High-level Input Research Articles

Wind noise in hearing aids: I. Effect of wide dynamic range compression and modulation-based noise reduction

Objective: The objectives of this study were: (1) to examine the effect of wide dynamic range compression (WDRC) and modulation-based noise reduction (NR) algorithms on wind noise levels at the hearing aid output; and (2) to derive effective strategies for clinicians and engineers to reduce wind noise in hearing aids. Design: Three digital hearing aids were fitted to KEMAR. The noise output was recorded at flow velocities of 0, 4.5, 9.0, and 13.5 m/s in a wind tunnel as the KEMAR head was turned from 0° to 360°. Study sample: Flow noise levels were compared between the 1:1 linear and 3:1 WDRC conditions, and between NR-activated and NR-deactivated conditions when the hearing aid was programmed to the directional and omnidirectional modes. Results: The results showed that: (1) WDRC increased low-level noise and reduced high-level noise; and (2) different noise reduction algorithms provided different amounts of wind noise reduction in different microphone modes, frequency regions, flow velocities, and head angles. Conclusions: Wind noise can be reduced by decreasing the gain for low-level inputs, increasing the compression ratio for high-level inputs, and activating modulation-based noise reduction algorithms.

Towards High-Fidelity Machining Simulation

The main purpose of any machining simulation system is to reveal or mimic the real machining process as accurately as possible. Current simulation systems often use G-code or CL data as input that has inherent drawbacks such as vendor-specific nature, incomplete data, irreversible data conversions and lack of accuracy. These limitations hinder the development of a truthful simulation system. Hence, there is a need for higher-level input data that can assist with accurate simulation for machining processes. In addition, there is also a need to take into account of true behaviour and real-time data of a machine tool. The paper presents a High-Fidelity Machining Simulation solution for more accurate results. STEP-NC is used as the input data as it provides a more complete data model for machining simulations. The status-quo of the machine tool is captured by means of sensors to provide true data values for machining simulation purposes. The outcome of the research provides a smart and better informed simulation environment. The paper reviewed some of the current simulation approaches, highlighted the current simulation problems, discussed input data sources for smart machining simulation and introduced the high-fidelity simulation system architecture.

Knowledge through participation: the triumphs and challenges of transferring Integrated Pest and Disease Management (IPDM) technology to cocoa farmers in Papua New Guinea

Income from cocoa is the main source of cash used to purchase food and services in many communities in the tropical lowlands of Papua New Guinea (PNG). Despite the availability of improved management technology, there has been poor transfer and uptake of these technologies among smallholder cocoa farmers, and potentially high bean yields and farmer incomes remain unrealised. A series of IPDM options that were shown to improve crop management and cocoa bean yield in research trials were demonstrated to farmers using an on-farm participatory approach that enabled farmers to evaluate the costs and benefits of each strategy before committing to adoption. The options were designed to provide several levels of entry to improved management, and ranged from no inputs (Option 1), manual inputs (Option 2: pruning, sanitation, weed management and regular complete pod harvesting), high level inputs (Option 3: pruning, sanitation, weed management, regular complete pod harvesting and fertiliser application), to intensive management (Option 4: pruning, sanitation, weed management, regular complete pod harvesting, and the application of fertiliser, fungicide and pesticide). Farmers from East New Britain, Madang and Bougainville, the three main cocoa growing provinces in PNG, participated in on-farm IPDM training and surveys to monitor changes in knowledge and management practice. Farmers opted in or out of the training as their commitments or level of interest changed, and new farmers joined in after observing changes in the cocoa blocks. Farmers were trained in epidemiology and crop management, were shown how to apply the IPDM inputs in their own cocoa blocks, and were given a simple training manual. Surveys conducted prior to, and 3 years after the training, showed an improvement in the farmers’ knowledge of cocoa management and a better understanding of cocoa pest and disease epidemiology. Three years after the training, pest and disease incidence in participating cocoa blocks had declined and cocoa yields had increased by an average of 30%. Trained farmers were encouraged to demonstrate improved management to neighbouring farmers, and the program has now been officially adopted as the national strategy to improve cocoa production in PNG. The participatory approach is an effective way of disseminating information and technology to farmers, however, it requires frequent follow-up visits by trained extension staff. We also discuss the significant challenges associated with conducting farmer surveys.

Procedural animation for glove puppet show

Traditional Taiwanese glove puppet show is a unique form of performing art. We aim to use the aid of computer animation technologies to preserve this cultural heritage and create innovative ways of performance. By observing the demonstration of a puppet master, we analyse the characteristics of how a hand puppet is manipulated and design animation procedures mimicking the motion of a glove puppet. These procedures are implemented on a real-time animation platform for procedural animation. Through the system, we allow a user to perform glove puppet animation with high-level inputs. We hope that, with the help of this system, not only the art of manipulating a glove puppet can be systematically documented, but also the entry barrier for learning it can also be greatly reduced.

Simulation of gain and timing resolution in saturated pores

Micro-channel plate (MCP) amplifiers are commonly used in detectors of fast time signals with picosecond resolution. The main parameters of the MCP amplifier, such as the gain factor and time resolution are strongly dependent on the work regime of the device. The saturation effects occur with a high-level input signal. In our paper these effects are studied numerically for large-area fast photo-detectors. It is shown that the saturation effect for short pulses can be reduced by introducing a thin, resistive layer between the bulk material and the emissive coating. A set of 2D and 3D numerical tools (MCP simulator, Monte Carlo simulator) was developed to simulate photo, secondary emission, fringe fields, and saturation phenomena in MCP amplifiers. The gain and time resolution dependencies on the pore size and voltage were studied numerically. The results are compared with the simulations of other authors and available experimental data.

Realizing Model Transformation Chain interoperability

A single Model Transformation Chain (MTC) takes a high-level input model rooted in the problem domain and through one or more transformation steps produces a low-level output model rooted in the solution domain. To build a single "almighty" MTC that is in charge of every design, implementation and specific platform concern is a complex task. Instead, we can use several smaller MTCs that are easier to develop and maintain, because each MTC is independently developed focusing on a specific concern. However, the MTCs must interoperate to produce complete applications; this inherently creates dependencies between them, because each MTC generates a part of the final low-level model. In this paper, we propose an external and explicit mechanism to track dependencies between the MTCs (i.e., the MTCs are oblivious to the mechanism), which is used to automatically derive correspondence relationships between the final models generated by each MTC. The contribution of our mechanism is the reduction of complexity of building interoperable MTCs because the derived correspondences are resolved after the transformations execution, in the solution domain where the semantics of every concept is well-defined. The resolution process consists of (1) checking the consistency between the models, (2) producing communication bridges or (3) guiding the composition of the models. This paper presents three case studies to illustrate the derivation and resolution of correspondence relationships through the MTCs.

The role of recollection and familiarity in the functional differentiation of the medial temporal lobes

The components of the medial temporal lobes (MTL) receive different kinds of input. The perirhinal cortex receives primarily object/item information, the parahippocampal cortex receives contextual information, and the hippocampus receives high-level inputs that include object/item, context, and other information. Critically, the perirhinal and parahippocampal cortices have similar cytoarchitectonics, which differ considerably from that of the hippocampus and suggest that these cortices process their inputs differently from the way that the hippocampus processes its inputs. Much evidence indicates that the hippocampus is designed to rapidly bind together pattern-separated representations that support recall/recollection well. In contrast, the newer MTL cortices rapidly create poorly pattern-separated memories that support familiarity well, but recall/recollection very poorly. For over a decade, there has been disagreement about whether recall/recollection is primarily mediated by the hippocampus and familiarity by the evolutionarily newer MTL cortices or whether the MTL mediates these kinds of memory in an integrated, homogeneous fashion. Common misconceptions about familiarity, recollection, item, and associative memory are discussed as are methodological problems with MTL lesion and functional imaging research. The possible confound of familiarity with weaker memory and recollection with stronger memory is discussed and the implications of the Montaldi et al. (2006) functional Magnetic Resonance Imaging (fMRI) study, which matched memory strength between strong familiarity and recollection, finding that only recollection activated the hippocampus, are discussed. A suggestion is made about how the long-running conflict of findings in the human hippocampal lesion literature may be resolved.

Programming hearing instruments to make live music more enjoyable

Programming hearing instruments to make live music more enjoyable

Oscillation-controlled CMOS ring oscillator for wireless sensor systems

This paper presents a ring oscillator with the function of the oscillation controlled for wireless sensor systems (WSSs). The proposed oscillator consists of a NAND gate, 4 inverters, and 1-, 3-, 9-times buffer stage. Operation of it is controlled by the NAND gate. The oscillator can reduce the power loss because the oscillator is oscillated during only high level input. The proposed oscillator was designed and fabricated by 2.5μm CMOS technology, through which it is possible to realize a WSS on a single chip because a sensor and an oscillator can be fabricated concurrently.The frequency tuning range of the oscillator was found to be approximately 90–152MHz and the output power of the oscillator was −8.42dBm. The measured phase noise is −99.35 and −102.59dBc/Hz at 1 and 5MHz offsets, respectively, from the carrier of 152MHz. Power consumption of the oscillator is determined by the duty cycle of the input signal pulse, and the range of power consumption was measured as 1.5–45mW at the duty cycle of 1.0.

Tactics for Hierarchical Proof

There is something of a discontinuity at the heart of popular tactical theorem provers. Low-level, fully-checked mechanical proofs are large trees consisting of primitive logical inferences. Meanwhile, high-level human inputs are lexically structured formal texts which include tactics describing search procedures. The proof checking process maps from the high-level to low-level, but after that, explicit connections are usually lost. The lack of connection can make it difficult to understand the proof trees produced by successful tactic proofs, and difficult to debug faulty tactic proofs. We propose the use of hierarchical proofs, also known as hiproofs, to help bridge these levels. Hiproofs superimpose a labelled hierarchical nesting on an ordinary proof tree, abstracting from the underlying logic. The labels and nesting are used to describe the organisation of the proof, typically relating to its construction process. In this paper we introduce a foundational tactic language Hitac which constructs hiproofs in a generic setting. Hitac programs can be evaluated using a big-step or a small-step operational semantics. The big-step semantics captures the intended meaning, whereas the small-step semantics is closer to possible implementations and provides a unified notion of proof state. We prove that the semantics are equivalent and construct valid proofs. We also explain how to detect terms which are stuck in the small-step semantics, and how these suggest interaction points with debugging tools. Finally we show some typical examples of tactics, constructed using tactical combinators, in our language.

PCBs and DDE, but not PBDEs, increase with trophic level and marine input in nestling bald eagles

Concentrations of persistent contaminants often vary widely among individuals within a population. We hypothesized that such variation was caused mainly by differences in diet (biomagnification) and in coastal systems by the tendency of marine systems to act as contaminant sinks. We examined the relationship between contaminant concentrations and stable isotope ratios in nestling plasma from an apex predator with a particularly broad diet. Our study included freshwater, estuarine, inshore and pelagic breeding sites. Bald eagles ( Haliaeetus leucocephalus) at the pelagic marine sites showed high trophic level and marine input, eagles at the freshwater sites showed low trophic level and marine input, and eagles at the estuarine and inshore marine sites had intermediate values. The relationship between trophic level and marine input may reflect longer food chains in pelagic compared to terrestrial ecosystems. ∑PCBs and DDE concentrations generally increased with trophic level and marine input, with the exception of the freshwater sites, while ∑PBDEs, hydroxylated-PBDEs and hydroxylated-PCBs increased with marine input, but were independent of trophic level. The relationships for ∑PCBs and DDE were often slightly stronger with marine input than trophic level, suggesting that oceanographic processes may be more important than trophic level. At freshwater locations, spatial variation may be more important than trophic level due to the heterogeneity of contaminant profiles between feeding locations (lakes, rivers, agricultural fields). Adults had similar isotopic composition to their chicks but higher contamination. Based on nests where prey composition was determined independently, isotopic enrichment values for nestling plasma were 1.6 ± 0.1 ( δ 15N) and − 0.4 ±0.2 ( δ 13C). We conclude that trophic level and marine influence are significant factors influencing PCB and DDE concentrations in eagles. However, trophic level in particular did not influence PBDEs, possibly due to their being metabolized by eagles.

Automated Code Generation for Discontinuous Galerkin Methods

A compiler approach for generating low-level computer code from high-level input for discontinuous Galerkin finite element forms is presented. The input language mirrors conventional mathematical notation, and the compiler generates efficient code in a standard programming language. This facilitates the rapid generation of efficient code for general equations in varying spatial dimensions. Key concepts underlying the compiler approach and the automated generation of computer code are elaborated. The approach is demonstrated for a range of common problems, including the Poisson, biharmonic, advection-diffusion, and Stokes equations.

A novel open CNC architecture based on STEP-NC data model and IEC 61499 function blocks

Modern manufacturing industries demand computer numeric controllers, having higher level input languages than outdated G-code, and less proprietary vendor dependencies. IEC 61499 is a new standard for distributed measurement and control systems, that enables portability and interoperability of embedded controllers, along with the ease of their mapping to arbitrary distributed networking hardware configurations. This paper demonstrates that the IEC 61499 reference architecture can be successfully used to create a computer numeric controller, offering interoperability, portability, configurability, and distribution characteristics. The layered CNC-FB architecture is proposed, which simplifies the design of a CNC machine controller with the architecture layers responsible for data processing, data storage and execution. In combination with the object-oriented Model-View-Control design pattern, the CNC-FB architecture supports the design framework, in which simulation of the machining becomes natural and inherent part of the design process, with seamless transition from simulation to actual machining. The implemented controller was tested in both the model and on an actual milling machine.

Multichannel Compression Hearing Aids: Perceptual Considerations

Multichannel Compression Hearing Aids: Perceptual Considerations

Novel room-temperature functional analogue and digital nanoelectronic circuits based on three-terminal ballistic junctions and planar quantum-wire transistors

Three-Terminal ballistic junctions (TBJs) and planar quantum-wire transistors (QWTs) are emerging nanoelectronic devices with various novel electrical properties. In this work, we realize novel nanoelectronic analogue and digital circuits with TBJs and planar QWTs made on In0.75Ga0.25As/InP two-dimensional electron gas (2DEG) material. First we show that a single TBJ can work as a frequency mixer or a phase detector. Second, we fabricate an integrated nanostructure containing two planar QWTs, which can be used as an RS flip-flop element. Third, we make a nanoelectronic circuit by the integration of two TBJs and two planar QWTs. This circuit shows the RS flip-flop functionalities with much larger noise margins in both high and low level inputs. All measurements in this work are done at room temperature.

Adaptive feedback cancellation in hearing aids with clipping in the feedback path

Adaptive linear filtering algorithms are commonly used to cancel feedback in hearing aids. The use of these algorithms is based on the assumption that the feedback path is linear, so nonlinearities in the feedback path may affect performance. This study investigated the effect on feedback canceller performance of clipping of the feedback signal arriving at the microphone, as well as the benefit of applying identical clipping to the cancellation signal so that the cancellation path modeled the nonlinearity of the feedback path. Feedback signal clipping limited the amount of added stable gain that the feedback canceller could provide, and caused misadjustment in response to high-level inputs, by biasing adaptive filter coefficients toward lower magnitudes. Cancellation signal clipping mitigated these negative effects, permitting higher amounts of added stable gain and less misadjustment in response to high-level inputs, but the benefit was reduced in the presence of the highest-level inputs.

Low-frequency and high-frequency cochlear nonlinearity in humans.

Low- and high-frequency cochlear nonlinearity was studied by measuring distortion product otoacoustic emission input/output (DPOAE I/O) functions at 0.5 and 4 kHz in 103 normal-hearing subjects. Behavioral thresholds at both f2's were used to set L2 in dB SL for each subject. Primary levels were optimized by determining the L1 resulting in the largest L(dp) for each L2 for each subject and both f2's. DPOAE I/O functions were measured using L2 inputs from -10 dB SL (0.5 kHz) or -20 dB SL (4 kHz) to 65 dB SL (both frequencies). Mean DPOAE I/O functions, averaged across subjects, differed between the two frequencies, even when threshold was taken into account. The slopes of the I/O functions were similar at 0.5 and 4 kHz for high-level inputs, with maximum compression ratios of about 4:1. At both frequencies, the maximum slope near DPOAE threshold was approximately 1, which occurred at lower levels at 4 kHz, compared to 0.5 kHz. These results suggest that there is a wider dynamic range and perhaps greater cochlear-amplifier gain at 4 kHz, compared to 0.5 kHz. Caution is indicated, however, because of uncertainties in the interpretation of slope and because the confounding influence of differences in noise level could not be completely controlled.

OpenSESAME—the simple but extensive, structured availability modeling environment

This article describes the novel stochastic modeling tool OpenSESAME which allows for a quantitative evaluation of fault-tolerant High-Availability systems. The input models are traditional reliability block diagrams (RBDs) which can be enriched with inter-component dependencies like failure propagation, failures with a common cause, different redundancy types, and non-dedicated repair. OpenSESAME offers a novel set of graphical diagrams to specify these dependencies. Due to the dependencies, traditional solution methods for RBDs cannot be applied to OpenSESAME models. We therefore present a novel evaluation method, which is based on the automatic generation of several state-based models, which are semantically equivalent to the high-level input model. Alternatively, either stochastic Petri nets or textual models based on a stochastic process algebra can be generated. The state-based models are then analyzed using existing solvers for these types of models. Three case studies exemplify the modeling power and usability of OpenSESAME.

Correction of the Peripheral Spatiotemporal Response Pattern: A Potential New Signal-Processing Strategy

The purpose of this paper is to introduce a new signal-processing strategy, spatiotemporal pattern correction (SPC), that is based on our knowledge of the level-dependent temporal response properties of auditory nerve fibers in normal and impaired ears. In normal-hearing listeners, tuning is sharp for low-level inputs and broadens as input level increases. When peripheral filters change their shape with input level, the phase properties of the filters and the latency of the filter's response also change. However, in listeners with hearing loss, tuning is broad for both low- and high-level inputs. Thus, there is little change in the phase properties of the filters for different input levels. The SPC strategy manipulates the temporal aspects of different frequency channels of sounds in an attempt to "correct" for this abnormal spatiotemporal response pattern of the impaired ear. Quality judgments and intelligibility measures of speech processed at various SPC strengths were obtained from a small group of normal-hearing listeners and listeners with hearing loss. In general, listeners with hearing loss preferred sentences with some degree of SPC processing, whereas normal-hearing listeners preferred unprocessed sentences. Benefit from SPC on the nonsense syllable test varied greatly across phonemes and listeners. A more comprehensive study of listeners with different degrees and configurations of hearing loss is needed to determine the amount of SPC benefit.

Impacts of reduced sulfur components on active and resting ammonia oxidizers.

While there has been significant research on the nature and extent of the impact of inhibitory reduced sulfur with respect to anaerobic (e.g., methanogenic and sulfidogenic) microbial systems, only limited study has yet been conducted on the comparable effects of soluble sulfides which might occur within aerobic wastewater treatment systems. Admittedly, aerobic reactors would not normally be considered conducive to the presence of reduced sulfur constituents, but there do appear to be a number of processing scenarios under which related impacts could develop, particularly for sensitive reactions like nitrification. Indeed, the following scenarios might well involve elevated levels of reduced sulfur within an aerobic reactor environment: (1) mixed liquor recycle back through sulfide-generating anaerobic zones (e.g., in conjunction with biological nutrient removal processes, etc.), (2) high-level side-stream sulfide recycle via sludge digestion, etc., back to aerobic reactors, and (3) high-level influent sulfide inputs to wastewater treatment facilities via specific industrial, septage, etc., streams. The objective of this study was, therefore, to determine the subsequent metabolic impact of soluble sulfide under aerated and unaerated conditions, focusing in particular on ammonia-oxidizing bacteria due to their critical first-step role with nitrification. The obtained results indicated that, under catabolically active conditions, cultures of ammonia oxidizers were extremely sensitive to the presence of sulfide. At total soluble sulfide concentrations of 0.25 mg l(-1) S, active ammonia oxidation was completely inhibited. However, immediately following the removal of this soluble sulfide presence, ammonia oxidation started to recover; and it continued to improve over the next 24 h. Similar sulfide impact tests conducted with inactive ammonia oxidizers exposed during anaerobic conditions, albeit at higher dosage levels, also revealed that their subsequent aerobic activity would correspondingly be retarded. These results indicated that, after sulfide exposure under unaerated conditions, subsequent aerobic oxidative activity rates rapidly decreased as the soluble sulfide exposure was increased from 0.5 gm l(-1) S to 5 mg l(-1) S and that further reductions in this activity progressively developed as the concentration was increased to 200 mg l(-1) S. The recovery following unaerated exposure to sulfide was significantly higher at pH 7, as compared with pH 8, and although the specific nature of this variation was not established, a hypothetical explanation appeared warranted.