Convolutional compressed sensing using deterministic sequences

This is the author's accepted manuscript (with working title "Semi-universal convolutional compressed sensing using (nearly) perfect sequences"). The final published article is available from the link below. Copyright @ 2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.In this paper, a new class of orthogonal circulant matrices built from deterministic sequences is proposed for convolution-based compressed sensing (CS). In contrast to random convolution, the coefficients of the underlying filter are given by the discrete Fourier transform of a deterministic sequence with good autocorrelation. Both uniform recovery and non-uniform recovery of sparse signals are investigated, based on the coherence parameter of the proposed sensing matrices. Many examples of the sequences are investigated, particularly the Frank-Zadoff-Chu (FZC) sequence, the m-sequence and the Golay sequence. A salient feature of the proposed sensing matrices is that they can not only handle sparse signals in the time domain, but also those in the frequency and/or or discrete-cosine transform (DCT) domain

Dual-lattice ordering and partial lattice reduction for SIC-based MIMO detection

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2009 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.In this paper, we propose low-complexity lattice detection algorithms for successive interference cancelation (SIC) in multi-input multi-output (MIMO) communications. First, we present a dual-lattice view of the vertical Bell Labs Layered Space-Time (V-BLAST) detection. We show that V-BLAST ordering is equivalent to applying sorted QR decomposition to the dual basis, or equivalently, applying sorted Cholesky decomposition to the associated Gram matrix. This new view results in lower detection complexity and allows simultaneous ordering and detection. Second, we propose a partial reduction algorithm that only performs lattice reduction for the last several, weak substreams, whose implementation is also facilitated by the dual-lattice view. By tuning the block size of the partial reduction (hence the complexity), it can achieve a variable diversity order, hence offering a graceful tradeoff between performance and complexity for SIC-based MIMO detection. Numerical results are presented to compare the computational costs and to verify the achieved diversity order

The Welfare Effects of Monopoly Innovation

In this paper we study the welfare effect of a monopoly innovation. Unlike many partial equilibrium models carried out in previous studies, general equilibrium models are constructed and analyzed in greater details. We discover that, technical innovation carried out by a monopolist could significantly increase the social welfare. We conclude that, in general, the criticism against monopoly innovation based on its increased dead weight loss is less accurate as previously postulated by many studies.

The Profiles of Software Pirates among Tertiary Institutions in Singapore

The study seeks to examine the perception of software piracy as well as to discover its underlying factors among Singapore’s three university communities. Some five hundred responses were gathered from students and staff. By means of cluster analysis and factor analysis, the results identify three clusters of pirate profiles as influenced by factors such as attitudes towards software publishers, general acceptance, convenience, and ethics. The decision tree method links each pirate profile to demographic and computer-related variables. It shows that while age is negatively related to software piracy, computer experience and computer usage demonstrates an ambiguous relationship to software piracy respectively. Further, the undergraduate students tend to be pirates more often than university employees, and the Malays tend to be less frequent pirates as compared to other races. It is hoped that the study will help the relevant policy makers to develop better strategies to protect and to enforce the intellectual property rights among the universities as well as in an increasingly knowledge-based economy such as Singapore.Software Piracy; Software Policy; Protection and Enforcement of Intellectual Property Rights; Cluster Analysis; Factor Analysis.

Stein factors for negative binomial approximation in Wasserstein distance

The paper gives the bounds on the solutions to a Stein equation for the negative binomial distribution that are needed for approximation in terms of the Wasserstein metric. The proofs are probabilistic, and follow the approach introduced in Barbour and Xia (Bernoulli 12 (2006) 943-954). The bounds are used to quantify the accuracy of negative binomial approximation to parasite counts in hosts. Since the infectivity of a population can be expected to be proportional to its total parasite burden, the Wasserstein metric is the appropriate choice.Comment: Published at http://dx.doi.org/10.3150/14-BEJ595 in the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

Credit Card Selection Criteria: Singapore Perspective

This study used factor analysis to examine credit card selection criteria among Singaporeans. The results showed that convenience of use and protection, economics, and flexibility were the main drivers, while the reputation of card was the least important in determining credit card selection in Singapore. Demographic results showed that high-income earners, the better educated, the elderly, married and the professional preferred the convenience-protection factor to the economic-promotional factor. Females were shown to value the promotional factor more, while males preferred the economic factor. The ethnic Malays placed a greater emphasis on the economic factor than did the ethnic Chinese. The results also showed that the number of credit card owned in Singapore is positively related to education, income, age group, and marital status. Those holding a single credit card stressed the economic factor more than those holding many cards. In Singapore, the higher income earners, the better educated, older adults, females, married, and both Chinese and Indians are more receptive to paying their monthly credit card balances in full. The results demonstrated that Singaporeans do not view the credit card selection criteria much differently from respondents from other developing and advanced nations.credit card selection, credit card usage, banking regulation, factor analysis