Bayesian Speaker Adaptation Based on a New Hierarchical Probabilistic Model

In this paper, a new hierarchical Bayesian speaker adaptation method called HMAP is proposed that combines the advantages of three conventional algorithms, maximum a posteriori (MAP), maximum-likelihood linear regression (MLLR), and eigenvoice, resulting in excellent performance across a wide range of adaptation conditions. The new method efficiently utilizes intra-speaker and inter-speaker correlation information through modeling phone and speaker subspaces in a consistent hierarchical Bayesian way. The phone variations for a specific speaker are assumed to be located in a low-dimensional subspace. The phone coordinate, which is shared among different speakers, implicitly contains the intra-speaker correlation information. For a specific speaker, the phone variation, represented by speaker-dependent eigenphones, are concatenated into a supervector. The eigenphone supervector space is also a low dimensional speaker subspace, which contains inter-speaker correlation information. Using principal component analysis (PCA), a new hierarchical probabilistic model for the generation of the speech observations is obtained. Speaker adaptation based on the new hierarchical model is derived using the maximum a posteriori criterion in a top-down manner. Both batch adaptation and online adaptation schemes are proposed. With tuned parameters, the new method can handle varying amounts of adaptation data automatically and efficiently. Experimental results on a Mandarin Chinese continuous speech recognition task show good performance under all testing conditions

Study on Forging Ahead Strategy of Developing Country from the Perspective of Comparative Advantage

New trade theory, which is the representative of the contemporary comparative advantage theory, has become the mainstream trade theory, but the theory is developed in the country whose market economy is relative developed, and therefore it has not analyzed problems from the perspective of developing countries. New trade theory reveals the positive role that technology plays in trade, but it does not discuss how the developing country should do to realize catching up and surpassing by using technology and it does not give the instruction on how the developing countries can skip comparative benefit trap. From the perspective of comparative advantage, this paper establishes the game models between developed countries and between developed and developing countries, and points out that the developing countries can’t narrow the gap with the developed countries and achieve national economy takeoff until they implement the Forging Ahead Strategy. Key words: comparative advantage, forging ahead strategy, Game Résumé: La nouvelle théorie du commerce, qui est représentative de la théorie de l’avantage comparatif contemporaine, est devenue la tendance générale de la théorie commerciale. Mais cette théorie est développée dans des pays dont l’économie de marché est relativement développée, et ainsi elle n’a pas analysé les problèmes sous l’angle des pays en développement. La nouvelle théorie du commerce révèle le rôle positif de la technologie dans le commerce, mais elle ne discute pas comment les pays en développement doivent faire pour rattraper et surpasser avec l’aide de la technologie, et elle ne donne pas non plus l’instruction sur comment les pays en développement peuvent éviter le piège de bénéfice comparatif. Dans la perspective de l’avantage comparatif, le présent article établit des modèles de jeu entre les pays développés et les pays en développement, et indique que les pays en développement ne peuvent raccourcir l’écart avec les pays développés et accomplir l’essor de l’économie nationale que s’ils mettent en oeuvre la Stratégie d’aller de l’avant. Mots-Clés: avantage comparatif, stratégie d’aller de l’avant, je

Joint Secure Communication and Radar Beamforming: A Secrecy-Estimation Rate-Based Design

This paper considers transmit beamforming in dual-function radar-communication (DFRC) system, where a DFRC transmitter simultaneously communicates with a communication user and detects a malicious target with the same waveform. Since the waveform is embedded with information, the information is risked to be intercepted by the target. To address this problem, physical-layer security technique is exploited. By using secrecy rate and estimation rate as performance measure for communication and radar, respectively, three secrecy rate maximization (SRM) problems are formulated, including the SRM with and without artificial noise (AN), and robust SRM. For the SRM beamforming, we prove that the optimal beamformer can be computed in closed form. For the AN-aided SRM, by leveraging alternating optimization similar closed-form solution is obtained for the beamformer and the AN covariance matrix. Finally, the imperfect CSI of the target is also considered under the premise of a moment-based random phase-error model on the direction of arrival at the target. Simulation results demonstrate the efficacy and robustness of the proposed designs.Comment: 14 page