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Limits in FIR Subband Beamforming for Spatially Spread Nearfield Sources

This paper analyses optimal subband beamforming performance mainly aimed at speech enhancement and acoustic echo suppression for personal communication devices, personal computers and wireless cellular telephones. The focus is on theoretical limits of finite impulse response (FIR) beamformers for spatially spread sources in the array near-field. Performance of the Wiener solution is compared to th

Prosumers in district heating networks - A Swedish case study

A prosumer is a customer that both uses and supplies energy, such as electricity or district heat. These are already a part of the electricity system. Lately, prosumers have also been discussed as a part of the district heating systems. This calls for more knowledge in this area. The present study seeks to evaluate the potential for district heating contribution from small scale prosumers, based o

Metabolic and behavioral effects of mutant huntingtin deletion in Sim1 neurons in the BACHD mouse model of Huntington's disease

Hypothalamic pathology, metabolic dysfunction and psychiatric symptoms are part of Huntington disease (HD), which is caused by an expanded CAG repeat in the huntingtin (HTT) gene. Inactivation of mutant HTT selectively in the hypothalamus prevents the development of metabolic dysfunction and depressive-like behavior in the BACHD mouse model. The hypothalamic paraventricular nucleus (PVN) is implic

Neural Network Based Adaptive Microphone Array System for Speech Enhancement

Presents a microphone array system for use in handsfree mobile telephone equipment. The array is based on a fast and efficient “on-site” and “self-calibration” scheme. The performance in suppressing the interior car cabin noise and the far-end speech is approximately 17 dB, respectively, while maintaining the near-end speaker level. The near-end signal is almost undistorted. The performance of two

A New Pilot-Signal based Space-Time Adaptive Algorithm

In the application of adaptive antenna arrays to wireless communications, a known pilot signal sequence may be used for estimating the array response at the beginning of each data frame. This pilot sequence is usually very short and conventional training methods which estimate the array response, based solely on this training sequence, may incur large estimation errors. In this paper, we propose a

Adaptive beamformer with recursively updated quadratic constraints

A novel adaptive beamformer employing recursively updated soft constraints for acoustic speech enhancement is proposed. The beamformer operates in a subband structure to allow time-frequency operation for each channel. As such, the processing can be viewed as a combination of weighted spatial and temporal filters. The major benefit of this recursive soft constrained beamformer is that it allows th

A Subband Space Constrained Beamformer incorporating Voice Activity Detection

This paper introduces a new subband adaptive space constrained beamforming structure for use in hands-free speech enhancement applications. The scheme incorporates a space constrained source model and voice activity information through the integration of a voice activity detector (VAD). The VAD information is used to estimate noise covariance information during non-speech periods and to optimally

Beamforming for moving source speech enhancement

This paper presents a new constrained subband beamforming algorithm to enhance speech signals generated by a moving source in a noisy environment. The beamformer is based on the principle of a soft constraint defined for a specified region corresponding to a known source location. The soft constraint secures the spatial-temporal passage of the desired source signal in the adaptive update of the be

Land access constraints for communities affected by large-scale land acquisition in Southern Sierra Leone

While national figures of land availability are used to justify accepting large-scale land investors, not very much is known about the local level realities of land availability. By combining remotely sensed data with fieldwork, system dynamics modelling and qualitative research methods, we examine local level realities of land use and availability in the Malen Chiefdom of Southern Sierra Leone. H

On optimal low-rank approximation of non-negative matrices

For low-rank Frobenius-norm approximations of matrices with non-negative entries, it is shown that the Lagrange dual is computable by semi-definite programming. Under certain assumptions the duality gap is zero. Even when the duality gap is non-zero, several new insights are provided.

Leadership as Social Integrative Action. A Study of a Computer Consultancy CompanyLeadership as social integrative action

In this paper it is suggested that leadership, at least in some types of organiza tions, can be conceptualized as social integrative action. Such action is seen as a synthesis of institutional and human relations-oriented leadership. A case study of a computer consultancy company, a professional service adhocracy, supports this argument. This paper also argues for viewing leadership as an expressi

Development of a Scheimpflug Lidar System for Atmospheric Aerosol Monitoring

This work presents a Scheimpflug lidar system which was employed for atmospheric aerosol monitoring in southern Sweden. Atmospheric aerosol fluctuation was observed around rush-hour. The extinction coefficient over 6 km was retrieved, i.e., 0.15 km-1, by employing the slop-method during the time when the atmosphere was relatively homogenous. The measurements successfully demonstrate the potential

Beyond the Creative Commons Framework of Production and Dissemination of Knowledge

The thesis discusses the licensing system of the Creative Commons from the perspective of the theory of the commons mostly as formulated by Elinor Ostrom. The work starts by describing the concepts and theory of common pool resources and regime of the commons for production and distribution of these resources. The main characteristics for successful traditional commons – efficiency, equity and sus