Post-processing Unit Research Articles

In-cycle combustion feedback control for abnormal combustion based on digital ion current signal

For better stability of ion current employed for in-cycle combustion diagnosis and feedback control, this research develops a digital post-processing unit for in-cylinder ion current signals. Based on the processed digital ion current signal, abnormal combustion in gasoline direct injection engine is successfully detected, and the in-cycle remedy feedback control is achieved as well. Both re-ignition and re-injection are utilized for misfiring remedy, and only re-injection is employed for knocking inhibition. The accuracy of misfiring diagnosis is achieved no less than 94%, and the re-injection combined with re-ignition operation is shown to be feasible for misfiring remedy as well. The accuracy of knocking diagnosis is around 85% (knocking rate = 20%). The re-injection under the pre-knocking condition is shown to be effective for knocking inhibition.

Process intensification with inline pre and post processing mechanism for valorization of poultry litter through high rate biomethanation technology: A full scale experience

High rate biomethanation technology based on anaerobic gas lift reactor (AGR) for the treatment of poultry litter (PL) has been demonstrated to generate biogas and digestate. The plant was installed and operated continuously for 95 weeks (September 2012 to June 2014) under ambient temperature conditions (in the range of 24–31 °C) for the treatment of 1000 kg of PL per day containing 254 kg of total solids and 220 kg of volatile solids. Biogas (68 m3/day) produced in the plant was successfully converted to electrical power (89 kWh/day) that was utilized to operate water pumps in the agricultural fields. The digestate (105 kg/day) was effectively employed in the nearby fields as an organic fertilizer. The plant was operated by establishing an intensified process mechanism incorporating inline pre and post processing unit assembly along with ammonia inhibition control mechanism. It is understood from the full scale experience of this plant that, decentralized off grid power generation from PL could be a remunerative option to poultry farmers.

A New Imaging System for Real-Time Process Control

In this paper, a new tomography technique called electrical charge tomography for two-phase flow imaging is presented. The probe consists of few pair of electrodes which are electrically energized to generate electrical charges within the fluid under test. The intensity of these charges depends on the chemical and physical properties of the fluid, as well as to its molecular distribution. Another group of electrodes surrounding the cross section of the fluid under test are used to capture the induced electrical charges. These are then converted into an electrical signal using a high sensitive charge amplifier. A postprocessing unit which consists of an analog to digital converter, followed by an field programmable gate array (FPGA) module is then used for high level signal processing (i.e., a dedicated dynamic thresholding algorithm) and image reconstruction. Experimental results demonstrate the capability of the system to accurately generate 2-D cross-sectional images, where the error is lower by up to 14% when using another electrical capacitance (ECT) tomography probe. The other advantage of this technique over ECT is the reduced data acquisition time, since in ECT a minimum time is required for the charge and discharge of the capacitance in order to achieve acceptable accuracy. This makes the probe another attractive concept for future tomography systems targeting real-time applications.

A New Readout System for LC Resonant Sensors

A new readout system based on LC resonant sensor is presented. The readout system consists of a reader coil inductively coupled to the LC resonant sensor, a measurement unit, and a PC post processing unit. The measurement unit generates an output voltage representing the sensor resonance, converts the output voltage to numerical form, and saves the converted digital data. The PC post processing unit processes the digital data and calculates the sensor's resonance frequency. The readout system enables wireless interrogation and its accuracy is exemplified by an experimental system. The experimental system can detect the resonant frequency of sensor automatically and effectively. The experimental results are presented for different sensor resonance frequencies with various sensor capacitance values and show good agreement with the theoretical results. The entire design is simple, easy to use, and widely applicable for applications where the coupling distance between sensor and reader coil is variable.

A novel readout system for wireless passive pressure sensors

This paper presents a novel readout system for wireless passive pressure sensors based on the inductively coupled inductor and cavity (LC) resonant circuits. The proposed system consists of a reader antenna inductively coupled to the sensor circuit, a readout circuit, and a personal computer (PC) post processing unit. The readout circuit generates a voltage signal representing the sensor’s capacitance. The frequency of the reader antenna driving signal is a constant, which is equal to the sensor’s resonant frequency at zero pressure. Based on mechanical and electrical modeling, the pressure sensor design based on the high temperature co-fired ceramic (HTCC) technology is conducted and discussed. The functionality and accuracy of the readout system are tested with a voltage-capacitance measurement system and demonstrated in a realistic pressure measurement environment, so that the overall performance and the feasibility of the readout system are proved.

A readout system for passive pressure sensors

This paper presents a readout system for the passive pressure sensors which consist of a pressure-sensitive capacitor and an inductance coil to form an LC circuit. The LC circuit transforms the pressure variation into the LC resonant frequency shift. The proposed system is composed of a reader antenna inductively coupled to the sensor inductor, a measurement circuit, and a PC post-processing unit. The measurement circuit generates a DC output voltage related to the sensor's resonant frequency and converts the output voltage into digital form. The PC post-processing unit processes the digital data and calculates the sensor's resonant frequency. To test the performance of the readout system, a sensor is designed and fabricated based on low temperature co-fired ceramic (LTCC), and a series of testing experiments is carried out. The experimental results show good agreement with the impedance analyzer's results, their error is less than 2.5%, and the measured values are almost insensitive to the variation of readout distance. It proves that the proposed system is effective practically.

LARGE-SCALE IMAGE PROCESSING WITH THE ROTSE PIPELINE FOR FOLLOW-UP OF GRAVITATIONAL WAVE EVENTS

Electromagnetic (EM) observations of gravitational-wave (GW) sources would bring unique insights into a source which are not available from either channel alone. However EM follow-up of GW events presents new challenges. GW events will have large sky error regions, on the order of 10-100 square degrees, which can be made up of many disjoint patches. When searching such large areas there is potential contamination by EM transients unrelated to the GW event. Furthermore, the characteristics of possible EM counterparts to GW events are also uncertain. It is therefore desirable to be able to assess the statistical significance of a candidate EM counterpart, which can only be done by performing background studies of large data sets. Current image processing pipelines such as that used by ROTSE are not usually optimised for large-scale processing. We have automated the ROTSE image analysis, and supplemented it with a post-processing unit for candidate validation and classification. We also propose a simple ad hoc statistic for ranking candidates as more likely to be associated with the GW trigger. We demonstrate the performance of the automated pipeline and ranking statistic using archival ROTSE data. EM candidates from a randomly selected set of images are compared to a background estimated from the analysis of 102 additional sets of archival images. The pipeline's detection efficiency is computed empirically by re-analysis of the images after adding simulated optical transients that follow typical light curves for gamma-ray burst afterglows and kilonovae. We show that the automated pipeline rejects most background events and is sensitive to simulated transients to limiting magnitudes consistent with the limiting magnitude of the images.

Speech Technologies for Advanced Applications in Service Robotics

The multimodal interface for controlling functions of the complex modular robotic system, which can be deployed in difficult conditions as are rescue works, natural disasters, fires, decontamination purposes was designed. Such interface involves several fundamental technologies such as speech recognition, speech synthesis and dialogue management. To enable human operator to cooperate with designed robotic system, the sophisticated architecture was designed and described technologies were implemented. The automatic speech recognition system is introduced, which is based on Hidden Markov models and enables to control functions of the system using a set of voice commands. The text-to-speech system was prepared for producing feedback to the operator and dialogue manager technology was adopted, which makes it possible to perform the information exchange between operator and robotic system. The system proposed is enriched with acoustic event detection system, which consists of a set of five microphones integrated on the robotic vehicle, the post-processing unit and detection unit.

Robust road-to-car communications by means of an active Ku-band RF Self-IDentification (RFSID) system

This paper deals with a robust RFSID (Radio Frequency Self IDentification) system for road-to-car communications. The RFSID-based system operates in Ku-band and consists of a fixed transmitter, located at the road side, and of a receiver unit placed on the moving target, i.e. a car in its first proposed application. A slotted waveguide antenna array is used to illuminate the moving object at the desired position, whereas a four-patch array antenna is adopted at the receiver side. Both the antennas have been designed using numerical simulations based on a Finite Difference Time Domain (FDTD) algorithm. When the moving object crosses the antenna beam a triggering pulse is generated by the receiver; such a pulse can be used to reset or update the electronics aboard the vehicle and to log specific information coming from location-based systems (LBSs), into the car equipments. A digital transmission of gold sequences and a post-processing unit have been exploited so far to increase the robustness and the accuracy of the system. At this stage of the development the system benefit of extensive field tests, being adopted for some years by many top Formula 1 racing teams as a lap trigger system, used to reset the on-board electronics when the car crosses either the finishing line and peculiar path reference points. The temporal accuracy exhibited is better than 1 ms with a coverage of about 90 m.

Design of Multicarrier OFDM Modulator/Demodulator Based on Discrete Hartley Transform

In this paper, a novel orthogonal frequency-division multiplexing (OFDM) modulator/demodulator based on real-valued discrete Hartley transform (DHT) is presented and implemented for the IEEE 802.11a/g wireless local area network (LAN). Instead of the conventional complex-valued fast Fourier transform (FFT) for OFDM systems, the proposed architecture employs two real-valued fast DHT (FHT) kernels and one post processing unit. By taking advantage of the real-valued operation of FHT, this approach reduces the number of multiplications compared with the radix-2 FFT. The proposed DHT-based modulator/demodulator was designed and fabricated in 0.18-µm CMOS technology with a core area of 928 × 935µm2. The average power consumption is about 20.16mW at 20MHz and 1.8V supply voltage. Measurement results of the integrated circuit illustrate its superior chip area and power consumption.

Ultrasound detection of gastric antrum motility--evaluating a simple semiquantitative method

This study was carried out to evaluate a simplified sonographic technique for the sonographic analysis of antral motility. For this purpose the percentage of visually complete contractions (estimated reduction of the antral area > 50%)/2 minutes was compared to the mean amplitude (%) and the mean velocity (%/s) of the contractions. The percentage of complete contractions was closely correlated to both the mean amplitude (r = 0.97, p < 0.0001) and the velocity (r = 0.92, p < 0.0001) of the antral contractions. Since the simplified technique is regardless to a postprocessing unit, which is not available in many sonolayers, it could be recommended as a valid routine screening method for the detection of antral motility disorders.

Drug/nondrug classification with consensual Self-Organising Map and Self-Organising Global Ranking algorithms

In this paper, a special consensual approach is discussed for separating the druglike compounds from the non-druglike compounds. It involves a group decision to produce a consensus of multiple classification results obtained with a single classification algorithm. The individual results are obtained with either the Self Organising Global Ranking (SOGR) or Self Organising Map (SOM). The main difference between the proposed algorithm and SOM is the neighbourhood concept. The constructed consensual model has a preprocessing unit which consists of transformation of input patterns by random matrices and median filtering to generate independent errors for a single type of classifier, and a postprocessing unit for consensus. The confirmed drugs were classified with a consensual accuracy of 90.63% while nondrugs resulted in 80.44% accuracy. The SOGR results were better than the SOM algorithm results.

Inference on white dwarf binary systems using the first round Mock LISA Data Challenges data sets

We report on the analysis of selected single source data sets from the first round of the mock LISA data challenges (MLDC) for white dwarf binaries. We implemented an end-to-end pipeline consisting of a grid-based coherent pre-processing unit for signal detection and an automatic Markov Chain Monte Carlo (MCMC) post-processing unit for signal evaluation. We demonstrate that signal detection with our coherent approach is secure and accurate, and is increased in accuracy and supplemented with additional information on the signal parameters by our Markov Chain Monte Carlo approach. We also demonstrate that the Markov Chain Monte Carlo routine is additionally able to determine accurately the noise level in the frequency window of interest.

Application of expert networks for predicting proteins secondary structure

The present study utilizes expert neural networks for the prediction of proteins secondary structure. We use three independent networks, one for each structure (alpha, beta and coil) as the first-level processing unit; decision upon the chosen structure for each residue is carried out by a second-level, post-processing unit, which utilizes the Chou and Fasman frequency values F α and F β in order to strengthen and/or deplete the probability of the specific structure under investigation. The highest prediction case was 76%. Our method requires primitive computational means and a relatively small training set, while still been comparable to previous work. It is not meant to be an alternative to the determination of secondary structure by means of free energy minimization, integration of dynamic equations of motion or crystallography, which are expensive, time-consuming and complicated, but to provide additional constrains, which might be considered and incorporated into larger computing setups in order to reduce the initial search space for the above methods.

A Hardware/Software Co-Design of MP3 Audio Decoder

The Moving Picture Experts Group (MPEG) audio coding standard offers three levels of compression algorithms where the MPEG Layer III (MP3) has the best quality but with the most complexity. There are several complex coding techniques involved in MP3 audio decoding algorithm, therefore, it is difficult to make an efficient architecture design. This paper presents a hardware/software co-design method for the implementation of MP3 audio decoder, which meets the real-time requirement of MP3 standard. The software and hardware part of this decoder is partitioned into a pre-processing and a post-processing unit respectively. The pre-processing unit with a programmable parser processor is developed for the implementation of intensive decision making operations needed for audio bitstreams. The post-processing unit with a dedicated hardware of modified fast algorithm is designed for the regular and computation-intensive operations in MP3 audio decoding flow. The architecture achieves a high throughput with a reduced memory requirement and hardware complexity. With a two-level pipeline approach, it allows a high hardware utilization and is suitable to low power implementation. The proposed decoder system has been designed and implemented using VLSI cell-based approach. The die size is 3.5 × 4.45 mm2 with the maximum operation frequency of 20 MHz.

Computerized Data Reduction and Analysis in Positron Annihilation Coincidence Doppler Broadening Spectroscopy

Positron annihilation spectroscopy is a sensitive probe for studying the electronic structure of defects in solids. The high-momentum part of the Doppler-broadened spectra can be used to distinguish different elements at the annihilation site. This can be achieved by using a two-detector coincidence system, which reduces the peak to background ratio dramatically. The coincident events have to be extracted from a two-dimensional spectrum that is recorded by two high-purity germanium detectors. For this purpose the computer program MePASto was developed, which allows an automated data reduction from such Doppler-coincidence spectra, supplemented by a post-processing unit for data analysis. Additionally a case study of the identification of defect sites in an intermetallic compound is presented.

An FIR processor with programmable dynamic data ranges

This work developed a modified direct form based on the radix-4 Booth algorithm to realize a finite impulse response (FIR) architecture with programmable dynamic ranges of input data and filter coefficients. This architecture comprises a preprocessing unit, data latches, configurable connection units, double Booth decoders, coefficient registers, a path control unit, and a postprocessing unit. Programmable dynamic ranges of input data and filter coefficients can be any positive even numbers or multiple of a word length of coefficient registers, using configurable connection units or a path control unit, respectively. In particular, the proposed architecture employs only data-path controls to accomplish programmable operations, without changing word lengths and components of data latches and filter taps. A practical 8-bit and 16-bit FIR processor has also been implemented by using the TSMC 5 V 0.6 /spl mu/m CMOS technology. It is suitable for operations of asymmetric, symmetric, and anti-symmetric filters at 64, 63, 32, 31, and 16 taps, and is well explored to optimize its functional units. The proposed processor has throughput rates of 50 M and 25 M samples/s for 8-bit and 16-bit input data of various filter applications, respectively.

Digital Film Mastering

A new approach for generating video masters from film originals is presented in this paper. The basis is a high-throughput film scanner with a data output option that enables the generation of a high-resolution digital data copy. By combining standard computer platforms and dedicated processing hardware, an integrated system is created where multiple master video copies of differing formats can be derived from a single digital data copy. This flexible and efficient method of generating different versions of a program facilitates multimedia distribution of an original film. The paper also presents the overall concept and architecture for digital film mastering and explains, in particular, the architecture of a crucial component: the post-processing unit. The specific challenges that arise from the processing of continuous data streams at rates up to 420 Mbytes/sec are discussed. An example based on an actual film scanner from Philips Digital Video Systems is used to illustrate the method.

On the coordination of product and by-product flows in two-level distribution networks: Model formulations and solution procedures

We study the problem of coordinating product and by-product flows in a two-level distribution network. In this problem, a single product is produced at multiple plants in order to fulfill customer demands. Furthermore, in the production process a by-product is produced, that must be transported to, and processed at a post-processing unit. The problem objective is to determine suitable locations for plants and post-processing units from a predetermined set of feasible locations, such that total costs are minimal. Here, total costs consist of fixed costs associated with opening plants and post-processing units, and variable costs associated with transport of product and by-product. We discuss alternative mathematical model formulations for this problem, and derive lower and upper bounding procedures. The results from computational experiments — in which we analyse the numerical behaviour of these procedures — are also reported.

The PLAST3 system and its application to the simulation of an open die forging operation

Modelling large three-dimensional metal forming deformations with the finite-element program PLAST3 is presented. The program utilises the penalty constrained method, based on the rigid-plastic flow formulation. The structure and main capabilities of this program are described. The post-processing unit PLAPOST3 utilized for the analysis of the simulation results in a graphical form is presented also, this unit being written in LISP language inside a commercial CAD package. A sample solution supported by experimental work carried out with an aluminium alloy at room temperature is included. Theoretical and experimental results are analysed, good agreement between them being found.