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In multi-sensor data fusion target tracking system, using information filtering can implement distributed location with uncorrelated measurement noises, but the measurement noises of different sensors are often correlated. If measurement noises are correlated, the covariance matrix of measurement noises is not a diagonal matrix. We can not use information filtering to implement distributed location with correlated measurement noises. By using the matrix theory, the covariance matrix of measurement noises can be transformed to a diagonal matrix. The observation models are transformed to new observation models, and the multi-sensor measurements with correlated measurement noises are transformed to equivalent pseudo ones with uncorrelated measurement noises. There are many methods in the matrix theory, we use Cholesky fatorization in this thesis. Cholesky fatorization is from Gaussian elimination, and there are many advantages in the computation process.However, the observation models need to be transformed to new observation models, and the measurement datas for the approach need to be separated and recombined. For measurement datas being separated and recombined, every sensor must communicate with each other. In practice, one sensor does not directly communicate with other sensors except its direct neighbors. By formulating the Cholesky factorization process, we present architectures which are applied in wireless distributed location. Distributed architectures with clustered nodes are proposed to achieve measurement exchange and information sharing for wireless location and target tracking. With limited times of data exchanges between clustered nodes, the correlated noise components in the measurements are transformed into uncorrelated ones through the Cholesky process, and the resultant information can be directly shared and processed by the derived extended information filters at the nodes in the distributed system. Hybrid TDOA/AOA wireless location systems with the NLOS error effects are used as examples in investigating the distributed information architecture. Simulation results show that the proposed distributed information processing and data fusion architecture effectively achieve improved location and tracking accuracy.

Gene expression, which connects genomic information to functional units in living cells, has received substantial attention since the completion of The Human Genome Project. Quantitative characterization of gene expression will provide valuable information for understanding the behavior of living cells, and possibilities of building synthetic gene circuits to control or modify the behavior of naturally occurring cells. Many aspects of quantitative gene expression have been studied, including gene expression dynamics and noise in E. coli. The gene expression process itself is stochastic, and modelling approaches have been broadly used to study gene expression noise; however, stochastic gene expression models are usually large and time intensive to simulate. To speed up simulations, we have developed a systematic method to simplify gene expression models with fast and slow dynamics, and investigated when we can ignore the gene expression from the background genome when modelling the gene expression from plasmids. When modelling the noise in gene expression, one usually neglected aspect is the slow maturation process of fluorescent proteins, necessary for the protein to give out fluorescence after it is produced. By modelling, we show that the maturation steps can bring large changes to both the mean protein number and the noise in the model. An unstudied aspect of gene expression dynamics is the time dependent gene expression behavior in E. coli batch culture. Contrary to the usual assumption, we have found, in E. coli batch culture gene expression, that there is no steady state in terms of both the mean number of proteins and the noise. Negative feedback is thought to be able to reduce the noise in a system, and experiments have shown that negative feedback indeed suppresses the noise in gene expression, but the modelling shows that negative feedback will increase the noise. We have found that the increase of noise by feedback is due to the exclusion of extrinsic noise from the model, and that negative feedback will suppress the extrinsic noise while increasing the intrinsic noise. Living cells are crowded with macromolecules, which will, predicted by modelling, make the reaction constant time dependent. Our experimental observation has confirmed this prediction.

Gene expression, which connects genomic information to functional units in living cells, has received substantial attention since the completion of The Human Genome Project. Quantitative characterization of gene expression will provide valuable information for understanding the behavior of living cells, and possibilities of building synthetic gene circuits to control or modify the behavior of naturally occurring cells. Many aspects of quantitative gene expression have been studied, including gene expression dynamics and noise in E. coli. The gene expression process itself is stochastic, and modelling approaches have been broadly used to study gene expression noise; however, stochastic gene expression models are usually large and time intensive to simulate. To speed up simulations, we have developed a systematic method to simplify gene expression models with fast and slow dynamics, and investigated when we can ignore the gene expression from the background genome when modelling the gene expression from plasmids. When modelling the noise in gene expression, one usually neglected aspect is the slow maturation process of fluorescent proteins, necessary for the protein to give out fluorescence after it is produced. By modelling, we show that the maturation steps can bring large changes to both the mean protein number and the noise in the model. An unstudied aspect of gene expression dynamics is the time dependent gene expression behavior in E. coli batch culture. Contrary to the usual assumption, we have found, in E. coli batch culture gene expression, that there is no steady state in terms of both the mean number of proteins and the noise. Negative feedback is thought to be able to reduce the noise in a system, and experiments have shown that negative feedback indeed suppresses the noise in gene expression, but the modelling shows that negative feedback will increase the noise. We have found that the increase of noise by feedback is due to the exclusion of extrinsic noise from the model, and that negative feedback will suppress the extrinsic noise while increasing the intrinsic noise. Living cells are crowded with macromolecules, which will, predicted by modelling, make the reaction constant time dependent. Our experimental observation has confirmed this prediction.

Studien bygger på två 24 timmars ljudinspelningar utförda från två olika städer iSverige. Syftet med undersökningen var att se om det gick att urskilja akustiskaskillnader mellan två olika städer i Sverige. Studien har tagit mycket inspiration av R.Murray Schafer arbeten inom soundscaping, samt Pijanowskij, et al., (2011) ramverkför att kunna kategorisera ljuden utifrån dess ursprung och funktion. Olikaundersökningar har genomförts med hjälp av kvalitativa intervjuer, samtfrekvensanalyser av det inspelade materialet. Båda metoderna användes tillsammansvid utvärderandet av ljudmaterialet för att se hur vida informanternas svaröverrensstämde med den frekvensanalys som genomförts. Undersökningen visade attdet finns tydliga skillnader städerna emellan när det kommer till akustisk aktivitetoch intensitet. Däremot har båda städerna många likheter med varandra när detkommer till ljudinnehåll och ljudkällor. Studien skulle i framtiden kunna användasvid formandet av historiska ljudbibliotek för svenska städer.

Low-frequency noise (LFN) is characterized using in-house measurement systems in a variety of SiGe HBT generations. As technology scales to improve the performance and integration level, a large low-frequency noise variation in small geometry SiGe HBTs is first observed in 90 GHz peak fT devices. The fundamental mechanism of this geometry dependent noise variation is thought to be the superposition of individual Lorentzian spectra due to the presence of G/R centers in the device. The observed noise variation is the result of a trap quantization effect, and is thus best described by number fluctuation theory rather than mobility fluctuation theory. This noise variation continues to be observed in 120 GHz and 210 GHz peak fT SiGe HBT BiCMOS technology. Interestingly, the noise variation in the 210 GHz technology generation shows anomalous scaling behavior below about 0.2-0.3um2 emitter geometry, where the noise variation rapidly decreases. Data shows that the collector current noise is no longer masked by the base current noise as it is in other technology generations, and becomes the dominant noise source in these tiny 210 GHz fT SiGe HBTs. The proton response of LFN in SiGe HBTs is also investigated in this thesis. The results show that the relative increase of LFN is minor in transistors with small emitter areas, but significant in transistors with large emitter areas after radiation. A noise degradation model is proposed to explain this observed geometry dependent LFN degradation. A 2-D LFN simulation is applied to SiGe HBTs for the first time in order to shed light on the physical mechanisms responsible for LFN. A spatial distribution of base current noise and collector current noise reveals the relevant importance of the physical locations of noise sources. The impact of LFN in SiGe HBTs on circuits is also examined. The impact of LFN variation on phase noise is demonstrated, showing VCOs with small geometry devices have relatively large phase noise variation across samples.

The two-noise source model for predicting jet noise claims that the radiated jet noise is composed of two distinct sources one associated with the small-scale turbulence and another associated with the large-scale turbulence. The former source is claimed to radiate noise predominantly at larger angles with respect to the downstream jet axis, whereas the large-scale turbulence radiates predominantly at the shallower angles. A key objective of this effort is to experimentally validate this model using correlation and coherence measurements. Upon the successful validation of the two-noise source model for jets exhausting from multiple nozzle geometries driven at Mach numbers ranging from subsonic to supersonic, a three-microphone signal enhancement technique is employed to separate the contribution of the small-scale turbulence from that of the large-scale turbulence in the far-field. This is the first-ever quantitative separation of the contributions of the turbulence scales in far-field jet noise measurements. Furthermore, by suitable selection of far-field microphone positions, the separation of the contribution of any internal or core noise from that of the jet-mixing noise is achieved. Using coherence-based techniques to separate the contributions of the small-scale turbulence, large-scale turbulence, and any internal or core noise from far-field exhaust noise measurements forms the backbone of this effort. In the application of coherence-based multiple-microphone signal processing techniques to separate the contributions of the small-scale turbulence, large-scale turbulence, and any internal or core noise in the far-field, research efforts focus on three techniques (1) the coherent output power spectrum using two microphones, (2) an ordinary coherence method using the three-microphone technique, and (3) the partial-coherence method using five microphones. The assumption of jet noise incoherence between correlating microphone is included in each of these methods. In light of the noise radiation mechanisms described within the framework of the two-noise source model and their spatial characteristics as experimentally determined in the far-field, the assumption of jet noise incoherence is evaluated through a series of experiments designed to study jet noise coherence across a variety of nozzle geometries and jet Mach numbers ranging from subsonic to supersonic. Guidelines for the suitable selection of far-field microphone locations are established.

Abstract The advances of modern technology , creating a CPU and hardware speed greatly enhance the relative increase in number of work- ing temperature , so as not to make parts for high temperature, shortened life expectancy , we must take active cooling can be resolved , is gener- ated by the use of forced convection fan the heat away , but the fan noise when running , although not damage the hearing , have the potential to affect users of emotions ; as people increasingly rely on the computer, the fan gradually pay attention to the noise problem , so fans of R & D in recent years , in addition to increasing thermal efficiency , the increasing demands for noise. This article will examine the main centrifugal fan to AIO computer system for the experiment; AIO computer is the host and screen into one of the computer system, characterized by the internal space is small, heat is not easy, so the general would choose as the main centrifugal fan cooling fan, but the disadvantage of centrifugal fan noise is high, so this will do for the improvement of centrifugal fan noise research; to change the location of support ribs as the experimental setting, experimental method consists of three steps; first: Analog and down air inlet differences in velocity distribution, the second: the actual measurement centrifugal fan, is divided into single and measurement noise into the system and the sound quality of the judge, the third: performance testing; study showed that support rib in the middle of the design, the noise about 10% area reduction, sound quality also improved the effectiveness of nearly 50%, performance is also about 10% of the upgrade, the support rib in the middle of the design for double inlet centrifugal fans, for the better design.

An improved test system for acoustical rating of air-movement devices was installed and evaluated at the Riverside Energy Efficiency Laboratory at Texas A&M University where measurements of sound pressure levels were carried out using an array of six microphones instead of the existing rotating boom- microphone setup. The new array setup did not generate any inherent transient noise peaks, which provided adequate signal-to-noise ratios suitable for low sone fan testing. The reverberation chamber was qualified for broad-band testing in the frequency range 50 Hz to 10 kHz. Important acoustical parameters, namely, reverberation time and natural modes of the chamber, were determined. The purpose of this study was to identify potential background noise sources by computing the coherence functions between microphones placed outside the chamber and a microphone placed within the chamber. No strong coherence was observed, thus indicating adequate sound attenuation characteristics of the chamber walls. The effect of background noise levels on the loudness rating of fans was evaluated. A low sone fan and a louder fan (loudness greater than one sone) were tested during night time when the background noise is the least and during daytime and with the air conditioners running (high background noise level). While both fan types showed no significant change in loudness when tested during daytime and during the night, accurate ratings were not obtained with the air-conditioners running due to inconsistent spectrum. Finally, it was observed that with the six decibels separation requirement between the fan and background noise spectra for a low sone fan, at very low frequencies (below 63 Hz), despite inadequate fan- background separation, the loudness rating of the fan does not change as the minimum perceived loudness at these frequencies is very high. At very high frequencies (greater than 5 kHz), the fan does not generate any noise and hence the fan and the background noise sound pressure levels are very close to each other.

This study is based upon the vertical line array (VLA) in South China Sea experiment of the Asian Seas International Acoustic Experiment (ASIAEX), dated from May 3, 2001 to May 16, 2001, in which the ambient noise in shallow water was measured. In this paper, we use the beamforming method to calculate the vertical directionality of ambient noise in shallow water, for discussing the noise source distribution, and environmental effects on vertical directionality. The results show that distant shipping noise was observed near the horizontal angles, and surface noise occurred at high grazing angles. It is also discussed that the wind speed effect on the vertical directionality in this paper. Because of the typhoon Cimaron passed the experimental area during the experiment, which make wind speed changed obviously, so it can be found out the wind effect of ambient noise. By analyze the noise fluctuation, it is concluded that the threshold frequency of wind wave affected ambient noise levels were about 400 Hz. And after analyzing the vertical directionality, it is verified that the threshold was lower to 200 Hz. On the other hand, we also note the phenomena of ¡§noise notch¡¨ appeared at some duration when calculating the vertical directionality. The environmental effects (sound speed profile) on the notch, and the presentation of noise notch at different frequencies were discussed. In the end part of this paper, we determined the time when the notch occurred by using the power difference of vertical directionality, and we expect that the results would be important for similar researches in the future.