The rapid increase in the density of modern FPGAs has allowed ever increasingly complex designs to be mapped to FPGAs. However, this increase in logic resources is accompanied by an increase in the complexity of describing and verifying the operation of an application. This has prompted the search for new approaches to the design, debug and verification of circuits. The desire to find more effecient approaches to designing these large FPGA circuits has led to the creation of synthesizing compilers that can create hardware from high-level descriptions based on general purpose programming languages. Being able to describe the application at a high level of abstraction allows the designer to focus on the algorithms, rather than the implementation details. Though synthesizing compilers can make it easier to create circuits, they can make it more difficult to debug the resulting circuit. Typically, a design is debugged and verified by simulating the application/circuit in software (possibly at many different levels of abstraction). However, because of the reprogrammability of FPGAs, it is possible to use the FPGA device directly during the debug process. Performing design debug verification in the FPGA device has two significant advantages. First, the debugging occurs in the hardware itself and not a virtual abstraction. Second, debugging in hardware occurs at hardware speeds, which is orders of magnitude faster than software simulation. These two advantages make it possible to continue to verify large FPGA based designs.

In general the acoustic wave is used as a detecting tool in the ocean, its application placing a sound source into ocean, then the sound may impinge involves the target by wave propagation in the ocean. Due to the reflection and scattering effect of target, part of acoustic energy will be received by transducer through the path of reflection. The goal of target identification can be achieved by signal processing finally. If a submarine wish to avoid the detection by sonar system , it should attenuate the acoustic energy . Therefore the reflected signal can not be analyzed and distinguished by sonar system .The area of underwater acoustic attenuation has been researched for camouflaging submarine purpose for many years. There are two acoustic energy attenuation methods to reduce the reflective wave and transmitted wave. One is active attenuation control, which is to understand how the destructive interference of incident acoustic wave could be achieved for acoustic energy attenuation purposes. The other one is passive acoustic attenuation technique, which rely on the attenuation performance of underwater acoustic material to reduce the acoustic energy of incident wave. To be evaluated the acoustic absorption efficiency of material. Although the efficiency of active attenuation control is better compared with passive acoustic attenuation technique, the development of active attenuation control have not been highly pursued in the commercial market for underwater application, due to the limitations in piezo-composite technology. The cost of installation and maintenance is also higher in active control. This thesis studied the acoustic absorptive material based on passive acoustic attenuation technique . It could be attenuated the acoustic energy and spectrum of reflection and transmitted wave. Therefore, the signal can not be analyzed and distinguishing by sonar system. According to Alberich acoustic absorption coating, their designs have the inherent problem of degradation under hydrostatic pressure and temperature. Thus, the objective of this thesis is to study the characteristics of the acoustic absorptive material at various water depth where the hydrostatic pressure are different. To measure the characteristics of acoustic material, an experimental system is setup, and the standard measuring method and criterion is also studied for future experimental reference. Furthermore, the different measurement parameters are discussed for accuracy of experimental results. There are five specimens tested in this experiment. The specimens are mainly made of neoprene and sawdust mixture and marked as A1¡BA2¡BA3¡BA4¡Band A5 respectively. The composites of these specimens are analyzed by x-ray diffraction meter. The physical properties and the acoustic absorption in airborne were measured before underwater hydrostatic pressure applied on these specimens. The physical properties show that the impedance of these specimens is very close to acoustic impedance of the water. Therefore, the specimen may be considered an acoustic isolator in the air. To reduce the boundaries interference, such as reflection, diffraction and scattering signal. The pulse sound is used as sound source in this underwater experiment. Moreover, the gating system is applied to capture the proper signals for analysis. The echo reduction and insertion loss are measured in the 11 to 30 kHz frequency region for acoustic absorption evaluation in this experiment. The performance of experiment is found that specimen has the echo reduction about 10 dB and the insertion loss about 15 dB at 1 bar hydrostatic pressure. But when the hydrostatic pressure was increased to 5 bar, the echo reduction and insertion loss were both decreased by 3 dB. In addition, when the hydrostatic pressure was loaded at 10 bar, the echo reduction was decreased by 8 dB, and the insertion loss was decreased by 5 dB. It became evident that the efficiency of acoustic absorption is degraded under the higher hydrostatic pressure.

Male song and other acoustic signals are often sexually selected traits that are common in many taxa, such as birds, anurans and insects. Song often serves a dual function in female attraction and male-male competition and song characteristics such as duration, rate, repertoire size and amplitude are important for both functions and to be correlated with male reproductive success. Male humpback whales are well known for singing a complex and highly stereotyped song during the breeding season and while the song appears important in the social interactions of humpback whales during the breeding season, the function of song is still unclear. Current debate surrounds whether song is primarily directed towards females as an elaborate acoustic display or towards other males to facilitate male social ordering. The aim of this thesis was to investigate the nature of interactions between singers and conspecifics and document the context in which singing occurs. This was achieved by: (1) investigating the movement patterns and interactions between singing and non-singing whales and (2) examining differences in the song structure and source levels of song within a social context. To investigate song function, simultaneous observations of the positions and movements of singing and non-singing whales were obtained in real time during their southward migration off the east coast of Australia in September and October of 2002 - 2004. Data on the interactions of whales were collected by acoustic tracking using a hydrophone array, visual tracking using land-based hilltop observations and observations collected from a small boat. Of a total 114 singers, 48 did not associate with other whales whereas 66 were involved in 63 associations. Singers were significantly more likely to join groups containing a female and calf than any other group type and the only groups with which singers started to sing after joining were unescorted mother-calf pairs. Singers also associated for longer and sang for a significantly greater proportion of time in the presence of a female-calf pair than any other group type. Previous studies demonstrate that associating with females with a calf can be a reproductively successful strategy for males. In contrast, whales that joined singers were usually lone males, these associations were brief and singers typically stopped singing in the presence of other males. These findings provide the highest reported incidence in humpback whales of males singing when escorting females and support an intersexual function of song in humpback whales. A suggested explanation for observations of males joining singers is that these males are prospecting for females rather than engaging in male social ordering and that singing may incur the cost of attracting competing males. To investigate the importance of surface active behaviours in interactions involving singers and whether singers utilize the acoustic cues from these behaviours to locate other groups, the frequency and type of surface active behaviours were quantified in singing and non-singing groups. Compared to singers that were alone and did not interact with other whales, surrounding groups were significantly closer to a singer (on average 2.8 km distance) when singers joined other groups, and singers joined other groups that were surface active in 54 % of cases. While source levels of different surface active behaviours vary and certain behaviours might be better suited for inter-group communication, it is unlikely that singers rely primarily on acoustic cues from surface active behaviours to locate other groups. Surface activity was not more common in groups just prior to singers joining them, and while not significantly so, surface activity increased when singers affiliated with other groups suggesting an importance in intra-group dynamics. Whereas lone singers were the least surface active, groups containing a calf were found to exhibit a significantly higher rate of surface activity than groups without a calf, for which the calf displayed the majority of behaviours. Considering singers predominantly joined mother-calf pairs, it could be speculated that a high rate of surface activity by a calf might inadvertently attract singers and other surrounding males to these groups and could increase the probability of singers and other males locating mother-calf groups. To further explore a context of singing, the structure and amplitude of songs were investigated over two years for singers in two distinct social contexts; lone singers and singing escorts. A total of 274 songs from 27 singers in 2003 and 2004 were analysed, with a subset of data used for source level comparisons. Lone singers consistently sang longer songs compared to singing escorts due to a greater repetition of phrases most noticeably within one theme (theme C), the theme in which all singers sang the most common song unit (the moan) at higher amplitude compared to the other three themes in which it occurred. These findings suggest that lone singers might increase the repetition of phrases sung at higher amplitude to maximise the broadcast of their song and maximise their probability of detection. In contrast, singing escorts sang shorter songs due to a reduced repetition of phrases in most themes, particularly the theme containing the loudest song units (theme C). Consequently, singing escorts sang the song more quickly, resulting in a higher song rate compared to lone singers. Comparisons of the average broadband source levels of nine song units in the 2004 song showed significant variation among the nine different units and among the 22 individual singers for each song unit. Source levels of one of the nine song units also varied significantly between lone singers and singing escorts. Singing escorts produced higher source levels than lone singers for the ‘cry’ which showed a difference of 4 dB higher than lone singers. Lone singers typically produced higher source levels for the ‘moans’, which were low frequency sounds that propagate well, although this was not significant. We suggest that amplitude of the song might be important in female assessment of singers and the particular song units that singing escorts sing more loudly are the basis for this assessment. These findings further support an inter-sexual function of song in humpback whales. This study has described in detail the contexts in which males are observed to sing and has been able to provide new interpretations on the social interactions of singers. The results within this thesis provide the highest reported occurrence in humpback whales of males singing in the presence of females and strongly suggest that song has an inter-sexual function. Further work is needed that investigates song structure within a social context and the potential for song functioning as a long distance advertisement display and/ or courtship display.

Stencil computations are iterative kernels often used to simulate the change in a discretized spatial domain overtime (e.g., computational fluid dynamics) or to solve for unknowns in a discretized space by converging to a steady state (i.e., partial differential equations).They are commonly found in many scientific and engineering applications. Most stencil computations allow tile-wise concurrent start ,i.e., there exists a face of the iteration space and a set of tiling hyper planes such that all tiles along that face can be started concurrently. This provides load balance and maximizes parallelism. Loop tiling is a key transformation used to exploit both data locality and parallelism from stencils simultaneously. Numerous works exist that target improving locality, controlling frequency of synchronization, and volume of communication wherever applicable. But, concurrent start-up of tiles that evidently translates into perfect load balance and often reduction in frequency of synchronization is completely ignored. Existing automatic tiling frameworks often choose hyperplanes that lead to pipelined start-up and load imbalance. We address this issue with a new tiling technique that ensures concurrent start-up as well as perfect load balance whenever possible. We first provide necessary and sufficient conditions on tiling hyperplanes to enable concurrent start for programs with affine data accesses. We then discuss an iterative approach to find such hyperplanes. It is not possible to directly apply automatic tiling techniques to periodic stencils because of the wrap-around dependences in them. To overcome this, we use iteration space folding techniques as a pre-processing stage after which our technique can be applied without any further change. We have implemented our techniques on top of Pluto-a source-level automatic parallelizer. Experimental evaluation on a 12-core Intel Westmere shows that our code is able to outperform a tuned domain-specific stencil code generator by 4% to2 x, and previous compiler techniques by a factor of 1.5x to 15x. For the swim benchmark from SPECFP2000, we achieve an .improvement of 5.12 x on a 12-core Intel Westmere and 2.5x on a 16-core AMD Magny-Cours machines, over the auto-parallelizer of Intel C Compiler.