In this paper, we introduce a pack-centric approach to data center resource management by abstracting a system as a pack of resources and considering the mapping of these packs onto physical data center resource groups, called swads. The assignment of packs/VMs to swads/PMs is formulated as an integer optimization problem that can capture constraints related to the available resources, data center efficiency and customers' complex requirements. Scalability is achieved through a hierarchical decomposition method. We illustrate aspects of the proposed approach by describing and experimenting with a concrete and challenging resource allocation problem.

Ye Xia;Mauricio Tsugawa;Jose A.B. Fortes;式刚 陈

2015-9-14

Radio-frequency identification (RFID) technologies have been widely used in many applications, including inventory management, supply chain, product tracking, transportation, logistics, etc. Tag estimation, which is to estimate the cardinality of a single tag set, is an important research topic. This paper expands the estimation research as follows: It performs joint estimation between two tag sets (which exist at different locations or at the same location but different times). More importantly the estimation is fine-grained in an effort to accommodate common practical scenarios, where each tag set consists of tags belonging to different categories. For any two given tag sets, we want to know the detailed information about the joint property of each category, instead of just the aggregate information of the whole sets. Furthermore, due to the open nature of RFID communications, it is often desirable that tag estimation can be performed in an anonymous way without revealing the tags' ID information. To support these requirements, we develop a new technique called mask bitmap that can encode a tag set without requiring the tags to report their IDs or category IDs. Any two mask bitmaps of different tag sets can be combined to perform category-level joint estimation. Through formal analysis, we determine how to set system parameters to meet a given accuracy requirement that can be arbitrarily set. Extensive simulation results confirm that the proposed solution can yield accurate category-level estimates in an efficient way, and preserve tags' anonymity as well.

Min Chen;Jia Liu;式刚 陈;Qingjun Xiao

2016-12-14

We propose an integrated QoS routing framework based on selective probing for high-speed packet-switching networks. The framework is fully distributed and depends only on the local state maintained at every individual node. By using controlled diffusion computations, the framework captures the common messaging and computational structure of distributed QoS routing, and allows an efficient implementation due to its simplicity. Different distributed routing algorithms (DRAs) can be quickly developed by specifying only a few well-defined constraint-dependent parameters within the framework. Our simulation shows that the overhead of the proposed algorithms is stable and modest.

式刚 陈;Klara Nahrstedt

Conference on Local Computer Networks

1998

Due to the open nature of a sensor network, it is relatively easy for an adversary to eavesdrop and trace packet movement in the network in order to capture the receiver physically. After studying the adversary's behavior patterns, we present countermeasures to this problem. We propose a locationprivacy routing protocol (LPR) that is easy to implement and provides path diversity. Combining with fake packet injection, LPR is able to minimize the traffic direction information that an adversary can retrieve from eavesdropping. By making the directions of both incoming and outgoing traffic at a sensor node uniformly distributed, the new defense system makes it very hard for an adversary to perform analysis on locally gathered information and infer the direction to which the receiver locates. We evaluate our defense system based on three criteria: delivery time, privacy protection strength, and energy cost. The simulation results show that LPR with fake packet injection is capable of providing strong protection for the receiver's location privacy. Under similar energy cost, the safe time of the receiver provided by LPR is much longer than other methods, including Phantom routing [1] and DEFP [2]. The performance of our system can be tuned through a few system parameters that determine the tradeoff between energy cost and the strength of location-privacy protection.

Ying Jian;式刚 陈;Zhan Zhang;Liang Zhang

IEEE Transactions on Wireless Communications

2008-10

Thanks to the proliferation of Internet access and modern digital and mobile devices, online survey has been flourishing into data collection of marketing, social, financial and medical studies. However, traditional data collection methods in online survey suffer from serious privacy issues. Existing privacy protection techniques are not adequate for online survey for lack of strong privacy. In this paper, we propose a practical strong privacy online survey scheme SPS based on a novel data collection technique called dual matrix masking (DM2), which guarantees the correctness of the tallying results with low computation overhead, and achieves universal verifiability, robustness and strong privacy. We also propose a more robust scheme RSPS, which incorporates multiple distributed survey managers. The RSPS scheme preserves the nice properties of SPS, and further achieves robust strong privacy against joint collusion attack. Through extensive analyses, we demonstrate our proposed schemes can be efficiently applied to online survey with accuracy and strong privacy.

You Zhou;Yian Zhou;式刚 陈;Samuel S. Wu

2017-7-13

Software-defined networking (SDN) separates the control plane from the data plane to ease network management and provide flexibility in packet routing. The control plane interacts with the data plane through an interface that configures the forwarding tables, usually including a flow table and a group table, at each switch. Due to high cost and power consumption of ternary content addressable memory, commodity switches can only support flow/group tables of limited size, which presents serious challenge for SDN to scale to large networks. One promising approach to address the scalability problem is to deploy aggregate default paths specified by wildcard forwarding rules. However, the multi-dimensional interaction among numerous system parameters and performance/scalability considerations makes the problem of setting up the flow/group tables at all switches for optimal overall layout of default paths very challenging. This paper studies the joint optimization of flow/group tables in the complex setting of large-scale SDNs. We formulate this problem as an integer linear program, and prove its NP-hardness. An efficient algorithm with bounded approximation factors is proposed to solve the problem. The properties of our algorithm are formally analyzed. We implement the proposed algorithm on an SDN test bed for experimental studies and use simulations for large-scale investigation. The experimental results and simulation results show that, under the same number of flow entries, our method can achieve better network performance than the equal cost multipath while reducing the use of group entries by about 74%. Besides, our method can reduce the link load ratio and the number of flow entries by approximately 13% and 60% compared with DevoFlow with 10% additional group entries.

Gongming Zhao;Hongli Xu;式刚 陈;刘生 黄;Pengzhan Wang

IEEE/ACM Transactions on Networking

2018-8

The Radio-Frequency Identification (RFID) technology has stimulated many innovative applications. Misplaced-tag pinpointing (MTP) is important to RFID applications in production economics because optimal inventory placement can significantly increase profit. Previous research from the database perspective needs to process a large amount of data which is time-consuming to collect (and energy-consuming if active tags are used). How to efficiently address the MTP problem from the protocol design perspective however has not been investigated. In this paper, we propose a series of protocols toward efficient MTP solution in large RFID systems. The proposed protocols detect misplaced tags based on reader positions instead of tag positions to guarantee the efficiency and scalability as system scale grows, because the number of readers is much smaller than that of tags. Considering applications to employ more and more popular active tags, we further propose a solution requiring responses from only partial tags in favor of energy saving. We analyze the optimal performances of proposed protocols to demonstrate their efficiency potential and conduct extensive simulation experiments to evaluate their performance under various scenarios. The results show that the proposed protocols can significantly increase the time efficiency and the energy efficiency by over 70% on average when compared with the state of the art.

Kai Bu;Bin Xiao;Qingjun Xiao;式刚 陈

2011

We study a spectrum auction problem where each request from new spectrum users has spatial, temporal, and spectral features. Our goal is to design truthful auction mechanisms that maximize either the overall social efficiency of new users (a.k.a buyers) or the revenue of the spectrum owner (a.k.a seller). Given that the optimal conflict-free spectrum allocation problem is NP-hard, this paper proposes a series of near-optimal auction mechanisms based on the following approximation techniques: linear programming (LP) relaxation, randomized rounding, derandomized rounding, monotone derandomization, and Lavi-Swamy method. Comparing with the prior art, we make two significant advances: First, our auction mechanisms are not only truthful but also provide theoretically-provable performance guarantee, an important feature that existing work under the same auction model does not have. Second, our auction mechanisms support both spatial and temporal spectral reuse, which makes the problem more challenging than existing work that deals with only spatial or temporal reuse. We perform extensive simulations to study the performance of the proposed mechanisms, and the simulation results corroborate our theoretical analysis.

河 黄;Yu E. Sun;Xiang Yang Li;式刚 陈;明军 肖;刘生 黄

IEEE Transactions on Mobile Computing

2015-6-1

Unstructured peer-to-peer networks have gained a lot of popularity due to their resilience to network dynamics. The core operation in such networks is to efficiently locate resources. However, existing query schemes, for example, flooding, random walks, and interest-based shortcut suffer various problems in reducing communication overhead and in shortening response time. In this paper, we study the possible problems in the existing approaches and propose a new hybrid query scheme, which mixes inter-cluster queries and intracluster queries. Specifically, the proposed scheme works by efficiently locating the clusters, sharing similar interests with intercluster queries, and then exhaustively searching the nodes in the found clusters with intracluster queries. To facilitate the scheme, we propose a clustering algorithm to cluster nodes that share similar interests, and a labeling algorithm to explicitly capture the clusters in the underlying overlays. As demonstrated by extensive simulations, our new query scheme can improve the system performance significantly by achieving a better tradeoff among communication overhead, response time, and ability to locate more resources.

Zhan Zhang;Yong Tang;式刚 陈;Ying Jian

Advances in Multimedia

2007

Radio frequency identification (RFID) technologies are poised to revolutionize retail, warehouse, and supply chain management. One of their interesting applications is to automatically detect missing tags in a large storage space, which may have to be performed frequently to catch any missing event such as theft in time. Because RFID systems typically work under low-rate channels, past research has focused on reducing execution time of a detection protocol to prevent excessively long protocol execution from interfering normal inventory operations. However, when active tags are used for a large spatial coverage, energy efficiency becomes critical in prolonging the lifetime of these battery-powered tags. Furthermore, much of the existing literature assumes that the channel between a reader and tags is reliable, which is not always true in reality because of noise/interference in the environment. Given these concerns, this paper makes three contributions. First, we propose a novel protocol design that considers both energy efficiency and time efficiency. It achieves multifold reduction in both energy cost and execution time when compared to the best existing work. Second, we reveal a fundamental energy-time tradeoff in missing-tag detection, which can be flexibly controlled through a couple of system parameters in order to achieve desirable performance. Third, we extend our protocol design to consider channel error under two different models. We find that energy/time cost will be higher in unreliable channel conditions, but the energy-time tradeoff relation persists.

Wen Luo;式刚 陈;Yan Qiao;Tao Li

IEEE/ACM Transactions on Networking

2014-8