Balancing high display performance with energy efficiency is crucial for global sustainability.Lowering operating frequencies—such as enabling 1 Hz operation in fringe-field switching(FFS)liquid crystal displays—red...Balancing high display performance with energy efficiency is crucial for global sustainability.Lowering operating frequencies—such as enabling 1 Hz operation in fringe-field switching(FFS)liquid crystal displays—reduces power consumption but is hindered by image flicker.While negative dielectric anisotropy liquid crystals(nLCs)mitigate flicker,their high driving voltages and production costs limit adoption.Positive dielectric anisotropy liquid crystals(pLCs)offer lower operating voltages,faster response times,and broader applicability,making them a more viable alternative.This study introduces a novel approach to minimizing flexoelectric effects in pLCs by investigating how single components influence flexoelectric behavior in mixtures through an effective experimental methodology.Two innovative measurement techniques—(1)flexoelectric coefficient difference analysis and(2)displacement-current measurement(DCM)—are presented,marking the first application of DCM for verifying flexoelectric effects.The proposed system eliminates uncertainties associated with previous methods,providing a reliable framework for selecting liquid crystal components with minimal flexoelectric effects while preserving key electro-optic properties.Given pLCs'higher reliability,lower production costs,and broader material selection,these advancements hold significant potential for low-power displays.We believe this work enhances flexoelectric analysis in nematic liquid crystals and contributes to sustainable innovation in the display industry,aligning with global energy-saving goals.展开更多
Intensity flicker is a common form of degradation in archived film. Most algorithms on this distortion are complicated and uncontrolled. This paper presented a discrete mathematical model of flicker, designed a block-...Intensity flicker is a common form of degradation in archived film. Most algorithms on this distortion are complicated and uncontrolled. This paper presented a discrete mathematical model of flicker, designed a block-based estimation method of the model＇s parameters according to their features of intensity variation in large area. With this estimation result it constructed a compensation model to repair the current frame. This restoration approach is full automatic and the repair process of current frame does not need the information of frames behind it. The algorithm was realized to establish a simple and adjustable repair system. The experimental results show that the proposed algorithm can remove most intensity flicker and preserve tho wanted effects.展开更多
AIM: To investigate the effectiveness and feasibility of inducing myopia in guinea pigs by flickering light (FL) stimulation with different frequencies. METHODS: Seventy 2 -week-old guinea pigs were randomly assigned ...AIM: To investigate the effectiveness and feasibility of inducing myopia in guinea pigs by flickering light (FL) stimulation with different frequencies. METHODS: Seventy 2 -week-old guinea pigs were randomly assigned to six groups: five FL groups and a control group (n =12 for each). Animals in the five FL groups were raised under 500lx illumination with a duty diurnal cycle of 50% at a flash rate of 5, 1, 0.5, 0.25 and 0.1Hz respectively. Those in the control group were reared under steady 250lx illumination. Refraction, axial length, and radius of curvature were measured before and at 2, 4, 6, 8, 10 and 12 weeks after treatment. At week 12, the eyeballs were taken out and three ocular dimensions and dry weight of sclera were measured. RESULTS: A myopic shift and axial eye length increase developed in the five FL groups. Stimulation at 0.5Hz caused greater changes in myopic shift, axial elongation, eyeball dimension, and dry weight of sclera than stimulation at other frequencies. Compared with controls, eyes in 0.5Hz group were approximately -5.5 ±1.5D more myopic with increase in horizontal, vertical, axial dimensions by 0.89 ±0.3mm, 0.69 ±0.2mm, 1.12 ±0.2mm respectively and with increase in dry weight of sclera by 0.44mg. CONCLUSION: Chronic exposure to periodic illumination at temporal frequency is attended by development of excessive ocular enlargement and myopic refractive error. Emmetropization could bedisrupted differently by frequency alteration.展开更多
BACKGROUND:Minimal hepatic encephalopathy (MHE) impairs quality of life and predicts overt hepatic encephalopathy (HE) in cirrhotic patients.Diagnosis of MHE requires cumbersome tests.Lactulose is effective in the tre...BACKGROUND:Minimal hepatic encephalopathy (MHE) impairs quality of life and predicts overt hepatic encephalopathy (HE) in cirrhotic patients.Diagnosis of MHE requires cumbersome tests.Lactulose is effective in the treatment of MHE.This study aimed to evaluate the use of critical flicker frequency (CFF) for the diagnosis of MHE in cirrhotic patients after treatment.METHODS:One hundred and ten patients were evaluated by psychometry (number connection tests A,B or figure connection tests A,B),P300 auditory event related potential (P300ERP),venous ammonia,and CFF for MHE.MHE was diagnosed by abnormal psychometry (>2SD age matched controls) and P300ERP.MHE patients were treated with lactulose for one month.Response was defined by normalization (<2SD of matched controls) of both psychometry and P300ERP.RESULTS:Of the 110 patients [Child Turcott Pugh score A:B:C 39:42:29,(age 41.6±11.6 years,M:F 82:28)],75 (68%) had abnormal results of psychometric tests,and 74 (67%) had prolonged P300ERP.Fifteen (20%) patients with abnormal results of psychometric tests had normal P300ERP.Thus sixty (54.5%) patients were diagnosed as having MHE.After treatment for one month,34 (57%) recovered while 26 (43%) continued to have abnormal resents of psychometric or P300ERP tests.CFF was <39 Hz in 72 (65.4%) patients before treatment and in 20 (33.3%) after treatment.CFF sensitivity,specificity,positive predictive value,negative predictive value,and diagnostic accuracy for the assessment of recovery of MHE were 65%,91%,85%,77% and 80%,respectively.CONCLUSION:CFF is a simple,relatively reliable,and accurate test without any dependence on age or literacy in the diagnosis and assessment of recovery of patients with MHE.展开更多
In this paper, motion analysis methods based on the moment features and flicker frequency features for early fire flame from ordinary CCD video camera were proposed, and in order to describe the changing of flame and ...In this paper, motion analysis methods based on the moment features and flicker frequency features for early fire flame from ordinary CCD video camera were proposed, and in order to describe the changing of flame and disturbance of non-flame phenomena further more, the average changing pixel number of the first-order moments of consecutive flames has been defined in the moment analysis as well. The first-order moments of all kinds of flames used in our experiments present irregularly flickering, and their average changing pixel numbers of first-order moments are greater than fire-like disturbances. For the analysis of flicker frequency of flame, which is extracted and calculated in spatial domain, and therefore it is computational simple and fast. The method of extracting flicker frequency from video images is not affected by the catalogues of combustion material and distance. In experiments, we adopted two kinds of flames, i. e. , fixed flame and movable flame. Many comparing and disturbing experiments were done and verified that the methods can be used as criteria for early fire detection.展开更多
A brain-computer interface(BCI)system based on steady-state visual evoked potentials(SSVEP)was developed by four-class phase-coded stimuli.SSVEPs elicited by flickers at 60Hz,which is higher than the critical fusion f...A brain-computer interface(BCI)system based on steady-state visual evoked potentials(SSVEP)was developed by four-class phase-coded stimuli.SSVEPs elicited by flickers at 60Hz,which is higher than the critical fusion frequency(CFF),were compared with those at 15Hz and 30Hz.SSVEP components in electroencephalogram(EEG)were detected using task related component analysis(TRCA)method.Offline analysis with 17 subjects indicated that the highest information transfer rate(ITR)was 29.80±4.65bpm with 0.5s data length for 60Hz and the classification accuracy was 70.07±4.15%.The online BCI system reached an averaged classification accuracy of 87.75±3.50%at 60Hz with 4s,resulting in an ITR of 16.73±1.63bpm.In particular,the maximum ITR for a subject was 80bpm with 0.5s at 60Hz.Although the BCI performance of 60Hz was lower than that of 15Hz and 30Hz,the results of the behavioral test indicated that,with no perception of flicker,the BCI system with 60Hz was more comfortable to use than 15Hz and 30Hz.Correlation analysis revealed that SSVEP with higher signal-to-noise ratio(SNR)corresponded to better classification performance and the improvement in comfortableness was accompanied by a decrease in performance.This study demonstrates the feasibility and potential of a user-friendly SSVEP-based BCI using imperceptible flickers.展开更多
In this paper we examine the flicker of commercial LED lamps and with the help of volunteers we explore the parameter space (frequency and duty cycle) in order to find pulsing operating conditions under which the ligh...In this paper we examine the flicker of commercial LED lamps and with the help of volunteers we explore the parameter space (frequency and duty cycle) in order to find pulsing operating conditions under which the light fluctuations are not visually perceived. The results show that LEDs under mains voltage manifest the most extreme cases of flicker and we also confirm that under pulsing mode the overall impression is of higher brightness which is an opportunity for energy savings. The results also show that the background color and luminance contrast is of high importance. Finally we propose an easy method for consumers to detect flickering of light sources under mains voltage.展开更多
Objective In order to red uc e the flicker in color plasma display panel (PDP), the highly peaked light outpu t at certain positions and the strong luminance difference among subfields, whic h cause flicker in PDP, i...Objective In order to red uc e the flicker in color plasma display panel (PDP), the highly peaked light outpu t at certain positions and the strong luminance difference among subfields, whic h cause flicker in PDP, is analyzed; and a flicker index method is developed to evaluate flicker in PDP based on the flicker theory and the electroencephalograp h response model for luminance. Methods This method considers f licker as a main result of the fundamental frequency component of luminance supe rimposed on the DC-component, the flicker index is defined as ratio between the positive square roots of the sum of the two square components. Results & Conclusion The calculation results of flicker index indicate that flicker can be obviously weakened via increase of subfield number, symmetrical s election and homogeneous interlaced distribution of major weight subfields . Fli cker can be further reduced by choosing the suitable subfield order according to gray scale region of image.展开更多
AIM:To evaluate the different visual pathways represented by the Heidelberg Engineering Perimeter flicker defined form and RareBit(magnocellular and parvocellular respectively)in different age-groups and according to ...AIM:To evaluate the different visual pathways represented by the Heidelberg Engineering Perimeter flicker defined form and RareBit(magnocellular and parvocellular respectively)in different age-groups and according to the fatigue.METHODS:Totally 64 eyes of 32 healthy subjects were included in the prospective study.Each participant underwent screening—ophthalmic examination including best-corrected visual acuity,anterior and posterior segment assessment,and visual field examination with Heidelberg Edge Perimetry(HEP)-standard automated perimeter(SAP)24-2.They were observed for 2 y previously to the enrollment.This helped to define that the enrolled patients did not bear the glaucoma-developing potential.During the screening and after two years the HEP had been conducted in the standard protocol 24-2 and RareBit perimetry(RBP)in accordance with the manufacturer’s description.Participants were randomly assigned to the groups:flicker defined form(FDF)-first or RBP-first.This defined from which additional visual field test the participant started.Participants were additionally subdivided to younger and older study groups.The effect of subject variables was explored with Mann-Whitney U-test.Testing for the presence of correlations between parameters was performed using the Spearman Rank Order Correlations and confirmed by the parametric tests.For the influence of additional factors,the Kruskal-Wallis test was performed.RESULTS:The positive correlation between meandeviation(MD)and mean hit rate(MHR)and pattern standard deviation(PSD)and standard deviation of MHR(±MHR)were found in younger study group(P=0.005,r=0.481 and P=0.0074,r=0.465),whereas in the older subgroup no correlation was observed.Additionally,the randomization protocol helped in defining the role of fatigue on the HEP-FDF results.Participant for whom the HEPFDF was performed after RareBit had significantly worse results than those for whom the HEP-FDF was first.In the younger group,the MHR and±MHR depend from age in that group(P<0.05,r=0.43 and r=-0.57 respectively)while no age-dependent differences were found in HEPrelated parameters.On the contrary in the older group the MD and PSD varies with age(P<0.05,r=0.47 and r=-0.44 respectively)while the RBP parameters remained unchanged.The questionnaire showed that participants preferred RareBit over HEP-FDF in terms of a duration time,comfort,understanding of the test procedures,and ocular pain(P<0.05).CONCLUSION:The influence of patient’s fatigue should be considered during HEP-FDF examination.An overlap hypothesis should be reevaluated after determining of other factors that affect HEP-FDF and RareBit results.展开更多
Flicker electroretinograms(FERGs)of 30Hz were recorded for 46eyes(23 cases)of low vision,including 38 eyes with retinal diseases and 8eyes with optic neuropathy,and for 39 normal eyes(33 cases).The recordedwave forms ...Flicker electroretinograms(FERGs)of 30Hz were recorded for 46eyes(23 cases)of low vision,including 38 eyes with retinal diseases and 8eyes with optic neuropathy,and for 39 normal eyes(33 cases).The recordedwave forms were analysed by two methods:(1)to measure the peak to peakamplitude and pseudophase directly,and(2)to measure the amplitude andphase of fundamental response component(30Hz)by discrete Fourier trans-form(DFT).The abnormality ratios between these two methods were com-pared in low vision pati...展开更多
BACKGROUND Critical flicker frequency(CFF)is a quantitative tool for assessing hepatic enceph-alopathy(HE),particularly minimal HE,which is associated with poor prognosis in liver cirrhosis.Alcohol-related liver disea...BACKGROUND Critical flicker frequency(CFF)is a quantitative tool for assessing hepatic enceph-alopathy(HE),particularly minimal HE,which is associated with poor prognosis in liver cirrhosis.Alcohol-related liver disease(ALD)is a leading global cause of cirrhosis;however,the effects of alcohol on CFF and its relationship with liver stiffness(LS)remain underexplored.AIM To study the impact of alcohol withdrawal on CFF and its correlation with LS in ALD patients.METHODS A total of 108 patients were included:93 heavy drinkers hospitalized for detoxi-fication,15 with non-ALD etiologies,and 20 healthy controls.CFF was measured using the Hepatonorm analyzer,and LS via transient elastography(FibroScan).Baseline and post-detoxification assessments were conducted in 57 ALD patients.RESULTS The cohort had a mean age of 53.7±13.8 years,with 74% male participants.CFF measurements were reliable,with 97.2% of patients showing an interquartile range<20%.ALD patients exhibited significantly lower CFF compared to controls.Receiver operating characteristic analysis for overt HE(n=12)yielded an area under the curve of 0.66(95%confidence interval:0.49-0.84,P=0.0142),with an optimal cutoff of 36.5 Hz.CFF significantly improved post-detoxification.Patients with LS>17 kPa had lower CFF,while those with intermediate LS showed no significant difference.CONCLUSION CFF is influenced by HE severity and acute alcohol exposure,showing improvement after detoxification.Its weak correlation with fibrosis stage suggests that CFF serves as a sensitive neurocognitive marker in ALD.展开更多
Fast fluctuations in wind farm power produce voltage flicker in the network.One way to mitigate the flicker is to place a static VAr compensator(SVC).Due to the operating delay of SVCs,it is essential to predict the w...Fast fluctuations in wind farm power produce voltage flicker in the network.One way to mitigate the flicker is to place a static VAr compensator(SVC).Due to the operating delay of SVCs,it is essential to predict the wind farm reactive power.Here,a novel fuzzy nonlinear modeling approach is suggested and used in the one-step-ahead prediction of the power characteristics.The base of the developed fuzzy modeling is the Takagi-Sugeno fuzzy representation and a dual-unscented Kalman filter(D-UKF).In other words,a nonlinear TS fuzzy system is trained online via the D-UKF.The forecasted value is used as the SVC’s reference signal.A large amount of actual data gathered from a wind farm is used for the performance evaluation.This data is collected in winter and summer for different climate situations.Using the actual data,a current source with changing amplitude and phase which is updated every half-cycle,is used to model the wind farm.Numerical results,including the flicker indices,confirm the improvement in the SVC’s performance.展开更多
基金supported by Basic Science Research Program through the National Research Foundation(NRF)of Korea,funded by the Ministry of Science and ICT(MSIT),Korea[2022R1A2C2091671]by ITECH R&D Program of MOTIE/KEIT(Ministry of Trade,Industry&Energy/Korea Evaluation Institute of Industrial Technology)[20016808].
文摘Balancing high display performance with energy efficiency is crucial for global sustainability.Lowering operating frequencies—such as enabling 1 Hz operation in fringe-field switching(FFS)liquid crystal displays—reduces power consumption but is hindered by image flicker.While negative dielectric anisotropy liquid crystals(nLCs)mitigate flicker,their high driving voltages and production costs limit adoption.Positive dielectric anisotropy liquid crystals(pLCs)offer lower operating voltages,faster response times,and broader applicability,making them a more viable alternative.This study introduces a novel approach to minimizing flexoelectric effects in pLCs by investigating how single components influence flexoelectric behavior in mixtures through an effective experimental methodology.Two innovative measurement techniques—(1)flexoelectric coefficient difference analysis and(2)displacement-current measurement(DCM)—are presented,marking the first application of DCM for verifying flexoelectric effects.The proposed system eliminates uncertainties associated with previous methods,providing a reliable framework for selecting liquid crystal components with minimal flexoelectric effects while preserving key electro-optic properties.Given pLCs'higher reliability,lower production costs,and broader material selection,these advancements hold significant potential for low-power displays.We believe this work enhances flexoelectric analysis in nematic liquid crystals and contributes to sustainable innovation in the display industry,aligning with global energy-saving goals.
基金National Natural Science Foundation ofChina(No.69905003)
文摘Intensity flicker is a common form of degradation in archived film. Most algorithms on this distortion are complicated and uncontrolled. This paper presented a discrete mathematical model of flicker, designed a block-based estimation method of the model＇s parameters according to their features of intensity variation in large area. With this estimation result it constructed a compensation model to repair the current frame. This restoration approach is full automatic and the repair process of current frame does not need the information of frames behind it. The algorithm was realized to establish a simple and adjustable repair system. The experimental results show that the proposed algorithm can remove most intensity flicker and preserve tho wanted effects.
基金Foundation for Shanghai Municipal Health Bureau (No. 2010147)National Natural Science Foundation of China (No. 81100689)Foundation for Shanghai Jinshan Health Bureau (No. JWKJ-KTYQ-201203)
文摘AIM: To investigate the effectiveness and feasibility of inducing myopia in guinea pigs by flickering light (FL) stimulation with different frequencies. METHODS: Seventy 2 -week-old guinea pigs were randomly assigned to six groups: five FL groups and a control group (n =12 for each). Animals in the five FL groups were raised under 500lx illumination with a duty diurnal cycle of 50% at a flash rate of 5, 1, 0.5, 0.25 and 0.1Hz respectively. Those in the control group were reared under steady 250lx illumination. Refraction, axial length, and radius of curvature were measured before and at 2, 4, 6, 8, 10 and 12 weeks after treatment. At week 12, the eyeballs were taken out and three ocular dimensions and dry weight of sclera were measured. RESULTS: A myopic shift and axial eye length increase developed in the five FL groups. Stimulation at 0.5Hz caused greater changes in myopic shift, axial elongation, eyeball dimension, and dry weight of sclera than stimulation at other frequencies. Compared with controls, eyes in 0.5Hz group were approximately -5.5 ±1.5D more myopic with increase in horizontal, vertical, axial dimensions by 0.89 ±0.3mm, 0.69 ±0.2mm, 1.12 ±0.2mm respectively and with increase in dry weight of sclera by 0.44mg. CONCLUSION: Chronic exposure to periodic illumination at temporal frequency is attended by development of excessive ocular enlargement and myopic refractive error. Emmetropization could bedisrupted differently by frequency alteration.
文摘BACKGROUND:Minimal hepatic encephalopathy (MHE) impairs quality of life and predicts overt hepatic encephalopathy (HE) in cirrhotic patients.Diagnosis of MHE requires cumbersome tests.Lactulose is effective in the treatment of MHE.This study aimed to evaluate the use of critical flicker frequency (CFF) for the diagnosis of MHE in cirrhotic patients after treatment.METHODS:One hundred and ten patients were evaluated by psychometry (number connection tests A,B or figure connection tests A,B),P300 auditory event related potential (P300ERP),venous ammonia,and CFF for MHE.MHE was diagnosed by abnormal psychometry (>2SD age matched controls) and P300ERP.MHE patients were treated with lactulose for one month.Response was defined by normalization (<2SD of matched controls) of both psychometry and P300ERP.RESULTS:Of the 110 patients [Child Turcott Pugh score A:B:C 39:42:29,(age 41.6±11.6 years,M:F 82:28)],75 (68%) had abnormal results of psychometric tests,and 74 (67%) had prolonged P300ERP.Fifteen (20%) patients with abnormal results of psychometric tests had normal P300ERP.Thus sixty (54.5%) patients were diagnosed as having MHE.After treatment for one month,34 (57%) recovered while 26 (43%) continued to have abnormal resents of psychometric or P300ERP tests.CFF was <39 Hz in 72 (65.4%) patients before treatment and in 20 (33.3%) after treatment.CFF sensitivity,specificity,positive predictive value,negative predictive value,and diagnostic accuracy for the assessment of recovery of MHE were 65%,91%,85%,77% and 80%,respectively.CONCLUSION:CFF is a simple,relatively reliable,and accurate test without any dependence on age or literacy in the diagnosis and assessment of recovery of patients with MHE.
基金Supported by " Experimental Scale Studies in Smoke Control Strategy in Large Linear Atria in HKSAR" (B Q372)
文摘In this paper, motion analysis methods based on the moment features and flicker frequency features for early fire flame from ordinary CCD video camera were proposed, and in order to describe the changing of flame and disturbance of non-flame phenomena further more, the average changing pixel number of the first-order moments of consecutive flames has been defined in the moment analysis as well. The first-order moments of all kinds of flames used in our experiments present irregularly flickering, and their average changing pixel numbers of first-order moments are greater than fire-like disturbances. For the analysis of flicker frequency of flame, which is extracted and calculated in spatial domain, and therefore it is computational simple and fast. The method of extracting flicker frequency from video images is not affected by the catalogues of combustion material and distance. In experiments, we adopted two kinds of flames, i. e. , fixed flame and movable flame. Many comparing and disturbing experiments were done and verified that the methods can be used as criteria for early fire detection.
基金supported by the National Key R&D Program of China under grant 2017YFA0205903the National Natural Science Foundation of China under grant 62071447+1 种基金the Beijing Science and Technology Program under grant Z201100004420015the Strategic Priority Research Program of Chinese Academy of Science under grant XDB32040200.
文摘A brain-computer interface(BCI)system based on steady-state visual evoked potentials(SSVEP)was developed by four-class phase-coded stimuli.SSVEPs elicited by flickers at 60Hz,which is higher than the critical fusion frequency(CFF),were compared with those at 15Hz and 30Hz.SSVEP components in electroencephalogram(EEG)were detected using task related component analysis(TRCA)method.Offline analysis with 17 subjects indicated that the highest information transfer rate(ITR)was 29.80±4.65bpm with 0.5s data length for 60Hz and the classification accuracy was 70.07±4.15%.The online BCI system reached an averaged classification accuracy of 87.75±3.50%at 60Hz with 4s,resulting in an ITR of 16.73±1.63bpm.In particular,the maximum ITR for a subject was 80bpm with 0.5s at 60Hz.Although the BCI performance of 60Hz was lower than that of 15Hz and 30Hz,the results of the behavioral test indicated that,with no perception of flicker,the BCI system with 60Hz was more comfortable to use than 15Hz and 30Hz.Correlation analysis revealed that SSVEP with higher signal-to-noise ratio(SNR)corresponded to better classification performance and the improvement in comfortableness was accompanied by a decrease in performance.This study demonstrates the feasibility and potential of a user-friendly SSVEP-based BCI using imperceptible flickers.
文摘In this paper we examine the flicker of commercial LED lamps and with the help of volunteers we explore the parameter space (frequency and duty cycle) in order to find pulsing operating conditions under which the light fluctuations are not visually perceived. The results show that LEDs under mains voltage manifest the most extreme cases of flicker and we also confirm that under pulsing mode the overall impression is of higher brightness which is an opportunity for energy savings. The results also show that the background color and luminance contrast is of high importance. Finally we propose an easy method for consumers to detect flickering of light sources under mains voltage.
基金Thisprojectwassupportedbythe0205ProjectforScienceandTechnology of china edncation ministry.
文摘Objective In order to red uc e the flicker in color plasma display panel (PDP), the highly peaked light outpu t at certain positions and the strong luminance difference among subfields, whic h cause flicker in PDP, is analyzed; and a flicker index method is developed to evaluate flicker in PDP based on the flicker theory and the electroencephalograp h response model for luminance. Methods This method considers f licker as a main result of the fundamental frequency component of luminance supe rimposed on the DC-component, the flicker index is defined as ratio between the positive square roots of the sum of the two square components. Results & Conclusion The calculation results of flicker index indicate that flicker can be obviously weakened via increase of subfield number, symmetrical s election and homogeneous interlaced distribution of major weight subfields . Fli cker can be further reduced by choosing the suitable subfield order according to gray scale region of image.
基金Supported by the Wroclaw Medical University grant(No.Pbmn-168).
文摘AIM:To evaluate the different visual pathways represented by the Heidelberg Engineering Perimeter flicker defined form and RareBit(magnocellular and parvocellular respectively)in different age-groups and according to the fatigue.METHODS:Totally 64 eyes of 32 healthy subjects were included in the prospective study.Each participant underwent screening—ophthalmic examination including best-corrected visual acuity,anterior and posterior segment assessment,and visual field examination with Heidelberg Edge Perimetry(HEP)-standard automated perimeter(SAP)24-2.They were observed for 2 y previously to the enrollment.This helped to define that the enrolled patients did not bear the glaucoma-developing potential.During the screening and after two years the HEP had been conducted in the standard protocol 24-2 and RareBit perimetry(RBP)in accordance with the manufacturer’s description.Participants were randomly assigned to the groups:flicker defined form(FDF)-first or RBP-first.This defined from which additional visual field test the participant started.Participants were additionally subdivided to younger and older study groups.The effect of subject variables was explored with Mann-Whitney U-test.Testing for the presence of correlations between parameters was performed using the Spearman Rank Order Correlations and confirmed by the parametric tests.For the influence of additional factors,the Kruskal-Wallis test was performed.RESULTS:The positive correlation between meandeviation(MD)and mean hit rate(MHR)and pattern standard deviation(PSD)and standard deviation of MHR(±MHR)were found in younger study group(P=0.005,r=0.481 and P=0.0074,r=0.465),whereas in the older subgroup no correlation was observed.Additionally,the randomization protocol helped in defining the role of fatigue on the HEP-FDF results.Participant for whom the HEPFDF was performed after RareBit had significantly worse results than those for whom the HEP-FDF was first.In the younger group,the MHR and±MHR depend from age in that group(P<0.05,r=0.43 and r=-0.57 respectively)while no age-dependent differences were found in HEPrelated parameters.On the contrary in the older group the MD and PSD varies with age(P<0.05,r=0.47 and r=-0.44 respectively)while the RBP parameters remained unchanged.The questionnaire showed that participants preferred RareBit over HEP-FDF in terms of a duration time,comfort,understanding of the test procedures,and ocular pain(P<0.05).CONCLUSION:The influence of patient’s fatigue should be considered during HEP-FDF examination.An overlap hypothesis should be reevaluated after determining of other factors that affect HEP-FDF and RareBit results.
文摘Flicker electroretinograms(FERGs)of 30Hz were recorded for 46eyes(23 cases)of low vision,including 38 eyes with retinal diseases and 8eyes with optic neuropathy,and for 39 normal eyes(33 cases).The recordedwave forms were analysed by two methods:(1)to measure the peak to peakamplitude and pseudophase directly,and(2)to measure the amplitude andphase of fundamental response component(30Hz)by discrete Fourier trans-form(DFT).The abnormality ratios between these two methods were com-pared in low vision pati...
文摘BACKGROUND Critical flicker frequency(CFF)is a quantitative tool for assessing hepatic enceph-alopathy(HE),particularly minimal HE,which is associated with poor prognosis in liver cirrhosis.Alcohol-related liver disease(ALD)is a leading global cause of cirrhosis;however,the effects of alcohol on CFF and its relationship with liver stiffness(LS)remain underexplored.AIM To study the impact of alcohol withdrawal on CFF and its correlation with LS in ALD patients.METHODS A total of 108 patients were included:93 heavy drinkers hospitalized for detoxi-fication,15 with non-ALD etiologies,and 20 healthy controls.CFF was measured using the Hepatonorm analyzer,and LS via transient elastography(FibroScan).Baseline and post-detoxification assessments were conducted in 57 ALD patients.RESULTS The cohort had a mean age of 53.7±13.8 years,with 74% male participants.CFF measurements were reliable,with 97.2% of patients showing an interquartile range<20%.ALD patients exhibited significantly lower CFF compared to controls.Receiver operating characteristic analysis for overt HE(n=12)yielded an area under the curve of 0.66(95%confidence interval:0.49-0.84,P=0.0142),with an optimal cutoff of 36.5 Hz.CFF significantly improved post-detoxification.Patients with LS>17 kPa had lower CFF,while those with intermediate LS showed no significant difference.CONCLUSION CFF is influenced by HE severity and acute alcohol exposure,showing improvement after detoxification.Its weak correlation with fibrosis stage suggests that CFF serves as a sensitive neurocognitive marker in ALD.
文摘Fast fluctuations in wind farm power produce voltage flicker in the network.One way to mitigate the flicker is to place a static VAr compensator(SVC).Due to the operating delay of SVCs,it is essential to predict the wind farm reactive power.Here,a novel fuzzy nonlinear modeling approach is suggested and used in the one-step-ahead prediction of the power characteristics.The base of the developed fuzzy modeling is the Takagi-Sugeno fuzzy representation and a dual-unscented Kalman filter(D-UKF).In other words,a nonlinear TS fuzzy system is trained online via the D-UKF.The forecasted value is used as the SVC’s reference signal.A large amount of actual data gathered from a wind farm is used for the performance evaluation.This data is collected in winter and summer for different climate situations.Using the actual data,a current source with changing amplitude and phase which is updated every half-cycle,is used to model the wind farm.Numerical results,including the flicker indices,confirm the improvement in the SVC’s performance.
