Ab initio study of shock compressed oxygen

Quantum molecular dynamic simulations are introduced to study the shock compressed oxygen. The principal Hugoniot points derived from the equation of state agree well with the available experimental data. With the increase of pressure, molecular dissociation is observed. Electron spin polarization determines the electronic structure of the system under low pressure, while it is suppressed around 30 $\sim$ 50 GPa. Particularly, nonmetal-metal transition is taken into account, which also occurs at about 30 $\sim$ 50 GPa. In addition, the optical properties of shock compressed oxygen are also discussed.Comment: 5 pages, 5 figure

Diagonally Implicit Symplectic Runge-Kutta Methods with High Algebraic and Dispersion Order

The numerical integration of Hamiltonian systems with oscillating solutions is considered in this paper. A diagonally implicit symplectic nine-stages Runge-Kutta method with algebraic order 6 and dispersion order 8 is presented. Numerical experiments with some Hamiltonian oscillatory problems are presented to show the proposed method is as competitive as the existing same type Runge-Kutta methods

Relationship and Contract Issues of IT Outsourcing – Descriptive Case Studies in China Regions

In spite of the continuous increase in IT outsourcing activities globally, a major percentage of outsourcing deals failed or suffered from serious problems. In China regions where IT outsourcing practice is still at its initial stage, the situation is even serious: there lacks systematic guidance in terms of how to negotiate decent contracts and how to develop sound relationships. In view of this, the current research develops a research framework based on the theories in Economics, Management and Marketing fields, and investigates the effects of both relationship and contract on IT outsourcing success. To support the research framework, evidence was collected from two descriptive case studies conducted in Hong Kong and Mainland China. The case analysis implies the dimensionalities of relationship and contract. What is more, IT outsourcing success is mainly evaluated from the technological benefits client company could gain. A significant contribution of this study to theory is to look into IT outsourcing phenomenon with a balanced view and through an integrated theoretical lens. For practitioners, this research removes executives’ doubts about simultaneously employing both relationship (soft side) and contract (hard side) as governance mechanisms in managing IT outsourcing deals

State Transfer of Two-level Quantum System Feedback Control Based on Online State Estimation

A quantum state feedback control method is proposed in this paper. The state of a two-level open quantum system is estimated online based on the continuous weak measurement and the compressed sensing theory. Based on the state estimated online and the Lyapunov stability theorem, the state feedback control law used to transfer the quantum state is designed. Moreover, three numerical simulation experiments are implemented in the MATLAB environment: the state transfer from eigenstates to eigenstates, superposition states to superposition states, and superposition states to mixed states. The experimental results verify high performance of the proposed feedback control based on the state estimated online

Placement-Driven Technology Mapping for LUT-Based FPGAs

In this paper, we study the problem of placement-driven technology mapping for table-lookup based FPGA architectures to optimize circuit performance. Early work on technology mapping for FPGAs such as Chortle-d[14] and Flowmap[3] aim to optimize the depth of the mapped solution without consideration of interconnect delay. Later works such as Flowmap-d[7], Bias-Clus[4] and EdgeMap consider interconnect delays during mapping, but do not take into consideration the effects of their mapping solution on the final placement. Our work focuses on the interaction between the mapping and placement stages. First, the interconnect delay information is estimated from the placement, and used during the labeling process. A placement-based mapping solution which considers both global cell congestion and local cell congestion is then developed. Finally, a legalization step and detailed placement is performed to realize the design. We have implemented our algorithm in a LUT based FPGA technology mapping package named PDM (Placement-Driven Mapping) and tested the implementation on a set of MCNC benchmarks. We use the tool VPR[1][2] for placement and routing of the mapped netlist. Experimental results show the longest path delay on a set of large MCNC benchmarks decreased by 12.3 % on the average

A fast algorithm for the spread of HIV in a system of prisons

In this paper, we propose a continuous time model for modelling the spread of HIV in a network of prisons. We give some sufficient conditions for the equilibrium points of the system to be stable. We also develop an efficient algorithm based on Newton's method and the Sherman-Morrison-Woodbury formula for computing the equilibrium values of the infectives in each prison. © 2007 Elsevier Ltd. All rights reserved.preprin

An efficient method of computing impact degrees for multiple reactions in metabolic networks with cycles

The impact degree is a measure of the robustness of a metabolic network against deletion of single or multiple reaction(s). Although such a measure is useful for mining important enzymes/genes, it was defined only for networks without cycles. In this paper, we extend the impact degree for metabolic networks containing cycles and develop a simple algorithm to calculate the impact degree. Furthermore we improve this algorithm to reduce computation time for the impact degree by deletions of multiple reactions. We applied our method to the metabolic network of E. coli, that includes reference pathways, consisting of 3281 reaction nodes and 2444 compound nodes, downloaded from KEGG database, and calculate the distribution of the impact degree. The results of our computational experiments show that the improved algorithm is 18.4 times faster than the simple algorithm for deletion of reaction-pairs and 11.4 times faster for deletion of reaction-triplets. We also enumerate genes with high impact degrees for single and multiple reaction deletions. © 2011 The Institute of Electronics, Information and Communication Engineers.published_or_final_versio