bluuebunny/crossref_metadata_2025 huggingface dataset:
Outcome after endovascular revascularization of atherosclerotic renal artery stenosis
Authors: Eklöf H. , Bergqvist D. , Hägg A. , Nyman R.
Published: January 2009

Background: With an aging population, more patients might be treated for atherosclerotic renal artery stenosis (ARAS). The goal of this treatment is to achieve a dialysis-free life or a well-controlled blood pressure with reduced risks of cardiovascular complications.

Purpose: To analyze the clinical outcome of percutaneous transluminal renal artery angioplasty without stenting (PTRA) or with stenting (PTRS) for ARAS at one center.

Material and Methods: The study group comprised 152 patients who underwent 203 PTRA/PTRS. All had hypertension, and 45% had azotemia. A retrospective collection of baseline and postprocedural number of antihypertensive drugs, blood pressure, and serum creatinine were analyzed during a follow-up of 3–18 months.

Results: Technical success rate was 95%, and clinical benefit was seen in 63% of patients. Complications included a 30-day mortality rate of 1.5%, a total complication rate of 35%, and major adverse events in 13%. The major adverse events were highly related to azotemia. Major adverse events within 30 days, with permanent disability, were seen in 5% and almost exclusively in patients with moderate or severe renal impairment. A subgroup analysis of 28 patients with renal duplex resistive index (RI) pre-PTRA/S and 6 months’ follow-up showed a benefit of PTRA/PTRS in 17 (68%) of the 25 patients with RI <80 and in all three (100%) of the patients with RI ≥80.

Conclusion: Endovascular treatment of ARAS has an excellent technical success rate, with a clinical improvement rate of >60%. However, it is associated with a considerable complication rate. Serious complications are seen mainly in azotemic patients. Predictors of clinical response could not be identified. Renal duplex RI is questioned as a predictor of clinical outcome.
Optimum Resource Allocation in Distributed MIMO Systems
Authors: Cao Rui , Yang Liuqing
Published: January 2009

Distributed multi-input multi-output (MIMO) system is a promising architecture to provide reliable communications over spatially separated relaying nodes. In this paper, we will investigate the optimum resource allocation techniques in distributed MIMO systems, employing differential (de)modulation and various relaying protocols. Instead of limiting to energy optimization, we solve this problem via a two-dimensional energy and location optimization. The benefits of our resource optimization approaches are illustrated through extensive analysis and simulations. Both the comparisons between different optimization techniques and systems with different protocols are included.

Based on our previous work, we provide an upper bound of the symbol error rate (SER) for decode-and-forward (DF) systems and an approximated SER for amplify-and-forward (AF) systems. We proved that the system SER is a convex function in both the transmit energy and the relay location, and then carried out the two-dimensional energy and location optimization through numerical search. As we know, system energy is a limited resource, especially for mobile terminals, and the coverage area is a critical factor to judge the system performance. Therefore, we evaluate the benefits of our optimization techniques in terms of the system energy saving and the coverage distance extension.

The simulations reveal several interesting results. For both the DF and the AF protocols, the optimized systems always outperform the unoptimized systems with either less energy consumption or longer transmission range. It is also noticed that the benefits of both energy and location optimizations vary a lot for different protocols, and with different system configurations. Uniform energy allocation and midpoint relay location are normally chosen as an initial system setup. For such a configuration with the DF protocol, location optimization is more critical than energy optimization, and the unoptimized system receives prominent benefits from both optimizations, and tremendous system resources savings. For the AF protocol, however, the location and energy optimizations are equally important for the unoptimized system. It turns out that the uniform energy allocation and the midpoint relay location result in fairly good system performance, since it is reasonably close to the global optimum.

For other initial system setups, the optimization benefits are also distinct in the AF and the DF systems. In DF systems, more optimization benefits can be achieved when the relays are either close to the destination or have more transmit energy allocated to the relay(s). On the contrary, in the AF systems, remarkable optimization benefits will be achieved when the relays are far from the midpoint, or when the relays are only able to transmit at low energy levels.
Knowledge Management in Global Software Development
Authors: Shiva Sajjan G. , Lee Sarah B. , Shala Lubna A. , Simmons Chris B.
Published: January 2009

In today's global economy, shrinking business cycles and global competetition are changing the landscape of software development. Frequently, multiple and geographically dispersed development teams are working together on large complex software systems. The complexity of global software development (GSD) warrants investigation into practices for building highly effective geographically diverse teams. GSD introduces challenges such as physical distance, time-zone differences, and diversity of languages and cultures. Frequently, different parts of an organization might use different terms and naming schemes and may have unique ways of expressing concepts. Knowledge of dependencies between software components and a variety of technical platforms must be recognized and shared across the organization. Such a global environment requires a high degree of collaboration and knowledge sharing. The use of a flexible, user-friendly knowledge management system that allows natural language query processing across knowledge captured throughout the software development lifecycle (SDLC) is required to improve knowledge sharing and reuse.

A variety of knowledge management techniques can be introduced into the SDLC to enhance the understanding and knowledge sharing between dispersed team members. Within the commercial realm, applications to capture and effectively disseminate knowledge are becoming more prevalent; however, many are specific to a business domain rather than focused on facilitating knowledge sharing across the SDLC.

A high level design of a system that provides an integrated view of work products extracted from different sources in the enterprise, providing “just in times” knowledge to the user either through explicit search capabilities or through intelligence-based alerting that notifies users of new knowledge, is proposed. Our proposed KMS architecture seeks to facilitate a knowledge sharing environment by stressing ease of retrieval through natural language querying and proactive notification. The KMS should be designed to present the most relevant knowledge to the user. With knowledge stored in a variety of formats and on different technical platforms, it is imperative that a tool be provided that will be able to integrate and correlate knowledge from different sources and enable ease of extraction.
Qos Min-Min Scheduling Strategy
Authors: Wan Benting
Published: January 2009

Task arriving time of a heterogeneous distributed system is stochastic. In order to make the heterogeneous distributed system satisfy user Qos (Quality of Service) requirement and transact tasks as much as possible and keep load balance, the Qos Min-Min scheduling strategy is described, which is composed of urgent Qos Min-Min scheduling strategy and high priority Qos Min-Min scheduling strategy and periodic Qos Min-Min scheduling strategy. In this paper, tasks are classified as urgent, high priority, and common task. The properties of urgent task are when it arrives at the system, it should be executed immediately and cannot be discarded by the system. The properties of high priority task are when it arrives at the system, it should be assigned and executed by the system as soon as possible without affecting elimination of the assigned task. Tasks other than the above two are defined as common tasks. When the urgent task arrives at the system, it will be assigned immediately to the system by urgent Qos Min-Min scheduling strategy, so urgent Qos Min-Min can guarantee that urgent task can be executed by the system. When high priority task occurs, it will be assigned immediately to the system by high priority Qos Min-Min scheduling strategy, so high priority Qos Min-Mint can reduce the ratio of the task discarded. Periodic Qos Min-Min scheduling strategy inserts common tasks into an appropriate position of the exact queue in the system, so periodic Qos Min-Min can also reduce the ratio of task discarded. Compared with Min-Min schedule strategy, Qos Min-Min can reasonably reduce the ratio of task discarded and improves utilizable CPU ratio. Implementing results show that the performance of Qos Min-Min is better than Min-Min.
A Domain-Based Trust Model in Peer-to-Peer Environment
Authors: Xu Fen , Guo Yajun
Published: January 2009

In large scale peer-to-peer networks, it is difficult to establish the trust relationship between peers as it is less likely that repeatable interactions will occur with the same peer. So the network is vulnerable to malicious peers.

In order to settle the problem, a novel domain-based trust model is proposed in this paper. This model can be used to deal with trust relationship between the entities in peer-to-peer environment and help peer-to-peer entities make trust choice. Select a node whose performance is the optimal as a super-node in each domain of nodes. Some information of nodes in this domain is stored in super-nodes. There are a lot of this kind of domains in the whole peer-to-peer structure, and super-nodes in each domain are connected in the form of the pure peer-to-peer structure in the overall structure. This model divides the trust relationships between entities into a trust relationship in domain and the trust relationship between domains which are dealt with in a different way. This model can evaluate the trust relationship between the entities more accurately, thus can solve security issues more effectively in the peer-to-peer environment.

We present the implementing process of this model, and propose several formulae to respectively calculate the trust value in the domain and the trust value between domains. Furthmore, the simulation and analyses show that this model can get more real trust value at the small price, and the advantages of the model are simple structure and high reliability.

In conclusion, we propose a novel domain-based trust model based on the super-node network architecture. The structure of this model is very simple. The model is very easy to be accepted by users and is suitable for many kinds of peer-to-peer application environments. The trust relationships between entities are divided into trust relationship in the domain and a trust relationship between domains in the model. For the different trust relationships, we use the different calculation method to assure the real-time performance, accuracy, integrity, and calculation efficiency of the trust value. In future, we will make much more specific definition and description for this model such as updating the strategy of the trust value and so on. We will also incorporate intrusion tolerant intelligence in this model, so that nodes are able to detect false information sent by any malicious node.
Supporting QoS-Based Discovery for Visualization Web Services
Authors: Shua Gao , Chub Xiuming , Chen Dingfang
Published: January 2009

Collaborative and distributed visualization applications generally require access to high-performance and high-end resources that are both expensive to own and maintain. Often there are also a limited number of such resources available. The development of Grid infrastructure allows these resources to be shared by visualization service providers and users. However, effective use of such resources necessitate the development of mechanisms which take into account the particular constraints needed to satisfy particular application resource demands as some visualization applications may be dependent on requiring data to be stored and delivered in a timely manner. Therefore, these applications must adhere to stringent real-time constraints and Quality-of-Service (QoS) requirements. In this paper we proposed a novel approach to matching visualization service requests with service advertisements using QoS attributes. Five attributes—Response time, Availability, Execution price, Memory capacity, and Number of CPUs—are selected as the quality criteria for the visualization services, and for each one, we provide a definition, indicate its granularity, and provide rules to compute its value for a given service.

The idea behind QoS-based matchmaking for visualization is an attempt to provide visualization service requesters with an approach to locate services, which have been selected by function properties, utilizing non-functional properties in order to get “good” quality services. The matchmaking approach proposed is concerned with computing the similarity between service requests and services based on above QoS attributes. The paper gives the equations of the similarities for Response time, Availability, Execution price, Memory capacity, Number of CPUs, and details the matching algorithm based on these equations for similarity.

A prototype of the visualization service discovery system was developed, which is based on QoS and extends our previous prototype of the semantic portal for the discovery of the visualization service which provides multiple techniques to search available visualization services. But these techniques are all based on functional attributes, not on QoS ones. The enhanced system introduces the computation of QoS similarity and the capability of QoS feedback to users, which will be faster in finding qualified visualization Web Services. The paper discusses the prototype's architecture and how it works.

The paper finally presents an experiment, the objective of which is to observe the performance of the search with QoS attributes. It can be seen from the experiment that the time for QoS matching is acceptable, and the search based on nonfunctional attributes allows the user to locate more appropriate visualization Web Services.
Anonymity Authentication and Measure in Ubiquitous Computing
Authors: Yajun Guo , Huifang Yan , Rong Li
Published: January 2009

Authentication and anonymity usually are inconsistent. To obtain services, a user must be authenticated. Much of the sensitive information of the user will be exposed to service providers. In order to protect privacy, users must communicate with service providers in an anonymous way. But if the user does not show his true identity, how can the service provider believe that the user is true. This paper presents a secure anonymity authentication protocol for ubiquitous computing which allows service providers to authenticate anonymous users. Anonymity is achieved by separating the linkability of the user's identity information and the action of the user. By finding out objects linkability relationship, we also address an anonymity measure to analyze anonymity and detect the concealing security exposure.

1. Anonymity Authentication

There exist three principals in the anonymity authentication protocol: the user, the service discoverer, and the service provider. The anonymity authentication protocol contains two authentication stages. First, the authentication between the user and the service discoverer which determines the user whether he has the right to access the requested resource. And then the service discoverer makes use of blind signature on the user's public key as a ticket. Second, the service provider authenticates the user, in which the service provider judges the user whether is the genuine user.

2. Anonymity Measure

Linkability is the relation between objects (such as subjects, events, actions etc.) in a system before and after an action occurs. Unlinkability is the sufficient condition of anonymity.

Definition 1 (function decision) Let R denote the object set, X and Y be subsets of R, and X≠ Y. If Y can be known from X with probability p, then say X function decision Y, recorded as: X→ Y( p).

Definition 2 (function decision set) To the object set R, the function decision set is the set F of function decisions among the objects known by attackers.

Definition 3 (function decision implication) If F is the function decision set known by attackers, let R denote the object set, X and Y be subsets of R, and X≠ Y. If X→ Y( p) can be deduced from F, then say F implication X→ Y( p).

Definition 4 (function decision closure) All the function decision sets implicated by F are called the closure of F, written as F+.

Whether user anonymity is protected can be judged by seeing if there are relations between users' location/actions and users' identity in F+.
Intersection-Aware Channel Assignment and Routing in Multi-Channel Multi-Hop Wireless Networks with a Single Transceiver
Authors: Chuanhe Huang , Yong Cheng , Ling Yang , Wenming Shi , Hao Zhou
Published: January 2009

This article proposes an intersection-aware channel assignment and routing protocol for wireless ad hoc networks with a single transceiver. This protocol increases the network capacity of an IEEE 802.11 network by exploiting frequency diversity. Using the proposed protocol, multiple communications can simultaneously take place in a region without interfering with each other. However, it must avoid a multi-channel hidden terminal problem for designing channel assignment and routing protocol. This paper considers issues regarding multiple channels at the network layer, assuming a single channel MAC protocol such as IEEE 802.11 DCF. Also, the proposed protocol assumes that each node in the network is equipped with a single transceiver. This set of assumptions is very practical, because most devices have a single wireless card implementing the IEEE 802.11 DCF protocol. Each node uses modular exponentiation congruence to represent the channel schedule, which assures that each pair of nodes has common channels for communication in every cycle. Each node switches across channels in such a manner that each pair of nodes works on the same channel when they desire to communicate; otherwise they work on a different channel, and hence do not interfere with each other. However, for the intersecting node, there is no benefit in using single radio multiple channels since the capacity around the intersection node can at most be O (W), W is the link capacity, regardless of the number of channels. The protocol lets the intersecting node always work on the same channel whereas the nonintersecting node can work on different channels.

The two states for every node in the network are the state of an intersecting node and the state of non-intersecting node. Using the proposed protocol, nodes discover multiple routes to the destination node; the node selects the path with most intersecting nodes to avoid more nodes become intersecting nodes when the number of flows increases greatly. Once a node becomes an intersecting node, it will work on the same channel in a cycle. Simulation results show that the proposed protocol significantly increases the aggregate end-to-end throughput and network capacity greatly over a single-channel protocol and some other channel assignment and routing protocols in several wireless networking scenarios.
The Research of Multiparty Application Modeling Supported Network Architecture Description Method
Authors: Yuan Huang , Jun Shen , Jinjing Song
Published: January 2009

The multiparty applications pattern of network is going to definitely play an important role on the Internet. However, the traditional research of network architecture almost exclusively uses the “one to one” direct interaction model to describe various kinds of network interactions. The INSA (Interactive Network Services Architecture) reference model and network description language INSADL developed by the Laboratory of Computer Network and Information Integration (Southeast University) have introduced the component-based thought and interactive viewpoint to the research of network architecture. Moreover, INSADL has provided support for the modeling of network multiparty applications to some extent.

Nevertheless the modeling requirements of the multiparty applications are much more complicated than those of traditional network applications. The description of complex network interactions involving a non-fixed number of participating entities needs to be supported. It also raised the problem of how to represent the composite entity components, and sometimes the dynamic joining and leaving of entities from interactions should be dealt with. Therefore, INSADL still has some limitations. So we established a new network architecture formal description method on the basis of INSADL's component-based thought to support the depiction of multiparty application.

We discussed the detailed modeling schemas for different modeling elements. For entity components, we defined the inheritance relations between component classes by using the “extends” field and set rules for the overriding of grammar units in derived classes. We also introduced the “symbol transformation method” of CSP to simplify the definition of similar processes. Furthermore, the definition production of functions which describe the data processing of entities is given. For the modeling of the interaction connector, we improved the description used by INSADL. We adjusted the production of nonterminal , and add a new nonterminal . Thus an uncertain number of roles in an interaction connector can be explicitly denoted. Concerning the connection configuration, we took a similar measure as interaction connector to alternate the definition of nonterminals related with the instances of entity component classes, using multiplicity expressions within the brackets to specify the number of instances.

This paper establishes a foundation for further research of the multiparty application network system's properties using the formal method.
Duty-Oriented Hybrid Peer-to-Peer Network Based on Metadata
Authors: Li Kan , Sun Xin , He Yue
Published: January 2009

The topology structure of the peer-to-peer overlay network is a critical factor in dominating performance of resource discovery. In the paper, we consider that nodes have their duty or function in the real world, and we take full advantage of the characteristic of unstructured peer-to-peer network. According to these, a duty-oriented hybrid peer-to-peer network based on metadata (DHPM) is proposed.

DHPM organizes nodes into a tree-structure hierarchical overlay network. Its nodes are divided into domains according to the duty or the function of these nodes, and into groups according to the semantic similarity in one domain. The DHPM overlay network consists of two types of nodes, super peers (SPs) and peers. A super peer is a node that acts as a centralized server submitting and answering requests on behalf of peers. A peer submits queries to its super peer, searches for the location of queries according to the metadata directory in the super peers and receives results from the real resource location. The super-peer architecture adopted in DHPM exploits the heterogeneity of nodes by assigning additional responsibilities to higher-capacity nodes. The classification of nodes helps to increase searching efficiency during routing messages in the network.

In DHPM, peers query resources via metadata directory which is in the super peers. Metadata directory in the 1st level SPs manages the information of shared resources in their domains, while metadata directory in the 2nd level SPs manages the shared information in their groups. The metadata directory is a tree-like distributed infrastructure. In the first layer of the metadata directory there are all the 1st level SPs and replica directory. 1st level SPs manage all the metadata of shared resources in the domain. The metadata of shared resources include databases, files, monitoring information, and 2nd level SPs in the domain.

In order to construct and maintain DHPM, node join algorithm, node departure algorithm, and query searching algorithm are presented to ensure running of the network. Duty or function is the important factor in selecting the super peers. In addition, high bandwidth, sufficient searching process power, longer online time etc. are the considered factors. In node departure algorithm, we describe two kinds of node departure cases: normal departure and abnormal departure. By means of metadata directory, query searching can be gotten in DHPM.

Finally, experiments are made to show the performance of query searching with DHPM, Gnutella, and Freenet.
Study on Modeling of Container Terminal Logistics System Using Agent-Based Computing and Knowledge Discovery
Authors: Bin Li , Wen-Feng Li , Yu Zhang
Published: January 2009

Container terminal is the transfer hinge of land-sea intermodal transportation. Container terminal logistics system (CTLS) is the central handling platform of container logistics in logistics network as the computer system is the core processing node to information flow in internet. Quay side is its “central processing unit (CPU)” of handling platform and storage yard is its “main memory.” CTLS is a highly complex system which includes parallel, negotiation, and competition relations etc. in operation so that this paper introduces agent based computing (ABC) and knowledge discovery in database (KDD) to model CTLS.

Logistics, information flow, and decision flow are the kernel of transaction and operation of container terminals which are developing into professional third party logistics (TPL) and seized of enormous business data which are accumulated by the inner information infrastructure and the public electronic commerce (EC) platform. Through the analysis to the handling operation and container logistics of CTLS, we refer to the design thinking of computer organization and architecture and introduce the resource scheduling thinking of the operation system, and draw an analogy between CTLS and parallel computer architecture based on Harvard architecture, map and carve up the production, and scheduling system of CTLS into fourteen kinds of agents: berth allocation agent, quay crane allocation agent, storage yard management agent, yard crane allocation agent, container truck dispatch agent, tugboat dispatch agent, gate house management agent, berth agent, quay crane agent, yard agent, yard crane agent, container truck agent, tugboat agent, and gate house agent according to the entities and their mutual relations. We bring forward the modeling framework of CTLS based on multi-agent and KDD which provides the engine to drive the model accordingly.

This modeling thinking and framework, which serves the turn to the queuing theory inherently and possesses the top-ranking flexibility and robustness to the computational intelligence (CI), can help to set down the production scheduling plan and support the important decision-making of the port. A simulation to the quay side is implemented by the AnyLogic 6.2 and SQL Server 2005 and berth allocation based on practical data is given emphasis to discuss. The simulation result precedes the quondam research and actual data to 5.14% and 26.82% through the dynamic priority scheduling. In addition, a series of similar simulations are executed to support the decision on the proportion between berth and quay crane. All verify the feasibility and creditability of the above idea and the effective scheduling strategy in the framework will be further discussed and studied when the container terminal is provided with the multifarious characteristics in the future.
An Efficient and Robust Self-Storage P2P Reputation System
Authors: Hao Liming , Lu Songnian , Tang Junhua , Yang Shutang
Published: January 2009

For the large scale of the network and unreliable nature of peers in most P2P (Peer-to-Peer) systems, it is a challenging task to implement an efficient and robust P2P reputation system. Self-storage P2P reputation systems provide an efficient way to retrieve rating values. Since each peer locally stores its own rating values given by all other peers, it takes only one query message to collect all the rating values of a peer. However, it also gives the owner control over its rating values. One of the challenges of this type of system is to protect the rating values from being maliciously modified by their owners. In existing self-storage P2P reputation systems, other participants are involved in order to ensure the integrity and reliability of the rating values. However, because at least one participant must be contacted during the rating and rating values retrieval processes, they create a high message overhead when deployed in unstructured P2P systems.

In this article, we address the efficiency and robustness of P2P reputation systems in fully distributed environments. We propose an innovative self-storage P2P reputation system. In our system, each peer locally stores its own positive rating values given and signed by other peers. On one hand, since it is not likely for a peer to discard any part of the positive rating values or forge the raters' signatures, the integrity and reliability of the self-storage rating values are preserved. On the other hand, based on the self-storage rating values and our reputation value computing algorithm, one step is enough to rate or obtain the whole positive rating values of a peer without other participants or broadcasting messages. Extensive simulations have been conducted to evaluate the performance of our system. Simulation results show that the message overhead of our system is reduced significantly (4 messages for each transaction) compared with existing self-storage P2P reputation systems, which makes our system a scalable reputation system for handling a large number of P2P services. Our system is also robust to malicious behaviors of peers. Simulation results show that the service selection success ratio is greater than 0.8 even when there are 70% malicious peers. Moreover, when those participants are not reachable in existing self-storage P2P reputation systems, the rating values verification process fails, while in our system, no other peer is involved and this type of threat can be totally avoided.
An Improved Ant Colony Broadcasting Algorithm for Wireless Sensor Networks
Authors: Jiang Nan , Zhou Rigui , Yang Shuqun , Ding Qiulin
Published: January 2009

Recent advances in nano-technology have made it possible to develop a large variety of Micro Electro-Mechanical Systems (MEMS)-miniaturized low-power devices that integrate sensing, special-purpose computing, and wireless communications capabilities. A sensor network is a collection of many small devices, each with sensing, computation, and communication capability. It has many potential applications, such as building surveillance and environmental monitoring. Broadcasting is defined that communications between one source and all receiver in networks, and it is widely used in Wireless Sensor Networks. Therefore, how to design an efficient and scalable broadcast protocol is challenging and meaningful work.

Ant Colony Algorithm is a bionic optimization algorithm which simulated insect behavior of ants swarm intelligence. It is robust, has excellent advantages of distributed computation mechanism, and it has been widely applied to the solution of TSP, production scheduling, Graph Coloring Problem, and other combinatorial optimization problems. Broadcasting in wireless sensor networks is very similar with the ants routing problem. The target nodes and source nodes for broadcasting can be respectively compared to food and ant nests, and broadcasting problem can be regarded as the issue that ants find the optimal path between food and nests. When using ant colony algorithm for broadcasting, ants pheromone is calculated to select the path in accordance with the transition probability, and each ant in the path does not need access to all the information before starting, thus this will avoid the calculation of overhead of the initialization of parameters information in all nodes and the paths, and achieve the goal of multi-path data broadcasting in large-scale sensor networks.

In this paper, we describe the broadcasting problem in sensor networks and introduce a network model, and after considering energy efficient broadcast in such networks, combined the characteristic of Wireless Sensor Networks and the properties of ant algorithm to quickly identify an optimal path, we introduce and evaluate an improved ant colony broadcasting algorithm (IACBA), which can adaptively find the optimal broadcasting path without global network information. In our simulation, the notion of network density is introduced in order to identify classes of network topologies with similar characteristics. We mainly analyze energy depletion, minimum distance, and network lifetime, and the results show that out algorithm can reduce energy depletion dramatically and decrease communication distances in broadcasting, and our algorithms can prolong network lifetime by about 10%-20% compared with BIP, and about 30%-50% compared with flooding.
AAPP: An Anycast Based AODV Routing Protocol for Peer to Peer Services in MANET
Authors: Qi Meng , Hong Ji
Published: January 2009

The study of Peer-to-Peer (P2P) network and Mobile Ad hoc Network (MANET) are currently two hotspots in distributed domain. We propose a novel anycast based AODV routing protocol which is a simple and efficient routing protocol designed especially for MANET for P2P applications called AAPP (an Anycast based AODV routing protocol for Peer to Peer services in MANET).

AAPP integrate DHT protocol operating in a logical namespace and MANET routing protocol operating in a physical namespace. The key idea of the integration is to bring the Chord protocol to the network layer of MANETs via a one-to-one mapping between the service keys of the mobile nodes providing services and their anycast groupIDs in the namespace. The object of our design is to construct a new type of anycast based AODV model for P2P services, especially for discovery service, information administration service, file sharing service, and communication security.

It is assumed that the number of anycast groups is steady in a MANET, so we consider the instance that a node joins or leaves an anycast group. When a mobile node attains a service, such as a file and a particular data, it can share its resource to other nodes and becomes a mobile peer. Whenever a mobile node joins or leaves an anycast group, it originates a request packet and sends it to the network layer. The anycast groupID is updated correspondingly, and broadcasts the information about updating information.

In this paper, we have designed an anycast based protocol for P2P application in mobile wireless ad hoc networks based on on-demand routing protocols AODV. We have tested the packets' delivery fraction, average end-to end delay of data packets, and normalized the routing protocol performance of anycast protocols by simulation with OPNET on different traffic models, node mobility models, and connection models.

With our novel anycast protocol AAPP, the traffic load can be balanced thus, reducing the transmission delay and increase the route utilization which is better for P2P application. That all the members in one anycast group share one anycast address enables them to take the same priority in the routing searching process. Therefore, this approach can provide the transmission path with the shortest length. With scattering of the anycast server in the geographical area, the traffic load is obviously distributed in the network. All these properties can help to improve the performance of the network.
Network Anomaly Detection Based on Wavelet Fuzzy Neural Network with Modified QPSO
Authors: Ma Ruhui , Liu Yuan , Lin Xing
Published: January 2009

This paper proposes a novel network anomaly detection method employing wavelet fuzzy neural network (WFNN) to use modified Quantum-Behaved Particle Swarm Optimization (QPSO). In this paper, wavelet transform is applied to extract fault characteristics from the anomaly state. Fuzzy theory and neural network are employed to fuzzify the extracted information. Wavelet is then integrated with fuzzy neural network to form the wavelet fuzzy neural network (WFNN). The Quantum-Behaved Particle Swarm Optimization proposed by Jun Sun, which outperforms the other optimization algorithm considerably on its simple architecture and fast convergence, has previously applied to solve the optimum problem. However, the QPSO also has its own shortcomings. In QPSO if a particle flew off the boundary (the search area), the algorithm usually would regard the position value of the particle as the value of the boundary. If the boundary is at the position of local optimum, the particles were trapped into local optimum easily. It is impossible for them to arrive at the global optimum. With the increase of particle, the diversity of swam would be declined and the global search quality of the algorithm would be also declined. In the modified algorithm, it shows that the particles field off the boundary were distributed in the c∗r and () search space. The diversity of swam and the global search quality would be enhanced. So there exists a modified QPSO which is employed to train WFNN in this paper. We have demonstrated performance comparisons to QPSO-WFNN, PSO-WFNN using the same data set extracts from the KDD99 Datasets, and the results have shown that the MQPSO-WFNN model exhibits superior performance with a higher attack detection rate and lower false positive rate. Experiments with KDD Cup 1999 connection traffic data have shown that this model is able to effectively detect intrusive behaviors. It also shows the remarkable ability of our IDS to detect new type of attacks.
A Distributed Overlay Multicast Tree Reconstruction Algorithm for Live Streaming Media Applications
Authors: Jin Shan , Xia Qin , Liu Lin-Feng , Li Yi-Zhong
Published: January 2009

Recently overlay multicast has become one of the hot issues on multicast research, as it is more flexible than IP multicast and can facilitate application-specific optimization. However, the intermediate nodes in overlay multicast are easier to be faulted compared to those in IP multicast. So it is significant to design an efficient topology maintenance algorithm in overlay multicast, especially for the live streaming media applications. In this paper, the degree and delay constrained topology maintenance problem is studied, and a novel distributed multicast tree reconstruction algorithm called LOcal Topology maintenance Algorithm (LOTA) is proposed. By adopting the active strategy and avoiding package duplicates, LOTA triggers nodes pre-calculate a backup parent periodically before the multicast tree splits rather than letting downstream nodes find a new parent after a node's departure. When a node which is neither root nor leaf is gone, all its children can interact with their respective backup parents to restore the tree immediately in order to enhance the reconstruction performance and save the system maintenance cost effectively. The results of simulation and experiment show that, in both the small-scale and the large-scale group, LOTA's efficiency of tree reconstruction is much higher than the passive strategies, and its control overhead is comparatively low. Therefore, the algorithm is quite suitable for the real-time streaming media applications.
A QoS Driven Web Service Composition Method Based on ESGA (Elitist Selection Genetic Algorithm) with an Improved Initial Population Selection Strategy
Authors: Dong Shuanyu , Dong Weiqing
Published: January 2009

With more and more web services being applied, the quality of service (QoS) becomes an important criterion in a service selection. We propose a UDDI process with QoS extension to support quality requests. Service providers can send functional and QoS information to the UDDI registry. As a component of the UDDI registry, the QoS calculator calculates the QoS value of each service to decide the optimal service and send the information back to the UDDI registry. After receiving the requestor's feedback, the QoS calculator re-calculates QoS of the service.

In a service composition, component services and the composed service should satisfy local and global restrictions respectively. The QoS of component services aggregate to QoS of the composed service according to an aggregation rule. The QoS parameters may conflict with each other, so this problem is actually a multi-objective optimization. A service selection can be seen as a path formation and each node of the path is a service class.

A genetic algorithm can be used to solve complicated global optimization problems. It is proved that a simplex genetic algorithm cannot converge to optimal global solution but the elitist selection genetic algorithm (ESGA) can. So we use ESGA to solve this problem. We use integer encoding as the encoding rule. A composed service can be seen as a chromosome and a gene is an integer that represents a service number in its service class. We use an initial population selection strategy instead of the random initial population creation method. In the strategy, if the fitness of a new composed service is worse than the average fitness of the selected composed services, it should be abandoned, otherwise it should be kept. We coordinate these objectives by assigning a weight to each parameter and the fitness function is the weighted sum of QoS parameters. In the stage of genetic operation, the penalty function is subtracted from the fitness of the composed service if it does not satisfy the restrictions. We use the roulette wheel selection method, single point crossover operator, and uniform mutation operator as genetic operators.

It is shown that this method has better performance than the method using ESGA through an experiment.
Secure and Anonymous Source Routing Protocol for Wireless Ad Hoc Networks
Authors: Xu Li , Chen Sisheng
Published: January 2009

Wireless ad hoc network is formed by a group of mobile hosts that communicate through radio transmissions. In the hostile environment, this kind of network is vulnerable to traffic analysis which allows the adversary to trace the routing messages and the sensitive data packets. So, anonymous routing protocol for ad hoc networks is an important thing and has attracted more and more attention recently.

In this paper, we propose a novel, secure, and anonymous source routing, called SADSR (Secure and Anonymous Dynamic Source Routing) based on DSR. During the routing request of the SADSR, in order to hide the identity, the source node uses its current pseudonym to sponsor the routing request. And it uses the hash value of the changing share key between the source and destination as the tag of the destination. Meanwhile, it employs an initialized Bloom Filter as the routing record table to record the route. When the intermediate nodes receive the routing request, it randomly chooses a secret key and adds its identity into the Bloom Filter with seeding the secret key. So, when the destination node receives the routing request, the Bloom Filter has recorded the route information. Because the feature of the pseudonym employed in our scheme, the destination node can authenticate the source node and updates their share secret key when it replies to the routing request. During the routing reply phase, the intermediate node can determine whether it is the router by checking the Bloom Filter in the reply packet. The router applies the pseudonym based signature to protect the message during the routing reply phase, which makes sure that the neighborhood node en route can authenticate the upstream node and does not disclose its identity. SADSR also contains the routing maintenance and secure anonymous data transmission which are separately used by the end-to-end validate mechanism and HMAC strategy.

The performance of security and anonymity of SADSR is analyzed by both in theory and simulation. Compared to the other anonymous routing protocols, SADSR is not only an anonymous routing protocol, but also a secure one. It can provide authentication and integrity, anonymous neighborhood, identity anonymity, and route anonymity. The simulation results using NS-2 indicate that though SADSR is a secure and anonymous routing protocol, but the efficiency of SADSR is close to the secure routing protocol SDSR and anonymous routing protocol AnonDSR.
Efficient Data Transmitting Model in Wireless Sensor Networks
Authors: Wang Tian , Dong Weiqing , Wu Lin
Published: January 2009

Considering the high similarity among sensor data sequences in wireless sensor networks(WSNs), we propose an efficient data transmitting model—EDTM, which optimizes the data collection scheme utilizing the correlation among sensor nodes. The aim of EDTM is to extend the lifetime of the sensor networks as much as possible, meanwhile guaranteeing the accuracy of data provided to the user which is measured by two parameters, error bounds and confidence.

To realize this purpose, EDTM exploits the matching relationship, and if some nodes are matching with each other to a certain degree, it selects the optimal representative nodes Vs to undertake the transportation task. Thus, the measurements of some nodes can be substituted and the energy is conserved. A challenge of the matching algorithm is the time drifting and data lost problem. To obtain the real variation curves of sense attribute, we piecewise fit data sequences using least squares and the fitting error is eliminated in the matching estimation. EDTM computes a parameter IDST based on the sensing curves and we prove that according to the IDST we could analyze the matching degree of any two nodes. At the end, the sensor nodes are distributed into matching sets. We also design the optimal representative node selection scheme including three phases. Every node in the matching sets need to send a cmsg packet to sink in order to inform sink its energy cost information. Sink computes each node's parameter L, which reflects the energy consumption and the influence of energy balance of the node, selects Vs, and informs the transmitting node Vs by sending a tmsg packet.

In order to test our approach, an experimental simulation has been done over real-world data and the performance of EDTM has been analyzed. The outcome demonstrates the low error ratio of EDTM, and its effectiveness in decreasing the energy cost.