Adversarial SQL injection (SQLi) refers to the process in which attackers dynamically modify their attack strategies based on feedback from the target Web Application Firewall (WAF) in an attempt to bypass it. The emergence of automated adversarial SQLi tools in recent years, such as AdvSQLi, RAT, and GPTFuzzer, demonstrates that adversarial SQLi has become a critical method for vulnerability detection and SQLi execution. These tools' intelligent nature poses a significant threat to existing SQLi defense mechanisms. Payloads subjected to adversarial mutation can effectively deceive machine learning-based WAFs, while rule-based WAFs are more susceptible to having vulnerabilities discovered. To address this issue, we propose a hybrid model based on enhanced Character-Level CNN (CLCNN) and Reinforcement Learning (RL), which detects malicious patterns through multi-scale feature extraction by CLCNN from a pattern-matching perspective. Additionally, the reinforcement learning module is employed for adversarial training, executing de-obfuscation operations on payloads for which the CLCNN outputs a low confidence level, further processing ambiguous payloads. The experimental results indicate that even without a priori knowledge, CLCNN demonstrates strong resistance to such tools. And the RL module can further enhance Recall through adversarial training, with minimal reduction in the hybrid model's performance on standard SQLi datasets.

Abstract Along with the rapid development of B5G/6G, the number of applications grows rapidly and the data amount explodes exponentially, putting a massive burden on the resource‐limited edge servers. To fully utilize the limited resources, virtualization technology is introduced to provide elastic deployment for applications in edge servers. But for I/O‐intensive applications, allocating elastic resources is not as easy as for compute‐intensive ones, because the amount of required I/O resources is unknown due to the request uncertainty. Many existing researches try to solve this multi‐application deployment problem by peaks clipping and valleys filling, to resource utilization. However, in fact, the times of peaks and valleys of most hybrid deployed applications are similar to each other, which invalidates those traditional solutions. To address this challenge, the actual data is analysed and complementary peak and valley periods in time and space dimensions are found. Based on this finding, an elastic hybrid deployment strategy HybridDep is proposed, for multiple I/O‐intensive applications. Validated by simulation experiments using real datasets and traces, this algorithm can reduce about 3.2% deployment cost than the compared algorithm.

Seismic data are always in low-resolution due to the limitations of seismic acquisition and processing technology, which bring challenges to subsequent seismic interpretation. Deep learning has been successfully applied to the seismic data super-resolution, all methods tend to directly learn the mapping relationship between low-resolution seismic images and super-resolution seismic images through some complex convolutional neural networks. But blindly increasing the depth of the network brings limited improvement to the super-resolution work. We propose a novel geophysical prior guided framework for seismic data super-resolution to solve this problem. Specifically, we select fault prior to guide the training of deep learning model: we use knowledge distillation technology to progressively propagate the fault prior from the teacher network (trained with the low-resolution synthetic seismic data/high-resolution fault prior and high-resolution synthetic seismic data pairs) to the student net-work (trained with the low-resolution synthetic seismic data and high-resolution synthetic seismic data pairs). To better propagate fault priors, we use feature space loss and soft ground truth loss in student network training. Finally, we use the trained student network to complete the super-resolution of synthetic validation seismic data and real seismic data. In addition, in our super-resolution framework, we directly process 3D seismic data instead of 2D seismic images, which further improves the effects of super-resolution and the subsequent seismic interpretation. Compared with the state-of-the-art seismic super-resolution method, the experimental results show that the super-resolution results of our method can depict the faults more clearly.

Geographic routing in wireless sensor networks suffers from the local minimum problem when data packets encounter the concave boundary of a hole (void area), i.e., no neighbor node are closer to the destination than the current node. In this paper, we propose a hole plastic scheme which adaptively fill the concave area of a hole with potential stuck nodes according to 1-hop information of neighbors, to relieve the local minimum problem faced by geographic routing. The basic idea is To mark the nodes located in the concave area of the hole as potential stuck nodes which do not participate in data delivery unless a source/destination is located on the concave area of the hole. Once the hole plastic process is achieved, subsequently arriving data flows will be prevented from entering the concave area of the hole by potential stuck nodes. The proposed hole plastic scheme is achieved in a local self-organized manner, i.e., potential stuck node marking is based on the information of 1-hop neighbors, and traditional multi-hop cooperation methods such as hole detection, hole boundary tracing, hole modeling are not required.

Boolean tomography is based on exploiting performance level correlations of end-to-end measurements to identify the congested links. Most work to date attempts to find the congested links according to the observed pattern of congested paths and the prior link congestion probabilities. In their work, the prior link congestion probabilities are either assumed to be unrealistically equal or estimated by a computationally complex algorithm. Furthermore, all congested paths are mapped down to the same “bad” state regardless of their congestion degrees, then separate causes of congestion may be identified as a common cause. In this paper, we propose a fast Bottom-Up Approach named BUA to estimate the prior probabilities based on a small number of measurement snapshots. BUA is computationally simpler than the existing approaches since it computes the congestion probability of each individual link through an explicit function of the measurements. We then extract the subsets of congested paths that might traverse the same congested links in current measurement snapshot according to their congestion degrees. The links that cause the congestion of each subset of paths are identified with the aid of the learnt probabilities. Simulations in different network scenarios demonstrate that our approach is able to improve the accuracy of the identification procedure.

ABSTRACT Nodes mobility brings flinty challenges to multicast in Mobilead hocNetworks (MANETs). To track nodes mobility, flooding messages are widely used for data delivery structure construction and maintenance in many multicast protocols. These periodic flooding messages significantly consume network resources, such as energy and bandwidth, and result in network collisions. To release data delivery structure maintenance onus, profited from GPS location service, a number of stateless location based multicast protocol were proposed, where a destination list is encapsulated into each data packet for data packet orientation. However, due to data packet capability limitation, the way of encapsulating a destination list in each data packet header restricts the protocol scalability. To solve the scalability issue of multicast protocols, we propose a Scalable Location Guide Overlay Multicast (SLGOM) for MANETs. Analysis and simulation results show that SLGOM achieves high performance in large multicast group and significantly improves the scalability of stateless multicast with respect to group size. Copyright © 2010 John Wiley & Sons, Ltd.

Recently, group mobility support of mobile sinks has received increasing interest, and several mechanisms have been proposed. The mechanisms typically follow a strategy that simply adopts flooding. The strategy detects the currently located region of a mobile sink group in flooding, registers the current region to a source, and performs data flooding in the region to disseminate data to the sink group. However, this strategy might cause serious problems in terms of reachability and communication overhead. In the first, although a group could continuously move toward a target point for its own mission, the strategy discretely performs detecting the group region and updating the region information. Namely, data may be delivered the previously current region, i.e. already updated but changed the region. Moreover, in order to obtain the region information of the group, flooding is frequently fulfilled as well as the strategy utilizes flooding for data delivery to the group every time. Therefore, we propose a novel strategy for reachability and low overhead, called X-Geocasting. X-Geocasting merely finds out the region of a group when the group changes direction or movement velocity. Also, instead of fully flooding in group regions, X-Geocasting predictively and flexibly determines the restricted flooding area according to direction and movement velocity. Simulation results prove this proposed group mobility support strategy provides reachability and high energy-efficiency.

Energy conservation and interference reduction are the two ultimate goals in the design of network protocols for wireless sensor networks (WSNs). Energy-aware geographic routing has been considered as an attractive routing scheme for energy conservation in WSNs owing to its desirable scalability and simplicity. However, most energy-aware geographic routing protocols seldom consider interference reduction. The authors present an energy-aware interference-sensitive geographic routing (EIGR) protocol, which focuses on minimising the total network energy consumption and reducing interference. EIGR adaptively uses an anchor list to guide data delivery, and selects the minimum-interference link from energy-optimal relay region for data delivery. To further reduce the energy consumption and interference, EIGR adjusts the transmission power of each forwarding node so as just to reach the selected next forwarding node. Simulation results demonstrate that the proposed approach exhibits noticeably higher energy efficiency, shorter end-to-end delay and higher packet delivery ratio compared with other geographic routing protocols.

Proxy Mobile IPv6 (PMIPv6) is designed to provide mobility service to IPv6-nodes in a network domain by network-based management which does not require the nodes to be involved in IP mobility management. In other words, the PMIPv6 can support roaming within a PMIPv6 domain, i.e. intra-domain roaming, transparent to mobile nodes. Recently, next generation wireless networks, such as 802.16e and Super 3G/3.9G, adopt the PMIPv6 as a management solution of the IP mobility. Such extensive adoption of the PMIPv6 might lead to frequent roaming of IPv6-nodes not only within a PMIPv6 domain but also between PMIPv6 domains. However, for the roaming between PMIPv6 domain, i.e. inter-domain roaming, existing solutions take interworking between PMIPv6 and MIPv6 into consideration. It means that every mobile node should involve IP mobility management although the nodes merely move around among PMIPv6 domains which provide the transparent node mobility service. Hence, we propose a network-based roaming mechanism between PMIPv6 domains to offer transparent mobility support to IPv6-nodes. The inter-domain mechanism takes into account concatenated tunnels between home domain and visited domain. The tunnels would be established by signaling among routers in the home and visited PMIPv6 network domains.

In wireless sensor networks, a geographic routing requests source nodes (sensor nodes) to know location information of destination nodes (sinks) to send their data. To address this issue, many sink location service schemes have been proposed in the literature. They are designed to support only one communication mode such as unicast, anycast, manycast, or multicast communication modes. However, because an application can have one or more communication modes or a sensor network can operate several applications with each communication mode, it is necessary for a scheme to support all communication modes. Hence, we propose a general sink location service scheme for supporting all communication modes. The proposed scheme modifies the basic idea of the existing one proposed for unicast communication mode and extends it for supporting all communication modes. Simulation results show that the proposed scheme is superior to other sink location service schemes when supporting all communication modes.

Geographic routing has been considered as an efficient, simple and scalable routing protocol for wireless sensor networks, since it exploits pure location information instead of global topology information to route data packets towards a static sink. Recently, a number of research works have shown that mobile sinks can achieve high energy efficiency and load balance than static ones. In order to receive data packets continuously, a mobile sink must update its location to the source frequently. However, frequent location updates of mobile sinks may lead to both rapid energy consumption of the sensor nodes and increased collisions in wireless transmissions. The authors propose a novel geographic routing for mobile sinks to address this issue. The proposed scheme takes advantage of wireless broadcast transmission nature of wireless sensor nodes. When a sink moves, the new location information is propagated along the reverse geographic routing path to the source during data delivery. Analysis and simulation results indicate that elastic routing is superior to other protocols in terms of control overhead, data delivery delay and energy consumption.

We propose a communication mechanism to support mobility of loosely coupled mobile users in sensor applications with multiple sources. First, we examine problems for mobility support of the loosely coupled users in wireless sensor networks with multiple source nodes, and then study the dynamic sink communication model to support a mobile user with sink-oriented tree based data gathering from multiple sources and data-centric unicasting. Finally, we present an energy-efficient solution to support the loosely coupled mobile users through single data-gathering tree establishment with a distributed manner and the gathering tree based data-centric multicasting.

This paper addresses issues for tracking and monitoring continuous objects, such as poison gas, biochemical, and chemical liquid in wireless sensor networks. These continuous objects are quite different from the individual objects, such as people, animals, and vehicles in that they are continuously distributed across a region and usually occupy a large area. Accordingly, they are detected and sensed by many sensor nodes, and their sensing data are redundant and highly correlated. Hence, there needs any efficient scheme on collecting and aggregating locally their sensing data and generating the data report. The continuous objects also tend to diffuse, changes in shape, increases the size, even splits into multiple smaller continuous objects, or join together one continuous object. Accordingly, there also need any efficient scheme to manage efficiently the dynamic change of shape of the continuous objects. Therefore, we introduce dynamic rectangle zone-based collaboration mechanism for detecting, tracking, and monitoring the continuous objects taking into account the dynamic change of their shape. The proposed mechanism constructs a dynamic rectangle zone included the area occupied by one continuous object. One center node in the zone collects and aggregates the sensing data from sensor nodes which detect the continuous object. The dynamic rectangle zone change newly according to dynamic change of the continuous object and the center node is also altered by another node to minimize the energy consumption for collecting the sensing data. Through simulation results, we also evaluate how environmental factors and control parameters affect the performance of the proposed mechanism.

Most existing geographic routing protocols on sensor networks concentrates on finding ways to guarantee data forwarding from the source to the destination, and not many protocols have been done on collecting and aggregating data of sources in a local and adjacent region. However, data generated from the sources in the local and adjacent region are often redundant and highly correlated. Accordingly, data collection and aggregation of the region in the sensor networks is important and necessary to save the energy of sensor nodes. We introduce the concept of a local sink to address this issue in geographic routing. The local sink is a sensor node in the region, in which the sensor node is temporarily selected by the global sink for collecting and aggregating data from source nodes in the region and delivering the aggregated data to the global sink, in geographic routing. We also design a model to determine an optimal location of the local sink and propose a mechanism to collect data through the local sink. Simulation results show that the proposed mechanism with the local sink is more efficient in terms of the energy and the data delivery ratio than the existing mechanism in a geographic routing.

In wireless sensor networks, groups of mobile users interested in equivalent information could be classified into two categories according to existence of direct communication channel among the users: 1) loosely coupled user group and 2) tightly coupled user group. The loosely coupled group means that a mobile user should communicate with others via a wireless sensor network for querying, gathering, and sharing of information interested from the group. Several information communication mechanisms have already been proposed to support mobility of the loosely coupled user groups. However, the mechanisms may not suit in case of sensor applications with multiple data sources since those are usually construct a network structure per each source. Namely, according to the mechanisms, too many network structures for the many data sources could be constructed and it may causes excessive computing overhead and energy exhaustion of sensors. Therefore, we propose an information communication mechanism to support mobility of loosely coupled mobile users in sensor applications with multiple sources. First, we examine the problems for mobility support of the loosely coupled groups in wireless sensor networks with multiple source nodes, and then study the dynamic sink communication model for data gathering from multiple sources and data delivery to a mobile user. Finally, we present an energy-efficient solution to support mobility of loosely coupled groups based on data gathering tree establishment via distributed manner and tree-based data multicasting.

We propose a communication mechanism to support mobility of loosely coupled mobile users in sensor applications with multiple sources. First, we examine problems for mobility support of the loosely coupled users in wireless sensor networks with multiple source nodes, and then study the dynamic sink communication model to support a mobile user with sink-oriented tree based data gathering from multiple sources and data-centric unicasting. Finally, we present an energy-efficient solution to support the loosely coupled mobile users through single data-gathering tree establishment with a distributed manner and the gathering tree based data-centric multicasting.

Typical information communication for large-scale wireless sensor networks may be performed in a data-centric routing manner. The data-centric routing manner well matches the publish/subscribe communication paradigm operated by a contention-based networking. The publish/subscribe paradigm provides decoupling properties for data-centric networking: space, time, and synchronization decoupling. For large-scale applications in which many publishers and subscribers are participated in interworking of information, the decoupling properties proffer salability. However, most existing communication schemes for the large-scale sensor networks do not fully satisfy the decoupling properties. The schemes construct network structures based on publishers or subscribers known as event sources and sinks respectively. Such dependency of network structures causes that network structures are established in proportion to the number of sinks or sources, i.e. space dependency. Also, originating sinks or sources of structures are always joined with the structures and manage the interworking information, i.e. dependency of time and synchronization. Hence, the communication schemes should take into account a network structure independent of the publishers and subscribers. In this paper, we propose a novel communication scheme decoupled with sinks and event sources, called ARBITER. ARBITER constructs a shared virtual grid with level value k from center point, k = 0. It then arranges storage nodes and transit nodes at level 1 cross points and over level points respectively. Sinks query to the storage nodes through the transit nodes and receive interesting information via requesting paths. Sources store sensed data to the storage nodes by the transit nodes. Our simulation proves that ARBITER shows better performance in terms of scalability, data responsibility, and mobility support.

Geographic routing has been considered as an efficient, simple, and scalable routing protocol for wireless sensor networks since it exploits pure local location information instead of global topology information to route data packets. Geographic routing requires the sources nodes to be aware of the location of sinks. Most existing geographic routing protocols merely assume that source nodes are aware of the locations of sinks or can get the locations of sinks by some service. How can source nodes get the locations of sinks was not addressed in detail. In this paper, we propose a circle path based sink location service for geographic routing in wireless sensor networks. In this scheme, a source node sends a sink location query (SLQ) message to the predefined base node and sends another SLQ message to a node on the edge of the sensor network, thus generating a SLQ path; a sink node sends a sink location announcement (SLA) message along a circle path, the centre of the circle path is the predefined base node. By this way we can guarantee the SLQ path and SLA path have at least one crossing point. The node located on the crossing point of the two paths informs the source node the sink location. How to achieve this procedure in any irregular profile sensor network is another challenge of this paper. Simulation results show that our protocol is significantly superior to other protocols in terms of energy consumption and control overhead.

Many dissemination protocols on the mobility support in wireless sensor networks have been designed based on the assumption that the movement trace of sinks is random. However, the mobility of the sinks in many applications, for example, the movement traces of a soldier on operation in a battle field or a firelight on rescue operation in the disaster area, can be determined in advance since they move in accordance with the decided operation or the drill regulation to perform their task. In this paper, we propose a Predictable Mobility-based Data Dissemination protocol (PMDD) that enables data to directly route from source nodes to moving sinks by taking into consideration predictable movement behavior of the sinks. We also compare the performance of the PMDD with those of other dissemination protocols with random movement behavior of the sinks, and show the superiority of the PMDD based on network lifetime, data delivery ratio, and delay latency.

Typical wireless sensor networks consist of sensor nodes and base-stations (sinks). The sensors, sinks, and user nodes can orthogonally provide their own mobility environments. The existing studies take only sensor mobility, sink mobility, and event mobility into account. Inquirer mobility, however, can be possibly suggested as one of the mobility models. An inquirer is one of the existing entity for sensor networks as a user. Inquirer mobility and routing mechanism to support it are proposed in this paper. For that, possible mobility environment and characteristics are also analyzed. At the end of this paper, excellence of the proposed routing model is proved through simulation results.

Sensor networks are composed of a great number of sensor nodes. Since all sensor nodes are energy-restricted and hard to recharge, it is very important. However, the energy consumption may significantly increase if mobile sources or sinks exist in sensor networks. The reason is that the routing information for mobile sources and sinks needs to be update frequently for efficient data delivery. The routing algorithm supporting mobile sinks should consider not only continuous data delivery but also the energy consumption of sensor nodes. However, most of the existing research e.g. Fan Ye, et al. (Set. 2002), Zehua Zhou, et al., (Jun 2006) focuses on even energy consumption while the mobility of sinks and sources is rarely consider. In this paper, we propose an efficient routing protocol with multiple virtual grids to reduce energy consumption and improve packets delivery efficiency. Simulation results show that our algorithm can guarantee high data delivery ratio and lower average delivery delay, while consuming lower energy than existing routing protocols in sensor networks.

Void areas (holes) as an inevitable phenomenon exist in geographic routing of wireless sensor networks, because the unpredictable and harsh nature application environment or uneven energy consumption. Most of the existing schemes for the issue tend to construct a static detour path to bypass a hole. The static detour path may lead to uneven energy consumption of the nodes on the perimeter of the hole; thus it may enlarge the hole. At the same time, traffic would concentrate on the peripheral node of the hole; thus the nodes on the perimeter of the hole tend to be depleted quickly. In previous work, we have proposed a hole geometric model to reduce the energy consumption and packet collisions of the nodes on the hole boundary. This scheme, however, still has the static detour path problem. Therefore, we extend the previous work by constructing a dynamic detour path hole geometric model for wireless sensor networks in this paper. The location of hole detour anchor is dynamically shifted according to Gaussian function, just generating dynamic hole detour paths.

Geographic routing has been addressed in many literatures of ad hoc sensor networks due to its efficiency and scalability. Void areas (holes) bring geographic routing several problems such as excessive energy consumption and data congestion of hole boundary nodes. Holes are hardly avoided in wireless sensor networks because of various actual geographical environments, e.g., puddles, buildings or obstacles, or uneven energy consumption, even physical destruction. To bypass holes, most existing geographic routing protocols tend to route data packets along the boundaries of holes by perimeter routing scheme. This scheme consumes more energy of the nodes on the boundaries of holes, thus possibly enlarging the holes, we call this hole diffusion problem. In this paper, we propose anchor node based virtual modeling of holes in wireless sensor networks to solve the hole problems faced by geographic routing in wireless sensor networks. Simulation results show that the proposed protocol is superior to other protocols in terms of packet deliver ratio, control overhead, average delivery delay, and energy consumption.

Geographic routing is attractive in wireless sensor networks especially for scalability, as it is possible to scale the network size without increasing the signaling overhead, because routing decisions are inherently localized. Geographic routing requires the sources nodes to be aware of the location of the sinks. Most of existing geographic routing protocols merely assume that the sources can get the location of sinks by some location service. How can source nodes obtain the location of sinks is not addressed in detail. In this paper, we propose an anchor node based sink location dissemination scheme for geographic routing in wireless sensor networks. In this scheme, a source node and a sink node send sink location announcement and query messages along two paths respectively by geographic routing. The node located on the crossing point of the two paths informs the source about the sink location. The challenge of this paper is that how to guarantee these two paths having at least one crossing point in any irregular profile of sensor network. Simulation results show that our protocol is significantly superior to other protocols in terms of energy consumption and control overhead.

Geographic routing has been addressed in many literatures of ad hoc sensor networks due to its efficiency and scalability. Void areas (holes) bring Geographic routing some problems such as data congestion and excessive energy consumption of hole boundary nodes. Holes are hardly avoided in wireless sensor networks due to various actual geographical environments, e.g., puddles, buildings or obstacles, or uneven energy consumption, even physical destruction. To bypass a hole, most existing geographic routing protocols tend to route data packets along the boundary of the hole by perimeter routing scheme. This scheme, on one hand, consumes more energy of the nodes on the boundary of the hole, thus possibly enlarging the hole, we call this hole diffusion problem; on the other hand, it may incur data congestion if multiple communication sessions are bypassing the hole simultaneously. In this paper, we propose efficient hole detour scheme to solve the hole problems faced by geographic routing in wireless sensor networks. Simulation results show that the proposed protocol is superior to other protocols in terms of packet deliver ratio, control overhead, average delivery delay, and energy consumption.

In wireless sensor networks, a communication model that separate a sink collecting information from sensor nodes and a user using it has been proposed. In the model, a mobile user appoints a neighborhood sensor node as a dynamic sink, and the dynamic sink collects data from all sensor nodes and forwards the aggregated data to the mobile user. In this paper, we expand the model for single mobile user to support multiple mobile users. A core of the novel model is mapping between single dynamic sink and multiple mobile users. Namely, multiple mobile users appoint a dynamic sink and the sink collect information from all sensor nodes and forward them to the multiple mobile users. To design effectively the novel model, two issues should be solved. First, the multiple mobile users without any mutual communication channel should efficiently choose and appoint only one dynamic sink. Second, the single dynamic sink should forward the collected information to the multiple mobile users. This paper proposes a solution for those issues. The solution consists of three schemes: 1) data collection scheme, 2) tree-based multicast scheme, and 3) user mobility support scheme. The data collection scheme is to solve the first issue and the tree-based multicast scheme is to solve the second issue. Also, the user mobility support scheme is to guarantee data forwarding to mobile users.

Geographic routing has been considered as an efficient, simple, and scalable routing protocol for wireless sensor networks since it exploits pure location information instead of global topology information to route data packets. Geographic routing requires the sources nodes to be aware of the location of the sinks. How can source nodes get sinks locations with low overhead is a difficult issue in wireless sensor networks. In this paper, we propose a Sink Location Service for geographic routing in wireless Sensor Networks. In this scheme, a source node and a sink node send sink location announcement and query messages along two paths respectively by geographic routing. The node located on the crossing point of the two paths informs the source about the sink location. Then the source can send data packet to the sink by geographic routing. How to guarantee that these two paths have at least one crossing point in any irregular profile of sensor network is the challenge of this paper. Simulation results show that our protocol is significantly superior to other protocols in terms of energy consumption and control overhead.

Void areas (holes) are hardly avoided in wireless sensor networks because of various actual geographical environments, e.g., puddles, buildings or obstacles, or uneven energy consumption. To bypass holes, most existing geographic routing protocols tend to route data packets along the boundaries of holes by perimeter routing scheme. Such a scheme depletes the energy of nodes on the boundary of holes faster than others and is likely to result in earlier deaths, thus enlarging the hole sizes, a phenomenon we call the hole diffusion problem. Routing along the hole boundary may also lead to increased collisions especially if multiple data streams try to bypass a hole simultaneously. In this paper, we propose virtual circle based geometric modeling of holes for geographic routing to address these problems in wireless sensor networks. Our proposed algorithm avoids routing on the hole perimeter by selecting appropriate intermediate anchor nodes (close to the hole boundary) and routing via this anchor node. We show by simulation that our proposed algorithm provides significant savings in energy consumption, shorter routing delays, higher packet delivery ratio, all with comparable control overhead as compared with state-of-the-art techniques.

Wireless sensor networks are composed of a great deal of energy restricted sensor nodes and targets (events) at long- term usage such as environment monitoring. The failure of sensor nodes caused by energy exhaustion or physical destruction may lead to the reduction of sensor areas. In the wireless sensor networks, the nodes located on the edge of holes are relatively weaker than other sensor nodes since the geographic routing scheme tends to route data packets along the edge of holes by the right hand rule. It results in more energy consumption or even exhausts the energy of the hole edge nodes, so it may enlarge the holes. We call this, aholediffusionproblem. The right hand rule may also lead to data collisions on the hole edge nodes if multiple communication sessions need to bypass a hole simultaneously. In this paper, we propose hole modeling to handle the hole problem in wireless sensor networks. Our hole modeling can efficiently prevent the hole diffusion, avoid the local minimum faced by geographic routing protocols, and reduce data collisions on the hole edge nodes. Simulation results present our protocol is superior to the previous works in terms of control overhead, average delivery delay and energy consumption.

Void areas (holes) are hardly avoided in sensor networks either because of various actual geographical environments, e.g., puddles, buildings or obstacles, or uneven energy consumption. To bypass holes, most existing geographic routing protocols tend to route data packets along the boundaries of holes. Generally, a data packet will be either forwarded along a hole boundary by the right hand rule or pushed back to find another route to its destination when the data packet encounters the hole boundary. The right hand rule, on one hand, consumes more of the nodes' energy on the boundaries of holes, thus possibly enlarging the holes; on the other hand, it may incur data collisions if multiple communication sessions share the same boundaries of holes simultaneously. In this paper, we will propose a hole geometric modeling to solve hole problem in wireless sensor networks. Our hole geometric modeling has two goals: one is to prevent data packets from traveling along the boundaries of holes; the other is to avoid the problem of local minimum phenomenon. By achieving the first goal we can not only reduce the energy consumption of the nodes on the boundaries of holes, thus preventing holes' diffusion, but also reduce the data collisions in the nodes on the boundaries of holes. The second goal can reduce the packets rerouting overhead.

Overlay multicast protocols in mobile ad hoc networks (MANET) have advantages that are low overhead and robustness in dynamic network topology by using the unicast routing protocol between group members. However, overlay data paths in overlay multicast can remain static even though the underlying physical topology is changing. Overlay multicast may lead to sub-optimal overlay data paths, since the communicating group members are not aware of the underlying physical topology. Therefore, overlay multicast protocols requires periodic control messages for the overlay data path management in dynamic environment. In this paper, we propose an efficient overlay multicast protocol (EOMP) using unicast routing information. Multicast state information of each group member in EOMP is created by its unicast routing table. Therefore, multicast data packets between group members are delivered through the overall optimal paths in physical networks. Meanwhile, the overlay data path in EOMP can be managed without periodic control messages in the dynamic environment. Finally, we evaluate EOMP performance with other multicast protocols proposed for ad hoc networks. Simulations show enhanced results of proposed protocols

Stable multicast data delivery structure contributes high data delivery ratio and low control overhead in Mobile Ad Hoc Networks (MANETs). Due to dynamic topology of MANETs, to construct a stable multicast data delivery structure becomes a challenge in ad hoc environment. In this paper, we propose a stable overlay multicast protocol for MANETs based on modified Delayed Forwarding mechanism. In this protocol, each member node precalculates its stability according to remaining battery and local mobility of itself. A source rooted overlay multicast tree is created if source has to send data packets. The overlay creation follows the stability of each member node. By using modified Delayed Forwarding mechanism, a member node with relatively high stability will have highly populated subtrees, by this way to improve multicast routing stability. Data packets are transmitted via IP-in-IP tunnels between member nodes in the overlay tree.

A characteristic of mobile ad hoc networks, mobility leads to frequently update multicast routing information based on network multicasting. For the reason, comparatively lots of control signaling messages are generated, so bandwidth of wireless media and limited battery power of mobile nodes are inefficiently consumed. To improve the shortcomings, overlay multicast protocols on application layer has been proposed; however, some of them have another shortcoming which is that the number of unnecessary data forwarding among multicast members increases. Additionally, they hardly support network scalability. Thus, this paper proposes an implicit cluster-based overlay multicast protocol exploiting tree division (ICOM-TD) for mobile ad hoc networks to improve their shortcomings. Finally, we evaluate performance of ICOM-TD through numerical analysis about complexity of multicast routing and simulation in comparison with existing multicast mechanisms for ad hoc networks on end-to-end time delay, packet overhead, and delivery ratio.

Typical sensor networks consist of users, sinks, and a number of sensor nodes. The traditional architecture usually assumes that there is a legacy network between users and sinks. However, practical users like firefighters and soldiers move around sensor fields and they might not have any direct communication through legacy networks. In other words, sensor networks are the only communication channel between users and sinks in practical sensor fields. Now there are no researches with respect to architecture to support the user mobility. Thus it is necessary to deliberate a new architecture for such the issue. In this paper, a novel communication architecture was presented where a user operates around an infrastructureless sensor field. A new networking model was then proposed, named dynamic sink model, to support user mobility on the novel architecture. In the model a sink is temporarily selected among generic sensor nodes by a user when the user wants to get information from a sensor network. The chosen sink gathers data from sensor nodes for interested tasks and propagates collected information to the user via the sensor network. The performance of the dynamic sink model on the novel architecture was evaluated and explored with regard to average delay, delivery ratio, and network lifetime compared with the common static sink network model on typical communication architecture.