Sequence Design via Semidefinite Programming Relaxation and Randomized Projection

Wideband is a booming technology in the field of wireless communications. The receivers in wideband communication systems are expected to cover a very wide spectrum and adaptively extract the parts of interest. The literature has focused on mixing the input spectrum to baseband using a pseudorandom sequence modulation and recovering the received signals from linearly independent measurements by parallel branches to mitigate the pressures from required extreme high sampling frequency. However, a pseudorandom sequence provides no rejection for the strong interferers received together with weak signals from distant sources. The interferers cause significant distortion due to the nonlinearity of the subsequent amplifier and mask the weak signals. In this dissertation, we optimize the modulation sequences with a specific spectrum shape to mitigate interferers while preserving messages; the sequences have binary entries to simplify hardware implementation. Though the resulting sequence design problems are NP-hard, we solve them approximately by semidefinite relaxation and randomized projection. First, we formulate the design algorithm for a single spectrally shaped binary sequence base on a randomized convex optimization method. We analyze the performance of the algorithm in obtaining binary sequences and show its advantages compared with method available in the literature. And, we show a comparison between the proposed sequence design method with the exhaustive approaches when feasible. Additionally, we propose several custom sequence scoring functions that allow for an improved selection of binary sequences for message preservation and interference rejection. Second, we propose an algorithm to design a multi-branch set of binary sequences one by one by introducing the constrains on the orthogonality between pairs of sequences. Numerical results show the proposed algorithm obtains sequences with a small search size compared with the exhaustive search. Finally, we extend the randomized method to multi-branch sequence design. In order to avoid the unstable performance and high complexity of designing multi-branch sequence iteratively, the whole branch sequences will be obtained directly via matrix randomized projection from the relaxed problems

Brand Recognition, Interdepartmental Conflict, and Performance: An Investigation of Porter's Differentiated Competitive Strategy Implementation in a Large Chinese Automobile Company

Due to the unique market context and consumer differences, Porter’s generic competitive strategy has often failed in China. This study examined the impacts of managerial factors on performance by using the company brand as an indicator of performance; furthermore, we discuss the management issues of Chang’an when adopting a differentiated competitive strategy. This research used a quantitative method to form a consumer cognition map and compared product brands with competitors. It also investigated the managerial factors of the case company that affected the implementation of a differentiated competitive strategy. Interviews of the managers from the case company were also conducted to provide an in-depth understanding of management issues. The results show that the case company, Chang’an, as a large state-owned automobile manufacturer, failed to generate satisfactory outcomes by implementing a differentiation strategy. The reasons for the unfavorable enterprise performance include unclear departmental role positioning, a lack of communication mechanisms, and missing evaluation mechanisms. This research offers an in-depth investigation of the application of Porter’s differentiated competitive strategy in a Chinese state-owned company (there has been little academic attention on this). Since many state-owned companies use similar management structures, the results of this research can help managers find management problems and fix them

Nucleon Form Factors in a Light-Cone Quark Model with Two-Photon Exchange

We estimate the two-photon exchange corrections to both proton and neutron electromagnetic physical observables in a relativistic light cone quark model. At a fixed momentum transfer the corrections are found to be small in magnitudes, but with a strong angular dependence. Our results are comparable to those from simple hadronic model in a moderate momentum transfer region.Comment: 10 pages, 5 figure

Prevalence and Factors Associated with Leishmania infantum Infection of Dogs from an Urban Area of Brazil as Identified by Molecular Methods

Visceral leishmaniasis (VL) is a disease caused by the parasite Leishmania infantum, and dogs are the most important domestic reservoirs of the agent. During recent decades, VL has expanded to large Brazilian urban centers. In the present work, we have demonstrated by using molecular techniques that the rate of canine infection as detected by serology has been considerably underestimated. Two groups of seronegative dogs (infected and non-infected according to molecular methods) were further evaluated from data obtained through interviews with owners of the animals. The factors associated with Leishmania infection in dogs were a family income of less than two minimum salaries, the knowledge of the owner regarding the vector, the dog spending most of its time in the backyard and the dog never having had a previous serological examination. Awareness regarding the factors associated with canine infection will improve health services and the understanding of the disease's expansion in urban areas

Relatório de estágio em farmácia comunitária

Relatório de estágio realizado no âmbito do Mestrado Integrado em Ciências Farmacêuticas, apresentado à Faculdade de Farmácia da Universidade de Coimbr

Compressive Parameter Estimation with Emd

In recent years, sparsity and compressive sensing have attracted significant attention in parameter estimation tasks, including frequency estimation, delay estimation, and localization. Parametric dictionaries collect signals for a sampling of the parameter space and can yield sparse representations for the signals of interest when the sampling is sufficiently dense. While this dense sampling can lead to high coherence in the dictionary, it is possible to leverage structured sparsity models to prevent highly coherent dictionary elements from appearing simultaneously in a signal representation, alleviating these coherence issues. However, the resulting approaches depend heavily on a careful setting of the maximum allowable coherence; furthermore, their guarantees apply to the coefficient vector recovery and do not translate in general to the parameter estimation task. We propose a new algorithm based on optimal sparse approximation measured by earth mover\u27s distance (EMD). Theoretically, we show that EMD provides a better metric for the performance of parametric dictionary-based parameter estimation and $K$-median clustering algorithms has the potential to solve the EMD-optimal sparse approximation problems. Simulations show that the resulting compressive parameter estimation algorithm is better at addressing the coherence issuers without a careful setting of additional parameters

高中學生次級文化及其在我國教育上的意義

[[abstract]]本研究的目的在於：一、分析高中學生次級文化的形成原因及其在教育上的意 義。二、探討改變學生次級文化的因素。三、瞭解我國高中學生次級文化的特徵。 四、提出建議，以供改進高中教育的參考。 研究方法係採理論分析及調查的方法，先澄清次級文化的性質，確定問題的範 圍，就理論的觀點分析學生次級文化形成的原因，學生同儕團體的教育功能，學生 次級文化的理論及其在教育上的意義。繼則設計問卷，調查我國高中學生次級文化 的特徵：及改變此特徵的影響因素，將前者的理論基礎應用在實際的調查發現，予 以討論而提出結論與建議。