Is the cyclic prefix necessary?

We show that one can do away with the cyclic prefix (CP) for SC-FDE and OFDM at the cost of a moderate increase in the complexity of a DFT-based receiver. Such an approach effectively deals with the decrease in the number of channel uses due to the introduction of the CP. It is shown that the SINR for SC-FDE remains the same asymptotically with the proposed receiver without CP as that of the conventional receiver with CP. The results are shown for $N_t$ transmit antennas and $N_r$ receive antennas where $N_r \geq N_t$.Comment: 12 pages, 1 figure. Appeared in part in the Proceedings of International Symposium on Information Theory (ISIT), Seattle, WA, USA, July 200

On some special cases of the Entropy Photon-Number Inequality

We show that the Entropy Photon-Number Inequality (EPnI) holds where one of the input states is the vacuum state and for several candidates of the other input state that includes the cases when the state has the eigenvectors as the number states and either has only two non-zero eigenvalues or has arbitrary number of non-zero eigenvalues but is a high entropy state. We also discuss the conditions, which if satisfied, would lead to an extension of these results.Comment: 12 pages, no figure

Predicting and reducing warranty costs by considering customer expectation and product performance

This dissertation develops from quality loss function to warranty loss function in which customer expectation is also considered to be a variable. First, Taguchi\u27s quality loss function for the larger-the-better case, which is different from the smaller-the better and nominal-the-best cases, has been assimilated into the other two by introducing a term called the target-mean ratio. Further topics addressed include the implications of a finite target on the classification of LTB characteristics, a new concept of a Complementary Characteristic , operating window, complexity, and SN ratio based on complexity. A warranty is a buyer\u27s confidence owing to the seller\u27s assurance to the buyer that a product will perform as stated or implied. The quality loss function only accounts for immediate issues within manufacturing facilities, whereas the warranty cost occurs during customer use. Therefore, this dissertation develops a methodology that can predict warranty probability and warranty costs on the basis of customer expectation in addition to product performance for smaller-the-better, nominal-the-best, and larger-the-better cases. In robust engineering, the signal-to-noise ratio is used to improve the robustness of a system. Most products and processes have multiple quality characteristics or output responses. Therefore, this research has been conducted to propose a metric that can be used for multi-response experiments for minimizing quality loss and improving robustness at the same time. The methodology proposed incorporates all three types of characteristics smaller-the-better, nominal-the-best, and larger-the-better and is based on components of quality loss --Abstract, page iii

Ethnic differentials of the impact of Family Planning Program on contraceptive use in Nepal

There is wide variation of family planning services use among ethnic groups in Nepal. Despite three decades of implementation the need for family planning services is substantially unmet (25%), and there have been no systematic studies evaluating the impact of the family planning program. This study pooled data from nationally representative surveys conducted in 1996, 2001, and 2006. Multilevel logistic regression analysis of 23,381 married women of reproductive age nested within 764 clusters indicated that Muslims, Janjatis, and Dalits were significantly less likely to use contraceptives than Brahmins and Chhetries (OR=0.27, 0.88 and 0.82 respectively). The odds of using contraceptives by the Newar were higher than the odds for Brahmins and Chhetries, although it was not significant. Exposure of women to family planning messages through health facilities, family planning workers, radio, and television increased the odds of using modern contraceptives. However, the impact of family planning information on contraceptive use varied according to ethnicity. We also found that modern contraceptive use varied significantly across the clusters, and the cluster-level indicators, such as mean age at marriage, mean household asset score, percentage of women with secondary education, and percentage of women working away from home, were important in explaining this.ethnic differentials, family planning, family planning programs, Nepal