32208283
A Bidirectional Adaptive Sequential Gaussian Approximation for MIMO Systems
A bidirectional adaptive detection method was proposed to prevent error propagation based on sequential Gaussian approximation algorithm for MIMO systems. Conventional sequential Gaussian approximation detection executes a tree search at the receiver, when the number of searching paths is large, error propagation is well prevented at the cost of high complexity, when few paths are searched, serious error propagation may occur. In the new method, transmitted symbols were estimated parallel both in sequential order and inverse order, and the number of searching paths was determined by comparing the results of bidirectional detection, which can effectively prevent error propagation at reduced complexity. The novel algorithm can be executed at low delay because of parallel computing, and shows good performance at low complexity.
44633498
Simulation of the defect removal process with queuing theory
16656616
A smoothed dynamic tabu search embedded GRASP for m-VRPTW
Vehicle routing problem with both time window and limited number of vehicles (m-VRPTW) is an useful extension of VRPTW problem in real applications. We propose an improved greedy randomized adaptive search procedure (GRASP) framework by techniques including multiple initialization and solution reuse. Furthermore, a new technique of smoothed dynamic tabu search is embedded into the GRASP to improve the performance. The experimental results for benchmark data show that the new algorithm can solve the m-VRPTW problem better than the published algorithm in accuracy.
15143128
Multi-channel spectrum-agile MAC protocol with adaptive load control
Spectrum-agile radios, also known as cognitive radios, have a great potential to improve spectrum utilization by enabling dynamic access to the spectrum. A key challenge in operating these radios is how to implement an efficient medium access control (MAC) mechanism that adaptively and efficiently allocates transmission powers and spectrum according to the surrounding environment. In this work, we propose a distributed MAC protocol for operating spectrum-agile radios in a multihop ad hoc network. Our protocol differs from previous designs in that it exploits the “dual-receive” capability of radios, thus overcoming various channel access problems that are common to multi-channel designs. We conduct theoretical analysis of the protocol, and study its performance via simulations. We show significant improvement in the system throughput under the proposed MAC design. To maximize this throughput, we propose a cross-layer framework for joint adaptive load and medium access controls. In this framework, the loads of individual nodes are adapted based on the values of local MAC parameters. Simulation results show that the proposed scheme achieves more than 90% of the maximum (global) system throughput that is achieved at saturation, while guaranteeing low collision rates.
121559751
Ab initio ro-vibrational structure of the C 2n isotopes of H 2 O +
The ro-vibrational structures of the C2" isotopes ofH20+ have been calculated from variational solution of the normal coordinate Eckart-Watson Hamiltonian. The calculations use the discrete ab initio potential energy surface of Weis et al. (1989). Where comparisons can be made, the assignment of the vibrational states is in excellent agreement with experiment and with the ab initio variational calculation of Weis et al., who utilised a different force field and an internal coordinate nuclear Hamiltonian (instead of the Eckart-Watson amiltonian). Furthermore, the calculated rotational levels of the ground and the first excited vibrational states of H20+ and D20+ are in excellent agreement with experiment.
15473023
Query Planning for Searching Inter-dependent Deep-Web Databases
Increasingly, many data sources appear as online databases, hidden behind query forms, thus forming what is referred to as the deep web. It is desirable to have systems that can provide a high-level and simple interface for users to query such data sources, and can automate data retrieval from the deep web. However, such systems need to address the following challenges. First, in most cases, no single database can provide all desired data, and therefore, multiple different databases need to be queried for a given user query. Second, due to the dependencies present between the deep-web databases, certain databases must be queried before others. Third, some database may not be available at certain times because of network or hardware problems, and therefore, the query planning should be capable of dealing with unavailable databases and generating alternative plans when the optimal one is not feasible. 
 
This paper considers query planning in the context of a deep-web integration system. We have developed a dynamic query planner to generate an efficient query order based on the database dependencies. Our query planner is able to select the topKquery plans. We also develop cost models suitable for query planning for deep web mining. Our implementation and evaluation has been made in the context of a bioinformatics system, SNPMiner. We have compared our algorithm with a naive algorithm and the optimal algorithm. We show that for the 30 queries we used, our algorithm outperformed the naive algorithm and obtained very similar results as the optimal algorithm. Our experiments also show the scalability of our system with respect to the number of data sources involved and the number of query terms.
42343733
On the Selection and Assignment with Minimum Quantity Commitments
Traditional selection and assignment problems analyze how to select and assign the suppliers to meet demands within minimum total costs. The maximum capacity and the fixed selection costs are two major restrictions imposed on suppliers, and extensively studied in literature.