35376903
Robust beamformer design by power minimization and its unconstrained partitioned implementation
A robust array beamformer design method by power minimization and its unconstrained partition implementation is proposed in this paper. An orthogonal blocking matrix is obtained through the proposed method. The new blocking matrix ensures that a desired look-direction response of the processor over a frequency band of interest can be closely approximated. Furthermore, if the spectrum of the target signal is known a priori, such as in microphone array application where the statistical property of speech is known, the new method may use fewer/less degree of freedom. This new method also provide a theoretical support for the derivation of the blocking matrix through array calibration. Simulation results show that the effectiveness of the proposed method.
9807820
Norm and coefficient constraints for robust adaptive beamforming
Norm-constrained and coefficient-constrained adaptive filters are often used in robust adaptive beamforming to mitigate the target-signal cancellation problem caused by DOA (direction of arrival) mismatch. The norm and coefficient constraints are usually selected numerically based on computer simulations or real-time experiments, which is not enough for theoretical analysis that requires explicit mathematical expressions. This paper analytically derives these constraints using the Taylor series expansion of the array correlation matrix. The constraints that are expressed in terms of maximal DOA mismatch agree well with the simulation results, and most importantly they are quite useful in practical beamformer design and performance analysis.
34374182
A Multi-Agent System for Personalized and Private Service in PDR
17105028
Performance and power analysis of globally asynchronous locally synchronous multiprocessor systems
This paper investigates the performance and power dissipation of globally asynchronous locally synchronous (GALS) multi-processor systems. We show that communication loops are a source of significant throughput degradation in communications links and that there is no degradation whatsoever under certain conditions for one-way links, and that it is possible to design GALS multiprocessors without this performance penalty. Independent clock domains and unbalanced computation in the GALS multiprocessor allow scaling of the clock frequency and supply voltage to achieve high energy efficiency. The synchronization overhead between independent clock domains results in a less than 1% performance reduction compared to a globally synchronous system over a number of DSP and numerical applications. Clock and voltage scaling can achieve an approximately 40% power savings with no reduction of performance. These results compare favorably with the 25% power savings and more than 10% performance reduction reported for GALS uniprocessors
16105685
A Hybrid Learning Approach for TV Program Personalization
The rapid growth of communication technologies and the invention of set-top-box (STB) and personal digital recorder (PDR) have enabled today’s television to receive and store tremendous programs. The abundance of TV programs precipitates a need for personalization tools to help people obtain programs that they really want to watch. User preference learning plays an important role in TV program personalization. In this paper, we introduce a hybrid user preference learning approach for TV program personalization. The learning architecture is designed to integrate multiple learning sources for preference learning, which are explicit input/modification, user viewing history, and user real-time feedback. Among those, learning from user viewing history and learning from user real-time feedback are described in detail. The experimental results proved that the hybrid learning approach outperforms the learning method merely adopting user real-time feedback.
6970027
A Dynamic En-Route Scheme for Filtering False Data Injection in Wireless Sensor Networks
In this paper, we propose a dynamic en-route filtering scheme for false data injection attacks in wireless sensor networks. In sensor networks, adversaries can inject false data reports containing bogus sensor readings or nonexistent events from compromised nodes. Such attacks may not only cause false alarms, but also drain out the limited energy of sensor nodes. Several existing schemes for filtering false reports either cannot deal with dynamic topology of sensor networks or have limited filtering capacity. In our scheme, a legitimate report is endorsed by multiple sensing nodes using their own authentication keys generated from one-way hash chains. Cluster head uses Hill Climbing approach to disseminate the authentication keys of sensing nodes to the forwarding nodes along multiple paths toward the base station. Hill Climbing guarantees that the forwarding nodes closer to a cluster hold more authentication keys for the cluster than those nodes farther from it do, hence, the number of keys held by each forwarding node can be balanced. In filtering phase, each forwarding node validates the authenticity of the reports and drops those false ones. Compared to existing schemes, our scheme can better deal with dynamic topology of sensor networks. Analytical and simulation results show that our scheme drops false reports earlier even with a lower memory requirement and tolerates more compromised nodes. Our scheme also outperforms others in term of energy efficiency, especially for large sensor networks.
8948329
A strategic model for supply chain design with logical constraints: formulation and solution
This paper proposes a strategic production-distribution model for supply chain design with consideration of bills of materials (BOM). Logical constraints are used to represent BOM and the associated relationships among the main entities of a supply chain such as suppliers, producers, and distribution centers. We show how these relationships are formulated as logical constraints in a mixed integer programming (MIP) model, thus capturing the role of BOM in the selection of suppliers in the strategic design of a supply chain. A test problem is presented to illustrate the effectiveness of the formulation and solution strategy. The results and their managerial implications are discussed.