A Wannier-function-based ab initio Hartree-Fock study of polyethylene

In the present letter, we report the extension of our Wannier-function-based ab initio Hartree-Fock approach---meant originally for three-dimensional crystalline insulators---to deal with quasi-one-dimensional periodic systems such as polymers. The system studied is all-transoid polyethylene, and results on optimized lattice parameters, cohesive energy and the band structure utilizing 6-31G** basis sets are presented. Our results are also shown to be in excellent agreement with those obtained with traditional Bloch-orbital-based approaches.Comment: 15 Pages, RevTex, inludes four figures, Chem. Phys. Letts., in press (1998

Toward a Formalism for Conservative Claims about the Dependability of Software-Based Systems

In recent work, we have argued for a formal treatment of confidence about the claims made in dependability cases for software-based systems. The key idea underlying this work is "the inevitability of uncertainty": It is rarely possible to assert that a claim about safety or reliability is true with certainty. Much of this uncertainty is epistemic in nature, so it seems inevitable that expert judgment will continue to play an important role in dependability cases. Here, we consider a simple case where an expert makes a claim about the probability of failure on demand (pfd) of a subsystem of a wider system and is able to express his confidence about that claim probabilistically. An important, but difficult, problem then is how such subsystem (claim, confidence) pairs can be propagated through a dependability case for a wider system, of which the subsystems are components. An informal way forward is to justify, at high confidence, a strong claim, and then, conservatively, only claim something much weaker: "I'm 99 percent confident that the pfd is less than 10-5, so it's reasonable to be 100 percent confident that it is less than 10-3." These conservative pfds of subsystems can then be propagated simply through the dependability case of the wider system. In this paper, we provide formal support for such reasoning

How Referral Rewards Systems Shape What Tourists Share on Social Media

Sharing on social media not only relies on our intrinsic motivations but also can be induced by the extrinsic motivations such as referral rewards. Although our previous study demonstrated that incentivizing tourists to create postings could influence peer consumers’ behavioral intentions (i.e., purchase and word-of-mouth intentions) and social media engagement, we noticed that it was the content which was created under the incentive design drove all the impacts. Therefore, in this study, we extracted the content characteristics from the tourists’ postings we collected. Results indicated that the referral rewards systems (RRSs) we introduced could shape what tourists share, and the content characteristics such as positive emotional, utilitarian, high-level and low-level construal have different effects on peer consumers’ social media engagement and behavioral intentions. Our findings aid researchers and practitioners in understanding how to design successful RRSs and how to create viral content on social media

MOTIVATION AND RECRUITMENT OF PUBLIC SERVANTS - THE ETHOS OR THE MANAGERIAL MODEL?

The need to continue the reduction of the state bureaucracy and the orientation towards the managerial models from the private sector, the usage of financial incentive systems, generally in the form of merit base promotion and financial rewards, have introduced in the public system the incentives of the market, aiming to lead towards the efficiency and the effectiveness of the private organizations. Those practices considered that the labor force in the public and private systems is substantially the same, avoiding the essential differences between the public and private employees. The public servant does not answer only to financial incentives; a variety of nonfinancial motives affect the behavior: trust, sense of duty, altruism or community reputation. Public managers need to carefully balance the incidence and consistency of financial motivation in time with the impact on the organizational performance as well to avoid treating the public organization as a private company because such a measure does not identify the specific motives of public service and the way a bureaucracy works.Motivation, recruitment, employees, public administration, private companies

Receiver Architectures for MIMO-OFDM Based on a Combined VMP-SP Algorithm

Iterative information processing, either based on heuristics or analytical frameworks, has been shown to be a very powerful tool for the design of efficient, yet feasible, wireless receiver architectures. Within this context, algorithms performing message-passing on a probabilistic graph, such as the sum-product (SP) and variational message passing (VMP) algorithms, have become increasingly popular. In this contribution, we apply a combined VMP-SP message-passing technique to the design of receivers for MIMO-ODFM systems. The message-passing equations of the combined scheme can be obtained from the equations of the stationary points of a constrained region-based free energy approximation. When applied to a MIMO-OFDM probabilistic model, we obtain a generic receiver architecture performing iterative channel weight and noise precision estimation, equalization and data decoding. We show that this generic scheme can be particularized to a variety of different receiver structures, ranging from high-performance iterative structures to low complexity receivers. This allows for a flexible design of the signal processing specially tailored for the requirements of each specific application. The numerical assessment of our solutions, based on Monte Carlo simulations, corroborates the high performance of the proposed algorithms and their superiority to heuristic approaches

Implications for academic libraries

This paper may present a more restricted view of the academic library interface with collective bargaining than might have been anticipated, primarily for three reasons. First, I am more familiar with the Canadian academic library situation than with the American, although I have studied the pattern which appears to be emerging in American libraries. In addition, I am convinced that if academic library administrators had realized at any point within the past ten years that library management is a unique and demanding scientific discipline and had borrowed some of the techniques and methodologies being practiced in the business community, they could have been in a position of bargaining from strength rather than from weakness. Finally, I am firmly committed to the belief that academic librarians should achieve their status and any ensuing rights and privileges through their own merit, and not by accepting a system designed for another profession with similar, but not identical, objectives and requirements.published or submitted for publicatio