Minimizing energy consumption of data centers is important to reduce carbon emissions. Virtual machines (VMs) consolidation is a typical technique to utilize the available data center resources and thus improve energy efficiency. The cooling systems consume up to 50% of the total data center electricity. In this work, we investigate the joint energy optimization of cooling systems and VM consolidations in cloud data centers. We propose a cooling-aware VM consolidation (CAVC for short) algorithm to the problem. The CAVC algorithm is a two-stage solution: 1) we first relax the constraints of the problem and determine an optimal number of physical machines (PMs) and an optimal CPU utilization of the PMs that yields the minimum cooling power; and 2) based on the initial solution of the first stage, we consolidate the VMs into the predetermined PMs with the predetermined CPU utilization ratio as much as possible. To the best of authors’ knowledge, this is the first work that jointly considers the VM consolidation and the cooling systems in minimizing energy consumption of cloud data centers. We derive an approximation ratio of CAVC over the optimal solution. The real-world data set (i.e., Google cluster data) is adopted in the simulations and the results show that the CAVC algorithm yields very close energy consumption to the theoretical lower bound.

This paper proposed an efficient omnidirectional surveillance system for i-habitat (intelligent habitat or smart home in another name) security. In this surveillance system, the omnidirectional scenes in a room, kitchen, balcony, dining hall, corridor, garage or backyard within an i-habitat are first captured using wireless webcam attached to a specially designed hyperbolic optical mirror. The captured scenes are then fed into a wireless router connected to laptop computer for image processing and alarm purposes. A mapping algorithm is developed to match the captured omnidirectional image into panoramic image, hence providing the observer or image processing tools a complete wide angle of view. An efficient trespasser detection algorithm is designed for trespasser detection purpose, and an efficient faint detection algorithm is designed to identify/monitor if there is any member who stay in i-habitat (old-folks or ill-patients) who fall down or faint and thus, immediate attention can be carried out. Based on the experimental findings, both the proposed trespasser and faint detection algorithm achieves high accuracy.

We address security issues in a cloud database system which employs the DBaaS model --- a data owner (DO) exports data to a cloud database service provider (SP). To provide data security, sensitive data is encrypted by the DO before it is uploaded to the SP. Compared to existing secure query processing systems like CryptDB [7] and MONOMI [8], in which data operations (e.g., comparison or addition) are supported by specialized encryption schemes, our demo system, SDB, is implemented based on a set of data-interoperable secure operators, i.e., the output of an operator can be used as input of another operator. As a result, SDB can support a wide range of complex queries (e.g., all TPC-H queries) efficiently. In this demonstration, we show how our SDB prototype supports secure query processing on complex workload like TPC-H. We also demonstrate how our system protects sensitive information from malicious attackers.

We address security issues in a cloud database system which employs the DBaaS model. In such a model, a data owner (DO) exports its data to a cloud database service provider (SP). To provide data security, sensitive data is encrypted by the DO before it is uploaded to the SP. Existing encryption schemes, however, are only partially homomorphic in the sense that each of them was designed to allow one specific type of computation to be done on encrypted data. These existing schemes cannot be integrated to answer real practical queries that involve operations of different kinds. We propose and analyze a secure query processing system (SDB) on relational tables and a set of elementary operators on encrypted data that allow data interoperability, which allows a wide range of SQL queries to be processed by the SP on encrypted information. We prove that our encryption scheme is secure against two types of threats and that it is practically efficient.

Peer Data Management Systems (PDMS) are an attractive solution for managing distributed heterogeneous information. When a peer (client) requests data from another peer (server) with a different schema, translations of the query and its answer are done by a sequence of intermediate peers (translators). There are two privacy issues in this P2P data integration process: (i) answer privacy: no unauthorized parties (including the translators) should learn the query result; (ii) mapping privacy: the schema and the value mappings used by the translators to perform the translation should not be revealed to other peers. Elmeleegy and Ouzzani proposed the PPP protocol that is the first to support privacy-preserving querying in PDMS. However, PPP suffers from several shortcomings. First, PPP does not satisfy the requirement of answer privacy, because it is based on commutative encryption; we show that this issue can be fixed by adopting another cryptographic technique called oblivious transfer. Second, PPP adopts a weaker notion for mapping privacy, which allows the client peer to observe certain mappings done by translators. In this paper, we develop a lightweight protocol, which satisfies mapping privacy and extend it to a more complex one that facilitates parallel translation by peers. Furthermore, we consider a stronger adversary model where there may be collusions among peers and propose an efficient protocol that guards against collusions. We conduct an experimental study on the performance of the proposed protocols using both real and synthetic data. The results show that the proposed protocols not only achieve a better privacy guarantee than PPP, but they are also more efficient.

Most previous research on privacy-preserving data publishing, based on the k-anonymity model, has followed the simplistic approach of homogeneously giving the same generalized value in all quasi-identifiers within a partition. We observe that the anonymization error can be reduced if we follow a non-homogeneous generalization approach for groups of size larger than k. Such an approach would allow tuples within a partition to take different generalized quasi-identifier values. Anonymization following this model is not trivial, as its direct application can easily violate k-anonymity. In addition, non-homogeneous generalization allows for additional types of attack, which should be considered in the process. We provide a methodology for verifying whether a non-homogeneous generalization violates k-anonymity. Then, we propose a technique that generates a non-homogeneous generalization for a partition and show that its result satisfies k-anonymity, however by straightforwardly applying it, privacy can be compromised if the attacker knows the anonymization algorithm. Based on this, we propose a randomization method that prevents this type of attack and show that k-anonymity is not compromised by it. Nonhomogeneous generalization can be used on top of any existing partitioning approach to improve its utility. In addition, we show that a new partitioning technique tailored for non-homogeneous generalization can further improve quality. A thorough experimental evaluation demonstrates that our methodology greatly improves the utility of anonymized data in practice.

Service providers like Google and Amazon are moving into the SaaS (Software as a Service) business. They turn their huge infrastructure into a cloud-computing environment and aggressively recruit businesses to run applications on their platforms. To enforce security and privacy on such a service model, we need to protect the data running on the platform. Unfortunately, traditional encryption methods that aim at providing "unbreakable" protection are often not adequate because they do not support the execution of applications such as database queries on the encrypted data. In this paper we discuss the general problem of secure computation on an encrypted database and propose a SCONEDB Secure Computation ON an Encrypted DataBase) model, which captures the execution and security requirements. As a case study, we focus on the problem of k-nearest neighbor (kNN) computation on an encrypted database. We develop a new asymmetric scalar-product-preserving encryption (ASPE) that preserves a special type of scalar product. We use APSE to construct two secure schemes that support kNN computation on encrypted data; each of these schemes is shown to resist practical attacks of a different background knowledge level, at a different overhead cost. Extensive performance studies are carried out to evaluate the overhead and the efficiency of the schemes.

Finding frequent itemsets is the most costly task in association rule mining. Outsourcing this task to a service provider brings several benefits to the data owner such as cost relief and a less commitment to storage and computational resources. Mining results, however, can be corrupted if the service provider (i) is honest but makes mistakes in the mining process, or (ii) is lazy and reduces costly computation, returning incomplete results, or (iii) is malicious and contaminates the mining results. We address the integrity issue in the outsourcing process, i.e., how the data owner verifies the correctness of the mining results. For this purpose, we propose and develop an audit environment , which consists of a database transformation method and a result verification method. The main component of our audit environment is an artificial itemset planting (AIP) technique. We provide a theoretical foundation on our technique by proving its appropriateness and showing probabilistic guarantees about the correctness of the verification process. Through analytical and experimental studies, we show that our technique is both effective and efficient.

Fuzzy adaptive equalizer (FAE) is a knowledge based equalizer operating on linguistic variables. The advantages of using fuzzy logic adaptation scheme with respect to more traditional adaptation schemes in powerline communication system are the simplicity of the approach and the use of knowledge (fuzzy IFTHEN rules and input output pairs information) about the communication medium. This paper presents a new adaptive blind equalization method based on fuzzy logic for powerline channel. We introduce a new type of fuzzy adaptive blind equalizer (FABE) using extended Kalman filter (EKF) based adaptation algorithm for powerline channel equalization. The proposed blind equalizer for powerline channel has the following merits: It is new and simple in design, and it does not requires training sequence. In a changeable distorted powerline channel, data transmission is continuous and do not stop for training the equalizer. The performance of EKF-based FABE is compared with two other types of FABEs based on the recursive least squares (RLS) and the least mean squares (LMS) adaptation algorithm. The simulation results show that EKF-based FABE has faster convergent and lower steady state probability of error compared to the other two FABEs. The bit error rate (BER) of the EKF-based FABE is close to that of the optimal equalizer.