8 research outputs found
Clock skew invariant beamforming: for a wireless acoustic sensor network
This thesis is focused on Wireless Acoustic Sensor Networks (WASNs) used for beamforming in a speech enhancement task. Since each node in a WASN has its own clock, clock offsets and clock skews between the nodes are inevitable. Clock offsets and clock skew can be detrimental to the beamformer performance. In this thesis we focus on the effect of clock skew on the beamformer performance. Existing methods for clock skew compensation for the speech enhancement application do this explicitly. In this thesis we investigate the possibility to formulate the beamformer such that explicit clock skew compensation is not necessary. Instead, we propose an algorithm for implicit clock skew compensation, which takes advantage of the Generalized Eigenvalue Decomposition (GEVD) to construct beamformers (e.g. Minimum Variance Distortionless Response (MVDR)), recently proposed in the literature. Using the GEVD, no explicit compensation has to be applied to the received data. Compared to the state-of-the-art, where clock skew estimation/compensation algorithms are used, this reduces the computational complexity for beamformer processing. The algorithm depends on exact knowledge of the noisy correlation matrix across the microphones. In practice, this matrix is unknown and estimation will reduce the performance of the proposed algorithm. We therefore quantify the error made in the estimation of the correlation matrix using the standard Welch method and also look at a recursive smoothing based method for correlation matrix estimation. Compared to a selected state-of-the-art algorithm, the proposed algorithm shows similar or better performance using this recursive smoothing method. For future work on this subject, more study can be done on correlation matrix estimation methods, as these play a key role in clock skew invariant beamforming.Electrical Engineering | Circuits and System
Een interview met Latour: modes of existence, diplomatie, en de sociologie
status: publishe
‘As long as they keep away from me’: The paradox of antigay violence in a gay-friendly country
Considering the tolerant and gay-friendly image of the Netherlands, antigay violence is a remarkably grave problem. By combining a broad survey of Amsterdam youth with in-depth interviews with smaller groups and individual attackers and reviewing recent cases, we conclude that traditional norms of gender and sexuality present in broader society form the breeding ground of the violence. The gay-friendly narrative that dominates discussions on citizenship in the Netherlands - opposing the liberal ‘Dutch’ to the Muslim ‘Other’ - coexists next to traditional norms of gender and sexuality, thereby not challenging the roots of homonegativity. Even perpetrators duplicate the prevailing gaytolerant rhetoric of Dutch society, but do not refrain from all sorts of violence as soon as they are confronted with aspects of it that collide with traditional norms of gender and sexuality. Peer pressure and the fear of seduction often function as triggers of the violence. However, these situational factors can only be understood in a larger macrosociological framework, showing the necessity of a multilevel approach in coming towards a comprehensive understanding of antigay violence
Outcome of allogeneic transplantation in newly diagnosed and relapsed/refractory multiple myeloma: long-term follow-up in a single institution
Allogeneic stem cell transplantation (allo-SCT) has the potential to induce long-term remission in multiple myeloma (MM), but the role of allo-SCT in MM is controversial due to the high rate of treatment-related mortality (TRM). However, although proteasome inhibitors and immunomodulatory drugs have improved the outcome of MM patients, high-risk patients still have a very poor prognosis. This indicates the need for new treatment strategies and identification of patients who might benefit from allo-SCT. We therefore analyzed the outcome of one hundred and forty-seven MM patients who received an allo-SCT at our institution (58 in first line, 89 in relapsed/refractory setting) after a median follow up of 88.8 months. For the first line setting, median PFS and OS were remarkably good, with a CR rate of 48.3%, median PFS of 30.2 months and 10-year OS of 51%. We found no difference in outcome for patients with high-risk metaphase cytogenetics or FISH del(13q14), but efficacy in current standard high-risk patients could not be determined. The outcome in the relapsed/refractory setting was poor, especially in the subgroup of patients relapsing within 18 months after auto-SCT. Therefore, if applied at all in these patients, improvement of allo-SCT is needed, focusing on reduction of TRM and more effective immunotherapy
Outcome of allogeneic transplantation in newly diagnosed and relapsed/refractory multiple myeloma : long-term follow-up in a single institution
Allogeneic stem cell transplantation (allo-SCT) has the potential to induce long-term remission in multiple myeloma (MM), but the role of allo-SCT in MM is controversial due to the high rate of treatment-related mortality (TRM). However, although proteasome inhibitors and immunomodulatory drugs have improved the outcome of MM patients, high-risk patients still have a very poor prognosis. This indicates the need for new treatment strategies and identification of patients who might benefit from allo-SCT. We therefore analyzed the outcome of one hundred and forty-seven MM patients who received an allo-SCT at our institution (58 in first line, 89 in relapsed/refractory setting) after a median follow up of 88.8 months. For the first line setting, median PFS and OS were remarkably good, with a CR rate of 48.3%, median PFS of 30.2 months and 10-year OS of 51%. We found no difference in outcome for patients with high-risk metaphase cytogenetics or FISH del(13q14), but efficacy in current standard high-risk patients could not be determined. The outcome in the relapsed/refractory setting was poor, especially in the subgroup of patients relapsing within 18 months after auto-SCT. Therefore, if applied at all in these patients, improvement of allo-SCT is needed, focusing on reduction of TRM and more effective immunotherapy.