This special issue is partly associated with the 2009 International Work Shop on Information Security and Applications (IWISA 2009), which was held in Qingdao, China in November 2009.While some other manuscripts are solicited from the authors who are not participants of the conference. The purpose of this special issue is to provide a fast publication of extended versions of the high-quality conference papers on network or related to network and also the papers from authors with original high-quality contributions that have neither been published in nor submitted to any journals or refereed conferences. Papers are mainly interdisciplinary research in network related theory and network related techniques to unsolved problems, such as algorithm for in-network query processing, neural network algorithm, and fuzzy clustering algorithm for Ad Hoc Network etc. We received 23 papers from around the world and selected 10 to be included in the special issue after a thorough and rigorous review process. The presented papers are mainly devoted to discussion on algorithms in networks or using network related algorithms to solve problems in other area.In “BF-k: a near-optimal operator placement algorithm for in-network query processing”, Dr. Junhu Zhang proposes a kind of decentralized and adaptive operator placement algorithm BF-k, which reduces greatly the time complexity of a near optimal placement of a large number of relational operators for an in-network query processing. The performance of BFk is also explored in this paper.In “Fuzzy Clustering Algorithm Based on the Time and Surplus Energy Constrain for Ad Hoc Network”, Daoquan Li, et al, proposes a fuzzy Clustering algorithm based on the time and surplus energy constrain in Ad Hoc network. It defines the fuzzy rules of node’s TTL(time-to-live) and the node surplus energy. It also carries on the fuzzy reasoning, the clustering question is generalized to the question of finding an maximum Independent Set. In “The Estimation of Trustworthy of Grid Services Based on Neural Network”, Zhengli Zhai et al present Estimating trustworthy of Grid Services with the method of Neural Network from the aspect of trustworthy history sequence. The principle of the method, applicable Neural Network structure, Neural Network constructing, input standardization, training sample constructing, and the procedure of estimating trustworthy of Grid Services with trained Neural Network are presented. Experiments confirm that the methods with Neural Network are feasible and effective to estimate trustworthy of Grid Service.In “XPath Query Completeness Verification Algorithms in DAS”, Xiaoyuan Bao et al present propose an algorithm which provides an authentication method for the query results returned from a possible malicious server on which database is outsourced and query is evaluated. The basic idea is to build some Merkle hash trees twice to verify the correctness and completeness of the query results.In “Active Diverse Learning Neural Network Ensemble Approach for Power Transformer Fault Diagnosis”, Yu Xu et al propose An ensemble learning algorithm by analyzing the error function of neural network ensembles, by which, individual neural networks were actively guided to learn diversity. Experiment results show that the algorithm has higher accuracy than IEC method and BP network. In addition, the performance is more stable than conventional ensemble method, i.e., Bagging and Boosting.In “A Data Gathering Algorithm Based on Mobile Agent and Emergent Event-Driven in Cluster-Based WSN”, Lingyun Yuan et al propose a new data gathering algorithm for cluster-based wireless sensor network based on mobile agent and event-driven The process of dynamically clustering the sensor nodes is based on the event severity degree, by which the scale and lifetime of clusters are determined..In “An Efficient Algorithm for Reverse 2-median Problem on A Cycle”, Qin Wang et al consider the R2MC problem, and transform the R2MC problem to a reverse 3-median problem on a path and show that this problem can be solved efficiently by strongly polynomial algorithm.In “Empirical Analysis of Customer Behaviors in Chinese E-Commerce”, Jinlong Wang et al presents an empirical analysis on the sale transactions from the 360buy website based on the analysis of time interval distributions in perspectives of customers. Results reveal that in most situations the time intervals approximately obey the power-law distribution over two orders of magnitudes. Additionally, time interval on customer’s successive purchase can reflect how loyal a customer is to a specific product category.In “A Reflective NetGAP Design and its Session Mechanism Realization based on Agent”, Yu Songsen et al propose a network isolation system model based on Reflective architecture. The Reflective GAP is hardware-based and its purpose is to rapidly mirror buffers between the Non-Trusted memory and the trusted memory.In “Optimizing of SVM with Hybrid PSO and Genetic Algorithm in Power Load Forecasting”, Yongli Wang et al propose Hybrid Particle Swarm Optimization (HPSO) with genetic algorithm(GA) mutation to optimize the SVM forecasting model.. The PSOGA-SVM method proposed in this paper is based on the global optimization of PSOGA and local accurate searching of SVM.Hopefully, this Special Issue will contribute to enhancing knowledge in many diverse areas of the network and some network related area. The author wishes to extend his thanks to Dr. Xijun Zhu who have done a lot of work in soliciting papers to this special issue, and to all those who kindly participated as peer reviewers. Their involvement was greatly appreciated. We also thank Mr. George J. Sun, the Executive Editor-in-Chief of JNW for his continued encouragement, guidance and support in the preparation of this issue.