet service is unavailable can be possible via content caching at low earth orbit (LEO) satellites. Cached content in several LEO satellites must be delivered via inter-satellite links (ISLs) with appropriate routing techniques. Until now, content caching and routing techniques have been optimized independently. To tackle this issue, the optimization of selecting a content-cached satellite and routing is jointly performed, using the example of Earth observation data cached across multiple satellites. In this paper, we first formulate a dynamic power minimization problem constrained by the queue stability of all LEO satellites, where the control variables are the selection of content-cached satellite and routing in every satellite. To solve this long-term time-averaged problem, we leverage Lyapunov optimization framework to transform the original problem into a series of slot-by-slot problems. Moreover, we prove that the average power consumption and the average queue backlog by the proposed algorithm can be upper-bounded via theoretical analysis. Finally, through extensive simulations, we demonstrate that our proposed algorithm surpasses existing independent content-retrieval algorithms in terms of power consumption, queue backlog, and fairness.

The interconnection of mobile devices in urban environments can open up a lot of vistas for collaboration and content-based services. This will require setting up of a network in an urban environment which not only provides the necessary services to the user but also ensures that the network is secure and energy efficient. In this paper, we propose a secure, energy efficient dynamic routing protocol for heterogeneous wireless sensor networks in urban environments. A decision is made by every node based on various parameters like longevity, distance, battery power which measure the node and link quality to decide the next hop in the route. This ensures that the total load is distributed evenly while conserving the energy of battery-constrained nodes. The protocol also maintains a trusted population for each node through Dynamic Trust Factor (DTF) which ensures secure communication in the environment by gradually isolating the malicious nodes. The results obtained show that the proposed protocol when compared with another energy efficient protocol (MMBCR) and a widely accepted protocol (DSR) gives far better results in terms of energy efficiency. Similarly, it also outdoes a secure protocol (QDV) when it comes to detecting malicious nodes in the network.

항공 데이터 네트워크 (ADN; aircraft data network)는 항공기 항전장비들 간 신호데이터 송수신을 위한 네트워크로써 항공기 운용 환경을 고려해 MIL-STD-1553B와 같이 고신뢰성 프로토콜이 사용되어왔다. 최근에는 고속통신의 필요성이 증가함에 따라 상용 이더넷이 ADN으로 활용되고 있으며, 적용 범위가 증가하고 있는 추세이다. 이더넷은 MIL-STD-1553B 프로토콜에 비해 고속 데이터 전송이 가능하다는 장점이 있지만, 지연시간이 길다는 낮은 단점이 있다. 본 논문에서는 ADN으로 활용되는 이더넷의 성능 향상을 위한 동적 라우팅 기법과 우선순위 기반 데이터 전송기법을 제시한다. 제시기법은 이더넷 스위치에 적용되어 네트워크 트래픽의 효율적 관리 및 고우선순위 데이터 전송시간 단축시킬 수 있다. 본 논문에서는 이더넷 스위치 기반 항공전자 네트워크 환경에서 시뮬레이션을 통해 제시기법이 기존 이더넷에서 사용되는 스패닝 트리 프로토콜에 비해 데이터 전송시간을 단축시킬 수 있음을 입증한다.

Aircraft data network (ADN) is a data networking for signal transmission among avionic systems in aircraft, and it mostly has been applied MIL-STD-1553B that guarantees high reliability considering its application environments. However, commercial Ethernet has been widely applied for ADN recently, and its range of applications have increased. Ethernet provides high speed of data transmission, however, it could not guarantee quality of service (QoS) so high as MIL-STD-1553B. In this paper, we propose dynamic routing and priority based data transmission schemes in order to improve the QoS of legacy Ethernet. Our propose schemes can be applied to Ethernet switch, and it is able to manage network traffic efficiently, and reduce the time for data transmission. We analyze the packet transmission time for both legacy and proposed schemes in Ethernet environments using simulation, and we show that our proposed scheme can reduce the time for data transmission compare to legacy spanning tree protocol.

교통 기술 및 빅데이터 기술의 발달에 따라, 지능형 교통체계와 다수 사용자에 대한 최적 운행 경로를 제공하는 수요 응답형 모빌리티를 도입하고자 하는 연구들이 진행되고 있다. 수요 응답형 모빌리티는 버스나 택시와 달리 다수의 이용객에 대해 차량 위치와 이동 경로를 분석해 탑승 정류장을 선별하고, 운행 중인 차량과 경로가 비슷할 경우 합승이 가능한 최적 경로를 계산하여 서비스를 제공한다. 본 논문에서는 여러 사용자의 이용 요청에 대한 다중 경로를 계산하는 동적 라우팅 시뮬레이터를 개발하였다. 시뮬레이터 평가에 앞서 세부 시스템을 소개하고자 한다. 또한, 차량 배차 규칙에 따른 시뮬레이션 과정과 운행 효율 평가 방법을 설명하고자 한다. 시뮬레이터 평가를 위해 인천 영종도의 가상 배차 요청 데이터를 이용한 실험을 진행하였다.

이 논문은 IPTV, 원격 교육/건강과 같은 다중 사용자와 인터넷 브로드 캐스팅의 통신을 제공하고 멀티캐스트 라우팅 네트워크의 공유 경로를 구성하는 휴리스틱 알고리즘을 제안 한다. 노드 사이의 최대 지연의 측정, 평균 지연, 지연된 측정은 성능 분석을 위해 도입하였다. 알고리즘 성능의 열거 방법은 최저 지연과 함께 공유된 경로를 찾기 위한 최적된 솔루션을 사용하여 비교하였다. 라우팅 네트워크 하단의 노드들 사이의 지연을 균등하게 분배하고, 다른 알고리즘 보다 지연 추정을 이용한 알고리즘이 우수한 시뮬레이션 결과를 보여준다.

This paper proposes a heuristic algorithm to construct a shared-route in multicast routing networks that provide communications between multi-users such as IPTV, remote educations/health, and internet broadcasting. The measures of maximum delay, average delay, estimated delay between nodes are adopted for performance analysis. The performance of algorithm is compared with the optimal solution in which enumeration method is used to find the shared-route with minimum delay. Under the routing network with the uniformly distributed delay between nodes, the simulation results show that the algorithm using the estimated delay outperforms the other algorithms.

본 연구는 MOD 환경에서 규칙 기반 및 최적화 기반 배차 전략의 성능을 비교하기 위해 동적 라우 팅 시뮬레이터를 설계·구현하였다. 시뮬레이터는 실제 도로망 기반 경로 탐색과 요청 관리 기능을 포 함하며, 다양한 환경에서 전략별 응답 시간, 실차율 등을 정량 평가한다. 이를 위해 인천 영종도 지역 I-MOD 서비스 데이터를 기준으로 모의 운행 결과에 대한 검증 및 평가를 시행하였다.

본 논문에서는 모바일 ad-hoc 무선 센서 네트워크에서 효과적인 경로 안정성을 지원하기 위한 엔트로피 기반의 동적 라우팅 프로토콜을 제안한다. 제안된 라우팅 프로토콜의 기본 아이디어 및 특징은 다음과 같다. 첫째, 소스노드와 목적지 노드 사이의 안정된 라우팅 경로의 설정이다. 본 연구에서는 모바일 노드들의 이동성 정보와 전력 정보를 동적으로 이용한 엔트로피 기반의 안정된 경로 설정방법을 제안 사용한다. 둘째, 경로 설정에 필요한 자원 절약을 지원하기 위해서 노드들의 위치 및 방향성 정보를 이용한 방법을 사용한다. 셋째, 기존의 센서 네트워크는 주로 고정된 노드 환경에서 많은 연구가 되어 왔지만, 본 연구에서는 노드들의 이동성을 고려한 환경에서 연구가 이루어진다. 제안된 라우팅 프로토콜의 의 성능평가는 OPNET (Optimized Network Engineering Tool)을 사용하여 이루어졌으며, 성능평가를 통하여 제안한 프로토콜은 효과적인 경로의 안정성 지원 및 데이터 전송효율 보여 주었다.

In this paper, we propose an entropy-based dynamic routing protocol for supporting effective route stability in mobile ad-hoc wireless sensor networks(MAWSN). The basic ideas and features are as follows. First, construction of entropy-based stable routing route using mobility of nodes between a source node and a destination node. Second, usage of location and direction information for route construction to support resource saving. Third, We consider a realistic approach, in the points of view of the MAWSN, based on mobile sensor nodes as well as fixed sensor nodes in sensor fields while the conventional research for sensor networks focus on mainly fixed sensor nodes. The performance evaluation of the proposed routing protocol is performed via simulation using OPNET. The simulation results show the proposed routing protocol can effectively support route stability and packet delivery ratio.

Recently, according to increasing the network traffic in the IMS, the role of Network Management System (NMS) is very important because of limited network resource. It can perform two kinds of routing ways with the capability of static or dynamic routing. A dynamic routing way is more efficient than static routing one because it can make the flow of traffic changeful among nodes in the IMS. Therefore, in this paper, we suggest a management function of NMS, applying a dynamic routing algorithm for managing the CSCFs in the IMS. And then we analyze the algorithm by measuring the performance of PoC and presence service one of the prominent application services to be deployed in the IMS.

Power consumption in wireless ad hoc networks is an important design concern in the modern network research scenario. It is a concern because wireless nodes run with the help of battery and it has a limited life time period If the power failure of mobile node occurs it affects not only its ability to forward packets to destination but also its ability to forward packets on behalf of others and hence overall network lifetime. Moreover, it is very difficult to replace or recharge a mobile node powered by batteries so in order to maximize the life time of nodes routing of traffic should be in such a way that power consumption is minimized. Hence, every effort is to be channeled towards reducing power. More precisely, network lifetime is a key design metric in MANETs. Our main contribution in this thesis is Power Efficient Dynamic Source Routing (PEDSR) protocol, satisfying less power consumption from the viewpoints of nodes and network. To achieve our goal, first, we studied DSR protocol using performance and power aware metrics. Modifications are done on the Dynamic Source Routing (DSR) protocol by taking into consideration the outcomes of the pre-simulation, the existing feature of DSR for implementation of the design, and the previous research works done on DSR routing protocol by many researchers. Subsequently, we studied the performance evaluation of our proposition. The simulation results show that the power aware routing protocol, PEDSR outperforms the original DSR protocol in majority of the scenarios and evaluation metrics.

In MANET, establishes the network no depends on the infrastructure and communicates. The topology is exchanged following the various conditions. Also the routing path is disconnected due to node mobility and direction of node. To solve these problems, we proposed the Load Tolerance Density-distribution (LTD) algorithm on dynamic density in mobile ad hoc networks. The proposed algorithm measures the dynamic density and load balance then it calculates the relationship between the cluster head nodes by the homogenous routing (passion) distributed procedure and provides the distributed routing path density in mobile ad hoc networks. In the simulation, we compare the LTD algorithm and the WCA algorithm and the Max-min algorithm. As the simulation results, the proposed algorithm improves the packet delivery ratio of various conditions in the clustering routing.

For the dynamic of the number of rescue nodes, the number of person at the rescue node, the number and location of rescue boats, the uncertainty of rescue time (travel time of boats and rescue time of workers), the paper established a dynamic fuzzy rescue time Location-Allocation Problem (LRP) model. To ensure that the decision makers could make new decisions in a very short period of time according to the dynamic data update. A matching hybrid genetic algorithm containing heuristic rule was introduced according the characteristics above. The algorithm used three-stage real-code that represents the search order of boats. The search order and the heuristic rule determined the rescue completed moment of each rescue nodes. The simulated test analysis shows the validity and the correctness of the model and algorithm.

Machine-to-machine (M2M) communication brings numerous challenges in security which traditional communication models have not yet addressed. Particularly, due to their inherent unguarded, low- cost, and mass-deployed nature, M2M devices would invite new threats in security with the collaboration of multiple entities to perform collaborative tasks that rely on communication. This paper considers the security issues at network layer, where in routing and packet forwarding are the main operations. We propose a novel efficient security scheme in order to provide various security characteristics, such as authentication, confidentiality, integrity and non-repudiation for machine to machine networks. In our security mechanism, we implemented the adaptive identity-based signcryption to define the proposed security mechanism in context of dynamic source routing (DSR) protocol. Without any assumption of pre-fixed trust relationship between nodes, the wireless network works in a self-organizing way to provide key generation and key management services using secret sharing algorithm in the traditional public-key infrastructure (PKI).

Now-a-days the transportation network traffic plays a vital role in the society. People are focusing on arriving at our destination as quickly as possible. With this lifestyle, people are not always aware of all the traffic conditions that are experienced while operating an automobile. In the existing system, reduction of green house gas emissions from transportation network based on road network graphs where all edges are annotated with accurate weight that capture environmental cost, fuel usage are needed for eco-routing. However, such weights are not readily available on the road network. So, randomly assign the weights for each road segments and it typically lack the speed pattern of the road network. This paper address these limitation, proposes two stage routing algorithm and weight propagation model to predict the cost of an arbitrary path on road network and accurately detects the traffic environment and also provides the optimal alternate route for destination.

Loads of research work and efforts have been done since last decade to provide support and solution to different problems and challenges related to mobile ad hoc networks. But still the fast growing technology needs attention in many areas such as routing, bandwidth, security, power consumption, collisions, simulations, and topology control due to moving nodes. In mobile ad hoc network we cannot use the existing techniques for better quality as we are using in fixed wireless network for better efficiency. In this paper we not only compare the performance of ad-hoc routing protocols in order to prove its correctness, efficiency, traffic load and end to end delay in dynamic intermediate nodes senario but also to implement OPNET simulator in AODV and DSR routing protocols. we proposed OPNET simulator to check performance with respect to different parameters that mobility model changes have a significant impact on their performance in different ways to support QOS. By proposing OPNET which results the combined performance of both AODV and DSR routing protocol could be best solution for routing in MANET, instead of separate performance of both AODV and DSR and also in intermediate nodes data transfer rate from source to destination.

기존에 제시된 ad hoc 라우팅 프로토콜에는 안정성에 대한 부분이 고려되어 있지 않다. 본 논문에서는 기존의 DSR ad hoc 라우팅 프로토콜에 안정성을 접목한 SDSR 라우팅 프로토콜을 제시한다. SDSR은 DSR에 안정성 제공을 위해 abnormal node detector와 neighbor table이라는 것을 추가한다. abnormal node detector는 네트워크 내에 abnormal 노드를 탐지해 네트워크에서 고립시켜 네트워크에 안정성을 제공하고 neighbor table에 있는 priority를 값에 따라 이웃 노드에서 들어온 패킷을 처리함으로써 효율적인 처리 능력을 제공한다. 본 논문에서는 abnormal node detector와 neighbor table을 통해 어떤 방식으로 네트워크에 안정성을 제공하는지 살펴보도록 하겠다.

In this article, a tomography for the estimation of the origin-destination(OD) traffic intensities in dynamic routing network is considered. Vardi(1996)'s approach based on fixed route is not directly applicable to dynamic routing protocols, which arises from the fact that we cannot access the route at every observation time. While it uses link-wise traffics as the observations, the proposed method considers the triple of ingress/outgress/relayed traffics data at each node so that we can transform the problem into a routing-independent tomography. An EM algorithm for implementation and some simulated experiments are provided.

통신 노드들이 이동 중인 mobile ad hoc networks에서, 통신처리율에 따라 노드 쌍들의 순위를 결정하면, 이를 바탕으로 전체 네트워크의 처리율을 향상시키는 동적인 라우팅을 할 수 있다. Balanced Howell rotations는 브리지 게임을 위한 토너먼트 구성 방법의 하나이다. 본 논문에서는 mobile ad hoc networks의 전반적인 통신 처리율 향상을 위해 balanced Howell rotations를 활용할 수 있음을 설명한다. 그리고 balanced Howell rotations가 존재할 수 있는 조건을 제시하고, 이를 증명한다.

In mobile ad hoc networks where the communication nodes are moving around, one may perform dynamic routing that can increase the total communication throughput of the network, by determining the ranks of pairs of nodes according to their communication throughput. The balanced Howell rotation is a tournament design scheme for bridge games. This paper explains that the balanced Howell rotation can be applied to enhance the overall communication throughput of mobile ad hoc networks, and proposes and proves the condition under which the balanced Howell rotations may exist.

Dynamic Source Routing(DSR) 프로토콜은 이동 노드의 Multi-hop wireless ad hoc 망사용을 위해 특별히 디자인된 효율적인 라우팅 프로토콜이다. DSR은 일한 관리 없이 운용될 수 있도록 자기구조화 되어있으며 자기조직화 되어있다. "Router Discovery"와 "Router Maintenance"의 두 매카니즘으로 프로토콜은 구성되어 작동하며, 전적으로 on-demand로 작동한다. 본 논문에서는 multi-hop wireless ad hoc 망 상에서의 DSR 프로토콜 동작을 살펴보고, 시뮬레이션을 통한 DSR 프로토콜의 성능을 도시하여 DSR 알고리즘을 분석하고자 한다. DSR 알고리즘을 분석하고자 한다.

Dynamic Source Route(DSR) protocol is a simple and efficient routing protocol designed specially for use of the multi-hop Ad Hoc Network. DSR allows the network to be completely self-organized and self-configured without the need for any existing infrastructure or administration. DSR protocol consists of the two mechanisms of Router discovery and Router Maintenance, works entirely On-demand in all aspects. In this paper, we will present the performance of DSR protocol on the multi-hop wireless Ad Hoc Networks, illustrate it with simulation, and then analysis the algorism of DSR.