Map estimation of air-flow dipole source positions using array signal processing

In nature, fish have the ability to form flow-based maps to assist localizing predator or prey using the lateral-line system. Yet it is not fully understood what techniques are used by fish to draw these flow maps. Biologists try to figure out fish techniques by investigating different hypotheses [1]. Inspired by the lateral line of fish, we propose in this paper model based array signal processing techniques used to visualize the air-flow maps. The results show an ability to visualize the flow field generated by a dipole source using lateral-line system

Interfacing of artificial hairs array for complex flow pattern recognition

In this paper we report on the latest developments in characterising and interfacing biomimetic flow-sensor array based on the flow sensitive mechano-sensors of crickets. Capacitive hair sensors have been fabricated using a surface micromachining technology and implemented to detect air flows. We have realized readout electronics to detect the movements capacitively using electrodes integrated on the membrane. A charge amplifier, which produces an output voltage representing the capacitance variation of the selected sensor, is used to pick up the signal. An array of hair sensors is implemented for better and more representative flow signals compared to single sensor measurement. Different schemes for measuring individual sensors in arrays independently are discussed. Frequency Division Multiplexing is found to be efficient for this purpose individual element measurement.\ud Key Words: Artificial hairs, capacitive readout, FD

On the Use of Various Oscillatory Air Flow Fields for Characterization of Biomimetic Hair Flow Sensors

To determine the characteristics of flow sensors, a suitable source for flow generation is required. We discuss three different sources for oscillating air flow, by considering their acoustic impedance, frequency range, velocity and ability to distinguish between flow and pressure. We discuss the impact of these sources on characterization of our biomimetic hair flow sensors, which operate at flow velocities from 1–100 mm/s within a frequency range from 10–1000 Hz

Khaled Hosseini’s A Thousand Splendid Suns as a Child-Rescue and Neo-Orientalist Narrative

In their article Khaled Hosseini\u27s A Thousand Splendid Suns as a Child-Rescue and Neo-Orientalist Narrative Abdullah Mohammad Dagamseh and Olga Golubeva argue that the novel contrib­utes to hegemonic Eurocentric discourse by showing the superiority and benevolence of the West. In contrast to existing scholarly focus on Hosseini\u27s portrayal of female characters, this article highlights how children of both sexes are represented. The authors\u27 aim is to show how Hosseini\u27s picture of children affected by war contributes to the neo-Orientalist and child-rescue discourses, jus­tifying the foreign involvement in Afghanistan\u27s internal affairs. Moreover, Dagamseh and Golubeva argue that the use of universal values and the seemingly noble cause of bettering the lives of children in Afghanistan contribute to the stereotypical discourse of a progressive West and an underdevel­oped East

Array of Biomimetic Hair Sensor Dedicated for Flow Pattern Recognition

Flow sensor arrays can be used to extract features from flow fields rather than averaging or providing local measurements provided the sensors in the array structure can be interrogated individually. This paper addresses the latest developments in fabrication and array interfacing of biomimetic artificial air-flow sensors. Hair flow sensors in wafer level arrays have been successfully fabricated using SOI wafers with deep trench isolation structures. Using a Frequency Division Multi¬plexing (FDM) technique, we were able to simultaneously measure flow signals at multiple sensor positions. By virtue of FDM, once signals are retrieved from all individual array elements, spatio-temporal flow patterns can be reconstructed, while few system interconnects are required

Thermal noise estimation in bio-inspired hair flow sensor

In micromachining technology, the reduction in the size of the moving structures has many advantages in different applications. However, these moving structures are subjected to mechanical noise resulting from the molecule agitation. In this abstract, we investigate the thermal-mechanical noise in our artificial hair-flow sensor. The realization of such sensors with high sensitivities requires designs with both low thermal-mechanical noise and high-resolution of angular displacement

A simulation study of the dipole source localisation applied on bio-mimetic flow-sensor linear array

In flow-sensor arrays, elements are distributed at different positions and each sensor locally constructs the flow field components. In this paper, we report the developments of the bio-inspired artificial flow-sensors in array structures. The source localisation mechanism in fish, using the flow pattern generated from prey, is modelled. We computed the flow velocity components (parallel and perpendicular), generated by a dipole source, at the array position and based on the structure of our flow sensor. The ability of our sensors, arranged in arrays, to detect flow patterns was investigated. The model results were found to be in an excellent agreement with the measurements along virtual lateral-line and successfully demonstrate the source-distance determination

A two-stage power amplifier design for ultra-wideband applications

In this paper, a two-stage 0.18 μm CMOS power amplifier (PA) for ultra-wideband (UWB) 3 to 5 GHz based on common source inductive degeneration with an auxiliary amplifier is proposed. In this proposal, an auxiliary amplifier is used to place the 2nd harmonic in the core amplified in order to make up for the gain progression phenomena at the main amplifier output node. Simulation results show a power gain of 16 dB with a gain flatness of 0.4 dB and an input 1 dB compression of about -5 dBm from 3 to 5 GHz using a 1.8 V power supply consuming 25 mW. Power added efficiency (PAE) of around 47% at 4 GHz with 50 Ω load impedance was also observed

Language maintenance, shift and variation evidence from Jordanian and Palestinian immigrants in Christchurch New Zealand.

There has been a substantial amount of research on language maintenance and shift (LMLS) and language variation and change (LVC) in New Zealand in the last four decades and most of this research has concentrated on exploring LMLS separately from LVC. Most researchers deal with these two topics as two different fields. For example, if they study LMLS (e.g., proficiency, domains and attitudes), they don’t focus on the speaker’s production of a language (e.g., vowels and consonants) within the same thesis. This thesis combined both LMLS and LVC in one thesis by employing questionnaires which were gathered from 99 Arab Jordanians and Palestinians to answer three research questions related to LMLS. The first research question related to reported language proficiency and the influence of generation (1st, 1.5 and 2nd) and length of residence (1- 10 years, 11-20 years and 21-30 years) on that. The second research question looked at language use in different domains (e.g., home, friendship and religion) and the influence of generation and length of residence on that. The third research question examined the participants’ attitudes towards both Arabic and English languages in general and New Zealand English (NZE) in particular and cultures and the influence of generation and length of residence on that. 20 of the survey participants who expressed willingness to be interviewed, subsequently participated in recorded interviews, which were used to investigate the realisation of particular consonants (ING and intervocalic /t/ and NZE short front vowels (KIT, DRESS and TRAP) in the speech of Jordanians and Palestinians in Christchurch New Zealand. The interviews aimed to answer four research questions. Two research questions related to the consonants (whether social factors influence the production of these two consonants and whether attitudes collected by questionnaire predict any of the linguistic behavior), and two questions related to the vowels (whether social factors and lexical frequency influence the production of these three vowels, and whether attitudes collected by questionnaires predict any of the linguistic behavior for these vowels). By combining work in language maintenance and shift with work in language variation and change, this thesis aimed to reveal patterns which could be masked when each question was investigated separately. This is because LMLS and LVC are both driven in part by attitudes. I linked speakers’ attitudes in the questionnaires to their linguistic behavior and examined the influence attitudes have on the production of the variables ING, intervocalic /t/, KIT, DRESS and TRAP. The interviews also provide some explanations for the attitudinal significant correlations found in the questionnaire and in their productions of the five variables examined. Principal component analysis (PCA) was used to find underlying attitudinal categories from the answers and build up an attitudinal index score for each speaker. The scores were used to evaluate the attitudes of one speaker compared to another toward Arabic language and culture and English language and New Zealand culture. The results for the LMLS part of the study showed that there is a gradual language shift in all domains (e.g., home, friends and religion), most sharply in the friends domain, then religion and finally home domain among 1.5 and 2nd generations and 11-20 and 21-30 length of residence. In addition, clear regression in Arabic literacy skills among 1.5 and 2nd generations and those who have been in NZ between 11-20 years was found. However, the attitudinal results showed that Arabic Jordanians and Palestinians in Christchurch are very loyal and positive towards their ethnic language because it is intertwined with their Islamic religion and culture. They also showed positive attitudes towards English in general and New Zealand English (NZE) and culture in particular, due to its perceived usefulness as well as its status in the world. The LVC part of the study used mixed effects logistic regression modelling to analyse the influence of different factors on the production of ING and intervocalic /t/. The study identified three possible variants for the ING variable in the Jordanians and Palestinians speech of English [ɪŋ], [ɪn] and [ɪŋɡ]. The variable ING patterns were similar to NZE in the production of the younger generations (2nd and 1.5). However, the older generation (1st generation) showed a mixture between prototypical NZE patterns and typical Jordanian Arabic realisations. The 1st generation was likely not to have completely acquired the NZE variants of the variable ING. Female speakers were more likely to produce more native-like ING features than males. Length of residence was also significant, with those who have been living in New Zealand between 11 to 20 years producing more NZE variants than other groups. Occupation also played a role, with ‘in-work’ speakers using more NZE variants than ‘not in-work’ speakers. The analysis showed that there was a significant positive correlation between Principal Component (PC2) (attitudes toward English) and the production of the NZE variants of ING. The results are discussed in light of positive vs negative attitudes, instrumental vs integrative attitudes and identity. For intervocalic /t/ three possible variants were identified across Jordanian and Palestinian speakers in Christchurch (CANONICAL /t/, FLAP and GLOTTAL STOP) and social factors were found to play a significant role. For example 2nd generation participants produced the most FLAP and GLOTTAL STOP realisations, those who have been living in the country from 11-20 and 21-30 years were found to produce the most FLAP, while 1st generation participants and those who have been living in NZ from 1-10 years produced significantly more CANONICAL /t/. Attitudes were not found to have any significant bearing on the production of the intervocalic /t/ variants. The other three linguistic variables investigated in the thesis were the three NZE short front vowels KIT, DRESS and TRAP, where I tried to determine if the speakers had adopted the shift happening in these three NZE vowels and investigated the effect of social variables such as generation, gender, word frequency and attitude on the speaker’s production of these vowels. A mixed effects model was used to analyse the influence of these factors on the vowels. The results showed that the social factors: generation, attitudes, word frequency and gender were significant factors affecting Jordanian speakers’ production of the three NZE short front vowels. Significant differences were found for DRESS F1, TRAP F1, TRAP F2, KIT F1 and KIT F2. The results also provide evidence for vowel shift in L2 speakers for the three NZE short vowels (KIT, DRESS and TRAP), particularly among 1st and 1.5 generations more than the 2nd generations. Attitudes were significant with DRESS F1, TRAP F2 and KIT F2 and discussed deeply in the thesis. Finally, the qualitative attitudinal results in the interviews offered some explanations for the consonant and the vowel results and matched them to the linguistic behavior (production of the vowels and consonants). Overall, the results provided evidence that attitudes can link both LMLS and LVC and that the quantitative attitudinal results from the questionnaire likely match with the qualitative attitudinal results from the interviews and all are likely to predict linguistic behavior. The findings also suggest that the role attitudes play in LMLS and LVC can be very complex

Artificial lateral-line system for imaging dipole sources using Beamforming techniques

AbstractIn nature, fish have the ability to localize prey, school, navigate, etc. using the lateral-line organ [1]. Here we present the use of biomimetic artificial hair-based flow-sensors arranged as lateral-line system in combination with beamforming techniques for dipole source localization in air. Modelling and measurement results show the artificial lateral-line ability to image the position of dipole sources accurately. Such systems open possibilities for flow-based near-field environment mapping which can be beneficial e.g. to robot guidance applications