Extra Path Research Articles

A Study of the Virtual Microphone Algorithm for ANC System Working in Audio Interference Environment

Two kinds of anti-audio interference active noise control (ANC) algorithms are proposed based on a conventional filtered-X least mean squares virtual microphone (FXLMS-VM) algorithm. The proposed filtered-X least mean squares virtual microphone and anti-audio interference (FXLMS-VM-AI) algorithm employs an extra audio path to compensate for the influence of the audio interference phenomenon on the ANC adaptive filter. The proposed time frequency mixed filtered-X least mean squares virtual microphone and anti-audio interference (TFM-FXLMS-VM-AI) algorithm can overcomes this audio interference effect by calculating the coefficients of the ANC adaptive filter in the frequency domain. The time domain acoustic wave field simulation method is adopted to test the performance of the proposed ANC algorithms in an audio interference environment. By analyzing the simulation results, both proposed algorithms show better convergence accuracy in terms of the adaptive filter coefficients and better audio signal performance than the conventional algorithm. The proposed FXLMS-VM-AI algorithm has a faster convergence speed for the ANC adaptive filter than the proposed TFM-FXLMS-VM-AI algorithm. The proposed TFM-FXLMS-VM-AI algorithm has a lower computational complexity than the conventional algorithm and the proposed TFM-FXLMS-VM-AI algorithm.

THE IMPACT OF THE NUMBER OF TEARS IN PATIENT-SPECIFIC STANFORD TYPE B AORTIC DISSECTING ANEURYSM: CFD SIMULATION

It is believed that the progression of Stanford type B aortic dissection is closely associated with vascular geometry and hemodynamic parameters. The hemodynamic differences owing to the presence of greater than two tears have not been explored. The focus of the present study is to investigate the impact of an additional re-entry tear on the flow, pressure and wall shear stress distribution in the dissected aorta. A 3D aorta model with one entry and one re-entry tear was generated from computed tomography (CT) angiographic images of a patient with Stanford Type B aortic dissection. To investigate the hemodynamic effect of more than two tear locations, an additional circular re-entry tear was added 24 mm above the original re-entry tear. Our simulation results showed that the presence of an additional re-entry tear provided an extra return path for blood back to the true lumen during systole, and an extra outflow path into the false lumen during diastole. The presence of this additional path led to a decrease in the false lumen pressure, particularly at the distal region. Meanwhile, the presence of this additional tear causes no significant difference on the time average wall shear stress (TAWSS) distribution except at regions adjacent to re-entry tear 2. Moderate and concentrated TAWSS was observed at the bottom region of this additional tear which may lead to further extension of the tear distally.

Edge effect of optical surfacing process with different data extension algorithms

This study presents a strategy which integrates extra polishing path (EPP) and error map extension to weaken the edge effect in the ultraprecise optical surfacing process. Different data extension algorithms were presented and analyzed. The neighbor-hood average can be selected as the frequently-used method, as it has not bad precision and time-saving performance for most surface forms through the simulation results and practical experiment. The final error map was obtained, its peak-to-valley (PV) was 0.273λ and root mean square (RMS) was 0.028λ (λ = 632.8 nm). The edge effect was weakened and suppressed well through the experiment.

Modulation of peak-to-valley current ratio of Coulomb blockade oscillations in Si single hole transistors

We demonstrate a method to modulate the peak-to-valley current ratio of Coulomb blockade oscillation peaks in room temperature-operating Si single-hole tunnel transistors. By connecting the extra p+in+ junction (i.e., a current effluence path) to the drain reservoir, we effectively deplete the leakage current (i.e., valley current) that stem from the diffusion current of the parasitic field-effect transistor within the device. The addition of the extra current-effluence path significantly improves the Coulomb blockade characteristics in comparison to the original Coulomb blockade oscillations. We believe the method is advantageous for designing high performance Si single electron/hole tunnel devices.

Global uncut regions removal for efficient contour-parallel milling

To improve the efficiency of contour-parallel offset (CPO) roughing process, the tool path interval is usually set greater than the cutter radius. However, this will cause uncut regions in some corner area. Existing methods both in the literatures and commercial software remove the uncut regions by appending extra clear-up tool path to the local corners. In this paper, we offer an alternative solution to the uncut region problem from a global point of view. The basic idea of our solution is first to link all the uncut regions into a clear-up tool path and then drive the cutter along this path to remove the uncut regions. This clear-up tool path is formed in three steps. Firstly, the uncut regions are detected and expressed by uncutlines. Secondly, the uncutlines are jointed into several arcs based on the level, angle, and distance conditions. Finally, these arcs are further linked into a single curve according to CPO centers. This single curve can be used as the clear-up tool path if proper feed speed is set. Cutting experiments show that the proposed clear-up tool path works well in the real cutting environment and can improve the machining efficiency of the roughing process.

Wideband Q-VCO using tail-current shaping based automatic amplitude control

A wideband Q-VCO circuit with two tail-current branches ranging from 1.54GHz to 2.8GHz is proposed by tail-current shaping based automatic amplitude control (AAC). In Q-VCO's outputs, the AC component combing with the negative peak are injected back to the tail-current transistors as biasing voltage so as to reduce the tail-current noise contribution and realize the AAC. Moreover, an extra current path is enabled at higher frequency in order to suppress the tail-current increment for further LC-tank amplitude reduction, which is connected between the two tail-current branches. The proposed circuit was analyzed by SpectreRF simulator using TSMC 0.18μm CMOS technology with a power supply of 1.8V. The phase noise at 1MHz frequency offset is from −132.6dBc/Hz at 1.54GHz to −125.3dBc/Hz at 2.8GHz while the FOM is about −182dBc/Hz. Besides, within the tuning frequency, the maximum LC-tank amplitude variation is only 326mV, which is 2.25 times less than that of the Q-VCO without the AAC.

Evaluations of current control in weak grid case for grid‐connected LCL‐filtered inverter

For grid-connected inverters, switching harmonics can be effectively attenuated through an LCL-type filter. In order to suppress resonance and guarantee good performance, many strategies (e.g. active damping (AD), harmonic resonant control, repetitive control and grid feedforward) have been proposed. However, the wide variation of grid impedance value challenges system stability in practical applications. The aforementioned methods need to be investigated. This study evaluates the applicability of each part of the overall control in a weak grid case with the use of a stability criterion. It has been demonstrated that the feedback-based AD control can work well in a wide range of grid conditions. However, the resonant and repetitive control methods meet constraints. The grid feedforward method brings in an extra positive feedback path, and consequently results in high harmonics or even instability. Finally, a recommendation for system design has been presented. Simulations and experiments have been provided to verify the analysis.

Primo Vascular System Accompanying a Blood Vessel from Tumor Tissue and a Method to Distinguish It from the Blood or the Lymph System

A primo vessel was observed in the abdominal cavity in the lung cancer mouse model, and its function as an extra metastatic path was observed. In this work, we found a primo vessel accompanying a blood vessel emanating from a tumor in the skin. We also presented simple and efficient criteria to distinguish a primo vessel from a blood or a lymph vessel and from a nerve. The criteria for using DAPI and Phalloidin will be useful in clinical situations to find and identify the primo vessels among the blood vessels, lymph vessels, or nerves in the tissue surrounding a tumor such as a melanoma or breast cancer.

Dehydroxyl effect of Sn-doped silicon oxide resistance random access memory with supercritical CO2 fluid treatment

The tin-doped can supply conduction path to induce resistance switching behavior. However, the defect of tin-doped silicon oxide (Sn:SiOx) increased the extra leakage path lead to power consumption and joule heating degradation. In the study, supercritical CO2 fluids treatment was used to improve resistive switching property. The current conduction of high resistant state in post-treated Sn:SiOx film was transferred to Schottky emission from Frenkel-Poole due to the passivation effect. The molecular reaction model is proposed that the defect was passivated through dehydroxyl effect of supercritical fluid technology, verified by material analyses of x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy.

방전드릴링에서 홀 관통 평가 방법

The Electric discharge machining (EDM) process is used to minimize the difference between designed feature and machined feature while the most workpiece is removed through the cutting processes. The tiny-deep hole machining and perpendicular wall machining in mold and die are good applications of EDM. Among EDM equipment, the super drill uses the hollowed electrode to eliminate the debris which causes the second discharge with the electrode and degrades the machining quality. Through the hollow, the high pressured discharge oil is supplied to remove the debris together with the spindle rotation. The thin-hollow electrode tends to easily wear out compared to the sold die-sinking electrode and its wear rate is might not allowed to monitor in real time during discharging. Up to now, the wear amount is measured by off line method, which leads machining time to increase because the hole pass-through moment can be check by visual (manually) with the extra tool path. Therefore, this study suggests the attractive method to evaluate the hole pass-through moment in which the gap voltage and z-axis encoder pulse are monitored to predict the moment. The commercial super drill is used to validate the proposed method and the experiment is carried out.

A low on-resistance SOI LDMOS using a trench gate and a recessed drain

An integrable silicon-on-insulator (SOI) power lateral MOSFET with a trench gate and a recessed drain (TGRD MOSFET) is proposed to reduce the on-resistance. Both of the trench gate extended to the buried oxide (BOX) and the recessed drain reduce the specific on-resistance (Ron,sp) by widening the vertical conduction area and shortening the extra current path. The trench gate is extended as a field plate improves the electric field distribution. Breakdown voltage (BV) of 97 V and Ron,sp of 0.985 mΩ·cm2 (VGS = 5 V) are obtained for a TGRD MOSFET with 6.5 μm half-cell pitch. Compared with the trench gate SOI MOSFET (TG MOSFET) and the conventional MOSFET, Ron,sp of the TGRD MOSFET decreases by 46% and 83% at the same BV, respectively. Compared with the SOI MOSFET with a trench gate and a trench drain (TGTD MOSFET), BV of the TGRD MOSFET increases by 37% at the same Ron,sp.

SENSITIVITY OF CELLULAR WIRELESS NETWORK PERFORMANCE TO SYSTEM & PROPAGATION PARAMETERS AT CARRIER FREQUENCIES GREATER THAN 2 GHz

In this paper, mathematical analysis supported by computer simulation is used to investigate the impact of both system and propagation loss parameters on the performance of cellular wireless network operating at microwave carrier frequencies greater than 2 GHz, where multiple tier of co-channel interfering cells are considered to be active. The two-slope path loss model and the uplink information capacity of the cellular network is used for the performance analysis. Results show that for carrier frequencies greater than 2 GHz and smaller cell radius multiple tier of co-channel interfering cells become active as compared to carrier frequencies lesser than 2 GHz. The multiple tier of co-channel interfering cells, leads to a decrease in the information capacity of the cellular wireless network. The results also show that the system performance is sensitive to most of the propagation model parameters such as the basic and extra path loss exponent.

Weighted Transition Based Reordering, Columnwise Bit Filling, and Difference Vector: A Power-Aware Test Data Compression Method

Test data compression is the major issues for the external testing of IP core-based SoC. From a large pool of diverse available techniques for compression, run length-based schemes are most appropriate for IP cores. To improve the compression and to reduce the test power, the test data processing schemes like “don't care bit filling” and “reordering” which do not require any modification in internal structure and do not demand use of any test development tool can be used for SoC-containing IP cores with hidden structure. The proposed “Weighted Transition Based Reordering-Columnwise Bit Filling-Difference Vector (WTR-CBF-DV)” is a modification to earlier proposed “Hamming Distance based Reordering—Columnwise Bit Filling and Difference vector.” This new method aims not only at very high compression but also aims at shift in test power reduction without any significant on-chip area overhead. The experiment results on ISCAS89 benchmark circuits show that the test data compression ratio has significantly improved for each case. It is also noteworthy that, in most of the case, this scheme does not involve any extra silicon area overhead compared to the base code with which it used. For few cases, it requires an extra XOR gate and feedback path only. As application of this scheme increases run length of zeroes in test set, as a result, the number of transitions during scan shifting is reduced. This may lower scan power. The proposed scheme can be easily integrated into the existing industrial flow.

Photonic bandgap under irradiation of a Gaussian beam

The transfer matrix of a dielectric slab under propagation of a Gaussian beam was formulated. The derived matrix was applied for a one-dimensional photonic crystal (1DPC) structure and the transmittance spectrum and photonic bandgap (PBG) properties were investigated. An r-dependent (r is the radial coordinate of the Gaussian beam) PBG was obtained. With the increase of r, a redshift and a decrease in the PBG are observed. Higher PBGs experience more shift. Also properties of the photonic crystal (PC) structure with defect layer were investigated and displacement to red and decrease of the defect mode peak height, with an increase of r, were observed. The extra optical path that the outer rays travel due to the oblique propagation compared to the central ray in a Gaussian beam is responsible for these effects. For long Rayleigh ranges our results for the Gaussian beam were the same as that for plane wave.

Inter-channel offset and gain mismatch correction for time-interleaved pipelined ADCs

This paper presents a digital background calibration technique to compensate inter-channel gain and offset errors in parallel, pipelined analog-to-digital converters (ADCs). By using an extra analog path, calibration of each ADC channel is done without imposing any changes on the digitizing structure, i.e., keeping each channel completely intact. The extra analog path is simplified using averaging and chopping concepts, and it is realized in a standard 0.18‐μm CMOS technology. The complexity of the analog part of the proposed calibration system is same for a different number of channels.Simulation results of a behavioral 12-bit, dual channel, pipelined ADC show that offset and gain error tones are improved from −56.5 and −58.3dB before calibration to about −86.7 and −103dB after calibration, respectively.

Weak bisimulation is sound and complete for [formula omitted

We investigate weak bisimulation of probabilistic systems in the presence of nondeterminism, i.e. labelled concurrent Markov chains (LCMC) with silent transitions. We develop an approach based on allowing convex combinations of computations, similar to Segala and Lynch’s use of randomized schedulers. The definition of weak bisimulation destroys the additivity property of the probability distributions, yielding instead capacities. The mathematics behind capacities naturally captures the intuition that when we deal with nondeterminism we must work with bounds on the possible probabilities rather than with their exact values. Our analysis leads to three new developments: • We identify a characterization of “image finiteness” for countable-state systems and present a new definition of weak bisimulation for these LCMCs. We prove that our definition coincides with that of Philippou, Lee and Sokolsky for finite state systems. • We show that bisimilar states have matching computations. The notion of matching involves convex combinations of transitions. • We study a minor variant of the probabilistic logic pCTL ∗ – the variation arises from an extra path formula to address action labels. We show that bisimulation is sound and complete for this variant of pCTL ∗ . This is an extended complete version of a paper that was presented at CONCUR 2002.

The effect of coating crystallization and substrate impurities on magnetron sputtered doped LaCrO 3 coatings for metallic solid oxide fuel cell interconnects

For IT-SOFC metallic interconnects, surface coating is effective for reducing Cr poisoning of the cathode and controlling scale growth. In this work, LaCrO 3 and doped LaCrO 3 coatings were deposited by magnetron sputtering on SS446 and Crofer 22 APU substrates. The crystallization process was studied by means of X-ray Diffraction (XRD) during the annealing of the sputter coated samples in ambient and reducing environments. The formation of intermediate phases when annealed in air, LaCrO 4 and La 2CrO 6, results in vacancy formation upon subsequent transformation to the LaCrO 3 phase and thus a decreased oxidation resistance. While the avoidance of an intermediate phase change when the coatings are initially annealed in a reducing environment leads to dense and compact coatings. This confirmed both by XRD and by scanning electron microscopy (SEM) of coating cross-sections. Crofer 22 APU alloys with various silicon and aluminum levels are deposited with doped LaCrO 3 coating to study substrate impurity effects on coating properties. It was found that silicon content in the substrates leads to increased ASR of the coatings. In addition, long term annealing in air shows that aluminum impurities in the substrate can lead to the formation of alumina at substrate grain boundaries, which in turn leads to enhanced Mn migration at the grain boundaries. Increased manganese concentrations at the film/grain boundary interface in coated samples produces larger than normal amounts of (Mn,Cr) 3O 4 spinel in these regions, which cracks the coating and reduces the ASR value due to extra electronic conduction path. A similar mechanism is not observed in a low Al/Si alloy.

Electromigration-Induced Plasticity: Texture Correlation and Implications for Reliability Assessment

Plastic behavior has previously been observed in metallic interconnects undergoing high current density electromigration (EM) loading. In this study of Cu interconnects, using the synchrotron technique of white beam X-ray microdiffraction, we have further found preliminary evidence of a texture correlation. In lines with strong (111) textures, the extent of plastic deformation is found to be relatively large compared to that of weaker textures. We suggest that this strong (111) texture may lead to an extra path of mass transport in addition to the dominant interface diffusion in Cu EM. When this extra mass transport begins to affect the overall transport process, then the effective diffusivity, D{sub eff}, of the EM process is expected to deviate from that of interface diffusion only. This would have fundamental implications. We have some preliminary observations that this might be the case, and we report its implications for EM lifetime assessment in this manuscript.

Growth of Carbon Nanotubes on Fully Processed Silicon-On-Insulator CMOS Substrates

This paper describes the growth of Carbon Nanotubes (CNTs) both aligned and non-aligned on fully processed CMOS substrates containing high temperature tungsten metallization. While the growth method has been demonstrated in fabricating CNT gas sensitive layers for high temperatures SOI CMOS sensors, it can be employed in a variety of applications which require the use of CNTs or other nanomaterials with CMOS electronics. In our experiments we have grown CNTs both on SOI CMOS substrates and SOI CMOS microhotplates (suspended on membranes formed by post-CMOS deep RIE etching). The fully processed SOI substrates contain CMOS devices and circuits and additionally, some wafers contained high current LDMOSFETs and bipolar structures such as Lateral Insulated Gate Bipolar Transistors. All these devices were used as test structures to investigate the effect of additional post-CMOS processing such as CNT growth, membrane formation, high temperature annealing, etc. Electrical characterisation of the devices with CNTs were performed along with SEM and Raman spectroscopy. The CNTs were grown both at low and high temperatures, the former being compatible with Aluminium metallization while the latter being possible through the use of the high temperature CMOS metallization (Tungsten). In both cases we have found that there is no change in the electrical behaviour of the CMOS devices, circuits or the high current devices. A slight degradation of the thermal performance of the CMOS microhotplates was observed due to the extra heat dissipation path created by the CNT layers, but this is expected as CNTs exhibit a high thermal conductance. In addition we also observed that in the case of high temperature CNT growth a slight degradation in the manufacturing yield was observed. This is especially the case where large area membranes with a diameter in excess of 500 microns are used.

GPS Reflected Signal Analysis using Software Receiver

A reflected GPS signal is normally considered as noise (multipath). However, we believe that a reflected signal contains information about the reflecting object. Though, this information may not be useful for accurate position computation, it may help us to identify the reflecting object itself, which is a type of remote sensing. Besides, by measuring the time delay of the reflected signal, it is possible to estimate the extra path length the reflected signal has to travel. Hence, in general, the analysis of reflected signal can be used for two broad categories of altimetry and remote sensing. However, this type of analysis is rather limited with current commercial GPS receivers. We are in the process of developing a software-based GPS receiver that is capable of reflected signal analysis for remote sensing purpose. The receiver consists of multi-polarization (RHCP and LHCP) array of GPS antennas, front-end device, a PC and necessary software for signal processing. In this paper, we discuss about the system architecture and algorithms, results of reflected signal analysis observed at different places in different conditions and antenna types. Finally, we will discuss the possibility of the system for remote sensing applications using GPS signal.