Pub Date : 2003-06-09DOI: 10.1109/ISIE.2003.1267904
S. Fujisawa, K. Akazawa, R. Kurozumi, K. Kawada, T. Yamamoto, H. Uenaka
We developed a posture control system for an electric wheelchair equipped with active suspension, using CMAC, which is a neural network type of control. Testing of the posture control of the wheelchair, which considers a learning results as an output to the target value inputted on-line using the learning function of CMAC (cerebellar model arithmetic controller), was performed. In this paper, testing of the learning control, which holds the posture horizontally both by the simulation and in the experiment by the system, is performed, and the validity of CMAC is verified compared with conventional method.
{"title":"Posture control by on-line learning using CMAC for electric wheelchairs","authors":"S. Fujisawa, K. Akazawa, R. Kurozumi, K. Kawada, T. Yamamoto, H. Uenaka","doi":"10.1109/ISIE.2003.1267904","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267904","url":null,"abstract":"We developed a posture control system for an electric wheelchair equipped with active suspension, using CMAC, which is a neural network type of control. Testing of the posture control of the wheelchair, which considers a learning results as an output to the target value inputted on-line using the learning function of CMAC (cerebellar model arithmetic controller), was performed. In this paper, testing of the learning control, which holds the posture horizontally both by the simulation and in the experiment by the system, is performed, and the validity of CMAC is verified compared with conventional method.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131102640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-06-09DOI: 10.1109/ISIE.2003.1267950
R. Morais, A. Valente, J. Correia, C. Couto
This paper describes a CMOS mixed-signal interface with a RF transmitter. This die is assembled in a multi-chip-module (MCM) micro-system together with the micromachined soil moisture sensor to achieve a cost-effective solution with accurate and reliable measurements for soil moisture in agriculture. The soil moisture probe, based on dual-probe heat-pulse (DPHP) method, is fabricated in bulk-micromachining technology. The DPHP method is based on the measurement of the maximum temperature rise at some distance from the heater, after applying a heat-pulse. The measurement of the temperature rise is obtained by subtracting soil temperature from the probe temperature. The mixed-signal interface Ls based on a pre-amplification stage and first-order sigma-delta modulator. The bit-stream output of the modulator is then applied to a counter as a first order decimation filter thus providing a 12-bit readout sample. Prior to transmission, data is encoded as a pulse width modulated (PWM) signal and then transmitted by means of an amplitude shift-keying (ASK) modulation. The transmitter features a VCO phase locked to the quartz crystal reference of 13.56 MHz to achieve a carrier frequency of 433.92 MHz. A RF power amplifier based on class E topology was chosen. The CMOS mixed-signal interface with a RF transmitter has been implemented in a single-chip using a standard CMOS process (AMI 0.7 /spl mu/m, n-well, 2 metals and 1 poly).
{"title":"A CMOS mixed-signal interface with a RF transmitter for a micromachined soil moisture sensor","authors":"R. Morais, A. Valente, J. Correia, C. Couto","doi":"10.1109/ISIE.2003.1267950","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267950","url":null,"abstract":"This paper describes a CMOS mixed-signal interface with a RF transmitter. This die is assembled in a multi-chip-module (MCM) micro-system together with the micromachined soil moisture sensor to achieve a cost-effective solution with accurate and reliable measurements for soil moisture in agriculture. The soil moisture probe, based on dual-probe heat-pulse (DPHP) method, is fabricated in bulk-micromachining technology. The DPHP method is based on the measurement of the maximum temperature rise at some distance from the heater, after applying a heat-pulse. The measurement of the temperature rise is obtained by subtracting soil temperature from the probe temperature. The mixed-signal interface Ls based on a pre-amplification stage and first-order sigma-delta modulator. The bit-stream output of the modulator is then applied to a counter as a first order decimation filter thus providing a 12-bit readout sample. Prior to transmission, data is encoded as a pulse width modulated (PWM) signal and then transmitted by means of an amplitude shift-keying (ASK) modulation. The transmitter features a VCO phase locked to the quartz crystal reference of 13.56 MHz to achieve a carrier frequency of 433.92 MHz. A RF power amplifier based on class E topology was chosen. The CMOS mixed-signal interface with a RF transmitter has been implemented in a single-chip using a standard CMOS process (AMI 0.7 /spl mu/m, n-well, 2 metals and 1 poly).","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133422894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-06-09DOI: 10.1109/ISIE.2003.1267308
C. Stein, H.A. Grundlong, H. Pinheiro, J. R. Pinheiro, H. Hey
This paper presents a comparative analysis of a set of soft-transition techniques applied in inverters utilizing IGBT as power switches. The techniques are compared based in losses, number of components, stresses and type of commutation obtained. An estimation of power losses and junction temperature of insulated gate bipolar transistor (IGBT) devices is used to compare the soft-transition techniques. The method used to estimate the losses and temperatures is based in the data obtained from the devices data sheets and in the governing equation of the auxiliary circuits. This method uses a program written in MATLAB, which make use of an iterative process to obtain the convergence of the values of losses and temperature. Experimental results of the soft-transition techniques are presented, as well as a discussion about their characteristics.
{"title":"Analysis and comparison of soft-transition inverters","authors":"C. Stein, H.A. Grundlong, H. Pinheiro, J. R. Pinheiro, H. Hey","doi":"10.1109/ISIE.2003.1267308","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267308","url":null,"abstract":"This paper presents a comparative analysis of a set of soft-transition techniques applied in inverters utilizing IGBT as power switches. The techniques are compared based in losses, number of components, stresses and type of commutation obtained. An estimation of power losses and junction temperature of insulated gate bipolar transistor (IGBT) devices is used to compare the soft-transition techniques. The method used to estimate the losses and temperatures is based in the data obtained from the devices data sheets and in the governing equation of the auxiliary circuits. This method uses a program written in MATLAB, which make use of an iterative process to obtain the convergence of the values of losses and temperature. Experimental results of the soft-transition techniques are presented, as well as a discussion about their characteristics.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"16 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134428018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-06-09DOI: 10.1109/ISIE.2003.1267955
M. da S Vilela, J. Vilela, L. D. de Freitas, E. Coelho, J. Vieira, V.J. de Farias
This paper presents a new control technique with low harmonic distortion for the input power factor correction in a three-phase boost converter. This control technique is similar to the hysteresis control, but the switching frequency is kept practically constant. This technique can be employed since that the converter output voltage is three times greater than the maximum phase neutral input voltage. This paper proposes a wide study on the hysteresis control with practically constant frequency applied to the three-phase boost converter, where simulation results show the current behavior in each phase and the frequency variation along a switching cycle. It is also shown that the switching frequency variation is negligible.
{"title":"Proposal of a hysteresis control technique with almost constant frequency applied to the three phase boost converter","authors":"M. da S Vilela, J. Vilela, L. D. de Freitas, E. Coelho, J. Vieira, V.J. de Farias","doi":"10.1109/ISIE.2003.1267955","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267955","url":null,"abstract":"This paper presents a new control technique with low harmonic distortion for the input power factor correction in a three-phase boost converter. This control technique is similar to the hysteresis control, but the switching frequency is kept practically constant. This technique can be employed since that the converter output voltage is three times greater than the maximum phase neutral input voltage. This paper proposes a wide study on the hysteresis control with practically constant frequency applied to the three-phase boost converter, where simulation results show the current behavior in each phase and the frequency variation along a switching cycle. It is also shown that the switching frequency variation is negligible.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124226484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-06-09DOI: 10.1109/ISIE.2003.1267925
S. Rafael, A. Pires, P. J. Costa Branco
This paper describes the systematic procedure for designing a MOSFET power converter for an 8/6-switched reluctance machine. Starting from establishing its topology and subsystems, a Matlab simulation approach is initially developed to design its driving circuits, test different converter operating modes, and phase current controllers. Experimental tests are performed to verify the converter functionality and performance, comparing, correcting and discussing the results obtained with simulation analysis.
{"title":"Implementation of an 8/6 switched reluctance MOSFET current controller: simulation study and experimental tests","authors":"S. Rafael, A. Pires, P. J. Costa Branco","doi":"10.1109/ISIE.2003.1267925","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267925","url":null,"abstract":"This paper describes the systematic procedure for designing a MOSFET power converter for an 8/6-switched reluctance machine. Starting from establishing its topology and subsystems, a Matlab simulation approach is initially developed to design its driving circuits, test different converter operating modes, and phase current controllers. Experimental tests are performed to verify the converter functionality and performance, comparing, correcting and discussing the results obtained with simulation analysis.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132387850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-06-09DOI: 10.1109/ISIE.2003.1267266
S. D'arco, L. Piegari, R. Rizzo
The problem of the estimation of rotating speed is a very important problem, especially for systems that works with high dynamics. Actually the most common way to measure velocity is to use an incremental encoder. However the precision of the velocity estimation is yet a not completely solved problem. Typically, it is possible to increase the accuracy of the measure increasing the observation time, but during dynamic phenomena this could be dangerous for the efficiency and the stability of the control of the system. In the paper authors have proposed an innovative algorithm for the estimation of velocity starting from the output signal of an incremental encoder. The algorithm proposed can be used either at steady state or in dynamic conditions because it has a self-adjustable observation time in function of velocity and acceleration of the system. The algorithm has been tested in laboratory and experimental results have been reported in the paper.
{"title":"Experimental validation of a velocity estimation algorithm for speed control of electrical drives","authors":"S. D'arco, L. Piegari, R. Rizzo","doi":"10.1109/ISIE.2003.1267266","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267266","url":null,"abstract":"The problem of the estimation of rotating speed is a very important problem, especially for systems that works with high dynamics. Actually the most common way to measure velocity is to use an incremental encoder. However the precision of the velocity estimation is yet a not completely solved problem. Typically, it is possible to increase the accuracy of the measure increasing the observation time, but during dynamic phenomena this could be dangerous for the efficiency and the stability of the control of the system. In the paper authors have proposed an innovative algorithm for the estimation of velocity starting from the output signal of an incremental encoder. The algorithm proposed can be used either at steady state or in dynamic conditions because it has a self-adjustable observation time in function of velocity and acceleration of the system. The algorithm has been tested in laboratory and experimental results have been reported in the paper.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"11 7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129088200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-06-09DOI: 10.1109/ISIE.2003.1267984
G. L. Cascella, N. Salvatore, L. Salvatore
This paper proposes a new scheme to guarantee speed sensorless control and optimal field orientation of surface permanent magnet synchronous motors (SPMSMs) even if parameter deviations occur and initial rotor position is unknown. A novel adaptive sliding-mode observer is used for field oriented speed sensorless control. First the induced e.m.f. components are observed using the sliding-mode technique with an adaptive switching gain. Then a low-pass filter with an adaptive amplitude compensator, that works as derivative observer, is used to get rid of the chattering noise of estimated e.m.f. components and to calculate rotor speed and position. The current components in rotor reference frame are estimated from the active and reactive electromagnetic torques calculated in both the stationary reference frame and the estimated rotor one. The latter is also used as control reference frame. Inverter, filters and observer cause unavoidable and unpredictable time-delay in rotor position estimation, so that the control reference frame is delayed as to the actual rotor one. As a consequence, field orientation and maximum torque/current ratio do not occur when the desired field oriented current references are imposed in the control reference frame. An original field orientation PI controller is used to provide the appropriate current references in the control reference frame. Test results are presented to prove the approach effectiveness.
{"title":"Adaptive sliding-mode observer for field oriented sensorless control of SPMSM","authors":"G. L. Cascella, N. Salvatore, L. Salvatore","doi":"10.1109/ISIE.2003.1267984","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267984","url":null,"abstract":"This paper proposes a new scheme to guarantee speed sensorless control and optimal field orientation of surface permanent magnet synchronous motors (SPMSMs) even if parameter deviations occur and initial rotor position is unknown. A novel adaptive sliding-mode observer is used for field oriented speed sensorless control. First the induced e.m.f. components are observed using the sliding-mode technique with an adaptive switching gain. Then a low-pass filter with an adaptive amplitude compensator, that works as derivative observer, is used to get rid of the chattering noise of estimated e.m.f. components and to calculate rotor speed and position. The current components in rotor reference frame are estimated from the active and reactive electromagnetic torques calculated in both the stationary reference frame and the estimated rotor one. The latter is also used as control reference frame. Inverter, filters and observer cause unavoidable and unpredictable time-delay in rotor position estimation, so that the control reference frame is delayed as to the actual rotor one. As a consequence, field orientation and maximum torque/current ratio do not occur when the desired field oriented current references are imposed in the control reference frame. An original field orientation PI controller is used to provide the appropriate current references in the control reference frame. Test results are presented to prove the approach effectiveness.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"298 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132495318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-06-09DOI: 10.1109/ISIE.2003.1267287
C. Petry, J. Fagundes, I. Barbi
This paper presents new AC-AC converter topologies as AC voltage regulators. Operation stages, static gain expressions, main waveforms and simulation results are shown. Laboratory experimental results for 1 kVA converters are also presented, which demonstrates the feasibility of the study carried out.
{"title":"New AC-AC converter topologies","authors":"C. Petry, J. Fagundes, I. Barbi","doi":"10.1109/ISIE.2003.1267287","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267287","url":null,"abstract":"This paper presents new AC-AC converter topologies as AC voltage regulators. Operation stages, static gain expressions, main waveforms and simulation results are shown. Laboratory experimental results for 1 kVA converters are also presented, which demonstrates the feasibility of the study carried out.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133320685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-06-09DOI: 10.1109/ISIE.2003.1267314
A. Bauchspiess, B. Guimarães, H.L. Gosmann
A remote laboratory for long-distance education is presented: the level control of three coupled water reservoirs. This process is non-linear and multivariable so that different control problems and strategies can be shown. The user can control and visualize the experiment in real-time using a standard Web browser; no additional software is required. PID, state-space, fuzzy and exact linearization have been implemented on this process. Multivariable PID with the most common references are already available for remote experimentation.
{"title":"Remote experimentation on a three coupled water reservoirs","authors":"A. Bauchspiess, B. Guimarães, H.L. Gosmann","doi":"10.1109/ISIE.2003.1267314","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267314","url":null,"abstract":"A remote laboratory for long-distance education is presented: the level control of three coupled water reservoirs. This process is non-linear and multivariable so that different control problems and strategies can be shown. The user can control and visualize the experiment in real-time using a standard Web browser; no additional software is required. PID, state-space, fuzzy and exact linearization have been implemented on this process. Multivariable PID with the most common references are already available for remote experimentation.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121974269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2003-06-09DOI: 10.1109/ISIE.2003.1267322
J. B. Cunha
The number of applications using machine vision and digital image processing techniques in the agricultural sector is increasing rapidly. These applications include land/aerial remote sensing of crops, detection and recognition of pathological stress conditions, shape and color characterization of fruits, among many other topics. In fact, quantification of the visual properties of horticultural products and plants can play an important role to improve and automate agricultural management tasks. In this paper, is described a plant leaf characterization system based on a personal computer. This system uses a digital scanner to acquire leaf images with a resolution of 150 dpi. These images are afterwards processed in order to compute some leaf characteristic parameters, such as: leaf area and perimeter, existence of holes, width and length. With the implemented algorithms the errors between the measurements and the real values were typically less than /spl mnplus/3% and /spl mnplus/2.5% for the area and linear measurements, respectively. These tests and results were realized using sets of known size images and leaf images that were measured with the proposed system and with a commercial calibrated leaf area system LiCor from Delta-T devices.
{"title":"Application of image processing techniques in the characterization of plant leafs","authors":"J. B. Cunha","doi":"10.1109/ISIE.2003.1267322","DOIUrl":"https://doi.org/10.1109/ISIE.2003.1267322","url":null,"abstract":"The number of applications using machine vision and digital image processing techniques in the agricultural sector is increasing rapidly. These applications include land/aerial remote sensing of crops, detection and recognition of pathological stress conditions, shape and color characterization of fruits, among many other topics. In fact, quantification of the visual properties of horticultural products and plants can play an important role to improve and automate agricultural management tasks. In this paper, is described a plant leaf characterization system based on a personal computer. This system uses a digital scanner to acquire leaf images with a resolution of 150 dpi. These images are afterwards processed in order to compute some leaf characteristic parameters, such as: leaf area and perimeter, existence of holes, width and length. With the implemented algorithms the errors between the measurements and the real values were typically less than /spl mnplus/3% and /spl mnplus/2.5% for the area and linear measurements, respectively. These tests and results were realized using sets of known size images and leaf images that were measured with the proposed system and with a commercial calibrated leaf area system LiCor from Delta-T devices.","PeriodicalId":166431,"journal":{"name":"2003 IEEE International Symposium on Industrial Electronics ( Cat. No.03TH8692)","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114822802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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