Meeting the challenge of a peer-to-peer network: An SNA management services infrastructure for APPN

Systems Network Architecture (SNA) is no longer a strictly hierarchical networking environment. The introduction of advanced peer-to-peer networking (APPN) provides for more flexibility: end user systems attaching to an SNA network are no longer controlled by a mainframe host. This new flexibility creates challenges for SNA/Management Services (SNA/MS), however, since the previous hierarchical relationship provided a vehicle for network management as well as network control. The SNA/MS architecture has been extended to meet the needs of this peer-to-peer environment, providing a management infrastructure which replaces the previous SSCP to PU relationship, and at the same time provides for much greater flexibility. This new infrastructure provides a mechanism for negotiating manager and agent (referred to as focal point and entry point in SNA/MS) roles between systems, and a transport technique for management services data which exploits advanced program-to-program communication (APPC).     

An optimal and secure resource searching algorithm for unstructured mobile peer-to-peer network using particle swarm optimization

Applied Intelligence - The outrageous demand for file sharing among peers has become a significant development of the Peer-to-Peer (P2P) communication system during the past few years. The essence...     

OntoZilla: An ontology-based, semi-structured, and evolutionary peer-to-peer network for information systems and services

We present a system called “OntoZilla”, which combines ontologies and peer-to-peer (P2P) technology, with a vision of improving the information search process and facilitating greater integration as well as interoperability. In OntoZilla, peers supporting the same concept are grouped into the same cluster, and the relationships between clusters are modeled according to the concepts they specialize in. Therefore, a query belonging to a specific concept can be routed to the suitable group of peers in a systematic way, thus supporting efficient concept search. Moreover, since peer relationships are based on peers’ expertises which may change over time, our semi-structured system can flexibly cope with the changing environment as peers evolve.     

PeerTrust: supporting reputation-based trust for peer-to-peer electronic communities

Peer-to-peer (P2P) online communities are commonly perceived as an environment offering both opportunities and threats. One way to minimize threats in such communities is to use community-based reputations to help estimate the trustworthiness of peers. We present PeerTrust - a reputation-based trust supporting framework, which includes a coherent adaptive trust model for quantifying and comparing the trustworthiness of peers based on a transaction-based feedback system, and a decentralized implementation of such a model over a structured P2P network. PeerTrust model has two main features. First, we introduce three basic trust parameters and two adaptive factors in computing trustworthiness of peers, namely, feedback a peer receives from other peers, the total number of transactions a peer performs, the credibility of the feedback sources, transaction context factor, and the community context factor. Second, we define a general trust metric to combine these parameters. Other contributions of the paper include strategies used for implementing the trust model in a decentralized P2P environment, evaluation mechanisms to validate the effectiveness and cost of PeerTrust model, and a set of experiments that show the feasibility and benefit of our approach.     

基于询问-应答策略的Gnutella资源搜索算法的改进

资源搜索是P2P网络的关键问题.介绍了Cmutella网络资源搜索路由机制,分析了Gnutella网络的现有改进算法及其存在的问题,针对这些问题,提出了一种基于询问-应答策略的网络资源搜索路由机制的改进策略,在不影响搜索效率的情况下,能减少大量的冗余信息和有效地提高可扩展性,并且还具有自适应性.     

Reusing ontology mappings for query routing in semantic peer-to-peer environment

To efficiently support automated interoperability between ontology-based information systems in distributed environments, the semantic heterogeneity problem has to be dealt with. To do so, traditional approaches have acquired and employed explicit mappings between the corresponding ontologies. Usually these mappings can be only obtained from human domain experts. However, it is too expensive and time-consuming to collect all possible mapping results on distributed information systems. More seriously, as the number of systems in a large-scale peer-to-peer (P2P) network increases, the efficiency of the ontology mapping is exponentially decreased. Thereby, in this paper, we propose a novel semantic P2P system, which is capable of (i) sharing and exchanging existing mappings among peers, and (ii) composing shared mappings to build a certain path between two systems. Given two arbitrary peers (i.e., source and destination), the proposed system can provide indirect ontology mappings to make them interoperable. In particular, we have focused on query-based communication for evaluating the proposed ontology mapping composition system. Once direct ontology mappings are collected from candidate peers, a given query can be (i) segmented into a set of sub-queries, and (ii) transformed to another query. With respect to the precision performance, our experimentation has shown an improvement of about 42.5% compared to the keyword-based query searching method.     

改进的非结构化P2P网络搜索算法

如何高效地搜索资源是P2P网络中最为关键的问题.非结构化的对等网络,一般以广播方式作为其搜索的基本策略,引发较大的网络流量.针对以上问题,提出了一种利用节点积累的经验指导节点传播查询的路由搜索算法.在该算法中,通过记录节点关注的主题、主题的信息量大小和满足主题的目标节点,并建立对应关系表.当节点收到查询后,就利用该表来指导节点选择查询,以便更快地找到查询结果.仿真结果表明,该算法有效地减少了查询带来的网络流量,提高了查找的成功率.     

An efficient Nash-implementation mechanism for network resource allocation

We propose a mechanism for auctioning bundles of multiple divisible goods in a network where buyers want the same amount of bandwidth on each link in their route. Buyers can specify multiple routes (corresponding to a source-destination pair). The total flow can then be split among these multiple routes. We first propose a one-sided VCG-type mechanism. Players do not report a full valuation function but only a two-dimensional bid signal: the maximum quantity that they want and the per-unit price they are willing to pay. The proposed mechanism is a weak Nash implementation, i.e., it has a non-unique Nash equilibrium that implements the social-welfare maximizing allocation. We show the existence of an efficient Nash equilibrium in the corresponding auction game, though there may exist other Nash equilibria that are not efficient. We then generalize this to arbitrary bundles of various goods. Each buyer submits a bid separately for each good but their utility function is a general function of allocations of bundles of various divisible goods. We then present a double-sided auction mechanism for multiple divisible goods. We show that there exists a Nash equilibrium of this auction game which yields the efficient allocation with strong budget balance.     

I-Swifter: Improving chunked network coding for peer-to-peer content distribution

Network coding has been proposed as a promising approach for peer-to-peer content distribution in recent literature. Not only reducing the average download time, but also improving resilience to peer churn has been showed as the benefits brought by network coding. State-of-the-art network coding content distribution systems perform network coding within segments or chunks, in order to reduce computational overhead. In our previous work (Xu et al. 2008), we proposed to schedule segment requests at a local-rarest-first basic. Local-rarest-first segment scheduling, as we demonstrated, is superior to the random scheduling. In this paper, we make a further step towards improving chunked network coding content distribution systems. We propose a requests reducer that reduces the overhead in control traffic and an encoding vectors reducer that eliminates the transmission of encoding vectors. Our contributions are to save unnecessary requests from downstream peers, and to reduce encoding vectors payload when the upstream peer owns the complete requested segment. This paper presents a realistic implementation, named I-Swifter. And we also make a comparative study on various related implementations. Experimental results show that there is about 10–20% of encoding vectors can be saved in I-Swifter. Moreover, I-Swifter improves average and maximum download time, the server load as well.     

CGNet: cross-guidance network for semantic segmentation

Semantic segmentation is a fundamental task in image analysis.The issue of semantic segmentation is to extract discriminative features for distinguishing differ...     

Advanced learning resource management system with ontology-based hierarchy semantic model

The requirement for advanced learning resource management system is a hot topic in e-learning, which should support sharing, reusability and interoperability of learning resource. The development of semantic technology has provided opportunities to solve the problems. In e-learning area, there have been many research efforts in this direction. However, such kinds of existing systems have many weaknesses on resources usability and system availability because of various requirements on learning resources sharing, and the complexity of semantic technology itself. This paper proposes a feasible architecture for constructing learning resource sharing system with high availability through adopting semantic technology, and ontology-based hierarchy semantic model and method to construct course ontology are proposed. The approach has been validated with prototype development.     

AMPN: a semantic resource for Arabic morphological patterns

In this paper, we present a pilot Arabic morphological Pattern Net study based on a lexical semantic resource. During this study, a limited number of Arabic Morphological Patterns have been selected in order to analyze the structure and the behavior of the verbs in the Arabic PropBank, which is a semantically annotated corpus of newswire text from the Annahar Journal. Our goal is twofold: (a) to study whether there is a direct relationship between morphological patterns and verbal semantic roles; and, (b) to verify that this direct relationship is a pervasive component of Arabic verb morphology. The approach to building our morphological Patterns database is based on linguistic generalization of the semantic roles of the verbal predicates. The results obtained show promising outcome for a future, more comprehensive study.     

Using peer-to-peer technology for knowledge sharing in communities of practices

Communities of Practices (CoPs) are informal structures within organizations that bind people together through informal relationships and the sharing of expertise and experience. As such, they are effective tools for the creation and sharing of organizational knowledge, and an increasing number of organizations are adopting them as part of their knowledge management strategies. In this paper, we examine the knowledge sharing characteristics and roles of CoPs and develop a peer-to-peer knowledge sharing architecture that matches the behavioral characteristics of the members of the CoPs. We also propose a peer-to-peer knowledge sharing tool called KTella that enables a community's members to voluntarily share and retrieve knowledge more effectively.     

A mechanism for resource pricing and fairness in peer-to-peer networks

In peer-to-peer (P2P) networks, each peer acts as the role of client and server. As a client, each peer is regarded as a service customer. It sends requests to other peers to download files and obtains resource allocation from them. As a server, each peer is thought as a service provider. It receives service requests from other peers and allocates its resources to them. To encourage cooperation between peers, fairness is very important in P2P networks since it fosters an incentive to the peers to offer resources to the network. We formulate a fair resource allocation model for P2P networks and investigate the utility optimization problem by Lagrangian method. In order to realize the optimal resource allocation, we present a novel price-based resource allocation scheme by applying the first order Lagrangian method and low-pass filtering scheme, so that a service provider can allocate its resources to its customers based on offered prices, achieving the efficient and fair allocation of the available resources to the serviced customers. Simulation results confirm that the proposed algorithm can achieve the optimum within reasonable convergence times.     

Reputation management algorithms for DHT-based peer-to-peer environment

This paper addresses the problem of integration of reputation management mechanisms into data look-up and routing processes to cope with some specific security problems in peer-to-peer (P2P) networks based on Distributed Hash Tables (DHT). The goal is to find a mode for “good” peers to cooperate in order to withstand malicious activity of single malevolent peers and their collusions as well.We start from consideration of individual instruments for reputation evaluation that every single peer should be provided with to autonomously define the level of its own trust towards others. We also propose a possible scenario of integration of some existing reputation management techniques and routing mechanisms in a P2P network based on the popular Kademlia algorithm. Then, we present an interaction algorithm that allows peers to obtain the global trust value for each single node through exchanging opinions in the form of local trust values independently calculated by every peer with other members of the community. Such collaboration between peers is indispensable to cope with malicious activity of inconsistent nature specific to DHT-based environment. To render the algorithm resilient to the presence of malicious participants we propose to apply solutions for Byzantine Agreement to exchange opinions among peers. We also provide mathematical evaluations concerning the complexity and computational costs of the proposed algorithm that evidence apparent improvements over the previous one.     

L-overlay: A layered data management scheme for peer-to-peer computing

Efficient storage and handling of data stored in a peer-to-peer (P2P) network, proves vital for various applications such as query processing and data mining. This paper presents a distributed, scalable and robust layered overlay (L-overlay) to index and manage multidimensional data in a dynamic P2P network. The proposed method distinguishes between the data and peer layers, with efficient mapping between the two. The data is organized such that semantically similar data objects are accessed hastily. Grid and tree structures are proposed for the peer layer. As application examples of L-overlay in query processing and data mining, k-nearest neighbors query processing and distributed Naïve Bayes classification algorithms, are proposed. We show the effectiveness of our scheme in static and dynamic environments using simulation. L-overlay is shown to be more efficient than SSW, an available semantic overly, in terms of maintenance and query processing costs.     

Fair and distributed peer-to-peer allocation of a common, refillable resource

We consider the general problem of distributed and fair peer-to-peer (P2P) allocation of a common, refillable resource. This problem recurs in a number of scenarios, for example grid computing, content distribution, Internet Service Provider service sharing, and distributed file storage over asymmetric channels. We present several distributed schemes for this allocation problem and show that these schemes guarantee two key properties: (i) asymptotic fairness, in that (even maliciously colluding) users are proportionally assigned resources corresponding to what they contribute; (ii) natural incentive to join and cooperate fairly in the system. We demonstrate the practicability of our approaches on a prototype P2P file storage system designed for typical residential Internet connections, in which download capacities often significantly exceed upload capacities. Our implementation shares file data when communications are idle using random linear codes so that, when needed, an end-user can download a file from several sources at a higher data rate than his home computer’s upload capacity. We present experimental results that support our analytical guarantees.     

认知无线网络的改进资源管理算法研究

提出了一种基于资源认知信道的接入算法,可用于认知无线电环境下的无线资源管理。对资源认知信道上传输的每个分组——数据域部分采用了基于联合检测的扩频码,而控制域部分则分别采用了5种不同的信道接入协议。分析并仿真了认知用户在资源认知信道上的成功接入概率以及吞吐量性能。     

Emergent standard of knowledge management: Hybrid peer-to-peer knowledge management

Knowledge has been a critical resource for supporting business strategies. The major obstacle to classical knowledge management approach is that knowledge workers hesitate to release their own control and give up sharing autonomy. The peer-to-peer architecture facilitates achieving autonomy and self-organized management. However, there are still some problems, such as computational efficiency, organizational memory accumulation. This study proposes a hybrid peer-to-peer architecture to consider the tradeoff between centralized and decentralized knowledge management. The proposed architecture preserves the autonomy of knowledge workers as well as allows the accumulation of organizational memory. It also encourages workers to issue on-line discussions to add knowledge annotations. Under this architecture, a scenario of collaborative product design is described.